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