drivers/spi/spi.c

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