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                 /* Emptry 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 opertion 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
 514         spin_lock_init(&spi->statistics.lock);
 515
 516         device_initialize(&spi->dev);
 517         return spi;
 518 }
 519 EXPORT_SYMBOL_GPL(spi_alloc_device);
 520
 521 static void spi_dev_set_name(struct spi_device *spi)
 522 {
 523         struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
 524
 525         if (adev) {
 526                 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
 527                 return;
 528         }
 529
 530         dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->controller->dev),
 531                      spi->chip_select);
 532 }
 533
 534 static int spi_dev_check(struct device *dev, void *data)
 535 {
 536         struct spi_device *spi = to_spi_device(dev);
 537         struct spi_device *new_spi = data;
 538
 539         if (spi->controller == new_spi->controller &&
 540             spi->chip_select == new_spi->chip_select)
 541                 return -EBUSY;
 542         return 0;
 543 }
 544
 545 /**
 546  * spi_add_device - Add spi_device allocated with spi_alloc_device
 547  * @spi: spi_device to register
 548  *
 549  * Companion function to spi_alloc_device.  Devices allocated with
 550  * spi_alloc_device can be added onto the spi bus with this function.
 551  *
 552  * Return: 0 on success; negative errno on failure
 553  */
 554 int spi_add_device(struct spi_device *spi)
 555 {
 556         static DEFINE_MUTEX(spi_add_lock);
 557         struct spi_controller *ctlr = spi->controller;
 558         struct device *dev = ctlr->dev.parent;
 559         int status;
 560
 561         /* Chipselects are numbered 0..max; validate. */
 562         if (spi->chip_select >= ctlr->num_chipselect) {
 563                 dev_err(dev, "cs%d >= max %d\n", spi->chip_select,
 564                         ctlr->num_chipselect);
 565                 return -EINVAL;
 566         }
 567
 568         /* Set the bus ID string */
 569         spi_dev_set_name(spi);
 570
 571         /* We need to make sure there's no other device with this
 572          * chipselect **BEFORE** we call setup(), else we'll trash
 573          * its configuration.  Lock against concurrent add() calls.
 574          */
 575         mutex_lock(&spi_add_lock);
 576
 577         status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
 578         if (status) {
 579                 dev_err(dev, "chipselect %d already in use\n",
 580                                 spi->chip_select);
 581                 goto done;
 582         }
 583
 584         /* Descriptors take precedence */
 585         if (ctlr->cs_gpiods)
 586                 spi->cs_gpiod = ctlr->cs_gpiods[spi->chip_select];
 587         else if (ctlr->cs_gpios)
 588                 spi->cs_gpio = ctlr->cs_gpios[spi->chip_select];
 589
 590         /* Drivers may modify this initial i/o setup, but will
 591          * normally rely on the device being setup.  Devices
 592          * using SPI_CS_HIGH can't coexist well otherwise...
 593          */
 594         status = spi_setup(spi);
 595         if (status < 0) {
 596                 dev_err(dev, "can't setup %s, status %d\n",
 597                                 dev_name(&spi->dev), status);
 598                 goto done;
 599         }
 600
 601         /* Device may be bound to an active driver when this returns */
 602         status = device_add(&spi->dev);
 603         if (status < 0)
 604                 dev_err(dev, "can't add %s, status %d\n",
 605                                 dev_name(&spi->dev), status);
 606         else
 607                 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
 608
 609 done:
 610         mutex_unlock(&spi_add_lock);
 611         return status;
 612 }
 613 EXPORT_SYMBOL_GPL(spi_add_device);
 614
 615 /**
 616  * spi_new_device - instantiate one new SPI device
 617  * @ctlr: Controller to which device is connected
 618  * @chip: Describes the SPI device
 619  * Context: can sleep
 620  *
 621  * On typical mainboards, this is purely internal; and it's not needed
 622  * after board init creates the hard-wired devices.  Some development
 623  * platforms may not be able to use spi_register_board_info though, and
 624  * this is exported so that for example a USB or parport based adapter
 625  * driver could add devices (which it would learn about out-of-band).
 626  *
 627  * Return: the new device, or NULL.
 628  */
 629 struct spi_device *spi_new_device(struct spi_controller *ctlr,
 630                                   struct spi_board_info *chip)
 631 {
 632         struct spi_device       *proxy;
 633         int                     status;
 634
 635         /* NOTE:  caller did any chip->bus_num checks necessary.
 636          *
 637          * Also, unless we change the return value convention to use
 638          * error-or-pointer (not NULL-or-pointer), troubleshootability
 639          * suggests syslogged diagnostics are best here (ugh).
 640          */
 641
 642         proxy = spi_alloc_device(ctlr);
 643         if (!proxy)
 644                 return NULL;
 645
 646         WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
 647
 648         proxy->chip_select = chip->chip_select;
 649         proxy->max_speed_hz = chip->max_speed_hz;
 650         proxy->mode = chip->mode;
 651         proxy->irq = chip->irq;
 652         strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
 653         proxy->dev.platform_data = (void *) chip->platform_data;
 654         proxy->controller_data = chip->controller_data;
 655         proxy->controller_state = NULL;
 656
 657         if (chip->properties) {
 658                 status = device_add_properties(&proxy->dev, chip->properties);
 659                 if (status) {
 660                         dev_err(&ctlr->dev,
 661                                 "failed to add properties to '%s': %d\n",
 662                                 chip->modalias, status);
 663                         goto err_dev_put;
 664                 }
 665         }
 666
 667         status = spi_add_device(proxy);
 668         if (status < 0)
 669                 goto err_remove_props;
 670
 671         return proxy;
 672
 673 err_remove_props:
 674         if (chip->properties)
 675                 device_remove_properties(&proxy->dev);
 676 err_dev_put:
 677         spi_dev_put(proxy);
 678         return NULL;
 679 }
 680 EXPORT_SYMBOL_GPL(spi_new_device);
 681
 682 /**
 683  * spi_unregister_device - unregister a single SPI device
 684  * @spi: spi_device to unregister
 685  *
 686  * Start making the passed SPI device vanish. Normally this would be handled
 687  * by spi_unregister_controller().
 688  */
 689 void spi_unregister_device(struct spi_device *spi)
 690 {
 691         if (!spi)
 692                 return;
 693
 694         if (spi->dev.of_node) {
 695                 of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
 696                 of_node_put(spi->dev.of_node);
 697         }
 698         if (ACPI_COMPANION(&spi->dev))
 699                 acpi_device_clear_enumerated(ACPI_COMPANION(&spi->dev));
 700         device_unregister(&spi->dev);
 701 }
 702 EXPORT_SYMBOL_GPL(spi_unregister_device);
 703
 704 static void spi_match_controller_to_boardinfo(struct spi_controller *ctlr,
 705                                               struct spi_board_info *bi)
 706 {
 707         struct spi_device *dev;
 708
 709         if (ctlr->bus_num != bi->bus_num)
 710                 return;
 711
 712         dev = spi_new_device(ctlr, bi);
 713         if (!dev)
 714                 dev_err(ctlr->dev.parent, "can't create new device for %s\n",
 715                         bi->modalias);
 716 }
 717
 718 /**
 719  * spi_register_board_info - register SPI devices for a given board
 720  * @info: array of chip descriptors
 721  * @n: how many descriptors are provided
 722  * Context: can sleep
 723  *
 724  * Board-specific early init code calls this (probably during arch_initcall)
 725  * with segments of the SPI device table.  Any device nodes are created later,
 726  * after the relevant parent SPI controller (bus_num) is defined.  We keep
 727  * this table of devices forever, so that reloading a controller driver will
 728  * not make Linux forget about these hard-wired devices.
 729  *
 730  * Other code can also call this, e.g. a particular add-on board might provide
 731  * SPI devices through its expansion connector, so code initializing that board
 732  * would naturally declare its SPI devices.
 733  *
 734  * The board info passed can safely be __initdata ... but be careful of
 735  * any embedded pointers (platform_data, etc), they're copied as-is.
 736  * Device properties are deep-copied though.
 737  *
 738  * Return: zero on success, else a negative error code.
 739  */
 740 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
 741 {
 742         struct boardinfo *bi;
 743         int i;
 744
 745         if (!n)
 746                 return 0;
 747
 748         bi = kcalloc(n, sizeof(*bi), GFP_KERNEL);
 749         if (!bi)
 750                 return -ENOMEM;
 751
 752         for (i = 0; i < n; i++, bi++, info++) {
 753                 struct spi_controller *ctlr;
 754
 755                 memcpy(&bi->board_info, info, sizeof(*info));
 756                 if (info->properties) {
 757                         bi->board_info.properties =
 758                                         property_entries_dup(info->properties);
 759                         if (IS_ERR(bi->board_info.properties))
 760                                 return PTR_ERR(bi->board_info.properties);
 761                 }
 762
 763                 mutex_lock(&board_lock);
 764                 list_add_tail(&bi->list, &board_list);
 765                 list_for_each_entry(ctlr, &spi_controller_list, list)
 766                         spi_match_controller_to_boardinfo(ctlr,
 767                                                           &bi->board_info);
 768                 mutex_unlock(&board_lock);
 769         }
 770
 771         return 0;
 772 }
 773
 774 /*-------------------------------------------------------------------------*/
 775
 776 static void spi_set_cs(struct spi_device *spi, bool enable)
 777 {
 778         if (spi->mode & SPI_CS_HIGH)
 779                 enable = !enable;
 780
 781         if (spi->cs_gpiod || gpio_is_valid(spi->cs_gpio)) {
 782                 /*
 783                  * Honour the SPI_NO_CS flag and invert the enable line, as
 784                  * active low is default for SPI. Execution paths that handle
 785                  * polarity inversion in gpiolib (such as device tree) will
 786                  * enforce active high using the SPI_CS_HIGH resulting in a
 787                  * double inversion through the code above.
 788                  */
 789                 if (!(spi->mode & SPI_NO_CS)) {
 790                         if (spi->cs_gpiod)
 791                                 gpiod_set_value_cansleep(spi->cs_gpiod,
 792                                                          !enable);
 793                         else
 794                                 gpio_set_value_cansleep(spi->cs_gpio, !enable);
 795                 }
 796                 /* Some SPI masters need both GPIO CS & slave_select */
 797                 if ((spi->controller->flags & SPI_MASTER_GPIO_SS) &&
 798                     spi->controller->set_cs)
 799                         spi->controller->set_cs(spi, !enable);
 800         } else if (spi->controller->set_cs) {
 801                 spi->controller->set_cs(spi, !enable);
 802         }
 803 }
 804
 805 #ifdef CONFIG_HAS_DMA
 806 int spi_map_buf(struct spi_controller *ctlr, struct device *dev,
 807                 struct sg_table *sgt, void *buf, size_t len,
 808                 enum dma_data_direction dir)
 809 {
 810         const bool vmalloced_buf = is_vmalloc_addr(buf);
 811         unsigned int max_seg_size = dma_get_max_seg_size(dev);
 812 #ifdef CONFIG_HIGHMEM
 813         const bool kmap_buf = ((unsigned long)buf >= PKMAP_BASE &&
 814                                 (unsigned long)buf < (PKMAP_BASE +
 815                                         (LAST_PKMAP * PAGE_SIZE)));
 816 #else
 817         const bool kmap_buf = false;
 818 #endif
 819         int desc_len;
 820         int sgs;
 821         struct page *vm_page;
 822         struct scatterlist *sg;
 823         void *sg_buf;
 824         size_t min;
 825         int i, ret;
 826
 827         if (vmalloced_buf || kmap_buf) {
 828                 desc_len = min_t(int, max_seg_size, PAGE_SIZE);
 829                 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
 830         } else if (virt_addr_valid(buf)) {
 831                 desc_len = min_t(int, max_seg_size, ctlr->max_dma_len);
 832                 sgs = DIV_ROUND_UP(len, desc_len);
 833         } else {
 834                 return -EINVAL;
 835         }
 836
 837         ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
 838         if (ret != 0)
 839                 return ret;
 840
 841         sg = &sgt->sgl[0];
 842         for (i = 0; i < sgs; i++) {
 843
 844                 if (vmalloced_buf || kmap_buf) {
 845                         /*
 846                          * Next scatterlist entry size is the minimum between
 847                          * the desc_len and the remaining buffer length that
 848                          * fits in a page.
 849                          */
 850                         min = min_t(size_t, desc_len,
 851                                     min_t(size_t, len,
 852                                           PAGE_SIZE - offset_in_page(buf)));
 853                         if (vmalloced_buf)
 854                                 vm_page = vmalloc_to_page(buf);
 855                         else
 856                                 vm_page = kmap_to_page(buf);
 857                         if (!vm_page) {
 858                                 sg_free_table(sgt);
 859                                 return -ENOMEM;
 860                         }
 861                         sg_set_page(sg, vm_page,
 862                                     min, offset_in_page(buf));
 863                 } else {
 864                         min = min_t(size_t, len, desc_len);
 865                         sg_buf = buf;
 866                         sg_set_buf(sg, sg_buf, min);
 867                 }
 868
 869                 buf += min;
 870                 len -= min;
 871                 sg = sg_next(sg);
 872         }
 873
 874         ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
 875         if (!ret)
 876                 ret = -ENOMEM;
 877         if (ret < 0) {
 878                 sg_free_table(sgt);
 879                 return ret;
 880         }
 881
 882         sgt->nents = ret;
 883
 884         return 0;
 885 }
 886
 887 void spi_unmap_buf(struct spi_controller *ctlr, struct device *dev,
 888                    struct sg_table *sgt, enum dma_data_direction dir)
 889 {
 890         if (sgt->orig_nents) {
 891                 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
 892                 sg_free_table(sgt);
 893         }
 894 }
 895
 896 static int __spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
 897 {
 898         struct device *tx_dev, *rx_dev;
 899         struct spi_transfer *xfer;
 900         int ret;
 901
 902         if (!ctlr->can_dma)
 903                 return 0;
 904
 905         if (ctlr->dma_tx)
 906                 tx_dev = ctlr->dma_tx->device->dev;
 907         else
 908                 tx_dev = ctlr->dev.parent;
 909
 910         if (ctlr->dma_rx)
 911                 rx_dev = ctlr->dma_rx->device->dev;
 912         else
 913                 rx_dev = ctlr->dev.parent;
 914
 915         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 916                 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
 917                         continue;
 918
 919                 if (xfer->tx_buf != NULL) {
 920                         ret = spi_map_buf(ctlr, tx_dev, &xfer->tx_sg,
 921                                           (void *)xfer->tx_buf, xfer->len,
 922                                           DMA_TO_DEVICE);
 923                         if (ret != 0)
 924                                 return ret;
 925                 }
 926
 927                 if (xfer->rx_buf != NULL) {
 928                         ret = spi_map_buf(ctlr, rx_dev, &xfer->rx_sg,
 929                                           xfer->rx_buf, xfer->len,
 930                                           DMA_FROM_DEVICE);
 931                         if (ret != 0) {
 932                                 spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg,
 933                                               DMA_TO_DEVICE);
 934                                 return ret;
 935                         }
 936                 }
 937         }
 938
 939         ctlr->cur_msg_mapped = true;
 940
 941         return 0;
 942 }
 943
 944 static int __spi_unmap_msg(struct spi_controller *ctlr, struct spi_message *msg)
 945 {
 946         struct spi_transfer *xfer;
 947         struct device *tx_dev, *rx_dev;
 948
 949         if (!ctlr->cur_msg_mapped || !ctlr->can_dma)
 950                 return 0;
 951
 952         if (ctlr->dma_tx)
 953                 tx_dev = ctlr->dma_tx->device->dev;
 954         else
 955                 tx_dev = ctlr->dev.parent;
 956
 957         if (ctlr->dma_rx)
 958                 rx_dev = ctlr->dma_rx->device->dev;
 959         else
 960                 rx_dev = ctlr->dev.parent;
 961
 962         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 963                 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
 964                         continue;
 965
 966                 spi_unmap_buf(ctlr, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
 967                 spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
 968         }
 969
 970         return 0;
 971 }
 972 #else /* !CONFIG_HAS_DMA */
 973 static inline int __spi_map_msg(struct spi_controller *ctlr,
 974                                 struct spi_message *msg)
 975 {
 976         return 0;
 977 }
 978
 979 static inline int __spi_unmap_msg(struct spi_controller *ctlr,
 980                                   struct spi_message *msg)
 981 {
 982         return 0;
 983 }
 984 #endif /* !CONFIG_HAS_DMA */
 985
 986 static inline int spi_unmap_msg(struct spi_controller *ctlr,
 987                                 struct spi_message *msg)
 988 {
 989         struct spi_transfer *xfer;
 990
 991         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 992                 /*
 993                  * Restore the original value of tx_buf or rx_buf if they are
 994                  * NULL.
 995                  */
 996                 if (xfer->tx_buf == ctlr->dummy_tx)
 997                         xfer->tx_buf = NULL;
 998                 if (xfer->rx_buf == ctlr->dummy_rx)
 999                         xfer->rx_buf = NULL;
1000         }
1001
1002         return __spi_unmap_msg(ctlr, msg);
1003 }
1004
1005 static int spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
1006 {
1007         struct spi_transfer *xfer;
1008         void *tmp;
1009         unsigned int max_tx, max_rx;
1010
1011         if (ctlr->flags & (SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX)) {
1012                 max_tx = 0;
1013                 max_rx = 0;
1014
1015                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1016                         if ((ctlr->flags & SPI_CONTROLLER_MUST_TX) &&
1017                             !xfer->tx_buf)
1018                                 max_tx = max(xfer->len, max_tx);
1019                         if ((ctlr->flags & SPI_CONTROLLER_MUST_RX) &&
1020                             !xfer->rx_buf)
1021                                 max_rx = max(xfer->len, max_rx);
1022                 }
1023
1024                 if (max_tx) {
1025                         tmp = krealloc(ctlr->dummy_tx, max_tx,
1026                                        GFP_KERNEL | GFP_DMA);
1027                         if (!tmp)
1028                                 return -ENOMEM;
1029                         ctlr->dummy_tx = tmp;
1030                         memset(tmp, 0, max_tx);
1031                 }
1032
1033                 if (max_rx) {
1034                         tmp = krealloc(ctlr->dummy_rx, max_rx,
1035                                        GFP_KERNEL | GFP_DMA);
1036                         if (!tmp)
1037                                 return -ENOMEM;
1038                         ctlr->dummy_rx = tmp;
1039                 }
1040
1041                 if (max_tx || max_rx) {
1042                         list_for_each_entry(xfer, &msg->transfers,
1043                                             transfer_list) {
1044                                 if (!xfer->len)
1045                                         continue;
1046                                 if (!xfer->tx_buf)
1047                                         xfer->tx_buf = ctlr->dummy_tx;
1048                                 if (!xfer->rx_buf)
1049                                         xfer->rx_buf = ctlr->dummy_rx;
1050                         }
1051                 }
1052         }
1053
1054         return __spi_map_msg(ctlr, msg);
1055 }
1056
1057 static int spi_transfer_wait(struct spi_controller *ctlr,
1058                              struct spi_message *msg,
1059                              struct spi_transfer *xfer)
1060 {
1061         struct spi_statistics *statm = &ctlr->statistics;
1062         struct spi_statistics *stats = &msg->spi->statistics;
1063         unsigned long long ms = 1;
1064
1065         if (spi_controller_is_slave(ctlr)) {
1066                 if (wait_for_completion_interruptible(&ctlr->xfer_completion)) {
1067                         dev_dbg(&msg->spi->dev, "SPI transfer interrupted\n");
1068                         return -EINTR;
1069                 }
1070         } else {
1071                 ms = 8LL * 1000LL * xfer->len;
1072                 do_div(ms, xfer->speed_hz);
1073                 ms += ms + 200; /* some tolerance */
1074
1075                 if (ms > UINT_MAX)
1076                         ms = UINT_MAX;
1077
1078                 ms = wait_for_completion_timeout(&ctlr->xfer_completion,
1079                                                  msecs_to_jiffies(ms));
1080
1081                 if (ms == 0) {
1082                         SPI_STATISTICS_INCREMENT_FIELD(statm, timedout);
1083                         SPI_STATISTICS_INCREMENT_FIELD(stats, timedout);
1084                         dev_err(&msg->spi->dev,
1085                                 "SPI transfer timed out\n");
1086                         return -ETIMEDOUT;
1087                 }
1088         }
1089
1090         return 0;
1091 }
1092
1093 /*
1094  * spi_transfer_one_message - Default implementation of transfer_one_message()
1095  *
1096  * This is a standard implementation of transfer_one_message() for
1097  * drivers which implement a transfer_one() operation.  It provides
1098  * standard handling of delays and chip select management.
1099  */
1100 static int spi_transfer_one_message(struct spi_controller *ctlr,
1101                                     struct spi_message *msg)
1102 {
1103         struct spi_transfer *xfer;
1104         bool keep_cs = false;
1105         int ret = 0;
1106         struct spi_statistics *statm = &ctlr->statistics;
1107         struct spi_statistics *stats = &msg->spi->statistics;
1108
1109         spi_set_cs(msg->spi, true);
1110
1111         SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
1112         SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
1113
1114         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1115                 trace_spi_transfer_start(msg, xfer);
1116
1117                 spi_statistics_add_transfer_stats(statm, xfer, ctlr);
1118                 spi_statistics_add_transfer_stats(stats, xfer, ctlr);
1119
1120                 if (xfer->tx_buf || xfer->rx_buf) {
1121                         reinit_completion(&ctlr->xfer_completion);
1122
1123                         ret = ctlr->transfer_one(ctlr, msg->spi, xfer);
1124                         if (ret < 0) {
1125                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
1126                                                                errors);
1127                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
1128                                                                errors);
1129                                 dev_err(&msg->spi->dev,
1130                                         "SPI transfer failed: %d\n", ret);
1131                                 goto out;
1132                         }
1133
1134                         if (ret > 0) {
1135                                 ret = spi_transfer_wait(ctlr, msg, xfer);
1136                                 if (ret < 0)
1137                                         msg->status = ret;
1138                         }
1139                 } else {
1140                         if (xfer->len)
1141                                 dev_err(&msg->spi->dev,
1142                                         "Bufferless transfer has length %u\n",
1143                                         xfer->len);
1144                 }
1145
1146                 trace_spi_transfer_stop(msg, xfer);
1147
1148                 if (msg->status != -EINPROGRESS)
1149                         goto out;
1150
1151                 if (xfer->delay_usecs) {
1152                         u16 us = xfer->delay_usecs;
1153
1154                         if (us <= 10)
1155                                 udelay(us);
1156                         else
1157                                 usleep_range(us, us + DIV_ROUND_UP(us, 10));
1158                 }
1159
1160                 if (xfer->cs_change) {
1161                         if (list_is_last(&xfer->transfer_list,
1162                                          &msg->transfers)) {
1163                                 keep_cs = true;
1164                         } else {
1165                                 spi_set_cs(msg->spi, false);
1166                                 udelay(10);
1167                                 spi_set_cs(msg->spi, true);
1168                         }
1169                 }
1170
1171                 msg->actual_length += xfer->len;
1172         }
1173
1174 out:
1175         if (ret != 0 || !keep_cs)
1176                 spi_set_cs(msg->spi, false);
1177
1178         if (msg->status == -EINPROGRESS)
1179                 msg->status = ret;
1180
1181         if (msg->status && ctlr->handle_err)
1182                 ctlr->handle_err(ctlr, msg);
1183
1184         spi_finalize_current_message(ctlr);
1185
1186         spi_res_release(ctlr, msg);
1187
1188         return ret;
1189 }
1190
1191 /**
1192  * spi_finalize_current_transfer - report completion of a transfer
1193  * @ctlr: the controller reporting completion
1194  *
1195  * Called by SPI drivers using the core transfer_one_message()
1196  * implementation to notify it that the current interrupt driven
1197  * transfer has finished and the next one may be scheduled.
1198  */
1199 void spi_finalize_current_transfer(struct spi_controller *ctlr)
1200 {
1201         complete(&ctlr->xfer_completion);
1202 }
1203 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1204
1205 /**
1206  * __spi_pump_messages - function which processes spi message queue
1207  * @ctlr: controller to process queue for
1208  * @in_kthread: true if we are in the context of the message pump thread
1209  *
1210  * This function checks if there is any spi message in the queue that
1211  * needs processing and if so call out to the driver to initialize hardware
1212  * and transfer each message.
1213  *
1214  * Note that it is called both from the kthread itself and also from
1215  * inside spi_sync(); the queue extraction handling at the top of the
1216  * function should deal with this safely.
1217  */
1218 static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread)
1219 {
1220         unsigned long flags;
1221         bool was_busy = false;
1222         int ret;
1223
1224         /* Lock queue */
1225         spin_lock_irqsave(&ctlr->queue_lock, flags);
1226
1227         /* Make sure we are not already running a message */
1228         if (ctlr->cur_msg) {
1229                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1230                 return;
1231         }
1232
1233         /* If another context is idling the device then defer */
1234         if (ctlr->idling) {
1235                 kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1236                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1237                 return;
1238         }
1239
1240         /* Check if the queue is idle */
1241         if (list_empty(&ctlr->queue) || !ctlr->running) {
1242                 if (!ctlr->busy) {
1243                         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1244                         return;
1245                 }
1246
1247                 /* Only do teardown in the thread */
1248                 if (!in_kthread) {
1249                         kthread_queue_work(&ctlr->kworker,
1250                                            &ctlr->pump_messages);
1251                         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1252                         return;
1253                 }
1254
1255                 ctlr->busy = false;
1256                 ctlr->idling = true;
1257                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1258
1259                 kfree(ctlr->dummy_rx);
1260                 ctlr->dummy_rx = NULL;
1261                 kfree(ctlr->dummy_tx);
1262                 ctlr->dummy_tx = NULL;
1263                 if (ctlr->unprepare_transfer_hardware &&
1264                     ctlr->unprepare_transfer_hardware(ctlr))
1265                         dev_err(&ctlr->dev,
1266                                 "failed to unprepare transfer hardware\n");
1267                 if (ctlr->auto_runtime_pm) {
1268                         pm_runtime_mark_last_busy(ctlr->dev.parent);
1269                         pm_runtime_put_autosuspend(ctlr->dev.parent);
1270                 }
1271                 trace_spi_controller_idle(ctlr);
1272
1273                 spin_lock_irqsave(&ctlr->queue_lock, flags);
1274                 ctlr->idling = false;
1275                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1276                 return;
1277         }
1278
1279         /* Extract head of queue */
1280         ctlr->cur_msg =
1281                 list_first_entry(&ctlr->queue, struct spi_message, queue);
1282
1283         list_del_init(&ctlr->cur_msg->queue);
1284         if (ctlr->busy)
1285                 was_busy = true;
1286         else
1287                 ctlr->busy = true;
1288         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1289
1290         mutex_lock(&ctlr->io_mutex);
1291
1292         if (!was_busy && ctlr->auto_runtime_pm) {
1293                 ret = pm_runtime_get_sync(ctlr->dev.parent);
1294                 if (ret < 0) {
1295                         pm_runtime_put_noidle(ctlr->dev.parent);
1296                         dev_err(&ctlr->dev, "Failed to power device: %d\n",
1297                                 ret);
1298                         mutex_unlock(&ctlr->io_mutex);
1299                         return;
1300                 }
1301         }
1302
1303         if (!was_busy)
1304                 trace_spi_controller_busy(ctlr);
1305
1306         if (!was_busy && ctlr->prepare_transfer_hardware) {
1307                 ret = ctlr->prepare_transfer_hardware(ctlr);
1308                 if (ret) {
1309                         dev_err(&ctlr->dev,
1310                                 "failed to prepare transfer hardware\n");
1311
1312                         if (ctlr->auto_runtime_pm)
1313                                 pm_runtime_put(ctlr->dev.parent);
1314                         mutex_unlock(&ctlr->io_mutex);
1315                         return;
1316                 }
1317         }
1318
1319         trace_spi_message_start(ctlr->cur_msg);
1320
1321         if (ctlr->prepare_message) {
1322                 ret = ctlr->prepare_message(ctlr, ctlr->cur_msg);
1323                 if (ret) {
1324                         dev_err(&ctlr->dev, "failed to prepare message: %d\n",
1325                                 ret);
1326                         ctlr->cur_msg->status = ret;
1327                         spi_finalize_current_message(ctlr);
1328                         goto out;
1329                 }
1330                 ctlr->cur_msg_prepared = true;
1331         }
1332
1333         ret = spi_map_msg(ctlr, ctlr->cur_msg);
1334         if (ret) {
1335                 ctlr->cur_msg->status = ret;
1336                 spi_finalize_current_message(ctlr);
1337                 goto out;
1338         }
1339
1340         ret = ctlr->transfer_one_message(ctlr, ctlr->cur_msg);
1341         if (ret) {
1342                 dev_err(&ctlr->dev,
1343                         "failed to transfer one message from queue\n");
1344                 goto out;
1345         }
1346
1347 out:
1348         mutex_unlock(&ctlr->io_mutex);
1349
1350         /* Prod the scheduler in case transfer_one() was busy waiting */
1351         if (!ret)
1352                 cond_resched();
1353 }
1354
1355 /**
1356  * spi_pump_messages - kthread work function which processes spi message queue
1357  * @work: pointer to kthread work struct contained in the controller struct
1358  */
1359 static void spi_pump_messages(struct kthread_work *work)
1360 {
1361         struct spi_controller *ctlr =
1362                 container_of(work, struct spi_controller, pump_messages);
1363
1364         __spi_pump_messages(ctlr, true);
1365 }
1366
1367 static int spi_init_queue(struct spi_controller *ctlr)
1368 {
1369         struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
1370
1371         ctlr->running = false;
1372         ctlr->busy = false;
1373
1374         kthread_init_worker(&ctlr->kworker);
1375         ctlr->kworker_task = kthread_run(kthread_worker_fn, &ctlr->kworker,
1376                                          "%s", dev_name(&ctlr->dev));
1377         if (IS_ERR(ctlr->kworker_task)) {
1378                 dev_err(&ctlr->dev, "failed to create message pump task\n");
1379                 return PTR_ERR(ctlr->kworker_task);
1380         }
1381         kthread_init_work(&ctlr->pump_messages, spi_pump_messages);
1382
1383         /*
1384          * Controller config will indicate if this controller should run the
1385          * message pump with high (realtime) priority to reduce the transfer
1386          * latency on the bus by minimising the delay between a transfer
1387          * request and the scheduling of the message pump thread. Without this
1388          * setting the message pump thread will remain at default priority.
1389          */
1390         if (ctlr->rt) {
1391                 dev_info(&ctlr->dev,
1392                         "will run message pump with realtime priority\n");
1393                 sched_setscheduler(ctlr->kworker_task, SCHED_FIFO, &param);
1394         }
1395
1396         return 0;
1397 }
1398
1399 /**
1400  * spi_get_next_queued_message() - called by driver to check for queued
1401  * messages
1402  * @ctlr: the controller to check for queued messages
1403  *
1404  * If there are more messages in the queue, the next message is returned from
1405  * this call.
1406  *
1407  * Return: the next message in the queue, else NULL if the queue is empty.
1408  */
1409 struct spi_message *spi_get_next_queued_message(struct spi_controller *ctlr)
1410 {
1411         struct spi_message *next;
1412         unsigned long flags;
1413
1414         /* get a pointer to the next message, if any */
1415         spin_lock_irqsave(&ctlr->queue_lock, flags);
1416         next = list_first_entry_or_null(&ctlr->queue, struct spi_message,
1417                                         queue);
1418         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1419
1420         return next;
1421 }
1422 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1423
1424 /**
1425  * spi_finalize_current_message() - the current message is complete
1426  * @ctlr: the controller to return the message to
1427  *
1428  * Called by the driver to notify the core that the message in the front of the
1429  * queue is complete and can be removed from the queue.
1430  */
1431 void spi_finalize_current_message(struct spi_controller *ctlr)
1432 {
1433         struct spi_message *mesg;
1434         unsigned long flags;
1435         int ret;
1436
1437         spin_lock_irqsave(&ctlr->queue_lock, flags);
1438         mesg = ctlr->cur_msg;
1439         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1440
1441         spi_unmap_msg(ctlr, mesg);
1442
1443         if (ctlr->cur_msg_prepared && ctlr->unprepare_message) {
1444                 ret = ctlr->unprepare_message(ctlr, mesg);
1445                 if (ret) {
1446                         dev_err(&ctlr->dev, "failed to unprepare message: %d\n",
1447                                 ret);
1448                 }
1449         }
1450
1451         spin_lock_irqsave(&ctlr->queue_lock, flags);
1452         ctlr->cur_msg = NULL;
1453         ctlr->cur_msg_prepared = false;
1454         kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1455         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1456
1457         trace_spi_message_done(mesg);
1458
1459         mesg->state = NULL;
1460         if (mesg->complete)
1461                 mesg->complete(mesg->context);
1462 }
1463 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1464
1465 static int spi_start_queue(struct spi_controller *ctlr)
1466 {
1467         unsigned long flags;
1468
1469         spin_lock_irqsave(&ctlr->queue_lock, flags);
1470
1471         if (ctlr->running || ctlr->busy) {
1472                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1473                 return -EBUSY;
1474         }
1475
1476         ctlr->running = true;
1477         ctlr->cur_msg = NULL;
1478         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1479
1480         kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1481
1482         return 0;
1483 }
1484
1485 static int spi_stop_queue(struct spi_controller *ctlr)
1486 {
1487         unsigned long flags;
1488         unsigned limit = 500;
1489         int ret = 0;
1490
1491         spin_lock_irqsave(&ctlr->queue_lock, flags);
1492
1493         /*
1494          * This is a bit lame, but is optimized for the common execution path.
1495          * A wait_queue on the ctlr->busy could be used, but then the common
1496          * execution path (pump_messages) would be required to call wake_up or
1497          * friends on every SPI message. Do this instead.
1498          */
1499         while ((!list_empty(&ctlr->queue) || ctlr->busy) && limit--) {
1500                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1501                 usleep_range(10000, 11000);
1502                 spin_lock_irqsave(&ctlr->queue_lock, flags);
1503         }
1504
1505         if (!list_empty(&ctlr->queue) || ctlr->busy)
1506                 ret = -EBUSY;
1507         else
1508                 ctlr->running = false;
1509
1510         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1511
1512         if (ret) {
1513                 dev_warn(&ctlr->dev, "could not stop message queue\n");
1514                 return ret;
1515         }
1516         return ret;
1517 }
1518
1519 static int spi_destroy_queue(struct spi_controller *ctlr)
1520 {
1521         int ret;
1522
1523         ret = spi_stop_queue(ctlr);
1524
1525         /*
1526          * kthread_flush_worker will block until all work is done.
1527          * If the reason that stop_queue timed out is that the work will never
1528          * finish, then it does no good to call flush/stop thread, so
1529          * return anyway.
1530          */
1531         if (ret) {
1532                 dev_err(&ctlr->dev, "problem destroying queue\n");
1533                 return ret;
1534         }
1535
1536         kthread_flush_worker(&ctlr->kworker);
1537         kthread_stop(ctlr->kworker_task);
1538
1539         return 0;
1540 }
1541
1542 static int __spi_queued_transfer(struct spi_device *spi,
1543                                  struct spi_message *msg,
1544                                  bool need_pump)
1545 {
1546         struct spi_controller *ctlr = spi->controller;
1547         unsigned long flags;
1548
1549         spin_lock_irqsave(&ctlr->queue_lock, flags);
1550
1551         if (!ctlr->running) {
1552                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1553                 return -ESHUTDOWN;
1554         }
1555         msg->actual_length = 0;
1556         msg->status = -EINPROGRESS;
1557
1558         list_add_tail(&msg->queue, &ctlr->queue);
1559         if (!ctlr->busy && need_pump)
1560                 kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
1561
1562         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1563         return 0;
1564 }
1565
1566 /**
1567  * spi_queued_transfer - transfer function for queued transfers
1568  * @spi: spi device which is requesting transfer
1569  * @msg: spi message which is to handled is queued to driver queue
1570  *
1571  * Return: zero on success, else a negative error code.
1572  */
1573 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1574 {
1575         return __spi_queued_transfer(spi, msg, true);
1576 }
1577
1578 static int spi_controller_initialize_queue(struct spi_controller *ctlr)
1579 {
1580         int ret;
1581
1582         ctlr->transfer = spi_queued_transfer;
1583         if (!ctlr->transfer_one_message)
1584                 ctlr->transfer_one_message = spi_transfer_one_message;
1585
1586         /* Initialize and start queue */
1587         ret = spi_init_queue(ctlr);
1588         if (ret) {
1589                 dev_err(&ctlr->dev, "problem initializing queue\n");
1590                 goto err_init_queue;
1591         }
1592         ctlr->queued = true;
1593         ret = spi_start_queue(ctlr);
1594         if (ret) {
1595                 dev_err(&ctlr->dev, "problem starting queue\n");
1596                 goto err_start_queue;
1597         }
1598
1599         return 0;
1600
1601 err_start_queue:
1602         spi_destroy_queue(ctlr);
1603 err_init_queue:
1604         return ret;
1605 }
1606
1607 /**
1608  * spi_flush_queue - Send all pending messages in the queue from the callers'
1609  *                   context
1610  * @ctlr: controller to process queue for
1611  *
1612  * This should be used when one wants to ensure all pending messages have been
1613  * sent before doing something. Is used by the spi-mem code to make sure SPI
1614  * memory operations do not preempt regular SPI transfers that have been queued
1615  * before the spi-mem operation.
1616  */
1617 void spi_flush_queue(struct spi_controller *ctlr)
1618 {
1619         if (ctlr->transfer == spi_queued_transfer)
1620                 __spi_pump_messages(ctlr, false);
1621 }
1622
1623 /*-------------------------------------------------------------------------*/
1624
1625 #if defined(CONFIG_OF)
1626 static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
1627                            struct device_node *nc)
1628 {
1629         u32 value;
1630         int rc;
1631
1632         /* Mode (clock phase/polarity/etc.) */
1633         if (of_property_read_bool(nc, "spi-cpha"))
1634                 spi->mode |= SPI_CPHA;
1635         if (of_property_read_bool(nc, "spi-cpol"))
1636                 spi->mode |= SPI_CPOL;
1637         if (of_property_read_bool(nc, "spi-3wire"))
1638                 spi->mode |= SPI_3WIRE;
1639         if (of_property_read_bool(nc, "spi-lsb-first"))
1640                 spi->mode |= SPI_LSB_FIRST;
1641
1642         /*
1643          * For descriptors associated with the device, polarity inversion is
1644          * handled in the gpiolib, so all chip selects are "active high" in
1645          * the logical sense, the gpiolib will invert the line if need be.
1646          */
1647         if (ctlr->use_gpio_descriptors)
1648                 spi->mode |= SPI_CS_HIGH;
1649         else if (of_property_read_bool(nc, "spi-cs-high"))
1650                 spi->mode |= SPI_CS_HIGH;
1651
1652         /* Device DUAL/QUAD mode */
1653         if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1654                 switch (value) {
1655                 case 1:
1656                         break;
1657                 case 2:
1658                         spi->mode |= SPI_TX_DUAL;
1659                         break;
1660                 case 4:
1661                         spi->mode |= SPI_TX_QUAD;
1662                         break;
1663                 case 8:
1664                         spi->mode |= SPI_TX_OCTAL;
1665                         break;
1666                 default:
1667                         dev_warn(&ctlr->dev,
1668                                 "spi-tx-bus-width %d not supported\n",
1669                                 value);
1670                         break;
1671                 }
1672         }
1673
1674         if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1675                 switch (value) {
1676                 case 1:
1677                         break;
1678                 case 2:
1679                         spi->mode |= SPI_RX_DUAL;
1680                         break;
1681                 case 4:
1682                         spi->mode |= SPI_RX_QUAD;
1683                         break;
1684                 case 8:
1685                         spi->mode |= SPI_RX_OCTAL;
1686                         break;
1687                 default:
1688                         dev_warn(&ctlr->dev,
1689                                 "spi-rx-bus-width %d not supported\n",
1690                                 value);
1691                         break;
1692                 }
1693         }
1694
1695         if (spi_controller_is_slave(ctlr)) {
1696                 if (!of_node_name_eq(nc, "slave")) {
1697                         dev_err(&ctlr->dev, "%pOF is not called 'slave'\n",
1698                                 nc);
1699                         return -EINVAL;
1700                 }
1701                 return 0;
1702         }
1703
1704         /* Device address */
1705         rc = of_property_read_u32(nc, "reg", &value);
1706         if (rc) {
1707                 dev_err(&ctlr->dev, "%pOF has no valid 'reg' property (%d)\n",
1708                         nc, rc);
1709                 return rc;
1710         }
1711         spi->chip_select = value;
1712
1713         /* Device speed */
1714         rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1715         if (rc) {
1716                 dev_err(&ctlr->dev,
1717                         "%pOF has no valid 'spi-max-frequency' property (%d)\n", nc, rc);
1718                 return rc;
1719         }
1720         spi->max_speed_hz = value;
1721
1722         return 0;
1723 }
1724
1725 static struct spi_device *
1726 of_register_spi_device(struct spi_controller *ctlr, struct device_node *nc)
1727 {
1728         struct spi_device *spi;
1729         int rc;
1730
1731         /* Alloc an spi_device */
1732         spi = spi_alloc_device(ctlr);
1733         if (!spi) {
1734                 dev_err(&ctlr->dev, "spi_device alloc error for %pOF\n", nc);
1735                 rc = -ENOMEM;
1736                 goto err_out;
1737         }
1738
1739         /* Select device driver */
1740         rc = of_modalias_node(nc, spi->modalias,
1741                                 sizeof(spi->modalias));
1742         if (rc < 0) {
1743                 dev_err(&ctlr->dev, "cannot find modalias for %pOF\n", nc);
1744                 goto err_out;
1745         }
1746
1747         rc = of_spi_parse_dt(ctlr, spi, nc);
1748         if (rc)
1749                 goto err_out;
1750
1751         /* Store a pointer to the node in the device structure */
1752         of_node_get(nc);
1753         spi->dev.of_node = nc;
1754
1755         /* Register the new device */
1756         rc = spi_add_device(spi);
1757         if (rc) {
1758                 dev_err(&ctlr->dev, "spi_device register error %pOF\n", nc);
1759                 goto err_of_node_put;
1760         }
1761
1762         return spi;
1763
1764 err_of_node_put:
1765         of_node_put(nc);
1766 err_out:
1767         spi_dev_put(spi);
1768         return ERR_PTR(rc);
1769 }
1770
1771 /**
1772  * of_register_spi_devices() - Register child devices onto the SPI bus
1773  * @ctlr:       Pointer to spi_controller device
1774  *
1775  * Registers an spi_device for each child node of controller node which
1776  * represents a valid SPI slave.
1777  */
1778 static void of_register_spi_devices(struct spi_controller *ctlr)
1779 {
1780         struct spi_device *spi;
1781         struct device_node *nc;
1782
1783         if (!ctlr->dev.of_node)
1784                 return;
1785
1786         for_each_available_child_of_node(ctlr->dev.of_node, nc) {
1787                 if (of_node_test_and_set_flag(nc, OF_POPULATED))
1788                         continue;
1789                 spi = of_register_spi_device(ctlr, nc);
1790                 if (IS_ERR(spi)) {
1791                         dev_warn(&ctlr->dev,
1792                                  "Failed to create SPI device for %pOF\n", nc);
1793                         of_node_clear_flag(nc, OF_POPULATED);
1794                 }
1795         }
1796 }
1797 #else
1798 static void of_register_spi_devices(struct spi_controller *ctlr) { }
1799 #endif
1800
1801 #ifdef CONFIG_ACPI
1802 static void acpi_spi_parse_apple_properties(struct spi_device *spi)
1803 {
1804         struct acpi_device *dev = ACPI_COMPANION(&spi->dev);
1805         const union acpi_object *obj;
1806
1807         if (!x86_apple_machine)
1808                 return;
1809
1810         if (!acpi_dev_get_property(dev, "spiSclkPeriod", ACPI_TYPE_BUFFER, &obj)
1811             && obj->buffer.length >= 4)
1812                 spi->max_speed_hz  = NSEC_PER_SEC / *(u32 *)obj->buffer.pointer;
1813
1814         if (!acpi_dev_get_property(dev, "spiWordSize", ACPI_TYPE_BUFFER, &obj)
1815             && obj->buffer.length == 8)
1816                 spi->bits_per_word = *(u64 *)obj->buffer.pointer;
1817
1818         if (!acpi_dev_get_property(dev, "spiBitOrder", ACPI_TYPE_BUFFER, &obj)
1819             && obj->buffer.length == 8 && !*(u64 *)obj->buffer.pointer)
1820                 spi->mode |= SPI_LSB_FIRST;
1821
1822         if (!acpi_dev_get_property(dev, "spiSPO", ACPI_TYPE_BUFFER, &obj)
1823             && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
1824                 spi->mode |= SPI_CPOL;
1825
1826         if (!acpi_dev_get_property(dev, "spiSPH", ACPI_TYPE_BUFFER, &obj)
1827             && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
1828                 spi->mode |= SPI_CPHA;
1829 }
1830
1831 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1832 {
1833         struct spi_device *spi = data;
1834         struct spi_controller *ctlr = spi->controller;
1835
1836         if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1837                 struct acpi_resource_spi_serialbus *sb;
1838
1839                 sb = &ares->data.spi_serial_bus;
1840                 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1841                         /*
1842                          * ACPI DeviceSelection numbering is handled by the
1843                          * host controller driver in Windows and can vary
1844                          * from driver to driver. In Linux we always expect
1845                          * 0 .. max - 1 so we need to ask the driver to
1846                          * translate between the two schemes.
1847                          */
1848                         if (ctlr->fw_translate_cs) {
1849                                 int cs = ctlr->fw_translate_cs(ctlr,
1850                                                 sb->device_selection);
1851                                 if (cs < 0)
1852                                         return cs;
1853                                 spi->chip_select = cs;
1854                         } else {
1855                                 spi->chip_select = sb->device_selection;
1856                         }
1857
1858                         spi->max_speed_hz = sb->connection_speed;
1859
1860                         if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1861                                 spi->mode |= SPI_CPHA;
1862                         if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1863                                 spi->mode |= SPI_CPOL;
1864                         if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1865                                 spi->mode |= SPI_CS_HIGH;
1866                 }
1867         } else if (spi->irq < 0) {
1868                 struct resource r;
1869
1870                 if (acpi_dev_resource_interrupt(ares, 0, &r))
1871                         spi->irq = r.start;
1872         }
1873
1874         /* Always tell the ACPI core to skip this resource */
1875         return 1;
1876 }
1877
1878 static acpi_status acpi_register_spi_device(struct spi_controller *ctlr,
1879                                             struct acpi_device *adev)
1880 {
1881         struct list_head resource_list;
1882         struct spi_device *spi;
1883         int ret;
1884
1885         if (acpi_bus_get_status(adev) || !adev->status.present ||
1886             acpi_device_enumerated(adev))
1887                 return AE_OK;
1888
1889         spi = spi_alloc_device(ctlr);
1890         if (!spi) {
1891                 dev_err(&ctlr->dev, "failed to allocate SPI device for %s\n",
1892                         dev_name(&adev->dev));
1893                 return AE_NO_MEMORY;
1894         }
1895
1896         ACPI_COMPANION_SET(&spi->dev, adev);
1897         spi->irq = -1;
1898
1899         INIT_LIST_HEAD(&resource_list);
1900         ret = acpi_dev_get_resources(adev, &resource_list,
1901                                      acpi_spi_add_resource, spi);
1902         acpi_dev_free_resource_list(&resource_list);
1903
1904         acpi_spi_parse_apple_properties(spi);
1905
1906         if (ret < 0 || !spi->max_speed_hz) {
1907                 spi_dev_put(spi);
1908                 return AE_OK;
1909         }
1910
1911         acpi_set_modalias(adev, acpi_device_hid(adev), spi->modalias,
1912                           sizeof(spi->modalias));
1913
1914         if (spi->irq < 0)
1915                 spi->irq = acpi_dev_gpio_irq_get(adev, 0);
1916
1917         acpi_device_set_enumerated(adev);
1918
1919         adev->power.flags.ignore_parent = true;
1920         if (spi_add_device(spi)) {
1921                 adev->power.flags.ignore_parent = false;
1922                 dev_err(&ctlr->dev, "failed to add SPI device %s from ACPI\n",
1923                         dev_name(&adev->dev));
1924                 spi_dev_put(spi);
1925         }
1926
1927         return AE_OK;
1928 }
1929
1930 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1931                                        void *data, void **return_value)
1932 {
1933         struct spi_controller *ctlr = data;
1934         struct acpi_device *adev;
1935
1936         if (acpi_bus_get_device(handle, &adev))
1937                 return AE_OK;
1938
1939         return acpi_register_spi_device(ctlr, adev);
1940 }
1941
1942 static void acpi_register_spi_devices(struct spi_controller *ctlr)
1943 {
1944         acpi_status status;
1945         acpi_handle handle;
1946
1947         handle = ACPI_HANDLE(ctlr->dev.parent);
1948         if (!handle)
1949                 return;
1950
1951         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1952                                      acpi_spi_add_device, NULL, ctlr, NULL);
1953         if (ACPI_FAILURE(status))
1954                 dev_warn(&ctlr->dev, "failed to enumerate SPI slaves\n");
1955 }
1956 #else
1957 static inline void acpi_register_spi_devices(struct spi_controller *ctlr) {}
1958 #endif /* CONFIG_ACPI */
1959
1960 static void spi_controller_release(struct device *dev)
1961 {
1962         struct spi_controller *ctlr;
1963
1964         ctlr = container_of(dev, struct spi_controller, dev);
1965         kfree(ctlr);
1966 }
1967
1968 static struct class spi_master_class = {
1969         .name           = "spi_master",
1970         .owner          = THIS_MODULE,
1971         .dev_release    = spi_controller_release,
1972         .dev_groups     = spi_master_groups,
1973 };
1974
1975 #ifdef CONFIG_SPI_SLAVE
1976 /**
1977  * spi_slave_abort - abort the ongoing transfer request on an SPI slave
1978  *                   controller
1979  * @spi: device used for the current transfer
1980  */
1981 int spi_slave_abort(struct spi_device *spi)
1982 {
1983         struct spi_controller *ctlr = spi->controller;
1984
1985         if (spi_controller_is_slave(ctlr) && ctlr->slave_abort)
1986                 return ctlr->slave_abort(ctlr);
1987
1988         return -ENOTSUPP;
1989 }
1990 EXPORT_SYMBOL_GPL(spi_slave_abort);
1991
1992 static int match_true(struct device *dev, void *data)
1993 {
1994         return 1;
1995 }
1996
1997 static ssize_t spi_slave_show(struct device *dev,
1998                               struct device_attribute *attr, char *buf)
1999 {
2000         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2001                                                    dev);
2002         struct device *child;
2003
2004         child = device_find_child(&ctlr->dev, NULL, match_true);
2005         return sprintf(buf, "%s\n",
2006                        child ? to_spi_device(child)->modalias : NULL);
2007 }
2008
2009 static ssize_t spi_slave_store(struct device *dev,
2010                                struct device_attribute *attr, const char *buf,
2011                                size_t count)
2012 {
2013         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2014                                                    dev);
2015         struct spi_device *spi;
2016         struct device *child;
2017         char name[32];
2018         int rc;
2019
2020         rc = sscanf(buf, "%31s", name);
2021         if (rc != 1 || !name[0])
2022                 return -EINVAL;
2023
2024         child = device_find_child(&ctlr->dev, NULL, match_true);
2025         if (child) {
2026                 /* Remove registered slave */
2027                 device_unregister(child);
2028                 put_device(child);
2029         }
2030
2031         if (strcmp(name, "(null)")) {
2032                 /* Register new slave */
2033                 spi = spi_alloc_device(ctlr);
2034                 if (!spi)
2035                         return -ENOMEM;
2036
2037                 strlcpy(spi->modalias, name, sizeof(spi->modalias));
2038
2039                 rc = spi_add_device(spi);
2040                 if (rc) {
2041                         spi_dev_put(spi);
2042                         return rc;
2043                 }
2044         }
2045
2046         return count;
2047 }
2048
2049 static DEVICE_ATTR(slave, 0644, spi_slave_show, spi_slave_store);
2050
2051 static struct attribute *spi_slave_attrs[] = {
2052         &dev_attr_slave.attr,
2053         NULL,
2054 };
2055
2056 static const struct attribute_group spi_slave_group = {
2057         .attrs = spi_slave_attrs,
2058 };
2059
2060 static const struct attribute_group *spi_slave_groups[] = {
2061         &spi_controller_statistics_group,
2062         &spi_slave_group,
2063         NULL,
2064 };
2065
2066 static struct class spi_slave_class = {
2067         .name           = "spi_slave",
2068         .owner          = THIS_MODULE,
2069         .dev_release    = spi_controller_release,
2070         .dev_groups     = spi_slave_groups,
2071 };
2072 #else
2073 extern struct class spi_slave_class;    /* dummy */
2074 #endif
2075
2076 /**
2077  * __spi_alloc_controller - allocate an SPI master or slave controller
2078  * @dev: the controller, possibly using the platform_bus
2079  * @size: how much zeroed driver-private data to allocate; the pointer to this
2080  *      memory is in the driver_data field of the returned device,
2081  *      accessible with spi_controller_get_devdata().
2082  * @slave: flag indicating whether to allocate an SPI master (false) or SPI
2083  *      slave (true) controller
2084  * Context: can sleep
2085  *
2086  * This call is used only by SPI controller drivers, which are the
2087  * only ones directly touching chip registers.  It's how they allocate
2088  * an spi_controller structure, prior to calling spi_register_controller().
2089  *
2090  * This must be called from context that can sleep.
2091  *
2092  * The caller is responsible for assigning the bus number and initializing the
2093  * controller's methods before calling spi_register_controller(); and (after
2094  * errors adding the device) calling spi_controller_put() to prevent a memory
2095  * leak.
2096  *
2097  * Return: the SPI controller structure on success, else NULL.
2098  */
2099 struct spi_controller *__spi_alloc_controller(struct device *dev,
2100                                               unsigned int size, bool slave)
2101 {
2102         struct spi_controller   *ctlr;
2103
2104         if (!dev)
2105                 return NULL;
2106
2107         ctlr = kzalloc(size + sizeof(*ctlr), GFP_KERNEL);
2108         if (!ctlr)
2109                 return NULL;
2110
2111         device_initialize(&ctlr->dev);
2112         ctlr->bus_num = -1;
2113         ctlr->num_chipselect = 1;
2114         ctlr->slave = slave;
2115         if (IS_ENABLED(CONFIG_SPI_SLAVE) && slave)
2116                 ctlr->dev.class = &spi_slave_class;
2117         else
2118                 ctlr->dev.class = &spi_master_class;
2119         ctlr->dev.parent = dev;
2120         pm_suspend_ignore_children(&ctlr->dev, true);
2121         spi_controller_set_devdata(ctlr, &ctlr[1]);
2122
2123         return ctlr;
2124 }
2125 EXPORT_SYMBOL_GPL(__spi_alloc_controller);
2126
2127 #ifdef CONFIG_OF
2128 static int of_spi_register_master(struct spi_controller *ctlr)
2129 {
2130         int nb, i, *cs;
2131         struct device_node *np = ctlr->dev.of_node;
2132
2133         if (!np)
2134                 return 0;
2135
2136         nb = of_gpio_named_count(np, "cs-gpios");
2137         ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2138
2139         /* Return error only for an incorrectly formed cs-gpios property */
2140         if (nb == 0 || nb == -ENOENT)
2141                 return 0;
2142         else if (nb < 0)
2143                 return nb;
2144
2145         cs = devm_kcalloc(&ctlr->dev, ctlr->num_chipselect, sizeof(int),
2146                           GFP_KERNEL);
2147         ctlr->cs_gpios = cs;
2148
2149         if (!ctlr->cs_gpios)
2150                 return -ENOMEM;
2151
2152         for (i = 0; i < ctlr->num_chipselect; i++)
2153                 cs[i] = -ENOENT;
2154
2155         for (i = 0; i < nb; i++)
2156                 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
2157
2158         return 0;
2159 }
2160 #else
2161 static int of_spi_register_master(struct spi_controller *ctlr)
2162 {
2163         return 0;
2164 }
2165 #endif
2166
2167 /**
2168  * spi_get_gpio_descs() - grab chip select GPIOs for the master
2169  * @ctlr: The SPI master to grab GPIO descriptors for
2170  */
2171 static int spi_get_gpio_descs(struct spi_controller *ctlr)
2172 {
2173         int nb, i;
2174         struct gpio_desc **cs;
2175         struct device *dev = &ctlr->dev;
2176
2177         nb = gpiod_count(dev, "cs");
2178         ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2179
2180         /* No GPIOs at all is fine, else return the error */
2181         if (nb == 0 || nb == -ENOENT)
2182                 return 0;
2183         else if (nb < 0)
2184                 return nb;
2185
2186         cs = devm_kcalloc(dev, ctlr->num_chipselect, sizeof(*cs),
2187                           GFP_KERNEL);
2188         if (!cs)
2189                 return -ENOMEM;
2190         ctlr->cs_gpiods = cs;
2191
2192         for (i = 0; i < nb; i++) {
2193                 /*
2194                  * Most chipselects are active low, the inverted
2195                  * semantics are handled by special quirks in gpiolib,
2196                  * so initializing them GPIOD_OUT_LOW here means
2197                  * "unasserted", in most cases this will drive the physical
2198                  * line high.
2199                  */
2200                 cs[i] = devm_gpiod_get_index_optional(dev, "cs", i,
2201                                                       GPIOD_OUT_LOW);
2202                 if (IS_ERR(cs[i]))
2203                         return PTR_ERR(cs[i]);
2204
2205                 if (cs[i]) {
2206                         /*
2207                          * If we find a CS GPIO, name it after the device and
2208                          * chip select line.
2209                          */
2210                         char *gpioname;
2211
2212                         gpioname = devm_kasprintf(dev, GFP_KERNEL, "%s CS%d",
2213                                                   dev_name(dev), i);
2214                         if (!gpioname)
2215                                 return -ENOMEM;
2216                         gpiod_set_consumer_name(cs[i], gpioname);
2217                 }
2218         }
2219
2220         return 0;
2221 }
2222
2223 static int spi_controller_check_ops(struct spi_controller *ctlr)
2224 {
2225         /*
2226          * The controller may implement only the high-level SPI-memory like
2227          * operations if it does not support regular SPI transfers, and this is
2228          * valid use case.
2229          * If ->mem_ops is NULL, we request that at least one of the
2230          * ->transfer_xxx() method be implemented.
2231          */
2232         if (ctlr->mem_ops) {
2233                 if (!ctlr->mem_ops->exec_op)
2234                         return -EINVAL;
2235         } else if (!ctlr->transfer && !ctlr->transfer_one &&
2236                    !ctlr->transfer_one_message) {
2237                 return -EINVAL;
2238         }
2239
2240         return 0;
2241 }
2242
2243 /**
2244  * spi_register_controller - register SPI master or slave controller
2245  * @ctlr: initialized master, originally from spi_alloc_master() or
2246  *      spi_alloc_slave()
2247  * Context: can sleep
2248  *
2249  * SPI controllers connect to their drivers using some non-SPI bus,
2250  * such as the platform bus.  The final stage of probe() in that code
2251  * includes calling spi_register_controller() to hook up to this SPI bus glue.
2252  *
2253  * SPI controllers use board specific (often SOC specific) bus numbers,
2254  * and board-specific addressing for SPI devices combines those numbers
2255  * with chip select numbers.  Since SPI does not directly support dynamic
2256  * device identification, boards need configuration tables telling which
2257  * chip is at which address.
2258  *
2259  * This must be called from context that can sleep.  It returns zero on
2260  * success, else a negative error code (dropping the controller's refcount).
2261  * After a successful return, the caller is responsible for calling
2262  * spi_unregister_controller().
2263  *
2264  * Return: zero on success, else a negative error code.
2265  */
2266 int spi_register_controller(struct spi_controller *ctlr)
2267 {
2268         struct device           *dev = ctlr->dev.parent;
2269         struct boardinfo        *bi;
2270         int                     status;
2271         int                     id, first_dynamic;
2272
2273         if (!dev)
2274                 return -ENODEV;
2275
2276         /*
2277          * Make sure all necessary hooks are implemented before registering
2278          * the SPI controller.
2279          */
2280         status = spi_controller_check_ops(ctlr);
2281         if (status)
2282                 return status;
2283
2284         /* even if it's just one always-selected device, there must
2285          * be at least one chipselect
2286          */
2287         if (ctlr->num_chipselect == 0)
2288                 return -EINVAL;
2289         if (ctlr->bus_num >= 0) {
2290                 /* devices with a fixed bus num must check-in with the num */
2291                 mutex_lock(&board_lock);
2292                 id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
2293                         ctlr->bus_num + 1, GFP_KERNEL);
2294                 mutex_unlock(&board_lock);
2295                 if (WARN(id < 0, "couldn't get idr"))
2296                         return id == -ENOSPC ? -EBUSY : id;
2297                 ctlr->bus_num = id;
2298         } else if (ctlr->dev.of_node) {
2299                 /* allocate dynamic bus number using Linux idr */
2300                 id = of_alias_get_id(ctlr->dev.of_node, "spi");
2301                 if (id >= 0) {
2302                         ctlr->bus_num = id;
2303                         mutex_lock(&board_lock);
2304                         id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
2305                                        ctlr->bus_num + 1, GFP_KERNEL);
2306                         mutex_unlock(&board_lock);
2307                         if (WARN(id < 0, "couldn't get idr"))
2308                                 return id == -ENOSPC ? -EBUSY : id;
2309                 }
2310         }
2311         if (ctlr->bus_num < 0) {
2312                 first_dynamic = of_alias_get_highest_id("spi");
2313                 if (first_dynamic < 0)
2314                         first_dynamic = 0;
2315                 else
2316                         first_dynamic++;
2317
2318                 mutex_lock(&board_lock);
2319                 id = idr_alloc(&spi_master_idr, ctlr, first_dynamic,
2320                                0, GFP_KERNEL);
2321                 mutex_unlock(&board_lock);
2322                 if (WARN(id < 0, "couldn't get idr"))
2323                         return id;
2324                 ctlr->bus_num = id;
2325         }
2326         INIT_LIST_HEAD(&ctlr->queue);
2327         spin_lock_init(&ctlr->queue_lock);
2328         spin_lock_init(&ctlr->bus_lock_spinlock);
2329         mutex_init(&ctlr->bus_lock_mutex);
2330         mutex_init(&ctlr->io_mutex);
2331         ctlr->bus_lock_flag = 0;
2332         init_completion(&ctlr->xfer_completion);
2333         if (!ctlr->max_dma_len)
2334                 ctlr->max_dma_len = INT_MAX;
2335
2336         /* register the device, then userspace will see it.
2337          * registration fails if the bus ID is in use.
2338          */
2339         dev_set_name(&ctlr->dev, "spi%u", ctlr->bus_num);
2340
2341         if (!spi_controller_is_slave(ctlr)) {
2342                 if (ctlr->use_gpio_descriptors) {
2343                         status = spi_get_gpio_descs(ctlr);
2344                         if (status)
2345                                 return status;
2346                         /*
2347                          * A controller using GPIO descriptors always
2348                          * supports SPI_CS_HIGH if need be.
2349                          */
2350                         ctlr->mode_bits |= SPI_CS_HIGH;
2351                 } else {
2352                         /* Legacy code path for GPIOs from DT */
2353                         status = of_spi_register_master(ctlr);
2354                         if (status)
2355                                 return status;
2356                 }
2357         }
2358
2359         status = device_add(&ctlr->dev);
2360         if (status < 0) {
2361                 /* free bus id */
2362                 mutex_lock(&board_lock);
2363                 idr_remove(&spi_master_idr, ctlr->bus_num);
2364                 mutex_unlock(&board_lock);
2365                 goto done;
2366         }
2367         dev_dbg(dev, "registered %s %s\n",
2368                         spi_controller_is_slave(ctlr) ? "slave" : "master",
2369                         dev_name(&ctlr->dev));
2370
2371         /*
2372          * If we're using a queued driver, start the queue. Note that we don't
2373          * need the queueing logic if the driver is only supporting high-level
2374          * memory operations.
2375          */
2376         if (ctlr->transfer) {
2377                 dev_info(dev, "controller is unqueued, this is deprecated\n");
2378         } else if (ctlr->transfer_one || ctlr->transfer_one_message) {
2379                 status = spi_controller_initialize_queue(ctlr);
2380                 if (status) {
2381                         device_del(&ctlr->dev);
2382                         /* free bus id */
2383                         mutex_lock(&board_lock);
2384                         idr_remove(&spi_master_idr, ctlr->bus_num);
2385                         mutex_unlock(&board_lock);
2386                         goto done;
2387                 }
2388         }
2389         /* add statistics */
2390         spin_lock_init(&ctlr->statistics.lock);
2391
2392         mutex_lock(&board_lock);
2393         list_add_tail(&ctlr->list, &spi_controller_list);
2394         list_for_each_entry(bi, &board_list, list)
2395                 spi_match_controller_to_boardinfo(ctlr, &bi->board_info);
2396         mutex_unlock(&board_lock);
2397
2398         /* Register devices from the device tree and ACPI */
2399         of_register_spi_devices(ctlr);
2400         acpi_register_spi_devices(ctlr);
2401 done:
2402         return status;
2403 }
2404 EXPORT_SYMBOL_GPL(spi_register_controller);
2405
2406 static void devm_spi_unregister(struct device *dev, void *res)
2407 {
2408         spi_unregister_controller(*(struct spi_controller **)res);
2409 }
2410
2411 /**
2412  * devm_spi_register_controller - register managed SPI master or slave
2413  *      controller
2414  * @dev:    device managing SPI controller
2415  * @ctlr: initialized controller, originally from spi_alloc_master() or
2416  *      spi_alloc_slave()
2417  * Context: can sleep
2418  *
2419  * Register a SPI device as with spi_register_controller() which will
2420  * automatically be unregistered and freed.
2421  *
2422  * Return: zero on success, else a negative error code.
2423  */
2424 int devm_spi_register_controller(struct device *dev,
2425                                  struct spi_controller *ctlr)
2426 {
2427         struct spi_controller **ptr;
2428         int ret;
2429
2430         ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
2431         if (!ptr)
2432                 return -ENOMEM;
2433
2434         ret = spi_register_controller(ctlr);
2435         if (!ret) {
2436                 *ptr = ctlr;
2437                 devres_add(dev, ptr);
2438         } else {
2439                 devres_free(ptr);
2440         }
2441
2442         return ret;
2443 }
2444 EXPORT_SYMBOL_GPL(devm_spi_register_controller);
2445
2446 static int __unregister(struct device *dev, void *null)
2447 {
2448         spi_unregister_device(to_spi_device(dev));
2449         return 0;
2450 }
2451
2452 /**
2453  * spi_unregister_controller - unregister SPI master or slave controller
2454  * @ctlr: the controller being unregistered
2455  * Context: can sleep
2456  *
2457  * This call is used only by SPI controller drivers, which are the
2458  * only ones directly touching chip registers.
2459  *
2460  * This must be called from context that can sleep.
2461  *
2462  * Note that this function also drops a reference to the controller.
2463  */
2464 void spi_unregister_controller(struct spi_controller *ctlr)
2465 {
2466         struct spi_controller *found;
2467         int id = ctlr->bus_num;
2468         int dummy;
2469
2470         /* First make sure that this controller was ever added */
2471         mutex_lock(&board_lock);
2472         found = idr_find(&spi_master_idr, id);
2473         mutex_unlock(&board_lock);
2474         if (ctlr->queued) {
2475                 if (spi_destroy_queue(ctlr))
2476                         dev_err(&ctlr->dev, "queue remove failed\n");
2477         }
2478         mutex_lock(&board_lock);
2479         list_del(&ctlr->list);
2480         mutex_unlock(&board_lock);
2481
2482         dummy = device_for_each_child(&ctlr->dev, NULL, __unregister);
2483         device_unregister(&ctlr->dev);
2484         /* free bus id */
2485         mutex_lock(&board_lock);
2486         if (found == ctlr)
2487                 idr_remove(&spi_master_idr, id);
2488         mutex_unlock(&board_lock);
2489 }
2490 EXPORT_SYMBOL_GPL(spi_unregister_controller);
2491
2492 int spi_controller_suspend(struct spi_controller *ctlr)
2493 {
2494         int ret;
2495
2496         /* Basically no-ops for non-queued controllers */
2497         if (!ctlr->queued)
2498                 return 0;
2499
2500         ret = spi_stop_queue(ctlr);
2501         if (ret)
2502                 dev_err(&ctlr->dev, "queue stop failed\n");
2503
2504         return ret;
2505 }
2506 EXPORT_SYMBOL_GPL(spi_controller_suspend);
2507
2508 int spi_controller_resume(struct spi_controller *ctlr)
2509 {
2510         int ret;
2511
2512         if (!ctlr->queued)
2513                 return 0;
2514
2515         ret = spi_start_queue(ctlr);
2516         if (ret)
2517                 dev_err(&ctlr->dev, "queue restart failed\n");
2518
2519         return ret;
2520 }
2521 EXPORT_SYMBOL_GPL(spi_controller_resume);
2522
2523 static int __spi_controller_match(struct device *dev, const void *data)
2524 {
2525         struct spi_controller *ctlr;
2526         const u16 *bus_num = data;
2527
2528         ctlr = container_of(dev, struct spi_controller, dev);
2529         return ctlr->bus_num == *bus_num;
2530 }
2531
2532 /**
2533  * spi_busnum_to_master - look up master associated with bus_num
2534  * @bus_num: the master's bus number
2535  * Context: can sleep
2536  *
2537  * This call may be used with devices that are registered after
2538  * arch init time.  It returns a refcounted pointer to the relevant
2539  * spi_controller (which the caller must release), or NULL if there is
2540  * no such master registered.
2541  *
2542  * Return: the SPI master structure on success, else NULL.
2543  */
2544 struct spi_controller *spi_busnum_to_master(u16 bus_num)
2545 {
2546         struct device           *dev;
2547         struct spi_controller   *ctlr = NULL;
2548
2549         dev = class_find_device(&spi_master_class, NULL, &bus_num,
2550                                 __spi_controller_match);
2551         if (dev)
2552                 ctlr = container_of(dev, struct spi_controller, dev);
2553         /* reference got in class_find_device */
2554         return ctlr;
2555 }
2556 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
2557
2558 /*-------------------------------------------------------------------------*/
2559
2560 /* Core methods for SPI resource management */
2561
2562 /**
2563  * spi_res_alloc - allocate a spi resource that is life-cycle managed
2564  *                 during the processing of a spi_message while using
2565  *                 spi_transfer_one
2566  * @spi:     the spi device for which we allocate memory
2567  * @release: the release code to execute for this resource
2568  * @size:    size to alloc and return
2569  * @gfp:     GFP allocation flags
2570  *
2571  * Return: the pointer to the allocated data
2572  *
2573  * This may get enhanced in the future to allocate from a memory pool
2574  * of the @spi_device or @spi_controller to avoid repeated allocations.
2575  */
2576 void *spi_res_alloc(struct spi_device *spi,
2577                     spi_res_release_t release,
2578                     size_t size, gfp_t gfp)
2579 {
2580         struct spi_res *sres;
2581
2582         sres = kzalloc(sizeof(*sres) + size, gfp);
2583         if (!sres)
2584                 return NULL;
2585
2586         INIT_LIST_HEAD(&sres->entry);
2587         sres->release = release;
2588
2589         return sres->data;
2590 }
2591 EXPORT_SYMBOL_GPL(spi_res_alloc);
2592
2593 /**
2594  * spi_res_free - free an spi resource
2595  * @res: pointer to the custom data of a resource
2596  *
2597  */
2598 void spi_res_free(void *res)
2599 {
2600         struct spi_res *sres = container_of(res, struct spi_res, data);
2601
2602         if (!res)
2603                 return;
2604
2605         WARN_ON(!list_empty(&sres->entry));
2606         kfree(sres);
2607 }
2608 EXPORT_SYMBOL_GPL(spi_res_free);
2609
2610 /**
2611  * spi_res_add - add a spi_res to the spi_message
2612  * @message: the spi message
2613  * @res:     the spi_resource
2614  */
2615 void spi_res_add(struct spi_message *message, void *res)
2616 {
2617         struct spi_res *sres = container_of(res, struct spi_res, data);
2618
2619         WARN_ON(!list_empty(&sres->entry));
2620         list_add_tail(&sres->entry, &message->resources);
2621 }
2622 EXPORT_SYMBOL_GPL(spi_res_add);
2623
2624 /**
2625  * spi_res_release - release all spi resources for this message
2626  * @ctlr:  the @spi_controller
2627  * @message: the @spi_message
2628  */
2629 void spi_res_release(struct spi_controller *ctlr, struct spi_message *message)
2630 {
2631         struct spi_res *res;
2632
2633         while (!list_empty(&message->resources)) {
2634                 res = list_last_entry(&message->resources,
2635                                       struct spi_res, entry);
2636
2637                 if (res->release)
2638                         res->release(ctlr, message, res->data);
2639
2640                 list_del(&res->entry);
2641
2642                 kfree(res);
2643         }
2644 }
2645 EXPORT_SYMBOL_GPL(spi_res_release);
2646
2647 /*-------------------------------------------------------------------------*/
2648
2649 /* Core methods for spi_message alterations */
2650
2651 static void __spi_replace_transfers_release(struct spi_controller *ctlr,
2652                                             struct spi_message *msg,
2653                                             void *res)
2654 {
2655         struct spi_replaced_transfers *rxfer = res;
2656         size_t i;
2657
2658         /* call extra callback if requested */
2659         if (rxfer->release)
2660                 rxfer->release(ctlr, msg, res);
2661
2662         /* insert replaced transfers back into the message */
2663         list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
2664
2665         /* remove the formerly inserted entries */
2666         for (i = 0; i < rxfer->inserted; i++)
2667                 list_del(&rxfer->inserted_transfers[i].transfer_list);
2668 }
2669
2670 /**
2671  * spi_replace_transfers - replace transfers with several transfers
2672  *                         and register change with spi_message.resources
2673  * @msg:           the spi_message we work upon
2674  * @xfer_first:    the first spi_transfer we want to replace
2675  * @remove:        number of transfers to remove
2676  * @insert:        the number of transfers we want to insert instead
2677  * @release:       extra release code necessary in some circumstances
2678  * @extradatasize: extra data to allocate (with alignment guarantees
2679  *                 of struct @spi_transfer)
2680  * @gfp:           gfp flags
2681  *
2682  * Returns: pointer to @spi_replaced_transfers,
2683  *          PTR_ERR(...) in case of errors.
2684  */
2685 struct spi_replaced_transfers *spi_replace_transfers(
2686         struct spi_message *msg,
2687         struct spi_transfer *xfer_first,
2688         size_t remove,
2689         size_t insert,
2690         spi_replaced_release_t release,
2691         size_t extradatasize,
2692         gfp_t gfp)
2693 {
2694         struct spi_replaced_transfers *rxfer;
2695         struct spi_transfer *xfer;
2696         size_t i;
2697
2698         /* allocate the structure using spi_res */
2699         rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
2700                               insert * sizeof(struct spi_transfer)
2701                               + sizeof(struct spi_replaced_transfers)
2702                               + extradatasize,
2703                               gfp);
2704         if (!rxfer)
2705                 return ERR_PTR(-ENOMEM);
2706
2707         /* the release code to invoke before running the generic release */
2708         rxfer->release = release;
2709
2710         /* assign extradata */
2711         if (extradatasize)
2712                 rxfer->extradata =
2713                         &rxfer->inserted_transfers[insert];
2714
2715         /* init the replaced_transfers list */
2716         INIT_LIST_HEAD(&rxfer->replaced_transfers);
2717
2718         /* assign the list_entry after which we should reinsert
2719          * the @replaced_transfers - it may be spi_message.messages!
2720          */
2721         rxfer->replaced_after = xfer_first->transfer_list.prev;
2722
2723         /* remove the requested number of transfers */
2724         for (i = 0; i < remove; i++) {
2725                 /* if the entry after replaced_after it is msg->transfers
2726                  * then we have been requested to remove more transfers
2727                  * than are in the list
2728                  */
2729                 if (rxfer->replaced_after->next == &msg->transfers) {
2730                         dev_err(&msg->spi->dev,
2731                                 "requested to remove more spi_transfers than are available\n");
2732                         /* insert replaced transfers back into the message */
2733                         list_splice(&rxfer->replaced_transfers,
2734                                     rxfer->replaced_after);
2735
2736                         /* free the spi_replace_transfer structure */
2737                         spi_res_free(rxfer);
2738
2739                         /* and return with an error */
2740                         return ERR_PTR(-EINVAL);
2741                 }
2742
2743                 /* remove the entry after replaced_after from list of
2744                  * transfers and add it to list of replaced_transfers
2745                  */
2746                 list_move_tail(rxfer->replaced_after->next,
2747                                &rxfer->replaced_transfers);
2748         }
2749
2750         /* create copy of the given xfer with identical settings
2751          * based on the first transfer to get removed
2752          */
2753         for (i = 0; i < insert; i++) {
2754                 /* we need to run in reverse order */
2755                 xfer = &rxfer->inserted_transfers[insert - 1 - i];
2756
2757                 /* copy all spi_transfer data */
2758                 memcpy(xfer, xfer_first, sizeof(*xfer));
2759
2760                 /* add to list */
2761                 list_add(&xfer->transfer_list, rxfer->replaced_after);
2762
2763                 /* clear cs_change and delay_usecs for all but the last */
2764                 if (i) {
2765                         xfer->cs_change = false;
2766                         xfer->delay_usecs = 0;
2767                 }
2768         }
2769
2770         /* set up inserted */
2771         rxfer->inserted = insert;
2772
2773         /* and register it with spi_res/spi_message */
2774         spi_res_add(msg, rxfer);
2775
2776         return rxfer;
2777 }
2778 EXPORT_SYMBOL_GPL(spi_replace_transfers);
2779
2780 static int __spi_split_transfer_maxsize(struct spi_controller *ctlr,
2781                                         struct spi_message *msg,
2782                                         struct spi_transfer **xferp,
2783                                         size_t maxsize,
2784                                         gfp_t gfp)
2785 {
2786         struct spi_transfer *xfer = *xferp, *xfers;
2787         struct spi_replaced_transfers *srt;
2788         size_t offset;
2789         size_t count, i;
2790
2791         /* calculate how many we have to replace */
2792         count = DIV_ROUND_UP(xfer->len, maxsize);
2793
2794         /* create replacement */
2795         srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
2796         if (IS_ERR(srt))
2797                 return PTR_ERR(srt);
2798         xfers = srt->inserted_transfers;
2799
2800         /* now handle each of those newly inserted spi_transfers
2801          * note that the replacements spi_transfers all are preset
2802          * to the same values as *xferp, so tx_buf, rx_buf and len
2803          * are all identical (as well as most others)
2804          * so we just have to fix up len and the pointers.
2805          *
2806          * this also includes support for the depreciated
2807          * spi_message.is_dma_mapped interface
2808          */
2809
2810         /* the first transfer just needs the length modified, so we
2811          * run it outside the loop
2812          */
2813         xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
2814
2815         /* all the others need rx_buf/tx_buf also set */
2816         for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
2817                 /* update rx_buf, tx_buf and dma */
2818                 if (xfers[i].rx_buf)
2819                         xfers[i].rx_buf += offset;
2820                 if (xfers[i].rx_dma)
2821                         xfers[i].rx_dma += offset;
2822                 if (xfers[i].tx_buf)
2823                         xfers[i].tx_buf += offset;
2824                 if (xfers[i].tx_dma)
2825                         xfers[i].tx_dma += offset;
2826
2827                 /* update length */
2828                 xfers[i].len = min(maxsize, xfers[i].len - offset);
2829         }
2830
2831         /* we set up xferp to the last entry we have inserted,
2832          * so that we skip those already split transfers
2833          */
2834         *xferp = &xfers[count - 1];
2835
2836         /* increment statistics counters */
2837         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
2838                                        transfers_split_maxsize);
2839         SPI_STATISTICS_INCREMENT_FIELD(&msg->spi->statistics,
2840                                        transfers_split_maxsize);
2841
2842         return 0;
2843 }
2844
2845 /**
2846  * spi_split_tranfers_maxsize - split spi transfers into multiple transfers
2847  *                              when an individual transfer exceeds a
2848  *                              certain size
2849  * @ctlr:    the @spi_controller for this transfer
2850  * @msg:   the @spi_message to transform
2851  * @maxsize:  the maximum when to apply this
2852  * @gfp: GFP allocation flags
2853  *
2854  * Return: status of transformation
2855  */
2856 int spi_split_transfers_maxsize(struct spi_controller *ctlr,
2857                                 struct spi_message *msg,
2858                                 size_t maxsize,
2859                                 gfp_t gfp)
2860 {
2861         struct spi_transfer *xfer;
2862         int ret;
2863
2864         /* iterate over the transfer_list,
2865          * but note that xfer is advanced to the last transfer inserted
2866          * to avoid checking sizes again unnecessarily (also xfer does
2867          * potentiall belong to a different list by the time the
2868          * replacement has happened
2869          */
2870         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
2871                 if (xfer->len > maxsize) {
2872                         ret = __spi_split_transfer_maxsize(ctlr, msg, &xfer,
2873                                                            maxsize, gfp);
2874                         if (ret)
2875                                 return ret;
2876                 }
2877         }
2878
2879         return 0;
2880 }
2881 EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
2882
2883 /*-------------------------------------------------------------------------*/
2884
2885 /* Core methods for SPI controller protocol drivers.  Some of the
2886  * other core methods are currently defined as inline functions.
2887  */
2888
2889 static int __spi_validate_bits_per_word(struct spi_controller *ctlr,
2890                                         u8 bits_per_word)
2891 {
2892         if (ctlr->bits_per_word_mask) {
2893                 /* Only 32 bits fit in the mask */
2894                 if (bits_per_word > 32)
2895                         return -EINVAL;
2896                 if (!(ctlr->bits_per_word_mask & SPI_BPW_MASK(bits_per_word)))
2897                         return -EINVAL;
2898         }
2899
2900         return 0;
2901 }
2902
2903 /**
2904  * spi_setup - setup SPI mode and clock rate
2905  * @spi: the device whose settings are being modified
2906  * Context: can sleep, and no requests are queued to the device
2907  *
2908  * SPI protocol drivers may need to update the transfer mode if the
2909  * device doesn't work with its default.  They may likewise need
2910  * to update clock rates or word sizes from initial values.  This function
2911  * changes those settings, and must be called from a context that can sleep.
2912  * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
2913  * effect the next time the device is selected and data is transferred to
2914  * or from it.  When this function returns, the spi device is deselected.
2915  *
2916  * Note that this call will fail if the protocol driver specifies an option
2917  * that the underlying controller or its driver does not support.  For
2918  * example, not all hardware supports wire transfers using nine bit words,
2919  * LSB-first wire encoding, or active-high chipselects.
2920  *
2921  * Return: zero on success, else a negative error code.
2922  */
2923 int spi_setup(struct spi_device *spi)
2924 {
2925         unsigned        bad_bits, ugly_bits;
2926         int             status;
2927
2928         /* check mode to prevent that DUAL and QUAD set at the same time
2929          */
2930         if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
2931                 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
2932                 dev_err(&spi->dev,
2933                 "setup: can not select dual and quad at the same time\n");
2934                 return -EINVAL;
2935         }
2936         /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
2937          */
2938         if ((spi->mode & SPI_3WIRE) && (spi->mode &
2939                 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
2940                  SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL)))
2941                 return -EINVAL;
2942         /* help drivers fail *cleanly* when they need options
2943          * that aren't supported with their current controller
2944          * SPI_CS_WORD has a fallback software implementation,
2945          * so it is ignored here.
2946          */
2947         bad_bits = spi->mode & ~(spi->controller->mode_bits | SPI_CS_WORD);
2948         /* nothing prevents from working with active-high CS in case if it
2949          * is driven by GPIO.
2950          */
2951         if (gpio_is_valid(spi->cs_gpio))
2952                 bad_bits &= ~SPI_CS_HIGH;
2953         ugly_bits = bad_bits &
2954                     (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
2955                      SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL);
2956         if (ugly_bits) {
2957                 dev_warn(&spi->dev,
2958                          "setup: ignoring unsupported mode bits %x\n",
2959                          ugly_bits);
2960                 spi->mode &= ~ugly_bits;
2961                 bad_bits &= ~ugly_bits;
2962         }
2963         if (bad_bits) {
2964                 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
2965                         bad_bits);
2966                 return -EINVAL;
2967         }
2968
2969         if (!spi->bits_per_word)
2970                 spi->bits_per_word = 8;
2971
2972         status = __spi_validate_bits_per_word(spi->controller,
2973                                               spi->bits_per_word);
2974         if (status)
2975                 return status;
2976
2977         if (!spi->max_speed_hz)
2978                 spi->max_speed_hz = spi->controller->max_speed_hz;
2979
2980         if (spi->controller->setup)
2981                 status = spi->controller->setup(spi);
2982
2983         spi_set_cs(spi, false);
2984
2985         dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
2986                         (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
2987                         (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
2988                         (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
2989                         (spi->mode & SPI_3WIRE) ? "3wire, " : "",
2990                         (spi->mode & SPI_LOOP) ? "loopback, " : "",
2991                         spi->bits_per_word, spi->max_speed_hz,
2992                         status);
2993
2994         return status;
2995 }
2996 EXPORT_SYMBOL_GPL(spi_setup);
2997
2998 /**
2999  * spi_set_cs_timing - configure CS setup, hold, and inactive delays
3000  * @spi: the device that requires specific CS timing configuration
3001  * @setup: CS setup time in terms of clock count
3002  * @hold: CS hold time in terms of clock count
3003  * @inactive_dly: CS inactive delay between transfers in terms of clock count
3004  */
3005 void spi_set_cs_timing(struct spi_device *spi, u8 setup, u8 hold,
3006                        u8 inactive_dly)
3007 {
3008         if (spi->controller->set_cs_timing)
3009                 spi->controller->set_cs_timing(spi, setup, hold, inactive_dly);
3010 }
3011 EXPORT_SYMBOL_GPL(spi_set_cs_timing);
3012
3013 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
3014 {
3015         struct spi_controller *ctlr = spi->controller;
3016         struct spi_transfer *xfer;
3017         int w_size;
3018
3019         if (list_empty(&message->transfers))
3020                 return -EINVAL;
3021
3022         /* If an SPI controller does not support toggling the CS line on each
3023          * transfer (indicated by the SPI_CS_WORD flag) or we are using a GPIO
3024          * for the CS line, we can emulate the CS-per-word hardware function by
3025          * splitting transfers into one-word transfers and ensuring that
3026          * cs_change is set for each transfer.
3027          */
3028         if ((spi->mode & SPI_CS_WORD) && (!(ctlr->mode_bits & SPI_CS_WORD) ||
3029                                           spi->cs_gpiod ||
3030                                           gpio_is_valid(spi->cs_gpio))) {
3031                 size_t maxsize;
3032                 int ret;
3033
3034                 maxsize = (spi->bits_per_word + 7) / 8;
3035
3036                 /* spi_split_transfers_maxsize() requires message->spi */
3037                 message->spi = spi;
3038
3039                 ret = spi_split_transfers_maxsize(ctlr, message, maxsize,
3040                                                   GFP_KERNEL);
3041                 if (ret)
3042                         return ret;
3043
3044                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3045                         /* don't change cs_change on the last entry in the list */
3046                         if (list_is_last(&xfer->transfer_list, &message->transfers))
3047                                 break;
3048                         xfer->cs_change = 1;
3049                 }
3050         }
3051
3052         /* Half-duplex links include original MicroWire, and ones with
3053          * only one data pin like SPI_3WIRE (switches direction) or where
3054          * either MOSI or MISO is missing.  They can also be caused by
3055          * software limitations.
3056          */
3057         if ((ctlr->flags & SPI_CONTROLLER_HALF_DUPLEX) ||
3058             (spi->mode & SPI_3WIRE)) {
3059                 unsigned flags = ctlr->flags;
3060
3061                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3062                         if (xfer->rx_buf && xfer->tx_buf)
3063                                 return -EINVAL;
3064                         if ((flags & SPI_CONTROLLER_NO_TX) && xfer->tx_buf)
3065                                 return -EINVAL;
3066                         if ((flags & SPI_CONTROLLER_NO_RX) && xfer->rx_buf)
3067                                 return -EINVAL;
3068                 }
3069         }
3070
3071         /**
3072          * Set transfer bits_per_word and max speed as spi device default if
3073          * it is not set for this transfer.
3074          * Set transfer tx_nbits and rx_nbits as single transfer default
3075          * (SPI_NBITS_SINGLE) if it is not set for this transfer.
3076          * Ensure transfer word_delay is at least as long as that required by
3077          * device itself.
3078          */
3079         message->frame_length = 0;
3080         list_for_each_entry(xfer, &message->transfers, transfer_list) {
3081                 message->frame_length += xfer->len;
3082                 if (!xfer->bits_per_word)
3083                         xfer->bits_per_word = spi->bits_per_word;
3084
3085                 if (!xfer->speed_hz)
3086                         xfer->speed_hz = spi->max_speed_hz;
3087
3088                 if (ctlr->max_speed_hz && xfer->speed_hz > ctlr->max_speed_hz)
3089                         xfer->speed_hz = ctlr->max_speed_hz;
3090
3091                 if (__spi_validate_bits_per_word(ctlr, xfer->bits_per_word))
3092                         return -EINVAL;
3093
3094                 /*
3095                  * SPI transfer length should be multiple of SPI word size
3096                  * where SPI word size should be power-of-two multiple
3097                  */
3098                 if (xfer->bits_per_word <= 8)
3099                         w_size = 1;
3100                 else if (xfer->bits_per_word <= 16)
3101                         w_size = 2;
3102                 else
3103                         w_size = 4;
3104
3105                 /* No partial transfers accepted */
3106                 if (xfer->len % w_size)
3107                         return -EINVAL;
3108
3109                 if (xfer->speed_hz && ctlr->min_speed_hz &&
3110                     xfer->speed_hz < ctlr->min_speed_hz)
3111                         return -EINVAL;
3112
3113                 if (xfer->tx_buf && !xfer->tx_nbits)
3114                         xfer->tx_nbits = SPI_NBITS_SINGLE;
3115                 if (xfer->rx_buf && !xfer->rx_nbits)
3116                         xfer->rx_nbits = SPI_NBITS_SINGLE;
3117                 /* check transfer tx/rx_nbits:
3118                  * 1. check the value matches one of single, dual and quad
3119                  * 2. check tx/rx_nbits match the mode in spi_device
3120                  */
3121                 if (xfer->tx_buf) {
3122                         if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
3123                                 xfer->tx_nbits != SPI_NBITS_DUAL &&
3124                                 xfer->tx_nbits != SPI_NBITS_QUAD)
3125                                 return -EINVAL;
3126                         if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
3127                                 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
3128                                 return -EINVAL;
3129                         if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
3130                                 !(spi->mode & SPI_TX_QUAD))
3131                                 return -EINVAL;
3132                 }
3133                 /* check transfer rx_nbits */
3134                 if (xfer->rx_buf) {
3135                         if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
3136                                 xfer->rx_nbits != SPI_NBITS_DUAL &&
3137                                 xfer->rx_nbits != SPI_NBITS_QUAD)
3138                                 return -EINVAL;
3139                         if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
3140                                 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
3141                                 return -EINVAL;
3142                         if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
3143                                 !(spi->mode & SPI_RX_QUAD))
3144                                 return -EINVAL;
3145                 }
3146
3147                 if (xfer->word_delay_usecs < spi->word_delay_usecs)
3148                         xfer->word_delay_usecs = spi->word_delay_usecs;
3149         }
3150
3151         message->status = -EINPROGRESS;
3152
3153         return 0;
3154 }
3155
3156 static int __spi_async(struct spi_device *spi, struct spi_message *message)
3157 {
3158         struct spi_controller *ctlr = spi->controller;
3159
3160         /*
3161          * Some controllers do not support doing regular SPI transfers. Return
3162          * ENOTSUPP when this is the case.
3163          */
3164         if (!ctlr->transfer)
3165                 return -ENOTSUPP;
3166
3167         message->spi = spi;
3168
3169         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_async);
3170         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
3171
3172         trace_spi_message_submit(message);
3173
3174         return ctlr->transfer(spi, message);
3175 }
3176
3177 /**
3178  * spi_async - asynchronous SPI transfer
3179  * @spi: device with which data will be exchanged
3180  * @message: describes the data transfers, including completion callback
3181  * Context: any (irqs may be blocked, etc)
3182  *
3183  * This call may be used in_irq and other contexts which can't sleep,
3184  * as well as from task contexts which can sleep.
3185  *
3186  * The completion callback is invoked in a context which can't sleep.
3187  * Before that invocation, the value of message->status is undefined.
3188  * When the callback is issued, message->status holds either zero (to
3189  * indicate complete success) or a negative error code.  After that
3190  * callback returns, the driver which issued the transfer request may
3191  * deallocate the associated memory; it's no longer in use by any SPI
3192  * core or controller driver code.
3193  *
3194  * Note that although all messages to a spi_device are handled in
3195  * FIFO order, messages may go to different devices in other orders.
3196  * Some device might be higher priority, or have various "hard" access
3197  * time requirements, for example.
3198  *
3199  * On detection of any fault during the transfer, processing of
3200  * the entire message is aborted, and the device is deselected.
3201  * Until returning from the associated message completion callback,
3202  * no other spi_message queued to that device will be processed.
3203  * (This rule applies equally to all the synchronous transfer calls,
3204  * which are wrappers around this core asynchronous primitive.)
3205  *
3206  * Return: zero on success, else a negative error code.
3207  */
3208 int spi_async(struct spi_device *spi, struct spi_message *message)
3209 {
3210         struct spi_controller *ctlr = spi->controller;
3211         int ret;
3212         unsigned long flags;
3213
3214         ret = __spi_validate(spi, message);
3215         if (ret != 0)
3216                 return ret;
3217
3218         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3219
3220         if (ctlr->bus_lock_flag)
3221                 ret = -EBUSY;
3222         else
3223                 ret = __spi_async(spi, message);
3224
3225         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3226
3227         return ret;
3228 }
3229 EXPORT_SYMBOL_GPL(spi_async);
3230
3231 /**
3232  * spi_async_locked - version of spi_async with exclusive bus usage
3233  * @spi: device with which data will be exchanged
3234  * @message: describes the data transfers, including completion callback
3235  * Context: any (irqs may be blocked, etc)
3236  *
3237  * This call may be used in_irq and other contexts which can't sleep,
3238  * as well as from task contexts which can sleep.
3239  *
3240  * The completion callback is invoked in a context which can't sleep.
3241  * Before that invocation, the value of message->status is undefined.
3242  * When the callback is issued, message->status holds either zero (to
3243  * indicate complete success) or a negative error code.  After that
3244  * callback returns, the driver which issued the transfer request may
3245  * deallocate the associated memory; it's no longer in use by any SPI
3246  * core or controller driver code.
3247  *
3248  * Note that although all messages to a spi_device are handled in
3249  * FIFO order, messages may go to different devices in other orders.
3250  * Some device might be higher priority, or have various "hard" access
3251  * time requirements, for example.
3252  *
3253  * On detection of any fault during the transfer, processing of
3254  * the entire message is aborted, and the device is deselected.
3255  * Until returning from the associated message completion callback,
3256  * no other spi_message queued to that device will be processed.
3257  * (This rule applies equally to all the synchronous transfer calls,
3258  * which are wrappers around this core asynchronous primitive.)
3259  *
3260  * Return: zero on success, else a negative error code.
3261  */
3262 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
3263 {
3264         struct spi_controller *ctlr = spi->controller;
3265         int ret;
3266         unsigned long flags;
3267
3268         ret = __spi_validate(spi, message);
3269         if (ret != 0)
3270                 return ret;
3271
3272         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3273
3274         ret = __spi_async(spi, message);
3275
3276         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3277
3278         return ret;
3279
3280 }
3281 EXPORT_SYMBOL_GPL(spi_async_locked);
3282
3283 /*-------------------------------------------------------------------------*/
3284
3285 /* Utility methods for SPI protocol drivers, layered on
3286  * top of the core.  Some other utility methods are defined as
3287  * inline functions.
3288  */
3289
3290 static void spi_complete(void *arg)
3291 {
3292         complete(arg);
3293 }
3294
3295 static int __spi_sync(struct spi_device *spi, struct spi_message *message)
3296 {
3297         DECLARE_COMPLETION_ONSTACK(done);
3298         int status;
3299         struct spi_controller *ctlr = spi->controller;
3300         unsigned long flags;
3301
3302         status = __spi_validate(spi, message);
3303         if (status != 0)
3304                 return status;
3305
3306         message->complete = spi_complete;
3307         message->context = &done;
3308         message->spi = spi;
3309
3310         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_sync);
3311         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
3312
3313         /* If we're not using the legacy transfer method then we will
3314          * try to transfer in the calling context so special case.
3315          * This code would be less tricky if we could remove the
3316          * support for driver implemented message queues.
3317          */
3318         if (ctlr->transfer == spi_queued_transfer) {
3319                 spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3320
3321                 trace_spi_message_submit(message);
3322
3323                 status = __spi_queued_transfer(spi, message, false);
3324
3325                 spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3326         } else {
3327                 status = spi_async_locked(spi, message);
3328         }
3329
3330         if (status == 0) {
3331                 /* Push out the messages in the calling context if we
3332                  * can.
3333                  */
3334                 if (ctlr->transfer == spi_queued_transfer) {
3335                         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
3336                                                        spi_sync_immediate);
3337                         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
3338                                                        spi_sync_immediate);
3339                         __spi_pump_messages(ctlr, false);
3340                 }
3341
3342                 wait_for_completion(&done);
3343                 status = message->status;
3344         }
3345         message->context = NULL;
3346         return status;
3347 }
3348
3349 /**
3350  * spi_sync - blocking/synchronous SPI data transfers
3351  * @spi: device with which data will be exchanged
3352  * @message: describes the data transfers
3353  * Context: can sleep
3354  *
3355  * This call may only be used from a context that may sleep.  The sleep
3356  * is non-interruptible, and has no timeout.  Low-overhead controller
3357  * drivers may DMA directly into and out of the message buffers.
3358  *
3359  * Note that the SPI device's chip select is active during the message,
3360  * and then is normally disabled between messages.  Drivers for some
3361  * frequently-used devices may want to minimize costs of selecting a chip,
3362  * by leaving it selected in anticipation that the next message will go
3363  * to the same chip.  (That may increase power usage.)
3364  *
3365  * Also, the caller is guaranteeing that the memory associated with the
3366  * message will not be freed before this call returns.
3367  *
3368  * Return: zero on success, else a negative error code.
3369  */
3370 int spi_sync(struct spi_device *spi, struct spi_message *message)
3371 {
3372         int ret;
3373
3374         mutex_lock(&spi->controller->bus_lock_mutex);
3375         ret = __spi_sync(spi, message);
3376         mutex_unlock(&spi->controller->bus_lock_mutex);
3377
3378         return ret;
3379 }
3380 EXPORT_SYMBOL_GPL(spi_sync);
3381
3382 /**
3383  * spi_sync_locked - version of spi_sync with exclusive bus usage
3384  * @spi: device with which data will be exchanged
3385  * @message: describes the data transfers
3386  * Context: can sleep
3387  *
3388  * This call may only be used from a context that may sleep.  The sleep
3389  * is non-interruptible, and has no timeout.  Low-overhead controller
3390  * drivers may DMA directly into and out of the message buffers.
3391  *
3392  * This call should be used by drivers that require exclusive access to the
3393  * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
3394  * be released by a spi_bus_unlock call when the exclusive access is over.
3395  *
3396  * Return: zero on success, else a negative error code.
3397  */
3398 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
3399 {
3400         return __spi_sync(spi, message);
3401 }
3402 EXPORT_SYMBOL_GPL(spi_sync_locked);
3403
3404 /**
3405  * spi_bus_lock - obtain a lock for exclusive SPI bus usage
3406  * @ctlr: SPI bus master that should be locked for exclusive bus access
3407  * Context: can sleep
3408  *
3409  * This call may only be used from a context that may sleep.  The sleep
3410  * is non-interruptible, and has no timeout.
3411  *
3412  * This call should be used by drivers that require exclusive access to the
3413  * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
3414  * exclusive access is over. Data transfer must be done by spi_sync_locked
3415  * and spi_async_locked calls when the SPI bus lock is held.
3416  *
3417  * Return: always zero.
3418  */
3419 int spi_bus_lock(struct spi_controller *ctlr)
3420 {
3421         unsigned long flags;
3422
3423         mutex_lock(&ctlr->bus_lock_mutex);
3424
3425         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3426         ctlr->bus_lock_flag = 1;
3427         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3428
3429         /* mutex remains locked until spi_bus_unlock is called */
3430
3431         return 0;
3432 }
3433 EXPORT_SYMBOL_GPL(spi_bus_lock);
3434
3435 /**
3436  * spi_bus_unlock - release the lock for exclusive SPI bus usage
3437  * @ctlr: SPI bus master that was locked for exclusive bus access
3438  * Context: can sleep
3439  *
3440  * This call may only be used from a context that may sleep.  The sleep
3441  * is non-interruptible, and has no timeout.
3442  *
3443  * This call releases an SPI bus lock previously obtained by an spi_bus_lock
3444  * call.
3445  *
3446  * Return: always zero.
3447  */
3448 int spi_bus_unlock(struct spi_controller *ctlr)
3449 {
3450         ctlr->bus_lock_flag = 0;
3451
3452         mutex_unlock(&ctlr->bus_lock_mutex);
3453
3454         return 0;
3455 }
3456 EXPORT_SYMBOL_GPL(spi_bus_unlock);
3457
3458 /* portable code must never pass more than 32 bytes */
3459 #define SPI_BUFSIZ      max(32, SMP_CACHE_BYTES)
3460
3461 static u8       *buf;
3462
3463 /**
3464  * spi_write_then_read - SPI synchronous write followed by read
3465  * @spi: device with which data will be exchanged
3466  * @txbuf: data to be written (need not be dma-safe)
3467  * @n_tx: size of txbuf, in bytes
3468  * @rxbuf: buffer into which data will be read (need not be dma-safe)
3469  * @n_rx: size of rxbuf, in bytes
3470  * Context: can sleep
3471  *
3472  * This performs a half duplex MicroWire style transaction with the
3473  * device, sending txbuf and then reading rxbuf.  The return value
3474  * is zero for success, else a negative errno status code.
3475  * This call may only be used from a context that may sleep.
3476  *
3477  * Parameters to this routine are always copied using a small buffer;
3478  * portable code should never use this for more than 32 bytes.
3479  * Performance-sensitive or bulk transfer code should instead use
3480  * spi_{async,sync}() calls with dma-safe buffers.
3481  *
3482  * Return: zero on success, else a negative error code.
3483  */
3484 int spi_write_then_read(struct spi_device *spi,
3485                 const void *txbuf, unsigned n_tx,
3486                 void *rxbuf, unsigned n_rx)
3487 {
3488         static DEFINE_MUTEX(lock);
3489
3490         int                     status;
3491         struct spi_message      message;
3492         struct spi_transfer     x[2];
3493         u8                      *local_buf;
3494
3495         /* Use preallocated DMA-safe buffer if we can.  We can't avoid
3496          * copying here, (as a pure convenience thing), but we can
3497          * keep heap costs out of the hot path unless someone else is
3498          * using the pre-allocated buffer or the transfer is too large.
3499          */
3500         if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
3501                 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
3502                                     GFP_KERNEL | GFP_DMA);
3503                 if (!local_buf)
3504                         return -ENOMEM;
3505         } else {
3506                 local_buf = buf;
3507         }
3508
3509         spi_message_init(&message);
3510         memset(x, 0, sizeof(x));
3511         if (n_tx) {
3512                 x[0].len = n_tx;
3513                 spi_message_add_tail(&x[0], &message);
3514         }
3515         if (n_rx) {
3516                 x[1].len = n_rx;
3517                 spi_message_add_tail(&x[1], &message);
3518         }
3519
3520         memcpy(local_buf, txbuf, n_tx);
3521         x[0].tx_buf = local_buf;
3522         x[1].rx_buf = local_buf + n_tx;
3523
3524         /* do the i/o */
3525         status = spi_sync(spi, &message);
3526         if (status == 0)
3527                 memcpy(rxbuf, x[1].rx_buf, n_rx);
3528
3529         if (x[0].tx_buf == buf)
3530                 mutex_unlock(&lock);
3531         else
3532                 kfree(local_buf);
3533
3534         return status;
3535 }
3536 EXPORT_SYMBOL_GPL(spi_write_then_read);
3537
3538 /*-------------------------------------------------------------------------*/
3539
3540 #if IS_ENABLED(CONFIG_OF)
3541 static int __spi_of_device_match(struct device *dev, void *data)
3542 {
3543         return dev->of_node == data;
3544 }
3545
3546 /* must call put_device() when done with returned spi_device device */
3547 struct spi_device *of_find_spi_device_by_node(struct device_node *node)
3548 {
3549         struct device *dev = bus_find_device(&spi_bus_type, NULL, node,
3550                                                 __spi_of_device_match);
3551         return dev ? to_spi_device(dev) : NULL;
3552 }
3553 EXPORT_SYMBOL_GPL(of_find_spi_device_by_node);
3554 #endif /* IS_ENABLED(CONFIG_OF) */
3555
3556 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
3557 static int __spi_of_controller_match(struct device *dev, const void *data)
3558 {
3559         return dev->of_node == data;
3560 }
3561
3562 /* the spi controllers are not using spi_bus, so we find it with another way */
3563 static struct spi_controller *of_find_spi_controller_by_node(struct device_node *node)
3564 {
3565         struct device *dev;
3566
3567         dev = class_find_device(&spi_master_class, NULL, node,
3568                                 __spi_of_controller_match);
3569         if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
3570                 dev = class_find_device(&spi_slave_class, NULL, node,
3571                                         __spi_of_controller_match);
3572         if (!dev)
3573                 return NULL;
3574
3575         /* reference got in class_find_device */
3576         return container_of(dev, struct spi_controller, dev);
3577 }
3578
3579 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
3580                          void *arg)
3581 {
3582         struct of_reconfig_data *rd = arg;
3583         struct spi_controller *ctlr;
3584         struct spi_device *spi;
3585
3586         switch (of_reconfig_get_state_change(action, arg)) {
3587         case OF_RECONFIG_CHANGE_ADD:
3588                 ctlr = of_find_spi_controller_by_node(rd->dn->parent);
3589                 if (ctlr == NULL)
3590                         return NOTIFY_OK;       /* not for us */
3591
3592                 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
3593                         put_device(&ctlr->dev);
3594                         return NOTIFY_OK;
3595                 }
3596
3597                 spi = of_register_spi_device(ctlr, rd->dn);
3598                 put_device(&ctlr->dev);
3599
3600                 if (IS_ERR(spi)) {
3601                         pr_err("%s: failed to create for '%pOF'\n",
3602                                         __func__, rd->dn);
3603                         of_node_clear_flag(rd->dn, OF_POPULATED);
3604                         return notifier_from_errno(PTR_ERR(spi));
3605                 }
3606                 break;
3607
3608         case OF_RECONFIG_CHANGE_REMOVE:
3609                 /* already depopulated? */
3610                 if (!of_node_check_flag(rd->dn, OF_POPULATED))
3611                         return NOTIFY_OK;
3612
3613                 /* find our device by node */
3614                 spi = of_find_spi_device_by_node(rd->dn);
3615                 if (spi == NULL)
3616                         return NOTIFY_OK;       /* no? not meant for us */
3617
3618                 /* unregister takes one ref away */
3619                 spi_unregister_device(spi);
3620
3621                 /* and put the reference of the find */
3622                 put_device(&spi->dev);
3623                 break;
3624         }
3625
3626         return NOTIFY_OK;
3627 }
3628
3629 static struct notifier_block spi_of_notifier = {
3630         .notifier_call = of_spi_notify,
3631 };
3632 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3633 extern struct notifier_block spi_of_notifier;
3634 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3635
3636 #if IS_ENABLED(CONFIG_ACPI)
3637 static int spi_acpi_controller_match(struct device *dev, const void *data)
3638 {
3639         return ACPI_COMPANION(dev->parent) == data;
3640 }
3641
3642 static int spi_acpi_device_match(struct device *dev, void *data)
3643 {
3644         return ACPI_COMPANION(dev) == data;
3645 }
3646
3647 static struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev)
3648 {
3649         struct device *dev;
3650
3651         dev = class_find_device(&spi_master_class, NULL, adev,
3652                                 spi_acpi_controller_match);
3653         if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
3654                 dev = class_find_device(&spi_slave_class, NULL, adev,
3655                                         spi_acpi_controller_match);
3656         if (!dev)
3657                 return NULL;
3658
3659         return container_of(dev, struct spi_controller, dev);
3660 }
3661
3662 static struct spi_device *acpi_spi_find_device_by_adev(struct acpi_device *adev)
3663 {
3664         struct device *dev;
3665
3666         dev = bus_find_device(&spi_bus_type, NULL, adev, spi_acpi_device_match);
3667
3668         return dev ? to_spi_device(dev) : NULL;
3669 }
3670
3671 static int acpi_spi_notify(struct notifier_block *nb, unsigned long value,
3672                            void *arg)
3673 {
3674         struct acpi_device *adev = arg;
3675         struct spi_controller *ctlr;
3676         struct spi_device *spi;
3677
3678         switch (value) {
3679         case ACPI_RECONFIG_DEVICE_ADD:
3680                 ctlr = acpi_spi_find_controller_by_adev(adev->parent);
3681                 if (!ctlr)
3682                         break;
3683
3684                 acpi_register_spi_device(ctlr, adev);
3685                 put_device(&ctlr->dev);
3686                 break;
3687         case ACPI_RECONFIG_DEVICE_REMOVE:
3688                 if (!acpi_device_enumerated(adev))
3689                         break;
3690
3691                 spi = acpi_spi_find_device_by_adev(adev);
3692                 if (!spi)
3693                         break;
3694
3695                 spi_unregister_device(spi);
3696                 put_device(&spi->dev);
3697                 break;
3698         }
3699
3700         return NOTIFY_OK;
3701 }
3702
3703 static struct notifier_block spi_acpi_notifier = {
3704         .notifier_call = acpi_spi_notify,
3705 };
3706 #else
3707 extern struct notifier_block spi_acpi_notifier;
3708 #endif
3709
3710 static int __init spi_init(void)
3711 {
3712         int     status;
3713
3714         buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
3715         if (!buf) {
3716                 status = -ENOMEM;
3717                 goto err0;
3718         }
3719
3720         status = bus_register(&spi_bus_type);
3721         if (status < 0)
3722                 goto err1;
3723
3724         status = class_register(&spi_master_class);
3725         if (status < 0)
3726                 goto err2;
3727
3728         if (IS_ENABLED(CONFIG_SPI_SLAVE)) {
3729                 status = class_register(&spi_slave_class);
3730                 if (status < 0)
3731                         goto err3;
3732         }
3733
3734         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
3735                 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
3736         if (IS_ENABLED(CONFIG_ACPI))
3737                 WARN_ON(acpi_reconfig_notifier_register(&spi_acpi_notifier));
3738
3739         return 0;
3740
3741 err3:
3742         class_unregister(&spi_master_class);
3743 err2:
3744         bus_unregister(&spi_bus_type);
3745 err1:
3746         kfree(buf);
3747         buf = NULL;
3748 err0:
3749         return status;
3750 }
3751
3752 /* board_info is normally registered in arch_initcall(),
3753  * but even essential drivers wait till later
3754  *
3755  * REVISIT only boardinfo really needs static linking. the rest (device and
3756  * driver registration) _could_ be dynamically linked (modular) ... costs
3757  * include needing to have boardinfo data structures be much more public.
3758  */
3759 postcore_initcall(spi_init);
3760