drivers/spi/spi.c

   1 /*
   2  * SPI init/core code
   3  *
   4  * Copyright (C) 2005 David Brownell
   5  * Copyright (C) 2008 Secret Lab Technologies Ltd.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  */
  17
  18 #include <linux/kernel.h>
  19 #include <linux/device.h>
  20 #include <linux/init.h>
  21 #include <linux/cache.h>
  22 #include <linux/dma-mapping.h>
  23 #include <linux/dmaengine.h>
  24 #include <linux/mutex.h>
  25 #include <linux/of_device.h>
  26 #include <linux/of_irq.h>
  27 #include <linux/clk/clk-conf.h>
  28 #include <linux/slab.h>
  29 #include <linux/mod_devicetable.h>
  30 #include <linux/spi/spi.h>
  31 #include <linux/of_gpio.h>
  32 #include <linux/pm_runtime.h>
  33 #include <linux/pm_domain.h>
  34 #include <linux/export.h>
  35 #include <linux/sched/rt.h>
  36 #include <linux/delay.h>
  37 #include <linux/kthread.h>
  38 #include <linux/ioport.h>
  39 #include <linux/acpi.h>
  40 #include <linux/highmem.h>
  41
  42 #define CREATE_TRACE_POINTS
  43 #include <trace/events/spi.h>
  44
  45 static void spidev_release(struct device *dev)
  46 {
  47         struct spi_device       *spi = to_spi_device(dev);
  48
  49         /* spi masters may cleanup for released devices */
  50         if (spi->master->cleanup)
  51                 spi->master->cleanup(spi);
  52
  53         spi_master_put(spi->master);
  54         kfree(spi);
  55 }
  56
  57 static ssize_t
  58 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
  59 {
  60         const struct spi_device *spi = to_spi_device(dev);
  61         int len;
  62
  63         len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
  64         if (len != -ENODEV)
  65                 return len;
  66
  67         return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
  68 }
  69 static DEVICE_ATTR_RO(modalias);
  70
  71 #define SPI_STATISTICS_ATTRS(field, file)                               \
  72 static ssize_t spi_master_##field##_show(struct device *dev,            \
  73                                          struct device_attribute *attr, \
  74                                          char *buf)                     \
  75 {                                                                       \
  76         struct spi_master *master = container_of(dev,                   \
  77                                                  struct spi_master, dev); \
  78         return spi_statistics_##field##_show(&master->statistics, buf); \
  79 }                                                                       \
  80 static struct device_attribute dev_attr_spi_master_##field = {          \
  81         .attr = { .name = file, .mode = S_IRUGO },                      \
  82         .show = spi_master_##field##_show,                              \
  83 };                                                                      \
  84 static ssize_t spi_device_##field##_show(struct device *dev,            \
  85                                          struct device_attribute *attr, \
  86                                         char *buf)                      \
  87 {                                                                       \
  88         struct spi_device *spi = to_spi_device(dev);                    \
  89         return spi_statistics_##field##_show(&spi->statistics, buf);    \
  90 }                                                                       \
  91 static struct device_attribute dev_attr_spi_device_##field = {          \
  92         .attr = { .name = file, .mode = S_IRUGO },                      \
  93         .show = spi_device_##field##_show,                              \
  94 }
  95
  96 #define SPI_STATISTICS_SHOW_NAME(name, file, field, format_string)      \
  97 static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
  98                                             char *buf)                  \
  99 {                                                                       \
 100         unsigned long flags;                                            \
 101         ssize_t len;                                                    \
 102         spin_lock_irqsave(&stat->lock, flags);                          \
 103         len = sprintf(buf, format_string, stat->field);                 \
 104         spin_unlock_irqrestore(&stat->lock, flags);                     \
 105         return len;                                                     \
 106 }                                                                       \
 107 SPI_STATISTICS_ATTRS(name, file)
 108
 109 #define SPI_STATISTICS_SHOW(field, format_string)                       \
 110         SPI_STATISTICS_SHOW_NAME(field, __stringify(field),             \
 111                                  field, format_string)
 112
 113 SPI_STATISTICS_SHOW(messages, "%lu");
 114 SPI_STATISTICS_SHOW(transfers, "%lu");
 115 SPI_STATISTICS_SHOW(errors, "%lu");
 116 SPI_STATISTICS_SHOW(timedout, "%lu");
 117
 118 SPI_STATISTICS_SHOW(spi_sync, "%lu");
 119 SPI_STATISTICS_SHOW(spi_sync_immediate, "%lu");
 120 SPI_STATISTICS_SHOW(spi_async, "%lu");
 121
 122 SPI_STATISTICS_SHOW(bytes, "%llu");
 123 SPI_STATISTICS_SHOW(bytes_rx, "%llu");
 124 SPI_STATISTICS_SHOW(bytes_tx, "%llu");
 125
 126 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number)              \
 127         SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index,           \
 128                                  "transfer_bytes_histo_" number,        \
 129                                  transfer_bytes_histo[index],  "%lu")
 130 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0,  "0-1");
 131 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1,  "2-3");
 132 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2,  "4-7");
 133 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3,  "8-15");
 134 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4,  "16-31");
 135 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5,  "32-63");
 136 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6,  "64-127");
 137 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7,  "128-255");
 138 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8,  "256-511");
 139 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9,  "512-1023");
 140 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
 141 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
 142 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
 143 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
 144 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
 145 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
 146 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
 147
 148 SPI_STATISTICS_SHOW(transfers_split_maxsize, "%lu");
 149
 150 static struct attribute *spi_dev_attrs[] = {
 151         &dev_attr_modalias.attr,
 152         NULL,
 153 };
 154
 155 static const struct attribute_group spi_dev_group = {
 156         .attrs  = spi_dev_attrs,
 157 };
 158
 159 static struct attribute *spi_device_statistics_attrs[] = {
 160         &dev_attr_spi_device_messages.attr,
 161         &dev_attr_spi_device_transfers.attr,
 162         &dev_attr_spi_device_errors.attr,
 163         &dev_attr_spi_device_timedout.attr,
 164         &dev_attr_spi_device_spi_sync.attr,
 165         &dev_attr_spi_device_spi_sync_immediate.attr,
 166         &dev_attr_spi_device_spi_async.attr,
 167         &dev_attr_spi_device_bytes.attr,
 168         &dev_attr_spi_device_bytes_rx.attr,
 169         &dev_attr_spi_device_bytes_tx.attr,
 170         &dev_attr_spi_device_transfer_bytes_histo0.attr,
 171         &dev_attr_spi_device_transfer_bytes_histo1.attr,
 172         &dev_attr_spi_device_transfer_bytes_histo2.attr,
 173         &dev_attr_spi_device_transfer_bytes_histo3.attr,
 174         &dev_attr_spi_device_transfer_bytes_histo4.attr,
 175         &dev_attr_spi_device_transfer_bytes_histo5.attr,
 176         &dev_attr_spi_device_transfer_bytes_histo6.attr,
 177         &dev_attr_spi_device_transfer_bytes_histo7.attr,
 178         &dev_attr_spi_device_transfer_bytes_histo8.attr,
 179         &dev_attr_spi_device_transfer_bytes_histo9.attr,
 180         &dev_attr_spi_device_transfer_bytes_histo10.attr,
 181         &dev_attr_spi_device_transfer_bytes_histo11.attr,
 182         &dev_attr_spi_device_transfer_bytes_histo12.attr,
 183         &dev_attr_spi_device_transfer_bytes_histo13.attr,
 184         &dev_attr_spi_device_transfer_bytes_histo14.attr,
 185         &dev_attr_spi_device_transfer_bytes_histo15.attr,
 186         &dev_attr_spi_device_transfer_bytes_histo16.attr,
 187         &dev_attr_spi_device_transfers_split_maxsize.attr,
 188         NULL,
 189 };
 190
 191 static const struct attribute_group spi_device_statistics_group = {
 192         .name  = "statistics",
 193         .attrs  = spi_device_statistics_attrs,
 194 };
 195
 196 static const struct attribute_group *spi_dev_groups[] = {
 197         &spi_dev_group,
 198         &spi_device_statistics_group,
 199         NULL,
 200 };
 201
 202 static struct attribute *spi_master_statistics_attrs[] = {
 203         &dev_attr_spi_master_messages.attr,
 204         &dev_attr_spi_master_transfers.attr,
 205         &dev_attr_spi_master_errors.attr,
 206         &dev_attr_spi_master_timedout.attr,
 207         &dev_attr_spi_master_spi_sync.attr,
 208         &dev_attr_spi_master_spi_sync_immediate.attr,
 209         &dev_attr_spi_master_spi_async.attr,
 210         &dev_attr_spi_master_bytes.attr,
 211         &dev_attr_spi_master_bytes_rx.attr,
 212         &dev_attr_spi_master_bytes_tx.attr,
 213         &dev_attr_spi_master_transfer_bytes_histo0.attr,
 214         &dev_attr_spi_master_transfer_bytes_histo1.attr,
 215         &dev_attr_spi_master_transfer_bytes_histo2.attr,
 216         &dev_attr_spi_master_transfer_bytes_histo3.attr,
 217         &dev_attr_spi_master_transfer_bytes_histo4.attr,
 218         &dev_attr_spi_master_transfer_bytes_histo5.attr,
 219         &dev_attr_spi_master_transfer_bytes_histo6.attr,
 220         &dev_attr_spi_master_transfer_bytes_histo7.attr,
 221         &dev_attr_spi_master_transfer_bytes_histo8.attr,
 222         &dev_attr_spi_master_transfer_bytes_histo9.attr,
 223         &dev_attr_spi_master_transfer_bytes_histo10.attr,
 224         &dev_attr_spi_master_transfer_bytes_histo11.attr,
 225         &dev_attr_spi_master_transfer_bytes_histo12.attr,
 226         &dev_attr_spi_master_transfer_bytes_histo13.attr,
 227         &dev_attr_spi_master_transfer_bytes_histo14.attr,
 228         &dev_attr_spi_master_transfer_bytes_histo15.attr,
 229         &dev_attr_spi_master_transfer_bytes_histo16.attr,
 230         &dev_attr_spi_master_transfers_split_maxsize.attr,
 231         NULL,
 232 };
 233
 234 static const struct attribute_group spi_master_statistics_group = {
 235         .name  = "statistics",
 236         .attrs  = spi_master_statistics_attrs,
 237 };
 238
 239 static const struct attribute_group *spi_master_groups[] = {
 240         &spi_master_statistics_group,
 241         NULL,
 242 };
 243
 244 void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
 245                                        struct spi_transfer *xfer,
 246                                        struct spi_master *master)
 247 {
 248         unsigned long flags;
 249         int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
 250
 251         if (l2len < 0)
 252                 l2len = 0;
 253
 254         spin_lock_irqsave(&stats->lock, flags);
 255
 256         stats->transfers++;
 257         stats->transfer_bytes_histo[l2len]++;
 258
 259         stats->bytes += xfer->len;
 260         if ((xfer->tx_buf) &&
 261             (xfer->tx_buf != master->dummy_tx))
 262                 stats->bytes_tx += xfer->len;
 263         if ((xfer->rx_buf) &&
 264             (xfer->rx_buf != master->dummy_rx))
 265                 stats->bytes_rx += xfer->len;
 266
 267         spin_unlock_irqrestore(&stats->lock, flags);
 268 }
 269 EXPORT_SYMBOL_GPL(spi_statistics_add_transfer_stats);
 270
 271 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
 272  * and the sysfs version makes coldplug work too.
 273  */
 274
 275 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
 276                                                 const struct spi_device *sdev)
 277 {
 278         while (id->name[0]) {
 279                 if (!strcmp(sdev->modalias, id->name))
 280                         return id;
 281                 id++;
 282         }
 283         return NULL;
 284 }
 285
 286 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
 287 {
 288         const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
 289
 290         return spi_match_id(sdrv->id_table, sdev);
 291 }
 292 EXPORT_SYMBOL_GPL(spi_get_device_id);
 293
 294 static int spi_match_device(struct device *dev, struct device_driver *drv)
 295 {
 296         const struct spi_device *spi = to_spi_device(dev);
 297         const struct spi_driver *sdrv = to_spi_driver(drv);
 298
 299         /* Attempt an OF style match */
 300         if (of_driver_match_device(dev, drv))
 301                 return 1;
 302
 303         /* Then try ACPI */
 304         if (acpi_driver_match_device(dev, drv))
 305                 return 1;
 306
 307         if (sdrv->id_table)
 308                 return !!spi_match_id(sdrv->id_table, spi);
 309
 310         return strcmp(spi->modalias, drv->name) == 0;
 311 }
 312
 313 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
 314 {
 315         const struct spi_device         *spi = to_spi_device(dev);
 316         int rc;
 317
 318         rc = acpi_device_uevent_modalias(dev, env);
 319         if (rc != -ENODEV)
 320                 return rc;
 321
 322         add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
 323         return 0;
 324 }
 325
 326 struct bus_type spi_bus_type = {
 327         .name           = "spi",
 328         .dev_groups     = spi_dev_groups,
 329         .match          = spi_match_device,
 330         .uevent         = spi_uevent,
 331 };
 332 EXPORT_SYMBOL_GPL(spi_bus_type);
 333
 334
 335 static int spi_drv_probe(struct device *dev)
 336 {
 337         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 338         struct spi_device               *spi = to_spi_device(dev);
 339         int ret;
 340
 341         ret = of_clk_set_defaults(dev->of_node, false);
 342         if (ret)
 343                 return ret;
 344
 345         if (dev->of_node) {
 346                 spi->irq = of_irq_get(dev->of_node, 0);
 347                 if (spi->irq == -EPROBE_DEFER)
 348                         return -EPROBE_DEFER;
 349                 if (spi->irq < 0)
 350                         spi->irq = 0;
 351         }
 352
 353         ret = dev_pm_domain_attach(dev, true);
 354         if (ret != -EPROBE_DEFER) {
 355                 ret = sdrv->probe(spi);
 356                 if (ret)
 357                         dev_pm_domain_detach(dev, true);
 358         }
 359
 360         return ret;
 361 }
 362
 363 static int spi_drv_remove(struct device *dev)
 364 {
 365         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 366         int ret;
 367
 368         ret = sdrv->remove(to_spi_device(dev));
 369         dev_pm_domain_detach(dev, true);
 370
 371         return ret;
 372 }
 373
 374 static void spi_drv_shutdown(struct device *dev)
 375 {
 376         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 377
 378         sdrv->shutdown(to_spi_device(dev));
 379 }
 380
 381 /**
 382  * __spi_register_driver - register a SPI driver
 383  * @owner: owner module of the driver to register
 384  * @sdrv: the driver to register
 385  * Context: can sleep
 386  *
 387  * Return: zero on success, else a negative error code.
 388  */
 389 int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
 390 {
 391         sdrv->driver.owner = owner;
 392         sdrv->driver.bus = &spi_bus_type;
 393         if (sdrv->probe)
 394                 sdrv->driver.probe = spi_drv_probe;
 395         if (sdrv->remove)
 396                 sdrv->driver.remove = spi_drv_remove;
 397         if (sdrv->shutdown)
 398                 sdrv->driver.shutdown = spi_drv_shutdown;
 399         return driver_register(&sdrv->driver);
 400 }
 401 EXPORT_SYMBOL_GPL(__spi_register_driver);
 402
 403 /*-------------------------------------------------------------------------*/
 404
 405 /* SPI devices should normally not be created by SPI device drivers; that
 406  * would make them board-specific.  Similarly with SPI master drivers.
 407  * Device registration normally goes into like arch/.../mach.../board-YYY.c
 408  * with other readonly (flashable) information about mainboard devices.
 409  */
 410
 411 struct boardinfo {
 412         struct list_head        list;
 413         struct spi_board_info   board_info;
 414 };
 415
 416 static LIST_HEAD(board_list);
 417 static LIST_HEAD(spi_master_list);
 418
 419 /*
 420  * Used to protect add/del opertion for board_info list and
 421  * spi_master list, and their matching process
 422  */
 423 static DEFINE_MUTEX(board_lock);
 424
 425 /**
 426  * spi_alloc_device - Allocate a new SPI device
 427  * @master: Controller to which device is connected
 428  * Context: can sleep
 429  *
 430  * Allows a driver to allocate and initialize a spi_device without
 431  * registering it immediately.  This allows a driver to directly
 432  * fill the spi_device with device parameters before calling
 433  * spi_add_device() on it.
 434  *
 435  * Caller is responsible to call spi_add_device() on the returned
 436  * spi_device structure to add it to the SPI master.  If the caller
 437  * needs to discard the spi_device without adding it, then it should
 438  * call spi_dev_put() on it.
 439  *
 440  * Return: a pointer to the new device, or NULL.
 441  */
 442 struct spi_device *spi_alloc_device(struct spi_master *master)
 443 {
 444         struct spi_device       *spi;
 445
 446         if (!spi_master_get(master))
 447                 return NULL;
 448
 449         spi = kzalloc(sizeof(*spi), GFP_KERNEL);
 450         if (!spi) {
 451                 spi_master_put(master);
 452                 return NULL;
 453         }
 454
 455         spi->master = master;
 456         spi->dev.parent = &master->dev;
 457         spi->dev.bus = &spi_bus_type;
 458         spi->dev.release = spidev_release;
 459         spi->cs_gpio = -ENOENT;
 460
 461         spin_lock_init(&spi->statistics.lock);
 462
 463         device_initialize(&spi->dev);
 464         return spi;
 465 }
 466 EXPORT_SYMBOL_GPL(spi_alloc_device);
 467
 468 static void spi_dev_set_name(struct spi_device *spi)
 469 {
 470         struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
 471
 472         if (adev) {
 473                 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
 474                 return;
 475         }
 476
 477         dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
 478                      spi->chip_select);
 479 }
 480
 481 static int spi_dev_check(struct device *dev, void *data)
 482 {
 483         struct spi_device *spi = to_spi_device(dev);
 484         struct spi_device *new_spi = data;
 485
 486         if (spi->master == new_spi->master &&
 487             spi->chip_select == new_spi->chip_select)
 488                 return -EBUSY;
 489         return 0;
 490 }
 491
 492 /**
 493  * spi_add_device - Add spi_device allocated with spi_alloc_device
 494  * @spi: spi_device to register
 495  *
 496  * Companion function to spi_alloc_device.  Devices allocated with
 497  * spi_alloc_device can be added onto the spi bus with this function.
 498  *
 499  * Return: 0 on success; negative errno on failure
 500  */
 501 int spi_add_device(struct spi_device *spi)
 502 {
 503         static DEFINE_MUTEX(spi_add_lock);
 504         struct spi_master *master = spi->master;
 505         struct device *dev = master->dev.parent;
 506         int status;
 507
 508         /* Chipselects are numbered 0..max; validate. */
 509         if (spi->chip_select >= master->num_chipselect) {
 510                 dev_err(dev, "cs%d >= max %d\n",
 511                         spi->chip_select,
 512                         master->num_chipselect);
 513                 return -EINVAL;
 514         }
 515
 516         /* Set the bus ID string */
 517         spi_dev_set_name(spi);
 518
 519         /* We need to make sure there's no other device with this
 520          * chipselect **BEFORE** we call setup(), else we'll trash
 521          * its configuration.  Lock against concurrent add() calls.
 522          */
 523         mutex_lock(&spi_add_lock);
 524
 525         status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
 526         if (status) {
 527                 dev_err(dev, "chipselect %d already in use\n",
 528                                 spi->chip_select);
 529                 goto done;
 530         }
 531
 532         if (master->cs_gpios)
 533                 spi->cs_gpio = master->cs_gpios[spi->chip_select];
 534
 535         /* Drivers may modify this initial i/o setup, but will
 536          * normally rely on the device being setup.  Devices
 537          * using SPI_CS_HIGH can't coexist well otherwise...
 538          */
 539         status = spi_setup(spi);
 540         if (status < 0) {
 541                 dev_err(dev, "can't setup %s, status %d\n",
 542                                 dev_name(&spi->dev), status);
 543                 goto done;
 544         }
 545
 546         /* Device may be bound to an active driver when this returns */
 547         status = device_add(&spi->dev);
 548         if (status < 0)
 549                 dev_err(dev, "can't add %s, status %d\n",
 550                                 dev_name(&spi->dev), status);
 551         else
 552                 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
 553
 554 done:
 555         mutex_unlock(&spi_add_lock);
 556         return status;
 557 }
 558 EXPORT_SYMBOL_GPL(spi_add_device);
 559
 560 /**
 561  * spi_new_device - instantiate one new SPI device
 562  * @master: Controller to which device is connected
 563  * @chip: Describes the SPI device
 564  * Context: can sleep
 565  *
 566  * On typical mainboards, this is purely internal; and it's not needed
 567  * after board init creates the hard-wired devices.  Some development
 568  * platforms may not be able to use spi_register_board_info though, and
 569  * this is exported so that for example a USB or parport based adapter
 570  * driver could add devices (which it would learn about out-of-band).
 571  *
 572  * Return: the new device, or NULL.
 573  */
 574 struct spi_device *spi_new_device(struct spi_master *master,
 575                                   struct spi_board_info *chip)
 576 {
 577         struct spi_device       *proxy;
 578         int                     status;
 579
 580         /* NOTE:  caller did any chip->bus_num checks necessary.
 581          *
 582          * Also, unless we change the return value convention to use
 583          * error-or-pointer (not NULL-or-pointer), troubleshootability
 584          * suggests syslogged diagnostics are best here (ugh).
 585          */
 586
 587         proxy = spi_alloc_device(master);
 588         if (!proxy)
 589                 return NULL;
 590
 591         WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
 592
 593         proxy->chip_select = chip->chip_select;
 594         proxy->max_speed_hz = chip->max_speed_hz;
 595         proxy->mode = chip->mode;
 596         proxy->irq = chip->irq;
 597         strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
 598         proxy->dev.platform_data = (void *) chip->platform_data;
 599         proxy->controller_data = chip->controller_data;
 600         proxy->controller_state = NULL;
 601
 602         status = spi_add_device(proxy);
 603         if (status < 0) {
 604                 spi_dev_put(proxy);
 605                 return NULL;
 606         }
 607
 608         return proxy;
 609 }
 610 EXPORT_SYMBOL_GPL(spi_new_device);
 611
 612 /**
 613  * spi_unregister_device - unregister a single SPI device
 614  * @spi: spi_device to unregister
 615  *
 616  * Start making the passed SPI device vanish. Normally this would be handled
 617  * by spi_unregister_master().
 618  */
 619 void spi_unregister_device(struct spi_device *spi)
 620 {
 621         if (!spi)
 622                 return;
 623
 624         if (spi->dev.of_node) {
 625                 of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
 626                 of_node_put(spi->dev.of_node);
 627         }
 628         if (ACPI_COMPANION(&spi->dev))
 629                 acpi_device_clear_enumerated(ACPI_COMPANION(&spi->dev));
 630         device_unregister(&spi->dev);
 631 }
 632 EXPORT_SYMBOL_GPL(spi_unregister_device);
 633
 634 static void spi_match_master_to_boardinfo(struct spi_master *master,
 635                                 struct spi_board_info *bi)
 636 {
 637         struct spi_device *dev;
 638
 639         if (master->bus_num != bi->bus_num)
 640                 return;
 641
 642         dev = spi_new_device(master, bi);
 643         if (!dev)
 644                 dev_err(master->dev.parent, "can't create new device for %s\n",
 645                         bi->modalias);
 646 }
 647
 648 /**
 649  * spi_register_board_info - register SPI devices for a given board
 650  * @info: array of chip descriptors
 651  * @n: how many descriptors are provided
 652  * Context: can sleep
 653  *
 654  * Board-specific early init code calls this (probably during arch_initcall)
 655  * with segments of the SPI device table.  Any device nodes are created later,
 656  * after the relevant parent SPI controller (bus_num) is defined.  We keep
 657  * this table of devices forever, so that reloading a controller driver will
 658  * not make Linux forget about these hard-wired devices.
 659  *
 660  * Other code can also call this, e.g. a particular add-on board might provide
 661  * SPI devices through its expansion connector, so code initializing that board
 662  * would naturally declare its SPI devices.
 663  *
 664  * The board info passed can safely be __initdata ... but be careful of
 665  * any embedded pointers (platform_data, etc), they're copied as-is.
 666  *
 667  * Return: zero on success, else a negative error code.
 668  */
 669 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
 670 {
 671         struct boardinfo *bi;
 672         int i;
 673
 674         if (!n)
 675                 return -EINVAL;
 676
 677         bi = kcalloc(n, sizeof(*bi), GFP_KERNEL);
 678         if (!bi)
 679                 return -ENOMEM;
 680
 681         for (i = 0; i < n; i++, bi++, info++) {
 682                 struct spi_master *master;
 683
 684                 memcpy(&bi->board_info, info, sizeof(*info));
 685                 mutex_lock(&board_lock);
 686                 list_add_tail(&bi->list, &board_list);
 687                 list_for_each_entry(master, &spi_master_list, list)
 688                         spi_match_master_to_boardinfo(master, &bi->board_info);
 689                 mutex_unlock(&board_lock);
 690         }
 691
 692         return 0;
 693 }
 694
 695 /*-------------------------------------------------------------------------*/
 696
 697 static void spi_set_cs(struct spi_device *spi, bool enable)
 698 {
 699         if (spi->mode & SPI_CS_HIGH)
 700                 enable = !enable;
 701
 702         if (gpio_is_valid(spi->cs_gpio)) {
 703                 gpio_set_value(spi->cs_gpio, !enable);
 704                 /* Some SPI masters need both GPIO CS & slave_select */
 705                 if ((spi->master->flags & SPI_MASTER_GPIO_SS) &&
 706                     spi->master->set_cs)
 707                         spi->master->set_cs(spi, !enable);
 708         } else if (spi->master->set_cs) {
 709                 spi->master->set_cs(spi, !enable);
 710         }
 711 }
 712
 713 #ifdef CONFIG_HAS_DMA
 714 static int spi_map_buf(struct spi_master *master, struct device *dev,
 715                        struct sg_table *sgt, void *buf, size_t len,
 716                        enum dma_data_direction dir)
 717 {
 718         const bool vmalloced_buf = is_vmalloc_addr(buf);
 719         unsigned int max_seg_size = dma_get_max_seg_size(dev);
 720 #ifdef CONFIG_HIGHMEM
 721         const bool kmap_buf = ((unsigned long)buf >= PKMAP_BASE &&
 722                                 (unsigned long)buf < (PKMAP_BASE +
 723                                         (LAST_PKMAP * PAGE_SIZE)));
 724 #else
 725         const bool kmap_buf = false;
 726 #endif
 727         int desc_len;
 728         int sgs;
 729         struct page *vm_page;
 730         struct scatterlist *sg;
 731         void *sg_buf;
 732         size_t min;
 733         int i, ret;
 734
 735         if (vmalloced_buf || kmap_buf) {
 736                 desc_len = min_t(int, max_seg_size, PAGE_SIZE);
 737                 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
 738         } else if (virt_addr_valid(buf)) {
 739                 desc_len = min_t(int, max_seg_size, master->max_dma_len);
 740                 sgs = DIV_ROUND_UP(len, desc_len);
 741         } else {
 742                 return -EINVAL;
 743         }
 744
 745         ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
 746         if (ret != 0)
 747                 return ret;
 748
 749         sg = &sgt->sgl[0];
 750         for (i = 0; i < sgs; i++) {
 751
 752                 if (vmalloced_buf || kmap_buf) {
 753                         min = min_t(size_t,
 754                                     len, desc_len - offset_in_page(buf));
 755                         if (vmalloced_buf)
 756                                 vm_page = vmalloc_to_page(buf);
 757                         else
 758                                 vm_page = kmap_to_page(buf);
 759                         if (!vm_page) {
 760                                 sg_free_table(sgt);
 761                                 return -ENOMEM;
 762                         }
 763                         sg_set_page(sg, vm_page,
 764                                     min, offset_in_page(buf));
 765                 } else {
 766                         min = min_t(size_t, len, desc_len);
 767                         sg_buf = buf;
 768                         sg_set_buf(sg, sg_buf, min);
 769                 }
 770
 771                 buf += min;
 772                 len -= min;
 773                 sg = sg_next(sg);
 774         }
 775
 776         ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
 777         if (!ret)
 778                 ret = -ENOMEM;
 779         if (ret < 0) {
 780                 sg_free_table(sgt);
 781                 return ret;
 782         }
 783
 784         sgt->nents = ret;
 785
 786         return 0;
 787 }
 788
 789 static void spi_unmap_buf(struct spi_master *master, struct device *dev,
 790                           struct sg_table *sgt, enum dma_data_direction dir)
 791 {
 792         if (sgt->orig_nents) {
 793                 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
 794                 sg_free_table(sgt);
 795         }
 796 }
 797
 798 static int __spi_map_msg(struct spi_master *master, struct spi_message *msg)
 799 {
 800         struct device *tx_dev, *rx_dev;
 801         struct spi_transfer *xfer;
 802         int ret;
 803
 804         if (!master->can_dma)
 805                 return 0;
 806
 807         if (master->dma_tx)
 808                 tx_dev = master->dma_tx->device->dev;
 809         else
 810                 tx_dev = master->dev.parent;
 811
 812         if (master->dma_rx)
 813                 rx_dev = master->dma_rx->device->dev;
 814         else
 815                 rx_dev = master->dev.parent;
 816
 817         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 818                 if (!master->can_dma(master, msg->spi, xfer))
 819                         continue;
 820
 821                 if (xfer->tx_buf != NULL) {
 822                         ret = spi_map_buf(master, tx_dev, &xfer->tx_sg,
 823                                           (void *)xfer->tx_buf, xfer->len,
 824                                           DMA_TO_DEVICE);
 825                         if (ret != 0)
 826                                 return ret;
 827                 }
 828
 829                 if (xfer->rx_buf != NULL) {
 830                         ret = spi_map_buf(master, rx_dev, &xfer->rx_sg,
 831                                           xfer->rx_buf, xfer->len,
 832                                           DMA_FROM_DEVICE);
 833                         if (ret != 0) {
 834                                 spi_unmap_buf(master, tx_dev, &xfer->tx_sg,
 835                                               DMA_TO_DEVICE);
 836                                 return ret;
 837                         }
 838                 }
 839         }
 840
 841         master->cur_msg_mapped = true;
 842
 843         return 0;
 844 }
 845
 846 static int __spi_unmap_msg(struct spi_master *master, struct spi_message *msg)
 847 {
 848         struct spi_transfer *xfer;
 849         struct device *tx_dev, *rx_dev;
 850
 851         if (!master->cur_msg_mapped || !master->can_dma)
 852                 return 0;
 853
 854         if (master->dma_tx)
 855                 tx_dev = master->dma_tx->device->dev;
 856         else
 857                 tx_dev = master->dev.parent;
 858
 859         if (master->dma_rx)
 860                 rx_dev = master->dma_rx->device->dev;
 861         else
 862                 rx_dev = master->dev.parent;
 863
 864         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 865                 if (!master->can_dma(master, msg->spi, xfer))
 866                         continue;
 867
 868                 spi_unmap_buf(master, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
 869                 spi_unmap_buf(master, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
 870         }
 871
 872         return 0;
 873 }
 874 #else /* !CONFIG_HAS_DMA */
 875 static inline int spi_map_buf(struct spi_master *master,
 876                               struct device *dev, struct sg_table *sgt,
 877                               void *buf, size_t len,
 878                               enum dma_data_direction dir)
 879 {
 880         return -EINVAL;
 881 }
 882
 883 static inline void spi_unmap_buf(struct spi_master *master,
 884                                  struct device *dev, struct sg_table *sgt,
 885                                  enum dma_data_direction dir)
 886 {
 887 }
 888
 889 static inline int __spi_map_msg(struct spi_master *master,
 890                                 struct spi_message *msg)
 891 {
 892         return 0;
 893 }
 894
 895 static inline int __spi_unmap_msg(struct spi_master *master,
 896                                   struct spi_message *msg)
 897 {
 898         return 0;
 899 }
 900 #endif /* !CONFIG_HAS_DMA */
 901
 902 static inline int spi_unmap_msg(struct spi_master *master,
 903                                 struct spi_message *msg)
 904 {
 905         struct spi_transfer *xfer;
 906
 907         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 908                 /*
 909                  * Restore the original value of tx_buf or rx_buf if they are
 910                  * NULL.
 911                  */
 912                 if (xfer->tx_buf == master->dummy_tx)
 913                         xfer->tx_buf = NULL;
 914                 if (xfer->rx_buf == master->dummy_rx)
 915                         xfer->rx_buf = NULL;
 916         }
 917
 918         return __spi_unmap_msg(master, msg);
 919 }
 920
 921 static int spi_map_msg(struct spi_master *master, struct spi_message *msg)
 922 {
 923         struct spi_transfer *xfer;
 924         void *tmp;
 925         unsigned int max_tx, max_rx;
 926
 927         if (master->flags & (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX)) {
 928                 max_tx = 0;
 929                 max_rx = 0;
 930
 931                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 932                         if ((master->flags & SPI_MASTER_MUST_TX) &&
 933                             !xfer->tx_buf)
 934                                 max_tx = max(xfer->len, max_tx);
 935                         if ((master->flags & SPI_MASTER_MUST_RX) &&
 936                             !xfer->rx_buf)
 937                                 max_rx = max(xfer->len, max_rx);
 938                 }
 939
 940                 if (max_tx) {
 941                         tmp = krealloc(master->dummy_tx, max_tx,
 942                                        GFP_KERNEL | GFP_DMA);
 943                         if (!tmp)
 944                                 return -ENOMEM;
 945                         master->dummy_tx = tmp;
 946                         memset(tmp, 0, max_tx);
 947                 }
 948
 949                 if (max_rx) {
 950                         tmp = krealloc(master->dummy_rx, max_rx,
 951                                        GFP_KERNEL | GFP_DMA);
 952                         if (!tmp)
 953                                 return -ENOMEM;
 954                         master->dummy_rx = tmp;
 955                 }
 956
 957                 if (max_tx || max_rx) {
 958                         list_for_each_entry(xfer, &msg->transfers,
 959                                             transfer_list) {
 960                                 if (!xfer->tx_buf)
 961                                         xfer->tx_buf = master->dummy_tx;
 962                                 if (!xfer->rx_buf)
 963                                         xfer->rx_buf = master->dummy_rx;
 964                         }
 965                 }
 966         }
 967
 968         return __spi_map_msg(master, msg);
 969 }
 970
 971 /*
 972  * spi_transfer_one_message - Default implementation of transfer_one_message()
 973  *
 974  * This is a standard implementation of transfer_one_message() for
 975  * drivers which implement a transfer_one() operation.  It provides
 976  * standard handling of delays and chip select management.
 977  */
 978 static int spi_transfer_one_message(struct spi_master *master,
 979                                     struct spi_message *msg)
 980 {
 981         struct spi_transfer *xfer;
 982         bool keep_cs = false;
 983         int ret = 0;
 984         unsigned long long ms = 1;
 985         struct spi_statistics *statm = &master->statistics;
 986         struct spi_statistics *stats = &msg->spi->statistics;
 987
 988         spi_set_cs(msg->spi, true);
 989
 990         SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
 991         SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
 992
 993         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 994                 trace_spi_transfer_start(msg, xfer);
 995
 996                 spi_statistics_add_transfer_stats(statm, xfer, master);
 997                 spi_statistics_add_transfer_stats(stats, xfer, master);
 998
 999                 if (xfer->tx_buf || xfer->rx_buf) {
1000                         reinit_completion(&master->xfer_completion);
1001
1002                         ret = master->transfer_one(master, msg->spi, xfer);
1003                         if (ret < 0) {
1004                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
1005                                                                errors);
1006                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
1007                                                                errors);
1008                                 dev_err(&msg->spi->dev,
1009                                         "SPI transfer failed: %d\n", ret);
1010                                 goto out;
1011                         }
1012
1013                         if (ret > 0) {
1014                                 ret = 0;
1015                                 ms = 8LL * 1000LL * xfer->len;
1016                                 do_div(ms, xfer->speed_hz);
1017                                 ms += ms + 100; /* some tolerance */
1018
1019                                 if (ms > UINT_MAX)
1020                                         ms = UINT_MAX;
1021
1022                                 ms = wait_for_completion_timeout(&master->xfer_completion,
1023                                                                  msecs_to_jiffies(ms));
1024                         }
1025
1026                         if (ms == 0) {
1027                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
1028                                                                timedout);
1029                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
1030                                                                timedout);
1031                                 dev_err(&msg->spi->dev,
1032                                         "SPI transfer timed out\n");
1033                                 msg->status = -ETIMEDOUT;
1034                         }
1035                 } else {
1036                         if (xfer->len)
1037                                 dev_err(&msg->spi->dev,
1038                                         "Bufferless transfer has length %u\n",
1039                                         xfer->len);
1040                 }
1041
1042                 trace_spi_transfer_stop(msg, xfer);
1043
1044                 if (msg->status != -EINPROGRESS)
1045                         goto out;
1046
1047                 if (xfer->delay_usecs) {
1048                         u16 us = xfer->delay_usecs;
1049
1050                         if (us <= 10)
1051                                 udelay(us);
1052                         else
1053                                 usleep_range(us, us + DIV_ROUND_UP(us, 10));
1054                 }
1055
1056                 if (xfer->cs_change) {
1057                         if (list_is_last(&xfer->transfer_list,
1058                                          &msg->transfers)) {
1059                                 keep_cs = true;
1060                         } else {
1061                                 spi_set_cs(msg->spi, false);
1062                                 udelay(10);
1063                                 spi_set_cs(msg->spi, true);
1064                         }
1065                 }
1066
1067                 msg->actual_length += xfer->len;
1068         }
1069
1070 out:
1071         if (ret != 0 || !keep_cs)
1072                 spi_set_cs(msg->spi, false);
1073
1074         if (msg->status == -EINPROGRESS)
1075                 msg->status = ret;
1076
1077         if (msg->status && master->handle_err)
1078                 master->handle_err(master, msg);
1079
1080         spi_res_release(master, msg);
1081
1082         spi_finalize_current_message(master);
1083
1084         return ret;
1085 }
1086
1087 /**
1088  * spi_finalize_current_transfer - report completion of a transfer
1089  * @master: the master reporting completion
1090  *
1091  * Called by SPI drivers using the core transfer_one_message()
1092  * implementation to notify it that the current interrupt driven
1093  * transfer has finished and the next one may be scheduled.
1094  */
1095 void spi_finalize_current_transfer(struct spi_master *master)
1096 {
1097         complete(&master->xfer_completion);
1098 }
1099 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1100
1101 /**
1102  * __spi_pump_messages - function which processes spi message queue
1103  * @master: master to process queue for
1104  * @in_kthread: true if we are in the context of the message pump thread
1105  *
1106  * This function checks if there is any spi message in the queue that
1107  * needs processing and if so call out to the driver to initialize hardware
1108  * and transfer each message.
1109  *
1110  * Note that it is called both from the kthread itself and also from
1111  * inside spi_sync(); the queue extraction handling at the top of the
1112  * function should deal with this safely.
1113  */
1114 static void __spi_pump_messages(struct spi_master *master, bool in_kthread)
1115 {
1116         unsigned long flags;
1117         bool was_busy = false;
1118         int ret;
1119
1120         /* Lock queue */
1121         spin_lock_irqsave(&master->queue_lock, flags);
1122
1123         /* Make sure we are not already running a message */
1124         if (master->cur_msg) {
1125                 spin_unlock_irqrestore(&master->queue_lock, flags);
1126                 return;
1127         }
1128
1129         /* If another context is idling the device then defer */
1130         if (master->idling) {
1131                 kthread_queue_work(&master->kworker, &master->pump_messages);
1132                 spin_unlock_irqrestore(&master->queue_lock, flags);
1133                 return;
1134         }
1135
1136         /* Check if the queue is idle */
1137         if (list_empty(&master->queue) || !master->running) {
1138                 if (!master->busy) {
1139                         spin_unlock_irqrestore(&master->queue_lock, flags);
1140                         return;
1141                 }
1142
1143                 /* Only do teardown in the thread */
1144                 if (!in_kthread) {
1145                         kthread_queue_work(&master->kworker,
1146                                            &master->pump_messages);
1147                         spin_unlock_irqrestore(&master->queue_lock, flags);
1148                         return;
1149                 }
1150
1151                 master->busy = false;
1152                 master->idling = true;
1153                 spin_unlock_irqrestore(&master->queue_lock, flags);
1154
1155                 kfree(master->dummy_rx);
1156                 master->dummy_rx = NULL;
1157                 kfree(master->dummy_tx);
1158                 master->dummy_tx = NULL;
1159                 if (master->unprepare_transfer_hardware &&
1160                     master->unprepare_transfer_hardware(master))
1161                         dev_err(&master->dev,
1162                                 "failed to unprepare transfer hardware\n");
1163                 if (master->auto_runtime_pm) {
1164                         pm_runtime_mark_last_busy(master->dev.parent);
1165                         pm_runtime_put_autosuspend(master->dev.parent);
1166                 }
1167                 trace_spi_master_idle(master);
1168
1169                 spin_lock_irqsave(&master->queue_lock, flags);
1170                 master->idling = false;
1171                 spin_unlock_irqrestore(&master->queue_lock, flags);
1172                 return;
1173         }
1174
1175         /* Extract head of queue */
1176         master->cur_msg =
1177                 list_first_entry(&master->queue, struct spi_message, queue);
1178
1179         list_del_init(&master->cur_msg->queue);
1180         if (master->busy)
1181                 was_busy = true;
1182         else
1183                 master->busy = true;
1184         spin_unlock_irqrestore(&master->queue_lock, flags);
1185
1186         mutex_lock(&master->io_mutex);
1187
1188         if (!was_busy && master->auto_runtime_pm) {
1189                 ret = pm_runtime_get_sync(master->dev.parent);
1190                 if (ret < 0) {
1191                         dev_err(&master->dev, "Failed to power device: %d\n",
1192                                 ret);
1193                         mutex_unlock(&master->io_mutex);
1194                         return;
1195                 }
1196         }
1197
1198         if (!was_busy)
1199                 trace_spi_master_busy(master);
1200
1201         if (!was_busy && master->prepare_transfer_hardware) {
1202                 ret = master->prepare_transfer_hardware(master);
1203                 if (ret) {
1204                         dev_err(&master->dev,
1205                                 "failed to prepare transfer hardware\n");
1206
1207                         if (master->auto_runtime_pm)
1208                                 pm_runtime_put(master->dev.parent);
1209                         mutex_unlock(&master->io_mutex);
1210                         return;
1211                 }
1212         }
1213
1214         trace_spi_message_start(master->cur_msg);
1215
1216         if (master->prepare_message) {
1217                 ret = master->prepare_message(master, master->cur_msg);
1218                 if (ret) {
1219                         dev_err(&master->dev,
1220                                 "failed to prepare message: %d\n", ret);
1221                         master->cur_msg->status = ret;
1222                         spi_finalize_current_message(master);
1223                         goto out;
1224                 }
1225                 master->cur_msg_prepared = true;
1226         }
1227
1228         ret = spi_map_msg(master, master->cur_msg);
1229         if (ret) {
1230                 master->cur_msg->status = ret;
1231                 spi_finalize_current_message(master);
1232                 goto out;
1233         }
1234
1235         ret = master->transfer_one_message(master, master->cur_msg);
1236         if (ret) {
1237                 dev_err(&master->dev,
1238                         "failed to transfer one message from queue\n");
1239                 goto out;
1240         }
1241
1242 out:
1243         mutex_unlock(&master->io_mutex);
1244
1245         /* Prod the scheduler in case transfer_one() was busy waiting */
1246         if (!ret)
1247                 cond_resched();
1248 }
1249
1250 /**
1251  * spi_pump_messages - kthread work function which processes spi message queue
1252  * @work: pointer to kthread work struct contained in the master struct
1253  */
1254 static void spi_pump_messages(struct kthread_work *work)
1255 {
1256         struct spi_master *master =
1257                 container_of(work, struct spi_master, pump_messages);
1258
1259         __spi_pump_messages(master, true);
1260 }
1261
1262 static int spi_init_queue(struct spi_master *master)
1263 {
1264         struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
1265
1266         master->running = false;
1267         master->busy = false;
1268
1269         kthread_init_worker(&master->kworker);
1270         master->kworker_task = kthread_run(kthread_worker_fn,
1271                                            &master->kworker, "%s",
1272                                            dev_name(&master->dev));
1273         if (IS_ERR(master->kworker_task)) {
1274                 dev_err(&master->dev, "failed to create message pump task\n");
1275                 return PTR_ERR(master->kworker_task);
1276         }
1277         kthread_init_work(&master->pump_messages, spi_pump_messages);
1278
1279         /*
1280          * Master config will indicate if this controller should run the
1281          * message pump with high (realtime) priority to reduce the transfer
1282          * latency on the bus by minimising the delay between a transfer
1283          * request and the scheduling of the message pump thread. Without this
1284          * setting the message pump thread will remain at default priority.
1285          */
1286         if (master->rt) {
1287                 dev_info(&master->dev,
1288                         "will run message pump with realtime priority\n");
1289                 sched_setscheduler(master->kworker_task, SCHED_FIFO, &param);
1290         }
1291
1292         return 0;
1293 }
1294
1295 /**
1296  * spi_get_next_queued_message() - called by driver to check for queued
1297  * messages
1298  * @master: the master to check for queued messages
1299  *
1300  * If there are more messages in the queue, the next message is returned from
1301  * this call.
1302  *
1303  * Return: the next message in the queue, else NULL if the queue is empty.
1304  */
1305 struct spi_message *spi_get_next_queued_message(struct spi_master *master)
1306 {
1307         struct spi_message *next;
1308         unsigned long flags;
1309
1310         /* get a pointer to the next message, if any */
1311         spin_lock_irqsave(&master->queue_lock, flags);
1312         next = list_first_entry_or_null(&master->queue, struct spi_message,
1313                                         queue);
1314         spin_unlock_irqrestore(&master->queue_lock, flags);
1315
1316         return next;
1317 }
1318 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1319
1320 /**
1321  * spi_finalize_current_message() - the current message is complete
1322  * @master: the master to return the message to
1323  *
1324  * Called by the driver to notify the core that the message in the front of the
1325  * queue is complete and can be removed from the queue.
1326  */
1327 void spi_finalize_current_message(struct spi_master *master)
1328 {
1329         struct spi_message *mesg;
1330         unsigned long flags;
1331         int ret;
1332
1333         spin_lock_irqsave(&master->queue_lock, flags);
1334         mesg = master->cur_msg;
1335         spin_unlock_irqrestore(&master->queue_lock, flags);
1336
1337         spi_unmap_msg(master, mesg);
1338
1339         if (master->cur_msg_prepared && master->unprepare_message) {
1340                 ret = master->unprepare_message(master, mesg);
1341                 if (ret) {
1342                         dev_err(&master->dev,
1343                                 "failed to unprepare message: %d\n", ret);
1344                 }
1345         }
1346
1347         spin_lock_irqsave(&master->queue_lock, flags);
1348         master->cur_msg = NULL;
1349         master->cur_msg_prepared = false;
1350         kthread_queue_work(&master->kworker, &master->pump_messages);
1351         spin_unlock_irqrestore(&master->queue_lock, flags);
1352
1353         trace_spi_message_done(mesg);
1354
1355         mesg->state = NULL;
1356         if (mesg->complete)
1357                 mesg->complete(mesg->context);
1358 }
1359 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1360
1361 static int spi_start_queue(struct spi_master *master)
1362 {
1363         unsigned long flags;
1364
1365         spin_lock_irqsave(&master->queue_lock, flags);
1366
1367         if (master->running || master->busy) {
1368                 spin_unlock_irqrestore(&master->queue_lock, flags);
1369                 return -EBUSY;
1370         }
1371
1372         master->running = true;
1373         master->cur_msg = NULL;
1374         spin_unlock_irqrestore(&master->queue_lock, flags);
1375
1376         kthread_queue_work(&master->kworker, &master->pump_messages);
1377
1378         return 0;
1379 }
1380
1381 static int spi_stop_queue(struct spi_master *master)
1382 {
1383         unsigned long flags;
1384         unsigned limit = 500;
1385         int ret = 0;
1386
1387         spin_lock_irqsave(&master->queue_lock, flags);
1388
1389         /*
1390          * This is a bit lame, but is optimized for the common execution path.
1391          * A wait_queue on the master->busy could be used, but then the common
1392          * execution path (pump_messages) would be required to call wake_up or
1393          * friends on every SPI message. Do this instead.
1394          */
1395         while ((!list_empty(&master->queue) || master->busy) && limit--) {
1396                 spin_unlock_irqrestore(&master->queue_lock, flags);
1397                 usleep_range(10000, 11000);
1398                 spin_lock_irqsave(&master->queue_lock, flags);
1399         }
1400
1401         if (!list_empty(&master->queue) || master->busy)
1402                 ret = -EBUSY;
1403         else
1404                 master->running = false;
1405
1406         spin_unlock_irqrestore(&master->queue_lock, flags);
1407
1408         if (ret) {
1409                 dev_warn(&master->dev,
1410                          "could not stop message queue\n");
1411                 return ret;
1412         }
1413         return ret;
1414 }
1415
1416 static int spi_destroy_queue(struct spi_master *master)
1417 {
1418         int ret;
1419
1420         ret = spi_stop_queue(master);
1421
1422         /*
1423          * kthread_flush_worker will block until all work is done.
1424          * If the reason that stop_queue timed out is that the work will never
1425          * finish, then it does no good to call flush/stop thread, so
1426          * return anyway.
1427          */
1428         if (ret) {
1429                 dev_err(&master->dev, "problem destroying queue\n");
1430                 return ret;
1431         }
1432
1433         kthread_flush_worker(&master->kworker);
1434         kthread_stop(master->kworker_task);
1435
1436         return 0;
1437 }
1438
1439 static int __spi_queued_transfer(struct spi_device *spi,
1440                                  struct spi_message *msg,
1441                                  bool need_pump)
1442 {
1443         struct spi_master *master = spi->master;
1444         unsigned long flags;
1445
1446         spin_lock_irqsave(&master->queue_lock, flags);
1447
1448         if (!master->running) {
1449                 spin_unlock_irqrestore(&master->queue_lock, flags);
1450                 return -ESHUTDOWN;
1451         }
1452         msg->actual_length = 0;
1453         msg->status = -EINPROGRESS;
1454
1455         list_add_tail(&msg->queue, &master->queue);
1456         if (!master->busy && need_pump)
1457                 kthread_queue_work(&master->kworker, &master->pump_messages);
1458
1459         spin_unlock_irqrestore(&master->queue_lock, flags);
1460         return 0;
1461 }
1462
1463 /**
1464  * spi_queued_transfer - transfer function for queued transfers
1465  * @spi: spi device which is requesting transfer
1466  * @msg: spi message which is to handled is queued to driver queue
1467  *
1468  * Return: zero on success, else a negative error code.
1469  */
1470 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1471 {
1472         return __spi_queued_transfer(spi, msg, true);
1473 }
1474
1475 static int spi_master_initialize_queue(struct spi_master *master)
1476 {
1477         int ret;
1478
1479         master->transfer = spi_queued_transfer;
1480         if (!master->transfer_one_message)
1481                 master->transfer_one_message = spi_transfer_one_message;
1482
1483         /* Initialize and start queue */
1484         ret = spi_init_queue(master);
1485         if (ret) {
1486                 dev_err(&master->dev, "problem initializing queue\n");
1487                 goto err_init_queue;
1488         }
1489         master->queued = true;
1490         ret = spi_start_queue(master);
1491         if (ret) {
1492                 dev_err(&master->dev, "problem starting queue\n");
1493                 goto err_start_queue;
1494         }
1495
1496         return 0;
1497
1498 err_start_queue:
1499         spi_destroy_queue(master);
1500 err_init_queue:
1501         return ret;
1502 }
1503
1504 /*-------------------------------------------------------------------------*/
1505
1506 #if defined(CONFIG_OF)
1507 static int of_spi_parse_dt(struct spi_master *master, struct spi_device *spi,
1508                            struct device_node *nc)
1509 {
1510         u32 value;
1511         int rc;
1512
1513         /* Device address */
1514         rc = of_property_read_u32(nc, "reg", &value);
1515         if (rc) {
1516                 dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
1517                         nc->full_name, rc);
1518                 return rc;
1519         }
1520         spi->chip_select = value;
1521
1522         /* Mode (clock phase/polarity/etc.) */
1523         if (of_find_property(nc, "spi-cpha", NULL))
1524                 spi->mode |= SPI_CPHA;
1525         if (of_find_property(nc, "spi-cpol", NULL))
1526                 spi->mode |= SPI_CPOL;
1527         if (of_find_property(nc, "spi-cs-high", NULL))
1528                 spi->mode |= SPI_CS_HIGH;
1529         if (of_find_property(nc, "spi-3wire", NULL))
1530                 spi->mode |= SPI_3WIRE;
1531         if (of_find_property(nc, "spi-lsb-first", NULL))
1532                 spi->mode |= SPI_LSB_FIRST;
1533
1534         /* Device DUAL/QUAD mode */
1535         if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1536                 switch (value) {
1537                 case 1:
1538                         break;
1539                 case 2:
1540                         spi->mode |= SPI_TX_DUAL;
1541                         break;
1542                 case 4:
1543                         spi->mode |= SPI_TX_QUAD;
1544                         break;
1545                 default:
1546                         dev_warn(&master->dev,
1547                                 "spi-tx-bus-width %d not supported\n",
1548                                 value);
1549                         break;
1550                 }
1551         }
1552
1553         if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1554                 switch (value) {
1555                 case 1:
1556                         break;
1557                 case 2:
1558                         spi->mode |= SPI_RX_DUAL;
1559                         break;
1560                 case 4:
1561                         spi->mode |= SPI_RX_QUAD;
1562                         break;
1563                 default:
1564                         dev_warn(&master->dev,
1565                                 "spi-rx-bus-width %d not supported\n",
1566                                 value);
1567                         break;
1568                 }
1569         }
1570
1571         /* Device speed */
1572         rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1573         if (rc) {
1574                 dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
1575                         nc->full_name, rc);
1576                 return rc;
1577         }
1578         spi->max_speed_hz = value;
1579
1580         return 0;
1581 }
1582
1583 static struct spi_device *
1584 of_register_spi_device(struct spi_master *master, struct device_node *nc)
1585 {
1586         struct spi_device *spi;
1587         int rc;
1588
1589         /* Alloc an spi_device */
1590         spi = spi_alloc_device(master);
1591         if (!spi) {
1592                 dev_err(&master->dev, "spi_device alloc error for %s\n",
1593                         nc->full_name);
1594                 rc = -ENOMEM;
1595                 goto err_out;
1596         }
1597
1598         /* Select device driver */
1599         rc = of_modalias_node(nc, spi->modalias,
1600                                 sizeof(spi->modalias));
1601         if (rc < 0) {
1602                 dev_err(&master->dev, "cannot find modalias for %s\n",
1603                         nc->full_name);
1604                 goto err_out;
1605         }
1606
1607         rc = of_spi_parse_dt(master, spi, nc);
1608         if (rc)
1609                 goto err_out;
1610
1611         /* Store a pointer to the node in the device structure */
1612         of_node_get(nc);
1613         spi->dev.of_node = nc;
1614
1615         /* Register the new device */
1616         rc = spi_add_device(spi);
1617         if (rc) {
1618                 dev_err(&master->dev, "spi_device register error %s\n",
1619                         nc->full_name);
1620                 goto err_of_node_put;
1621         }
1622
1623         return spi;
1624
1625 err_of_node_put:
1626         of_node_put(nc);
1627 err_out:
1628         spi_dev_put(spi);
1629         return ERR_PTR(rc);
1630 }
1631
1632 /**
1633  * of_register_spi_devices() - Register child devices onto the SPI bus
1634  * @master:     Pointer to spi_master device
1635  *
1636  * Registers an spi_device for each child node of master node which has a 'reg'
1637  * property.
1638  */
1639 static void of_register_spi_devices(struct spi_master *master)
1640 {
1641         struct spi_device *spi;
1642         struct device_node *nc;
1643
1644         if (!master->dev.of_node)
1645                 return;
1646
1647         for_each_available_child_of_node(master->dev.of_node, nc) {
1648                 if (of_node_test_and_set_flag(nc, OF_POPULATED))
1649                         continue;
1650                 spi = of_register_spi_device(master, nc);
1651                 if (IS_ERR(spi)) {
1652                         dev_warn(&master->dev, "Failed to create SPI device for %s\n",
1653                                 nc->full_name);
1654                         of_node_clear_flag(nc, OF_POPULATED);
1655                 }
1656         }
1657 }
1658 #else
1659 static void of_register_spi_devices(struct spi_master *master) { }
1660 #endif
1661
1662 #ifdef CONFIG_ACPI
1663 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1664 {
1665         struct spi_device *spi = data;
1666         struct spi_master *master = spi->master;
1667
1668         if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1669                 struct acpi_resource_spi_serialbus *sb;
1670
1671                 sb = &ares->data.spi_serial_bus;
1672                 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1673                         /*
1674                          * ACPI DeviceSelection numbering is handled by the
1675                          * host controller driver in Windows and can vary
1676                          * from driver to driver. In Linux we always expect
1677                          * 0 .. max - 1 so we need to ask the driver to
1678                          * translate between the two schemes.
1679                          */
1680                         if (master->fw_translate_cs) {
1681                                 int cs = master->fw_translate_cs(master,
1682                                                 sb->device_selection);
1683                                 if (cs < 0)
1684                                         return cs;
1685                                 spi->chip_select = cs;
1686                         } else {
1687                                 spi->chip_select = sb->device_selection;
1688                         }
1689
1690                         spi->max_speed_hz = sb->connection_speed;
1691
1692                         if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1693                                 spi->mode |= SPI_CPHA;
1694                         if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1695                                 spi->mode |= SPI_CPOL;
1696                         if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1697                                 spi->mode |= SPI_CS_HIGH;
1698                 }
1699         } else if (spi->irq < 0) {
1700                 struct resource r;
1701
1702                 if (acpi_dev_resource_interrupt(ares, 0, &r))
1703                         spi->irq = r.start;
1704         }
1705
1706         /* Always tell the ACPI core to skip this resource */
1707         return 1;
1708 }
1709
1710 static acpi_status acpi_register_spi_device(struct spi_master *master,
1711                                             struct acpi_device *adev)
1712 {
1713         struct list_head resource_list;
1714         struct spi_device *spi;
1715         int ret;
1716
1717         if (acpi_bus_get_status(adev) || !adev->status.present ||
1718             acpi_device_enumerated(adev))
1719                 return AE_OK;
1720
1721         spi = spi_alloc_device(master);
1722         if (!spi) {
1723                 dev_err(&master->dev, "failed to allocate SPI device for %s\n",
1724                         dev_name(&adev->dev));
1725                 return AE_NO_MEMORY;
1726         }
1727
1728         ACPI_COMPANION_SET(&spi->dev, adev);
1729         spi->irq = -1;
1730
1731         INIT_LIST_HEAD(&resource_list);
1732         ret = acpi_dev_get_resources(adev, &resource_list,
1733                                      acpi_spi_add_resource, spi);
1734         acpi_dev_free_resource_list(&resource_list);
1735
1736         if (ret < 0 || !spi->max_speed_hz) {
1737                 spi_dev_put(spi);
1738                 return AE_OK;
1739         }
1740
1741         acpi_set_modalias(adev, acpi_device_hid(adev), spi->modalias,
1742                           sizeof(spi->modalias));
1743
1744         if (spi->irq < 0)
1745                 spi->irq = acpi_dev_gpio_irq_get(adev, 0);
1746
1747         acpi_device_set_enumerated(adev);
1748
1749         adev->power.flags.ignore_parent = true;
1750         if (spi_add_device(spi)) {
1751                 adev->power.flags.ignore_parent = false;
1752                 dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
1753                         dev_name(&adev->dev));
1754                 spi_dev_put(spi);
1755         }
1756
1757         return AE_OK;
1758 }
1759
1760 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1761                                        void *data, void **return_value)
1762 {
1763         struct spi_master *master = data;
1764         struct acpi_device *adev;
1765
1766         if (acpi_bus_get_device(handle, &adev))
1767                 return AE_OK;
1768
1769         return acpi_register_spi_device(master, adev);
1770 }
1771
1772 static void acpi_register_spi_devices(struct spi_master *master)
1773 {
1774         acpi_status status;
1775         acpi_handle handle;
1776
1777         handle = ACPI_HANDLE(master->dev.parent);
1778         if (!handle)
1779                 return;
1780
1781         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1782                                      acpi_spi_add_device, NULL,
1783                                      master, NULL);
1784         if (ACPI_FAILURE(status))
1785                 dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
1786 }
1787 #else
1788 static inline void acpi_register_spi_devices(struct spi_master *master) {}
1789 #endif /* CONFIG_ACPI */
1790
1791 static void spi_master_release(struct device *dev)
1792 {
1793         struct spi_master *master;
1794
1795         master = container_of(dev, struct spi_master, dev);
1796         kfree(master);
1797 }
1798
1799 static struct class spi_master_class = {
1800         .name           = "spi_master",
1801         .owner          = THIS_MODULE,
1802         .dev_release    = spi_master_release,
1803         .dev_groups     = spi_master_groups,
1804 };
1805
1806
1807 /**
1808  * spi_alloc_master - allocate SPI master controller
1809  * @dev: the controller, possibly using the platform_bus
1810  * @size: how much zeroed driver-private data to allocate; the pointer to this
1811  *      memory is in the driver_data field of the returned device,
1812  *      accessible with spi_master_get_devdata().
1813  * Context: can sleep
1814  *
1815  * This call is used only by SPI master controller drivers, which are the
1816  * only ones directly touching chip registers.  It's how they allocate
1817  * an spi_master structure, prior to calling spi_register_master().
1818  *
1819  * This must be called from context that can sleep.
1820  *
1821  * The caller is responsible for assigning the bus number and initializing
1822  * the master's methods before calling spi_register_master(); and (after errors
1823  * adding the device) calling spi_master_put() to prevent a memory leak.
1824  *
1825  * Return: the SPI master structure on success, else NULL.
1826  */
1827 struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
1828 {
1829         struct spi_master       *master;
1830
1831         if (!dev)
1832                 return NULL;
1833
1834         master = kzalloc(size + sizeof(*master), GFP_KERNEL);
1835         if (!master)
1836                 return NULL;
1837
1838         device_initialize(&master->dev);
1839         master->bus_num = -1;
1840         master->num_chipselect = 1;
1841         master->dev.class = &spi_master_class;
1842         master->dev.parent = dev;
1843         pm_suspend_ignore_children(&master->dev, true);
1844         spi_master_set_devdata(master, &master[1]);
1845
1846         return master;
1847 }
1848 EXPORT_SYMBOL_GPL(spi_alloc_master);
1849
1850 #ifdef CONFIG_OF
1851 static int of_spi_register_master(struct spi_master *master)
1852 {
1853         int nb, i, *cs;
1854         struct device_node *np = master->dev.of_node;
1855
1856         if (!np)
1857                 return 0;
1858
1859         nb = of_gpio_named_count(np, "cs-gpios");
1860         master->num_chipselect = max_t(int, nb, master->num_chipselect);
1861
1862         /* Return error only for an incorrectly formed cs-gpios property */
1863         if (nb == 0 || nb == -ENOENT)
1864                 return 0;
1865         else if (nb < 0)
1866                 return nb;
1867
1868         cs = devm_kzalloc(&master->dev,
1869                           sizeof(int) * master->num_chipselect,
1870                           GFP_KERNEL);
1871         master->cs_gpios = cs;
1872
1873         if (!master->cs_gpios)
1874                 return -ENOMEM;
1875
1876         for (i = 0; i < master->num_chipselect; i++)
1877                 cs[i] = -ENOENT;
1878
1879         for (i = 0; i < nb; i++)
1880                 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
1881
1882         return 0;
1883 }
1884 #else
1885 static int of_spi_register_master(struct spi_master *master)
1886 {
1887         return 0;
1888 }
1889 #endif
1890
1891 /**
1892  * spi_register_master - register SPI master controller
1893  * @master: initialized master, originally from spi_alloc_master()
1894  * Context: can sleep
1895  *
1896  * SPI master controllers connect to their drivers using some non-SPI bus,
1897  * such as the platform bus.  The final stage of probe() in that code
1898  * includes calling spi_register_master() to hook up to this SPI bus glue.
1899  *
1900  * SPI controllers use board specific (often SOC specific) bus numbers,
1901  * and board-specific addressing for SPI devices combines those numbers
1902  * with chip select numbers.  Since SPI does not directly support dynamic
1903  * device identification, boards need configuration tables telling which
1904  * chip is at which address.
1905  *
1906  * This must be called from context that can sleep.  It returns zero on
1907  * success, else a negative error code (dropping the master's refcount).
1908  * After a successful return, the caller is responsible for calling
1909  * spi_unregister_master().
1910  *
1911  * Return: zero on success, else a negative error code.
1912  */
1913 int spi_register_master(struct spi_master *master)
1914 {
1915         static atomic_t         dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
1916         struct device           *dev = master->dev.parent;
1917         struct boardinfo        *bi;
1918         int                     status = -ENODEV;
1919         int                     dynamic = 0;
1920
1921         if (!dev)
1922                 return -ENODEV;
1923
1924         status = of_spi_register_master(master);
1925         if (status)
1926                 return status;
1927
1928         /* even if it's just one always-selected device, there must
1929          * be at least one chipselect
1930          */
1931         if (master->num_chipselect == 0)
1932                 return -EINVAL;
1933
1934         if ((master->bus_num < 0) && master->dev.of_node)
1935                 master->bus_num = of_alias_get_id(master->dev.of_node, "spi");
1936
1937         /* convention:  dynamically assigned bus IDs count down from the max */
1938         if (master->bus_num < 0) {
1939                 /* FIXME switch to an IDR based scheme, something like
1940                  * I2C now uses, so we can't run out of "dynamic" IDs
1941                  */
1942                 master->bus_num = atomic_dec_return(&dyn_bus_id);
1943                 dynamic = 1;
1944         }
1945
1946         INIT_LIST_HEAD(&master->queue);
1947         spin_lock_init(&master->queue_lock);
1948         spin_lock_init(&master->bus_lock_spinlock);
1949         mutex_init(&master->bus_lock_mutex);
1950         mutex_init(&master->io_mutex);
1951         master->bus_lock_flag = 0;
1952         init_completion(&master->xfer_completion);
1953         if (!master->max_dma_len)
1954                 master->max_dma_len = INT_MAX;
1955
1956         /* register the device, then userspace will see it.
1957          * registration fails if the bus ID is in use.
1958          */
1959         dev_set_name(&master->dev, "spi%u", master->bus_num);
1960         status = device_add(&master->dev);
1961         if (status < 0)
1962                 goto done;
1963         dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1964                         dynamic ? " (dynamic)" : "");
1965
1966         /* If we're using a queued driver, start the queue */
1967         if (master->transfer)
1968                 dev_info(dev, "master is unqueued, this is deprecated\n");
1969         else {
1970                 status = spi_master_initialize_queue(master);
1971                 if (status) {
1972                         device_del(&master->dev);
1973                         goto done;
1974                 }
1975         }
1976         /* add statistics */
1977         spin_lock_init(&master->statistics.lock);
1978
1979         mutex_lock(&board_lock);
1980         list_add_tail(&master->list, &spi_master_list);
1981         list_for_each_entry(bi, &board_list, list)
1982                 spi_match_master_to_boardinfo(master, &bi->board_info);
1983         mutex_unlock(&board_lock);
1984
1985         /* Register devices from the device tree and ACPI */
1986         of_register_spi_devices(master);
1987         acpi_register_spi_devices(master);
1988 done:
1989         return status;
1990 }
1991 EXPORT_SYMBOL_GPL(spi_register_master);
1992
1993 static void devm_spi_unregister(struct device *dev, void *res)
1994 {
1995         spi_unregister_master(*(struct spi_master **)res);
1996 }
1997
1998 /**
1999  * dev_spi_register_master - register managed SPI master controller
2000  * @dev:    device managing SPI master
2001  * @master: initialized master, originally from spi_alloc_master()
2002  * Context: can sleep
2003  *
2004  * Register a SPI device as with spi_register_master() which will
2005  * automatically be unregister
2006  *
2007  * Return: zero on success, else a negative error code.
2008  */
2009 int devm_spi_register_master(struct device *dev, struct spi_master *master)
2010 {
2011         struct spi_master **ptr;
2012         int ret;
2013
2014         ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
2015         if (!ptr)
2016                 return -ENOMEM;
2017
2018         ret = spi_register_master(master);
2019         if (!ret) {
2020                 *ptr = master;
2021                 devres_add(dev, ptr);
2022         } else {
2023                 devres_free(ptr);
2024         }
2025
2026         return ret;
2027 }
2028 EXPORT_SYMBOL_GPL(devm_spi_register_master);
2029
2030 static int __unregister(struct device *dev, void *null)
2031 {
2032         spi_unregister_device(to_spi_device(dev));
2033         return 0;
2034 }
2035
2036 /**
2037  * spi_unregister_master - unregister SPI master controller
2038  * @master: the master being unregistered
2039  * Context: can sleep
2040  *
2041  * This call is used only by SPI master controller drivers, which are the
2042  * only ones directly touching chip registers.
2043  *
2044  * This must be called from context that can sleep.
2045  */
2046 void spi_unregister_master(struct spi_master *master)
2047 {
2048         int dummy;
2049
2050         if (master->queued) {
2051                 if (spi_destroy_queue(master))
2052                         dev_err(&master->dev, "queue remove failed\n");
2053         }
2054
2055         mutex_lock(&board_lock);
2056         list_del(&master->list);
2057         mutex_unlock(&board_lock);
2058
2059         dummy = device_for_each_child(&master->dev, NULL, __unregister);
2060         device_unregister(&master->dev);
2061 }
2062 EXPORT_SYMBOL_GPL(spi_unregister_master);
2063
2064 int spi_master_suspend(struct spi_master *master)
2065 {
2066         int ret;
2067
2068         /* Basically no-ops for non-queued masters */
2069         if (!master->queued)
2070                 return 0;
2071
2072         ret = spi_stop_queue(master);
2073         if (ret)
2074                 dev_err(&master->dev, "queue stop failed\n");
2075
2076         return ret;
2077 }
2078 EXPORT_SYMBOL_GPL(spi_master_suspend);
2079
2080 int spi_master_resume(struct spi_master *master)
2081 {
2082         int ret;
2083
2084         if (!master->queued)
2085                 return 0;
2086
2087         ret = spi_start_queue(master);
2088         if (ret)
2089                 dev_err(&master->dev, "queue restart failed\n");
2090
2091         return ret;
2092 }
2093 EXPORT_SYMBOL_GPL(spi_master_resume);
2094
2095 static int __spi_master_match(struct device *dev, const void *data)
2096 {
2097         struct spi_master *m;
2098         const u16 *bus_num = data;
2099
2100         m = container_of(dev, struct spi_master, dev);
2101         return m->bus_num == *bus_num;
2102 }
2103
2104 /**
2105  * spi_busnum_to_master - look up master associated with bus_num
2106  * @bus_num: the master's bus number
2107  * Context: can sleep
2108  *
2109  * This call may be used with devices that are registered after
2110  * arch init time.  It returns a refcounted pointer to the relevant
2111  * spi_master (which the caller must release), or NULL if there is
2112  * no such master registered.
2113  *
2114  * Return: the SPI master structure on success, else NULL.
2115  */
2116 struct spi_master *spi_busnum_to_master(u16 bus_num)
2117 {
2118         struct device           *dev;
2119         struct spi_master       *master = NULL;
2120
2121         dev = class_find_device(&spi_master_class, NULL, &bus_num,
2122                                 __spi_master_match);
2123         if (dev)
2124                 master = container_of(dev, struct spi_master, dev);
2125         /* reference got in class_find_device */
2126         return master;
2127 }
2128 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
2129
2130 /*-------------------------------------------------------------------------*/
2131
2132 /* Core methods for SPI resource management */
2133
2134 /**
2135  * spi_res_alloc - allocate a spi resource that is life-cycle managed
2136  *                 during the processing of a spi_message while using
2137  *                 spi_transfer_one
2138  * @spi:     the spi device for which we allocate memory
2139  * @release: the release code to execute for this resource
2140  * @size:    size to alloc and return
2141  * @gfp:     GFP allocation flags
2142  *
2143  * Return: the pointer to the allocated data
2144  *
2145  * This may get enhanced in the future to allocate from a memory pool
2146  * of the @spi_device or @spi_master to avoid repeated allocations.
2147  */
2148 void *spi_res_alloc(struct spi_device *spi,
2149                     spi_res_release_t release,
2150                     size_t size, gfp_t gfp)
2151 {
2152         struct spi_res *sres;
2153
2154         sres = kzalloc(sizeof(*sres) + size, gfp);
2155         if (!sres)
2156                 return NULL;
2157
2158         INIT_LIST_HEAD(&sres->entry);
2159         sres->release = release;
2160
2161         return sres->data;
2162 }
2163 EXPORT_SYMBOL_GPL(spi_res_alloc);
2164
2165 /**
2166  * spi_res_free - free an spi resource
2167  * @res: pointer to the custom data of a resource
2168  *
2169  */
2170 void spi_res_free(void *res)
2171 {
2172         struct spi_res *sres = container_of(res, struct spi_res, data);
2173
2174         if (!res)
2175                 return;
2176
2177         WARN_ON(!list_empty(&sres->entry));
2178         kfree(sres);
2179 }
2180 EXPORT_SYMBOL_GPL(spi_res_free);
2181
2182 /**
2183  * spi_res_add - add a spi_res to the spi_message
2184  * @message: the spi message
2185  * @res:     the spi_resource
2186  */
2187 void spi_res_add(struct spi_message *message, void *res)
2188 {
2189         struct spi_res *sres = container_of(res, struct spi_res, data);
2190
2191         WARN_ON(!list_empty(&sres->entry));
2192         list_add_tail(&sres->entry, &message->resources);
2193 }
2194 EXPORT_SYMBOL_GPL(spi_res_add);
2195
2196 /**
2197  * spi_res_release - release all spi resources for this message
2198  * @master:  the @spi_master
2199  * @message: the @spi_message
2200  */
2201 void spi_res_release(struct spi_master *master,
2202                      struct spi_message *message)
2203 {
2204         struct spi_res *res;
2205
2206         while (!list_empty(&message->resources)) {
2207                 res = list_last_entry(&message->resources,
2208                                       struct spi_res, entry);
2209
2210                 if (res->release)
2211                         res->release(master, message, res->data);
2212
2213                 list_del(&res->entry);
2214
2215                 kfree(res);
2216         }
2217 }
2218 EXPORT_SYMBOL_GPL(spi_res_release);
2219
2220 /*-------------------------------------------------------------------------*/
2221
2222 /* Core methods for spi_message alterations */
2223
2224 static void __spi_replace_transfers_release(struct spi_master *master,
2225                                             struct spi_message *msg,
2226                                             void *res)
2227 {
2228         struct spi_replaced_transfers *rxfer = res;
2229         size_t i;
2230
2231         /* call extra callback if requested */
2232         if (rxfer->release)
2233                 rxfer->release(master, msg, res);
2234
2235         /* insert replaced transfers back into the message */
2236         list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
2237
2238         /* remove the formerly inserted entries */
2239         for (i = 0; i < rxfer->inserted; i++)
2240                 list_del(&rxfer->inserted_transfers[i].transfer_list);
2241 }
2242
2243 /**
2244  * spi_replace_transfers - replace transfers with several transfers
2245  *                         and register change with spi_message.resources
2246  * @msg:           the spi_message we work upon
2247  * @xfer_first:    the first spi_transfer we want to replace
2248  * @remove:        number of transfers to remove
2249  * @insert:        the number of transfers we want to insert instead
2250  * @release:       extra release code necessary in some circumstances
2251  * @extradatasize: extra data to allocate (with alignment guarantees
2252  *                 of struct @spi_transfer)
2253  * @gfp:           gfp flags
2254  *
2255  * Returns: pointer to @spi_replaced_transfers,
2256  *          PTR_ERR(...) in case of errors.
2257  */
2258 struct spi_replaced_transfers *spi_replace_transfers(
2259         struct spi_message *msg,
2260         struct spi_transfer *xfer_first,
2261         size_t remove,
2262         size_t insert,
2263         spi_replaced_release_t release,
2264         size_t extradatasize,
2265         gfp_t gfp)
2266 {
2267         struct spi_replaced_transfers *rxfer;
2268         struct spi_transfer *xfer;
2269         size_t i;
2270
2271         /* allocate the structure using spi_res */
2272         rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
2273                               insert * sizeof(struct spi_transfer)
2274                               + sizeof(struct spi_replaced_transfers)
2275                               + extradatasize,
2276                               gfp);
2277         if (!rxfer)
2278                 return ERR_PTR(-ENOMEM);
2279
2280         /* the release code to invoke before running the generic release */
2281         rxfer->release = release;
2282
2283         /* assign extradata */
2284         if (extradatasize)
2285                 rxfer->extradata =
2286                         &rxfer->inserted_transfers[insert];
2287
2288         /* init the replaced_transfers list */
2289         INIT_LIST_HEAD(&rxfer->replaced_transfers);
2290
2291         /* assign the list_entry after which we should reinsert
2292          * the @replaced_transfers - it may be spi_message.messages!
2293          */
2294         rxfer->replaced_after = xfer_first->transfer_list.prev;
2295
2296         /* remove the requested number of transfers */
2297         for (i = 0; i < remove; i++) {
2298                 /* if the entry after replaced_after it is msg->transfers
2299                  * then we have been requested to remove more transfers
2300                  * than are in the list
2301                  */
2302                 if (rxfer->replaced_after->next == &msg->transfers) {
2303                         dev_err(&msg->spi->dev,
2304                                 "requested to remove more spi_transfers than are available\n");
2305                         /* insert replaced transfers back into the message */
2306                         list_splice(&rxfer->replaced_transfers,
2307                                     rxfer->replaced_after);
2308
2309                         /* free the spi_replace_transfer structure */
2310                         spi_res_free(rxfer);
2311
2312                         /* and return with an error */
2313                         return ERR_PTR(-EINVAL);
2314                 }
2315
2316                 /* remove the entry after replaced_after from list of
2317                  * transfers and add it to list of replaced_transfers
2318                  */
2319                 list_move_tail(rxfer->replaced_after->next,
2320                                &rxfer->replaced_transfers);
2321         }
2322
2323         /* create copy of the given xfer with identical settings
2324          * based on the first transfer to get removed
2325          */
2326         for (i = 0; i < insert; i++) {
2327                 /* we need to run in reverse order */
2328                 xfer = &rxfer->inserted_transfers[insert - 1 - i];
2329
2330                 /* copy all spi_transfer data */
2331                 memcpy(xfer, xfer_first, sizeof(*xfer));
2332
2333                 /* add to list */
2334                 list_add(&xfer->transfer_list, rxfer->replaced_after);
2335
2336                 /* clear cs_change and delay_usecs for all but the last */
2337                 if (i) {
2338                         xfer->cs_change = false;
2339                         xfer->delay_usecs = 0;
2340                 }
2341         }
2342
2343         /* set up inserted */
2344         rxfer->inserted = insert;
2345
2346         /* and register it with spi_res/spi_message */
2347         spi_res_add(msg, rxfer);
2348
2349         return rxfer;
2350 }
2351 EXPORT_SYMBOL_GPL(spi_replace_transfers);
2352
2353 static int __spi_split_transfer_maxsize(struct spi_master *master,
2354                                         struct spi_message *msg,
2355                                         struct spi_transfer **xferp,
2356                                         size_t maxsize,
2357                                         gfp_t gfp)
2358 {
2359         struct spi_transfer *xfer = *xferp, *xfers;
2360         struct spi_replaced_transfers *srt;
2361         size_t offset;
2362         size_t count, i;
2363
2364         /* warn once about this fact that we are splitting a transfer */
2365         dev_warn_once(&msg->spi->dev,
2366                       "spi_transfer of length %i exceed max length of %zu - needed to split transfers\n",
2367                       xfer->len, maxsize);
2368
2369         /* calculate how many we have to replace */
2370         count = DIV_ROUND_UP(xfer->len, maxsize);
2371
2372         /* create replacement */
2373         srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
2374         if (IS_ERR(srt))
2375                 return PTR_ERR(srt);
2376         xfers = srt->inserted_transfers;
2377
2378         /* now handle each of those newly inserted spi_transfers
2379          * note that the replacements spi_transfers all are preset
2380          * to the same values as *xferp, so tx_buf, rx_buf and len
2381          * are all identical (as well as most others)
2382          * so we just have to fix up len and the pointers.
2383          *
2384          * this also includes support for the depreciated
2385          * spi_message.is_dma_mapped interface
2386          */
2387
2388         /* the first transfer just needs the length modified, so we
2389          * run it outside the loop
2390          */
2391         xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
2392
2393         /* all the others need rx_buf/tx_buf also set */
2394         for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
2395                 /* update rx_buf, tx_buf and dma */
2396                 if (xfers[i].rx_buf)
2397                         xfers[i].rx_buf += offset;
2398                 if (xfers[i].rx_dma)
2399                         xfers[i].rx_dma += offset;
2400                 if (xfers[i].tx_buf)
2401                         xfers[i].tx_buf += offset;
2402                 if (xfers[i].tx_dma)
2403                         xfers[i].tx_dma += offset;
2404
2405                 /* update length */
2406                 xfers[i].len = min(maxsize, xfers[i].len - offset);
2407         }
2408
2409         /* we set up xferp to the last entry we have inserted,
2410          * so that we skip those already split transfers
2411          */
2412         *xferp = &xfers[count - 1];
2413
2414         /* increment statistics counters */
2415         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics,
2416                                        transfers_split_maxsize);
2417         SPI_STATISTICS_INCREMENT_FIELD(&msg->spi->statistics,
2418                                        transfers_split_maxsize);
2419
2420         return 0;
2421 }
2422
2423 /**
2424  * spi_split_tranfers_maxsize - split spi transfers into multiple transfers
2425  *                              when an individual transfer exceeds a
2426  *                              certain size
2427  * @master:    the @spi_master for this transfer
2428  * @msg:   the @spi_message to transform
2429  * @maxsize:  the maximum when to apply this
2430  * @gfp: GFP allocation flags
2431  *
2432  * Return: status of transformation
2433  */
2434 int spi_split_transfers_maxsize(struct spi_master *master,
2435                                 struct spi_message *msg,
2436                                 size_t maxsize,
2437                                 gfp_t gfp)
2438 {
2439         struct spi_transfer *xfer;
2440         int ret;
2441
2442         /* iterate over the transfer_list,
2443          * but note that xfer is advanced to the last transfer inserted
2444          * to avoid checking sizes again unnecessarily (also xfer does
2445          * potentiall belong to a different list by the time the
2446          * replacement has happened
2447          */
2448         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
2449                 if (xfer->len > maxsize) {
2450                         ret = __spi_split_transfer_maxsize(
2451                                 master, msg, &xfer, maxsize, gfp);
2452                         if (ret)
2453                                 return ret;
2454                 }
2455         }
2456
2457         return 0;
2458 }
2459 EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
2460
2461 /*-------------------------------------------------------------------------*/
2462
2463 /* Core methods for SPI master protocol drivers.  Some of the
2464  * other core methods are currently defined as inline functions.
2465  */
2466
2467 static int __spi_validate_bits_per_word(struct spi_master *master, u8 bits_per_word)
2468 {
2469         if (master->bits_per_word_mask) {
2470                 /* Only 32 bits fit in the mask */
2471                 if (bits_per_word > 32)
2472                         return -EINVAL;
2473                 if (!(master->bits_per_word_mask &
2474                                 SPI_BPW_MASK(bits_per_word)))
2475                         return -EINVAL;
2476         }
2477
2478         return 0;
2479 }
2480
2481 /**
2482  * spi_setup - setup SPI mode and clock rate
2483  * @spi: the device whose settings are being modified
2484  * Context: can sleep, and no requests are queued to the device
2485  *
2486  * SPI protocol drivers may need to update the transfer mode if the
2487  * device doesn't work with its default.  They may likewise need
2488  * to update clock rates or word sizes from initial values.  This function
2489  * changes those settings, and must be called from a context that can sleep.
2490  * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
2491  * effect the next time the device is selected and data is transferred to
2492  * or from it.  When this function returns, the spi device is deselected.
2493  *
2494  * Note that this call will fail if the protocol driver specifies an option
2495  * that the underlying controller or its driver does not support.  For
2496  * example, not all hardware supports wire transfers using nine bit words,
2497  * LSB-first wire encoding, or active-high chipselects.
2498  *
2499  * Return: zero on success, else a negative error code.
2500  */
2501 int spi_setup(struct spi_device *spi)
2502 {
2503         unsigned        bad_bits, ugly_bits;
2504         int             status;
2505
2506         /* check mode to prevent that DUAL and QUAD set at the same time
2507          */
2508         if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
2509                 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
2510                 dev_err(&spi->dev,
2511                 "setup: can not select dual and quad at the same time\n");
2512                 return -EINVAL;
2513         }
2514         /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
2515          */
2516         if ((spi->mode & SPI_3WIRE) && (spi->mode &
2517                 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
2518                 return -EINVAL;
2519         /* help drivers fail *cleanly* when they need options
2520          * that aren't supported with their current master
2521          */
2522         bad_bits = spi->mode & ~spi->master->mode_bits;
2523         ugly_bits = bad_bits &
2524                     (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD);
2525         if (ugly_bits) {
2526                 dev_warn(&spi->dev,
2527                          "setup: ignoring unsupported mode bits %x\n",
2528                          ugly_bits);
2529                 spi->mode &= ~ugly_bits;
2530                 bad_bits &= ~ugly_bits;
2531         }
2532         if (bad_bits) {
2533                 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
2534                         bad_bits);
2535                 return -EINVAL;
2536         }
2537
2538         if (!spi->bits_per_word)
2539                 spi->bits_per_word = 8;
2540
2541         status = __spi_validate_bits_per_word(spi->master, spi->bits_per_word);
2542         if (status)
2543                 return status;
2544
2545         if (!spi->max_speed_hz)
2546                 spi->max_speed_hz = spi->master->max_speed_hz;
2547
2548         if (spi->master->setup)
2549                 status = spi->master->setup(spi);
2550
2551         spi_set_cs(spi, false);
2552
2553         dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
2554                         (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
2555                         (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
2556                         (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
2557                         (spi->mode & SPI_3WIRE) ? "3wire, " : "",
2558                         (spi->mode & SPI_LOOP) ? "loopback, " : "",
2559                         spi->bits_per_word, spi->max_speed_hz,
2560                         status);
2561
2562         return status;
2563 }
2564 EXPORT_SYMBOL_GPL(spi_setup);
2565
2566 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
2567 {
2568         struct spi_master *master = spi->master;
2569         struct spi_transfer *xfer;
2570         int w_size;
2571
2572         if (list_empty(&message->transfers))
2573                 return -EINVAL;
2574
2575         /* Half-duplex links include original MicroWire, and ones with
2576          * only one data pin like SPI_3WIRE (switches direction) or where
2577          * either MOSI or MISO is missing.  They can also be caused by
2578          * software limitations.
2579          */
2580         if ((master->flags & SPI_MASTER_HALF_DUPLEX)
2581                         || (spi->mode & SPI_3WIRE)) {
2582                 unsigned flags = master->flags;
2583
2584                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
2585                         if (xfer->rx_buf && xfer->tx_buf)
2586                                 return -EINVAL;
2587                         if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
2588                                 return -EINVAL;
2589                         if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
2590                                 return -EINVAL;
2591                 }
2592         }
2593
2594         /**
2595          * Set transfer bits_per_word and max speed as spi device default if
2596          * it is not set for this transfer.
2597          * Set transfer tx_nbits and rx_nbits as single transfer default
2598          * (SPI_NBITS_SINGLE) if it is not set for this transfer.
2599          */
2600         message->frame_length = 0;
2601         list_for_each_entry(xfer, &message->transfers, transfer_list) {
2602                 message->frame_length += xfer->len;
2603                 if (!xfer->bits_per_word)
2604                         xfer->bits_per_word = spi->bits_per_word;
2605
2606                 if (!xfer->speed_hz)
2607                         xfer->speed_hz = spi->max_speed_hz;
2608                 if (!xfer->speed_hz)
2609                         xfer->speed_hz = master->max_speed_hz;
2610
2611                 if (master->max_speed_hz &&
2612                     xfer->speed_hz > master->max_speed_hz)
2613                         xfer->speed_hz = master->max_speed_hz;
2614
2615                 if (__spi_validate_bits_per_word(master, xfer->bits_per_word))
2616                         return -EINVAL;
2617
2618                 /*
2619                  * SPI transfer length should be multiple of SPI word size
2620                  * where SPI word size should be power-of-two multiple
2621                  */
2622                 if (xfer->bits_per_word <= 8)
2623                         w_size = 1;
2624                 else if (xfer->bits_per_word <= 16)
2625                         w_size = 2;
2626                 else
2627                         w_size = 4;
2628
2629                 /* No partial transfers accepted */
2630                 if (xfer->len % w_size)
2631                         return -EINVAL;
2632
2633                 if (xfer->speed_hz && master->min_speed_hz &&
2634                     xfer->speed_hz < master->min_speed_hz)
2635                         return -EINVAL;
2636
2637                 if (xfer->tx_buf && !xfer->tx_nbits)
2638                         xfer->tx_nbits = SPI_NBITS_SINGLE;
2639                 if (xfer->rx_buf && !xfer->rx_nbits)
2640                         xfer->rx_nbits = SPI_NBITS_SINGLE;
2641                 /* check transfer tx/rx_nbits:
2642                  * 1. check the value matches one of single, dual and quad
2643                  * 2. check tx/rx_nbits match the mode in spi_device
2644                  */
2645                 if (xfer->tx_buf) {
2646                         if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
2647                                 xfer->tx_nbits != SPI_NBITS_DUAL &&
2648                                 xfer->tx_nbits != SPI_NBITS_QUAD)
2649                                 return -EINVAL;
2650                         if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
2651                                 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2652                                 return -EINVAL;
2653                         if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
2654                                 !(spi->mode & SPI_TX_QUAD))
2655                                 return -EINVAL;
2656                 }
2657                 /* check transfer rx_nbits */
2658                 if (xfer->rx_buf) {
2659                         if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
2660                                 xfer->rx_nbits != SPI_NBITS_DUAL &&
2661                                 xfer->rx_nbits != SPI_NBITS_QUAD)
2662                                 return -EINVAL;
2663                         if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
2664                                 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2665                                 return -EINVAL;
2666                         if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
2667                                 !(spi->mode & SPI_RX_QUAD))
2668                                 return -EINVAL;
2669                 }
2670         }
2671
2672         message->status = -EINPROGRESS;
2673
2674         return 0;
2675 }
2676
2677 static int __spi_async(struct spi_device *spi, struct spi_message *message)
2678 {
2679         struct spi_master *master = spi->master;
2680
2681         message->spi = spi;
2682
2683         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_async);
2684         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
2685
2686         trace_spi_message_submit(message);
2687
2688         return master->transfer(spi, message);
2689 }
2690
2691 /**
2692  * spi_async - asynchronous SPI transfer
2693  * @spi: device with which data will be exchanged
2694  * @message: describes the data transfers, including completion callback
2695  * Context: any (irqs may be blocked, etc)
2696  *
2697  * This call may be used in_irq and other contexts which can't sleep,
2698  * as well as from task contexts which can sleep.
2699  *
2700  * The completion callback is invoked in a context which can't sleep.
2701  * Before that invocation, the value of message->status is undefined.
2702  * When the callback is issued, message->status holds either zero (to
2703  * indicate complete success) or a negative error code.  After that
2704  * callback returns, the driver which issued the transfer request may
2705  * deallocate the associated memory; it's no longer in use by any SPI
2706  * core or controller driver code.
2707  *
2708  * Note that although all messages to a spi_device are handled in
2709  * FIFO order, messages may go to different devices in other orders.
2710  * Some device might be higher priority, or have various "hard" access
2711  * time requirements, for example.
2712  *
2713  * On detection of any fault during the transfer, processing of
2714  * the entire message is aborted, and the device is deselected.
2715  * Until returning from the associated message completion callback,
2716  * no other spi_message queued to that device will be processed.
2717  * (This rule applies equally to all the synchronous transfer calls,
2718  * which are wrappers around this core asynchronous primitive.)
2719  *
2720  * Return: zero on success, else a negative error code.
2721  */
2722 int spi_async(struct spi_device *spi, struct spi_message *message)
2723 {
2724         struct spi_master *master = spi->master;
2725         int ret;
2726         unsigned long flags;
2727
2728         ret = __spi_validate(spi, message);
2729         if (ret != 0)
2730                 return ret;
2731
2732         spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2733
2734         if (master->bus_lock_flag)
2735                 ret = -EBUSY;
2736         else
2737                 ret = __spi_async(spi, message);
2738
2739         spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2740
2741         return ret;
2742 }
2743 EXPORT_SYMBOL_GPL(spi_async);
2744
2745 /**
2746  * spi_async_locked - version of spi_async with exclusive bus usage
2747  * @spi: device with which data will be exchanged
2748  * @message: describes the data transfers, including completion callback
2749  * Context: any (irqs may be blocked, etc)
2750  *
2751  * This call may be used in_irq and other contexts which can't sleep,
2752  * as well as from task contexts which can sleep.
2753  *
2754  * The completion callback is invoked in a context which can't sleep.
2755  * Before that invocation, the value of message->status is undefined.
2756  * When the callback is issued, message->status holds either zero (to
2757  * indicate complete success) or a negative error code.  After that
2758  * callback returns, the driver which issued the transfer request may
2759  * deallocate the associated memory; it's no longer in use by any SPI
2760  * core or controller driver code.
2761  *
2762  * Note that although all messages to a spi_device are handled in
2763  * FIFO order, messages may go to different devices in other orders.
2764  * Some device might be higher priority, or have various "hard" access
2765  * time requirements, for example.
2766  *
2767  * On detection of any fault during the transfer, processing of
2768  * the entire message is aborted, and the device is deselected.
2769  * Until returning from the associated message completion callback,
2770  * no other spi_message queued to that device will be processed.
2771  * (This rule applies equally to all the synchronous transfer calls,
2772  * which are wrappers around this core asynchronous primitive.)
2773  *
2774  * Return: zero on success, else a negative error code.
2775  */
2776 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
2777 {
2778         struct spi_master *master = spi->master;
2779         int ret;
2780         unsigned long flags;
2781
2782         ret = __spi_validate(spi, message);
2783         if (ret != 0)
2784                 return ret;
2785
2786         spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2787
2788         ret = __spi_async(spi, message);
2789
2790         spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2791
2792         return ret;
2793
2794 }
2795 EXPORT_SYMBOL_GPL(spi_async_locked);
2796
2797
2798 int spi_flash_read(struct spi_device *spi,
2799                    struct spi_flash_read_message *msg)
2800
2801 {
2802         struct spi_master *master = spi->master;
2803         struct device *rx_dev = NULL;
2804         int ret;
2805
2806         if ((msg->opcode_nbits == SPI_NBITS_DUAL ||
2807              msg->addr_nbits == SPI_NBITS_DUAL) &&
2808             !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2809                 return -EINVAL;
2810         if ((msg->opcode_nbits == SPI_NBITS_QUAD ||
2811              msg->addr_nbits == SPI_NBITS_QUAD) &&
2812             !(spi->mode & SPI_TX_QUAD))
2813                 return -EINVAL;
2814         if (msg->data_nbits == SPI_NBITS_DUAL &&
2815             !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2816                 return -EINVAL;
2817         if (msg->data_nbits == SPI_NBITS_QUAD &&
2818             !(spi->mode &  SPI_RX_QUAD))
2819                 return -EINVAL;
2820
2821         if (master->auto_runtime_pm) {
2822                 ret = pm_runtime_get_sync(master->dev.parent);
2823                 if (ret < 0) {
2824                         dev_err(&master->dev, "Failed to power device: %d\n",
2825                                 ret);
2826                         return ret;
2827                 }
2828         }
2829
2830         mutex_lock(&master->bus_lock_mutex);
2831         mutex_lock(&master->io_mutex);
2832         if (master->dma_rx) {
2833                 rx_dev = master->dma_rx->device->dev;
2834                 ret = spi_map_buf(master, rx_dev, &msg->rx_sg,
2835                                   msg->buf, msg->len,
2836                                   DMA_FROM_DEVICE);
2837                 if (!ret)
2838                         msg->cur_msg_mapped = true;
2839         }
2840         ret = master->spi_flash_read(spi, msg);
2841         if (msg->cur_msg_mapped)
2842                 spi_unmap_buf(master, rx_dev, &msg->rx_sg,
2843                               DMA_FROM_DEVICE);
2844         mutex_unlock(&master->io_mutex);
2845         mutex_unlock(&master->bus_lock_mutex);
2846
2847         if (master->auto_runtime_pm)
2848                 pm_runtime_put(master->dev.parent);
2849
2850         return ret;
2851 }
2852 EXPORT_SYMBOL_GPL(spi_flash_read);
2853
2854 /*-------------------------------------------------------------------------*/
2855
2856 /* Utility methods for SPI master protocol drivers, layered on
2857  * top of the core.  Some other utility methods are defined as
2858  * inline functions.
2859  */
2860
2861 static void spi_complete(void *arg)
2862 {
2863         complete(arg);
2864 }
2865
2866 static int __spi_sync(struct spi_device *spi, struct spi_message *message)
2867 {
2868         DECLARE_COMPLETION_ONSTACK(done);
2869         int status;
2870         struct spi_master *master = spi->master;
2871         unsigned long flags;
2872
2873         status = __spi_validate(spi, message);
2874         if (status != 0)
2875                 return status;
2876
2877         message->complete = spi_complete;
2878         message->context = &done;
2879         message->spi = spi;
2880
2881         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_sync);
2882         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
2883
2884         /* If we're not using the legacy transfer method then we will
2885          * try to transfer in the calling context so special case.
2886          * This code would be less tricky if we could remove the
2887          * support for driver implemented message queues.
2888          */
2889         if (master->transfer == spi_queued_transfer) {
2890                 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2891
2892                 trace_spi_message_submit(message);
2893
2894                 status = __spi_queued_transfer(spi, message, false);
2895
2896                 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2897         } else {
2898                 status = spi_async_locked(spi, message);
2899         }
2900
2901         if (status == 0) {
2902                 /* Push out the messages in the calling context if we
2903                  * can.
2904                  */
2905                 if (master->transfer == spi_queued_transfer) {
2906                         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics,
2907                                                        spi_sync_immediate);
2908                         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
2909                                                        spi_sync_immediate);
2910                         __spi_pump_messages(master, false);
2911                 }
2912
2913                 wait_for_completion(&done);
2914                 status = message->status;
2915         }
2916         message->context = NULL;
2917         return status;
2918 }
2919
2920 /**
2921  * spi_sync - blocking/synchronous SPI data transfers
2922  * @spi: device with which data will be exchanged
2923  * @message: describes the data transfers
2924  * Context: can sleep
2925  *
2926  * This call may only be used from a context that may sleep.  The sleep
2927  * is non-interruptible, and has no timeout.  Low-overhead controller
2928  * drivers may DMA directly into and out of the message buffers.
2929  *
2930  * Note that the SPI device's chip select is active during the message,
2931  * and then is normally disabled between messages.  Drivers for some
2932  * frequently-used devices may want to minimize costs of selecting a chip,
2933  * by leaving it selected in anticipation that the next message will go
2934  * to the same chip.  (That may increase power usage.)
2935  *
2936  * Also, the caller is guaranteeing that the memory associated with the
2937  * message will not be freed before this call returns.
2938  *
2939  * Return: zero on success, else a negative error code.
2940  */
2941 int spi_sync(struct spi_device *spi, struct spi_message *message)
2942 {
2943         int ret;
2944
2945         mutex_lock(&spi->master->bus_lock_mutex);
2946         ret = __spi_sync(spi, message);
2947         mutex_unlock(&spi->master->bus_lock_mutex);
2948
2949         return ret;
2950 }
2951 EXPORT_SYMBOL_GPL(spi_sync);
2952
2953 /**
2954  * spi_sync_locked - version of spi_sync with exclusive bus usage
2955  * @spi: device with which data will be exchanged
2956  * @message: describes the data transfers
2957  * Context: can sleep
2958  *
2959  * This call may only be used from a context that may sleep.  The sleep
2960  * is non-interruptible, and has no timeout.  Low-overhead controller
2961  * drivers may DMA directly into and out of the message buffers.
2962  *
2963  * This call should be used by drivers that require exclusive access to the
2964  * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
2965  * be released by a spi_bus_unlock call when the exclusive access is over.
2966  *
2967  * Return: zero on success, else a negative error code.
2968  */
2969 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
2970 {
2971         return __spi_sync(spi, message);
2972 }
2973 EXPORT_SYMBOL_GPL(spi_sync_locked);
2974
2975 /**
2976  * spi_bus_lock - obtain a lock for exclusive SPI bus usage
2977  * @master: SPI bus master that should be locked for exclusive bus access
2978  * Context: can sleep
2979  *
2980  * This call may only be used from a context that may sleep.  The sleep
2981  * is non-interruptible, and has no timeout.
2982  *
2983  * This call should be used by drivers that require exclusive access to the
2984  * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
2985  * exclusive access is over. Data transfer must be done by spi_sync_locked
2986  * and spi_async_locked calls when the SPI bus lock is held.
2987  *
2988  * Return: always zero.
2989  */
2990 int spi_bus_lock(struct spi_master *master)
2991 {
2992         unsigned long flags;
2993
2994         mutex_lock(&master->bus_lock_mutex);
2995
2996         spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2997         master->bus_lock_flag = 1;
2998         spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2999
3000         /* mutex remains locked until spi_bus_unlock is called */
3001
3002         return 0;
3003 }
3004 EXPORT_SYMBOL_GPL(spi_bus_lock);
3005
3006 /**
3007  * spi_bus_unlock - release the lock for exclusive SPI bus usage
3008  * @master: SPI bus master that was locked for exclusive bus access
3009  * Context: can sleep
3010  *
3011  * This call may only be used from a context that may sleep.  The sleep
3012  * is non-interruptible, and has no timeout.
3013  *
3014  * This call releases an SPI bus lock previously obtained by an spi_bus_lock
3015  * call.
3016  *
3017  * Return: always zero.
3018  */
3019 int spi_bus_unlock(struct spi_master *master)
3020 {
3021         master->bus_lock_flag = 0;
3022
3023         mutex_unlock(&master->bus_lock_mutex);
3024
3025         return 0;
3026 }
3027 EXPORT_SYMBOL_GPL(spi_bus_unlock);
3028
3029 /* portable code must never pass more than 32 bytes */
3030 #define SPI_BUFSIZ      max(32, SMP_CACHE_BYTES)
3031
3032 static u8       *buf;
3033
3034 /**
3035  * spi_write_then_read - SPI synchronous write followed by read
3036  * @spi: device with which data will be exchanged
3037  * @txbuf: data to be written (need not be dma-safe)
3038  * @n_tx: size of txbuf, in bytes
3039  * @rxbuf: buffer into which data will be read (need not be dma-safe)
3040  * @n_rx: size of rxbuf, in bytes
3041  * Context: can sleep
3042  *
3043  * This performs a half duplex MicroWire style transaction with the
3044  * device, sending txbuf and then reading rxbuf.  The return value
3045  * is zero for success, else a negative errno status code.
3046  * This call may only be used from a context that may sleep.
3047  *
3048  * Parameters to this routine are always copied using a small buffer;
3049  * portable code should never use this for more than 32 bytes.
3050  * Performance-sensitive or bulk transfer code should instead use
3051  * spi_{async,sync}() calls with dma-safe buffers.
3052  *
3053  * Return: zero on success, else a negative error code.
3054  */
3055 int spi_write_then_read(struct spi_device *spi,
3056                 const void *txbuf, unsigned n_tx,
3057                 void *rxbuf, unsigned n_rx)
3058 {
3059         static DEFINE_MUTEX(lock);
3060
3061         int                     status;
3062         struct spi_message      message;
3063         struct spi_transfer     x[2];
3064         u8                      *local_buf;
3065
3066         /* Use preallocated DMA-safe buffer if we can.  We can't avoid
3067          * copying here, (as a pure convenience thing), but we can
3068          * keep heap costs out of the hot path unless someone else is
3069          * using the pre-allocated buffer or the transfer is too large.
3070          */
3071         if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
3072                 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
3073                                     GFP_KERNEL | GFP_DMA);
3074                 if (!local_buf)
3075                         return -ENOMEM;
3076         } else {
3077                 local_buf = buf;
3078         }
3079
3080         spi_message_init(&message);
3081         memset(x, 0, sizeof(x));
3082         if (n_tx) {
3083                 x[0].len = n_tx;
3084                 spi_message_add_tail(&x[0], &message);
3085         }
3086         if (n_rx) {
3087                 x[1].len = n_rx;
3088                 spi_message_add_tail(&x[1], &message);
3089         }
3090
3091         memcpy(local_buf, txbuf, n_tx);
3092         x[0].tx_buf = local_buf;
3093         x[1].rx_buf = local_buf + n_tx;
3094
3095         /* do the i/o */
3096         status = spi_sync(spi, &message);
3097         if (status == 0)
3098                 memcpy(rxbuf, x[1].rx_buf, n_rx);
3099
3100         if (x[0].tx_buf == buf)
3101                 mutex_unlock(&lock);
3102         else
3103                 kfree(local_buf);
3104
3105         return status;
3106 }
3107 EXPORT_SYMBOL_GPL(spi_write_then_read);
3108
3109 /*-------------------------------------------------------------------------*/
3110
3111 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
3112 static int __spi_of_device_match(struct device *dev, void *data)
3113 {
3114         return dev->of_node == data;
3115 }
3116
3117 /* must call put_device() when done with returned spi_device device */
3118 static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
3119 {
3120         struct device *dev = bus_find_device(&spi_bus_type, NULL, node,
3121                                                 __spi_of_device_match);
3122         return dev ? to_spi_device(dev) : NULL;
3123 }
3124
3125 static int __spi_of_master_match(struct device *dev, const void *data)
3126 {
3127         return dev->of_node == data;
3128 }
3129
3130 /* the spi masters are not using spi_bus, so we find it with another way */
3131 static struct spi_master *of_find_spi_master_by_node(struct device_node *node)
3132 {
3133         struct device *dev;
3134
3135         dev = class_find_device(&spi_master_class, NULL, node,
3136                                 __spi_of_master_match);
3137         if (!dev)
3138                 return NULL;
3139
3140         /* reference got in class_find_device */
3141         return container_of(dev, struct spi_master, dev);
3142 }
3143
3144 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
3145                          void *arg)
3146 {
3147         struct of_reconfig_data *rd = arg;
3148         struct spi_master *master;
3149         struct spi_device *spi;
3150
3151         switch (of_reconfig_get_state_change(action, arg)) {
3152         case OF_RECONFIG_CHANGE_ADD:
3153                 master = of_find_spi_master_by_node(rd->dn->parent);
3154                 if (master == NULL)
3155                         return NOTIFY_OK;       /* not for us */
3156
3157                 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
3158                         put_device(&master->dev);
3159                         return NOTIFY_OK;
3160                 }
3161
3162                 spi = of_register_spi_device(master, rd->dn);
3163                 put_device(&master->dev);
3164
3165                 if (IS_ERR(spi)) {
3166                         pr_err("%s: failed to create for '%s'\n",
3167                                         __func__, rd->dn->full_name);
3168                         of_node_clear_flag(rd->dn, OF_POPULATED);
3169                         return notifier_from_errno(PTR_ERR(spi));
3170                 }
3171                 break;
3172
3173         case OF_RECONFIG_CHANGE_REMOVE:
3174                 /* already depopulated? */
3175                 if (!of_node_check_flag(rd->dn, OF_POPULATED))
3176                         return NOTIFY_OK;
3177
3178                 /* find our device by node */
3179                 spi = of_find_spi_device_by_node(rd->dn);
3180                 if (spi == NULL)
3181                         return NOTIFY_OK;       /* no? not meant for us */
3182
3183                 /* unregister takes one ref away */
3184                 spi_unregister_device(spi);
3185
3186                 /* and put the reference of the find */
3187                 put_device(&spi->dev);
3188                 break;
3189         }
3190
3191         return NOTIFY_OK;
3192 }
3193
3194 static struct notifier_block spi_of_notifier = {
3195         .notifier_call = of_spi_notify,
3196 };
3197 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3198 extern struct notifier_block spi_of_notifier;
3199 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3200
3201 #if IS_ENABLED(CONFIG_ACPI)
3202 static int spi_acpi_master_match(struct device *dev, const void *data)
3203 {
3204         return ACPI_COMPANION(dev->parent) == data;
3205 }
3206
3207 static int spi_acpi_device_match(struct device *dev, void *data)
3208 {
3209         return ACPI_COMPANION(dev) == data;
3210 }
3211
3212 static struct spi_master *acpi_spi_find_master_by_adev(struct acpi_device *adev)
3213 {
3214         struct device *dev;
3215
3216         dev = class_find_device(&spi_master_class, NULL, adev,
3217                                 spi_acpi_master_match);
3218         if (!dev)
3219                 return NULL;
3220
3221         return container_of(dev, struct spi_master, dev);
3222 }
3223
3224 static struct spi_device *acpi_spi_find_device_by_adev(struct acpi_device *adev)
3225 {
3226         struct device *dev;
3227
3228         dev = bus_find_device(&spi_bus_type, NULL, adev, spi_acpi_device_match);
3229
3230         return dev ? to_spi_device(dev) : NULL;
3231 }
3232
3233 static int acpi_spi_notify(struct notifier_block *nb, unsigned long value,
3234                            void *arg)
3235 {
3236         struct acpi_device *adev = arg;
3237         struct spi_master *master;
3238         struct spi_device *spi;
3239
3240         switch (value) {
3241         case ACPI_RECONFIG_DEVICE_ADD:
3242                 master = acpi_spi_find_master_by_adev(adev->parent);
3243                 if (!master)
3244                         break;
3245
3246                 acpi_register_spi_device(master, adev);
3247                 put_device(&master->dev);
3248                 break;
3249         case ACPI_RECONFIG_DEVICE_REMOVE:
3250                 if (!acpi_device_enumerated(adev))
3251                         break;
3252
3253                 spi = acpi_spi_find_device_by_adev(adev);
3254                 if (!spi)
3255                         break;
3256
3257                 spi_unregister_device(spi);
3258                 put_device(&spi->dev);
3259                 break;
3260         }
3261
3262         return NOTIFY_OK;
3263 }
3264
3265 static struct notifier_block spi_acpi_notifier = {
3266         .notifier_call = acpi_spi_notify,
3267 };
3268 #else
3269 extern struct notifier_block spi_acpi_notifier;
3270 #endif
3271
3272 static int __init spi_init(void)
3273 {
3274         int     status;
3275
3276         buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
3277         if (!buf) {
3278                 status = -ENOMEM;
3279                 goto err0;
3280         }
3281
3282         status = bus_register(&spi_bus_type);
3283         if (status < 0)
3284                 goto err1;
3285
3286         status = class_register(&spi_master_class);
3287         if (status < 0)
3288                 goto err2;
3289
3290         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
3291                 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
3292         if (IS_ENABLED(CONFIG_ACPI))
3293                 WARN_ON(acpi_reconfig_notifier_register(&spi_acpi_notifier));
3294
3295         return 0;
3296
3297 err2:
3298         bus_unregister(&spi_bus_type);
3299 err1:
3300         kfree(buf);
3301         buf = NULL;
3302 err0:
3303         return status;
3304 }
3305
3306 /* board_info is normally registered in arch_initcall(),
3307  * but even essential drivers wait till later
3308  *
3309  * REVISIT only boardinfo really needs static linking. the rest (device and
3310  * driver registration) _could_ be dynamically linked (modular) ... costs
3311  * include needing to have boardinfo data structures be much more public.
3312  */
3313 postcore_initcall(spi_init);
3314