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