drivers/spi/spi.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 // SPI init/core code
   3 //
   4 // Copyright (C) 2005 David Brownell
   5 // Copyright (C) 2008 Secret Lab Technologies Ltd.
   6
   7 #include <linux/kernel.h>
   8 #include <linux/device.h>
   9 #include <linux/init.h>
  10 #include <linux/cache.h>
  11 #include <linux/dma-mapping.h>
  12 #include <linux/dmaengine.h>
  13 #include <linux/mutex.h>
  14 #include <linux/of_device.h>
  15 #include <linux/of_irq.h>
  16 #include <linux/clk/clk-conf.h>
  17 #include <linux/slab.h>
  18 #include <linux/mod_devicetable.h>
  19 #include <linux/spi/spi.h>
  20 #include <linux/spi/spi-mem.h>
  21 #include <linux/of_gpio.h>
  22 #include <linux/gpio/consumer.h>
  23 #include <linux/pm_runtime.h>
  24 #include <linux/pm_domain.h>
  25 #include <linux/property.h>
  26 #include <linux/export.h>
  27 #include <linux/sched/rt.h>
  28 #include <uapi/linux/sched/types.h>
  29 #include <linux/delay.h>
  30 #include <linux/kthread.h>
  31 #include <linux/ioport.h>
  32 #include <linux/acpi.h>
  33 #include <linux/highmem.h>
  34 #include <linux/idr.h>
  35 #include <linux/platform_data/x86/apple.h>
  36
  37 #define CREATE_TRACE_POINTS
  38 #include <trace/events/spi.h>
  39 EXPORT_TRACEPOINT_SYMBOL(spi_transfer_start);
  40 EXPORT_TRACEPOINT_SYMBOL(spi_transfer_stop);
  41
  42 #include "internals.h"
  43
  44 static DEFINE_IDR(spi_master_idr);
  45
  46 static void spidev_release(struct device *dev)
  47 {
  48         struct spi_device       *spi = to_spi_device(dev);
  49
  50         /* spi controllers may cleanup for released devices */
  51         if (spi->controller->cleanup)
  52                 spi->controller->cleanup(spi);
  53
  54         spi_controller_put(spi->controller);
  55         kfree(spi->driver_override);
  56         kfree(spi);
  57 }
  58
  59 static ssize_t
  60 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
  61 {
  62         const struct spi_device *spi = to_spi_device(dev);
  63         int len;
  64
  65         len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
  66         if (len != -ENODEV)
  67                 return len;
  68
  69         return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
  70 }
  71 static DEVICE_ATTR_RO(modalias);
  72
  73 static ssize_t driver_override_store(struct device *dev,
  74                                      struct device_attribute *a,
  75                                      const char *buf, size_t count)
  76 {
  77         struct spi_device *spi = to_spi_device(dev);
  78         const char *end = memchr(buf, '\n', count);
  79         const size_t len = end ? end - buf : count;
  80         const char *driver_override, *old;
  81
  82         /* We need to keep extra room for a newline when displaying value */
  83         if (len >= (PAGE_SIZE - 1))
  84                 return -EINVAL;
  85
  86         driver_override = kstrndup(buf, len, GFP_KERNEL);
  87         if (!driver_override)
  88                 return -ENOMEM;
  89
  90         device_lock(dev);
  91         old = spi->driver_override;
  92         if (len) {
  93                 spi->driver_override = driver_override;
  94         } else {
  95                 /* Empty string, disable driver override */
  96                 spi->driver_override = NULL;
  97                 kfree(driver_override);
  98         }
  99         device_unlock(dev);
 100         kfree(old);
 101
 102         return count;
 103 }
 104
 105 static ssize_t driver_override_show(struct device *dev,
 106                                     struct device_attribute *a, char *buf)
 107 {
 108         const struct spi_device *spi = to_spi_device(dev);
 109         ssize_t len;
 110
 111         device_lock(dev);
 112         len = snprintf(buf, PAGE_SIZE, "%s\n", spi->driver_override ? : "");
 113         device_unlock(dev);
 114         return len;
 115 }
 116 static DEVICE_ATTR_RW(driver_override);
 117
 118 #define SPI_STATISTICS_ATTRS(field, file)                               \
 119 static ssize_t spi_controller_##field##_show(struct device *dev,        \
 120                                              struct device_attribute *attr, \
 121                                              char *buf)                 \
 122 {                                                                       \
 123         struct spi_controller *ctlr = container_of(dev,                 \
 124                                          struct spi_controller, dev);   \
 125         return spi_statistics_##field##_show(&ctlr->statistics, buf);   \
 126 }                                                                       \
 127 static struct device_attribute dev_attr_spi_controller_##field = {      \
 128         .attr = { .name = file, .mode = 0444 },                         \
 129         .show = spi_controller_##field##_show,                          \
 130 };                                                                      \
 131 static ssize_t spi_device_##field##_show(struct device *dev,            \
 132                                          struct device_attribute *attr, \
 133                                         char *buf)                      \
 134 {                                                                       \
 135         struct spi_device *spi = to_spi_device(dev);                    \
 136         return spi_statistics_##field##_show(&spi->statistics, buf);    \
 137 }                                                                       \
 138 static struct device_attribute dev_attr_spi_device_##field = {          \
 139         .attr = { .name = file, .mode = 0444 },                         \
 140         .show = spi_device_##field##_show,                              \
 141 }
 142
 143 #define SPI_STATISTICS_SHOW_NAME(name, file, field, format_string)      \
 144 static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
 145                                             char *buf)                  \
 146 {                                                                       \
 147         unsigned long flags;                                            \
 148         ssize_t len;                                                    \
 149         spin_lock_irqsave(&stat->lock, flags);                          \
 150         len = sprintf(buf, format_string, stat->field);                 \
 151         spin_unlock_irqrestore(&stat->lock, flags);                     \
 152         return len;                                                     \
 153 }                                                                       \
 154 SPI_STATISTICS_ATTRS(name, file)
 155
 156 #define SPI_STATISTICS_SHOW(field, format_string)                       \
 157         SPI_STATISTICS_SHOW_NAME(field, __stringify(field),             \
 158                                  field, format_string)
 159
 160 SPI_STATISTICS_SHOW(messages, "%lu");
 161 SPI_STATISTICS_SHOW(transfers, "%lu");
 162 SPI_STATISTICS_SHOW(errors, "%lu");
 163 SPI_STATISTICS_SHOW(timedout, "%lu");
 164
 165 SPI_STATISTICS_SHOW(spi_sync, "%lu");
 166 SPI_STATISTICS_SHOW(spi_sync_immediate, "%lu");
 167 SPI_STATISTICS_SHOW(spi_async, "%lu");
 168
 169 SPI_STATISTICS_SHOW(bytes, "%llu");
 170 SPI_STATISTICS_SHOW(bytes_rx, "%llu");
 171 SPI_STATISTICS_SHOW(bytes_tx, "%llu");
 172
 173 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number)              \
 174         SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index,           \
 175                                  "transfer_bytes_histo_" number,        \
 176                                  transfer_bytes_histo[index],  "%lu")
 177 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0,  "0-1");
 178 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1,  "2-3");
 179 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2,  "4-7");
 180 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3,  "8-15");
 181 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4,  "16-31");
 182 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5,  "32-63");
 183 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6,  "64-127");
 184 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7,  "128-255");
 185 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8,  "256-511");
 186 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9,  "512-1023");
 187 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
 188 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
 189 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
 190 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
 191 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
 192 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
 193 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
 194
 195 SPI_STATISTICS_SHOW(transfers_split_maxsize, "%lu");
 196
 197 static struct attribute *spi_dev_attrs[] = {
 198         &dev_attr_modalias.attr,
 199         &dev_attr_driver_override.attr,
 200         NULL,
 201 };
 202
 203 static const struct attribute_group spi_dev_group = {
 204         .attrs  = spi_dev_attrs,
 205 };
 206
 207 static struct attribute *spi_device_statistics_attrs[] = {
 208         &dev_attr_spi_device_messages.attr,
 209         &dev_attr_spi_device_transfers.attr,
 210         &dev_attr_spi_device_errors.attr,
 211         &dev_attr_spi_device_timedout.attr,
 212         &dev_attr_spi_device_spi_sync.attr,
 213         &dev_attr_spi_device_spi_sync_immediate.attr,
 214         &dev_attr_spi_device_spi_async.attr,
 215         &dev_attr_spi_device_bytes.attr,
 216         &dev_attr_spi_device_bytes_rx.attr,
 217         &dev_attr_spi_device_bytes_tx.attr,
 218         &dev_attr_spi_device_transfer_bytes_histo0.attr,
 219         &dev_attr_spi_device_transfer_bytes_histo1.attr,
 220         &dev_attr_spi_device_transfer_bytes_histo2.attr,
 221         &dev_attr_spi_device_transfer_bytes_histo3.attr,
 222         &dev_attr_spi_device_transfer_bytes_histo4.attr,
 223         &dev_attr_spi_device_transfer_bytes_histo5.attr,
 224         &dev_attr_spi_device_transfer_bytes_histo6.attr,
 225         &dev_attr_spi_device_transfer_bytes_histo7.attr,
 226         &dev_attr_spi_device_transfer_bytes_histo8.attr,
 227         &dev_attr_spi_device_transfer_bytes_histo9.attr,
 228         &dev_attr_spi_device_transfer_bytes_histo10.attr,
 229         &dev_attr_spi_device_transfer_bytes_histo11.attr,
 230         &dev_attr_spi_device_transfer_bytes_histo12.attr,
 231         &dev_attr_spi_device_transfer_bytes_histo13.attr,
 232         &dev_attr_spi_device_transfer_bytes_histo14.attr,
 233         &dev_attr_spi_device_transfer_bytes_histo15.attr,
 234         &dev_attr_spi_device_transfer_bytes_histo16.attr,
 235         &dev_attr_spi_device_transfers_split_maxsize.attr,
 236         NULL,
 237 };
 238
 239 static const struct attribute_group spi_device_statistics_group = {
 240         .name  = "statistics",
 241         .attrs  = spi_device_statistics_attrs,
 242 };
 243
 244 static const struct attribute_group *spi_dev_groups[] = {
 245         &spi_dev_group,
 246         &spi_device_statistics_group,
 247         NULL,
 248 };
 249
 250 static struct attribute *spi_controller_statistics_attrs[] = {
 251         &dev_attr_spi_controller_messages.attr,
 252         &dev_attr_spi_controller_transfers.attr,
 253         &dev_attr_spi_controller_errors.attr,
 254         &dev_attr_spi_controller_timedout.attr,
 255         &dev_attr_spi_controller_spi_sync.attr,
 256         &dev_attr_spi_controller_spi_sync_immediate.attr,
 257         &dev_attr_spi_controller_spi_async.attr,
 258         &dev_attr_spi_controller_bytes.attr,
 259         &dev_attr_spi_controller_bytes_rx.attr,
 260         &dev_attr_spi_controller_bytes_tx.attr,
 261         &dev_attr_spi_controller_transfer_bytes_histo0.attr,
 262         &dev_attr_spi_controller_transfer_bytes_histo1.attr,
 263         &dev_attr_spi_controller_transfer_bytes_histo2.attr,
 264         &dev_attr_spi_controller_transfer_bytes_histo3.attr,
 265         &dev_attr_spi_controller_transfer_bytes_histo4.attr,
 266         &dev_attr_spi_controller_transfer_bytes_histo5.attr,
 267         &dev_attr_spi_controller_transfer_bytes_histo6.attr,
 268         &dev_attr_spi_controller_transfer_bytes_histo7.attr,
 269         &dev_attr_spi_controller_transfer_bytes_histo8.attr,
 270         &dev_attr_spi_controller_transfer_bytes_histo9.attr,
 271         &dev_attr_spi_controller_transfer_bytes_histo10.attr,
 272         &dev_attr_spi_controller_transfer_bytes_histo11.attr,
 273         &dev_attr_spi_controller_transfer_bytes_histo12.attr,
 274         &dev_attr_spi_controller_transfer_bytes_histo13.attr,
 275         &dev_attr_spi_controller_transfer_bytes_histo14.attr,
 276         &dev_attr_spi_controller_transfer_bytes_histo15.attr,
 277         &dev_attr_spi_controller_transfer_bytes_histo16.attr,
 278         &dev_attr_spi_controller_transfers_split_maxsize.attr,
 279         NULL,
 280 };
 281
 282 static const struct attribute_group spi_controller_statistics_group = {
 283         .name  = "statistics",
 284         .attrs  = spi_controller_statistics_attrs,
 285 };
 286
 287 static const struct attribute_group *spi_master_groups[] = {
 288         &spi_controller_statistics_group,
 289         NULL,
 290 };
 291
 292 void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
 293                                        struct spi_transfer *xfer,
 294                                        struct spi_controller *ctlr)
 295 {
 296         unsigned long flags;
 297         int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
 298
 299         if (l2len < 0)
 300                 l2len = 0;
 301
 302         spin_lock_irqsave(&stats->lock, flags);
 303
 304         stats->transfers++;
 305         stats->transfer_bytes_histo[l2len]++;
 306
 307         stats->bytes += xfer->len;
 308         if ((xfer->tx_buf) &&
 309             (xfer->tx_buf != ctlr->dummy_tx))
 310                 stats->bytes_tx += xfer->len;
 311         if ((xfer->rx_buf) &&
 312             (xfer->rx_buf != ctlr->dummy_rx))
 313                 stats->bytes_rx += xfer->len;
 314
 315         spin_unlock_irqrestore(&stats->lock, flags);
 316 }
 317 EXPORT_SYMBOL_GPL(spi_statistics_add_transfer_stats);
 318
 319 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
 320  * and the sysfs version makes coldplug work too.
 321  */
 322
 323 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
 324                                                 const struct spi_device *sdev)
 325 {
 326         while (id->name[0]) {
 327                 if (!strcmp(sdev->modalias, id->name))
 328                         return id;
 329                 id++;
 330         }
 331         return NULL;
 332 }
 333
 334 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
 335 {
 336         const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
 337
 338         return spi_match_id(sdrv->id_table, sdev);
 339 }
 340 EXPORT_SYMBOL_GPL(spi_get_device_id);
 341
 342 static int spi_match_device(struct device *dev, struct device_driver *drv)
 343 {
 344         const struct spi_device *spi = to_spi_device(dev);
 345         const struct spi_driver *sdrv = to_spi_driver(drv);
 346
 347         /* Check override first, and if set, only use the named driver */
 348         if (spi->driver_override)
 349                 return strcmp(spi->driver_override, drv->name) == 0;
 350
 351         /* Attempt an OF style match */
 352         if (of_driver_match_device(dev, drv))
 353                 return 1;
 354
 355         /* Then try ACPI */
 356         if (acpi_driver_match_device(dev, drv))
 357                 return 1;
 358
 359         if (sdrv->id_table)
 360                 return !!spi_match_id(sdrv->id_table, spi);
 361
 362         return strcmp(spi->modalias, drv->name) == 0;
 363 }
 364
 365 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
 366 {
 367         const struct spi_device         *spi = to_spi_device(dev);
 368         int rc;
 369
 370         rc = acpi_device_uevent_modalias(dev, env);
 371         if (rc != -ENODEV)
 372                 return rc;
 373
 374         return add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
 375 }
 376
 377 struct bus_type spi_bus_type = {
 378         .name           = "spi",
 379         .dev_groups     = spi_dev_groups,
 380         .match          = spi_match_device,
 381         .uevent         = spi_uevent,
 382 };
 383 EXPORT_SYMBOL_GPL(spi_bus_type);
 384
 385
 386 static int spi_drv_probe(struct device *dev)
 387 {
 388         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 389         struct spi_device               *spi = to_spi_device(dev);
 390         int ret;
 391
 392         ret = of_clk_set_defaults(dev->of_node, false);
 393         if (ret)
 394                 return ret;
 395
 396         if (dev->of_node) {
 397                 spi->irq = of_irq_get(dev->of_node, 0);
 398                 if (spi->irq == -EPROBE_DEFER)
 399                         return -EPROBE_DEFER;
 400                 if (spi->irq < 0)
 401                         spi->irq = 0;
 402         }
 403
 404         ret = dev_pm_domain_attach(dev, true);
 405         if (ret)
 406                 return ret;
 407
 408         ret = sdrv->probe(spi);
 409         if (ret)
 410                 dev_pm_domain_detach(dev, true);
 411
 412         return ret;
 413 }
 414
 415 static int spi_drv_remove(struct device *dev)
 416 {
 417         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 418         int ret;
 419
 420         ret = sdrv->remove(to_spi_device(dev));
 421         dev_pm_domain_detach(dev, true);
 422
 423         return ret;
 424 }
 425
 426 static void spi_drv_shutdown(struct device *dev)
 427 {
 428         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 429
 430         sdrv->shutdown(to_spi_device(dev));
 431 }
 432
 433 /**
 434  * __spi_register_driver - register a SPI driver
 435  * @owner: owner module of the driver to register
 436  * @sdrv: the driver to register
 437  * Context: can sleep
 438  *
 439  * Return: zero on success, else a negative error code.
 440  */
 441 int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
 442 {
 443         sdrv->driver.owner = owner;
 444         sdrv->driver.bus = &spi_bus_type;
 445         if (sdrv->probe)
 446                 sdrv->driver.probe = spi_drv_probe;
 447         if (sdrv->remove)
 448                 sdrv->driver.remove = spi_drv_remove;
 449         if (sdrv->shutdown)
 450                 sdrv->driver.shutdown = spi_drv_shutdown;
 451         return driver_register(&sdrv->driver);
 452 }
 453 EXPORT_SYMBOL_GPL(__spi_register_driver);
 454
 455 /*-------------------------------------------------------------------------*/
 456
 457 /* SPI devices should normally not be created by SPI device drivers; that
 458  * would make them board-specific.  Similarly with SPI controller drivers.
 459  * Device registration normally goes into like arch/.../mach.../board-YYY.c
 460  * with other readonly (flashable) information about mainboard devices.
 461  */
 462
 463 struct boardinfo {
 464         struct list_head        list;
 465         struct spi_board_info   board_info;
 466 };
 467
 468 static LIST_HEAD(board_list);
 469 static LIST_HEAD(spi_controller_list);
 470
 471 /*
 472  * Used to protect add/del operation for board_info list and
 473  * spi_controller list, and their matching process
 474  * also used to protect object of type struct idr
 475  */
 476 static DEFINE_MUTEX(board_lock);
 477
 478 /*
 479  * Prevents addition of devices with same chip select and
 480  * addition of devices below an unregistering controller.
 481  */
 482 static DEFINE_MUTEX(spi_add_lock);
 483
 484 /**
 485  * spi_alloc_device - Allocate a new SPI device
 486  * @ctlr: Controller to which device is connected
 487  * Context: can sleep
 488  *
 489  * Allows a driver to allocate and initialize a spi_device without
 490  * registering it immediately.  This allows a driver to directly
 491  * fill the spi_device with device parameters before calling
 492  * spi_add_device() on it.
 493  *
 494  * Caller is responsible to call spi_add_device() on the returned
 495  * spi_device structure to add it to the SPI controller.  If the caller
 496  * needs to discard the spi_device without adding it, then it should
 497  * call spi_dev_put() on it.
 498  *
 499  * Return: a pointer to the new device, or NULL.
 500  */
 501 struct spi_device *spi_alloc_device(struct spi_controller *ctlr)
 502 {
 503         struct spi_device       *spi;
 504
 505         if (!spi_controller_get(ctlr))
 506                 return NULL;
 507
 508         spi = kzalloc(sizeof(*spi), GFP_KERNEL);
 509         if (!spi) {
 510                 spi_controller_put(ctlr);
 511                 return NULL;
 512         }
 513
 514         spi->master = spi->controller = ctlr;
 515         spi->dev.parent = &ctlr->dev;
 516         spi->dev.bus = &spi_bus_type;
 517         spi->dev.release = spidev_release;
 518         spi->cs_gpio = -ENOENT;
 519         spi->mode = ctlr->buswidth_override_bits;
 520
 521         spin_lock_init(&spi->statistics.lock);
 522
 523         device_initialize(&spi->dev);
 524         return spi;
 525 }
 526 EXPORT_SYMBOL_GPL(spi_alloc_device);
 527
 528 static void spi_dev_set_name(struct spi_device *spi)
 529 {
 530         struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
 531
 532         if (adev) {
 533                 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
 534                 return;
 535         }
 536
 537         dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->controller->dev),
 538                      spi->chip_select);
 539 }
 540
 541 static int spi_dev_check(struct device *dev, void *data)
 542 {
 543         struct spi_device *spi = to_spi_device(dev);
 544         struct spi_device *new_spi = data;
 545
 546         if (spi->controller == new_spi->controller &&
 547             spi->chip_select == new_spi->chip_select)
 548                 return -EBUSY;
 549         return 0;
 550 }
 551
 552 /**
 553  * spi_add_device - Add spi_device allocated with spi_alloc_device
 554  * @spi: spi_device to register
 555  *
 556  * Companion function to spi_alloc_device.  Devices allocated with
 557  * spi_alloc_device can be added onto the spi bus with this function.
 558  *
 559  * Return: 0 on success; negative errno on failure
 560  */
 561 int spi_add_device(struct spi_device *spi)
 562 {
 563         struct spi_controller *ctlr = spi->controller;
 564         struct device *dev = ctlr->dev.parent;
 565         int status;
 566
 567         /* Chipselects are numbered 0..max; validate. */
 568         if (spi->chip_select >= ctlr->num_chipselect) {
 569                 dev_err(dev, "cs%d >= max %d\n", spi->chip_select,
 570                         ctlr->num_chipselect);
 571                 return -EINVAL;
 572         }
 573
 574         /* Set the bus ID string */
 575         spi_dev_set_name(spi);
 576
 577         /* We need to make sure there's no other device with this
 578          * chipselect **BEFORE** we call setup(), else we'll trash
 579          * its configuration.  Lock against concurrent add() calls.
 580          */
 581         mutex_lock(&spi_add_lock);
 582
 583         status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
 584         if (status) {
 585                 dev_err(dev, "chipselect %d already in use\n",
 586                                 spi->chip_select);
 587                 goto done;
 588         }
 589
 590         /* Controller may unregister concurrently */
 591         if (IS_ENABLED(CONFIG_SPI_DYNAMIC) &&
 592             !device_is_registered(&ctlr->dev)) {
 593                 status = -ENODEV;
 594                 goto done;
 595         }
 596
 597         /* Descriptors take precedence */
 598         if (ctlr->cs_gpiods)
 599                 spi->cs_gpiod = ctlr->cs_gpiods[spi->chip_select];
 600         else if (ctlr->cs_gpios)
 601                 spi->cs_gpio = ctlr->cs_gpios[spi->chip_select];
 602
 603         /* Drivers may modify this initial i/o setup, but will
 604          * normally rely on the device being setup.  Devices
 605          * using SPI_CS_HIGH can't coexist well otherwise...
 606          */
 607         status = spi_setup(spi);
 608         if (status < 0) {
 609                 dev_err(dev, "can't setup %s, status %d\n",
 610                                 dev_name(&spi->dev), status);
 611                 goto done;
 612         }
 613
 614         /* Device may be bound to an active driver when this returns */
 615         status = device_add(&spi->dev);
 616         if (status < 0)
 617                 dev_err(dev, "can't add %s, status %d\n",
 618                                 dev_name(&spi->dev), status);
 619         else
 620                 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
 621
 622 done:
 623         mutex_unlock(&spi_add_lock);
 624         return status;
 625 }
 626 EXPORT_SYMBOL_GPL(spi_add_device);
 627
 628 /**
 629  * spi_new_device - instantiate one new SPI device
 630  * @ctlr: Controller to which device is connected
 631  * @chip: Describes the SPI device
 632  * Context: can sleep
 633  *
 634  * On typical mainboards, this is purely internal; and it's not needed
 635  * after board init creates the hard-wired devices.  Some development
 636  * platforms may not be able to use spi_register_board_info though, and
 637  * this is exported so that for example a USB or parport based adapter
 638  * driver could add devices (which it would learn about out-of-band).
 639  *
 640  * Return: the new device, or NULL.
 641  */
 642 struct spi_device *spi_new_device(struct spi_controller *ctlr,
 643                                   struct spi_board_info *chip)
 644 {
 645         struct spi_device       *proxy;
 646         int                     status;
 647
 648         /* NOTE:  caller did any chip->bus_num checks necessary.
 649          *
 650          * Also, unless we change the return value convention to use
 651          * error-or-pointer (not NULL-or-pointer), troubleshootability
 652          * suggests syslogged diagnostics are best here (ugh).
 653          */
 654
 655         proxy = spi_alloc_device(ctlr);
 656         if (!proxy)
 657                 return NULL;
 658
 659         WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
 660
 661         proxy->chip_select = chip->chip_select;
 662         proxy->max_speed_hz = chip->max_speed_hz;
 663         proxy->mode = chip->mode;
 664         proxy->irq = chip->irq;
 665         strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
 666         proxy->dev.platform_data = (void *) chip->platform_data;
 667         proxy->controller_data = chip->controller_data;
 668         proxy->controller_state = NULL;
 669
 670         if (chip->properties) {
 671                 status = device_add_properties(&proxy->dev, chip->properties);
 672                 if (status) {
 673                         dev_err(&ctlr->dev,
 674                                 "failed to add properties to '%s': %d\n",
 675                                 chip->modalias, status);
 676                         goto err_dev_put;
 677                 }
 678         }
 679
 680         status = spi_add_device(proxy);
 681         if (status < 0)
 682                 goto err_remove_props;
 683
 684         return proxy;
 685
 686 err_remove_props:
 687         if (chip->properties)
 688                 device_remove_properties(&proxy->dev);
 689 err_dev_put:
 690         spi_dev_put(proxy);
 691         return NULL;
 692 }
 693 EXPORT_SYMBOL_GPL(spi_new_device);
 694
 695 /**
 696  * spi_unregister_device - unregister a single SPI device
 697  * @spi: spi_device to unregister
 698  *
 699  * Start making the passed SPI device vanish. Normally this would be handled
 700  * by spi_unregister_controller().
 701  */
 702 void spi_unregister_device(struct spi_device *spi)
 703 {
 704         if (!spi)
 705                 return;
 706
 707         if (spi->dev.of_node) {
 708                 of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
 709                 of_node_put(spi->dev.of_node);
 710         }
 711         if (ACPI_COMPANION(&spi->dev))
 712                 acpi_device_clear_enumerated(ACPI_COMPANION(&spi->dev));
 713         device_unregister(&spi->dev);
 714 }
 715 EXPORT_SYMBOL_GPL(spi_unregister_device);
 716
 717 static void spi_match_controller_to_boardinfo(struct spi_controller *ctlr,
 718                                               struct spi_board_info *bi)
 719 {
 720         struct spi_device *dev;
 721
 722         if (ctlr->bus_num != bi->bus_num)
 723                 return;
 724
 725         dev = spi_new_device(ctlr, bi);
 726         if (!dev)
 727                 dev_err(ctlr->dev.parent, "can't create new device for %s\n",
 728                         bi->modalias);
 729 }
 730
 731 /**
 732  * spi_register_board_info - register SPI devices for a given board
 733  * @info: array of chip descriptors
 734  * @n: how many descriptors are provided
 735  * Context: can sleep
 736  *
 737  * Board-specific early init code calls this (probably during arch_initcall)
 738  * with segments of the SPI device table.  Any device nodes are created later,
 739  * after the relevant parent SPI controller (bus_num) is defined.  We keep
 740  * this table of devices forever, so that reloading a controller driver will
 741  * not make Linux forget about these hard-wired devices.
 742  *
 743  * Other code can also call this, e.g. a particular add-on board might provide
 744  * SPI devices through its expansion connector, so code initializing that board
 745  * would naturally declare its SPI devices.
 746  *
 747  * The board info passed can safely be __initdata ... but be careful of
 748  * any embedded pointers (platform_data, etc), they're copied as-is.
 749  * Device properties are deep-copied though.
 750  *
 751  * Return: zero on success, else a negative error code.
 752  */
 753 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
 754 {
 755         struct boardinfo *bi;
 756         int i;
 757
 758         if (!n)
 759                 return 0;
 760
 761         bi = kcalloc(n, sizeof(*bi), GFP_KERNEL);
 762         if (!bi)
 763                 return -ENOMEM;
 764
 765         for (i = 0; i < n; i++, bi++, info++) {
 766                 struct spi_controller *ctlr;
 767
 768                 memcpy(&bi->board_info, info, sizeof(*info));
 769                 if (info->properties) {
 770                         bi->board_info.properties =
 771                                         property_entries_dup(info->properties);
 772                         if (IS_ERR(bi->board_info.properties))
 773                                 return PTR_ERR(bi->board_info.properties);
 774                 }
 775
 776                 mutex_lock(&board_lock);
 777                 list_add_tail(&bi->list, &board_list);
 778                 list_for_each_entry(ctlr, &spi_controller_list, list)
 779                         spi_match_controller_to_boardinfo(ctlr,
 780                                                           &bi->board_info);
 781                 mutex_unlock(&board_lock);
 782         }
 783
 784         return 0;
 785 }
 786
 787 /*-------------------------------------------------------------------------*/
 788
 789 static void spi_set_cs(struct spi_device *spi, bool enable)
 790 {
 791         bool enable1 = enable;
 792
 793         /*
 794          * Avoid calling into the driver (or doing delays) if the chip select
 795          * isn't actually changing from the last time this was called.
 796          */
 797         if ((spi->controller->last_cs_enable == enable) &&
 798             (spi->controller->last_cs_mode_high == (spi->mode & SPI_CS_HIGH)))
 799                 return;
 800
 801         spi->controller->last_cs_enable = enable;
 802         spi->controller->last_cs_mode_high = spi->mode & SPI_CS_HIGH;
 803
 804         if (!spi->controller->set_cs_timing) {
 805                 if (enable1)
 806                         spi_delay_exec(&spi->controller->cs_setup, NULL);
 807                 else
 808                         spi_delay_exec(&spi->controller->cs_hold, NULL);
 809         }
 810
 811         if (spi->mode & SPI_CS_HIGH)
 812                 enable = !enable;
 813
 814         if (spi->cs_gpiod || gpio_is_valid(spi->cs_gpio)) {
 815                 if (!(spi->mode & SPI_NO_CS)) {
 816                         if (spi->cs_gpiod)
 817                                 /* polarity handled by gpiolib */
 818                                 gpiod_set_value_cansleep(spi->cs_gpiod,
 819                                                          enable1);
 820                         else
 821                                 /*
 822                                  * invert the enable line, as active low is
 823                                  * default for SPI.
 824                                  */
 825                                 gpio_set_value_cansleep(spi->cs_gpio, !enable);
 826                 }
 827                 /* Some SPI masters need both GPIO CS & slave_select */
 828                 if ((spi->controller->flags & SPI_MASTER_GPIO_SS) &&
 829                     spi->controller->set_cs)
 830                         spi->controller->set_cs(spi, !enable);
 831         } else if (spi->controller->set_cs) {
 832                 spi->controller->set_cs(spi, !enable);
 833         }
 834
 835         if (!spi->controller->set_cs_timing) {
 836                 if (!enable1)
 837                         spi_delay_exec(&spi->controller->cs_inactive, NULL);
 838         }
 839 }
 840
 841 #ifdef CONFIG_HAS_DMA
 842 int spi_map_buf(struct spi_controller *ctlr, struct device *dev,
 843                 struct sg_table *sgt, void *buf, size_t len,
 844                 enum dma_data_direction dir)
 845 {
 846         const bool vmalloced_buf = is_vmalloc_addr(buf);
 847         unsigned int max_seg_size = dma_get_max_seg_size(dev);
 848 #ifdef CONFIG_HIGHMEM
 849         const bool kmap_buf = ((unsigned long)buf >= PKMAP_BASE &&
 850                                 (unsigned long)buf < (PKMAP_BASE +
 851                                         (LAST_PKMAP * PAGE_SIZE)));
 852 #else
 853         const bool kmap_buf = false;
 854 #endif
 855         int desc_len;
 856         int sgs;
 857         struct page *vm_page;
 858         struct scatterlist *sg;
 859         void *sg_buf;
 860         size_t min;
 861         int i, ret;
 862
 863         if (vmalloced_buf || kmap_buf) {
 864                 desc_len = min_t(int, max_seg_size, PAGE_SIZE);
 865                 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
 866         } else if (virt_addr_valid(buf)) {
 867                 desc_len = min_t(int, max_seg_size, ctlr->max_dma_len);
 868                 sgs = DIV_ROUND_UP(len, desc_len);
 869         } else {
 870                 return -EINVAL;
 871         }
 872
 873         ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
 874         if (ret != 0)
 875                 return ret;
 876
 877         sg = &sgt->sgl[0];
 878         for (i = 0; i < sgs; i++) {
 879
 880                 if (vmalloced_buf || kmap_buf) {
 881                         /*
 882                          * Next scatterlist entry size is the minimum between
 883                          * the desc_len and the remaining buffer length that
 884                          * fits in a page.
 885                          */
 886                         min = min_t(size_t, desc_len,
 887                                     min_t(size_t, len,
 888                                           PAGE_SIZE - offset_in_page(buf)));
 889                         if (vmalloced_buf)
 890                                 vm_page = vmalloc_to_page(buf);
 891                         else
 892                                 vm_page = kmap_to_page(buf);
 893                         if (!vm_page) {
 894                                 sg_free_table(sgt);
 895                                 return -ENOMEM;
 896                         }
 897                         sg_set_page(sg, vm_page,
 898                                     min, offset_in_page(buf));
 899                 } else {
 900                         min = min_t(size_t, len, desc_len);
 901                         sg_buf = buf;
 902                         sg_set_buf(sg, sg_buf, min);
 903                 }
 904
 905                 buf += min;
 906                 len -= min;
 907                 sg = sg_next(sg);
 908         }
 909
 910         ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
 911         if (!ret)
 912                 ret = -ENOMEM;
 913         if (ret < 0) {
 914                 sg_free_table(sgt);
 915                 return ret;
 916         }
 917
 918         sgt->nents = ret;
 919
 920         return 0;
 921 }
 922
 923 void spi_unmap_buf(struct spi_controller *ctlr, struct device *dev,
 924                    struct sg_table *sgt, enum dma_data_direction dir)
 925 {
 926         if (sgt->orig_nents) {
 927                 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
 928                 sg_free_table(sgt);
 929         }
 930 }
 931
 932 static int __spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
 933 {
 934         struct device *tx_dev, *rx_dev;
 935         struct spi_transfer *xfer;
 936         int ret;
 937
 938         if (!ctlr->can_dma)
 939                 return 0;
 940
 941         if (ctlr->dma_tx)
 942                 tx_dev = ctlr->dma_tx->device->dev;
 943         else
 944                 tx_dev = ctlr->dev.parent;
 945
 946         if (ctlr->dma_rx)
 947                 rx_dev = ctlr->dma_rx->device->dev;
 948         else
 949                 rx_dev = ctlr->dev.parent;
 950
 951         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 952                 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
 953                         continue;
 954
 955                 if (xfer->tx_buf != NULL) {
 956                         ret = spi_map_buf(ctlr, tx_dev, &xfer->tx_sg,
 957                                           (void *)xfer->tx_buf, xfer->len,
 958                                           DMA_TO_DEVICE);
 959                         if (ret != 0)
 960                                 return ret;
 961                 }
 962
 963                 if (xfer->rx_buf != NULL) {
 964                         ret = spi_map_buf(ctlr, rx_dev, &xfer->rx_sg,
 965                                           xfer->rx_buf, xfer->len,
 966                                           DMA_FROM_DEVICE);
 967                         if (ret != 0) {
 968                                 spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg,
 969                                               DMA_TO_DEVICE);
 970                                 return ret;
 971                         }
 972                 }
 973         }
 974
 975         ctlr->cur_msg_mapped = true;
 976
 977         return 0;
 978 }
 979
 980 static int __spi_unmap_msg(struct spi_controller *ctlr, struct spi_message *msg)
 981 {
 982         struct spi_transfer *xfer;
 983         struct device *tx_dev, *rx_dev;
 984
 985         if (!ctlr->cur_msg_mapped || !ctlr->can_dma)
 986                 return 0;
 987
 988         if (ctlr->dma_tx)
 989                 tx_dev = ctlr->dma_tx->device->dev;
 990         else
 991                 tx_dev = ctlr->dev.parent;
 992
 993         if (ctlr->dma_rx)
 994                 rx_dev = ctlr->dma_rx->device->dev;
 995         else
 996                 rx_dev = ctlr->dev.parent;
 997
 998         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 999                 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
1000                         continue;
1001
1002                 spi_unmap_buf(ctlr, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
1003                 spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
1004         }
1005
1006         ctlr->cur_msg_mapped = false;
1007
1008         return 0;
1009 }
1010 #else /* !CONFIG_HAS_DMA */
1011 static inline int __spi_map_msg(struct spi_controller *ctlr,
1012                                 struct spi_message *msg)
1013 {
1014         return 0;
1015 }
1016
1017 static inline int __spi_unmap_msg(struct spi_controller *ctlr,
1018                                   struct spi_message *msg)
1019 {
1020         return 0;
1021 }
1022 #endif /* !CONFIG_HAS_DMA */
1023
1024 static inline int spi_unmap_msg(struct spi_controller *ctlr,
1025                                 struct spi_message *msg)
1026 {
1027         struct spi_transfer *xfer;
1028
1029         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1030                 /*
1031                  * Restore the original value of tx_buf or rx_buf if they are
1032                  * NULL.
1033                  */
1034                 if (xfer->tx_buf == ctlr->dummy_tx)
1035                         xfer->tx_buf = NULL;
1036                 if (xfer->rx_buf == ctlr->dummy_rx)
1037                         xfer->rx_buf = NULL;
1038         }
1039
1040         return __spi_unmap_msg(ctlr, msg);
1041 }
1042
1043 static int spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
1044 {
1045         struct spi_transfer *xfer;
1046         void *tmp;
1047         unsigned int max_tx, max_rx;
1048
1049         if ((ctlr->flags & (SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX))
1050                 && !(msg->spi->mode & SPI_3WIRE)) {
1051                 max_tx = 0;
1052                 max_rx = 0;
1053
1054                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1055                         if ((ctlr->flags & SPI_CONTROLLER_MUST_TX) &&
1056                             !xfer->tx_buf)
1057                                 max_tx = max(xfer->len, max_tx);
1058                         if ((ctlr->flags & SPI_CONTROLLER_MUST_RX) &&
1059                             !xfer->rx_buf)
1060                                 max_rx = max(xfer->len, max_rx);
1061                 }
1062
1063                 if (max_tx) {
1064                         tmp = krealloc(ctlr->dummy_tx, max_tx,
1065                                        GFP_KERNEL | GFP_DMA);
1066                         if (!tmp)
1067                                 return -ENOMEM;
1068                         ctlr->dummy_tx = tmp;
1069                         memset(tmp, 0, max_tx);
1070                 }
1071
1072                 if (max_rx) {
1073                         tmp = krealloc(ctlr->dummy_rx, max_rx,
1074                                        GFP_KERNEL | GFP_DMA);
1075                         if (!tmp)
1076                                 return -ENOMEM;
1077                         ctlr->dummy_rx = tmp;
1078                 }
1079
1080                 if (max_tx || max_rx) {
1081                         list_for_each_entry(xfer, &msg->transfers,
1082                                             transfer_list) {
1083                                 if (!xfer->len)
1084                                         continue;
1085                                 if (!xfer->tx_buf)
1086                                         xfer->tx_buf = ctlr->dummy_tx;
1087                                 if (!xfer->rx_buf)
1088                                         xfer->rx_buf = ctlr->dummy_rx;
1089                         }
1090                 }
1091         }
1092
1093         return __spi_map_msg(ctlr, msg);
1094 }
1095
1096 static int spi_transfer_wait(struct spi_controller *ctlr,
1097                              struct spi_message *msg,
1098                              struct spi_transfer *xfer)
1099 {
1100         struct spi_statistics *statm = &ctlr->statistics;
1101         struct spi_statistics *stats = &msg->spi->statistics;
1102         unsigned long long ms;
1103
1104         if (spi_controller_is_slave(ctlr)) {
1105                 if (wait_for_completion_interruptible(&ctlr->xfer_completion)) {
1106                         dev_dbg(&msg->spi->dev, "SPI transfer interrupted\n");
1107                         return -EINTR;
1108                 }
1109         } else {
1110                 ms = 8LL * 1000LL * xfer->len;
1111                 do_div(ms, xfer->speed_hz);
1112                 ms += ms + 200; /* some tolerance */
1113
1114                 if (ms > UINT_MAX)
1115                         ms = UINT_MAX;
1116
1117                 ms = wait_for_completion_timeout(&ctlr->xfer_completion,
1118                                                  msecs_to_jiffies(ms));
1119
1120                 if (ms == 0) {
1121                         SPI_STATISTICS_INCREMENT_FIELD(statm, timedout);
1122                         SPI_STATISTICS_INCREMENT_FIELD(stats, timedout);
1123                         dev_err(&msg->spi->dev,
1124                                 "SPI transfer timed out\n");
1125                         return -ETIMEDOUT;
1126                 }
1127         }
1128
1129         return 0;
1130 }
1131
1132 static void _spi_transfer_delay_ns(u32 ns)
1133 {
1134         if (!ns)
1135                 return;
1136         if (ns <= 1000) {
1137                 ndelay(ns);
1138         } else {
1139                 u32 us = DIV_ROUND_UP(ns, 1000);
1140
1141                 if (us <= 10)
1142                         udelay(us);
1143                 else
1144                         usleep_range(us, us + DIV_ROUND_UP(us, 10));
1145         }
1146 }
1147
1148 int spi_delay_to_ns(struct spi_delay *_delay, struct spi_transfer *xfer)
1149 {
1150         u32 delay = _delay->value;
1151         u32 unit = _delay->unit;
1152         u32 hz;
1153
1154         if (!delay)
1155                 return 0;
1156
1157         switch (unit) {
1158         case SPI_DELAY_UNIT_USECS:
1159                 delay *= 1000;
1160                 break;
1161         case SPI_DELAY_UNIT_NSECS: /* nothing to do here */
1162                 break;
1163         case SPI_DELAY_UNIT_SCK:
1164                 /* clock cycles need to be obtained from spi_transfer */
1165                 if (!xfer)
1166                         return -EINVAL;
1167                 /* if there is no effective speed know, then approximate
1168                  * by underestimating with half the requested hz
1169                  */
1170                 hz = xfer->effective_speed_hz ?: xfer->speed_hz / 2;
1171                 if (!hz)
1172                         return -EINVAL;
1173                 delay *= DIV_ROUND_UP(1000000000, hz);
1174                 break;
1175         default:
1176                 return -EINVAL;
1177         }
1178
1179         return delay;
1180 }
1181 EXPORT_SYMBOL_GPL(spi_delay_to_ns);
1182
1183 int spi_delay_exec(struct spi_delay *_delay, struct spi_transfer *xfer)
1184 {
1185         int delay;
1186
1187         might_sleep();
1188
1189         if (!_delay)
1190                 return -EINVAL;
1191
1192         delay = spi_delay_to_ns(_delay, xfer);
1193         if (delay < 0)
1194                 return delay;
1195
1196         _spi_transfer_delay_ns(delay);
1197
1198         return 0;
1199 }
1200 EXPORT_SYMBOL_GPL(spi_delay_exec);
1201
1202 static void _spi_transfer_cs_change_delay(struct spi_message *msg,
1203                                           struct spi_transfer *xfer)
1204 {
1205         u32 delay = xfer->cs_change_delay.value;
1206         u32 unit = xfer->cs_change_delay.unit;
1207         int ret;
1208
1209         /* return early on "fast" mode - for everything but USECS */
1210         if (!delay) {
1211                 if (unit == SPI_DELAY_UNIT_USECS)
1212                         _spi_transfer_delay_ns(10000);
1213                 return;
1214         }
1215
1216         ret = spi_delay_exec(&xfer->cs_change_delay, xfer);
1217         if (ret) {
1218                 dev_err_once(&msg->spi->dev,
1219                              "Use of unsupported delay unit %i, using default of 10us\n",
1220                              unit);
1221                 _spi_transfer_delay_ns(10000);
1222         }
1223 }
1224
1225 /*
1226  * spi_transfer_one_message - Default implementation of transfer_one_message()
1227  *
1228  * This is a standard implementation of transfer_one_message() for
1229  * drivers which implement a transfer_one() operation.  It provides
1230  * standard handling of delays and chip select management.
1231  */
1232 static int spi_transfer_one_message(struct spi_controller *ctlr,
1233                                     struct spi_message *msg)
1234 {
1235         struct spi_transfer *xfer;
1236         bool keep_cs = false;
1237         int ret = 0;
1238         struct spi_statistics *statm = &ctlr->statistics;
1239         struct spi_statistics *stats = &msg->spi->statistics;
1240
1241         spi_set_cs(msg->spi, true);
1242
1243         SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
1244         SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
1245
1246         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1247                 trace_spi_transfer_start(msg, xfer);
1248
1249                 spi_statistics_add_transfer_stats(statm, xfer, ctlr);
1250                 spi_statistics_add_transfer_stats(stats, xfer, ctlr);
1251
1252                 if (!ctlr->ptp_sts_supported) {
1253                         xfer->ptp_sts_word_pre = 0;
1254                         ptp_read_system_prets(xfer->ptp_sts);
1255                 }
1256
1257                 if (xfer->tx_buf || xfer->rx_buf) {
1258                         reinit_completion(&ctlr->xfer_completion);
1259
1260 fallback_pio:
1261                         ret = ctlr->transfer_one(ctlr, msg->spi, xfer);
1262                         if (ret < 0) {
1263                                 if (ctlr->cur_msg_mapped &&
1264                                    (xfer->error & SPI_TRANS_FAIL_NO_START)) {
1265                                         __spi_unmap_msg(ctlr, msg);
1266                                         ctlr->fallback = true;
1267                                         xfer->error &= ~SPI_TRANS_FAIL_NO_START;
1268                                         goto fallback_pio;
1269                                 }
1270
1271                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
1272                                                                errors);
1273                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
1274                                                                errors);
1275                                 dev_err(&msg->spi->dev,
1276                                         "SPI transfer failed: %d\n", ret);
1277                                 goto out;
1278                         }
1279
1280                         if (ret > 0) {
1281                                 ret = spi_transfer_wait(ctlr, msg, xfer);
1282                                 if (ret < 0)
1283                                         msg->status = ret;
1284                         }
1285                 } else {
1286                         if (xfer->len)
1287                                 dev_err(&msg->spi->dev,
1288                                         "Bufferless transfer has length %u\n",
1289                                         xfer->len);
1290                 }
1291
1292                 if (!ctlr->ptp_sts_supported) {
1293                         ptp_read_system_postts(xfer->ptp_sts);
1294                         xfer->ptp_sts_word_post = xfer->len;
1295                 }
1296
1297                 trace_spi_transfer_stop(msg, xfer);
1298
1299                 if (msg->status != -EINPROGRESS)
1300                         goto out;
1301
1302                 spi_transfer_delay_exec(xfer);
1303
1304                 if (xfer->cs_change) {
1305                         if (list_is_last(&xfer->transfer_list,
1306                                          &msg->transfers)) {
1307                                 keep_cs = true;
1308                         } else {
1309                                 spi_set_cs(msg->spi, false);
1310                                 _spi_transfer_cs_change_delay(msg, xfer);
1311                                 spi_set_cs(msg->spi, true);
1312                         }
1313                 }
1314
1315                 msg->actual_length += xfer->len;
1316         }
1317
1318 out:
1319         if (ret != 0 || !keep_cs)
1320                 spi_set_cs(msg->spi, false);
1321
1322         if (msg->status == -EINPROGRESS)
1323                 msg->status = ret;
1324
1325         if (msg->status && ctlr->handle_err)
1326                 ctlr->handle_err(ctlr, msg);
1327
1328         spi_finalize_current_message(ctlr);
1329
1330         return ret;
1331 }
1332
1333 /**
1334  * spi_finalize_current_transfer - report completion of a transfer
1335  * @ctlr: the controller reporting completion
1336  *
1337  * Called by SPI drivers using the core transfer_one_message()
1338  * implementation to notify it that the current interrupt driven
1339  * transfer has finished and the next one may be scheduled.
1340  */
1341 void spi_finalize_current_transfer(struct spi_controller *ctlr)
1342 {
1343         complete(&ctlr->xfer_completion);
1344 }
1345 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1346
1347 static void spi_idle_runtime_pm(struct spi_controller *ctlr)
1348 {
1349         if (ctlr->auto_runtime_pm) {
1350                 pm_runtime_mark_last_busy(ctlr->dev.parent);
1351                 pm_runtime_put_autosuspend(ctlr->dev.parent);
1352         }
1353 }
1354
1355 /**
1356  * __spi_pump_messages - function which processes spi message queue
1357  * @ctlr: controller to process queue for
1358  * @in_kthread: true if we are in the context of the message pump thread
1359  *
1360  * This function checks if there is any spi message in the queue that
1361  * needs processing and if so call out to the driver to initialize hardware
1362  * and transfer each message.
1363  *
1364  * Note that it is called both from the kthread itself and also from
1365  * inside spi_sync(); the queue extraction handling at the top of the
1366  * function should deal with this safely.
1367  */
1368 static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread)
1369 {
1370         struct spi_transfer *xfer;
1371         struct spi_message *msg;
1372         bool was_busy = false;
1373         unsigned long flags;
1374         int ret;
1375
1376         /* Lock queue */
1377         spin_lock_irqsave(&ctlr->queue_lock, flags);
1378
1379         /* Make sure we are not already running a message */
1380         if (ctlr->cur_msg) {
1381                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1382                 return;
1383         }
1384
1385         /* If another context is idling the device then defer */
1386         if (ctlr->idling) {
1387                 kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1388                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1389                 return;
1390         }
1391
1392         /* Check if the queue is idle */
1393         if (list_empty(&ctlr->queue) || !ctlr->running) {
1394                 if (!ctlr->busy) {
1395                         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1396                         return;
1397                 }
1398
1399                 /* Defer any non-atomic teardown to the thread */
1400                 if (!in_kthread) {
1401                         if (!ctlr->dummy_rx && !ctlr->dummy_tx &&
1402                             !ctlr->unprepare_transfer_hardware) {
1403                                 spi_idle_runtime_pm(ctlr);
1404                                 ctlr->busy = false;
1405                                 trace_spi_controller_idle(ctlr);
1406                         } else {
1407                                 kthread_queue_work(ctlr->kworker,
1408                                                    &ctlr->pump_messages);
1409                         }
1410                         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1411                         return;
1412                 }
1413
1414                 ctlr->busy = false;
1415                 ctlr->idling = true;
1416                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1417
1418                 kfree(ctlr->dummy_rx);
1419                 ctlr->dummy_rx = NULL;
1420                 kfree(ctlr->dummy_tx);
1421                 ctlr->dummy_tx = NULL;
1422                 if (ctlr->unprepare_transfer_hardware &&
1423                     ctlr->unprepare_transfer_hardware(ctlr))
1424                         dev_err(&ctlr->dev,
1425                                 "failed to unprepare transfer hardware\n");
1426                 spi_idle_runtime_pm(ctlr);
1427                 trace_spi_controller_idle(ctlr);
1428
1429                 spin_lock_irqsave(&ctlr->queue_lock, flags);
1430                 ctlr->idling = false;
1431                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1432                 return;
1433         }
1434
1435         /* Extract head of queue */
1436         msg = list_first_entry(&ctlr->queue, struct spi_message, queue);
1437         ctlr->cur_msg = msg;
1438
1439         list_del_init(&msg->queue);
1440         if (ctlr->busy)
1441                 was_busy = true;
1442         else
1443                 ctlr->busy = true;
1444         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1445
1446         mutex_lock(&ctlr->io_mutex);
1447
1448         if (!was_busy && ctlr->auto_runtime_pm) {
1449                 ret = pm_runtime_get_sync(ctlr->dev.parent);
1450                 if (ret < 0) {
1451                         pm_runtime_put_noidle(ctlr->dev.parent);
1452                         dev_err(&ctlr->dev, "Failed to power device: %d\n",
1453                                 ret);
1454                         mutex_unlock(&ctlr->io_mutex);
1455                         return;
1456                 }
1457         }
1458
1459         if (!was_busy)
1460                 trace_spi_controller_busy(ctlr);
1461
1462         if (!was_busy && ctlr->prepare_transfer_hardware) {
1463                 ret = ctlr->prepare_transfer_hardware(ctlr);
1464                 if (ret) {
1465                         dev_err(&ctlr->dev,
1466                                 "failed to prepare transfer hardware: %d\n",
1467                                 ret);
1468
1469                         if (ctlr->auto_runtime_pm)
1470                                 pm_runtime_put(ctlr->dev.parent);
1471
1472                         msg->status = ret;
1473                         spi_finalize_current_message(ctlr);
1474
1475                         mutex_unlock(&ctlr->io_mutex);
1476                         return;
1477                 }
1478         }
1479
1480         trace_spi_message_start(msg);
1481
1482         if (ctlr->prepare_message) {
1483                 ret = ctlr->prepare_message(ctlr, msg);
1484                 if (ret) {
1485                         dev_err(&ctlr->dev, "failed to prepare message: %d\n",
1486                                 ret);
1487                         msg->status = ret;
1488                         spi_finalize_current_message(ctlr);
1489                         goto out;
1490                 }
1491                 ctlr->cur_msg_prepared = true;
1492         }
1493
1494         ret = spi_map_msg(ctlr, msg);
1495         if (ret) {
1496                 msg->status = ret;
1497                 spi_finalize_current_message(ctlr);
1498                 goto out;
1499         }
1500
1501         if (!ctlr->ptp_sts_supported && !ctlr->transfer_one) {
1502                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1503                         xfer->ptp_sts_word_pre = 0;
1504                         ptp_read_system_prets(xfer->ptp_sts);
1505                 }
1506         }
1507
1508         ret = ctlr->transfer_one_message(ctlr, msg);
1509         if (ret) {
1510                 dev_err(&ctlr->dev,
1511                         "failed to transfer one message from queue\n");
1512                 goto out;
1513         }
1514
1515 out:
1516         mutex_unlock(&ctlr->io_mutex);
1517
1518         /* Prod the scheduler in case transfer_one() was busy waiting */
1519         if (!ret)
1520                 cond_resched();
1521 }
1522
1523 /**
1524  * spi_pump_messages - kthread work function which processes spi message queue
1525  * @work: pointer to kthread work struct contained in the controller struct
1526  */
1527 static void spi_pump_messages(struct kthread_work *work)
1528 {
1529         struct spi_controller *ctlr =
1530                 container_of(work, struct spi_controller, pump_messages);
1531
1532         __spi_pump_messages(ctlr, true);
1533 }
1534
1535 /**
1536  * spi_take_timestamp_pre - helper for drivers to collect the beginning of the
1537  *                          TX timestamp for the requested byte from the SPI
1538  *                          transfer. The frequency with which this function
1539  *                          must be called (once per word, once for the whole
1540  *                          transfer, once per batch of words etc) is arbitrary
1541  *                          as long as the @tx buffer offset is greater than or
1542  *                          equal to the requested byte at the time of the
1543  *                          call. The timestamp is only taken once, at the
1544  *                          first such call. It is assumed that the driver
1545  *                          advances its @tx buffer pointer monotonically.
1546  * @ctlr: Pointer to the spi_controller structure of the driver
1547  * @xfer: Pointer to the transfer being timestamped
1548  * @progress: How many words (not bytes) have been transferred so far
1549  * @irqs_off: If true, will disable IRQs and preemption for the duration of the
1550  *            transfer, for less jitter in time measurement. Only compatible
1551  *            with PIO drivers. If true, must follow up with
1552  *            spi_take_timestamp_post or otherwise system will crash.
1553  *            WARNING: for fully predictable results, the CPU frequency must
1554  *            also be under control (governor).
1555  */
1556 void spi_take_timestamp_pre(struct spi_controller *ctlr,
1557                             struct spi_transfer *xfer,
1558                             size_t progress, bool irqs_off)
1559 {
1560         if (!xfer->ptp_sts)
1561                 return;
1562
1563         if (xfer->timestamped)
1564                 return;
1565
1566         if (progress > xfer->ptp_sts_word_pre)
1567                 return;
1568
1569         /* Capture the resolution of the timestamp */
1570         xfer->ptp_sts_word_pre = progress;
1571
1572         if (irqs_off) {
1573                 local_irq_save(ctlr->irq_flags);
1574                 preempt_disable();
1575         }
1576
1577         ptp_read_system_prets(xfer->ptp_sts);
1578 }
1579 EXPORT_SYMBOL_GPL(spi_take_timestamp_pre);
1580
1581 /**
1582  * spi_take_timestamp_post - helper for drivers to collect the end of the
1583  *                           TX timestamp for the requested byte from the SPI
1584  *                           transfer. Can be called with an arbitrary
1585  *                           frequency: only the first call where @tx exceeds
1586  *                           or is equal to the requested word will be
1587  *                           timestamped.
1588  * @ctlr: Pointer to the spi_controller structure of the driver
1589  * @xfer: Pointer to the transfer being timestamped
1590  * @progress: How many words (not bytes) have been transferred so far
1591  * @irqs_off: If true, will re-enable IRQs and preemption for the local CPU.
1592  */
1593 void spi_take_timestamp_post(struct spi_controller *ctlr,
1594                              struct spi_transfer *xfer,
1595                              size_t progress, bool irqs_off)
1596 {
1597         if (!xfer->ptp_sts)
1598                 return;
1599
1600         if (xfer->timestamped)
1601                 return;
1602
1603         if (progress < xfer->ptp_sts_word_post)
1604                 return;
1605
1606         ptp_read_system_postts(xfer->ptp_sts);
1607
1608         if (irqs_off) {
1609                 local_irq_restore(ctlr->irq_flags);
1610                 preempt_enable();
1611         }
1612
1613         /* Capture the resolution of the timestamp */
1614         xfer->ptp_sts_word_post = progress;
1615
1616         xfer->timestamped = true;
1617 }
1618 EXPORT_SYMBOL_GPL(spi_take_timestamp_post);
1619
1620 /**
1621  * spi_set_thread_rt - set the controller to pump at realtime priority
1622  * @ctlr: controller to boost priority of
1623  *
1624  * This can be called because the controller requested realtime priority
1625  * (by setting the ->rt value before calling spi_register_controller()) or
1626  * because a device on the bus said that its transfers needed realtime
1627  * priority.
1628  *
1629  * NOTE: at the moment if any device on a bus says it needs realtime then
1630  * the thread will be at realtime priority for all transfers on that
1631  * controller.  If this eventually becomes a problem we may see if we can
1632  * find a way to boost the priority only temporarily during relevant
1633  * transfers.
1634  */
1635 static void spi_set_thread_rt(struct spi_controller *ctlr)
1636 {
1637         dev_info(&ctlr->dev,
1638                 "will run message pump with realtime priority\n");
1639         sched_set_fifo(ctlr->kworker->task);
1640 }
1641
1642 static int spi_init_queue(struct spi_controller *ctlr)
1643 {
1644         ctlr->running = false;
1645         ctlr->busy = false;
1646
1647         ctlr->kworker = kthread_create_worker(0, dev_name(&ctlr->dev));
1648         if (IS_ERR(ctlr->kworker)) {
1649                 dev_err(&ctlr->dev, "failed to create message pump kworker\n");
1650                 return PTR_ERR(ctlr->kworker);
1651         }
1652
1653         kthread_init_work(&ctlr->pump_messages, spi_pump_messages);
1654
1655         /*
1656          * Controller config will indicate if this controller should run the
1657          * message pump with high (realtime) priority to reduce the transfer
1658          * latency on the bus by minimising the delay between a transfer
1659          * request and the scheduling of the message pump thread. Without this
1660          * setting the message pump thread will remain at default priority.
1661          */
1662         if (ctlr->rt)
1663                 spi_set_thread_rt(ctlr);
1664
1665         return 0;
1666 }
1667
1668 /**
1669  * spi_get_next_queued_message() - called by driver to check for queued
1670  * messages
1671  * @ctlr: the controller to check for queued messages
1672  *
1673  * If there are more messages in the queue, the next message is returned from
1674  * this call.
1675  *
1676  * Return: the next message in the queue, else NULL if the queue is empty.
1677  */
1678 struct spi_message *spi_get_next_queued_message(struct spi_controller *ctlr)
1679 {
1680         struct spi_message *next;
1681         unsigned long flags;
1682
1683         /* get a pointer to the next message, if any */
1684         spin_lock_irqsave(&ctlr->queue_lock, flags);
1685         next = list_first_entry_or_null(&ctlr->queue, struct spi_message,
1686                                         queue);
1687         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1688
1689         return next;
1690 }
1691 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1692
1693 /**
1694  * spi_finalize_current_message() - the current message is complete
1695  * @ctlr: the controller to return the message to
1696  *
1697  * Called by the driver to notify the core that the message in the front of the
1698  * queue is complete and can be removed from the queue.
1699  */
1700 void spi_finalize_current_message(struct spi_controller *ctlr)
1701 {
1702         struct spi_transfer *xfer;
1703         struct spi_message *mesg;
1704         unsigned long flags;
1705         int ret;
1706
1707         spin_lock_irqsave(&ctlr->queue_lock, flags);
1708         mesg = ctlr->cur_msg;
1709         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1710
1711         if (!ctlr->ptp_sts_supported && !ctlr->transfer_one) {
1712                 list_for_each_entry(xfer, &mesg->transfers, transfer_list) {
1713                         ptp_read_system_postts(xfer->ptp_sts);
1714                         xfer->ptp_sts_word_post = xfer->len;
1715                 }
1716         }
1717
1718         if (unlikely(ctlr->ptp_sts_supported))
1719                 list_for_each_entry(xfer, &mesg->transfers, transfer_list)
1720                         WARN_ON_ONCE(xfer->ptp_sts && !xfer->timestamped);
1721
1722         spi_unmap_msg(ctlr, mesg);
1723
1724         /* In the prepare_messages callback the spi bus has the opportunity to
1725          * split a transfer to smaller chunks.
1726          * Release splited transfers here since spi_map_msg is done on the
1727          * splited transfers.
1728          */
1729         spi_res_release(ctlr, mesg);
1730
1731         if (ctlr->cur_msg_prepared && ctlr->unprepare_message) {
1732                 ret = ctlr->unprepare_message(ctlr, mesg);
1733                 if (ret) {
1734                         dev_err(&ctlr->dev, "failed to unprepare message: %d\n",
1735                                 ret);
1736                 }
1737         }
1738
1739         spin_lock_irqsave(&ctlr->queue_lock, flags);
1740         ctlr->cur_msg = NULL;
1741         ctlr->cur_msg_prepared = false;
1742         ctlr->fallback = false;
1743         kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1744         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1745
1746         trace_spi_message_done(mesg);
1747
1748         mesg->state = NULL;
1749         if (mesg->complete)
1750                 mesg->complete(mesg->context);
1751 }
1752 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1753
1754 static int spi_start_queue(struct spi_controller *ctlr)
1755 {
1756         unsigned long flags;
1757
1758         spin_lock_irqsave(&ctlr->queue_lock, flags);
1759
1760         if (ctlr->running || ctlr->busy) {
1761                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1762                 return -EBUSY;
1763         }
1764
1765         ctlr->running = true;
1766         ctlr->cur_msg = NULL;
1767         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1768
1769         kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1770
1771         return 0;
1772 }
1773
1774 static int spi_stop_queue(struct spi_controller *ctlr)
1775 {
1776         unsigned long flags;
1777         unsigned limit = 500;
1778         int ret = 0;
1779
1780         spin_lock_irqsave(&ctlr->queue_lock, flags);
1781
1782         /*
1783          * This is a bit lame, but is optimized for the common execution path.
1784          * A wait_queue on the ctlr->busy could be used, but then the common
1785          * execution path (pump_messages) would be required to call wake_up or
1786          * friends on every SPI message. Do this instead.
1787          */
1788         while ((!list_empty(&ctlr->queue) || ctlr->busy) && limit--) {
1789                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1790                 usleep_range(10000, 11000);
1791                 spin_lock_irqsave(&ctlr->queue_lock, flags);
1792         }
1793
1794         if (!list_empty(&ctlr->queue) || ctlr->busy)
1795                 ret = -EBUSY;
1796         else
1797                 ctlr->running = false;
1798
1799         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1800
1801         if (ret) {
1802                 dev_warn(&ctlr->dev, "could not stop message queue\n");
1803                 return ret;
1804         }
1805         return ret;
1806 }
1807
1808 static int spi_destroy_queue(struct spi_controller *ctlr)
1809 {
1810         int ret;
1811
1812         ret = spi_stop_queue(ctlr);
1813
1814         /*
1815          * kthread_flush_worker will block until all work is done.
1816          * If the reason that stop_queue timed out is that the work will never
1817          * finish, then it does no good to call flush/stop thread, so
1818          * return anyway.
1819          */
1820         if (ret) {
1821                 dev_err(&ctlr->dev, "problem destroying queue\n");
1822                 return ret;
1823         }
1824
1825         kthread_destroy_worker(ctlr->kworker);
1826
1827         return 0;
1828 }
1829
1830 static int __spi_queued_transfer(struct spi_device *spi,
1831                                  struct spi_message *msg,
1832                                  bool need_pump)
1833 {
1834         struct spi_controller *ctlr = spi->controller;
1835         unsigned long flags;
1836
1837         spin_lock_irqsave(&ctlr->queue_lock, flags);
1838
1839         if (!ctlr->running) {
1840                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1841                 return -ESHUTDOWN;
1842         }
1843         msg->actual_length = 0;
1844         msg->status = -EINPROGRESS;
1845
1846         list_add_tail(&msg->queue, &ctlr->queue);
1847         if (!ctlr->busy && need_pump)
1848                 kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1849
1850         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1851         return 0;
1852 }
1853
1854 /**
1855  * spi_queued_transfer - transfer function for queued transfers
1856  * @spi: spi device which is requesting transfer
1857  * @msg: spi message which is to handled is queued to driver queue
1858  *
1859  * Return: zero on success, else a negative error code.
1860  */
1861 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1862 {
1863         return __spi_queued_transfer(spi, msg, true);
1864 }
1865
1866 static int spi_controller_initialize_queue(struct spi_controller *ctlr)
1867 {
1868         int ret;
1869
1870         ctlr->transfer = spi_queued_transfer;
1871         if (!ctlr->transfer_one_message)
1872                 ctlr->transfer_one_message = spi_transfer_one_message;
1873
1874         /* Initialize and start queue */
1875         ret = spi_init_queue(ctlr);
1876         if (ret) {
1877                 dev_err(&ctlr->dev, "problem initializing queue\n");
1878                 goto err_init_queue;
1879         }
1880         ctlr->queued = true;
1881         ret = spi_start_queue(ctlr);
1882         if (ret) {
1883                 dev_err(&ctlr->dev, "problem starting queue\n");
1884                 goto err_start_queue;
1885         }
1886
1887         return 0;
1888
1889 err_start_queue:
1890         spi_destroy_queue(ctlr);
1891 err_init_queue:
1892         return ret;
1893 }
1894
1895 /**
1896  * spi_flush_queue - Send all pending messages in the queue from the callers'
1897  *                   context
1898  * @ctlr: controller to process queue for
1899  *
1900  * This should be used when one wants to ensure all pending messages have been
1901  * sent before doing something. Is used by the spi-mem code to make sure SPI
1902  * memory operations do not preempt regular SPI transfers that have been queued
1903  * before the spi-mem operation.
1904  */
1905 void spi_flush_queue(struct spi_controller *ctlr)
1906 {
1907         if (ctlr->transfer == spi_queued_transfer)
1908                 __spi_pump_messages(ctlr, false);
1909 }
1910
1911 /*-------------------------------------------------------------------------*/
1912
1913 #if defined(CONFIG_OF)
1914 static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
1915                            struct device_node *nc)
1916 {
1917         u32 value;
1918         int rc;
1919
1920         /* Mode (clock phase/polarity/etc.) */
1921         if (of_property_read_bool(nc, "spi-cpha"))
1922                 spi->mode |= SPI_CPHA;
1923         if (of_property_read_bool(nc, "spi-cpol"))
1924                 spi->mode |= SPI_CPOL;
1925         if (of_property_read_bool(nc, "spi-3wire"))
1926                 spi->mode |= SPI_3WIRE;
1927         if (of_property_read_bool(nc, "spi-lsb-first"))
1928                 spi->mode |= SPI_LSB_FIRST;
1929         if (of_property_read_bool(nc, "spi-cs-high"))
1930                 spi->mode |= SPI_CS_HIGH;
1931
1932         /* Device DUAL/QUAD mode */
1933         if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1934                 switch (value) {
1935                 case 1:
1936                         break;
1937                 case 2:
1938                         spi->mode |= SPI_TX_DUAL;
1939                         break;
1940                 case 4:
1941                         spi->mode |= SPI_TX_QUAD;
1942                         break;
1943                 case 8:
1944                         spi->mode |= SPI_TX_OCTAL;
1945                         break;
1946                 default:
1947                         dev_warn(&ctlr->dev,
1948                                 "spi-tx-bus-width %d not supported\n",
1949                                 value);
1950                         break;
1951                 }
1952         }
1953
1954         if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1955                 switch (value) {
1956                 case 1:
1957                         break;
1958                 case 2:
1959                         spi->mode |= SPI_RX_DUAL;
1960                         break;
1961                 case 4:
1962                         spi->mode |= SPI_RX_QUAD;
1963                         break;
1964                 case 8:
1965                         spi->mode |= SPI_RX_OCTAL;
1966                         break;
1967                 default:
1968                         dev_warn(&ctlr->dev,
1969                                 "spi-rx-bus-width %d not supported\n",
1970                                 value);
1971                         break;
1972                 }
1973         }
1974
1975         if (spi_controller_is_slave(ctlr)) {
1976                 if (!of_node_name_eq(nc, "slave")) {
1977                         dev_err(&ctlr->dev, "%pOF is not called 'slave'\n",
1978                                 nc);
1979                         return -EINVAL;
1980                 }
1981                 return 0;
1982         }
1983
1984         /* Device address */
1985         rc = of_property_read_u32(nc, "reg", &value);
1986         if (rc) {
1987                 dev_err(&ctlr->dev, "%pOF has no valid 'reg' property (%d)\n",
1988                         nc, rc);
1989                 return rc;
1990         }
1991         spi->chip_select = value;
1992
1993         /* Device speed */
1994         if (!of_property_read_u32(nc, "spi-max-frequency", &value))
1995                 spi->max_speed_hz = value;
1996
1997         return 0;
1998 }
1999
2000 static struct spi_device *
2001 of_register_spi_device(struct spi_controller *ctlr, struct device_node *nc)
2002 {
2003         struct spi_device *spi;
2004         int rc;
2005
2006         /* Alloc an spi_device */
2007         spi = spi_alloc_device(ctlr);
2008         if (!spi) {
2009                 dev_err(&ctlr->dev, "spi_device alloc error for %pOF\n", nc);
2010                 rc = -ENOMEM;
2011                 goto err_out;
2012         }
2013
2014         /* Select device driver */
2015         rc = of_modalias_node(nc, spi->modalias,
2016                                 sizeof(spi->modalias));
2017         if (rc < 0) {
2018                 dev_err(&ctlr->dev, "cannot find modalias for %pOF\n", nc);
2019                 goto err_out;
2020         }
2021
2022         rc = of_spi_parse_dt(ctlr, spi, nc);
2023         if (rc)
2024                 goto err_out;
2025
2026         /* Store a pointer to the node in the device structure */
2027         of_node_get(nc);
2028         spi->dev.of_node = nc;
2029
2030         /* Register the new device */
2031         rc = spi_add_device(spi);
2032         if (rc) {
2033                 dev_err(&ctlr->dev, "spi_device register error %pOF\n", nc);
2034                 goto err_of_node_put;
2035         }
2036
2037         return spi;
2038
2039 err_of_node_put:
2040         of_node_put(nc);
2041 err_out:
2042         spi_dev_put(spi);
2043         return ERR_PTR(rc);
2044 }
2045
2046 /**
2047  * of_register_spi_devices() - Register child devices onto the SPI bus
2048  * @ctlr:       Pointer to spi_controller device
2049  *
2050  * Registers an spi_device for each child node of controller node which
2051  * represents a valid SPI slave.
2052  */
2053 static void of_register_spi_devices(struct spi_controller *ctlr)
2054 {
2055         struct spi_device *spi;
2056         struct device_node *nc;
2057
2058         if (!ctlr->dev.of_node)
2059                 return;
2060
2061         for_each_available_child_of_node(ctlr->dev.of_node, nc) {
2062                 if (of_node_test_and_set_flag(nc, OF_POPULATED))
2063                         continue;
2064                 spi = of_register_spi_device(ctlr, nc);
2065                 if (IS_ERR(spi)) {
2066                         dev_warn(&ctlr->dev,
2067                                  "Failed to create SPI device for %pOF\n", nc);
2068                         of_node_clear_flag(nc, OF_POPULATED);
2069                 }
2070         }
2071 }
2072 #else
2073 static void of_register_spi_devices(struct spi_controller *ctlr) { }
2074 #endif
2075
2076 #ifdef CONFIG_ACPI
2077 struct acpi_spi_lookup {
2078         struct spi_controller   *ctlr;
2079         u32                     max_speed_hz;
2080         u32                     mode;
2081         int                     irq;
2082         u8                      bits_per_word;
2083         u8                      chip_select;
2084 };
2085
2086 static void acpi_spi_parse_apple_properties(struct acpi_device *dev,
2087                                             struct acpi_spi_lookup *lookup)
2088 {
2089         const union acpi_object *obj;
2090
2091         if (!x86_apple_machine)
2092                 return;
2093
2094         if (!acpi_dev_get_property(dev, "spiSclkPeriod", ACPI_TYPE_BUFFER, &obj)
2095             && obj->buffer.length >= 4)
2096                 lookup->max_speed_hz  = NSEC_PER_SEC / *(u32 *)obj->buffer.pointer;
2097
2098         if (!acpi_dev_get_property(dev, "spiWordSize", ACPI_TYPE_BUFFER, &obj)
2099             && obj->buffer.length == 8)
2100                 lookup->bits_per_word = *(u64 *)obj->buffer.pointer;
2101
2102         if (!acpi_dev_get_property(dev, "spiBitOrder", ACPI_TYPE_BUFFER, &obj)
2103             && obj->buffer.length == 8 && !*(u64 *)obj->buffer.pointer)
2104                 lookup->mode |= SPI_LSB_FIRST;
2105
2106         if (!acpi_dev_get_property(dev, "spiSPO", ACPI_TYPE_BUFFER, &obj)
2107             && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
2108                 lookup->mode |= SPI_CPOL;
2109
2110         if (!acpi_dev_get_property(dev, "spiSPH", ACPI_TYPE_BUFFER, &obj)
2111             && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
2112                 lookup->mode |= SPI_CPHA;
2113 }
2114
2115 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
2116 {
2117         struct acpi_spi_lookup *lookup = data;
2118         struct spi_controller *ctlr = lookup->ctlr;
2119
2120         if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
2121                 struct acpi_resource_spi_serialbus *sb;
2122                 acpi_handle parent_handle;
2123                 acpi_status status;
2124
2125                 sb = &ares->data.spi_serial_bus;
2126                 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
2127
2128                         status = acpi_get_handle(NULL,
2129                                                  sb->resource_source.string_ptr,
2130                                                  &parent_handle);
2131
2132                         if (ACPI_FAILURE(status) ||
2133                             ACPI_HANDLE(ctlr->dev.parent) != parent_handle)
2134                                 return -ENODEV;
2135
2136                         /*
2137                          * ACPI DeviceSelection numbering is handled by the
2138                          * host controller driver in Windows and can vary
2139                          * from driver to driver. In Linux we always expect
2140                          * 0 .. max - 1 so we need to ask the driver to
2141                          * translate between the two schemes.
2142                          */
2143                         if (ctlr->fw_translate_cs) {
2144                                 int cs = ctlr->fw_translate_cs(ctlr,
2145                                                 sb->device_selection);
2146                                 if (cs < 0)
2147                                         return cs;
2148                                 lookup->chip_select = cs;
2149                         } else {
2150                                 lookup->chip_select = sb->device_selection;
2151                         }
2152
2153                         lookup->max_speed_hz = sb->connection_speed;
2154                         lookup->bits_per_word = sb->data_bit_length;
2155
2156                         if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
2157                                 lookup->mode |= SPI_CPHA;
2158                         if (sb->clock_polarity == ACPI_SPI_START_HIGH)
2159                                 lookup->mode |= SPI_CPOL;
2160                         if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
2161                                 lookup->mode |= SPI_CS_HIGH;
2162                 }
2163         } else if (lookup->irq < 0) {
2164                 struct resource r;
2165
2166                 if (acpi_dev_resource_interrupt(ares, 0, &r))
2167                         lookup->irq = r.start;
2168         }
2169
2170         /* Always tell the ACPI core to skip this resource */
2171         return 1;
2172 }
2173
2174 static acpi_status acpi_register_spi_device(struct spi_controller *ctlr,
2175                                             struct acpi_device *adev)
2176 {
2177         acpi_handle parent_handle = NULL;
2178         struct list_head resource_list;
2179         struct acpi_spi_lookup lookup = {};
2180         struct spi_device *spi;
2181         int ret;
2182
2183         if (acpi_bus_get_status(adev) || !adev->status.present ||
2184             acpi_device_enumerated(adev))
2185                 return AE_OK;
2186
2187         lookup.ctlr             = ctlr;
2188         lookup.irq              = -1;
2189
2190         INIT_LIST_HEAD(&resource_list);
2191         ret = acpi_dev_get_resources(adev, &resource_list,
2192                                      acpi_spi_add_resource, &lookup);
2193         acpi_dev_free_resource_list(&resource_list);
2194
2195         if (ret < 0)
2196                 /* found SPI in _CRS but it points to another controller */
2197                 return AE_OK;
2198
2199         if (!lookup.max_speed_hz &&
2200             !ACPI_FAILURE(acpi_get_parent(adev->handle, &parent_handle)) &&
2201             ACPI_HANDLE(ctlr->dev.parent) == parent_handle) {
2202                 /* Apple does not use _CRS but nested devices for SPI slaves */
2203                 acpi_spi_parse_apple_properties(adev, &lookup);
2204         }
2205
2206         if (!lookup.max_speed_hz)
2207                 return AE_OK;
2208
2209         spi = spi_alloc_device(ctlr);
2210         if (!spi) {
2211                 dev_err(&ctlr->dev, "failed to allocate SPI device for %s\n",
2212                         dev_name(&adev->dev));
2213                 return AE_NO_MEMORY;
2214         }
2215
2216
2217         ACPI_COMPANION_SET(&spi->dev, adev);
2218         spi->max_speed_hz       = lookup.max_speed_hz;
2219         spi->mode               |= lookup.mode;
2220         spi->irq                = lookup.irq;
2221         spi->bits_per_word      = lookup.bits_per_word;
2222         spi->chip_select        = lookup.chip_select;
2223
2224         acpi_set_modalias(adev, acpi_device_hid(adev), spi->modalias,
2225                           sizeof(spi->modalias));
2226
2227         if (spi->irq < 0)
2228                 spi->irq = acpi_dev_gpio_irq_get(adev, 0);
2229
2230         acpi_device_set_enumerated(adev);
2231
2232         adev->power.flags.ignore_parent = true;
2233         if (spi_add_device(spi)) {
2234                 adev->power.flags.ignore_parent = false;
2235                 dev_err(&ctlr->dev, "failed to add SPI device %s from ACPI\n",
2236                         dev_name(&adev->dev));
2237                 spi_dev_put(spi);
2238         }
2239
2240         return AE_OK;
2241 }
2242
2243 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
2244                                        void *data, void **return_value)
2245 {
2246         struct spi_controller *ctlr = data;
2247         struct acpi_device *adev;
2248
2249         if (acpi_bus_get_device(handle, &adev))
2250                 return AE_OK;
2251
2252         return acpi_register_spi_device(ctlr, adev);
2253 }
2254
2255 #define SPI_ACPI_ENUMERATE_MAX_DEPTH            32
2256
2257 static void acpi_register_spi_devices(struct spi_controller *ctlr)
2258 {
2259         acpi_status status;
2260         acpi_handle handle;
2261
2262         handle = ACPI_HANDLE(ctlr->dev.parent);
2263         if (!handle)
2264                 return;
2265
2266         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
2267                                      SPI_ACPI_ENUMERATE_MAX_DEPTH,
2268                                      acpi_spi_add_device, NULL, ctlr, NULL);
2269         if (ACPI_FAILURE(status))
2270                 dev_warn(&ctlr->dev, "failed to enumerate SPI slaves\n");
2271 }
2272 #else
2273 static inline void acpi_register_spi_devices(struct spi_controller *ctlr) {}
2274 #endif /* CONFIG_ACPI */
2275
2276 static void spi_controller_release(struct device *dev)
2277 {
2278         struct spi_controller *ctlr;
2279
2280         ctlr = container_of(dev, struct spi_controller, dev);
2281         kfree(ctlr);
2282 }
2283
2284 static struct class spi_master_class = {
2285         .name           = "spi_master",
2286         .owner          = THIS_MODULE,
2287         .dev_release    = spi_controller_release,
2288         .dev_groups     = spi_master_groups,
2289 };
2290
2291 #ifdef CONFIG_SPI_SLAVE
2292 /**
2293  * spi_slave_abort - abort the ongoing transfer request on an SPI slave
2294  *                   controller
2295  * @spi: device used for the current transfer
2296  */
2297 int spi_slave_abort(struct spi_device *spi)
2298 {
2299         struct spi_controller *ctlr = spi->controller;
2300
2301         if (spi_controller_is_slave(ctlr) && ctlr->slave_abort)
2302                 return ctlr->slave_abort(ctlr);
2303
2304         return -ENOTSUPP;
2305 }
2306 EXPORT_SYMBOL_GPL(spi_slave_abort);
2307
2308 static int match_true(struct device *dev, void *data)
2309 {
2310         return 1;
2311 }
2312
2313 static ssize_t slave_show(struct device *dev, struct device_attribute *attr,
2314                           char *buf)
2315 {
2316         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2317                                                    dev);
2318         struct device *child;
2319
2320         child = device_find_child(&ctlr->dev, NULL, match_true);
2321         return sprintf(buf, "%s\n",
2322                        child ? to_spi_device(child)->modalias : NULL);
2323 }
2324
2325 static ssize_t slave_store(struct device *dev, struct device_attribute *attr,
2326                            const char *buf, size_t count)
2327 {
2328         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2329                                                    dev);
2330         struct spi_device *spi;
2331         struct device *child;
2332         char name[32];
2333         int rc;
2334
2335         rc = sscanf(buf, "%31s", name);
2336         if (rc != 1 || !name[0])
2337                 return -EINVAL;
2338
2339         child = device_find_child(&ctlr->dev, NULL, match_true);
2340         if (child) {
2341                 /* Remove registered slave */
2342                 device_unregister(child);
2343                 put_device(child);
2344         }
2345
2346         if (strcmp(name, "(null)")) {
2347                 /* Register new slave */
2348                 spi = spi_alloc_device(ctlr);
2349                 if (!spi)
2350                         return -ENOMEM;
2351
2352                 strlcpy(spi->modalias, name, sizeof(spi->modalias));
2353
2354                 rc = spi_add_device(spi);
2355                 if (rc) {
2356                         spi_dev_put(spi);
2357                         return rc;
2358                 }
2359         }
2360
2361         return count;
2362 }
2363
2364 static DEVICE_ATTR_RW(slave);
2365
2366 static struct attribute *spi_slave_attrs[] = {
2367         &dev_attr_slave.attr,
2368         NULL,
2369 };
2370
2371 static const struct attribute_group spi_slave_group = {
2372         .attrs = spi_slave_attrs,
2373 };
2374
2375 static const struct attribute_group *spi_slave_groups[] = {
2376         &spi_controller_statistics_group,
2377         &spi_slave_group,
2378         NULL,
2379 };
2380
2381 static struct class spi_slave_class = {
2382         .name           = "spi_slave",
2383         .owner          = THIS_MODULE,
2384         .dev_release    = spi_controller_release,
2385         .dev_groups     = spi_slave_groups,
2386 };
2387 #else
2388 extern struct class spi_slave_class;    /* dummy */
2389 #endif
2390
2391 /**
2392  * __spi_alloc_controller - allocate an SPI master or slave controller
2393  * @dev: the controller, possibly using the platform_bus
2394  * @size: how much zeroed driver-private data to allocate; the pointer to this
2395  *      memory is in the driver_data field of the returned device, accessible
2396  *      with spi_controller_get_devdata(); the memory is cacheline aligned;
2397  *      drivers granting DMA access to portions of their private data need to
2398  *      round up @size using ALIGN(size, dma_get_cache_alignment()).
2399  * @slave: flag indicating whether to allocate an SPI master (false) or SPI
2400  *      slave (true) controller
2401  * Context: can sleep
2402  *
2403  * This call is used only by SPI controller drivers, which are the
2404  * only ones directly touching chip registers.  It's how they allocate
2405  * an spi_controller structure, prior to calling spi_register_controller().
2406  *
2407  * This must be called from context that can sleep.
2408  *
2409  * The caller is responsible for assigning the bus number and initializing the
2410  * controller's methods before calling spi_register_controller(); and (after
2411  * errors adding the device) calling spi_controller_put() to prevent a memory
2412  * leak.
2413  *
2414  * Return: the SPI controller structure on success, else NULL.
2415  */
2416 struct spi_controller *__spi_alloc_controller(struct device *dev,
2417                                               unsigned int size, bool slave)
2418 {
2419         struct spi_controller   *ctlr;
2420         size_t ctlr_size = ALIGN(sizeof(*ctlr), dma_get_cache_alignment());
2421
2422         if (!dev)
2423                 return NULL;
2424
2425         ctlr = kzalloc(size + ctlr_size, GFP_KERNEL);
2426         if (!ctlr)
2427                 return NULL;
2428
2429         device_initialize(&ctlr->dev);
2430         ctlr->bus_num = -1;
2431         ctlr->num_chipselect = 1;
2432         ctlr->slave = slave;
2433         if (IS_ENABLED(CONFIG_SPI_SLAVE) && slave)
2434                 ctlr->dev.class = &spi_slave_class;
2435         else
2436                 ctlr->dev.class = &spi_master_class;
2437         ctlr->dev.parent = dev;
2438         pm_suspend_ignore_children(&ctlr->dev, true);
2439         spi_controller_set_devdata(ctlr, (void *)ctlr + ctlr_size);
2440
2441         return ctlr;
2442 }
2443 EXPORT_SYMBOL_GPL(__spi_alloc_controller);
2444
2445 #ifdef CONFIG_OF
2446 static int of_spi_get_gpio_numbers(struct spi_controller *ctlr)
2447 {
2448         int nb, i, *cs;
2449         struct device_node *np = ctlr->dev.of_node;
2450
2451         if (!np)
2452                 return 0;
2453
2454         nb = of_gpio_named_count(np, "cs-gpios");
2455         ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2456
2457         /* Return error only for an incorrectly formed cs-gpios property */
2458         if (nb == 0 || nb == -ENOENT)
2459                 return 0;
2460         else if (nb < 0)
2461                 return nb;
2462
2463         cs = devm_kcalloc(&ctlr->dev, ctlr->num_chipselect, sizeof(int),
2464                           GFP_KERNEL);
2465         ctlr->cs_gpios = cs;
2466
2467         if (!ctlr->cs_gpios)
2468                 return -ENOMEM;
2469
2470         for (i = 0; i < ctlr->num_chipselect; i++)
2471                 cs[i] = -ENOENT;
2472
2473         for (i = 0; i < nb; i++)
2474                 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
2475
2476         return 0;
2477 }
2478 #else
2479 static int of_spi_get_gpio_numbers(struct spi_controller *ctlr)
2480 {
2481         return 0;
2482 }
2483 #endif
2484
2485 /**
2486  * spi_get_gpio_descs() - grab chip select GPIOs for the master
2487  * @ctlr: The SPI master to grab GPIO descriptors for
2488  */
2489 static int spi_get_gpio_descs(struct spi_controller *ctlr)
2490 {
2491         int nb, i;
2492         struct gpio_desc **cs;
2493         struct device *dev = &ctlr->dev;
2494         unsigned long native_cs_mask = 0;
2495         unsigned int num_cs_gpios = 0;
2496
2497         nb = gpiod_count(dev, "cs");
2498         ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2499
2500         /* No GPIOs at all is fine, else return the error */
2501         if (nb == 0 || nb == -ENOENT)
2502                 return 0;
2503         else if (nb < 0)
2504                 return nb;
2505
2506         cs = devm_kcalloc(dev, ctlr->num_chipselect, sizeof(*cs),
2507                           GFP_KERNEL);
2508         if (!cs)
2509                 return -ENOMEM;
2510         ctlr->cs_gpiods = cs;
2511
2512         for (i = 0; i < nb; i++) {
2513                 /*
2514                  * Most chipselects are active low, the inverted
2515                  * semantics are handled by special quirks in gpiolib,
2516                  * so initializing them GPIOD_OUT_LOW here means
2517                  * "unasserted", in most cases this will drive the physical
2518                  * line high.
2519                  */
2520                 cs[i] = devm_gpiod_get_index_optional(dev, "cs", i,
2521                                                       GPIOD_OUT_LOW);
2522                 if (IS_ERR(cs[i]))
2523                         return PTR_ERR(cs[i]);
2524
2525                 if (cs[i]) {
2526                         /*
2527                          * If we find a CS GPIO, name it after the device and
2528                          * chip select line.
2529                          */
2530                         char *gpioname;
2531
2532                         gpioname = devm_kasprintf(dev, GFP_KERNEL, "%s CS%d",
2533                                                   dev_name(dev), i);
2534                         if (!gpioname)
2535                                 return -ENOMEM;
2536                         gpiod_set_consumer_name(cs[i], gpioname);
2537                         num_cs_gpios++;
2538                         continue;
2539                 }
2540
2541                 if (ctlr->max_native_cs && i >= ctlr->max_native_cs) {
2542                         dev_err(dev, "Invalid native chip select %d\n", i);
2543                         return -EINVAL;
2544                 }
2545                 native_cs_mask |= BIT(i);
2546         }
2547
2548         ctlr->unused_native_cs = ffz(native_cs_mask);
2549         if (num_cs_gpios && ctlr->max_native_cs &&
2550             ctlr->unused_native_cs >= ctlr->max_native_cs) {
2551                 dev_err(dev, "No unused native chip select available\n");
2552                 return -EINVAL;
2553         }
2554
2555         return 0;
2556 }
2557
2558 static int spi_controller_check_ops(struct spi_controller *ctlr)
2559 {
2560         /*
2561          * The controller may implement only the high-level SPI-memory like
2562          * operations if it does not support regular SPI transfers, and this is
2563          * valid use case.
2564          * If ->mem_ops is NULL, we request that at least one of the
2565          * ->transfer_xxx() method be implemented.
2566          */
2567         if (ctlr->mem_ops) {
2568                 if (!ctlr->mem_ops->exec_op)
2569                         return -EINVAL;
2570         } else if (!ctlr->transfer && !ctlr->transfer_one &&
2571                    !ctlr->transfer_one_message) {
2572                 return -EINVAL;
2573         }
2574
2575         return 0;
2576 }
2577
2578 /**
2579  * spi_register_controller - register SPI master or slave controller
2580  * @ctlr: initialized master, originally from spi_alloc_master() or
2581  *      spi_alloc_slave()
2582  * Context: can sleep
2583  *
2584  * SPI controllers connect to their drivers using some non-SPI bus,
2585  * such as the platform bus.  The final stage of probe() in that code
2586  * includes calling spi_register_controller() to hook up to this SPI bus glue.
2587  *
2588  * SPI controllers use board specific (often SOC specific) bus numbers,
2589  * and board-specific addressing for SPI devices combines those numbers
2590  * with chip select numbers.  Since SPI does not directly support dynamic
2591  * device identification, boards need configuration tables telling which
2592  * chip is at which address.
2593  *
2594  * This must be called from context that can sleep.  It returns zero on
2595  * success, else a negative error code (dropping the controller's refcount).
2596  * After a successful return, the caller is responsible for calling
2597  * spi_unregister_controller().
2598  *
2599  * Return: zero on success, else a negative error code.
2600  */
2601 int spi_register_controller(struct spi_controller *ctlr)
2602 {
2603         struct device           *dev = ctlr->dev.parent;
2604         struct boardinfo        *bi;
2605         int                     status;
2606         int                     id, first_dynamic;
2607
2608         if (!dev)
2609                 return -ENODEV;
2610
2611         /*
2612          * Make sure all necessary hooks are implemented before registering
2613          * the SPI controller.
2614          */
2615         status = spi_controller_check_ops(ctlr);
2616         if (status)
2617                 return status;
2618
2619         if (ctlr->bus_num >= 0) {
2620                 /* devices with a fixed bus num must check-in with the num */
2621                 mutex_lock(&board_lock);
2622                 id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
2623                         ctlr->bus_num + 1, GFP_KERNEL);
2624                 mutex_unlock(&board_lock);
2625                 if (WARN(id < 0, "couldn't get idr"))
2626                         return id == -ENOSPC ? -EBUSY : id;
2627                 ctlr->bus_num = id;
2628         } else if (ctlr->dev.of_node) {
2629                 /* allocate dynamic bus number using Linux idr */
2630                 id = of_alias_get_id(ctlr->dev.of_node, "spi");
2631                 if (id >= 0) {
2632                         ctlr->bus_num = id;
2633                         mutex_lock(&board_lock);
2634                         id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
2635                                        ctlr->bus_num + 1, GFP_KERNEL);
2636                         mutex_unlock(&board_lock);
2637                         if (WARN(id < 0, "couldn't get idr"))
2638                                 return id == -ENOSPC ? -EBUSY : id;
2639                 }
2640         }
2641         if (ctlr->bus_num < 0) {
2642                 first_dynamic = of_alias_get_highest_id("spi");
2643                 if (first_dynamic < 0)
2644                         first_dynamic = 0;
2645                 else
2646                         first_dynamic++;
2647
2648                 mutex_lock(&board_lock);
2649                 id = idr_alloc(&spi_master_idr, ctlr, first_dynamic,
2650                                0, GFP_KERNEL);
2651                 mutex_unlock(&board_lock);
2652                 if (WARN(id < 0, "couldn't get idr"))
2653                         return id;
2654                 ctlr->bus_num = id;
2655         }
2656         INIT_LIST_HEAD(&ctlr->queue);
2657         spin_lock_init(&ctlr->queue_lock);
2658         spin_lock_init(&ctlr->bus_lock_spinlock);
2659         mutex_init(&ctlr->bus_lock_mutex);
2660         mutex_init(&ctlr->io_mutex);
2661         ctlr->bus_lock_flag = 0;
2662         init_completion(&ctlr->xfer_completion);
2663         if (!ctlr->max_dma_len)
2664                 ctlr->max_dma_len = INT_MAX;
2665
2666         /* register the device, then userspace will see it.
2667          * registration fails if the bus ID is in use.
2668          */
2669         dev_set_name(&ctlr->dev, "spi%u", ctlr->bus_num);
2670
2671         if (!spi_controller_is_slave(ctlr)) {
2672                 if (ctlr->use_gpio_descriptors) {
2673                         status = spi_get_gpio_descs(ctlr);
2674                         if (status)
2675                                 goto free_bus_id;
2676                         /*
2677                          * A controller using GPIO descriptors always
2678                          * supports SPI_CS_HIGH if need be.
2679                          */
2680                         ctlr->mode_bits |= SPI_CS_HIGH;
2681                 } else {
2682                         /* Legacy code path for GPIOs from DT */
2683                         status = of_spi_get_gpio_numbers(ctlr);
2684                         if (status)
2685                                 goto free_bus_id;
2686                 }
2687         }
2688
2689         /*
2690          * Even if it's just one always-selected device, there must
2691          * be at least one chipselect.
2692          */
2693         if (!ctlr->num_chipselect) {
2694                 status = -EINVAL;
2695                 goto free_bus_id;
2696         }
2697
2698         status = device_add(&ctlr->dev);
2699         if (status < 0)
2700                 goto free_bus_id;
2701         dev_dbg(dev, "registered %s %s\n",
2702                         spi_controller_is_slave(ctlr) ? "slave" : "master",
2703                         dev_name(&ctlr->dev));
2704
2705         /*
2706          * If we're using a queued driver, start the queue. Note that we don't
2707          * need the queueing logic if the driver is only supporting high-level
2708          * memory operations.
2709          */
2710         if (ctlr->transfer) {
2711                 dev_info(dev, "controller is unqueued, this is deprecated\n");
2712         } else if (ctlr->transfer_one || ctlr->transfer_one_message) {
2713                 status = spi_controller_initialize_queue(ctlr);
2714                 if (status) {
2715                         device_del(&ctlr->dev);
2716                         goto free_bus_id;
2717                 }
2718         }
2719         /* add statistics */
2720         spin_lock_init(&ctlr->statistics.lock);
2721
2722         mutex_lock(&board_lock);
2723         list_add_tail(&ctlr->list, &spi_controller_list);
2724         list_for_each_entry(bi, &board_list, list)
2725                 spi_match_controller_to_boardinfo(ctlr, &bi->board_info);
2726         mutex_unlock(&board_lock);
2727
2728         /* Register devices from the device tree and ACPI */
2729         of_register_spi_devices(ctlr);
2730         acpi_register_spi_devices(ctlr);
2731         return status;
2732
2733 free_bus_id:
2734         mutex_lock(&board_lock);
2735         idr_remove(&spi_master_idr, ctlr->bus_num);
2736         mutex_unlock(&board_lock);
2737         return status;
2738 }
2739 EXPORT_SYMBOL_GPL(spi_register_controller);
2740
2741 static void devm_spi_unregister(struct device *dev, void *res)
2742 {
2743         spi_unregister_controller(*(struct spi_controller **)res);
2744 }
2745
2746 /**
2747  * devm_spi_register_controller - register managed SPI master or slave
2748  *      controller
2749  * @dev:    device managing SPI controller
2750  * @ctlr: initialized controller, originally from spi_alloc_master() or
2751  *      spi_alloc_slave()
2752  * Context: can sleep
2753  *
2754  * Register a SPI device as with spi_register_controller() which will
2755  * automatically be unregistered and freed.
2756  *
2757  * Return: zero on success, else a negative error code.
2758  */
2759 int devm_spi_register_controller(struct device *dev,
2760                                  struct spi_controller *ctlr)
2761 {
2762         struct spi_controller **ptr;
2763         int ret;
2764
2765         ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
2766         if (!ptr)
2767                 return -ENOMEM;
2768
2769         ret = spi_register_controller(ctlr);
2770         if (!ret) {
2771                 *ptr = ctlr;
2772                 devres_add(dev, ptr);
2773         } else {
2774                 devres_free(ptr);
2775         }
2776
2777         return ret;
2778 }
2779 EXPORT_SYMBOL_GPL(devm_spi_register_controller);
2780
2781 static int __unregister(struct device *dev, void *null)
2782 {
2783         spi_unregister_device(to_spi_device(dev));
2784         return 0;
2785 }
2786
2787 /**
2788  * spi_unregister_controller - unregister SPI master or slave controller
2789  * @ctlr: the controller being unregistered
2790  * Context: can sleep
2791  *
2792  * This call is used only by SPI controller drivers, which are the
2793  * only ones directly touching chip registers.
2794  *
2795  * This must be called from context that can sleep.
2796  *
2797  * Note that this function also drops a reference to the controller.
2798  */
2799 void spi_unregister_controller(struct spi_controller *ctlr)
2800 {
2801         struct spi_controller *found;
2802         int id = ctlr->bus_num;
2803
2804         /* Prevent addition of new devices, unregister existing ones */
2805         if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
2806                 mutex_lock(&spi_add_lock);
2807
2808         device_for_each_child(&ctlr->dev, NULL, __unregister);
2809
2810         /* First make sure that this controller was ever added */
2811         mutex_lock(&board_lock);
2812         found = idr_find(&spi_master_idr, id);
2813         mutex_unlock(&board_lock);
2814         if (ctlr->queued) {
2815                 if (spi_destroy_queue(ctlr))
2816                         dev_err(&ctlr->dev, "queue remove failed\n");
2817         }
2818         mutex_lock(&board_lock);
2819         list_del(&ctlr->list);
2820         mutex_unlock(&board_lock);
2821
2822         device_unregister(&ctlr->dev);
2823         /* free bus id */
2824         mutex_lock(&board_lock);
2825         if (found == ctlr)
2826                 idr_remove(&spi_master_idr, id);
2827         mutex_unlock(&board_lock);
2828
2829         if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
2830                 mutex_unlock(&spi_add_lock);
2831 }
2832 EXPORT_SYMBOL_GPL(spi_unregister_controller);
2833
2834 int spi_controller_suspend(struct spi_controller *ctlr)
2835 {
2836         int ret;
2837
2838         /* Basically no-ops for non-queued controllers */
2839         if (!ctlr->queued)
2840                 return 0;
2841
2842         ret = spi_stop_queue(ctlr);
2843         if (ret)
2844                 dev_err(&ctlr->dev, "queue stop failed\n");
2845
2846         return ret;
2847 }
2848 EXPORT_SYMBOL_GPL(spi_controller_suspend);
2849
2850 int spi_controller_resume(struct spi_controller *ctlr)
2851 {
2852         int ret;
2853
2854         if (!ctlr->queued)
2855                 return 0;
2856
2857         ret = spi_start_queue(ctlr);
2858         if (ret)
2859                 dev_err(&ctlr->dev, "queue restart failed\n");
2860
2861         return ret;
2862 }
2863 EXPORT_SYMBOL_GPL(spi_controller_resume);
2864
2865 static int __spi_controller_match(struct device *dev, const void *data)
2866 {
2867         struct spi_controller *ctlr;
2868         const u16 *bus_num = data;
2869
2870         ctlr = container_of(dev, struct spi_controller, dev);
2871         return ctlr->bus_num == *bus_num;
2872 }
2873
2874 /**
2875  * spi_busnum_to_master - look up master associated with bus_num
2876  * @bus_num: the master's bus number
2877  * Context: can sleep
2878  *
2879  * This call may be used with devices that are registered after
2880  * arch init time.  It returns a refcounted pointer to the relevant
2881  * spi_controller (which the caller must release), or NULL if there is
2882  * no such master registered.
2883  *
2884  * Return: the SPI master structure on success, else NULL.
2885  */
2886 struct spi_controller *spi_busnum_to_master(u16 bus_num)
2887 {
2888         struct device           *dev;
2889         struct spi_controller   *ctlr = NULL;
2890
2891         dev = class_find_device(&spi_master_class, NULL, &bus_num,
2892                                 __spi_controller_match);
2893         if (dev)
2894                 ctlr = container_of(dev, struct spi_controller, dev);
2895         /* reference got in class_find_device */
2896         return ctlr;
2897 }
2898 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
2899
2900 /*-------------------------------------------------------------------------*/
2901
2902 /* Core methods for SPI resource management */
2903
2904 /**
2905  * spi_res_alloc - allocate a spi resource that is life-cycle managed
2906  *                 during the processing of a spi_message while using
2907  *                 spi_transfer_one
2908  * @spi:     the spi device for which we allocate memory
2909  * @release: the release code to execute for this resource
2910  * @size:    size to alloc and return
2911  * @gfp:     GFP allocation flags
2912  *
2913  * Return: the pointer to the allocated data
2914  *
2915  * This may get enhanced in the future to allocate from a memory pool
2916  * of the @spi_device or @spi_controller to avoid repeated allocations.
2917  */
2918 void *spi_res_alloc(struct spi_device *spi,
2919                     spi_res_release_t release,
2920                     size_t size, gfp_t gfp)
2921 {
2922         struct spi_res *sres;
2923
2924         sres = kzalloc(sizeof(*sres) + size, gfp);
2925         if (!sres)
2926                 return NULL;
2927
2928         INIT_LIST_HEAD(&sres->entry);
2929         sres->release = release;
2930
2931         return sres->data;
2932 }
2933 EXPORT_SYMBOL_GPL(spi_res_alloc);
2934
2935 /**
2936  * spi_res_free - free an spi resource
2937  * @res: pointer to the custom data of a resource
2938  *
2939  */
2940 void spi_res_free(void *res)
2941 {
2942         struct spi_res *sres = container_of(res, struct spi_res, data);
2943
2944         if (!res)
2945                 return;
2946
2947         WARN_ON(!list_empty(&sres->entry));
2948         kfree(sres);
2949 }
2950 EXPORT_SYMBOL_GPL(spi_res_free);
2951
2952 /**
2953  * spi_res_add - add a spi_res to the spi_message
2954  * @message: the spi message
2955  * @res:     the spi_resource
2956  */
2957 void spi_res_add(struct spi_message *message, void *res)
2958 {
2959         struct spi_res *sres = container_of(res, struct spi_res, data);
2960
2961         WARN_ON(!list_empty(&sres->entry));
2962         list_add_tail(&sres->entry, &message->resources);
2963 }
2964 EXPORT_SYMBOL_GPL(spi_res_add);
2965
2966 /**
2967  * spi_res_release - release all spi resources for this message
2968  * @ctlr:  the @spi_controller
2969  * @message: the @spi_message
2970  */
2971 void spi_res_release(struct spi_controller *ctlr, struct spi_message *message)
2972 {
2973         struct spi_res *res, *tmp;
2974
2975         list_for_each_entry_safe_reverse(res, tmp, &message->resources, entry) {
2976                 if (res->release)
2977                         res->release(ctlr, message, res->data);
2978
2979                 list_del(&res->entry);
2980
2981                 kfree(res);
2982         }
2983 }
2984 EXPORT_SYMBOL_GPL(spi_res_release);
2985
2986 /*-------------------------------------------------------------------------*/
2987
2988 /* Core methods for spi_message alterations */
2989
2990 static void __spi_replace_transfers_release(struct spi_controller *ctlr,
2991                                             struct spi_message *msg,
2992                                             void *res)
2993 {
2994         struct spi_replaced_transfers *rxfer = res;
2995         size_t i;
2996
2997         /* call extra callback if requested */
2998         if (rxfer->release)
2999                 rxfer->release(ctlr, msg, res);
3000
3001         /* insert replaced transfers back into the message */
3002         list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
3003
3004         /* remove the formerly inserted entries */
3005         for (i = 0; i < rxfer->inserted; i++)
3006                 list_del(&rxfer->inserted_transfers[i].transfer_list);
3007 }
3008
3009 /**
3010  * spi_replace_transfers - replace transfers with several transfers
3011  *                         and register change with spi_message.resources
3012  * @msg:           the spi_message we work upon
3013  * @xfer_first:    the first spi_transfer we want to replace
3014  * @remove:        number of transfers to remove
3015  * @insert:        the number of transfers we want to insert instead
3016  * @release:       extra release code necessary in some circumstances
3017  * @extradatasize: extra data to allocate (with alignment guarantees
3018  *                 of struct @spi_transfer)
3019  * @gfp:           gfp flags
3020  *
3021  * Returns: pointer to @spi_replaced_transfers,
3022  *          PTR_ERR(...) in case of errors.
3023  */
3024 struct spi_replaced_transfers *spi_replace_transfers(
3025         struct spi_message *msg,
3026         struct spi_transfer *xfer_first,
3027         size_t remove,
3028         size_t insert,
3029         spi_replaced_release_t release,
3030         size_t extradatasize,
3031         gfp_t gfp)
3032 {
3033         struct spi_replaced_transfers *rxfer;
3034         struct spi_transfer *xfer;
3035         size_t i;
3036
3037         /* allocate the structure using spi_res */
3038         rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
3039                               struct_size(rxfer, inserted_transfers, insert)
3040                               + extradatasize,
3041                               gfp);
3042         if (!rxfer)
3043                 return ERR_PTR(-ENOMEM);
3044
3045         /* the release code to invoke before running the generic release */
3046         rxfer->release = release;
3047
3048         /* assign extradata */
3049         if (extradatasize)
3050                 rxfer->extradata =
3051                         &rxfer->inserted_transfers[insert];
3052
3053         /* init the replaced_transfers list */
3054         INIT_LIST_HEAD(&rxfer->replaced_transfers);
3055
3056         /* assign the list_entry after which we should reinsert
3057          * the @replaced_transfers - it may be spi_message.messages!
3058          */
3059         rxfer->replaced_after = xfer_first->transfer_list.prev;
3060
3061         /* remove the requested number of transfers */
3062         for (i = 0; i < remove; i++) {
3063                 /* if the entry after replaced_after it is msg->transfers
3064                  * then we have been requested to remove more transfers
3065                  * than are in the list
3066                  */
3067                 if (rxfer->replaced_after->next == &msg->transfers) {
3068                         dev_err(&msg->spi->dev,
3069                                 "requested to remove more spi_transfers than are available\n");
3070                         /* insert replaced transfers back into the message */
3071                         list_splice(&rxfer->replaced_transfers,
3072                                     rxfer->replaced_after);
3073
3074                         /* free the spi_replace_transfer structure */
3075                         spi_res_free(rxfer);
3076
3077                         /* and return with an error */
3078                         return ERR_PTR(-EINVAL);
3079                 }
3080
3081                 /* remove the entry after replaced_after from list of
3082                  * transfers and add it to list of replaced_transfers
3083                  */
3084                 list_move_tail(rxfer->replaced_after->next,
3085                                &rxfer->replaced_transfers);
3086         }
3087
3088         /* create copy of the given xfer with identical settings
3089          * based on the first transfer to get removed
3090          */
3091         for (i = 0; i < insert; i++) {
3092                 /* we need to run in reverse order */
3093                 xfer = &rxfer->inserted_transfers[insert - 1 - i];
3094
3095                 /* copy all spi_transfer data */
3096                 memcpy(xfer, xfer_first, sizeof(*xfer));
3097
3098                 /* add to list */
3099                 list_add(&xfer->transfer_list, rxfer->replaced_after);
3100
3101                 /* clear cs_change and delay for all but the last */
3102                 if (i) {
3103                         xfer->cs_change = false;
3104                         xfer->delay_usecs = 0;
3105                         xfer->delay.value = 0;
3106                 }
3107         }
3108
3109         /* set up inserted */
3110         rxfer->inserted = insert;
3111
3112         /* and register it with spi_res/spi_message */
3113         spi_res_add(msg, rxfer);
3114
3115         return rxfer;
3116 }
3117 EXPORT_SYMBOL_GPL(spi_replace_transfers);
3118
3119 static int __spi_split_transfer_maxsize(struct spi_controller *ctlr,
3120                                         struct spi_message *msg,
3121                                         struct spi_transfer **xferp,
3122                                         size_t maxsize,
3123                                         gfp_t gfp)
3124 {
3125         struct spi_transfer *xfer = *xferp, *xfers;
3126         struct spi_replaced_transfers *srt;
3127         size_t offset;
3128         size_t count, i;
3129
3130         /* calculate how many we have to replace */
3131         count = DIV_ROUND_UP(xfer->len, maxsize);
3132
3133         /* create replacement */
3134         srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
3135         if (IS_ERR(srt))
3136                 return PTR_ERR(srt);
3137         xfers = srt->inserted_transfers;
3138
3139         /* now handle each of those newly inserted spi_transfers
3140          * note that the replacements spi_transfers all are preset
3141          * to the same values as *xferp, so tx_buf, rx_buf and len
3142          * are all identical (as well as most others)
3143          * so we just have to fix up len and the pointers.
3144          *
3145          * this also includes support for the depreciated
3146          * spi_message.is_dma_mapped interface
3147          */
3148
3149         /* the first transfer just needs the length modified, so we
3150          * run it outside the loop
3151          */
3152         xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
3153
3154         /* all the others need rx_buf/tx_buf also set */
3155         for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
3156                 /* update rx_buf, tx_buf and dma */
3157                 if (xfers[i].rx_buf)
3158                         xfers[i].rx_buf += offset;
3159                 if (xfers[i].rx_dma)
3160                         xfers[i].rx_dma += offset;
3161                 if (xfers[i].tx_buf)
3162                         xfers[i].tx_buf += offset;
3163                 if (xfers[i].tx_dma)
3164                         xfers[i].tx_dma += offset;
3165
3166                 /* update length */
3167                 xfers[i].len = min(maxsize, xfers[i].len - offset);
3168         }
3169
3170         /* we set up xferp to the last entry we have inserted,
3171          * so that we skip those already split transfers
3172          */
3173         *xferp = &xfers[count - 1];
3174
3175         /* increment statistics counters */
3176         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
3177                                        transfers_split_maxsize);
3178         SPI_STATISTICS_INCREMENT_FIELD(&msg->spi->statistics,
3179                                        transfers_split_maxsize);
3180
3181         return 0;
3182 }
3183
3184 /**
3185  * spi_split_tranfers_maxsize - split spi transfers into multiple transfers
3186  *                              when an individual transfer exceeds a
3187  *                              certain size
3188  * @ctlr:    the @spi_controller for this transfer
3189  * @msg:   the @spi_message to transform
3190  * @maxsize:  the maximum when to apply this
3191  * @gfp: GFP allocation flags
3192  *
3193  * Return: status of transformation
3194  */
3195 int spi_split_transfers_maxsize(struct spi_controller *ctlr,
3196                                 struct spi_message *msg,
3197                                 size_t maxsize,
3198                                 gfp_t gfp)
3199 {
3200         struct spi_transfer *xfer;
3201         int ret;
3202
3203         /* iterate over the transfer_list,
3204          * but note that xfer is advanced to the last transfer inserted
3205          * to avoid checking sizes again unnecessarily (also xfer does
3206          * potentiall belong to a different list by the time the
3207          * replacement has happened
3208          */
3209         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
3210                 if (xfer->len > maxsize) {
3211                         ret = __spi_split_transfer_maxsize(ctlr, msg, &xfer,
3212                                                            maxsize, gfp);
3213                         if (ret)
3214                                 return ret;
3215                 }
3216         }
3217
3218         return 0;
3219 }
3220 EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
3221
3222 /*-------------------------------------------------------------------------*/
3223
3224 /* Core methods for SPI controller protocol drivers.  Some of the
3225  * other core methods are currently defined as inline functions.
3226  */
3227
3228 static int __spi_validate_bits_per_word(struct spi_controller *ctlr,
3229                                         u8 bits_per_word)
3230 {
3231         if (ctlr->bits_per_word_mask) {
3232                 /* Only 32 bits fit in the mask */
3233                 if (bits_per_word > 32)
3234                         return -EINVAL;
3235                 if (!(ctlr->bits_per_word_mask & SPI_BPW_MASK(bits_per_word)))
3236                         return -EINVAL;
3237         }
3238
3239         return 0;
3240 }
3241
3242 /**
3243  * spi_setup - setup SPI mode and clock rate
3244  * @spi: the device whose settings are being modified
3245  * Context: can sleep, and no requests are queued to the device
3246  *
3247  * SPI protocol drivers may need to update the transfer mode if the
3248  * device doesn't work with its default.  They may likewise need
3249  * to update clock rates or word sizes from initial values.  This function
3250  * changes those settings, and must be called from a context that can sleep.
3251  * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
3252  * effect the next time the device is selected and data is transferred to
3253  * or from it.  When this function returns, the spi device is deselected.
3254  *
3255  * Note that this call will fail if the protocol driver specifies an option
3256  * that the underlying controller or its driver does not support.  For
3257  * example, not all hardware supports wire transfers using nine bit words,
3258  * LSB-first wire encoding, or active-high chipselects.
3259  *
3260  * Return: zero on success, else a negative error code.
3261  */
3262 int spi_setup(struct spi_device *spi)
3263 {
3264         unsigned        bad_bits, ugly_bits;
3265         int             status;
3266
3267         /* check mode to prevent that DUAL and QUAD set at the same time
3268          */
3269         if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
3270                 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
3271                 dev_err(&spi->dev,
3272                 "setup: can not select dual and quad at the same time\n");
3273                 return -EINVAL;
3274         }
3275         /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
3276          */
3277         if ((spi->mode & SPI_3WIRE) && (spi->mode &
3278                 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
3279                  SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL)))
3280                 return -EINVAL;
3281         /* help drivers fail *cleanly* when they need options
3282          * that aren't supported with their current controller
3283          * SPI_CS_WORD has a fallback software implementation,
3284          * so it is ignored here.
3285          */
3286         bad_bits = spi->mode & ~(spi->controller->mode_bits | SPI_CS_WORD);
3287         /* nothing prevents from working with active-high CS in case if it
3288          * is driven by GPIO.
3289          */
3290         if (gpio_is_valid(spi->cs_gpio))
3291                 bad_bits &= ~SPI_CS_HIGH;
3292         ugly_bits = bad_bits &
3293                     (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
3294                      SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL);
3295         if (ugly_bits) {
3296                 dev_warn(&spi->dev,
3297                          "setup: ignoring unsupported mode bits %x\n",
3298                          ugly_bits);
3299                 spi->mode &= ~ugly_bits;
3300                 bad_bits &= ~ugly_bits;
3301         }
3302         if (bad_bits) {
3303                 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
3304                         bad_bits);
3305                 return -EINVAL;
3306         }
3307
3308         if (!spi->bits_per_word)
3309                 spi->bits_per_word = 8;
3310
3311         status = __spi_validate_bits_per_word(spi->controller,
3312                                               spi->bits_per_word);
3313         if (status)
3314                 return status;
3315
3316         if (!spi->max_speed_hz)
3317                 spi->max_speed_hz = spi->controller->max_speed_hz;
3318
3319         if (spi->controller->setup)
3320                 status = spi->controller->setup(spi);
3321
3322         if (spi->controller->auto_runtime_pm && spi->controller->set_cs) {
3323                 status = pm_runtime_get_sync(spi->controller->dev.parent);
3324                 if (status < 0) {
3325                         pm_runtime_put_noidle(spi->controller->dev.parent);
3326                         dev_err(&spi->controller->dev, "Failed to power device: %d\n",
3327                                 status);
3328                         return status;
3329                 }
3330
3331                 /*
3332                  * We do not want to return positive value from pm_runtime_get,
3333                  * there are many instances of devices calling spi_setup() and
3334                  * checking for a non-zero return value instead of a negative
3335                  * return value.
3336                  */
3337                 status = 0;
3338
3339                 spi_set_cs(spi, false);
3340                 pm_runtime_mark_last_busy(spi->controller->dev.parent);
3341                 pm_runtime_put_autosuspend(spi->controller->dev.parent);
3342         } else {
3343                 spi_set_cs(spi, false);
3344         }
3345
3346         if (spi->rt && !spi->controller->rt) {
3347                 spi->controller->rt = true;
3348                 spi_set_thread_rt(spi->controller);
3349         }
3350
3351         dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
3352                         (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
3353                         (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
3354                         (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
3355                         (spi->mode & SPI_3WIRE) ? "3wire, " : "",
3356                         (spi->mode & SPI_LOOP) ? "loopback, " : "",
3357                         spi->bits_per_word, spi->max_speed_hz,
3358                         status);
3359
3360         return status;
3361 }
3362 EXPORT_SYMBOL_GPL(spi_setup);
3363
3364 /**
3365  * spi_set_cs_timing - configure CS setup, hold, and inactive delays
3366  * @spi: the device that requires specific CS timing configuration
3367  * @setup: CS setup time specified via @spi_delay
3368  * @hold: CS hold time specified via @spi_delay
3369  * @inactive: CS inactive delay between transfers specified via @spi_delay
3370  *
3371  * Return: zero on success, else a negative error code.
3372  */
3373 int spi_set_cs_timing(struct spi_device *spi, struct spi_delay *setup,
3374                       struct spi_delay *hold, struct spi_delay *inactive)
3375 {
3376         size_t len;
3377
3378         if (spi->controller->set_cs_timing)
3379                 return spi->controller->set_cs_timing(spi, setup, hold,
3380                                                       inactive);
3381
3382         if ((setup && setup->unit == SPI_DELAY_UNIT_SCK) ||
3383             (hold && hold->unit == SPI_DELAY_UNIT_SCK) ||
3384             (inactive && inactive->unit == SPI_DELAY_UNIT_SCK)) {
3385                 dev_err(&spi->dev,
3386                         "Clock-cycle delays for CS not supported in SW mode\n");
3387                 return -ENOTSUPP;
3388         }
3389
3390         len = sizeof(struct spi_delay);
3391
3392         /* copy delays to controller */
3393         if (setup)
3394                 memcpy(&spi->controller->cs_setup, setup, len);
3395         else
3396                 memset(&spi->controller->cs_setup, 0, len);
3397
3398         if (hold)
3399                 memcpy(&spi->controller->cs_hold, hold, len);
3400         else
3401                 memset(&spi->controller->cs_hold, 0, len);
3402
3403         if (inactive)
3404                 memcpy(&spi->controller->cs_inactive, inactive, len);
3405         else
3406                 memset(&spi->controller->cs_inactive, 0, len);
3407
3408         return 0;
3409 }
3410 EXPORT_SYMBOL_GPL(spi_set_cs_timing);
3411
3412 static int _spi_xfer_word_delay_update(struct spi_transfer *xfer,
3413                                        struct spi_device *spi)
3414 {
3415         int delay1, delay2;
3416
3417         delay1 = spi_delay_to_ns(&xfer->word_delay, xfer);
3418         if (delay1 < 0)
3419                 return delay1;
3420
3421         delay2 = spi_delay_to_ns(&spi->word_delay, xfer);
3422         if (delay2 < 0)
3423                 return delay2;
3424
3425         if (delay1 < delay2)
3426                 memcpy(&xfer->word_delay, &spi->word_delay,
3427                        sizeof(xfer->word_delay));
3428
3429         return 0;
3430 }
3431
3432 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
3433 {
3434         struct spi_controller *ctlr = spi->controller;
3435         struct spi_transfer *xfer;
3436         int w_size;
3437
3438         if (list_empty(&message->transfers))
3439                 return -EINVAL;
3440
3441         /* If an SPI controller does not support toggling the CS line on each
3442          * transfer (indicated by the SPI_CS_WORD flag) or we are using a GPIO
3443          * for the CS line, we can emulate the CS-per-word hardware function by
3444          * splitting transfers into one-word transfers and ensuring that
3445          * cs_change is set for each transfer.
3446          */
3447         if ((spi->mode & SPI_CS_WORD) && (!(ctlr->mode_bits & SPI_CS_WORD) ||
3448                                           spi->cs_gpiod ||
3449                                           gpio_is_valid(spi->cs_gpio))) {
3450                 size_t maxsize;
3451                 int ret;
3452
3453                 maxsize = (spi->bits_per_word + 7) / 8;
3454
3455                 /* spi_split_transfers_maxsize() requires message->spi */
3456                 message->spi = spi;
3457
3458                 ret = spi_split_transfers_maxsize(ctlr, message, maxsize,
3459                                                   GFP_KERNEL);
3460                 if (ret)
3461                         return ret;
3462
3463                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3464                         /* don't change cs_change on the last entry in the list */
3465                         if (list_is_last(&xfer->transfer_list, &message->transfers))
3466                                 break;
3467                         xfer->cs_change = 1;
3468                 }
3469         }
3470
3471         /* Half-duplex links include original MicroWire, and ones with
3472          * only one data pin like SPI_3WIRE (switches direction) or where
3473          * either MOSI or MISO is missing.  They can also be caused by
3474          * software limitations.
3475          */
3476         if ((ctlr->flags & SPI_CONTROLLER_HALF_DUPLEX) ||
3477             (spi->mode & SPI_3WIRE)) {
3478                 unsigned flags = ctlr->flags;
3479
3480                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3481                         if (xfer->rx_buf && xfer->tx_buf)
3482                                 return -EINVAL;
3483                         if ((flags & SPI_CONTROLLER_NO_TX) && xfer->tx_buf)
3484                                 return -EINVAL;
3485                         if ((flags & SPI_CONTROLLER_NO_RX) && xfer->rx_buf)
3486                                 return -EINVAL;
3487                 }
3488         }
3489
3490         /**
3491          * Set transfer bits_per_word and max speed as spi device default if
3492          * it is not set for this transfer.
3493          * Set transfer tx_nbits and rx_nbits as single transfer default
3494          * (SPI_NBITS_SINGLE) if it is not set for this transfer.
3495          * Ensure transfer word_delay is at least as long as that required by
3496          * device itself.
3497          */
3498         message->frame_length = 0;
3499         list_for_each_entry(xfer, &message->transfers, transfer_list) {
3500                 xfer->effective_speed_hz = 0;
3501                 message->frame_length += xfer->len;
3502                 if (!xfer->bits_per_word)
3503                         xfer->bits_per_word = spi->bits_per_word;
3504
3505                 if (!xfer->speed_hz)
3506                         xfer->speed_hz = spi->max_speed_hz;
3507
3508                 if (ctlr->max_speed_hz && xfer->speed_hz > ctlr->max_speed_hz)
3509                         xfer->speed_hz = ctlr->max_speed_hz;
3510
3511                 if (__spi_validate_bits_per_word(ctlr, xfer->bits_per_word))
3512                         return -EINVAL;
3513
3514                 /*
3515                  * SPI transfer length should be multiple of SPI word size
3516                  * where SPI word size should be power-of-two multiple
3517                  */
3518                 if (xfer->bits_per_word <= 8)
3519                         w_size = 1;
3520                 else if (xfer->bits_per_word <= 16)
3521                         w_size = 2;
3522                 else
3523                         w_size = 4;
3524
3525                 /* No partial transfers accepted */
3526                 if (xfer->len % w_size)
3527                         return -EINVAL;
3528
3529                 if (xfer->speed_hz && ctlr->min_speed_hz &&
3530                     xfer->speed_hz < ctlr->min_speed_hz)
3531                         return -EINVAL;
3532
3533                 if (xfer->tx_buf && !xfer->tx_nbits)
3534                         xfer->tx_nbits = SPI_NBITS_SINGLE;
3535                 if (xfer->rx_buf && !xfer->rx_nbits)
3536                         xfer->rx_nbits = SPI_NBITS_SINGLE;
3537                 /* check transfer tx/rx_nbits:
3538                  * 1. check the value matches one of single, dual and quad
3539                  * 2. check tx/rx_nbits match the mode in spi_device
3540                  */
3541                 if (xfer->tx_buf) {
3542                         if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
3543                                 xfer->tx_nbits != SPI_NBITS_DUAL &&
3544                                 xfer->tx_nbits != SPI_NBITS_QUAD)
3545                                 return -EINVAL;
3546                         if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
3547                                 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
3548                                 return -EINVAL;
3549                         if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
3550                                 !(spi->mode & SPI_TX_QUAD))
3551                                 return -EINVAL;
3552                 }
3553                 /* check transfer rx_nbits */
3554                 if (xfer->rx_buf) {
3555                         if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
3556                                 xfer->rx_nbits != SPI_NBITS_DUAL &&
3557                                 xfer->rx_nbits != SPI_NBITS_QUAD)
3558                                 return -EINVAL;
3559                         if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
3560                                 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
3561                                 return -EINVAL;
3562                         if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
3563                                 !(spi->mode & SPI_RX_QUAD))
3564                                 return -EINVAL;
3565                 }
3566
3567                 if (_spi_xfer_word_delay_update(xfer, spi))
3568                         return -EINVAL;
3569         }
3570
3571         message->status = -EINPROGRESS;
3572
3573         return 0;
3574 }
3575
3576 static int __spi_async(struct spi_device *spi, struct spi_message *message)
3577 {
3578         struct spi_controller *ctlr = spi->controller;
3579         struct spi_transfer *xfer;
3580
3581         /*
3582          * Some controllers do not support doing regular SPI transfers. Return
3583          * ENOTSUPP when this is the case.
3584          */
3585         if (!ctlr->transfer)
3586                 return -ENOTSUPP;
3587
3588         message->spi = spi;
3589
3590         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_async);
3591         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
3592
3593         trace_spi_message_submit(message);
3594
3595         if (!ctlr->ptp_sts_supported) {
3596                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3597                         xfer->ptp_sts_word_pre = 0;
3598                         ptp_read_system_prets(xfer->ptp_sts);
3599                 }
3600         }
3601
3602         return ctlr->transfer(spi, message);
3603 }
3604
3605 /**
3606  * spi_async - asynchronous SPI transfer
3607  * @spi: device with which data will be exchanged
3608  * @message: describes the data transfers, including completion callback
3609  * Context: any (irqs may be blocked, etc)
3610  *
3611  * This call may be used in_irq and other contexts which can't sleep,
3612  * as well as from task contexts which can sleep.
3613  *
3614  * The completion callback is invoked in a context which can't sleep.
3615  * Before that invocation, the value of message->status is undefined.
3616  * When the callback is issued, message->status holds either zero (to
3617  * indicate complete success) or a negative error code.  After that
3618  * callback returns, the driver which issued the transfer request may
3619  * deallocate the associated memory; it's no longer in use by any SPI
3620  * core or controller driver code.
3621  *
3622  * Note that although all messages to a spi_device are handled in
3623  * FIFO order, messages may go to different devices in other orders.
3624  * Some device might be higher priority, or have various "hard" access
3625  * time requirements, for example.
3626  *
3627  * On detection of any fault during the transfer, processing of
3628  * the entire message is aborted, and the device is deselected.
3629  * Until returning from the associated message completion callback,
3630  * no other spi_message queued to that device will be processed.
3631  * (This rule applies equally to all the synchronous transfer calls,
3632  * which are wrappers around this core asynchronous primitive.)
3633  *
3634  * Return: zero on success, else a negative error code.
3635  */
3636 int spi_async(struct spi_device *spi, struct spi_message *message)
3637 {
3638         struct spi_controller *ctlr = spi->controller;
3639         int ret;
3640         unsigned long flags;
3641
3642         ret = __spi_validate(spi, message);
3643         if (ret != 0)
3644                 return ret;
3645
3646         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3647
3648         if (ctlr->bus_lock_flag)
3649                 ret = -EBUSY;
3650         else
3651                 ret = __spi_async(spi, message);
3652
3653         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3654
3655         return ret;
3656 }
3657 EXPORT_SYMBOL_GPL(spi_async);
3658
3659 /**
3660  * spi_async_locked - version of spi_async with exclusive bus usage
3661  * @spi: device with which data will be exchanged
3662  * @message: describes the data transfers, including completion callback
3663  * Context: any (irqs may be blocked, etc)
3664  *
3665  * This call may be used in_irq and other contexts which can't sleep,
3666  * as well as from task contexts which can sleep.
3667  *
3668  * The completion callback is invoked in a context which can't sleep.
3669  * Before that invocation, the value of message->status is undefined.
3670  * When the callback is issued, message->status holds either zero (to
3671  * indicate complete success) or a negative error code.  After that
3672  * callback returns, the driver which issued the transfer request may
3673  * deallocate the associated memory; it's no longer in use by any SPI
3674  * core or controller driver code.
3675  *
3676  * Note that although all messages to a spi_device are handled in
3677  * FIFO order, messages may go to different devices in other orders.
3678  * Some device might be higher priority, or have various "hard" access
3679  * time requirements, for example.
3680  *
3681  * On detection of any fault during the transfer, processing of
3682  * the entire message is aborted, and the device is deselected.
3683  * Until returning from the associated message completion callback,
3684  * no other spi_message queued to that device will be processed.
3685  * (This rule applies equally to all the synchronous transfer calls,
3686  * which are wrappers around this core asynchronous primitive.)
3687  *
3688  * Return: zero on success, else a negative error code.
3689  */
3690 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
3691 {
3692         struct spi_controller *ctlr = spi->controller;
3693         int ret;
3694         unsigned long flags;
3695
3696         ret = __spi_validate(spi, message);
3697         if (ret != 0)
3698                 return ret;
3699
3700         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3701
3702         ret = __spi_async(spi, message);
3703
3704         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3705
3706         return ret;
3707
3708 }
3709 EXPORT_SYMBOL_GPL(spi_async_locked);
3710
3711 /*-------------------------------------------------------------------------*/
3712
3713 /* Utility methods for SPI protocol drivers, layered on
3714  * top of the core.  Some other utility methods are defined as
3715  * inline functions.
3716  */
3717
3718 static void spi_complete(void *arg)
3719 {
3720         complete(arg);
3721 }
3722
3723 static int __spi_sync(struct spi_device *spi, struct spi_message *message)
3724 {
3725         DECLARE_COMPLETION_ONSTACK(done);
3726         int status;
3727         struct spi_controller *ctlr = spi->controller;
3728         unsigned long flags;
3729
3730         status = __spi_validate(spi, message);
3731         if (status != 0)
3732                 return status;
3733
3734         message->complete = spi_complete;
3735         message->context = &done;
3736         message->spi = spi;
3737
3738         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_sync);
3739         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
3740
3741         /* If we're not using the legacy transfer method then we will
3742          * try to transfer in the calling context so special case.
3743          * This code would be less tricky if we could remove the
3744          * support for driver implemented message queues.
3745          */
3746         if (ctlr->transfer == spi_queued_transfer) {
3747                 spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3748
3749                 trace_spi_message_submit(message);
3750
3751                 status = __spi_queued_transfer(spi, message, false);
3752
3753                 spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3754         } else {
3755                 status = spi_async_locked(spi, message);
3756         }
3757
3758         if (status == 0) {
3759                 /* Push out the messages in the calling context if we
3760                  * can.
3761                  */
3762                 if (ctlr->transfer == spi_queued_transfer) {
3763                         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
3764                                                        spi_sync_immediate);
3765                         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
3766                                                        spi_sync_immediate);
3767                         __spi_pump_messages(ctlr, false);
3768                 }
3769
3770                 wait_for_completion(&done);
3771                 status = message->status;
3772         }
3773         message->context = NULL;
3774         return status;
3775 }
3776
3777 /**
3778  * spi_sync - blocking/synchronous SPI data transfers
3779  * @spi: device with which data will be exchanged
3780  * @message: describes the data transfers
3781  * Context: can sleep
3782  *
3783  * This call may only be used from a context that may sleep.  The sleep
3784  * is non-interruptible, and has no timeout.  Low-overhead controller
3785  * drivers may DMA directly into and out of the message buffers.
3786  *
3787  * Note that the SPI device's chip select is active during the message,
3788  * and then is normally disabled between messages.  Drivers for some
3789  * frequently-used devices may want to minimize costs of selecting a chip,
3790  * by leaving it selected in anticipation that the next message will go
3791  * to the same chip.  (That may increase power usage.)
3792  *
3793  * Also, the caller is guaranteeing that the memory associated with the
3794  * message will not be freed before this call returns.
3795  *
3796  * Return: zero on success, else a negative error code.
3797  */
3798 int spi_sync(struct spi_device *spi, struct spi_message *message)
3799 {
3800         int ret;
3801
3802         mutex_lock(&spi->controller->bus_lock_mutex);
3803         ret = __spi_sync(spi, message);
3804         mutex_unlock(&spi->controller->bus_lock_mutex);
3805
3806         return ret;
3807 }
3808 EXPORT_SYMBOL_GPL(spi_sync);
3809
3810 /**
3811  * spi_sync_locked - version of spi_sync with exclusive bus usage
3812  * @spi: device with which data will be exchanged
3813  * @message: describes the data transfers
3814  * Context: can sleep
3815  *
3816  * This call may only be used from a context that may sleep.  The sleep
3817  * is non-interruptible, and has no timeout.  Low-overhead controller
3818  * drivers may DMA directly into and out of the message buffers.
3819  *
3820  * This call should be used by drivers that require exclusive access to the
3821  * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
3822  * be released by a spi_bus_unlock call when the exclusive access is over.
3823  *
3824  * Return: zero on success, else a negative error code.
3825  */
3826 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
3827 {
3828         return __spi_sync(spi, message);
3829 }
3830 EXPORT_SYMBOL_GPL(spi_sync_locked);
3831
3832 /**
3833  * spi_bus_lock - obtain a lock for exclusive SPI bus usage
3834  * @ctlr: SPI bus master that should be locked for exclusive bus access
3835  * Context: can sleep
3836  *
3837  * This call may only be used from a context that may sleep.  The sleep
3838  * is non-interruptible, and has no timeout.
3839  *
3840  * This call should be used by drivers that require exclusive access to the
3841  * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
3842  * exclusive access is over. Data transfer must be done by spi_sync_locked
3843  * and spi_async_locked calls when the SPI bus lock is held.
3844  *
3845  * Return: always zero.
3846  */
3847 int spi_bus_lock(struct spi_controller *ctlr)
3848 {
3849         unsigned long flags;
3850
3851         mutex_lock(&ctlr->bus_lock_mutex);
3852
3853         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3854         ctlr->bus_lock_flag = 1;
3855         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3856
3857         /* mutex remains locked until spi_bus_unlock is called */
3858
3859         return 0;
3860 }
3861 EXPORT_SYMBOL_GPL(spi_bus_lock);
3862
3863 /**
3864  * spi_bus_unlock - release the lock for exclusive SPI bus usage
3865  * @ctlr: SPI bus master that was locked for exclusive bus access
3866  * Context: can sleep
3867  *
3868  * This call may only be used from a context that may sleep.  The sleep
3869  * is non-interruptible, and has no timeout.
3870  *
3871  * This call releases an SPI bus lock previously obtained by an spi_bus_lock
3872  * call.
3873  *
3874  * Return: always zero.
3875  */
3876 int spi_bus_unlock(struct spi_controller *ctlr)
3877 {
3878         ctlr->bus_lock_flag = 0;
3879
3880         mutex_unlock(&ctlr->bus_lock_mutex);
3881
3882         return 0;
3883 }
3884 EXPORT_SYMBOL_GPL(spi_bus_unlock);
3885
3886 /* portable code must never pass more than 32 bytes */
3887 #define SPI_BUFSIZ      max(32, SMP_CACHE_BYTES)
3888
3889 static u8       *buf;
3890
3891 /**
3892  * spi_write_then_read - SPI synchronous write followed by read
3893  * @spi: device with which data will be exchanged
3894  * @txbuf: data to be written (need not be dma-safe)
3895  * @n_tx: size of txbuf, in bytes
3896  * @rxbuf: buffer into which data will be read (need not be dma-safe)
3897  * @n_rx: size of rxbuf, in bytes
3898  * Context: can sleep
3899  *
3900  * This performs a half duplex MicroWire style transaction with the
3901  * device, sending txbuf and then reading rxbuf.  The return value
3902  * is zero for success, else a negative errno status code.
3903  * This call may only be used from a context that may sleep.
3904  *
3905  * Parameters to this routine are always copied using a small buffer.
3906  * Performance-sensitive or bulk transfer code should instead use
3907  * spi_{async,sync}() calls with dma-safe buffers.
3908  *
3909  * Return: zero on success, else a negative error code.
3910  */
3911 int spi_write_then_read(struct spi_device *spi,
3912                 const void *txbuf, unsigned n_tx,
3913                 void *rxbuf, unsigned n_rx)
3914 {
3915         static DEFINE_MUTEX(lock);
3916
3917         int                     status;
3918         struct spi_message      message;
3919         struct spi_transfer     x[2];
3920         u8                      *local_buf;
3921
3922         /* Use preallocated DMA-safe buffer if we can.  We can't avoid
3923          * copying here, (as a pure convenience thing), but we can
3924          * keep heap costs out of the hot path unless someone else is
3925          * using the pre-allocated buffer or the transfer is too large.
3926          */
3927         if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
3928                 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
3929                                     GFP_KERNEL | GFP_DMA);
3930                 if (!local_buf)
3931                         return -ENOMEM;
3932         } else {
3933                 local_buf = buf;
3934         }
3935
3936         spi_message_init(&message);
3937         memset(x, 0, sizeof(x));
3938         if (n_tx) {
3939                 x[0].len = n_tx;
3940                 spi_message_add_tail(&x[0], &message);
3941         }
3942         if (n_rx) {
3943                 x[1].len = n_rx;
3944                 spi_message_add_tail(&x[1], &message);
3945         }
3946
3947         memcpy(local_buf, txbuf, n_tx);
3948         x[0].tx_buf = local_buf;
3949         x[1].rx_buf = local_buf + n_tx;
3950
3951         /* do the i/o */
3952         status = spi_sync(spi, &message);
3953         if (status == 0)
3954                 memcpy(rxbuf, x[1].rx_buf, n_rx);
3955
3956         if (x[0].tx_buf == buf)
3957                 mutex_unlock(&lock);
3958         else
3959                 kfree(local_buf);
3960
3961         return status;
3962 }
3963 EXPORT_SYMBOL_GPL(spi_write_then_read);
3964
3965 /*-------------------------------------------------------------------------*/
3966
3967 #if IS_ENABLED(CONFIG_OF)
3968 /* must call put_device() when done with returned spi_device device */
3969 struct spi_device *of_find_spi_device_by_node(struct device_node *node)
3970 {
3971         struct device *dev = bus_find_device_by_of_node(&spi_bus_type, node);
3972
3973         return dev ? to_spi_device(dev) : NULL;
3974 }
3975 EXPORT_SYMBOL_GPL(of_find_spi_device_by_node);
3976 #endif /* IS_ENABLED(CONFIG_OF) */
3977
3978 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
3979 /* the spi controllers are not using spi_bus, so we find it with another way */
3980 static struct spi_controller *of_find_spi_controller_by_node(struct device_node *node)
3981 {
3982         struct device *dev;
3983
3984         dev = class_find_device_by_of_node(&spi_master_class, node);
3985         if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
3986                 dev = class_find_device_by_of_node(&spi_slave_class, node);
3987         if (!dev)
3988                 return NULL;
3989
3990         /* reference got in class_find_device */
3991         return container_of(dev, struct spi_controller, dev);
3992 }
3993
3994 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
3995                          void *arg)
3996 {
3997         struct of_reconfig_data *rd = arg;
3998         struct spi_controller *ctlr;
3999         struct spi_device *spi;
4000
4001         switch (of_reconfig_get_state_change(action, arg)) {
4002         case OF_RECONFIG_CHANGE_ADD:
4003                 ctlr = of_find_spi_controller_by_node(rd->dn->parent);
4004                 if (ctlr == NULL)
4005                         return NOTIFY_OK;       /* not for us */
4006
4007                 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
4008                         put_device(&ctlr->dev);
4009                         return NOTIFY_OK;
4010                 }
4011
4012                 spi = of_register_spi_device(ctlr, rd->dn);
4013                 put_device(&ctlr->dev);
4014
4015                 if (IS_ERR(spi)) {
4016                         pr_err("%s: failed to create for '%pOF'\n",
4017                                         __func__, rd->dn);
4018                         of_node_clear_flag(rd->dn, OF_POPULATED);
4019                         return notifier_from_errno(PTR_ERR(spi));
4020                 }
4021                 break;
4022
4023         case OF_RECONFIG_CHANGE_REMOVE:
4024                 /* already depopulated? */
4025                 if (!of_node_check_flag(rd->dn, OF_POPULATED))
4026                         return NOTIFY_OK;
4027
4028                 /* find our device by node */
4029                 spi = of_find_spi_device_by_node(rd->dn);
4030                 if (spi == NULL)
4031                         return NOTIFY_OK;       /* no? not meant for us */
4032
4033                 /* unregister takes one ref away */
4034                 spi_unregister_device(spi);
4035
4036                 /* and put the reference of the find */
4037                 put_device(&spi->dev);
4038                 break;
4039         }
4040
4041         return NOTIFY_OK;
4042 }
4043
4044 static struct notifier_block spi_of_notifier = {
4045         .notifier_call = of_spi_notify,
4046 };
4047 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
4048 extern struct notifier_block spi_of_notifier;
4049 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
4050
4051 #if IS_ENABLED(CONFIG_ACPI)
4052 static int spi_acpi_controller_match(struct device *dev, const void *data)
4053 {
4054         return ACPI_COMPANION(dev->parent) == data;
4055 }
4056
4057 static struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev)
4058 {
4059         struct device *dev;
4060
4061         dev = class_find_device(&spi_master_class, NULL, adev,
4062                                 spi_acpi_controller_match);
4063         if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
4064                 dev = class_find_device(&spi_slave_class, NULL, adev,
4065                                         spi_acpi_controller_match);
4066         if (!dev)
4067                 return NULL;
4068
4069         return container_of(dev, struct spi_controller, dev);
4070 }
4071
4072 static struct spi_device *acpi_spi_find_device_by_adev(struct acpi_device *adev)
4073 {
4074         struct device *dev;
4075
4076         dev = bus_find_device_by_acpi_dev(&spi_bus_type, adev);
4077         return to_spi_device(dev);
4078 }
4079
4080 static int acpi_spi_notify(struct notifier_block *nb, unsigned long value,
4081                            void *arg)
4082 {
4083         struct acpi_device *adev = arg;
4084         struct spi_controller *ctlr;
4085         struct spi_device *spi;
4086
4087         switch (value) {
4088         case ACPI_RECONFIG_DEVICE_ADD:
4089                 ctlr = acpi_spi_find_controller_by_adev(adev->parent);
4090                 if (!ctlr)
4091                         break;
4092
4093                 acpi_register_spi_device(ctlr, adev);
4094                 put_device(&ctlr->dev);
4095                 break;
4096         case ACPI_RECONFIG_DEVICE_REMOVE:
4097                 if (!acpi_device_enumerated(adev))
4098                         break;
4099
4100                 spi = acpi_spi_find_device_by_adev(adev);
4101                 if (!spi)
4102                         break;
4103
4104                 spi_unregister_device(spi);
4105                 put_device(&spi->dev);
4106                 break;
4107         }
4108
4109         return NOTIFY_OK;
4110 }
4111
4112 static struct notifier_block spi_acpi_notifier = {
4113         .notifier_call = acpi_spi_notify,
4114 };
4115 #else
4116 extern struct notifier_block spi_acpi_notifier;
4117 #endif
4118
4119 static int __init spi_init(void)
4120 {
4121         int     status;
4122
4123         buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
4124         if (!buf) {
4125                 status = -ENOMEM;
4126                 goto err0;
4127         }
4128
4129         status = bus_register(&spi_bus_type);
4130         if (status < 0)
4131                 goto err1;
4132
4133         status = class_register(&spi_master_class);
4134         if (status < 0)
4135                 goto err2;
4136
4137         if (IS_ENABLED(CONFIG_SPI_SLAVE)) {
4138                 status = class_register(&spi_slave_class);
4139                 if (status < 0)
4140                         goto err3;
4141         }
4142
4143         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
4144                 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
4145         if (IS_ENABLED(CONFIG_ACPI))
4146                 WARN_ON(acpi_reconfig_notifier_register(&spi_acpi_notifier));
4147
4148         return 0;
4149
4150 err3:
4151         class_unregister(&spi_master_class);
4152 err2:
4153         bus_unregister(&spi_bus_type);
4154 err1:
4155         kfree(buf);
4156         buf = NULL;
4157 err0:
4158         return status;
4159 }
4160
4161 /* board_info is normally registered in arch_initcall(),
4162  * but even essential drivers wait till later
4163  *
4164  * REVISIT only boardinfo really needs static linking. the rest (device and
4165  * driver registration) _could_ be dynamically linked (modular) ... costs
4166  * include needing to have boardinfo data structures be much more public.
4167  */
4168 postcore_initcall(spi_init);