drivers/spi/spi.c

   1 /*
   2  * SPI init/core code
   3  *
   4  * Copyright (C) 2005 David Brownell
   5  * Copyright (C) 2008 Secret Lab Technologies Ltd.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  */
  17
  18 #include <linux/kernel.h>
  19 #include <linux/device.h>
  20 #include <linux/init.h>
  21 #include <linux/cache.h>
  22 #include <linux/dma-mapping.h>
  23 #include <linux/dmaengine.h>
  24 #include <linux/mutex.h>
  25 #include <linux/of_device.h>
  26 #include <linux/of_irq.h>
  27 #include <linux/clk/clk-conf.h>
  28 #include <linux/slab.h>
  29 #include <linux/mod_devicetable.h>
  30 #include <linux/spi/spi.h>
  31 #include <linux/of_gpio.h>
  32 #include <linux/pm_runtime.h>
  33 #include <linux/pm_domain.h>
  34 #include <linux/property.h>
  35 #include <linux/export.h>
  36 #include <linux/sched/rt.h>
  37 #include <uapi/linux/sched/types.h>
  38 #include <linux/delay.h>
  39 #include <linux/kthread.h>
  40 #include <linux/ioport.h>
  41 #include <linux/acpi.h>
  42 #include <linux/highmem.h>
  43 #include <linux/idr.h>
  44 #include <linux/platform_data/x86/apple.h>
  45
  46 #define CREATE_TRACE_POINTS
  47 #include <trace/events/spi.h>
  48
  49 static DEFINE_IDR(spi_master_idr);
  50
  51 static void spidev_release(struct device *dev)
  52 {
  53         struct spi_device       *spi = to_spi_device(dev);
  54
  55         /* spi controllers may cleanup for released devices */
  56         if (spi->controller->cleanup)
  57                 spi->controller->cleanup(spi);
  58
  59         spi_controller_put(spi->controller);
  60         kfree(spi);
  61 }
  62
  63 static ssize_t
  64 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
  65 {
  66         const struct spi_device *spi = to_spi_device(dev);
  67         int len;
  68
  69         len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
  70         if (len != -ENODEV)
  71                 return len;
  72
  73         return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
  74 }
  75 static DEVICE_ATTR_RO(modalias);
  76
  77 #define SPI_STATISTICS_ATTRS(field, file)                               \
  78 static ssize_t spi_controller_##field##_show(struct device *dev,        \
  79                                              struct device_attribute *attr, \
  80                                              char *buf)                 \
  81 {                                                                       \
  82         struct spi_controller *ctlr = container_of(dev,                 \
  83                                          struct spi_controller, dev);   \
  84         return spi_statistics_##field##_show(&ctlr->statistics, buf);   \
  85 }                                                                       \
  86 static struct device_attribute dev_attr_spi_controller_##field = {      \
  87         .attr = { .name = file, .mode = 0444 },                         \
  88         .show = spi_controller_##field##_show,                          \
  89 };                                                                      \
  90 static ssize_t spi_device_##field##_show(struct device *dev,            \
  91                                          struct device_attribute *attr, \
  92                                         char *buf)                      \
  93 {                                                                       \
  94         struct spi_device *spi = to_spi_device(dev);                    \
  95         return spi_statistics_##field##_show(&spi->statistics, buf);    \
  96 }                                                                       \
  97 static struct device_attribute dev_attr_spi_device_##field = {          \
  98         .attr = { .name = file, .mode = 0444 },                         \
  99         .show = spi_device_##field##_show,                              \
 100 }
 101
 102 #define SPI_STATISTICS_SHOW_NAME(name, file, field, format_string)      \
 103 static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
 104                                             char *buf)                  \
 105 {                                                                       \
 106         unsigned long flags;                                            \
 107         ssize_t len;                                                    \
 108         spin_lock_irqsave(&stat->lock, flags);                          \
 109         len = sprintf(buf, format_string, stat->field);                 \
 110         spin_unlock_irqrestore(&stat->lock, flags);                     \
 111         return len;                                                     \
 112 }                                                                       \
 113 SPI_STATISTICS_ATTRS(name, file)
 114
 115 #define SPI_STATISTICS_SHOW(field, format_string)                       \
 116         SPI_STATISTICS_SHOW_NAME(field, __stringify(field),             \
 117                                  field, format_string)
 118
 119 SPI_STATISTICS_SHOW(messages, "%lu");
 120 SPI_STATISTICS_SHOW(transfers, "%lu");
 121 SPI_STATISTICS_SHOW(errors, "%lu");
 122 SPI_STATISTICS_SHOW(timedout, "%lu");
 123
 124 SPI_STATISTICS_SHOW(spi_sync, "%lu");
 125 SPI_STATISTICS_SHOW(spi_sync_immediate, "%lu");
 126 SPI_STATISTICS_SHOW(spi_async, "%lu");
 127
 128 SPI_STATISTICS_SHOW(bytes, "%llu");
 129 SPI_STATISTICS_SHOW(bytes_rx, "%llu");
 130 SPI_STATISTICS_SHOW(bytes_tx, "%llu");
 131
 132 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number)              \
 133         SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index,           \
 134                                  "transfer_bytes_histo_" number,        \
 135                                  transfer_bytes_histo[index],  "%lu")
 136 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0,  "0-1");
 137 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1,  "2-3");
 138 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2,  "4-7");
 139 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3,  "8-15");
 140 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4,  "16-31");
 141 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5,  "32-63");
 142 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6,  "64-127");
 143 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7,  "128-255");
 144 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8,  "256-511");
 145 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9,  "512-1023");
 146 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
 147 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
 148 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
 149 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
 150 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
 151 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
 152 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
 153
 154 SPI_STATISTICS_SHOW(transfers_split_maxsize, "%lu");
 155
 156 static struct attribute *spi_dev_attrs[] = {
 157         &dev_attr_modalias.attr,
 158         NULL,
 159 };
 160
 161 static const struct attribute_group spi_dev_group = {
 162         .attrs  = spi_dev_attrs,
 163 };
 164
 165 static struct attribute *spi_device_statistics_attrs[] = {
 166         &dev_attr_spi_device_messages.attr,
 167         &dev_attr_spi_device_transfers.attr,
 168         &dev_attr_spi_device_errors.attr,
 169         &dev_attr_spi_device_timedout.attr,
 170         &dev_attr_spi_device_spi_sync.attr,
 171         &dev_attr_spi_device_spi_sync_immediate.attr,
 172         &dev_attr_spi_device_spi_async.attr,
 173         &dev_attr_spi_device_bytes.attr,
 174         &dev_attr_spi_device_bytes_rx.attr,
 175         &dev_attr_spi_device_bytes_tx.attr,
 176         &dev_attr_spi_device_transfer_bytes_histo0.attr,
 177         &dev_attr_spi_device_transfer_bytes_histo1.attr,
 178         &dev_attr_spi_device_transfer_bytes_histo2.attr,
 179         &dev_attr_spi_device_transfer_bytes_histo3.attr,
 180         &dev_attr_spi_device_transfer_bytes_histo4.attr,
 181         &dev_attr_spi_device_transfer_bytes_histo5.attr,
 182         &dev_attr_spi_device_transfer_bytes_histo6.attr,
 183         &dev_attr_spi_device_transfer_bytes_histo7.attr,
 184         &dev_attr_spi_device_transfer_bytes_histo8.attr,
 185         &dev_attr_spi_device_transfer_bytes_histo9.attr,
 186         &dev_attr_spi_device_transfer_bytes_histo10.attr,
 187         &dev_attr_spi_device_transfer_bytes_histo11.attr,
 188         &dev_attr_spi_device_transfer_bytes_histo12.attr,
 189         &dev_attr_spi_device_transfer_bytes_histo13.attr,
 190         &dev_attr_spi_device_transfer_bytes_histo14.attr,
 191         &dev_attr_spi_device_transfer_bytes_histo15.attr,
 192         &dev_attr_spi_device_transfer_bytes_histo16.attr,
 193         &dev_attr_spi_device_transfers_split_maxsize.attr,
 194         NULL,
 195 };
 196
 197 static const struct attribute_group spi_device_statistics_group = {
 198         .name  = "statistics",
 199         .attrs  = spi_device_statistics_attrs,
 200 };
 201
 202 static const struct attribute_group *spi_dev_groups[] = {
 203         &spi_dev_group,
 204         &spi_device_statistics_group,
 205         NULL,
 206 };
 207
 208 static struct attribute *spi_controller_statistics_attrs[] = {
 209         &dev_attr_spi_controller_messages.attr,
 210         &dev_attr_spi_controller_transfers.attr,
 211         &dev_attr_spi_controller_errors.attr,
 212         &dev_attr_spi_controller_timedout.attr,
 213         &dev_attr_spi_controller_spi_sync.attr,
 214         &dev_attr_spi_controller_spi_sync_immediate.attr,
 215         &dev_attr_spi_controller_spi_async.attr,
 216         &dev_attr_spi_controller_bytes.attr,
 217         &dev_attr_spi_controller_bytes_rx.attr,
 218         &dev_attr_spi_controller_bytes_tx.attr,
 219         &dev_attr_spi_controller_transfer_bytes_histo0.attr,
 220         &dev_attr_spi_controller_transfer_bytes_histo1.attr,
 221         &dev_attr_spi_controller_transfer_bytes_histo2.attr,
 222         &dev_attr_spi_controller_transfer_bytes_histo3.attr,
 223         &dev_attr_spi_controller_transfer_bytes_histo4.attr,
 224         &dev_attr_spi_controller_transfer_bytes_histo5.attr,
 225         &dev_attr_spi_controller_transfer_bytes_histo6.attr,
 226         &dev_attr_spi_controller_transfer_bytes_histo7.attr,
 227         &dev_attr_spi_controller_transfer_bytes_histo8.attr,
 228         &dev_attr_spi_controller_transfer_bytes_histo9.attr,
 229         &dev_attr_spi_controller_transfer_bytes_histo10.attr,
 230         &dev_attr_spi_controller_transfer_bytes_histo11.attr,
 231         &dev_attr_spi_controller_transfer_bytes_histo12.attr,
 232         &dev_attr_spi_controller_transfer_bytes_histo13.attr,
 233         &dev_attr_spi_controller_transfer_bytes_histo14.attr,
 234         &dev_attr_spi_controller_transfer_bytes_histo15.attr,
 235         &dev_attr_spi_controller_transfer_bytes_histo16.attr,
 236         &dev_attr_spi_controller_transfers_split_maxsize.attr,
 237         NULL,
 238 };
 239
 240 static const struct attribute_group spi_controller_statistics_group = {
 241         .name  = "statistics",
 242         .attrs  = spi_controller_statistics_attrs,
 243 };
 244
 245 static const struct attribute_group *spi_master_groups[] = {
 246         &spi_controller_statistics_group,
 247         NULL,
 248 };
 249
 250 void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
 251                                        struct spi_transfer *xfer,
 252                                        struct spi_controller *ctlr)
 253 {
 254         unsigned long flags;
 255         int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
 256
 257         if (l2len < 0)
 258                 l2len = 0;
 259
 260         spin_lock_irqsave(&stats->lock, flags);
 261
 262         stats->transfers++;
 263         stats->transfer_bytes_histo[l2len]++;
 264
 265         stats->bytes += xfer->len;
 266         if ((xfer->tx_buf) &&
 267             (xfer->tx_buf != ctlr->dummy_tx))
 268                 stats->bytes_tx += xfer->len;
 269         if ((xfer->rx_buf) &&
 270             (xfer->rx_buf != ctlr->dummy_rx))
 271                 stats->bytes_rx += xfer->len;
 272
 273         spin_unlock_irqrestore(&stats->lock, flags);
 274 }
 275 EXPORT_SYMBOL_GPL(spi_statistics_add_transfer_stats);
 276
 277 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
 278  * and the sysfs version makes coldplug work too.
 279  */
 280
 281 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
 282                                                 const struct spi_device *sdev)
 283 {
 284         while (id->name[0]) {
 285                 if (!strcmp(sdev->modalias, id->name))
 286                         return id;
 287                 id++;
 288         }
 289         return NULL;
 290 }
 291
 292 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
 293 {
 294         const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
 295
 296         return spi_match_id(sdrv->id_table, sdev);
 297 }
 298 EXPORT_SYMBOL_GPL(spi_get_device_id);
 299
 300 static int spi_match_device(struct device *dev, struct device_driver *drv)
 301 {
 302         const struct spi_device *spi = to_spi_device(dev);
 303         const struct spi_driver *sdrv = to_spi_driver(drv);
 304
 305         /* Attempt an OF style match */
 306         if (of_driver_match_device(dev, drv))
 307                 return 1;
 308
 309         /* Then try ACPI */
 310         if (acpi_driver_match_device(dev, drv))
 311                 return 1;
 312
 313         if (sdrv->id_table)
 314                 return !!spi_match_id(sdrv->id_table, spi);
 315
 316         return strcmp(spi->modalias, drv->name) == 0;
 317 }
 318
 319 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
 320 {
 321         const struct spi_device         *spi = to_spi_device(dev);
 322         int rc;
 323
 324         rc = acpi_device_uevent_modalias(dev, env);
 325         if (rc != -ENODEV)
 326                 return rc;
 327
 328         return add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
 329 }
 330
 331 struct bus_type spi_bus_type = {
 332         .name           = "spi",
 333         .dev_groups     = spi_dev_groups,
 334         .match          = spi_match_device,
 335         .uevent         = spi_uevent,
 336 };
 337 EXPORT_SYMBOL_GPL(spi_bus_type);
 338
 339
 340 static int spi_drv_probe(struct device *dev)
 341 {
 342         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 343         struct spi_device               *spi = to_spi_device(dev);
 344         int ret;
 345
 346         ret = of_clk_set_defaults(dev->of_node, false);
 347         if (ret)
 348                 return ret;
 349
 350         if (dev->of_node) {
 351                 spi->irq = of_irq_get(dev->of_node, 0);
 352                 if (spi->irq == -EPROBE_DEFER)
 353                         return -EPROBE_DEFER;
 354                 if (spi->irq < 0)
 355                         spi->irq = 0;
 356         }
 357
 358         ret = dev_pm_domain_attach(dev, true);
 359         if (ret != -EPROBE_DEFER) {
 360                 ret = sdrv->probe(spi);
 361                 if (ret)
 362                         dev_pm_domain_detach(dev, true);
 363         }
 364
 365         return ret;
 366 }
 367
 368 static int spi_drv_remove(struct device *dev)
 369 {
 370         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 371         int ret;
 372
 373         ret = sdrv->remove(to_spi_device(dev));
 374         dev_pm_domain_detach(dev, true);
 375
 376         return ret;
 377 }
 378
 379 static void spi_drv_shutdown(struct device *dev)
 380 {
 381         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 382
 383         sdrv->shutdown(to_spi_device(dev));
 384 }
 385
 386 /**
 387  * __spi_register_driver - register a SPI driver
 388  * @owner: owner module of the driver to register
 389  * @sdrv: the driver to register
 390  * Context: can sleep
 391  *
 392  * Return: zero on success, else a negative error code.
 393  */
 394 int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
 395 {
 396         sdrv->driver.owner = owner;
 397         sdrv->driver.bus = &spi_bus_type;
 398         if (sdrv->probe)
 399                 sdrv->driver.probe = spi_drv_probe;
 400         if (sdrv->remove)
 401                 sdrv->driver.remove = spi_drv_remove;
 402         if (sdrv->shutdown)
 403                 sdrv->driver.shutdown = spi_drv_shutdown;
 404         return driver_register(&sdrv->driver);
 405 }
 406 EXPORT_SYMBOL_GPL(__spi_register_driver);
 407
 408 /*-------------------------------------------------------------------------*/
 409
 410 /* SPI devices should normally not be created by SPI device drivers; that
 411  * would make them board-specific.  Similarly with SPI controller drivers.
 412  * Device registration normally goes into like arch/.../mach.../board-YYY.c
 413  * with other readonly (flashable) information about mainboard devices.
 414  */
 415
 416 struct boardinfo {
 417         struct list_head        list;
 418         struct spi_board_info   board_info;
 419 };
 420
 421 static LIST_HEAD(board_list);
 422 static LIST_HEAD(spi_controller_list);
 423
 424 /*
 425  * Used to protect add/del opertion for board_info list and
 426  * spi_controller list, and their matching process
 427  * also used to protect object of type struct idr
 428  */
 429 static DEFINE_MUTEX(board_lock);
 430
 431 /**
 432  * spi_alloc_device - Allocate a new SPI device
 433  * @ctlr: Controller to which device is connected
 434  * Context: can sleep
 435  *
 436  * Allows a driver to allocate and initialize a spi_device without
 437  * registering it immediately.  This allows a driver to directly
 438  * fill the spi_device with device parameters before calling
 439  * spi_add_device() on it.
 440  *
 441  * Caller is responsible to call spi_add_device() on the returned
 442  * spi_device structure to add it to the SPI controller.  If the caller
 443  * needs to discard the spi_device without adding it, then it should
 444  * call spi_dev_put() on it.
 445  *
 446  * Return: a pointer to the new device, or NULL.
 447  */
 448 struct spi_device *spi_alloc_device(struct spi_controller *ctlr)
 449 {
 450         struct spi_device       *spi;
 451
 452         if (!spi_controller_get(ctlr))
 453                 return NULL;
 454
 455         spi = kzalloc(sizeof(*spi), GFP_KERNEL);
 456         if (!spi) {
 457                 spi_controller_put(ctlr);
 458                 return NULL;
 459         }
 460
 461         spi->master = spi->controller = ctlr;
 462         spi->dev.parent = &ctlr->dev;
 463         spi->dev.bus = &spi_bus_type;
 464         spi->dev.release = spidev_release;
 465         spi->cs_gpio = -ENOENT;
 466
 467         spin_lock_init(&spi->statistics.lock);
 468
 469         device_initialize(&spi->dev);
 470         return spi;
 471 }
 472 EXPORT_SYMBOL_GPL(spi_alloc_device);
 473
 474 static void spi_dev_set_name(struct spi_device *spi)
 475 {
 476         struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
 477
 478         if (adev) {
 479                 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
 480                 return;
 481         }
 482
 483         dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->controller->dev),
 484                      spi->chip_select);
 485 }
 486
 487 static int spi_dev_check(struct device *dev, void *data)
 488 {
 489         struct spi_device *spi = to_spi_device(dev);
 490         struct spi_device *new_spi = data;
 491
 492         if (spi->controller == new_spi->controller &&
 493             spi->chip_select == new_spi->chip_select)
 494                 return -EBUSY;
 495         return 0;
 496 }
 497
 498 /**
 499  * spi_add_device - Add spi_device allocated with spi_alloc_device
 500  * @spi: spi_device to register
 501  *
 502  * Companion function to spi_alloc_device.  Devices allocated with
 503  * spi_alloc_device can be added onto the spi bus with this function.
 504  *
 505  * Return: 0 on success; negative errno on failure
 506  */
 507 int spi_add_device(struct spi_device *spi)
 508 {
 509         static DEFINE_MUTEX(spi_add_lock);
 510         struct spi_controller *ctlr = spi->controller;
 511         struct device *dev = ctlr->dev.parent;
 512         int status;
 513
 514         /* Chipselects are numbered 0..max; validate. */
 515         if (spi->chip_select >= ctlr->num_chipselect) {
 516                 dev_err(dev, "cs%d >= max %d\n", spi->chip_select,
 517                         ctlr->num_chipselect);
 518                 return -EINVAL;
 519         }
 520
 521         /* Set the bus ID string */
 522         spi_dev_set_name(spi);
 523
 524         /* We need to make sure there's no other device with this
 525          * chipselect **BEFORE** we call setup(), else we'll trash
 526          * its configuration.  Lock against concurrent add() calls.
 527          */
 528         mutex_lock(&spi_add_lock);
 529
 530         status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
 531         if (status) {
 532                 dev_err(dev, "chipselect %d already in use\n",
 533                                 spi->chip_select);
 534                 goto done;
 535         }
 536
 537         if (ctlr->cs_gpios)
 538                 spi->cs_gpio = ctlr->cs_gpios[spi->chip_select];
 539
 540         /* Drivers may modify this initial i/o setup, but will
 541          * normally rely on the device being setup.  Devices
 542          * using SPI_CS_HIGH can't coexist well otherwise...
 543          */
 544         status = spi_setup(spi);
 545         if (status < 0) {
 546                 dev_err(dev, "can't setup %s, status %d\n",
 547                                 dev_name(&spi->dev), status);
 548                 goto done;
 549         }
 550
 551         /* Device may be bound to an active driver when this returns */
 552         status = device_add(&spi->dev);
 553         if (status < 0)
 554                 dev_err(dev, "can't add %s, status %d\n",
 555                                 dev_name(&spi->dev), status);
 556         else
 557                 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
 558
 559 done:
 560         mutex_unlock(&spi_add_lock);
 561         return status;
 562 }
 563 EXPORT_SYMBOL_GPL(spi_add_device);
 564
 565 /**
 566  * spi_new_device - instantiate one new SPI device
 567  * @ctlr: Controller to which device is connected
 568  * @chip: Describes the SPI device
 569  * Context: can sleep
 570  *
 571  * On typical mainboards, this is purely internal; and it's not needed
 572  * after board init creates the hard-wired devices.  Some development
 573  * platforms may not be able to use spi_register_board_info though, and
 574  * this is exported so that for example a USB or parport based adapter
 575  * driver could add devices (which it would learn about out-of-band).
 576  *
 577  * Return: the new device, or NULL.
 578  */
 579 struct spi_device *spi_new_device(struct spi_controller *ctlr,
 580                                   struct spi_board_info *chip)
 581 {
 582         struct spi_device       *proxy;
 583         int                     status;
 584
 585         /* NOTE:  caller did any chip->bus_num checks necessary.
 586          *
 587          * Also, unless we change the return value convention to use
 588          * error-or-pointer (not NULL-or-pointer), troubleshootability
 589          * suggests syslogged diagnostics are best here (ugh).
 590          */
 591
 592         proxy = spi_alloc_device(ctlr);
 593         if (!proxy)
 594                 return NULL;
 595
 596         WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
 597
 598         proxy->chip_select = chip->chip_select;
 599         proxy->max_speed_hz = chip->max_speed_hz;
 600         proxy->mode = chip->mode;
 601         proxy->irq = chip->irq;
 602         strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
 603         proxy->dev.platform_data = (void *) chip->platform_data;
 604         proxy->controller_data = chip->controller_data;
 605         proxy->controller_state = NULL;
 606
 607         if (chip->properties) {
 608                 status = device_add_properties(&proxy->dev, chip->properties);
 609                 if (status) {
 610                         dev_err(&ctlr->dev,
 611                                 "failed to add properties to '%s': %d\n",
 612                                 chip->modalias, status);
 613                         goto err_dev_put;
 614                 }
 615         }
 616
 617         status = spi_add_device(proxy);
 618         if (status < 0)
 619                 goto err_remove_props;
 620
 621         return proxy;
 622
 623 err_remove_props:
 624         if (chip->properties)
 625                 device_remove_properties(&proxy->dev);
 626 err_dev_put:
 627         spi_dev_put(proxy);
 628         return NULL;
 629 }
 630 EXPORT_SYMBOL_GPL(spi_new_device);
 631
 632 /**
 633  * spi_unregister_device - unregister a single SPI device
 634  * @spi: spi_device to unregister
 635  *
 636  * Start making the passed SPI device vanish. Normally this would be handled
 637  * by spi_unregister_controller().
 638  */
 639 void spi_unregister_device(struct spi_device *spi)
 640 {
 641         if (!spi)
 642                 return;
 643
 644         if (spi->dev.of_node) {
 645                 of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
 646                 of_node_put(spi->dev.of_node);
 647         }
 648         if (ACPI_COMPANION(&spi->dev))
 649                 acpi_device_clear_enumerated(ACPI_COMPANION(&spi->dev));
 650         device_unregister(&spi->dev);
 651 }
 652 EXPORT_SYMBOL_GPL(spi_unregister_device);
 653
 654 static void spi_match_controller_to_boardinfo(struct spi_controller *ctlr,
 655                                               struct spi_board_info *bi)
 656 {
 657         struct spi_device *dev;
 658
 659         if (ctlr->bus_num != bi->bus_num)
 660                 return;
 661
 662         dev = spi_new_device(ctlr, bi);
 663         if (!dev)
 664                 dev_err(ctlr->dev.parent, "can't create new device for %s\n",
 665                         bi->modalias);
 666 }
 667
 668 /**
 669  * spi_register_board_info - register SPI devices for a given board
 670  * @info: array of chip descriptors
 671  * @n: how many descriptors are provided
 672  * Context: can sleep
 673  *
 674  * Board-specific early init code calls this (probably during arch_initcall)
 675  * with segments of the SPI device table.  Any device nodes are created later,
 676  * after the relevant parent SPI controller (bus_num) is defined.  We keep
 677  * this table of devices forever, so that reloading a controller driver will
 678  * not make Linux forget about these hard-wired devices.
 679  *
 680  * Other code can also call this, e.g. a particular add-on board might provide
 681  * SPI devices through its expansion connector, so code initializing that board
 682  * would naturally declare its SPI devices.
 683  *
 684  * The board info passed can safely be __initdata ... but be careful of
 685  * any embedded pointers (platform_data, etc), they're copied as-is.
 686  * Device properties are deep-copied though.
 687  *
 688  * Return: zero on success, else a negative error code.
 689  */
 690 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
 691 {
 692         struct boardinfo *bi;
 693         int i;
 694
 695         if (!n)
 696                 return 0;
 697
 698         bi = kcalloc(n, sizeof(*bi), GFP_KERNEL);
 699         if (!bi)
 700                 return -ENOMEM;
 701
 702         for (i = 0; i < n; i++, bi++, info++) {
 703                 struct spi_controller *ctlr;
 704
 705                 memcpy(&bi->board_info, info, sizeof(*info));
 706                 if (info->properties) {
 707                         bi->board_info.properties =
 708                                         property_entries_dup(info->properties);
 709                         if (IS_ERR(bi->board_info.properties))
 710                                 return PTR_ERR(bi->board_info.properties);
 711                 }
 712
 713                 mutex_lock(&board_lock);
 714                 list_add_tail(&bi->list, &board_list);
 715                 list_for_each_entry(ctlr, &spi_controller_list, list)
 716                         spi_match_controller_to_boardinfo(ctlr,
 717                                                           &bi->board_info);
 718                 mutex_unlock(&board_lock);
 719         }
 720
 721         return 0;
 722 }
 723
 724 /*-------------------------------------------------------------------------*/
 725
 726 static void spi_set_cs(struct spi_device *spi, bool enable)
 727 {
 728         if (spi->mode & SPI_CS_HIGH)
 729                 enable = !enable;
 730
 731         if (gpio_is_valid(spi->cs_gpio)) {
 732                 gpio_set_value(spi->cs_gpio, !enable);
 733                 /* Some SPI masters need both GPIO CS & slave_select */
 734                 if ((spi->controller->flags & SPI_MASTER_GPIO_SS) &&
 735                     spi->controller->set_cs)
 736                         spi->controller->set_cs(spi, !enable);
 737         } else if (spi->controller->set_cs) {
 738                 spi->controller->set_cs(spi, !enable);
 739         }
 740 }
 741
 742 #ifdef CONFIG_HAS_DMA
 743 static int spi_map_buf(struct spi_controller *ctlr, struct device *dev,
 744                        struct sg_table *sgt, void *buf, size_t len,
 745                        enum dma_data_direction dir)
 746 {
 747         const bool vmalloced_buf = is_vmalloc_addr(buf);
 748         unsigned int max_seg_size = dma_get_max_seg_size(dev);
 749 #ifdef CONFIG_HIGHMEM
 750         const bool kmap_buf = ((unsigned long)buf >= PKMAP_BASE &&
 751                                 (unsigned long)buf < (PKMAP_BASE +
 752                                         (LAST_PKMAP * PAGE_SIZE)));
 753 #else
 754         const bool kmap_buf = false;
 755 #endif
 756         int desc_len;
 757         int sgs;
 758         struct page *vm_page;
 759         struct scatterlist *sg;
 760         void *sg_buf;
 761         size_t min;
 762         int i, ret;
 763
 764         if (vmalloced_buf || kmap_buf) {
 765                 desc_len = min_t(int, max_seg_size, PAGE_SIZE);
 766                 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
 767         } else if (virt_addr_valid(buf)) {
 768                 desc_len = min_t(int, max_seg_size, ctlr->max_dma_len);
 769                 sgs = DIV_ROUND_UP(len, desc_len);
 770         } else {
 771                 return -EINVAL;
 772         }
 773
 774         ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
 775         if (ret != 0)
 776                 return ret;
 777
 778         sg = &sgt->sgl[0];
 779         for (i = 0; i < sgs; i++) {
 780
 781                 if (vmalloced_buf || kmap_buf) {
 782                         /*
 783                          * Next scatterlist entry size is the minimum between
 784                          * the desc_len and the remaining buffer length that
 785                          * fits in a page.
 786                          */
 787                         min = min_t(size_t, desc_len,
 788                                     min_t(size_t, len,
 789                                           PAGE_SIZE - offset_in_page(buf)));
 790                         if (vmalloced_buf)
 791                                 vm_page = vmalloc_to_page(buf);
 792                         else
 793                                 vm_page = kmap_to_page(buf);
 794                         if (!vm_page) {
 795                                 sg_free_table(sgt);
 796                                 return -ENOMEM;
 797                         }
 798                         sg_set_page(sg, vm_page,
 799                                     min, offset_in_page(buf));
 800                 } else {
 801                         min = min_t(size_t, len, desc_len);
 802                         sg_buf = buf;
 803                         sg_set_buf(sg, sg_buf, min);
 804                 }
 805
 806                 buf += min;
 807                 len -= min;
 808                 sg = sg_next(sg);
 809         }
 810
 811         ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
 812         if (!ret)
 813                 ret = -ENOMEM;
 814         if (ret < 0) {
 815                 sg_free_table(sgt);
 816                 return ret;
 817         }
 818
 819         sgt->nents = ret;
 820
 821         return 0;
 822 }
 823
 824 static void spi_unmap_buf(struct spi_controller *ctlr, struct device *dev,
 825                           struct sg_table *sgt, enum dma_data_direction dir)
 826 {
 827         if (sgt->orig_nents) {
 828                 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
 829                 sg_free_table(sgt);
 830         }
 831 }
 832
 833 static int __spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
 834 {
 835         struct device *tx_dev, *rx_dev;
 836         struct spi_transfer *xfer;
 837         int ret;
 838
 839         if (!ctlr->can_dma)
 840                 return 0;
 841
 842         if (ctlr->dma_tx)
 843                 tx_dev = ctlr->dma_tx->device->dev;
 844         else
 845                 tx_dev = ctlr->dev.parent;
 846
 847         if (ctlr->dma_rx)
 848                 rx_dev = ctlr->dma_rx->device->dev;
 849         else
 850                 rx_dev = ctlr->dev.parent;
 851
 852         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 853                 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
 854                         continue;
 855
 856                 if (xfer->tx_buf != NULL) {
 857                         ret = spi_map_buf(ctlr, tx_dev, &xfer->tx_sg,
 858                                           (void *)xfer->tx_buf, xfer->len,
 859                                           DMA_TO_DEVICE);
 860                         if (ret != 0)
 861                                 return ret;
 862                 }
 863
 864                 if (xfer->rx_buf != NULL) {
 865                         ret = spi_map_buf(ctlr, rx_dev, &xfer->rx_sg,
 866                                           xfer->rx_buf, xfer->len,
 867                                           DMA_FROM_DEVICE);
 868                         if (ret != 0) {
 869                                 spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg,
 870                                               DMA_TO_DEVICE);
 871                                 return ret;
 872                         }
 873                 }
 874         }
 875
 876         ctlr->cur_msg_mapped = true;
 877
 878         return 0;
 879 }
 880
 881 static int __spi_unmap_msg(struct spi_controller *ctlr, struct spi_message *msg)
 882 {
 883         struct spi_transfer *xfer;
 884         struct device *tx_dev, *rx_dev;
 885
 886         if (!ctlr->cur_msg_mapped || !ctlr->can_dma)
 887                 return 0;
 888
 889         if (ctlr->dma_tx)
 890                 tx_dev = ctlr->dma_tx->device->dev;
 891         else
 892                 tx_dev = ctlr->dev.parent;
 893
 894         if (ctlr->dma_rx)
 895                 rx_dev = ctlr->dma_rx->device->dev;
 896         else
 897                 rx_dev = ctlr->dev.parent;
 898
 899         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 900                 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
 901                         continue;
 902
 903                 spi_unmap_buf(ctlr, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
 904                 spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
 905         }
 906
 907         return 0;
 908 }
 909 #else /* !CONFIG_HAS_DMA */
 910 static inline int spi_map_buf(struct spi_controller *ctlr, struct device *dev,
 911                               struct sg_table *sgt, void *buf, size_t len,
 912                               enum dma_data_direction dir)
 913 {
 914         return -EINVAL;
 915 }
 916
 917 static inline void spi_unmap_buf(struct spi_controller *ctlr,
 918                                  struct device *dev, struct sg_table *sgt,
 919                                  enum dma_data_direction dir)
 920 {
 921 }
 922
 923 static inline int __spi_map_msg(struct spi_controller *ctlr,
 924                                 struct spi_message *msg)
 925 {
 926         return 0;
 927 }
 928
 929 static inline int __spi_unmap_msg(struct spi_controller *ctlr,
 930                                   struct spi_message *msg)
 931 {
 932         return 0;
 933 }
 934 #endif /* !CONFIG_HAS_DMA */
 935
 936 static inline int spi_unmap_msg(struct spi_controller *ctlr,
 937                                 struct spi_message *msg)
 938 {
 939         struct spi_transfer *xfer;
 940
 941         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 942                 /*
 943                  * Restore the original value of tx_buf or rx_buf if they are
 944                  * NULL.
 945                  */
 946                 if (xfer->tx_buf == ctlr->dummy_tx)
 947                         xfer->tx_buf = NULL;
 948                 if (xfer->rx_buf == ctlr->dummy_rx)
 949                         xfer->rx_buf = NULL;
 950         }
 951
 952         return __spi_unmap_msg(ctlr, msg);
 953 }
 954
 955 static int spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
 956 {
 957         struct spi_transfer *xfer;
 958         void *tmp;
 959         unsigned int max_tx, max_rx;
 960
 961         if (ctlr->flags & (SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX)) {
 962                 max_tx = 0;
 963                 max_rx = 0;
 964
 965                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 966                         if ((ctlr->flags & SPI_CONTROLLER_MUST_TX) &&
 967                             !xfer->tx_buf)
 968                                 max_tx = max(xfer->len, max_tx);
 969                         if ((ctlr->flags & SPI_CONTROLLER_MUST_RX) &&
 970                             !xfer->rx_buf)
 971                                 max_rx = max(xfer->len, max_rx);
 972                 }
 973
 974                 if (max_tx) {
 975                         tmp = krealloc(ctlr->dummy_tx, max_tx,
 976                                        GFP_KERNEL | GFP_DMA);
 977                         if (!tmp)
 978                                 return -ENOMEM;
 979                         ctlr->dummy_tx = tmp;
 980                         memset(tmp, 0, max_tx);
 981                 }
 982
 983                 if (max_rx) {
 984                         tmp = krealloc(ctlr->dummy_rx, max_rx,
 985                                        GFP_KERNEL | GFP_DMA);
 986                         if (!tmp)
 987                                 return -ENOMEM;
 988                         ctlr->dummy_rx = tmp;
 989                 }
 990
 991                 if (max_tx || max_rx) {
 992                         list_for_each_entry(xfer, &msg->transfers,
 993                                             transfer_list) {
 994                                 if (!xfer->tx_buf)
 995                                         xfer->tx_buf = ctlr->dummy_tx;
 996                                 if (!xfer->rx_buf)
 997                                         xfer->rx_buf = ctlr->dummy_rx;
 998                         }
 999                 }
1000         }
1001
1002         return __spi_map_msg(ctlr, msg);
1003 }
1004
1005 /*
1006  * spi_transfer_one_message - Default implementation of transfer_one_message()
1007  *
1008  * This is a standard implementation of transfer_one_message() for
1009  * drivers which implement a transfer_one() operation.  It provides
1010  * standard handling of delays and chip select management.
1011  */
1012 static int spi_transfer_one_message(struct spi_controller *ctlr,
1013                                     struct spi_message *msg)
1014 {
1015         struct spi_transfer *xfer;
1016         bool keep_cs = false;
1017         int ret = 0;
1018         unsigned long long ms = 1;
1019         struct spi_statistics *statm = &ctlr->statistics;
1020         struct spi_statistics *stats = &msg->spi->statistics;
1021
1022         spi_set_cs(msg->spi, true);
1023
1024         SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
1025         SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
1026
1027         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1028                 trace_spi_transfer_start(msg, xfer);
1029
1030                 spi_statistics_add_transfer_stats(statm, xfer, ctlr);
1031                 spi_statistics_add_transfer_stats(stats, xfer, ctlr);
1032
1033                 if (xfer->tx_buf || xfer->rx_buf) {
1034                         reinit_completion(&ctlr->xfer_completion);
1035
1036                         ret = ctlr->transfer_one(ctlr, msg->spi, xfer);
1037                         if (ret < 0) {
1038                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
1039                                                                errors);
1040                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
1041                                                                errors);
1042                                 dev_err(&msg->spi->dev,
1043                                         "SPI transfer failed: %d\n", ret);
1044                                 goto out;
1045                         }
1046
1047                         if (ret > 0) {
1048                                 ret = 0;
1049                                 ms = 8LL * 1000LL * xfer->len;
1050                                 do_div(ms, xfer->speed_hz);
1051                                 ms += ms + 200; /* some tolerance */
1052
1053                                 if (ms > UINT_MAX)
1054                                         ms = UINT_MAX;
1055
1056                                 ms = wait_for_completion_timeout(&ctlr->xfer_completion,
1057                                                                  msecs_to_jiffies(ms));
1058                         }
1059
1060                         if (ms == 0) {
1061                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
1062                                                                timedout);
1063                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
1064                                                                timedout);
1065                                 dev_err(&msg->spi->dev,
1066                                         "SPI transfer timed out\n");
1067                                 msg->status = -ETIMEDOUT;
1068                         }
1069                 } else {
1070                         if (xfer->len)
1071                                 dev_err(&msg->spi->dev,
1072                                         "Bufferless transfer has length %u\n",
1073                                         xfer->len);
1074                 }
1075
1076                 trace_spi_transfer_stop(msg, xfer);
1077
1078                 if (msg->status != -EINPROGRESS)
1079                         goto out;
1080
1081                 if (xfer->delay_usecs) {
1082                         u16 us = xfer->delay_usecs;
1083
1084                         if (us <= 10)
1085                                 udelay(us);
1086                         else
1087                                 usleep_range(us, us + DIV_ROUND_UP(us, 10));
1088                 }
1089
1090                 if (xfer->cs_change) {
1091                         if (list_is_last(&xfer->transfer_list,
1092                                          &msg->transfers)) {
1093                                 keep_cs = true;
1094                         } else {
1095                                 spi_set_cs(msg->spi, false);
1096                                 udelay(10);
1097                                 spi_set_cs(msg->spi, true);
1098                         }
1099                 }
1100
1101                 msg->actual_length += xfer->len;
1102         }
1103
1104 out:
1105         if (ret != 0 || !keep_cs)
1106                 spi_set_cs(msg->spi, false);
1107
1108         if (msg->status == -EINPROGRESS)
1109                 msg->status = ret;
1110
1111         if (msg->status && ctlr->handle_err)
1112                 ctlr->handle_err(ctlr, msg);
1113
1114         spi_res_release(ctlr, msg);
1115
1116         spi_finalize_current_message(ctlr);
1117
1118         return ret;
1119 }
1120
1121 /**
1122  * spi_finalize_current_transfer - report completion of a transfer
1123  * @ctlr: the controller reporting completion
1124  *
1125  * Called by SPI drivers using the core transfer_one_message()
1126  * implementation to notify it that the current interrupt driven
1127  * transfer has finished and the next one may be scheduled.
1128  */
1129 void spi_finalize_current_transfer(struct spi_controller *ctlr)
1130 {
1131         complete(&ctlr->xfer_completion);
1132 }
1133 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1134
1135 /**
1136  * __spi_pump_messages - function which processes spi message queue
1137  * @ctlr: controller to process queue for
1138  * @in_kthread: true if we are in the context of the message pump thread
1139  *
1140  * This function checks if there is any spi message in the queue that
1141  * needs processing and if so call out to the driver to initialize hardware
1142  * and transfer each message.
1143  *
1144  * Note that it is called both from the kthread itself and also from
1145  * inside spi_sync(); the queue extraction handling at the top of the
1146  * function should deal with this safely.
1147  */
1148 static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread)
1149 {
1150         unsigned long flags;
1151         bool was_busy = false;
1152         int ret;
1153
1154         /* Lock queue */
1155         spin_lock_irqsave(&ctlr->queue_lock, flags);
1156
1157         /* Make sure we are not already running a message */
1158         if (ctlr->cur_msg) {
1159                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1160                 return;
1161         }
1162
1163         /* If another context is idling the device then defer */
1164         if (ctlr->idling) {
1165                 kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1166                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1167                 return;
1168         }
1169
1170         /* Check if the queue is idle */
1171         if (list_empty(&ctlr->queue) || !ctlr->running) {
1172                 if (!ctlr->busy) {
1173                         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1174                         return;
1175                 }
1176
1177                 /* Only do teardown in the thread */
1178                 if (!in_kthread) {
1179                         kthread_queue_work(&ctlr->kworker,
1180                                            &ctlr->pump_messages);
1181                         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1182                         return;
1183                 }
1184
1185                 ctlr->busy = false;
1186                 ctlr->idling = true;
1187                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1188
1189                 kfree(ctlr->dummy_rx);
1190                 ctlr->dummy_rx = NULL;
1191                 kfree(ctlr->dummy_tx);
1192                 ctlr->dummy_tx = NULL;
1193                 if (ctlr->unprepare_transfer_hardware &&
1194                     ctlr->unprepare_transfer_hardware(ctlr))
1195                         dev_err(&ctlr->dev,
1196                                 "failed to unprepare transfer hardware\n");
1197                 if (ctlr->auto_runtime_pm) {
1198                         pm_runtime_mark_last_busy(ctlr->dev.parent);
1199                         pm_runtime_put_autosuspend(ctlr->dev.parent);
1200                 }
1201                 trace_spi_controller_idle(ctlr);
1202
1203                 spin_lock_irqsave(&ctlr->queue_lock, flags);
1204                 ctlr->idling = false;
1205                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1206                 return;
1207         }
1208
1209         /* Extract head of queue */
1210         ctlr->cur_msg =
1211                 list_first_entry(&ctlr->queue, struct spi_message, queue);
1212
1213         list_del_init(&ctlr->cur_msg->queue);
1214         if (ctlr->busy)
1215                 was_busy = true;
1216         else
1217                 ctlr->busy = true;
1218         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1219
1220         mutex_lock(&ctlr->io_mutex);
1221
1222         if (!was_busy && ctlr->auto_runtime_pm) {
1223                 ret = pm_runtime_get_sync(ctlr->dev.parent);
1224                 if (ret < 0) {
1225                         dev_err(&ctlr->dev, "Failed to power device: %d\n",
1226                                 ret);
1227                         mutex_unlock(&ctlr->io_mutex);
1228                         return;
1229                 }
1230         }
1231
1232         if (!was_busy)
1233                 trace_spi_controller_busy(ctlr);
1234
1235         if (!was_busy && ctlr->prepare_transfer_hardware) {
1236                 ret = ctlr->prepare_transfer_hardware(ctlr);
1237                 if (ret) {
1238                         dev_err(&ctlr->dev,
1239                                 "failed to prepare transfer hardware\n");
1240
1241                         if (ctlr->auto_runtime_pm)
1242                                 pm_runtime_put(ctlr->dev.parent);
1243                         mutex_unlock(&ctlr->io_mutex);
1244                         return;
1245                 }
1246         }
1247
1248         trace_spi_message_start(ctlr->cur_msg);
1249
1250         if (ctlr->prepare_message) {
1251                 ret = ctlr->prepare_message(ctlr, ctlr->cur_msg);
1252                 if (ret) {
1253                         dev_err(&ctlr->dev, "failed to prepare message: %d\n",
1254                                 ret);
1255                         ctlr->cur_msg->status = ret;
1256                         spi_finalize_current_message(ctlr);
1257                         goto out;
1258                 }
1259                 ctlr->cur_msg_prepared = true;
1260         }
1261
1262         ret = spi_map_msg(ctlr, ctlr->cur_msg);
1263         if (ret) {
1264                 ctlr->cur_msg->status = ret;
1265                 spi_finalize_current_message(ctlr);
1266                 goto out;
1267         }
1268
1269         ret = ctlr->transfer_one_message(ctlr, ctlr->cur_msg);
1270         if (ret) {
1271                 dev_err(&ctlr->dev,
1272                         "failed to transfer one message from queue\n");
1273                 goto out;
1274         }
1275
1276 out:
1277         mutex_unlock(&ctlr->io_mutex);
1278
1279         /* Prod the scheduler in case transfer_one() was busy waiting */
1280         if (!ret)
1281                 cond_resched();
1282 }
1283
1284 /**
1285  * spi_pump_messages - kthread work function which processes spi message queue
1286  * @work: pointer to kthread work struct contained in the controller struct
1287  */
1288 static void spi_pump_messages(struct kthread_work *work)
1289 {
1290         struct spi_controller *ctlr =
1291                 container_of(work, struct spi_controller, pump_messages);
1292
1293         __spi_pump_messages(ctlr, true);
1294 }
1295
1296 static int spi_init_queue(struct spi_controller *ctlr)
1297 {
1298         struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
1299
1300         ctlr->running = false;
1301         ctlr->busy = false;
1302
1303         kthread_init_worker(&ctlr->kworker);
1304         ctlr->kworker_task = kthread_run(kthread_worker_fn, &ctlr->kworker,
1305                                          "%s", dev_name(&ctlr->dev));
1306         if (IS_ERR(ctlr->kworker_task)) {
1307                 dev_err(&ctlr->dev, "failed to create message pump task\n");
1308                 return PTR_ERR(ctlr->kworker_task);
1309         }
1310         kthread_init_work(&ctlr->pump_messages, spi_pump_messages);
1311
1312         /*
1313          * Controller config will indicate if this controller should run the
1314          * message pump with high (realtime) priority to reduce the transfer
1315          * latency on the bus by minimising the delay between a transfer
1316          * request and the scheduling of the message pump thread. Without this
1317          * setting the message pump thread will remain at default priority.
1318          */
1319         if (ctlr->rt) {
1320                 dev_info(&ctlr->dev,
1321                         "will run message pump with realtime priority\n");
1322                 sched_setscheduler(ctlr->kworker_task, SCHED_FIFO, &param);
1323         }
1324
1325         return 0;
1326 }
1327
1328 /**
1329  * spi_get_next_queued_message() - called by driver to check for queued
1330  * messages
1331  * @ctlr: the controller to check for queued messages
1332  *
1333  * If there are more messages in the queue, the next message is returned from
1334  * this call.
1335  *
1336  * Return: the next message in the queue, else NULL if the queue is empty.
1337  */
1338 struct spi_message *spi_get_next_queued_message(struct spi_controller *ctlr)
1339 {
1340         struct spi_message *next;
1341         unsigned long flags;
1342
1343         /* get a pointer to the next message, if any */
1344         spin_lock_irqsave(&ctlr->queue_lock, flags);
1345         next = list_first_entry_or_null(&ctlr->queue, struct spi_message,
1346                                         queue);
1347         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1348
1349         return next;
1350 }
1351 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1352
1353 /**
1354  * spi_finalize_current_message() - the current message is complete
1355  * @ctlr: the controller to return the message to
1356  *
1357  * Called by the driver to notify the core that the message in the front of the
1358  * queue is complete and can be removed from the queue.
1359  */
1360 void spi_finalize_current_message(struct spi_controller *ctlr)
1361 {
1362         struct spi_message *mesg;
1363         unsigned long flags;
1364         int ret;
1365
1366         spin_lock_irqsave(&ctlr->queue_lock, flags);
1367         mesg = ctlr->cur_msg;
1368         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1369
1370         spi_unmap_msg(ctlr, mesg);
1371
1372         if (ctlr->cur_msg_prepared && ctlr->unprepare_message) {
1373                 ret = ctlr->unprepare_message(ctlr, mesg);
1374                 if (ret) {
1375                         dev_err(&ctlr->dev, "failed to unprepare message: %d\n",
1376                                 ret);
1377                 }
1378         }
1379
1380         spin_lock_irqsave(&ctlr->queue_lock, flags);
1381         ctlr->cur_msg = NULL;
1382         ctlr->cur_msg_prepared = false;
1383         kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1384         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1385
1386         trace_spi_message_done(mesg);
1387
1388         mesg->state = NULL;
1389         if (mesg->complete)
1390                 mesg->complete(mesg->context);
1391 }
1392 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1393
1394 static int spi_start_queue(struct spi_controller *ctlr)
1395 {
1396         unsigned long flags;
1397
1398         spin_lock_irqsave(&ctlr->queue_lock, flags);
1399
1400         if (ctlr->running || ctlr->busy) {
1401                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1402                 return -EBUSY;
1403         }
1404
1405         ctlr->running = true;
1406         ctlr->cur_msg = NULL;
1407         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1408
1409         kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1410
1411         return 0;
1412 }
1413
1414 static int spi_stop_queue(struct spi_controller *ctlr)
1415 {
1416         unsigned long flags;
1417         unsigned limit = 500;
1418         int ret = 0;
1419
1420         spin_lock_irqsave(&ctlr->queue_lock, flags);
1421
1422         /*
1423          * This is a bit lame, but is optimized for the common execution path.
1424          * A wait_queue on the ctlr->busy could be used, but then the common
1425          * execution path (pump_messages) would be required to call wake_up or
1426          * friends on every SPI message. Do this instead.
1427          */
1428         while ((!list_empty(&ctlr->queue) || ctlr->busy) && limit--) {
1429                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1430                 usleep_range(10000, 11000);
1431                 spin_lock_irqsave(&ctlr->queue_lock, flags);
1432         }
1433
1434         if (!list_empty(&ctlr->queue) || ctlr->busy)
1435                 ret = -EBUSY;
1436         else
1437                 ctlr->running = false;
1438
1439         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1440
1441         if (ret) {
1442                 dev_warn(&ctlr->dev, "could not stop message queue\n");
1443                 return ret;
1444         }
1445         return ret;
1446 }
1447
1448 static int spi_destroy_queue(struct spi_controller *ctlr)
1449 {
1450         int ret;
1451
1452         ret = spi_stop_queue(ctlr);
1453
1454         /*
1455          * kthread_flush_worker will block until all work is done.
1456          * If the reason that stop_queue timed out is that the work will never
1457          * finish, then it does no good to call flush/stop thread, so
1458          * return anyway.
1459          */
1460         if (ret) {
1461                 dev_err(&ctlr->dev, "problem destroying queue\n");
1462                 return ret;
1463         }
1464
1465         kthread_flush_worker(&ctlr->kworker);
1466         kthread_stop(ctlr->kworker_task);
1467
1468         return 0;
1469 }
1470
1471 static int __spi_queued_transfer(struct spi_device *spi,
1472                                  struct spi_message *msg,
1473                                  bool need_pump)
1474 {
1475         struct spi_controller *ctlr = spi->controller;
1476         unsigned long flags;
1477
1478         spin_lock_irqsave(&ctlr->queue_lock, flags);
1479
1480         if (!ctlr->running) {
1481                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1482                 return -ESHUTDOWN;
1483         }
1484         msg->actual_length = 0;
1485         msg->status = -EINPROGRESS;
1486
1487         list_add_tail(&msg->queue, &ctlr->queue);
1488         if (!ctlr->busy && need_pump)
1489                 kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1490
1491         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1492         return 0;
1493 }
1494
1495 /**
1496  * spi_queued_transfer - transfer function for queued transfers
1497  * @spi: spi device which is requesting transfer
1498  * @msg: spi message which is to handled is queued to driver queue
1499  *
1500  * Return: zero on success, else a negative error code.
1501  */
1502 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1503 {
1504         return __spi_queued_transfer(spi, msg, true);
1505 }
1506
1507 static int spi_controller_initialize_queue(struct spi_controller *ctlr)
1508 {
1509         int ret;
1510
1511         ctlr->transfer = spi_queued_transfer;
1512         if (!ctlr->transfer_one_message)
1513                 ctlr->transfer_one_message = spi_transfer_one_message;
1514
1515         /* Initialize and start queue */
1516         ret = spi_init_queue(ctlr);
1517         if (ret) {
1518                 dev_err(&ctlr->dev, "problem initializing queue\n");
1519                 goto err_init_queue;
1520         }
1521         ctlr->queued = true;
1522         ret = spi_start_queue(ctlr);
1523         if (ret) {
1524                 dev_err(&ctlr->dev, "problem starting queue\n");
1525                 goto err_start_queue;
1526         }
1527
1528         return 0;
1529
1530 err_start_queue:
1531         spi_destroy_queue(ctlr);
1532 err_init_queue:
1533         return ret;
1534 }
1535
1536 /*-------------------------------------------------------------------------*/
1537
1538 #if defined(CONFIG_OF)
1539 static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
1540                            struct device_node *nc)
1541 {
1542         u32 value;
1543         int rc;
1544
1545         /* Mode (clock phase/polarity/etc.) */
1546         if (of_property_read_bool(nc, "spi-cpha"))
1547                 spi->mode |= SPI_CPHA;
1548         if (of_property_read_bool(nc, "spi-cpol"))
1549                 spi->mode |= SPI_CPOL;
1550         if (of_property_read_bool(nc, "spi-cs-high"))
1551                 spi->mode |= SPI_CS_HIGH;
1552         if (of_property_read_bool(nc, "spi-3wire"))
1553                 spi->mode |= SPI_3WIRE;
1554         if (of_property_read_bool(nc, "spi-lsb-first"))
1555                 spi->mode |= SPI_LSB_FIRST;
1556
1557         /* Device DUAL/QUAD mode */
1558         if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1559                 switch (value) {
1560                 case 1:
1561                         break;
1562                 case 2:
1563                         spi->mode |= SPI_TX_DUAL;
1564                         break;
1565                 case 4:
1566                         spi->mode |= SPI_TX_QUAD;
1567                         break;
1568                 default:
1569                         dev_warn(&ctlr->dev,
1570                                 "spi-tx-bus-width %d not supported\n",
1571                                 value);
1572                         break;
1573                 }
1574         }
1575
1576         if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1577                 switch (value) {
1578                 case 1:
1579                         break;
1580                 case 2:
1581                         spi->mode |= SPI_RX_DUAL;
1582                         break;
1583                 case 4:
1584                         spi->mode |= SPI_RX_QUAD;
1585                         break;
1586                 default:
1587                         dev_warn(&ctlr->dev,
1588                                 "spi-rx-bus-width %d not supported\n",
1589                                 value);
1590                         break;
1591                 }
1592         }
1593
1594         if (spi_controller_is_slave(ctlr)) {
1595                 if (strcmp(nc->name, "slave")) {
1596                         dev_err(&ctlr->dev, "%pOF is not called 'slave'\n",
1597                                 nc);
1598                         return -EINVAL;
1599                 }
1600                 return 0;
1601         }
1602
1603         /* Device address */
1604         rc = of_property_read_u32(nc, "reg", &value);
1605         if (rc) {
1606                 dev_err(&ctlr->dev, "%pOF has no valid 'reg' property (%d)\n",
1607                         nc, rc);
1608                 return rc;
1609         }
1610         spi->chip_select = value;
1611
1612         /* Device speed */
1613         rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1614         if (rc) {
1615                 dev_err(&ctlr->dev,
1616                         "%pOF has no valid 'spi-max-frequency' property (%d)\n", nc, rc);
1617                 return rc;
1618         }
1619         spi->max_speed_hz = value;
1620
1621         return 0;
1622 }
1623
1624 static struct spi_device *
1625 of_register_spi_device(struct spi_controller *ctlr, struct device_node *nc)
1626 {
1627         struct spi_device *spi;
1628         int rc;
1629
1630         /* Alloc an spi_device */
1631         spi = spi_alloc_device(ctlr);
1632         if (!spi) {
1633                 dev_err(&ctlr->dev, "spi_device alloc error for %pOF\n", nc);
1634                 rc = -ENOMEM;
1635                 goto err_out;
1636         }
1637
1638         /* Select device driver */
1639         rc = of_modalias_node(nc, spi->modalias,
1640                                 sizeof(spi->modalias));
1641         if (rc < 0) {
1642                 dev_err(&ctlr->dev, "cannot find modalias for %pOF\n", nc);
1643                 goto err_out;
1644         }
1645
1646         rc = of_spi_parse_dt(ctlr, spi, nc);
1647         if (rc)
1648                 goto err_out;
1649
1650         /* Store a pointer to the node in the device structure */
1651         of_node_get(nc);
1652         spi->dev.of_node = nc;
1653
1654         /* Register the new device */
1655         rc = spi_add_device(spi);
1656         if (rc) {
1657                 dev_err(&ctlr->dev, "spi_device register error %pOF\n", nc);
1658                 goto err_of_node_put;
1659         }
1660
1661         return spi;
1662
1663 err_of_node_put:
1664         of_node_put(nc);
1665 err_out:
1666         spi_dev_put(spi);
1667         return ERR_PTR(rc);
1668 }
1669
1670 /**
1671  * of_register_spi_devices() - Register child devices onto the SPI bus
1672  * @ctlr:       Pointer to spi_controller device
1673  *
1674  * Registers an spi_device for each child node of controller node which
1675  * represents a valid SPI slave.
1676  */
1677 static void of_register_spi_devices(struct spi_controller *ctlr)
1678 {
1679         struct spi_device *spi;
1680         struct device_node *nc;
1681
1682         if (!ctlr->dev.of_node)
1683                 return;
1684
1685         for_each_available_child_of_node(ctlr->dev.of_node, nc) {
1686                 if (of_node_test_and_set_flag(nc, OF_POPULATED))
1687                         continue;
1688                 spi = of_register_spi_device(ctlr, nc);
1689                 if (IS_ERR(spi)) {
1690                         dev_warn(&ctlr->dev,
1691                                  "Failed to create SPI device for %pOF\n", nc);
1692                         of_node_clear_flag(nc, OF_POPULATED);
1693                 }
1694         }
1695 }
1696 #else
1697 static void of_register_spi_devices(struct spi_controller *ctlr) { }
1698 #endif
1699
1700 #ifdef CONFIG_ACPI
1701 static void acpi_spi_parse_apple_properties(struct spi_device *spi)
1702 {
1703         struct acpi_device *dev = ACPI_COMPANION(&spi->dev);
1704         const union acpi_object *obj;
1705
1706         if (!x86_apple_machine)
1707                 return;
1708
1709         if (!acpi_dev_get_property(dev, "spiSclkPeriod", ACPI_TYPE_BUFFER, &obj)
1710             && obj->buffer.length >= 4)
1711                 spi->max_speed_hz  = NSEC_PER_SEC / *(u32 *)obj->buffer.pointer;
1712
1713         if (!acpi_dev_get_property(dev, "spiWordSize", ACPI_TYPE_BUFFER, &obj)
1714             && obj->buffer.length == 8)
1715                 spi->bits_per_word = *(u64 *)obj->buffer.pointer;
1716
1717         if (!acpi_dev_get_property(dev, "spiBitOrder", ACPI_TYPE_BUFFER, &obj)
1718             && obj->buffer.length == 8 && !*(u64 *)obj->buffer.pointer)
1719                 spi->mode |= SPI_LSB_FIRST;
1720
1721         if (!acpi_dev_get_property(dev, "spiSPO", ACPI_TYPE_BUFFER, &obj)
1722             && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
1723                 spi->mode |= SPI_CPOL;
1724
1725         if (!acpi_dev_get_property(dev, "spiSPH", ACPI_TYPE_BUFFER, &obj)
1726             && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
1727                 spi->mode |= SPI_CPHA;
1728 }
1729
1730 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1731 {
1732         struct spi_device *spi = data;
1733         struct spi_controller *ctlr = spi->controller;
1734
1735         if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1736                 struct acpi_resource_spi_serialbus *sb;
1737
1738                 sb = &ares->data.spi_serial_bus;
1739                 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1740                         /*
1741                          * ACPI DeviceSelection numbering is handled by the
1742                          * host controller driver in Windows and can vary
1743                          * from driver to driver. In Linux we always expect
1744                          * 0 .. max - 1 so we need to ask the driver to
1745                          * translate between the two schemes.
1746                          */
1747                         if (ctlr->fw_translate_cs) {
1748                                 int cs = ctlr->fw_translate_cs(ctlr,
1749                                                 sb->device_selection);
1750                                 if (cs < 0)
1751                                         return cs;
1752                                 spi->chip_select = cs;
1753                         } else {
1754                                 spi->chip_select = sb->device_selection;
1755                         }
1756
1757                         spi->max_speed_hz = sb->connection_speed;
1758
1759                         if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1760                                 spi->mode |= SPI_CPHA;
1761                         if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1762                                 spi->mode |= SPI_CPOL;
1763                         if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1764                                 spi->mode |= SPI_CS_HIGH;
1765                 }
1766         } else if (spi->irq < 0) {
1767                 struct resource r;
1768
1769                 if (acpi_dev_resource_interrupt(ares, 0, &r))
1770                         spi->irq = r.start;
1771         }
1772
1773         /* Always tell the ACPI core to skip this resource */
1774         return 1;
1775 }
1776
1777 static acpi_status acpi_register_spi_device(struct spi_controller *ctlr,
1778                                             struct acpi_device *adev)
1779 {
1780         struct list_head resource_list;
1781         struct spi_device *spi;
1782         int ret;
1783
1784         if (acpi_bus_get_status(adev) || !adev->status.present ||
1785             acpi_device_enumerated(adev))
1786                 return AE_OK;
1787
1788         spi = spi_alloc_device(ctlr);
1789         if (!spi) {
1790                 dev_err(&ctlr->dev, "failed to allocate SPI device for %s\n",
1791                         dev_name(&adev->dev));
1792                 return AE_NO_MEMORY;
1793         }
1794
1795         ACPI_COMPANION_SET(&spi->dev, adev);
1796         spi->irq = -1;
1797
1798         INIT_LIST_HEAD(&resource_list);
1799         ret = acpi_dev_get_resources(adev, &resource_list,
1800                                      acpi_spi_add_resource, spi);
1801         acpi_dev_free_resource_list(&resource_list);
1802
1803         acpi_spi_parse_apple_properties(spi);
1804
1805         if (ret < 0 || !spi->max_speed_hz) {
1806                 spi_dev_put(spi);
1807                 return AE_OK;
1808         }
1809
1810         acpi_set_modalias(adev, acpi_device_hid(adev), spi->modalias,
1811                           sizeof(spi->modalias));
1812
1813         if (spi->irq < 0)
1814                 spi->irq = acpi_dev_gpio_irq_get(adev, 0);
1815
1816         acpi_device_set_enumerated(adev);
1817
1818         adev->power.flags.ignore_parent = true;
1819         if (spi_add_device(spi)) {
1820                 adev->power.flags.ignore_parent = false;
1821                 dev_err(&ctlr->dev, "failed to add SPI device %s from ACPI\n",
1822                         dev_name(&adev->dev));
1823                 spi_dev_put(spi);
1824         }
1825
1826         return AE_OK;
1827 }
1828
1829 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1830                                        void *data, void **return_value)
1831 {
1832         struct spi_controller *ctlr = data;
1833         struct acpi_device *adev;
1834
1835         if (acpi_bus_get_device(handle, &adev))
1836                 return AE_OK;
1837
1838         return acpi_register_spi_device(ctlr, adev);
1839 }
1840
1841 static void acpi_register_spi_devices(struct spi_controller *ctlr)
1842 {
1843         acpi_status status;
1844         acpi_handle handle;
1845
1846         handle = ACPI_HANDLE(ctlr->dev.parent);
1847         if (!handle)
1848                 return;
1849
1850         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1851                                      acpi_spi_add_device, NULL, ctlr, NULL);
1852         if (ACPI_FAILURE(status))
1853                 dev_warn(&ctlr->dev, "failed to enumerate SPI slaves\n");
1854 }
1855 #else
1856 static inline void acpi_register_spi_devices(struct spi_controller *ctlr) {}
1857 #endif /* CONFIG_ACPI */
1858
1859 static void spi_controller_release(struct device *dev)
1860 {
1861         struct spi_controller *ctlr;
1862
1863         ctlr = container_of(dev, struct spi_controller, dev);
1864         kfree(ctlr);
1865 }
1866
1867 static struct class spi_master_class = {
1868         .name           = "spi_master",
1869         .owner          = THIS_MODULE,
1870         .dev_release    = spi_controller_release,
1871         .dev_groups     = spi_master_groups,
1872 };
1873
1874 #ifdef CONFIG_SPI_SLAVE
1875 /**
1876  * spi_slave_abort - abort the ongoing transfer request on an SPI slave
1877  *                   controller
1878  * @spi: device used for the current transfer
1879  */
1880 int spi_slave_abort(struct spi_device *spi)
1881 {
1882         struct spi_controller *ctlr = spi->controller;
1883
1884         if (spi_controller_is_slave(ctlr) && ctlr->slave_abort)
1885                 return ctlr->slave_abort(ctlr);
1886
1887         return -ENOTSUPP;
1888 }
1889 EXPORT_SYMBOL_GPL(spi_slave_abort);
1890
1891 static int match_true(struct device *dev, void *data)
1892 {
1893         return 1;
1894 }
1895
1896 static ssize_t spi_slave_show(struct device *dev,
1897                               struct device_attribute *attr, char *buf)
1898 {
1899         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
1900                                                    dev);
1901         struct device *child;
1902
1903         child = device_find_child(&ctlr->dev, NULL, match_true);
1904         return sprintf(buf, "%s\n",
1905                        child ? to_spi_device(child)->modalias : NULL);
1906 }
1907
1908 static ssize_t spi_slave_store(struct device *dev,
1909                                struct device_attribute *attr, const char *buf,
1910                                size_t count)
1911 {
1912         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
1913                                                    dev);
1914         struct spi_device *spi;
1915         struct device *child;
1916         char name[32];
1917         int rc;
1918
1919         rc = sscanf(buf, "%31s", name);
1920         if (rc != 1 || !name[0])
1921                 return -EINVAL;
1922
1923         child = device_find_child(&ctlr->dev, NULL, match_true);
1924         if (child) {
1925                 /* Remove registered slave */
1926                 device_unregister(child);
1927                 put_device(child);
1928         }
1929
1930         if (strcmp(name, "(null)")) {
1931                 /* Register new slave */
1932                 spi = spi_alloc_device(ctlr);
1933                 if (!spi)
1934                         return -ENOMEM;
1935
1936                 strlcpy(spi->modalias, name, sizeof(spi->modalias));
1937
1938                 rc = spi_add_device(spi);
1939                 if (rc) {
1940                         spi_dev_put(spi);
1941                         return rc;
1942                 }
1943         }
1944
1945         return count;
1946 }
1947
1948 static DEVICE_ATTR(slave, 0644, spi_slave_show, spi_slave_store);
1949
1950 static struct attribute *spi_slave_attrs[] = {
1951         &dev_attr_slave.attr,
1952         NULL,
1953 };
1954
1955 static const struct attribute_group spi_slave_group = {
1956         .attrs = spi_slave_attrs,
1957 };
1958
1959 static const struct attribute_group *spi_slave_groups[] = {
1960         &spi_controller_statistics_group,
1961         &spi_slave_group,
1962         NULL,
1963 };
1964
1965 static struct class spi_slave_class = {
1966         .name           = "spi_slave",
1967         .owner          = THIS_MODULE,
1968         .dev_release    = spi_controller_release,
1969         .dev_groups     = spi_slave_groups,
1970 };
1971 #else
1972 extern struct class spi_slave_class;    /* dummy */
1973 #endif
1974
1975 /**
1976  * __spi_alloc_controller - allocate an SPI master or slave controller
1977  * @dev: the controller, possibly using the platform_bus
1978  * @size: how much zeroed driver-private data to allocate; the pointer to this
1979  *      memory is in the driver_data field of the returned device,
1980  *      accessible with spi_controller_get_devdata().
1981  * @slave: flag indicating whether to allocate an SPI master (false) or SPI
1982  *      slave (true) controller
1983  * Context: can sleep
1984  *
1985  * This call is used only by SPI controller drivers, which are the
1986  * only ones directly touching chip registers.  It's how they allocate
1987  * an spi_controller structure, prior to calling spi_register_controller().
1988  *
1989  * This must be called from context that can sleep.
1990  *
1991  * The caller is responsible for assigning the bus number and initializing the
1992  * controller's methods before calling spi_register_controller(); and (after
1993  * errors adding the device) calling spi_controller_put() to prevent a memory
1994  * leak.
1995  *
1996  * Return: the SPI controller structure on success, else NULL.
1997  */
1998 struct spi_controller *__spi_alloc_controller(struct device *dev,
1999                                               unsigned int size, bool slave)
2000 {
2001         struct spi_controller   *ctlr;
2002
2003         if (!dev)
2004                 return NULL;
2005
2006         ctlr = kzalloc(size + sizeof(*ctlr), GFP_KERNEL);
2007         if (!ctlr)
2008                 return NULL;
2009
2010         device_initialize(&ctlr->dev);
2011         ctlr->bus_num = -1;
2012         ctlr->num_chipselect = 1;
2013         ctlr->slave = slave;
2014         if (IS_ENABLED(CONFIG_SPI_SLAVE) && slave)
2015                 ctlr->dev.class = &spi_slave_class;
2016         else
2017                 ctlr->dev.class = &spi_master_class;
2018         ctlr->dev.parent = dev;
2019         pm_suspend_ignore_children(&ctlr->dev, true);
2020         spi_controller_set_devdata(ctlr, &ctlr[1]);
2021
2022         return ctlr;
2023 }
2024 EXPORT_SYMBOL_GPL(__spi_alloc_controller);
2025
2026 #ifdef CONFIG_OF
2027 static int of_spi_register_master(struct spi_controller *ctlr)
2028 {
2029         int nb, i, *cs;
2030         struct device_node *np = ctlr->dev.of_node;
2031
2032         if (!np)
2033                 return 0;
2034
2035         nb = of_gpio_named_count(np, "cs-gpios");
2036         ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2037
2038         /* Return error only for an incorrectly formed cs-gpios property */
2039         if (nb == 0 || nb == -ENOENT)
2040                 return 0;
2041         else if (nb < 0)
2042                 return nb;
2043
2044         cs = devm_kzalloc(&ctlr->dev, sizeof(int) * ctlr->num_chipselect,
2045                           GFP_KERNEL);
2046         ctlr->cs_gpios = cs;
2047
2048         if (!ctlr->cs_gpios)
2049                 return -ENOMEM;
2050
2051         for (i = 0; i < ctlr->num_chipselect; i++)
2052                 cs[i] = -ENOENT;
2053
2054         for (i = 0; i < nb; i++)
2055                 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
2056
2057         return 0;
2058 }
2059 #else
2060 static int of_spi_register_master(struct spi_controller *ctlr)
2061 {
2062         return 0;
2063 }
2064 #endif
2065
2066 /**
2067  * spi_register_controller - register SPI master or slave controller
2068  * @ctlr: initialized master, originally from spi_alloc_master() or
2069  *      spi_alloc_slave()
2070  * Context: can sleep
2071  *
2072  * SPI controllers connect to their drivers using some non-SPI bus,
2073  * such as the platform bus.  The final stage of probe() in that code
2074  * includes calling spi_register_controller() to hook up to this SPI bus glue.
2075  *
2076  * SPI controllers use board specific (often SOC specific) bus numbers,
2077  * and board-specific addressing for SPI devices combines those numbers
2078  * with chip select numbers.  Since SPI does not directly support dynamic
2079  * device identification, boards need configuration tables telling which
2080  * chip is at which address.
2081  *
2082  * This must be called from context that can sleep.  It returns zero on
2083  * success, else a negative error code (dropping the controller's refcount).
2084  * After a successful return, the caller is responsible for calling
2085  * spi_unregister_controller().
2086  *
2087  * Return: zero on success, else a negative error code.
2088  */
2089 int spi_register_controller(struct spi_controller *ctlr)
2090 {
2091         struct device           *dev = ctlr->dev.parent;
2092         struct boardinfo        *bi;
2093         int                     status = -ENODEV;
2094         int                     id, first_dynamic;
2095
2096         if (!dev)
2097                 return -ENODEV;
2098
2099         if (!spi_controller_is_slave(ctlr)) {
2100                 status = of_spi_register_master(ctlr);
2101                 if (status)
2102                         return status;
2103         }
2104
2105         /* even if it's just one always-selected device, there must
2106          * be at least one chipselect
2107          */
2108         if (ctlr->num_chipselect == 0)
2109                 return -EINVAL;
2110         /* allocate dynamic bus number using Linux idr */
2111         if ((ctlr->bus_num < 0) && ctlr->dev.of_node) {
2112                 id = of_alias_get_id(ctlr->dev.of_node, "spi");
2113                 if (id >= 0) {
2114                         ctlr->bus_num = id;
2115                         mutex_lock(&board_lock);
2116                         id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
2117                                        ctlr->bus_num + 1, GFP_KERNEL);
2118                         mutex_unlock(&board_lock);
2119                         if (WARN(id < 0, "couldn't get idr"))
2120                                 return id == -ENOSPC ? -EBUSY : id;
2121                 }
2122         }
2123         if (ctlr->bus_num < 0) {
2124                 first_dynamic = of_alias_get_highest_id("spi");
2125                 if (first_dynamic < 0)
2126                         first_dynamic = 0;
2127                 else
2128                         first_dynamic++;
2129
2130                 mutex_lock(&board_lock);
2131                 id = idr_alloc(&spi_master_idr, ctlr, first_dynamic,
2132                                0, GFP_KERNEL);
2133                 mutex_unlock(&board_lock);
2134                 if (WARN(id < 0, "couldn't get idr"))
2135                         return id;
2136                 ctlr->bus_num = id;
2137         }
2138         INIT_LIST_HEAD(&ctlr->queue);
2139         spin_lock_init(&ctlr->queue_lock);
2140         spin_lock_init(&ctlr->bus_lock_spinlock);
2141         mutex_init(&ctlr->bus_lock_mutex);
2142         mutex_init(&ctlr->io_mutex);
2143         ctlr->bus_lock_flag = 0;
2144         init_completion(&ctlr->xfer_completion);
2145         if (!ctlr->max_dma_len)
2146                 ctlr->max_dma_len = INT_MAX;
2147
2148         /* register the device, then userspace will see it.
2149          * registration fails if the bus ID is in use.
2150          */
2151         dev_set_name(&ctlr->dev, "spi%u", ctlr->bus_num);
2152         status = device_add(&ctlr->dev);
2153         if (status < 0) {
2154                 /* free bus id */
2155                 mutex_lock(&board_lock);
2156                 idr_remove(&spi_master_idr, ctlr->bus_num);
2157                 mutex_unlock(&board_lock);
2158                 goto done;
2159         }
2160         dev_dbg(dev, "registered %s %s\n",
2161                         spi_controller_is_slave(ctlr) ? "slave" : "master",
2162                         dev_name(&ctlr->dev));
2163
2164         /* If we're using a queued driver, start the queue */
2165         if (ctlr->transfer)
2166                 dev_info(dev, "controller is unqueued, this is deprecated\n");
2167         else {
2168                 status = spi_controller_initialize_queue(ctlr);
2169                 if (status) {
2170                         device_del(&ctlr->dev);
2171                         /* free bus id */
2172                         mutex_lock(&board_lock);
2173                         idr_remove(&spi_master_idr, ctlr->bus_num);
2174                         mutex_unlock(&board_lock);
2175                         goto done;
2176                 }
2177         }
2178         /* add statistics */
2179         spin_lock_init(&ctlr->statistics.lock);
2180
2181         mutex_lock(&board_lock);
2182         list_add_tail(&ctlr->list, &spi_controller_list);
2183         list_for_each_entry(bi, &board_list, list)
2184                 spi_match_controller_to_boardinfo(ctlr, &bi->board_info);
2185         mutex_unlock(&board_lock);
2186
2187         /* Register devices from the device tree and ACPI */
2188         of_register_spi_devices(ctlr);
2189         acpi_register_spi_devices(ctlr);
2190 done:
2191         return status;
2192 }
2193 EXPORT_SYMBOL_GPL(spi_register_controller);
2194
2195 static void devm_spi_unregister(struct device *dev, void *res)
2196 {
2197         spi_unregister_controller(*(struct spi_controller **)res);
2198 }
2199
2200 /**
2201  * devm_spi_register_controller - register managed SPI master or slave
2202  *      controller
2203  * @dev:    device managing SPI controller
2204  * @ctlr: initialized controller, originally from spi_alloc_master() or
2205  *      spi_alloc_slave()
2206  * Context: can sleep
2207  *
2208  * Register a SPI device as with spi_register_controller() which will
2209  * automatically be unregistered and freed.
2210  *
2211  * Return: zero on success, else a negative error code.
2212  */
2213 int devm_spi_register_controller(struct device *dev,
2214                                  struct spi_controller *ctlr)
2215 {
2216         struct spi_controller **ptr;
2217         int ret;
2218
2219         ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
2220         if (!ptr)
2221                 return -ENOMEM;
2222
2223         ret = spi_register_controller(ctlr);
2224         if (!ret) {
2225                 *ptr = ctlr;
2226                 devres_add(dev, ptr);
2227         } else {
2228                 devres_free(ptr);
2229         }
2230
2231         return ret;
2232 }
2233 EXPORT_SYMBOL_GPL(devm_spi_register_controller);
2234
2235 static int __unregister(struct device *dev, void *null)
2236 {
2237         spi_unregister_device(to_spi_device(dev));
2238         return 0;
2239 }
2240
2241 /**
2242  * spi_unregister_controller - unregister SPI master or slave controller
2243  * @ctlr: the controller being unregistered
2244  * Context: can sleep
2245  *
2246  * This call is used only by SPI controller drivers, which are the
2247  * only ones directly touching chip registers.
2248  *
2249  * This must be called from context that can sleep.
2250  *
2251  * Note that this function also drops a reference to the controller.
2252  */
2253 void spi_unregister_controller(struct spi_controller *ctlr)
2254 {
2255         struct spi_controller *found;
2256         int id = ctlr->bus_num;
2257         int dummy;
2258
2259         /* First make sure that this controller was ever added */
2260         mutex_lock(&board_lock);
2261         found = idr_find(&spi_master_idr, id);
2262         mutex_unlock(&board_lock);
2263         if (ctlr->queued) {
2264                 if (spi_destroy_queue(ctlr))
2265                         dev_err(&ctlr->dev, "queue remove failed\n");
2266         }
2267         mutex_lock(&board_lock);
2268         list_del(&ctlr->list);
2269         mutex_unlock(&board_lock);
2270
2271         dummy = device_for_each_child(&ctlr->dev, NULL, __unregister);
2272         device_unregister(&ctlr->dev);
2273         /* free bus id */
2274         mutex_lock(&board_lock);
2275         if (found == ctlr)
2276                 idr_remove(&spi_master_idr, id);
2277         mutex_unlock(&board_lock);
2278 }
2279 EXPORT_SYMBOL_GPL(spi_unregister_controller);
2280
2281 int spi_controller_suspend(struct spi_controller *ctlr)
2282 {
2283         int ret;
2284
2285         /* Basically no-ops for non-queued controllers */
2286         if (!ctlr->queued)
2287                 return 0;
2288
2289         ret = spi_stop_queue(ctlr);
2290         if (ret)
2291                 dev_err(&ctlr->dev, "queue stop failed\n");
2292
2293         return ret;
2294 }
2295 EXPORT_SYMBOL_GPL(spi_controller_suspend);
2296
2297 int spi_controller_resume(struct spi_controller *ctlr)
2298 {
2299         int ret;
2300
2301         if (!ctlr->queued)
2302                 return 0;
2303
2304         ret = spi_start_queue(ctlr);
2305         if (ret)
2306                 dev_err(&ctlr->dev, "queue restart failed\n");
2307
2308         return ret;
2309 }
2310 EXPORT_SYMBOL_GPL(spi_controller_resume);
2311
2312 static int __spi_controller_match(struct device *dev, const void *data)
2313 {
2314         struct spi_controller *ctlr;
2315         const u16 *bus_num = data;
2316
2317         ctlr = container_of(dev, struct spi_controller, dev);
2318         return ctlr->bus_num == *bus_num;
2319 }
2320
2321 /**
2322  * spi_busnum_to_master - look up master associated with bus_num
2323  * @bus_num: the master's bus number
2324  * Context: can sleep
2325  *
2326  * This call may be used with devices that are registered after
2327  * arch init time.  It returns a refcounted pointer to the relevant
2328  * spi_controller (which the caller must release), or NULL if there is
2329  * no such master registered.
2330  *
2331  * Return: the SPI master structure on success, else NULL.
2332  */
2333 struct spi_controller *spi_busnum_to_master(u16 bus_num)
2334 {
2335         struct device           *dev;
2336         struct spi_controller   *ctlr = NULL;
2337
2338         dev = class_find_device(&spi_master_class, NULL, &bus_num,
2339                                 __spi_controller_match);
2340         if (dev)
2341                 ctlr = container_of(dev, struct spi_controller, dev);
2342         /* reference got in class_find_device */
2343         return ctlr;
2344 }
2345 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
2346
2347 /*-------------------------------------------------------------------------*/
2348
2349 /* Core methods for SPI resource management */
2350
2351 /**
2352  * spi_res_alloc - allocate a spi resource that is life-cycle managed
2353  *                 during the processing of a spi_message while using
2354  *                 spi_transfer_one
2355  * @spi:     the spi device for which we allocate memory
2356  * @release: the release code to execute for this resource
2357  * @size:    size to alloc and return
2358  * @gfp:     GFP allocation flags
2359  *
2360  * Return: the pointer to the allocated data
2361  *
2362  * This may get enhanced in the future to allocate from a memory pool
2363  * of the @spi_device or @spi_controller to avoid repeated allocations.
2364  */
2365 void *spi_res_alloc(struct spi_device *spi,
2366                     spi_res_release_t release,
2367                     size_t size, gfp_t gfp)
2368 {
2369         struct spi_res *sres;
2370
2371         sres = kzalloc(sizeof(*sres) + size, gfp);
2372         if (!sres)
2373                 return NULL;
2374
2375         INIT_LIST_HEAD(&sres->entry);
2376         sres->release = release;
2377
2378         return sres->data;
2379 }
2380 EXPORT_SYMBOL_GPL(spi_res_alloc);
2381
2382 /**
2383  * spi_res_free - free an spi resource
2384  * @res: pointer to the custom data of a resource
2385  *
2386  */
2387 void spi_res_free(void *res)
2388 {
2389         struct spi_res *sres = container_of(res, struct spi_res, data);
2390
2391         if (!res)
2392                 return;
2393
2394         WARN_ON(!list_empty(&sres->entry));
2395         kfree(sres);
2396 }
2397 EXPORT_SYMBOL_GPL(spi_res_free);
2398
2399 /**
2400  * spi_res_add - add a spi_res to the spi_message
2401  * @message: the spi message
2402  * @res:     the spi_resource
2403  */
2404 void spi_res_add(struct spi_message *message, void *res)
2405 {
2406         struct spi_res *sres = container_of(res, struct spi_res, data);
2407
2408         WARN_ON(!list_empty(&sres->entry));
2409         list_add_tail(&sres->entry, &message->resources);
2410 }
2411 EXPORT_SYMBOL_GPL(spi_res_add);
2412
2413 /**
2414  * spi_res_release - release all spi resources for this message
2415  * @ctlr:  the @spi_controller
2416  * @message: the @spi_message
2417  */
2418 void spi_res_release(struct spi_controller *ctlr, struct spi_message *message)
2419 {
2420         struct spi_res *res;
2421
2422         while (!list_empty(&message->resources)) {
2423                 res = list_last_entry(&message->resources,
2424                                       struct spi_res, entry);
2425
2426                 if (res->release)
2427                         res->release(ctlr, message, res->data);
2428
2429                 list_del(&res->entry);
2430
2431                 kfree(res);
2432         }
2433 }
2434 EXPORT_SYMBOL_GPL(spi_res_release);
2435
2436 /*-------------------------------------------------------------------------*/
2437
2438 /* Core methods for spi_message alterations */
2439
2440 static void __spi_replace_transfers_release(struct spi_controller *ctlr,
2441                                             struct spi_message *msg,
2442                                             void *res)
2443 {
2444         struct spi_replaced_transfers *rxfer = res;
2445         size_t i;
2446
2447         /* call extra callback if requested */
2448         if (rxfer->release)
2449                 rxfer->release(ctlr, msg, res);
2450
2451         /* insert replaced transfers back into the message */
2452         list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
2453
2454         /* remove the formerly inserted entries */
2455         for (i = 0; i < rxfer->inserted; i++)
2456                 list_del(&rxfer->inserted_transfers[i].transfer_list);
2457 }
2458
2459 /**
2460  * spi_replace_transfers - replace transfers with several transfers
2461  *                         and register change with spi_message.resources
2462  * @msg:           the spi_message we work upon
2463  * @xfer_first:    the first spi_transfer we want to replace
2464  * @remove:        number of transfers to remove
2465  * @insert:        the number of transfers we want to insert instead
2466  * @release:       extra release code necessary in some circumstances
2467  * @extradatasize: extra data to allocate (with alignment guarantees
2468  *                 of struct @spi_transfer)
2469  * @gfp:           gfp flags
2470  *
2471  * Returns: pointer to @spi_replaced_transfers,
2472  *          PTR_ERR(...) in case of errors.
2473  */
2474 struct spi_replaced_transfers *spi_replace_transfers(
2475         struct spi_message *msg,
2476         struct spi_transfer *xfer_first,
2477         size_t remove,
2478         size_t insert,
2479         spi_replaced_release_t release,
2480         size_t extradatasize,
2481         gfp_t gfp)
2482 {
2483         struct spi_replaced_transfers *rxfer;
2484         struct spi_transfer *xfer;
2485         size_t i;
2486
2487         /* allocate the structure using spi_res */
2488         rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
2489                               insert * sizeof(struct spi_transfer)
2490                               + sizeof(struct spi_replaced_transfers)
2491                               + extradatasize,
2492                               gfp);
2493         if (!rxfer)
2494                 return ERR_PTR(-ENOMEM);
2495
2496         /* the release code to invoke before running the generic release */
2497         rxfer->release = release;
2498
2499         /* assign extradata */
2500         if (extradatasize)
2501                 rxfer->extradata =
2502                         &rxfer->inserted_transfers[insert];
2503
2504         /* init the replaced_transfers list */
2505         INIT_LIST_HEAD(&rxfer->replaced_transfers);
2506
2507         /* assign the list_entry after which we should reinsert
2508          * the @replaced_transfers - it may be spi_message.messages!
2509          */
2510         rxfer->replaced_after = xfer_first->transfer_list.prev;
2511
2512         /* remove the requested number of transfers */
2513         for (i = 0; i < remove; i++) {
2514                 /* if the entry after replaced_after it is msg->transfers
2515                  * then we have been requested to remove more transfers
2516                  * than are in the list
2517                  */
2518                 if (rxfer->replaced_after->next == &msg->transfers) {
2519                         dev_err(&msg->spi->dev,
2520                                 "requested to remove more spi_transfers than are available\n");
2521                         /* insert replaced transfers back into the message */
2522                         list_splice(&rxfer->replaced_transfers,
2523                                     rxfer->replaced_after);
2524
2525                         /* free the spi_replace_transfer structure */
2526                         spi_res_free(rxfer);
2527
2528                         /* and return with an error */
2529                         return ERR_PTR(-EINVAL);
2530                 }
2531
2532                 /* remove the entry after replaced_after from list of
2533                  * transfers and add it to list of replaced_transfers
2534                  */
2535                 list_move_tail(rxfer->replaced_after->next,
2536                                &rxfer->replaced_transfers);
2537         }
2538
2539         /* create copy of the given xfer with identical settings
2540          * based on the first transfer to get removed
2541          */
2542         for (i = 0; i < insert; i++) {
2543                 /* we need to run in reverse order */
2544                 xfer = &rxfer->inserted_transfers[insert - 1 - i];
2545
2546                 /* copy all spi_transfer data */
2547                 memcpy(xfer, xfer_first, sizeof(*xfer));
2548
2549                 /* add to list */
2550                 list_add(&xfer->transfer_list, rxfer->replaced_after);
2551
2552                 /* clear cs_change and delay_usecs for all but the last */
2553                 if (i) {
2554                         xfer->cs_change = false;
2555                         xfer->delay_usecs = 0;
2556                 }
2557         }
2558
2559         /* set up inserted */
2560         rxfer->inserted = insert;
2561
2562         /* and register it with spi_res/spi_message */
2563         spi_res_add(msg, rxfer);
2564
2565         return rxfer;
2566 }
2567 EXPORT_SYMBOL_GPL(spi_replace_transfers);
2568
2569 static int __spi_split_transfer_maxsize(struct spi_controller *ctlr,
2570                                         struct spi_message *msg,
2571                                         struct spi_transfer **xferp,
2572                                         size_t maxsize,
2573                                         gfp_t gfp)
2574 {
2575         struct spi_transfer *xfer = *xferp, *xfers;
2576         struct spi_replaced_transfers *srt;
2577         size_t offset;
2578         size_t count, i;
2579
2580         /* warn once about this fact that we are splitting a transfer */
2581         dev_warn_once(&msg->spi->dev,
2582                       "spi_transfer of length %i exceed max length of %zu - needed to split transfers\n",
2583                       xfer->len, maxsize);
2584
2585         /* calculate how many we have to replace */
2586         count = DIV_ROUND_UP(xfer->len, maxsize);
2587
2588         /* create replacement */
2589         srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
2590         if (IS_ERR(srt))
2591                 return PTR_ERR(srt);
2592         xfers = srt->inserted_transfers;
2593
2594         /* now handle each of those newly inserted spi_transfers
2595          * note that the replacements spi_transfers all are preset
2596          * to the same values as *xferp, so tx_buf, rx_buf and len
2597          * are all identical (as well as most others)
2598          * so we just have to fix up len and the pointers.
2599          *
2600          * this also includes support for the depreciated
2601          * spi_message.is_dma_mapped interface
2602          */
2603
2604         /* the first transfer just needs the length modified, so we
2605          * run it outside the loop
2606          */
2607         xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
2608
2609         /* all the others need rx_buf/tx_buf also set */
2610         for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
2611                 /* update rx_buf, tx_buf and dma */
2612                 if (xfers[i].rx_buf)
2613                         xfers[i].rx_buf += offset;
2614                 if (xfers[i].rx_dma)
2615                         xfers[i].rx_dma += offset;
2616                 if (xfers[i].tx_buf)
2617                         xfers[i].tx_buf += offset;
2618                 if (xfers[i].tx_dma)
2619                         xfers[i].tx_dma += offset;
2620
2621                 /* update length */
2622                 xfers[i].len = min(maxsize, xfers[i].len - offset);
2623         }
2624
2625         /* we set up xferp to the last entry we have inserted,
2626          * so that we skip those already split transfers
2627          */
2628         *xferp = &xfers[count - 1];
2629
2630         /* increment statistics counters */
2631         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
2632                                        transfers_split_maxsize);
2633         SPI_STATISTICS_INCREMENT_FIELD(&msg->spi->statistics,
2634                                        transfers_split_maxsize);
2635
2636         return 0;
2637 }
2638
2639 /**
2640  * spi_split_tranfers_maxsize - split spi transfers into multiple transfers
2641  *                              when an individual transfer exceeds a
2642  *                              certain size
2643  * @ctlr:    the @spi_controller for this transfer
2644  * @msg:   the @spi_message to transform
2645  * @maxsize:  the maximum when to apply this
2646  * @gfp: GFP allocation flags
2647  *
2648  * Return: status of transformation
2649  */
2650 int spi_split_transfers_maxsize(struct spi_controller *ctlr,
2651                                 struct spi_message *msg,
2652                                 size_t maxsize,
2653                                 gfp_t gfp)
2654 {
2655         struct spi_transfer *xfer;
2656         int ret;
2657
2658         /* iterate over the transfer_list,
2659          * but note that xfer is advanced to the last transfer inserted
2660          * to avoid checking sizes again unnecessarily (also xfer does
2661          * potentiall belong to a different list by the time the
2662          * replacement has happened
2663          */
2664         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
2665                 if (xfer->len > maxsize) {
2666                         ret = __spi_split_transfer_maxsize(ctlr, msg, &xfer,
2667                                                            maxsize, gfp);
2668                         if (ret)
2669                                 return ret;
2670                 }
2671         }
2672
2673         return 0;
2674 }
2675 EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
2676
2677 /*-------------------------------------------------------------------------*/
2678
2679 /* Core methods for SPI controller protocol drivers.  Some of the
2680  * other core methods are currently defined as inline functions.
2681  */
2682
2683 static int __spi_validate_bits_per_word(struct spi_controller *ctlr,
2684                                         u8 bits_per_word)
2685 {
2686         if (ctlr->bits_per_word_mask) {
2687                 /* Only 32 bits fit in the mask */
2688                 if (bits_per_word > 32)
2689                         return -EINVAL;
2690                 if (!(ctlr->bits_per_word_mask & SPI_BPW_MASK(bits_per_word)))
2691                         return -EINVAL;
2692         }
2693
2694         return 0;
2695 }
2696
2697 /**
2698  * spi_setup - setup SPI mode and clock rate
2699  * @spi: the device whose settings are being modified
2700  * Context: can sleep, and no requests are queued to the device
2701  *
2702  * SPI protocol drivers may need to update the transfer mode if the
2703  * device doesn't work with its default.  They may likewise need
2704  * to update clock rates or word sizes from initial values.  This function
2705  * changes those settings, and must be called from a context that can sleep.
2706  * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
2707  * effect the next time the device is selected and data is transferred to
2708  * or from it.  When this function returns, the spi device is deselected.
2709  *
2710  * Note that this call will fail if the protocol driver specifies an option
2711  * that the underlying controller or its driver does not support.  For
2712  * example, not all hardware supports wire transfers using nine bit words,
2713  * LSB-first wire encoding, or active-high chipselects.
2714  *
2715  * Return: zero on success, else a negative error code.
2716  */
2717 int spi_setup(struct spi_device *spi)
2718 {
2719         unsigned        bad_bits, ugly_bits;
2720         int             status;
2721
2722         /* check mode to prevent that DUAL and QUAD set at the same time
2723          */
2724         if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
2725                 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
2726                 dev_err(&spi->dev,
2727                 "setup: can not select dual and quad at the same time\n");
2728                 return -EINVAL;
2729         }
2730         /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
2731          */
2732         if ((spi->mode & SPI_3WIRE) && (spi->mode &
2733                 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
2734                 return -EINVAL;
2735         /* help drivers fail *cleanly* when they need options
2736          * that aren't supported with their current controller
2737          */
2738         bad_bits = spi->mode & ~spi->controller->mode_bits;
2739         ugly_bits = bad_bits &
2740                     (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD);
2741         if (ugly_bits) {
2742                 dev_warn(&spi->dev,
2743                          "setup: ignoring unsupported mode bits %x\n",
2744                          ugly_bits);
2745                 spi->mode &= ~ugly_bits;
2746                 bad_bits &= ~ugly_bits;
2747         }
2748         if (bad_bits) {
2749                 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
2750                         bad_bits);
2751                 return -EINVAL;
2752         }
2753
2754         if (!spi->bits_per_word)
2755                 spi->bits_per_word = 8;
2756
2757         status = __spi_validate_bits_per_word(spi->controller,
2758                                               spi->bits_per_word);
2759         if (status)
2760                 return status;
2761
2762         if (!spi->max_speed_hz)
2763                 spi->max_speed_hz = spi->controller->max_speed_hz;
2764
2765         if (spi->controller->setup)
2766                 status = spi->controller->setup(spi);
2767
2768         spi_set_cs(spi, false);
2769
2770         dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
2771                         (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
2772                         (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
2773                         (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
2774                         (spi->mode & SPI_3WIRE) ? "3wire, " : "",
2775                         (spi->mode & SPI_LOOP) ? "loopback, " : "",
2776                         spi->bits_per_word, spi->max_speed_hz,
2777                         status);
2778
2779         return status;
2780 }
2781 EXPORT_SYMBOL_GPL(spi_setup);
2782
2783 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
2784 {
2785         struct spi_controller *ctlr = spi->controller;
2786         struct spi_transfer *xfer;
2787         int w_size;
2788
2789         if (list_empty(&message->transfers))
2790                 return -EINVAL;
2791
2792         /* Half-duplex links include original MicroWire, and ones with
2793          * only one data pin like SPI_3WIRE (switches direction) or where
2794          * either MOSI or MISO is missing.  They can also be caused by
2795          * software limitations.
2796          */
2797         if ((ctlr->flags & SPI_CONTROLLER_HALF_DUPLEX) ||
2798             (spi->mode & SPI_3WIRE)) {
2799                 unsigned flags = ctlr->flags;
2800
2801                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
2802                         if (xfer->rx_buf && xfer->tx_buf)
2803                                 return -EINVAL;
2804                         if ((flags & SPI_CONTROLLER_NO_TX) && xfer->tx_buf)
2805                                 return -EINVAL;
2806                         if ((flags & SPI_CONTROLLER_NO_RX) && xfer->rx_buf)
2807                                 return -EINVAL;
2808                 }
2809         }
2810
2811         /**
2812          * Set transfer bits_per_word and max speed as spi device default if
2813          * it is not set for this transfer.
2814          * Set transfer tx_nbits and rx_nbits as single transfer default
2815          * (SPI_NBITS_SINGLE) if it is not set for this transfer.
2816          */
2817         message->frame_length = 0;
2818         list_for_each_entry(xfer, &message->transfers, transfer_list) {
2819                 message->frame_length += xfer->len;
2820                 if (!xfer->bits_per_word)
2821                         xfer->bits_per_word = spi->bits_per_word;
2822
2823                 if (!xfer->speed_hz)
2824                         xfer->speed_hz = spi->max_speed_hz;
2825                 if (!xfer->speed_hz)
2826                         xfer->speed_hz = ctlr->max_speed_hz;
2827
2828                 if (ctlr->max_speed_hz && xfer->speed_hz > ctlr->max_speed_hz)
2829                         xfer->speed_hz = ctlr->max_speed_hz;
2830
2831                 if (__spi_validate_bits_per_word(ctlr, xfer->bits_per_word))
2832                         return -EINVAL;
2833
2834                 /*
2835                  * SPI transfer length should be multiple of SPI word size
2836                  * where SPI word size should be power-of-two multiple
2837                  */
2838                 if (xfer->bits_per_word <= 8)
2839                         w_size = 1;
2840                 else if (xfer->bits_per_word <= 16)
2841                         w_size = 2;
2842                 else
2843                         w_size = 4;
2844
2845                 /* No partial transfers accepted */
2846                 if (xfer->len % w_size)
2847                         return -EINVAL;
2848
2849                 if (xfer->speed_hz && ctlr->min_speed_hz &&
2850                     xfer->speed_hz < ctlr->min_speed_hz)
2851                         return -EINVAL;
2852
2853                 if (xfer->tx_buf && !xfer->tx_nbits)
2854                         xfer->tx_nbits = SPI_NBITS_SINGLE;
2855                 if (xfer->rx_buf && !xfer->rx_nbits)
2856                         xfer->rx_nbits = SPI_NBITS_SINGLE;
2857                 /* check transfer tx/rx_nbits:
2858                  * 1. check the value matches one of single, dual and quad
2859                  * 2. check tx/rx_nbits match the mode in spi_device
2860                  */
2861                 if (xfer->tx_buf) {
2862                         if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
2863                                 xfer->tx_nbits != SPI_NBITS_DUAL &&
2864                                 xfer->tx_nbits != SPI_NBITS_QUAD)
2865                                 return -EINVAL;
2866                         if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
2867                                 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2868                                 return -EINVAL;
2869                         if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
2870                                 !(spi->mode & SPI_TX_QUAD))
2871                                 return -EINVAL;
2872                 }
2873                 /* check transfer rx_nbits */
2874                 if (xfer->rx_buf) {
2875                         if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
2876                                 xfer->rx_nbits != SPI_NBITS_DUAL &&
2877                                 xfer->rx_nbits != SPI_NBITS_QUAD)
2878                                 return -EINVAL;
2879                         if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
2880                                 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2881                                 return -EINVAL;
2882                         if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
2883                                 !(spi->mode & SPI_RX_QUAD))
2884                                 return -EINVAL;
2885                 }
2886         }
2887
2888         message->status = -EINPROGRESS;
2889
2890         return 0;
2891 }
2892
2893 static int __spi_async(struct spi_device *spi, struct spi_message *message)
2894 {
2895         struct spi_controller *ctlr = spi->controller;
2896
2897         message->spi = spi;
2898
2899         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_async);
2900         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
2901
2902         trace_spi_message_submit(message);
2903
2904         return ctlr->transfer(spi, message);
2905 }
2906
2907 /**
2908  * spi_async - asynchronous SPI transfer
2909  * @spi: device with which data will be exchanged
2910  * @message: describes the data transfers, including completion callback
2911  * Context: any (irqs may be blocked, etc)
2912  *
2913  * This call may be used in_irq and other contexts which can't sleep,
2914  * as well as from task contexts which can sleep.
2915  *
2916  * The completion callback is invoked in a context which can't sleep.
2917  * Before that invocation, the value of message->status is undefined.
2918  * When the callback is issued, message->status holds either zero (to
2919  * indicate complete success) or a negative error code.  After that
2920  * callback returns, the driver which issued the transfer request may
2921  * deallocate the associated memory; it's no longer in use by any SPI
2922  * core or controller driver code.
2923  *
2924  * Note that although all messages to a spi_device are handled in
2925  * FIFO order, messages may go to different devices in other orders.
2926  * Some device might be higher priority, or have various "hard" access
2927  * time requirements, for example.
2928  *
2929  * On detection of any fault during the transfer, processing of
2930  * the entire message is aborted, and the device is deselected.
2931  * Until returning from the associated message completion callback,
2932  * no other spi_message queued to that device will be processed.
2933  * (This rule applies equally to all the synchronous transfer calls,
2934  * which are wrappers around this core asynchronous primitive.)
2935  *
2936  * Return: zero on success, else a negative error code.
2937  */
2938 int spi_async(struct spi_device *spi, struct spi_message *message)
2939 {
2940         struct spi_controller *ctlr = spi->controller;
2941         int ret;
2942         unsigned long flags;
2943
2944         ret = __spi_validate(spi, message);
2945         if (ret != 0)
2946                 return ret;
2947
2948         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
2949
2950         if (ctlr->bus_lock_flag)
2951                 ret = -EBUSY;
2952         else
2953                 ret = __spi_async(spi, message);
2954
2955         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
2956
2957         return ret;
2958 }
2959 EXPORT_SYMBOL_GPL(spi_async);
2960
2961 /**
2962  * spi_async_locked - version of spi_async with exclusive bus usage
2963  * @spi: device with which data will be exchanged
2964  * @message: describes the data transfers, including completion callback
2965  * Context: any (irqs may be blocked, etc)
2966  *
2967  * This call may be used in_irq and other contexts which can't sleep,
2968  * as well as from task contexts which can sleep.
2969  *
2970  * The completion callback is invoked in a context which can't sleep.
2971  * Before that invocation, the value of message->status is undefined.
2972  * When the callback is issued, message->status holds either zero (to
2973  * indicate complete success) or a negative error code.  After that
2974  * callback returns, the driver which issued the transfer request may
2975  * deallocate the associated memory; it's no longer in use by any SPI
2976  * core or controller driver code.
2977  *
2978  * Note that although all messages to a spi_device are handled in
2979  * FIFO order, messages may go to different devices in other orders.
2980  * Some device might be higher priority, or have various "hard" access
2981  * time requirements, for example.
2982  *
2983  * On detection of any fault during the transfer, processing of
2984  * the entire message is aborted, and the device is deselected.
2985  * Until returning from the associated message completion callback,
2986  * no other spi_message queued to that device will be processed.
2987  * (This rule applies equally to all the synchronous transfer calls,
2988  * which are wrappers around this core asynchronous primitive.)
2989  *
2990  * Return: zero on success, else a negative error code.
2991  */
2992 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
2993 {
2994         struct spi_controller *ctlr = spi->controller;
2995         int ret;
2996         unsigned long flags;
2997
2998         ret = __spi_validate(spi, message);
2999         if (ret != 0)
3000                 return ret;
3001
3002         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3003
3004         ret = __spi_async(spi, message);
3005
3006         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3007
3008         return ret;
3009
3010 }
3011 EXPORT_SYMBOL_GPL(spi_async_locked);
3012
3013
3014 int spi_flash_read(struct spi_device *spi,
3015                    struct spi_flash_read_message *msg)
3016
3017 {
3018         struct spi_controller *master = spi->controller;
3019         struct device *rx_dev = NULL;
3020         int ret;
3021
3022         if ((msg->opcode_nbits == SPI_NBITS_DUAL ||
3023              msg->addr_nbits == SPI_NBITS_DUAL) &&
3024             !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
3025                 return -EINVAL;
3026         if ((msg->opcode_nbits == SPI_NBITS_QUAD ||
3027              msg->addr_nbits == SPI_NBITS_QUAD) &&
3028             !(spi->mode & SPI_TX_QUAD))
3029                 return -EINVAL;
3030         if (msg->data_nbits == SPI_NBITS_DUAL &&
3031             !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
3032                 return -EINVAL;
3033         if (msg->data_nbits == SPI_NBITS_QUAD &&
3034             !(spi->mode &  SPI_RX_QUAD))
3035                 return -EINVAL;
3036
3037         if (master->auto_runtime_pm) {
3038                 ret = pm_runtime_get_sync(master->dev.parent);
3039                 if (ret < 0) {
3040                         dev_err(&master->dev, "Failed to power device: %d\n",
3041                                 ret);
3042                         return ret;
3043                 }
3044         }
3045
3046         mutex_lock(&master->bus_lock_mutex);
3047         mutex_lock(&master->io_mutex);
3048         if (master->dma_rx && master->spi_flash_can_dma(spi, msg)) {
3049                 rx_dev = master->dma_rx->device->dev;
3050                 ret = spi_map_buf(master, rx_dev, &msg->rx_sg,
3051                                   msg->buf, msg->len,
3052                                   DMA_FROM_DEVICE);
3053                 if (!ret)
3054                         msg->cur_msg_mapped = true;
3055         }
3056         ret = master->spi_flash_read(spi, msg);
3057         if (msg->cur_msg_mapped)
3058                 spi_unmap_buf(master, rx_dev, &msg->rx_sg,
3059                               DMA_FROM_DEVICE);
3060         mutex_unlock(&master->io_mutex);
3061         mutex_unlock(&master->bus_lock_mutex);
3062
3063         if (master->auto_runtime_pm)
3064                 pm_runtime_put(master->dev.parent);
3065
3066         return ret;
3067 }
3068 EXPORT_SYMBOL_GPL(spi_flash_read);
3069
3070 /*-------------------------------------------------------------------------*/
3071
3072 /* Utility methods for SPI protocol drivers, layered on
3073  * top of the core.  Some other utility methods are defined as
3074  * inline functions.
3075  */
3076
3077 static void spi_complete(void *arg)
3078 {
3079         complete(arg);
3080 }
3081
3082 static int __spi_sync(struct spi_device *spi, struct spi_message *message)
3083 {
3084         DECLARE_COMPLETION_ONSTACK(done);
3085         int status;
3086         struct spi_controller *ctlr = spi->controller;
3087         unsigned long flags;
3088
3089         status = __spi_validate(spi, message);
3090         if (status != 0)
3091                 return status;
3092
3093         message->complete = spi_complete;
3094         message->context = &done;
3095         message->spi = spi;
3096
3097         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_sync);
3098         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
3099
3100         /* If we're not using the legacy transfer method then we will
3101          * try to transfer in the calling context so special case.
3102          * This code would be less tricky if we could remove the
3103          * support for driver implemented message queues.
3104          */
3105         if (ctlr->transfer == spi_queued_transfer) {
3106                 spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3107
3108                 trace_spi_message_submit(message);
3109
3110                 status = __spi_queued_transfer(spi, message, false);
3111
3112                 spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3113         } else {
3114                 status = spi_async_locked(spi, message);
3115         }
3116
3117         if (status == 0) {
3118                 /* Push out the messages in the calling context if we
3119                  * can.
3120                  */
3121                 if (ctlr->transfer == spi_queued_transfer) {
3122                         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
3123                                                        spi_sync_immediate);
3124                         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
3125                                                        spi_sync_immediate);
3126                         __spi_pump_messages(ctlr, false);
3127                 }
3128
3129                 wait_for_completion(&done);
3130                 status = message->status;
3131         }
3132         message->context = NULL;
3133         return status;
3134 }
3135
3136 /**
3137  * spi_sync - blocking/synchronous SPI data transfers
3138  * @spi: device with which data will be exchanged
3139  * @message: describes the data transfers
3140  * Context: can sleep
3141  *
3142  * This call may only be used from a context that may sleep.  The sleep
3143  * is non-interruptible, and has no timeout.  Low-overhead controller
3144  * drivers may DMA directly into and out of the message buffers.
3145  *
3146  * Note that the SPI device's chip select is active during the message,
3147  * and then is normally disabled between messages.  Drivers for some
3148  * frequently-used devices may want to minimize costs of selecting a chip,
3149  * by leaving it selected in anticipation that the next message will go
3150  * to the same chip.  (That may increase power usage.)
3151  *
3152  * Also, the caller is guaranteeing that the memory associated with the
3153  * message will not be freed before this call returns.
3154  *
3155  * Return: zero on success, else a negative error code.
3156  */
3157 int spi_sync(struct spi_device *spi, struct spi_message *message)
3158 {
3159         int ret;
3160
3161         mutex_lock(&spi->controller->bus_lock_mutex);
3162         ret = __spi_sync(spi, message);
3163         mutex_unlock(&spi->controller->bus_lock_mutex);
3164
3165         return ret;
3166 }
3167 EXPORT_SYMBOL_GPL(spi_sync);
3168
3169 /**
3170  * spi_sync_locked - version of spi_sync with exclusive bus usage
3171  * @spi: device with which data will be exchanged
3172  * @message: describes the data transfers
3173  * Context: can sleep
3174  *
3175  * This call may only be used from a context that may sleep.  The sleep
3176  * is non-interruptible, and has no timeout.  Low-overhead controller
3177  * drivers may DMA directly into and out of the message buffers.
3178  *
3179  * This call should be used by drivers that require exclusive access to the
3180  * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
3181  * be released by a spi_bus_unlock call when the exclusive access is over.
3182  *
3183  * Return: zero on success, else a negative error code.
3184  */
3185 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
3186 {
3187         return __spi_sync(spi, message);
3188 }
3189 EXPORT_SYMBOL_GPL(spi_sync_locked);
3190
3191 /**
3192  * spi_bus_lock - obtain a lock for exclusive SPI bus usage
3193  * @ctlr: SPI bus master that should be locked for exclusive bus access
3194  * Context: can sleep
3195  *
3196  * This call may only be used from a context that may sleep.  The sleep
3197  * is non-interruptible, and has no timeout.
3198  *
3199  * This call should be used by drivers that require exclusive access to the
3200  * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
3201  * exclusive access is over. Data transfer must be done by spi_sync_locked
3202  * and spi_async_locked calls when the SPI bus lock is held.
3203  *
3204  * Return: always zero.
3205  */
3206 int spi_bus_lock(struct spi_controller *ctlr)
3207 {
3208         unsigned long flags;
3209
3210         mutex_lock(&ctlr->bus_lock_mutex);
3211
3212         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3213         ctlr->bus_lock_flag = 1;
3214         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3215
3216         /* mutex remains locked until spi_bus_unlock is called */
3217
3218         return 0;
3219 }
3220 EXPORT_SYMBOL_GPL(spi_bus_lock);
3221
3222 /**
3223  * spi_bus_unlock - release the lock for exclusive SPI bus usage
3224  * @ctlr: SPI bus master that was locked for exclusive bus access
3225  * Context: can sleep
3226  *
3227  * This call may only be used from a context that may sleep.  The sleep
3228  * is non-interruptible, and has no timeout.
3229  *
3230  * This call releases an SPI bus lock previously obtained by an spi_bus_lock
3231  * call.
3232  *
3233  * Return: always zero.
3234  */
3235 int spi_bus_unlock(struct spi_controller *ctlr)
3236 {
3237         ctlr->bus_lock_flag = 0;
3238
3239         mutex_unlock(&ctlr->bus_lock_mutex);
3240
3241         return 0;
3242 }
3243 EXPORT_SYMBOL_GPL(spi_bus_unlock);
3244
3245 /* portable code must never pass more than 32 bytes */
3246 #define SPI_BUFSIZ      max(32, SMP_CACHE_BYTES)
3247
3248 static u8       *buf;
3249
3250 /**
3251  * spi_write_then_read - SPI synchronous write followed by read
3252  * @spi: device with which data will be exchanged
3253  * @txbuf: data to be written (need not be dma-safe)
3254  * @n_tx: size of txbuf, in bytes
3255  * @rxbuf: buffer into which data will be read (need not be dma-safe)
3256  * @n_rx: size of rxbuf, in bytes
3257  * Context: can sleep
3258  *
3259  * This performs a half duplex MicroWire style transaction with the
3260  * device, sending txbuf and then reading rxbuf.  The return value
3261  * is zero for success, else a negative errno status code.
3262  * This call may only be used from a context that may sleep.
3263  *
3264  * Parameters to this routine are always copied using a small buffer;
3265  * portable code should never use this for more than 32 bytes.
3266  * Performance-sensitive or bulk transfer code should instead use
3267  * spi_{async,sync}() calls with dma-safe buffers.
3268  *
3269  * Return: zero on success, else a negative error code.
3270  */
3271 int spi_write_then_read(struct spi_device *spi,
3272                 const void *txbuf, unsigned n_tx,
3273                 void *rxbuf, unsigned n_rx)
3274 {
3275         static DEFINE_MUTEX(lock);
3276
3277         int                     status;
3278         struct spi_message      message;
3279         struct spi_transfer     x[2];
3280         u8                      *local_buf;
3281
3282         /* Use preallocated DMA-safe buffer if we can.  We can't avoid
3283          * copying here, (as a pure convenience thing), but we can
3284          * keep heap costs out of the hot path unless someone else is
3285          * using the pre-allocated buffer or the transfer is too large.
3286          */
3287         if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
3288                 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
3289                                     GFP_KERNEL | GFP_DMA);
3290                 if (!local_buf)
3291                         return -ENOMEM;
3292         } else {
3293                 local_buf = buf;
3294         }
3295
3296         spi_message_init(&message);
3297         memset(x, 0, sizeof(x));
3298         if (n_tx) {
3299                 x[0].len = n_tx;
3300                 spi_message_add_tail(&x[0], &message);
3301         }
3302         if (n_rx) {
3303                 x[1].len = n_rx;
3304                 spi_message_add_tail(&x[1], &message);
3305         }
3306
3307         memcpy(local_buf, txbuf, n_tx);
3308         x[0].tx_buf = local_buf;
3309         x[1].rx_buf = local_buf + n_tx;
3310
3311         /* do the i/o */
3312         status = spi_sync(spi, &message);
3313         if (status == 0)
3314                 memcpy(rxbuf, x[1].rx_buf, n_rx);
3315
3316         if (x[0].tx_buf == buf)
3317                 mutex_unlock(&lock);
3318         else
3319                 kfree(local_buf);
3320
3321         return status;
3322 }
3323 EXPORT_SYMBOL_GPL(spi_write_then_read);
3324
3325 /*-------------------------------------------------------------------------*/
3326
3327 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
3328 static int __spi_of_device_match(struct device *dev, void *data)
3329 {
3330         return dev->of_node == data;
3331 }
3332
3333 /* must call put_device() when done with returned spi_device device */
3334 static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
3335 {
3336         struct device *dev = bus_find_device(&spi_bus_type, NULL, node,
3337                                                 __spi_of_device_match);
3338         return dev ? to_spi_device(dev) : NULL;
3339 }
3340
3341 static int __spi_of_controller_match(struct device *dev, const void *data)
3342 {
3343         return dev->of_node == data;
3344 }
3345
3346 /* the spi controllers are not using spi_bus, so we find it with another way */
3347 static struct spi_controller *of_find_spi_controller_by_node(struct device_node *node)
3348 {
3349         struct device *dev;
3350
3351         dev = class_find_device(&spi_master_class, NULL, node,
3352                                 __spi_of_controller_match);
3353         if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
3354                 dev = class_find_device(&spi_slave_class, NULL, node,
3355                                         __spi_of_controller_match);
3356         if (!dev)
3357                 return NULL;
3358
3359         /* reference got in class_find_device */
3360         return container_of(dev, struct spi_controller, dev);
3361 }
3362
3363 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
3364                          void *arg)
3365 {
3366         struct of_reconfig_data *rd = arg;
3367         struct spi_controller *ctlr;
3368         struct spi_device *spi;
3369
3370         switch (of_reconfig_get_state_change(action, arg)) {
3371         case OF_RECONFIG_CHANGE_ADD:
3372                 ctlr = of_find_spi_controller_by_node(rd->dn->parent);
3373                 if (ctlr == NULL)
3374                         return NOTIFY_OK;       /* not for us */
3375
3376                 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
3377                         put_device(&ctlr->dev);
3378                         return NOTIFY_OK;
3379                 }
3380
3381                 spi = of_register_spi_device(ctlr, rd->dn);
3382                 put_device(&ctlr->dev);
3383
3384                 if (IS_ERR(spi)) {
3385                         pr_err("%s: failed to create for '%pOF'\n",
3386                                         __func__, rd->dn);
3387                         of_node_clear_flag(rd->dn, OF_POPULATED);
3388                         return notifier_from_errno(PTR_ERR(spi));
3389                 }
3390                 break;
3391
3392         case OF_RECONFIG_CHANGE_REMOVE:
3393                 /* already depopulated? */
3394                 if (!of_node_check_flag(rd->dn, OF_POPULATED))
3395                         return NOTIFY_OK;
3396
3397                 /* find our device by node */
3398                 spi = of_find_spi_device_by_node(rd->dn);
3399                 if (spi == NULL)
3400                         return NOTIFY_OK;       /* no? not meant for us */
3401
3402                 /* unregister takes one ref away */
3403                 spi_unregister_device(spi);
3404
3405                 /* and put the reference of the find */
3406                 put_device(&spi->dev);
3407                 break;
3408         }
3409
3410         return NOTIFY_OK;
3411 }
3412
3413 static struct notifier_block spi_of_notifier = {
3414         .notifier_call = of_spi_notify,
3415 };
3416 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3417 extern struct notifier_block spi_of_notifier;
3418 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3419
3420 #if IS_ENABLED(CONFIG_ACPI)
3421 static int spi_acpi_controller_match(struct device *dev, const void *data)
3422 {
3423         return ACPI_COMPANION(dev->parent) == data;
3424 }
3425
3426 static int spi_acpi_device_match(struct device *dev, void *data)
3427 {
3428         return ACPI_COMPANION(dev) == data;
3429 }
3430
3431 static struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev)
3432 {
3433         struct device *dev;
3434
3435         dev = class_find_device(&spi_master_class, NULL, adev,
3436                                 spi_acpi_controller_match);
3437         if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
3438                 dev = class_find_device(&spi_slave_class, NULL, adev,
3439                                         spi_acpi_controller_match);
3440         if (!dev)
3441                 return NULL;
3442
3443         return container_of(dev, struct spi_controller, dev);
3444 }
3445
3446 static struct spi_device *acpi_spi_find_device_by_adev(struct acpi_device *adev)
3447 {
3448         struct device *dev;
3449
3450         dev = bus_find_device(&spi_bus_type, NULL, adev, spi_acpi_device_match);
3451
3452         return dev ? to_spi_device(dev) : NULL;
3453 }
3454
3455 static int acpi_spi_notify(struct notifier_block *nb, unsigned long value,
3456                            void *arg)
3457 {
3458         struct acpi_device *adev = arg;
3459         struct spi_controller *ctlr;
3460         struct spi_device *spi;
3461
3462         switch (value) {
3463         case ACPI_RECONFIG_DEVICE_ADD:
3464                 ctlr = acpi_spi_find_controller_by_adev(adev->parent);
3465                 if (!ctlr)
3466                         break;
3467
3468                 acpi_register_spi_device(ctlr, adev);
3469                 put_device(&ctlr->dev);
3470                 break;
3471         case ACPI_RECONFIG_DEVICE_REMOVE:
3472                 if (!acpi_device_enumerated(adev))
3473                         break;
3474
3475                 spi = acpi_spi_find_device_by_adev(adev);
3476                 if (!spi)
3477                         break;
3478
3479                 spi_unregister_device(spi);
3480                 put_device(&spi->dev);
3481                 break;
3482         }
3483
3484         return NOTIFY_OK;
3485 }
3486
3487 static struct notifier_block spi_acpi_notifier = {
3488         .notifier_call = acpi_spi_notify,
3489 };
3490 #else
3491 extern struct notifier_block spi_acpi_notifier;
3492 #endif
3493
3494 static int __init spi_init(void)
3495 {
3496         int     status;
3497
3498         buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
3499         if (!buf) {
3500                 status = -ENOMEM;
3501                 goto err0;
3502         }
3503
3504         status = bus_register(&spi_bus_type);
3505         if (status < 0)
3506                 goto err1;
3507
3508         status = class_register(&spi_master_class);
3509         if (status < 0)
3510                 goto err2;
3511
3512         if (IS_ENABLED(CONFIG_SPI_SLAVE)) {
3513                 status = class_register(&spi_slave_class);
3514                 if (status < 0)
3515                         goto err3;
3516         }
3517
3518         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
3519                 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
3520         if (IS_ENABLED(CONFIG_ACPI))
3521                 WARN_ON(acpi_reconfig_notifier_register(&spi_acpi_notifier));
3522
3523         return 0;
3524
3525 err3:
3526         class_unregister(&spi_master_class);
3527 err2:
3528         bus_unregister(&spi_bus_type);
3529 err1:
3530         kfree(buf);
3531         buf = NULL;
3532 err0:
3533         return status;
3534 }
3535
3536 /* board_info is normally registered in arch_initcall(),
3537  * but even essential drivers wait till later
3538  *
3539  * REVISIT only boardinfo really needs static linking. the rest (device and
3540  * driver registration) _could_ be dynamically linked (modular) ... costs
3541  * include needing to have boardinfo data structures be much more public.
3542  */
3543 postcore_initcall(spi_init);
3544