spi.c 63.2 KB
Newer Older
1
/*
G
Grant Likely 已提交
2
 * SPI init/core code
3 4
 *
 * Copyright (C) 2005 David Brownell
5
 * Copyright (C) 2008 Secret Lab Technologies Ltd.
6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/cache.h>
22 23
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
24
#include <linux/mutex.h>
25
#include <linux/of_device.h>
26
#include <linux/of_irq.h>
27
#include <linux/clk/clk-conf.h>
28
#include <linux/slab.h>
29
#include <linux/mod_devicetable.h>
30
#include <linux/spi/spi.h>
31
#include <linux/of_gpio.h>
M
Mark Brown 已提交
32
#include <linux/pm_runtime.h>
33
#include <linux/pm_domain.h>
34
#include <linux/export.h>
35
#include <linux/sched/rt.h>
36 37
#include <linux/delay.h>
#include <linux/kthread.h>
38 39
#include <linux/ioport.h>
#include <linux/acpi.h>
40

41 42 43
#define CREATE_TRACE_POINTS
#include <trace/events/spi.h>

44 45
static void spidev_release(struct device *dev)
{
46
	struct spi_device	*spi = to_spi_device(dev);
47 48 49 50 51

	/* spi masters may cleanup for released devices */
	if (spi->master->cleanup)
		spi->master->cleanup(spi);

D
David Brownell 已提交
52
	spi_master_put(spi->master);
53
	kfree(spi);
54 55 56 57 58 59
}

static ssize_t
modalias_show(struct device *dev, struct device_attribute *a, char *buf)
{
	const struct spi_device	*spi = to_spi_device(dev);
60 61 62 63 64
	int len;

	len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
	if (len != -ENODEV)
		return len;
65

66
	return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
67
}
68
static DEVICE_ATTR_RO(modalias);
69

70 71 72
static struct attribute *spi_dev_attrs[] = {
	&dev_attr_modalias.attr,
	NULL,
73
};
74
ATTRIBUTE_GROUPS(spi_dev);
75 76 77 78 79

/* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
 * and the sysfs version makes coldplug work too.
 */

80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98
static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
						const struct spi_device *sdev)
{
	while (id->name[0]) {
		if (!strcmp(sdev->modalias, id->name))
			return id;
		id++;
	}
	return NULL;
}

const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
{
	const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);

	return spi_match_id(sdrv->id_table, sdev);
}
EXPORT_SYMBOL_GPL(spi_get_device_id);

99 100 101
static int spi_match_device(struct device *dev, struct device_driver *drv)
{
	const struct spi_device	*spi = to_spi_device(dev);
102 103
	const struct spi_driver	*sdrv = to_spi_driver(drv);

104 105 106 107
	/* Attempt an OF style match */
	if (of_driver_match_device(dev, drv))
		return 1;

108 109 110 111
	/* Then try ACPI */
	if (acpi_driver_match_device(dev, drv))
		return 1;

112 113
	if (sdrv->id_table)
		return !!spi_match_id(sdrv->id_table, spi);
114

115
	return strcmp(spi->modalias, drv->name) == 0;
116 117
}

118
static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
119 120
{
	const struct spi_device		*spi = to_spi_device(dev);
121 122 123 124 125
	int rc;

	rc = acpi_device_uevent_modalias(dev, env);
	if (rc != -ENODEV)
		return rc;
126

127
	add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
128 129 130 131 132
	return 0;
}

struct bus_type spi_bus_type = {
	.name		= "spi",
133
	.dev_groups	= spi_dev_groups,
134 135 136 137 138
	.match		= spi_match_device,
	.uevent		= spi_uevent,
};
EXPORT_SYMBOL_GPL(spi_bus_type);

139 140 141 142

static int spi_drv_probe(struct device *dev)
{
	const struct spi_driver		*sdrv = to_spi_driver(dev->driver);
143 144
	int ret;

145 146 147 148
	ret = of_clk_set_defaults(dev->of_node, false);
	if (ret)
		return ret;

149 150 151 152 153 154
	ret = dev_pm_domain_attach(dev, true);
	if (ret != -EPROBE_DEFER) {
		ret = sdrv->probe(to_spi_device(dev));
		if (ret)
			dev_pm_domain_detach(dev, true);
	}
155

156
	return ret;
157 158 159 160 161
}

static int spi_drv_remove(struct device *dev)
{
	const struct spi_driver		*sdrv = to_spi_driver(dev->driver);
162 163
	int ret;

164
	ret = sdrv->remove(to_spi_device(dev));
165
	dev_pm_domain_detach(dev, true);
166

167
	return ret;
168 169 170 171 172 173 174 175 176
}

static void spi_drv_shutdown(struct device *dev)
{
	const struct spi_driver		*sdrv = to_spi_driver(dev->driver);

	sdrv->shutdown(to_spi_device(dev));
}

D
David Brownell 已提交
177 178 179 180 181
/**
 * spi_register_driver - register a SPI driver
 * @sdrv: the driver to register
 * Context: can sleep
 */
182 183 184 185 186 187 188 189 190 191 192 193 194
int spi_register_driver(struct spi_driver *sdrv)
{
	sdrv->driver.bus = &spi_bus_type;
	if (sdrv->probe)
		sdrv->driver.probe = spi_drv_probe;
	if (sdrv->remove)
		sdrv->driver.remove = spi_drv_remove;
	if (sdrv->shutdown)
		sdrv->driver.shutdown = spi_drv_shutdown;
	return driver_register(&sdrv->driver);
}
EXPORT_SYMBOL_GPL(spi_register_driver);

195 196 197 198 199 200 201 202 203 204
/*-------------------------------------------------------------------------*/

/* SPI devices should normally not be created by SPI device drivers; that
 * would make them board-specific.  Similarly with SPI master drivers.
 * Device registration normally goes into like arch/.../mach.../board-YYY.c
 * with other readonly (flashable) information about mainboard devices.
 */

struct boardinfo {
	struct list_head	list;
205
	struct spi_board_info	board_info;
206 207 208
};

static LIST_HEAD(board_list);
209 210 211 212 213 214
static LIST_HEAD(spi_master_list);

/*
 * Used to protect add/del opertion for board_info list and
 * spi_master list, and their matching process
 */
215
static DEFINE_MUTEX(board_lock);
216

217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240
/**
 * spi_alloc_device - Allocate a new SPI device
 * @master: Controller to which device is connected
 * Context: can sleep
 *
 * Allows a driver to allocate and initialize a spi_device without
 * registering it immediately.  This allows a driver to directly
 * fill the spi_device with device parameters before calling
 * spi_add_device() on it.
 *
 * Caller is responsible to call spi_add_device() on the returned
 * spi_device structure to add it to the SPI master.  If the caller
 * needs to discard the spi_device without adding it, then it should
 * call spi_dev_put() on it.
 *
 * Returns a pointer to the new device, or NULL.
 */
struct spi_device *spi_alloc_device(struct spi_master *master)
{
	struct spi_device	*spi;

	if (!spi_master_get(master))
		return NULL;

J
Jingoo Han 已提交
241
	spi = kzalloc(sizeof(*spi), GFP_KERNEL);
242 243 244 245 246 247
	if (!spi) {
		spi_master_put(master);
		return NULL;
	}

	spi->master = master;
248
	spi->dev.parent = &master->dev;
249 250
	spi->dev.bus = &spi_bus_type;
	spi->dev.release = spidev_release;
251
	spi->cs_gpio = -ENOENT;
252 253 254 255 256
	device_initialize(&spi->dev);
	return spi;
}
EXPORT_SYMBOL_GPL(spi_alloc_device);

257 258 259 260 261 262 263 264 265 266 267 268 269
static void spi_dev_set_name(struct spi_device *spi)
{
	struct acpi_device *adev = ACPI_COMPANION(&spi->dev);

	if (adev) {
		dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
		return;
	}

	dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
		     spi->chip_select);
}

270 271 272 273 274 275 276 277 278 279 280
static int spi_dev_check(struct device *dev, void *data)
{
	struct spi_device *spi = to_spi_device(dev);
	struct spi_device *new_spi = data;

	if (spi->master == new_spi->master &&
	    spi->chip_select == new_spi->chip_select)
		return -EBUSY;
	return 0;
}

281 282 283 284 285 286 287
/**
 * spi_add_device - Add spi_device allocated with spi_alloc_device
 * @spi: spi_device to register
 *
 * Companion function to spi_alloc_device.  Devices allocated with
 * spi_alloc_device can be added onto the spi bus with this function.
 *
288
 * Returns 0 on success; negative errno on failure
289 290 291
 */
int spi_add_device(struct spi_device *spi)
{
292
	static DEFINE_MUTEX(spi_add_lock);
293 294
	struct spi_master *master = spi->master;
	struct device *dev = master->dev.parent;
295 296 297
	int status;

	/* Chipselects are numbered 0..max; validate. */
298
	if (spi->chip_select >= master->num_chipselect) {
299 300
		dev_err(dev, "cs%d >= max %d\n",
			spi->chip_select,
301
			master->num_chipselect);
302 303 304 305
		return -EINVAL;
	}

	/* Set the bus ID string */
306
	spi_dev_set_name(spi);
307 308 309 310 311 312 313

	/* We need to make sure there's no other device with this
	 * chipselect **BEFORE** we call setup(), else we'll trash
	 * its configuration.  Lock against concurrent add() calls.
	 */
	mutex_lock(&spi_add_lock);

314 315
	status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
	if (status) {
316 317 318 319 320
		dev_err(dev, "chipselect %d already in use\n",
				spi->chip_select);
		goto done;
	}

321 322 323
	if (master->cs_gpios)
		spi->cs_gpio = master->cs_gpios[spi->chip_select];

324 325 326 327
	/* Drivers may modify this initial i/o setup, but will
	 * normally rely on the device being setup.  Devices
	 * using SPI_CS_HIGH can't coexist well otherwise...
	 */
328
	status = spi_setup(spi);
329
	if (status < 0) {
330 331
		dev_err(dev, "can't setup %s, status %d\n",
				dev_name(&spi->dev), status);
332
		goto done;
333 334
	}

335
	/* Device may be bound to an active driver when this returns */
336
	status = device_add(&spi->dev);
337
	if (status < 0)
338 339
		dev_err(dev, "can't add %s, status %d\n",
				dev_name(&spi->dev), status);
340
	else
341
		dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
342

343 344 345
done:
	mutex_unlock(&spi_add_lock);
	return status;
346 347
}
EXPORT_SYMBOL_GPL(spi_add_device);
348

D
David Brownell 已提交
349 350 351 352 353 354 355
/**
 * spi_new_device - instantiate one new SPI device
 * @master: Controller to which device is connected
 * @chip: Describes the SPI device
 * Context: can sleep
 *
 * On typical mainboards, this is purely internal; and it's not needed
356 357 358 359
 * after board init creates the hard-wired devices.  Some development
 * platforms may not be able to use spi_register_board_info though, and
 * this is exported so that for example a USB or parport based adapter
 * driver could add devices (which it would learn about out-of-band).
360 361
 *
 * Returns the new device, or NULL.
362
 */
363 364
struct spi_device *spi_new_device(struct spi_master *master,
				  struct spi_board_info *chip)
365 366 367 368
{
	struct spi_device	*proxy;
	int			status;

369 370 371 372 373 374 375
	/* NOTE:  caller did any chip->bus_num checks necessary.
	 *
	 * Also, unless we change the return value convention to use
	 * error-or-pointer (not NULL-or-pointer), troubleshootability
	 * suggests syslogged diagnostics are best here (ugh).
	 */

376 377
	proxy = spi_alloc_device(master);
	if (!proxy)
378 379
		return NULL;

380 381
	WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));

382 383
	proxy->chip_select = chip->chip_select;
	proxy->max_speed_hz = chip->max_speed_hz;
384
	proxy->mode = chip->mode;
385
	proxy->irq = chip->irq;
386
	strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
387 388 389 390
	proxy->dev.platform_data = (void *) chip->platform_data;
	proxy->controller_data = chip->controller_data;
	proxy->controller_state = NULL;

391
	status = spi_add_device(proxy);
392
	if (status < 0) {
393 394
		spi_dev_put(proxy);
		return NULL;
395 396 397 398 399 400
	}

	return proxy;
}
EXPORT_SYMBOL_GPL(spi_new_device);

401 402 403 404 405 406 407 408 409 410 411 412 413 414
static void spi_match_master_to_boardinfo(struct spi_master *master,
				struct spi_board_info *bi)
{
	struct spi_device *dev;

	if (master->bus_num != bi->bus_num)
		return;

	dev = spi_new_device(master, bi);
	if (!dev)
		dev_err(master->dev.parent, "can't create new device for %s\n",
			bi->modalias);
}

D
David Brownell 已提交
415 416 417 418 419 420
/**
 * spi_register_board_info - register SPI devices for a given board
 * @info: array of chip descriptors
 * @n: how many descriptors are provided
 * Context: can sleep
 *
421 422 423 424 425 426 427 428 429 430 431 432 433
 * Board-specific early init code calls this (probably during arch_initcall)
 * with segments of the SPI device table.  Any device nodes are created later,
 * after the relevant parent SPI controller (bus_num) is defined.  We keep
 * this table of devices forever, so that reloading a controller driver will
 * not make Linux forget about these hard-wired devices.
 *
 * Other code can also call this, e.g. a particular add-on board might provide
 * SPI devices through its expansion connector, so code initializing that board
 * would naturally declare its SPI devices.
 *
 * The board info passed can safely be __initdata ... but be careful of
 * any embedded pointers (platform_data, etc), they're copied as-is.
 */
434
int spi_register_board_info(struct spi_board_info const *info, unsigned n)
435
{
436 437
	struct boardinfo *bi;
	int i;
438

439 440 441
	if (!n)
		return -EINVAL;

442
	bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
443 444 445
	if (!bi)
		return -ENOMEM;

446 447
	for (i = 0; i < n; i++, bi++, info++) {
		struct spi_master *master;
448

449 450 451 452 453 454
		memcpy(&bi->board_info, info, sizeof(*info));
		mutex_lock(&board_lock);
		list_add_tail(&bi->list, &board_list);
		list_for_each_entry(master, &spi_master_list, list)
			spi_match_master_to_boardinfo(master, &bi->board_info);
		mutex_unlock(&board_lock);
455
	}
456 457

	return 0;
458 459 460 461
}

/*-------------------------------------------------------------------------*/

462 463 464 465 466 467 468 469 470 471 472
static void spi_set_cs(struct spi_device *spi, bool enable)
{
	if (spi->mode & SPI_CS_HIGH)
		enable = !enable;

	if (spi->cs_gpio >= 0)
		gpio_set_value(spi->cs_gpio, !enable);
	else if (spi->master->set_cs)
		spi->master->set_cs(spi, !enable);
}

473
#ifdef CONFIG_HAS_DMA
474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498
static int spi_map_buf(struct spi_master *master, struct device *dev,
		       struct sg_table *sgt, void *buf, size_t len,
		       enum dma_data_direction dir)
{
	const bool vmalloced_buf = is_vmalloc_addr(buf);
	const int desc_len = vmalloced_buf ? PAGE_SIZE : master->max_dma_len;
	const int sgs = DIV_ROUND_UP(len, desc_len);
	struct page *vm_page;
	void *sg_buf;
	size_t min;
	int i, ret;

	ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
	if (ret != 0)
		return ret;

	for (i = 0; i < sgs; i++) {
		min = min_t(size_t, len, desc_len);

		if (vmalloced_buf) {
			vm_page = vmalloc_to_page(buf);
			if (!vm_page) {
				sg_free_table(sgt);
				return -ENOMEM;
			}
499 500
			sg_set_page(&sgt->sgl[i], vm_page,
				    min, offset_in_page(buf));
501 502
		} else {
			sg_buf = buf;
503
			sg_set_buf(&sgt->sgl[i], sg_buf, min);
504 505 506 507 508 509 510 511
		}


		buf += min;
		len -= min;
	}

	ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
512 513
	if (!ret)
		ret = -ENOMEM;
514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532
	if (ret < 0) {
		sg_free_table(sgt);
		return ret;
	}

	sgt->nents = ret;

	return 0;
}

static void spi_unmap_buf(struct spi_master *master, struct device *dev,
			  struct sg_table *sgt, enum dma_data_direction dir)
{
	if (sgt->orig_nents) {
		dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
		sg_free_table(sgt);
	}
}

533
static int __spi_map_msg(struct spi_master *master, struct spi_message *msg)
534 535 536
{
	struct device *tx_dev, *rx_dev;
	struct spi_transfer *xfer;
537
	int ret;
538

539
	if (!master->can_dma)
540 541
		return 0;

542 543
	tx_dev = master->dma_tx->device->dev;
	rx_dev = master->dma_rx->device->dev;
544 545 546 547 548 549

	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
		if (!master->can_dma(master, msg->spi, xfer))
			continue;

		if (xfer->tx_buf != NULL) {
550 551 552 553 554
			ret = spi_map_buf(master, tx_dev, &xfer->tx_sg,
					  (void *)xfer->tx_buf, xfer->len,
					  DMA_TO_DEVICE);
			if (ret != 0)
				return ret;
555 556 557
		}

		if (xfer->rx_buf != NULL) {
558 559 560 561 562 563 564
			ret = spi_map_buf(master, rx_dev, &xfer->rx_sg,
					  xfer->rx_buf, xfer->len,
					  DMA_FROM_DEVICE);
			if (ret != 0) {
				spi_unmap_buf(master, tx_dev, &xfer->tx_sg,
					      DMA_TO_DEVICE);
				return ret;
565 566 567 568 569 570 571 572 573
			}
		}
	}

	master->cur_msg_mapped = true;

	return 0;
}

574
static int __spi_unmap_msg(struct spi_master *master, struct spi_message *msg)
575 576 577 578
{
	struct spi_transfer *xfer;
	struct device *tx_dev, *rx_dev;

579
	if (!master->cur_msg_mapped || !master->can_dma)
580 581
		return 0;

582 583
	tx_dev = master->dma_tx->device->dev;
	rx_dev = master->dma_rx->device->dev;
584 585 586 587 588

	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
		if (!master->can_dma(master, msg->spi, xfer))
			continue;

589 590
		spi_unmap_buf(master, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
		spi_unmap_buf(master, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
591 592 593 594
	}

	return 0;
}
595 596 597 598 599 600 601
#else /* !CONFIG_HAS_DMA */
static inline int __spi_map_msg(struct spi_master *master,
				struct spi_message *msg)
{
	return 0;
}

602 603
static inline int __spi_unmap_msg(struct spi_master *master,
				  struct spi_message *msg)
604 605 606 607 608
{
	return 0;
}
#endif /* !CONFIG_HAS_DMA */

609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627
static inline int spi_unmap_msg(struct spi_master *master,
				struct spi_message *msg)
{
	struct spi_transfer *xfer;

	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
		/*
		 * Restore the original value of tx_buf or rx_buf if they are
		 * NULL.
		 */
		if (xfer->tx_buf == master->dummy_tx)
			xfer->tx_buf = NULL;
		if (xfer->rx_buf == master->dummy_rx)
			xfer->rx_buf = NULL;
	}

	return __spi_unmap_msg(master, msg);
}

628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676
static int spi_map_msg(struct spi_master *master, struct spi_message *msg)
{
	struct spi_transfer *xfer;
	void *tmp;
	unsigned int max_tx, max_rx;

	if (master->flags & (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX)) {
		max_tx = 0;
		max_rx = 0;

		list_for_each_entry(xfer, &msg->transfers, transfer_list) {
			if ((master->flags & SPI_MASTER_MUST_TX) &&
			    !xfer->tx_buf)
				max_tx = max(xfer->len, max_tx);
			if ((master->flags & SPI_MASTER_MUST_RX) &&
			    !xfer->rx_buf)
				max_rx = max(xfer->len, max_rx);
		}

		if (max_tx) {
			tmp = krealloc(master->dummy_tx, max_tx,
				       GFP_KERNEL | GFP_DMA);
			if (!tmp)
				return -ENOMEM;
			master->dummy_tx = tmp;
			memset(tmp, 0, max_tx);
		}

		if (max_rx) {
			tmp = krealloc(master->dummy_rx, max_rx,
				       GFP_KERNEL | GFP_DMA);
			if (!tmp)
				return -ENOMEM;
			master->dummy_rx = tmp;
		}

		if (max_tx || max_rx) {
			list_for_each_entry(xfer, &msg->transfers,
					    transfer_list) {
				if (!xfer->tx_buf)
					xfer->tx_buf = master->dummy_tx;
				if (!xfer->rx_buf)
					xfer->rx_buf = master->dummy_rx;
			}
		}
	}

	return __spi_map_msg(master, msg);
}
677

678 679 680 681 682 683 684 685 686 687 688 689 690
/*
 * spi_transfer_one_message - Default implementation of transfer_one_message()
 *
 * This is a standard implementation of transfer_one_message() for
 * drivers which impelment a transfer_one() operation.  It provides
 * standard handling of delays and chip select management.
 */
static int spi_transfer_one_message(struct spi_master *master,
				    struct spi_message *msg)
{
	struct spi_transfer *xfer;
	bool keep_cs = false;
	int ret = 0;
691
	unsigned long ms = 1;
692 693 694 695 696 697

	spi_set_cs(msg->spi, true);

	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
		trace_spi_transfer_start(msg, xfer);

698 699
		if (xfer->tx_buf || xfer->rx_buf) {
			reinit_completion(&master->xfer_completion);
700

701 702 703 704 705 706
			ret = master->transfer_one(master, msg->spi, xfer);
			if (ret < 0) {
				dev_err(&msg->spi->dev,
					"SPI transfer failed: %d\n", ret);
				goto out;
			}
707

708 709 710 711
			if (ret > 0) {
				ret = 0;
				ms = xfer->len * 8 * 1000 / xfer->speed_hz;
				ms += ms + 100; /* some tolerance */
712

713 714 715
				ms = wait_for_completion_timeout(&master->xfer_completion,
								 msecs_to_jiffies(ms));
			}
716

717 718 719 720 721 722 723 724 725 726
			if (ms == 0) {
				dev_err(&msg->spi->dev,
					"SPI transfer timed out\n");
				msg->status = -ETIMEDOUT;
			}
		} else {
			if (xfer->len)
				dev_err(&msg->spi->dev,
					"Bufferless transfer has length %u\n",
					xfer->len);
727
		}
728 729 730 731 732 733 734 735 736 737 738 739 740 741

		trace_spi_transfer_stop(msg, xfer);

		if (msg->status != -EINPROGRESS)
			goto out;

		if (xfer->delay_usecs)
			udelay(xfer->delay_usecs);

		if (xfer->cs_change) {
			if (list_is_last(&xfer->transfer_list,
					 &msg->transfers)) {
				keep_cs = true;
			} else {
742 743 744
				spi_set_cs(msg->spi, false);
				udelay(10);
				spi_set_cs(msg->spi, true);
745 746 747 748 749 750 751 752 753 754 755 756 757
			}
		}

		msg->actual_length += xfer->len;
	}

out:
	if (ret != 0 || !keep_cs)
		spi_set_cs(msg->spi, false);

	if (msg->status == -EINPROGRESS)
		msg->status = ret;

758
	if (msg->status && master->handle_err)
759 760
		master->handle_err(master, msg);

761 762 763 764 765 766 767
	spi_finalize_current_message(master);

	return ret;
}

/**
 * spi_finalize_current_transfer - report completion of a transfer
T
Thierry Reding 已提交
768
 * @master: the master reporting completion
769 770 771
 *
 * Called by SPI drivers using the core transfer_one_message()
 * implementation to notify it that the current interrupt driven
772
 * transfer has finished and the next one may be scheduled.
773 774 775 776 777 778 779
 */
void spi_finalize_current_transfer(struct spi_master *master)
{
	complete(&master->xfer_completion);
}
EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);

780
/**
781 782 783
 * __spi_pump_messages - function which processes spi message queue
 * @master: master to process queue for
 * @in_kthread: true if we are in the context of the message pump thread
784 785 786 787 788
 *
 * This function checks if there is any spi message in the queue that
 * needs processing and if so call out to the driver to initialize hardware
 * and transfer each message.
 *
789 790 791
 * Note that it is called both from the kthread itself and also from
 * inside spi_sync(); the queue extraction handling at the top of the
 * function should deal with this safely.
792
 */
793
static void __spi_pump_messages(struct spi_master *master, bool in_kthread)
794 795 796 797 798
{
	unsigned long flags;
	bool was_busy = false;
	int ret;

799
	/* Lock queue */
800
	spin_lock_irqsave(&master->queue_lock, flags);
801 802 803 804 805 806 807

	/* Make sure we are not already running a message */
	if (master->cur_msg) {
		spin_unlock_irqrestore(&master->queue_lock, flags);
		return;
	}

808 809 810 811 812 813 814
	/* If another context is idling the device then defer */
	if (master->idling) {
		queue_kthread_work(&master->kworker, &master->pump_messages);
		spin_unlock_irqrestore(&master->queue_lock, flags);
		return;
	}

815
	/* Check if the queue is idle */
816
	if (list_empty(&master->queue) || !master->running) {
817 818 819
		if (!master->busy) {
			spin_unlock_irqrestore(&master->queue_lock, flags);
			return;
820
		}
821 822 823 824 825 826 827 828 829

		/* Only do teardown in the thread */
		if (!in_kthread) {
			queue_kthread_work(&master->kworker,
					   &master->pump_messages);
			spin_unlock_irqrestore(&master->queue_lock, flags);
			return;
		}

830
		master->busy = false;
831
		master->idling = true;
832
		spin_unlock_irqrestore(&master->queue_lock, flags);
833

834 835 836 837
		kfree(master->dummy_rx);
		master->dummy_rx = NULL;
		kfree(master->dummy_tx);
		master->dummy_tx = NULL;
838 839 840 841
		if (master->unprepare_transfer_hardware &&
		    master->unprepare_transfer_hardware(master))
			dev_err(&master->dev,
				"failed to unprepare transfer hardware\n");
842 843 844 845
		if (master->auto_runtime_pm) {
			pm_runtime_mark_last_busy(master->dev.parent);
			pm_runtime_put_autosuspend(master->dev.parent);
		}
846
		trace_spi_master_idle(master);
847

848 849
		spin_lock_irqsave(&master->queue_lock, flags);
		master->idling = false;
850 851 852 853 854 855
		spin_unlock_irqrestore(&master->queue_lock, flags);
		return;
	}

	/* Extract head of queue */
	master->cur_msg =
856
		list_first_entry(&master->queue, struct spi_message, queue);
857 858 859 860 861 862 863 864

	list_del_init(&master->cur_msg->queue);
	if (master->busy)
		was_busy = true;
	else
		master->busy = true;
	spin_unlock_irqrestore(&master->queue_lock, flags);

865 866 867 868 869 870 871 872 873
	if (!was_busy && master->auto_runtime_pm) {
		ret = pm_runtime_get_sync(master->dev.parent);
		if (ret < 0) {
			dev_err(&master->dev, "Failed to power device: %d\n",
				ret);
			return;
		}
	}

874 875 876
	if (!was_busy)
		trace_spi_master_busy(master);

877
	if (!was_busy && master->prepare_transfer_hardware) {
878 879 880 881
		ret = master->prepare_transfer_hardware(master);
		if (ret) {
			dev_err(&master->dev,
				"failed to prepare transfer hardware\n");
882 883 884

			if (master->auto_runtime_pm)
				pm_runtime_put(master->dev.parent);
885 886 887 888
			return;
		}
	}

889 890
	trace_spi_message_start(master->cur_msg);

891 892 893 894 895 896 897 898 899 900 901 902
	if (master->prepare_message) {
		ret = master->prepare_message(master, master->cur_msg);
		if (ret) {
			dev_err(&master->dev,
				"failed to prepare message: %d\n", ret);
			master->cur_msg->status = ret;
			spi_finalize_current_message(master);
			return;
		}
		master->cur_msg_prepared = true;
	}

903 904 905 906 907 908 909
	ret = spi_map_msg(master, master->cur_msg);
	if (ret) {
		master->cur_msg->status = ret;
		spi_finalize_current_message(master);
		return;
	}

910 911 912
	ret = master->transfer_one_message(master, master->cur_msg);
	if (ret) {
		dev_err(&master->dev,
913
			"failed to transfer one message from queue\n");
914 915 916 917
		return;
	}
}

918 919 920 921 922 923 924 925 926 927 928 929
/**
 * spi_pump_messages - kthread work function which processes spi message queue
 * @work: pointer to kthread work struct contained in the master struct
 */
static void spi_pump_messages(struct kthread_work *work)
{
	struct spi_master *master =
		container_of(work, struct spi_master, pump_messages);

	__spi_pump_messages(master, true);
}

930 931 932 933 934 935 936 937 938
static int spi_init_queue(struct spi_master *master)
{
	struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };

	master->running = false;
	master->busy = false;

	init_kthread_worker(&master->kworker);
	master->kworker_task = kthread_run(kthread_worker_fn,
939
					   &master->kworker, "%s",
940 941 942
					   dev_name(&master->dev));
	if (IS_ERR(master->kworker_task)) {
		dev_err(&master->dev, "failed to create message pump task\n");
943
		return PTR_ERR(master->kworker_task);
944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977
	}
	init_kthread_work(&master->pump_messages, spi_pump_messages);

	/*
	 * Master config will indicate if this controller should run the
	 * message pump with high (realtime) priority to reduce the transfer
	 * latency on the bus by minimising the delay between a transfer
	 * request and the scheduling of the message pump thread. Without this
	 * setting the message pump thread will remain at default priority.
	 */
	if (master->rt) {
		dev_info(&master->dev,
			"will run message pump with realtime priority\n");
		sched_setscheduler(master->kworker_task, SCHED_FIFO, &param);
	}

	return 0;
}

/**
 * spi_get_next_queued_message() - called by driver to check for queued
 * messages
 * @master: the master to check for queued messages
 *
 * If there are more messages in the queue, the next message is returned from
 * this call.
 */
struct spi_message *spi_get_next_queued_message(struct spi_master *master)
{
	struct spi_message *next;
	unsigned long flags;

	/* get a pointer to the next message, if any */
	spin_lock_irqsave(&master->queue_lock, flags);
978 979
	next = list_first_entry_or_null(&master->queue, struct spi_message,
					queue);
980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996
	spin_unlock_irqrestore(&master->queue_lock, flags);

	return next;
}
EXPORT_SYMBOL_GPL(spi_get_next_queued_message);

/**
 * spi_finalize_current_message() - the current message is complete
 * @master: the master to return the message to
 *
 * Called by the driver to notify the core that the message in the front of the
 * queue is complete and can be removed from the queue.
 */
void spi_finalize_current_message(struct spi_master *master)
{
	struct spi_message *mesg;
	unsigned long flags;
997
	int ret;
998 999 1000 1001 1002

	spin_lock_irqsave(&master->queue_lock, flags);
	mesg = master->cur_msg;
	spin_unlock_irqrestore(&master->queue_lock, flags);

1003 1004
	spi_unmap_msg(master, mesg);

1005 1006 1007 1008 1009 1010 1011
	if (master->cur_msg_prepared && master->unprepare_message) {
		ret = master->unprepare_message(master, mesg);
		if (ret) {
			dev_err(&master->dev,
				"failed to unprepare message: %d\n", ret);
		}
	}
1012

1013 1014
	spin_lock_irqsave(&master->queue_lock, flags);
	master->cur_msg = NULL;
1015
	master->cur_msg_prepared = false;
1016 1017 1018 1019
	queue_kthread_work(&master->kworker, &master->pump_messages);
	spin_unlock_irqrestore(&master->queue_lock, flags);

	trace_spi_message_done(mesg);
1020

1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062
	mesg->state = NULL;
	if (mesg->complete)
		mesg->complete(mesg->context);
}
EXPORT_SYMBOL_GPL(spi_finalize_current_message);

static int spi_start_queue(struct spi_master *master)
{
	unsigned long flags;

	spin_lock_irqsave(&master->queue_lock, flags);

	if (master->running || master->busy) {
		spin_unlock_irqrestore(&master->queue_lock, flags);
		return -EBUSY;
	}

	master->running = true;
	master->cur_msg = NULL;
	spin_unlock_irqrestore(&master->queue_lock, flags);

	queue_kthread_work(&master->kworker, &master->pump_messages);

	return 0;
}

static int spi_stop_queue(struct spi_master *master)
{
	unsigned long flags;
	unsigned limit = 500;
	int ret = 0;

	spin_lock_irqsave(&master->queue_lock, flags);

	/*
	 * This is a bit lame, but is optimized for the common execution path.
	 * A wait_queue on the master->busy could be used, but then the common
	 * execution path (pump_messages) would be required to call wake_up or
	 * friends on every SPI message. Do this instead.
	 */
	while ((!list_empty(&master->queue) || master->busy) && limit--) {
		spin_unlock_irqrestore(&master->queue_lock, flags);
1063
		usleep_range(10000, 11000);
1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104
		spin_lock_irqsave(&master->queue_lock, flags);
	}

	if (!list_empty(&master->queue) || master->busy)
		ret = -EBUSY;
	else
		master->running = false;

	spin_unlock_irqrestore(&master->queue_lock, flags);

	if (ret) {
		dev_warn(&master->dev,
			 "could not stop message queue\n");
		return ret;
	}
	return ret;
}

static int spi_destroy_queue(struct spi_master *master)
{
	int ret;

	ret = spi_stop_queue(master);

	/*
	 * flush_kthread_worker will block until all work is done.
	 * If the reason that stop_queue timed out is that the work will never
	 * finish, then it does no good to call flush/stop thread, so
	 * return anyway.
	 */
	if (ret) {
		dev_err(&master->dev, "problem destroying queue\n");
		return ret;
	}

	flush_kthread_worker(&master->kworker);
	kthread_stop(master->kworker_task);

	return 0;
}

1105 1106 1107
static int __spi_queued_transfer(struct spi_device *spi,
				 struct spi_message *msg,
				 bool need_pump)
1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121
{
	struct spi_master *master = spi->master;
	unsigned long flags;

	spin_lock_irqsave(&master->queue_lock, flags);

	if (!master->running) {
		spin_unlock_irqrestore(&master->queue_lock, flags);
		return -ESHUTDOWN;
	}
	msg->actual_length = 0;
	msg->status = -EINPROGRESS;

	list_add_tail(&msg->queue, &master->queue);
1122
	if (!master->busy && need_pump)
1123 1124 1125 1126 1127 1128
		queue_kthread_work(&master->kworker, &master->pump_messages);

	spin_unlock_irqrestore(&master->queue_lock, flags);
	return 0;
}

1129 1130 1131 1132 1133 1134 1135 1136 1137 1138
/**
 * spi_queued_transfer - transfer function for queued transfers
 * @spi: spi device which is requesting transfer
 * @msg: spi message which is to handled is queued to driver queue
 */
static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
{
	return __spi_queued_transfer(spi, msg, true);
}

1139 1140 1141 1142 1143
static int spi_master_initialize_queue(struct spi_master *master)
{
	int ret;

	master->transfer = spi_queued_transfer;
1144 1145
	if (!master->transfer_one_message)
		master->transfer_one_message = spi_transfer_one_message;
1146 1147 1148 1149 1150 1151 1152

	/* Initialize and start queue */
	ret = spi_init_queue(master);
	if (ret) {
		dev_err(&master->dev, "problem initializing queue\n");
		goto err_init_queue;
	}
1153
	master->queued = true;
1154 1155 1156 1157 1158 1159 1160 1161 1162 1163
	ret = spi_start_queue(master);
	if (ret) {
		dev_err(&master->dev, "problem starting queue\n");
		goto err_start_queue;
	}

	return 0;

err_start_queue:
	spi_destroy_queue(master);
1164
err_init_queue:
1165 1166 1167 1168 1169
	return ret;
}

/*-------------------------------------------------------------------------*/

1170
#if defined(CONFIG_OF)
1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284
static struct spi_device *
of_register_spi_device(struct spi_master *master, struct device_node *nc)
{
	struct spi_device *spi;
	int rc;
	u32 value;

	/* Alloc an spi_device */
	spi = spi_alloc_device(master);
	if (!spi) {
		dev_err(&master->dev, "spi_device alloc error for %s\n",
			nc->full_name);
		rc = -ENOMEM;
		goto err_out;
	}

	/* Select device driver */
	rc = of_modalias_node(nc, spi->modalias,
				sizeof(spi->modalias));
	if (rc < 0) {
		dev_err(&master->dev, "cannot find modalias for %s\n",
			nc->full_name);
		goto err_out;
	}

	/* Device address */
	rc = of_property_read_u32(nc, "reg", &value);
	if (rc) {
		dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
			nc->full_name, rc);
		goto err_out;
	}
	spi->chip_select = value;

	/* Mode (clock phase/polarity/etc.) */
	if (of_find_property(nc, "spi-cpha", NULL))
		spi->mode |= SPI_CPHA;
	if (of_find_property(nc, "spi-cpol", NULL))
		spi->mode |= SPI_CPOL;
	if (of_find_property(nc, "spi-cs-high", NULL))
		spi->mode |= SPI_CS_HIGH;
	if (of_find_property(nc, "spi-3wire", NULL))
		spi->mode |= SPI_3WIRE;
	if (of_find_property(nc, "spi-lsb-first", NULL))
		spi->mode |= SPI_LSB_FIRST;

	/* Device DUAL/QUAD mode */
	if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
		switch (value) {
		case 1:
			break;
		case 2:
			spi->mode |= SPI_TX_DUAL;
			break;
		case 4:
			spi->mode |= SPI_TX_QUAD;
			break;
		default:
			dev_warn(&master->dev,
				"spi-tx-bus-width %d not supported\n",
				value);
			break;
		}
	}

	if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
		switch (value) {
		case 1:
			break;
		case 2:
			spi->mode |= SPI_RX_DUAL;
			break;
		case 4:
			spi->mode |= SPI_RX_QUAD;
			break;
		default:
			dev_warn(&master->dev,
				"spi-rx-bus-width %d not supported\n",
				value);
			break;
		}
	}

	/* Device speed */
	rc = of_property_read_u32(nc, "spi-max-frequency", &value);
	if (rc) {
		dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
			nc->full_name, rc);
		goto err_out;
	}
	spi->max_speed_hz = value;

	/* IRQ */
	spi->irq = irq_of_parse_and_map(nc, 0);

	/* Store a pointer to the node in the device structure */
	of_node_get(nc);
	spi->dev.of_node = nc;

	/* Register the new device */
	rc = spi_add_device(spi);
	if (rc) {
		dev_err(&master->dev, "spi_device register error %s\n",
			nc->full_name);
		goto err_out;
	}

	return spi;

err_out:
	spi_dev_put(spi);
	return ERR_PTR(rc);
}

1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299
/**
 * of_register_spi_devices() - Register child devices onto the SPI bus
 * @master:	Pointer to spi_master device
 *
 * Registers an spi_device for each child node of master node which has a 'reg'
 * property.
 */
static void of_register_spi_devices(struct spi_master *master)
{
	struct spi_device *spi;
	struct device_node *nc;

	if (!master->dev.of_node)
		return;

1300
	for_each_available_child_of_node(master->dev.of_node, nc) {
1301 1302 1303
		spi = of_register_spi_device(master, nc);
		if (IS_ERR(spi))
			dev_warn(&master->dev, "Failed to create SPI device for %s\n",
1304 1305 1306 1307 1308 1309 1310
				nc->full_name);
	}
}
#else
static void of_register_spi_devices(struct spi_master *master) { }
#endif

1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362
#ifdef CONFIG_ACPI
static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
{
	struct spi_device *spi = data;

	if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
		struct acpi_resource_spi_serialbus *sb;

		sb = &ares->data.spi_serial_bus;
		if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
			spi->chip_select = sb->device_selection;
			spi->max_speed_hz = sb->connection_speed;

			if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
				spi->mode |= SPI_CPHA;
			if (sb->clock_polarity == ACPI_SPI_START_HIGH)
				spi->mode |= SPI_CPOL;
			if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
				spi->mode |= SPI_CS_HIGH;
		}
	} else if (spi->irq < 0) {
		struct resource r;

		if (acpi_dev_resource_interrupt(ares, 0, &r))
			spi->irq = r.start;
	}

	/* Always tell the ACPI core to skip this resource */
	return 1;
}

static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
				       void *data, void **return_value)
{
	struct spi_master *master = data;
	struct list_head resource_list;
	struct acpi_device *adev;
	struct spi_device *spi;
	int ret;

	if (acpi_bus_get_device(handle, &adev))
		return AE_OK;
	if (acpi_bus_get_status(adev) || !adev->status.present)
		return AE_OK;

	spi = spi_alloc_device(master);
	if (!spi) {
		dev_err(&master->dev, "failed to allocate SPI device for %s\n",
			dev_name(&adev->dev));
		return AE_NO_MEMORY;
	}

1363
	ACPI_COMPANION_SET(&spi->dev, adev);
1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375
	spi->irq = -1;

	INIT_LIST_HEAD(&resource_list);
	ret = acpi_dev_get_resources(adev, &resource_list,
				     acpi_spi_add_resource, spi);
	acpi_dev_free_resource_list(&resource_list);

	if (ret < 0 || !spi->max_speed_hz) {
		spi_dev_put(spi);
		return AE_OK;
	}

1376
	adev->power.flags.ignore_parent = true;
1377
	strlcpy(spi->modalias, acpi_device_hid(adev), sizeof(spi->modalias));
1378
	if (spi_add_device(spi)) {
1379
		adev->power.flags.ignore_parent = false;
1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392
		dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
			dev_name(&adev->dev));
		spi_dev_put(spi);
	}

	return AE_OK;
}

static void acpi_register_spi_devices(struct spi_master *master)
{
	acpi_status status;
	acpi_handle handle;

1393
	handle = ACPI_HANDLE(master->dev.parent);
1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406
	if (!handle)
		return;

	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
				     acpi_spi_add_device, NULL,
				     master, NULL);
	if (ACPI_FAILURE(status))
		dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
}
#else
static inline void acpi_register_spi_devices(struct spi_master *master) {}
#endif /* CONFIG_ACPI */

T
Tony Jones 已提交
1407
static void spi_master_release(struct device *dev)
1408 1409 1410
{
	struct spi_master *master;

T
Tony Jones 已提交
1411
	master = container_of(dev, struct spi_master, dev);
1412 1413 1414 1415 1416 1417
	kfree(master);
}

static struct class spi_master_class = {
	.name		= "spi_master",
	.owner		= THIS_MODULE,
T
Tony Jones 已提交
1418
	.dev_release	= spi_master_release,
1419 1420 1421
};


1422

1423 1424 1425
/**
 * spi_alloc_master - allocate SPI master controller
 * @dev: the controller, possibly using the platform_bus
D
David Brownell 已提交
1426
 * @size: how much zeroed driver-private data to allocate; the pointer to this
T
Tony Jones 已提交
1427
 *	memory is in the driver_data field of the returned device,
D
David Brownell 已提交
1428
 *	accessible with spi_master_get_devdata().
D
David Brownell 已提交
1429
 * Context: can sleep
1430 1431 1432
 *
 * This call is used only by SPI master controller drivers, which are the
 * only ones directly touching chip registers.  It's how they allocate
D
dmitry pervushin 已提交
1433
 * an spi_master structure, prior to calling spi_register_master().
1434 1435 1436 1437 1438
 *
 * This must be called from context that can sleep.  It returns the SPI
 * master structure on success, else NULL.
 *
 * The caller is responsible for assigning the bus number and initializing
D
dmitry pervushin 已提交
1439
 * the master's methods before calling spi_register_master(); and (after errors
1440 1441
 * adding the device) calling spi_master_put() and kfree() to prevent a memory
 * leak.
1442
 */
1443
struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
1444 1445 1446
{
	struct spi_master	*master;

D
David Brownell 已提交
1447 1448 1449
	if (!dev)
		return NULL;

J
Jingoo Han 已提交
1450
	master = kzalloc(size + sizeof(*master), GFP_KERNEL);
1451 1452 1453
	if (!master)
		return NULL;

T
Tony Jones 已提交
1454
	device_initialize(&master->dev);
1455 1456
	master->bus_num = -1;
	master->num_chipselect = 1;
T
Tony Jones 已提交
1457 1458
	master->dev.class = &spi_master_class;
	master->dev.parent = get_device(dev);
D
David Brownell 已提交
1459
	spi_master_set_devdata(master, &master[1]);
1460 1461 1462 1463 1464

	return master;
}
EXPORT_SYMBOL_GPL(spi_alloc_master);

1465 1466 1467
#ifdef CONFIG_OF
static int of_spi_register_master(struct spi_master *master)
{
1468
	int nb, i, *cs;
1469 1470 1471 1472 1473 1474
	struct device_node *np = master->dev.of_node;

	if (!np)
		return 0;

	nb = of_gpio_named_count(np, "cs-gpios");
J
Jingoo Han 已提交
1475
	master->num_chipselect = max_t(int, nb, master->num_chipselect);
1476

1477 1478
	/* Return error only for an incorrectly formed cs-gpios property */
	if (nb == 0 || nb == -ENOENT)
1479
		return 0;
1480 1481
	else if (nb < 0)
		return nb;
1482 1483 1484 1485 1486 1487 1488 1489 1490

	cs = devm_kzalloc(&master->dev,
			  sizeof(int) * master->num_chipselect,
			  GFP_KERNEL);
	master->cs_gpios = cs;

	if (!master->cs_gpios)
		return -ENOMEM;

1491
	for (i = 0; i < master->num_chipselect; i++)
1492
		cs[i] = -ENOENT;
1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505

	for (i = 0; i < nb; i++)
		cs[i] = of_get_named_gpio(np, "cs-gpios", i);

	return 0;
}
#else
static int of_spi_register_master(struct spi_master *master)
{
	return 0;
}
#endif

1506 1507 1508
/**
 * spi_register_master - register SPI master controller
 * @master: initialized master, originally from spi_alloc_master()
D
David Brownell 已提交
1509
 * Context: can sleep
1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522
 *
 * SPI master controllers connect to their drivers using some non-SPI bus,
 * such as the platform bus.  The final stage of probe() in that code
 * includes calling spi_register_master() to hook up to this SPI bus glue.
 *
 * SPI controllers use board specific (often SOC specific) bus numbers,
 * and board-specific addressing for SPI devices combines those numbers
 * with chip select numbers.  Since SPI does not directly support dynamic
 * device identification, boards need configuration tables telling which
 * chip is at which address.
 *
 * This must be called from context that can sleep.  It returns zero on
 * success, else a negative error code (dropping the master's refcount).
D
David Brownell 已提交
1523 1524
 * After a successful return, the caller is responsible for calling
 * spi_unregister_master().
1525
 */
1526
int spi_register_master(struct spi_master *master)
1527
{
1528
	static atomic_t		dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
T
Tony Jones 已提交
1529
	struct device		*dev = master->dev.parent;
1530
	struct boardinfo	*bi;
1531 1532 1533
	int			status = -ENODEV;
	int			dynamic = 0;

D
David Brownell 已提交
1534 1535 1536
	if (!dev)
		return -ENODEV;

1537 1538 1539 1540
	status = of_spi_register_master(master);
	if (status)
		return status;

1541 1542 1543 1544 1545 1546
	/* even if it's just one always-selected device, there must
	 * be at least one chipselect
	 */
	if (master->num_chipselect == 0)
		return -EINVAL;

1547 1548 1549
	if ((master->bus_num < 0) && master->dev.of_node)
		master->bus_num = of_alias_get_id(master->dev.of_node, "spi");

1550
	/* convention:  dynamically assigned bus IDs count down from the max */
1551
	if (master->bus_num < 0) {
1552 1553 1554
		/* FIXME switch to an IDR based scheme, something like
		 * I2C now uses, so we can't run out of "dynamic" IDs
		 */
1555
		master->bus_num = atomic_dec_return(&dyn_bus_id);
1556
		dynamic = 1;
1557 1558
	}

1559 1560
	INIT_LIST_HEAD(&master->queue);
	spin_lock_init(&master->queue_lock);
1561 1562 1563
	spin_lock_init(&master->bus_lock_spinlock);
	mutex_init(&master->bus_lock_mutex);
	master->bus_lock_flag = 0;
1564
	init_completion(&master->xfer_completion);
1565 1566
	if (!master->max_dma_len)
		master->max_dma_len = INT_MAX;
1567

1568 1569 1570
	/* register the device, then userspace will see it.
	 * registration fails if the bus ID is in use.
	 */
1571
	dev_set_name(&master->dev, "spi%u", master->bus_num);
T
Tony Jones 已提交
1572
	status = device_add(&master->dev);
1573
	if (status < 0)
1574
		goto done;
1575
	dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1576 1577
			dynamic ? " (dynamic)" : "");

1578 1579 1580 1581 1582 1583
	/* If we're using a queued driver, start the queue */
	if (master->transfer)
		dev_info(dev, "master is unqueued, this is deprecated\n");
	else {
		status = spi_master_initialize_queue(master);
		if (status) {
1584
			device_del(&master->dev);
1585 1586 1587 1588
			goto done;
		}
	}

1589 1590 1591 1592 1593 1594
	mutex_lock(&board_lock);
	list_add_tail(&master->list, &spi_master_list);
	list_for_each_entry(bi, &board_list, list)
		spi_match_master_to_boardinfo(master, &bi->board_info);
	mutex_unlock(&board_lock);

1595
	/* Register devices from the device tree and ACPI */
1596
	of_register_spi_devices(master);
1597
	acpi_register_spi_devices(master);
1598 1599 1600 1601 1602
done:
	return status;
}
EXPORT_SYMBOL_GPL(spi_register_master);

1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626
static void devm_spi_unregister(struct device *dev, void *res)
{
	spi_unregister_master(*(struct spi_master **)res);
}

/**
 * dev_spi_register_master - register managed SPI master controller
 * @dev:    device managing SPI master
 * @master: initialized master, originally from spi_alloc_master()
 * Context: can sleep
 *
 * Register a SPI device as with spi_register_master() which will
 * automatically be unregister
 */
int devm_spi_register_master(struct device *dev, struct spi_master *master)
{
	struct spi_master **ptr;
	int ret;

	ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
	if (!ptr)
		return -ENOMEM;

	ret = spi_register_master(master);
1627
	if (!ret) {
1628 1629 1630 1631 1632 1633 1634 1635 1636 1637
		*ptr = master;
		devres_add(dev, ptr);
	} else {
		devres_free(ptr);
	}

	return ret;
}
EXPORT_SYMBOL_GPL(devm_spi_register_master);

1638
static int __unregister(struct device *dev, void *null)
1639
{
1640
	spi_unregister_device(to_spi_device(dev));
1641 1642 1643 1644 1645 1646
	return 0;
}

/**
 * spi_unregister_master - unregister SPI master controller
 * @master: the master being unregistered
D
David Brownell 已提交
1647
 * Context: can sleep
1648 1649 1650 1651 1652 1653 1654 1655
 *
 * This call is used only by SPI master controller drivers, which are the
 * only ones directly touching chip registers.
 *
 * This must be called from context that can sleep.
 */
void spi_unregister_master(struct spi_master *master)
{
1656 1657
	int dummy;

1658 1659 1660 1661 1662
	if (master->queued) {
		if (spi_destroy_queue(master))
			dev_err(&master->dev, "queue remove failed\n");
	}

1663 1664 1665 1666
	mutex_lock(&board_lock);
	list_del(&master->list);
	mutex_unlock(&board_lock);

1667
	dummy = device_for_each_child(&master->dev, NULL, __unregister);
T
Tony Jones 已提交
1668
	device_unregister(&master->dev);
1669 1670 1671
}
EXPORT_SYMBOL_GPL(spi_unregister_master);

1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702
int spi_master_suspend(struct spi_master *master)
{
	int ret;

	/* Basically no-ops for non-queued masters */
	if (!master->queued)
		return 0;

	ret = spi_stop_queue(master);
	if (ret)
		dev_err(&master->dev, "queue stop failed\n");

	return ret;
}
EXPORT_SYMBOL_GPL(spi_master_suspend);

int spi_master_resume(struct spi_master *master)
{
	int ret;

	if (!master->queued)
		return 0;

	ret = spi_start_queue(master);
	if (ret)
		dev_err(&master->dev, "queue restart failed\n");

	return ret;
}
EXPORT_SYMBOL_GPL(spi_master_resume);

1703
static int __spi_master_match(struct device *dev, const void *data)
D
Dave Young 已提交
1704 1705
{
	struct spi_master *m;
1706
	const u16 *bus_num = data;
D
Dave Young 已提交
1707 1708 1709 1710 1711

	m = container_of(dev, struct spi_master, dev);
	return m->bus_num == *bus_num;
}

1712 1713 1714
/**
 * spi_busnum_to_master - look up master associated with bus_num
 * @bus_num: the master's bus number
D
David Brownell 已提交
1715
 * Context: can sleep
1716 1717 1718 1719 1720 1721 1722 1723
 *
 * This call may be used with devices that are registered after
 * arch init time.  It returns a refcounted pointer to the relevant
 * spi_master (which the caller must release), or NULL if there is
 * no such master registered.
 */
struct spi_master *spi_busnum_to_master(u16 bus_num)
{
T
Tony Jones 已提交
1724
	struct device		*dev;
1725
	struct spi_master	*master = NULL;
D
Dave Young 已提交
1726

1727
	dev = class_find_device(&spi_master_class, NULL, &bus_num,
D
Dave Young 已提交
1728 1729 1730 1731
				__spi_master_match);
	if (dev)
		master = container_of(dev, struct spi_master, dev);
	/* reference got in class_find_device */
1732
	return master;
1733 1734 1735 1736 1737 1738
}
EXPORT_SYMBOL_GPL(spi_busnum_to_master);


/*-------------------------------------------------------------------------*/

1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762
/* Core methods for SPI master protocol drivers.  Some of the
 * other core methods are currently defined as inline functions.
 */

/**
 * spi_setup - setup SPI mode and clock rate
 * @spi: the device whose settings are being modified
 * Context: can sleep, and no requests are queued to the device
 *
 * SPI protocol drivers may need to update the transfer mode if the
 * device doesn't work with its default.  They may likewise need
 * to update clock rates or word sizes from initial values.  This function
 * changes those settings, and must be called from a context that can sleep.
 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
 * effect the next time the device is selected and data is transferred to
 * or from it.  When this function returns, the spi device is deselected.
 *
 * Note that this call will fail if the protocol driver specifies an option
 * that the underlying controller or its driver does not support.  For
 * example, not all hardware supports wire transfers using nine bit words,
 * LSB-first wire encoding, or active-high chipselects.
 */
int spi_setup(struct spi_device *spi)
{
1763
	unsigned	bad_bits, ugly_bits;
1764
	int		status = 0;
1765

W
wangyuhang 已提交
1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778
	/* check mode to prevent that DUAL and QUAD set at the same time
	 */
	if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
		((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
		dev_err(&spi->dev,
		"setup: can not select dual and quad at the same time\n");
		return -EINVAL;
	}
	/* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
	 */
	if ((spi->mode & SPI_3WIRE) && (spi->mode &
		(SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
		return -EINVAL;
1779 1780 1781 1782
	/* help drivers fail *cleanly* when they need options
	 * that aren't supported with their current master
	 */
	bad_bits = spi->mode & ~spi->master->mode_bits;
1783 1784 1785 1786 1787 1788 1789 1790 1791
	ugly_bits = bad_bits &
		    (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD);
	if (ugly_bits) {
		dev_warn(&spi->dev,
			 "setup: ignoring unsupported mode bits %x\n",
			 ugly_bits);
		spi->mode &= ~ugly_bits;
		bad_bits &= ~ugly_bits;
	}
1792
	if (bad_bits) {
1793
		dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
1794 1795 1796 1797
			bad_bits);
		return -EINVAL;
	}

1798 1799 1800
	if (!spi->bits_per_word)
		spi->bits_per_word = 8;

1801 1802 1803
	if (!spi->max_speed_hz)
		spi->max_speed_hz = spi->master->max_speed_hz;

1804 1805
	spi_set_cs(spi, false);

1806 1807
	if (spi->master->setup)
		status = spi->master->setup(spi);
1808

J
Jingoo Han 已提交
1809
	dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821
			(int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
			(spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
			(spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
			(spi->mode & SPI_3WIRE) ? "3wire, " : "",
			(spi->mode & SPI_LOOP) ? "loopback, " : "",
			spi->bits_per_word, spi->max_speed_hz,
			status);

	return status;
}
EXPORT_SYMBOL_GPL(spi_setup);

1822
static int __spi_validate(struct spi_device *spi, struct spi_message *message)
1823 1824
{
	struct spi_master *master = spi->master;
1825
	struct spi_transfer *xfer;
1826
	int w_size;
1827

1828 1829 1830
	if (list_empty(&message->transfers))
		return -EINVAL;

1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849
	/* Half-duplex links include original MicroWire, and ones with
	 * only one data pin like SPI_3WIRE (switches direction) or where
	 * either MOSI or MISO is missing.  They can also be caused by
	 * software limitations.
	 */
	if ((master->flags & SPI_MASTER_HALF_DUPLEX)
			|| (spi->mode & SPI_3WIRE)) {
		unsigned flags = master->flags;

		list_for_each_entry(xfer, &message->transfers, transfer_list) {
			if (xfer->rx_buf && xfer->tx_buf)
				return -EINVAL;
			if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
				return -EINVAL;
			if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
				return -EINVAL;
		}
	}

1850
	/**
1851 1852
	 * Set transfer bits_per_word and max speed as spi device default if
	 * it is not set for this transfer.
W
wangyuhang 已提交
1853 1854
	 * Set transfer tx_nbits and rx_nbits as single transfer default
	 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
1855 1856
	 */
	list_for_each_entry(xfer, &message->transfers, transfer_list) {
1857
		message->frame_length += xfer->len;
1858 1859
		if (!xfer->bits_per_word)
			xfer->bits_per_word = spi->bits_per_word;
1860 1861

		if (!xfer->speed_hz)
1862
			xfer->speed_hz = spi->max_speed_hz;
1863 1864 1865 1866

		if (master->max_speed_hz &&
		    xfer->speed_hz > master->max_speed_hz)
			xfer->speed_hz = master->max_speed_hz;
1867

1868 1869 1870 1871 1872 1873 1874 1875
		if (master->bits_per_word_mask) {
			/* Only 32 bits fit in the mask */
			if (xfer->bits_per_word > 32)
				return -EINVAL;
			if (!(master->bits_per_word_mask &
					BIT(xfer->bits_per_word - 1)))
				return -EINVAL;
		}
1876

1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888
		/*
		 * SPI transfer length should be multiple of SPI word size
		 * where SPI word size should be power-of-two multiple
		 */
		if (xfer->bits_per_word <= 8)
			w_size = 1;
		else if (xfer->bits_per_word <= 16)
			w_size = 2;
		else
			w_size = 4;

		/* No partial transfers accepted */
1889
		if (xfer->len % w_size)
1890 1891
			return -EINVAL;

1892 1893 1894
		if (xfer->speed_hz && master->min_speed_hz &&
		    xfer->speed_hz < master->min_speed_hz)
			return -EINVAL;
W
wangyuhang 已提交
1895 1896 1897 1898 1899 1900

		if (xfer->tx_buf && !xfer->tx_nbits)
			xfer->tx_nbits = SPI_NBITS_SINGLE;
		if (xfer->rx_buf && !xfer->rx_nbits)
			xfer->rx_nbits = SPI_NBITS_SINGLE;
		/* check transfer tx/rx_nbits:
1901 1902
		 * 1. check the value matches one of single, dual and quad
		 * 2. check tx/rx_nbits match the mode in spi_device
W
wangyuhang 已提交
1903
		 */
1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915
		if (xfer->tx_buf) {
			if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
				xfer->tx_nbits != SPI_NBITS_DUAL &&
				xfer->tx_nbits != SPI_NBITS_QUAD)
				return -EINVAL;
			if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
				!(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
				return -EINVAL;
			if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
				!(spi->mode & SPI_TX_QUAD))
				return -EINVAL;
		}
W
wangyuhang 已提交
1916
		/* check transfer rx_nbits */
1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928
		if (xfer->rx_buf) {
			if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
				xfer->rx_nbits != SPI_NBITS_DUAL &&
				xfer->rx_nbits != SPI_NBITS_QUAD)
				return -EINVAL;
			if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
				!(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
				return -EINVAL;
			if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
				!(spi->mode & SPI_RX_QUAD))
				return -EINVAL;
		}
1929 1930
	}

1931
	message->status = -EINPROGRESS;
1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943

	return 0;
}

static int __spi_async(struct spi_device *spi, struct spi_message *message)
{
	struct spi_master *master = spi->master;

	message->spi = spi;

	trace_spi_message_submit(message);

1944 1945 1946
	return master->transfer(spi, message);
}

D
David Brownell 已提交
1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978
/**
 * spi_async - asynchronous SPI transfer
 * @spi: device with which data will be exchanged
 * @message: describes the data transfers, including completion callback
 * Context: any (irqs may be blocked, etc)
 *
 * This call may be used in_irq and other contexts which can't sleep,
 * as well as from task contexts which can sleep.
 *
 * The completion callback is invoked in a context which can't sleep.
 * Before that invocation, the value of message->status is undefined.
 * When the callback is issued, message->status holds either zero (to
 * indicate complete success) or a negative error code.  After that
 * callback returns, the driver which issued the transfer request may
 * deallocate the associated memory; it's no longer in use by any SPI
 * core or controller driver code.
 *
 * Note that although all messages to a spi_device are handled in
 * FIFO order, messages may go to different devices in other orders.
 * Some device might be higher priority, or have various "hard" access
 * time requirements, for example.
 *
 * On detection of any fault during the transfer, processing of
 * the entire message is aborted, and the device is deselected.
 * Until returning from the associated message completion callback,
 * no other spi_message queued to that device will be processed.
 * (This rule applies equally to all the synchronous transfer calls,
 * which are wrappers around this core asynchronous primitive.)
 */
int spi_async(struct spi_device *spi, struct spi_message *message)
{
	struct spi_master *master = spi->master;
1979 1980
	int ret;
	unsigned long flags;
D
David Brownell 已提交
1981

1982 1983 1984 1985
	ret = __spi_validate(spi, message);
	if (ret != 0)
		return ret;

1986
	spin_lock_irqsave(&master->bus_lock_spinlock, flags);
D
David Brownell 已提交
1987

1988 1989 1990 1991
	if (master->bus_lock_flag)
		ret = -EBUSY;
	else
		ret = __spi_async(spi, message);
D
David Brownell 已提交
1992

1993 1994 1995
	spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);

	return ret;
D
David Brownell 已提交
1996 1997 1998
}
EXPORT_SYMBOL_GPL(spi_async);

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033
/**
 * spi_async_locked - version of spi_async with exclusive bus usage
 * @spi: device with which data will be exchanged
 * @message: describes the data transfers, including completion callback
 * Context: any (irqs may be blocked, etc)
 *
 * This call may be used in_irq and other contexts which can't sleep,
 * as well as from task contexts which can sleep.
 *
 * The completion callback is invoked in a context which can't sleep.
 * Before that invocation, the value of message->status is undefined.
 * When the callback is issued, message->status holds either zero (to
 * indicate complete success) or a negative error code.  After that
 * callback returns, the driver which issued the transfer request may
 * deallocate the associated memory; it's no longer in use by any SPI
 * core or controller driver code.
 *
 * Note that although all messages to a spi_device are handled in
 * FIFO order, messages may go to different devices in other orders.
 * Some device might be higher priority, or have various "hard" access
 * time requirements, for example.
 *
 * On detection of any fault during the transfer, processing of
 * the entire message is aborted, and the device is deselected.
 * Until returning from the associated message completion callback,
 * no other spi_message queued to that device will be processed.
 * (This rule applies equally to all the synchronous transfer calls,
 * which are wrappers around this core asynchronous primitive.)
 */
int spi_async_locked(struct spi_device *spi, struct spi_message *message)
{
	struct spi_master *master = spi->master;
	int ret;
	unsigned long flags;

2034 2035 2036 2037
	ret = __spi_validate(spi, message);
	if (ret != 0)
		return ret;

2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048
	spin_lock_irqsave(&master->bus_lock_spinlock, flags);

	ret = __spi_async(spi, message);

	spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);

	return ret;

}
EXPORT_SYMBOL_GPL(spi_async_locked);

2049 2050 2051 2052 2053 2054 2055 2056

/*-------------------------------------------------------------------------*/

/* Utility methods for SPI master protocol drivers, layered on
 * top of the core.  Some other utility methods are defined as
 * inline functions.
 */

2057 2058 2059 2060 2061
static void spi_complete(void *arg)
{
	complete(arg);
}

2062 2063 2064 2065 2066 2067
static int __spi_sync(struct spi_device *spi, struct spi_message *message,
		      int bus_locked)
{
	DECLARE_COMPLETION_ONSTACK(done);
	int status;
	struct spi_master *master = spi->master;
2068 2069 2070 2071 2072
	unsigned long flags;

	status = __spi_validate(spi, message);
	if (status != 0)
		return status;
2073 2074 2075

	message->complete = spi_complete;
	message->context = &done;
2076
	message->spi = spi;
2077 2078 2079 2080

	if (!bus_locked)
		mutex_lock(&master->bus_lock_mutex);

2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096
	/* If we're not using the legacy transfer method then we will
	 * try to transfer in the calling context so special case.
	 * This code would be less tricky if we could remove the
	 * support for driver implemented message queues.
	 */
	if (master->transfer == spi_queued_transfer) {
		spin_lock_irqsave(&master->bus_lock_spinlock, flags);

		trace_spi_message_submit(message);

		status = __spi_queued_transfer(spi, message, false);

		spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
	} else {
		status = spi_async_locked(spi, message);
	}
2097 2098 2099 2100 2101

	if (!bus_locked)
		mutex_unlock(&master->bus_lock_mutex);

	if (status == 0) {
2102 2103 2104 2105
		/* Push out the messages in the calling context if we
		 * can.
		 */
		if (master->transfer == spi_queued_transfer)
2106
			__spi_pump_messages(master, false);
2107

2108 2109 2110 2111 2112 2113 2114
		wait_for_completion(&done);
		status = message->status;
	}
	message->context = NULL;
	return status;
}

2115 2116 2117 2118
/**
 * spi_sync - blocking/synchronous SPI data transfers
 * @spi: device with which data will be exchanged
 * @message: describes the data transfers
D
David Brownell 已提交
2119
 * Context: can sleep
2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130
 *
 * This call may only be used from a context that may sleep.  The sleep
 * is non-interruptible, and has no timeout.  Low-overhead controller
 * drivers may DMA directly into and out of the message buffers.
 *
 * Note that the SPI device's chip select is active during the message,
 * and then is normally disabled between messages.  Drivers for some
 * frequently-used devices may want to minimize costs of selecting a chip,
 * by leaving it selected in anticipation that the next message will go
 * to the same chip.  (That may increase power usage.)
 *
D
David Brownell 已提交
2131 2132 2133
 * Also, the caller is guaranteeing that the memory associated with the
 * message will not be freed before this call returns.
 *
2134
 * It returns zero on success, else a negative error code.
2135 2136 2137
 */
int spi_sync(struct spi_device *spi, struct spi_message *message)
{
2138
	return __spi_sync(spi, message, 0);
2139 2140 2141
}
EXPORT_SYMBOL_GPL(spi_sync);

2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152
/**
 * spi_sync_locked - version of spi_sync with exclusive bus usage
 * @spi: device with which data will be exchanged
 * @message: describes the data transfers
 * Context: can sleep
 *
 * This call may only be used from a context that may sleep.  The sleep
 * is non-interruptible, and has no timeout.  Low-overhead controller
 * drivers may DMA directly into and out of the message buffers.
 *
 * This call should be used by drivers that require exclusive access to the
L
Lucas De Marchi 已提交
2153
 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217
 * be released by a spi_bus_unlock call when the exclusive access is over.
 *
 * It returns zero on success, else a negative error code.
 */
int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
{
	return __spi_sync(spi, message, 1);
}
EXPORT_SYMBOL_GPL(spi_sync_locked);

/**
 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
 * @master: SPI bus master that should be locked for exclusive bus access
 * Context: can sleep
 *
 * This call may only be used from a context that may sleep.  The sleep
 * is non-interruptible, and has no timeout.
 *
 * This call should be used by drivers that require exclusive access to the
 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
 * exclusive access is over. Data transfer must be done by spi_sync_locked
 * and spi_async_locked calls when the SPI bus lock is held.
 *
 * It returns zero on success, else a negative error code.
 */
int spi_bus_lock(struct spi_master *master)
{
	unsigned long flags;

	mutex_lock(&master->bus_lock_mutex);

	spin_lock_irqsave(&master->bus_lock_spinlock, flags);
	master->bus_lock_flag = 1;
	spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);

	/* mutex remains locked until spi_bus_unlock is called */

	return 0;
}
EXPORT_SYMBOL_GPL(spi_bus_lock);

/**
 * spi_bus_unlock - release the lock for exclusive SPI bus usage
 * @master: SPI bus master that was locked for exclusive bus access
 * Context: can sleep
 *
 * This call may only be used from a context that may sleep.  The sleep
 * is non-interruptible, and has no timeout.
 *
 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
 * call.
 *
 * It returns zero on success, else a negative error code.
 */
int spi_bus_unlock(struct spi_master *master)
{
	master->bus_lock_flag = 0;

	mutex_unlock(&master->bus_lock_mutex);

	return 0;
}
EXPORT_SYMBOL_GPL(spi_bus_unlock);

2218
/* portable code must never pass more than 32 bytes */
J
Jingoo Han 已提交
2219
#define	SPI_BUFSIZ	max(32, SMP_CACHE_BYTES)
2220 2221 2222 2223 2224 2225 2226 2227

static u8	*buf;

/**
 * spi_write_then_read - SPI synchronous write followed by read
 * @spi: device with which data will be exchanged
 * @txbuf: data to be written (need not be dma-safe)
 * @n_tx: size of txbuf, in bytes
2228 2229
 * @rxbuf: buffer into which data will be read (need not be dma-safe)
 * @n_rx: size of rxbuf, in bytes
D
David Brownell 已提交
2230
 * Context: can sleep
2231 2232 2233 2234
 *
 * This performs a half duplex MicroWire style transaction with the
 * device, sending txbuf and then reading rxbuf.  The return value
 * is zero for success, else a negative errno status code.
2235
 * This call may only be used from a context that may sleep.
2236
 *
D
David Brownell 已提交
2237
 * Parameters to this routine are always copied using a small buffer;
D
David Brownell 已提交
2238 2239
 * portable code should never use this for more than 32 bytes.
 * Performance-sensitive or bulk transfer code should instead use
D
David Brownell 已提交
2240
 * spi_{async,sync}() calls with dma-safe buffers.
2241 2242
 */
int spi_write_then_read(struct spi_device *spi,
2243 2244
		const void *txbuf, unsigned n_tx,
		void *rxbuf, unsigned n_rx)
2245
{
D
David Brownell 已提交
2246
	static DEFINE_MUTEX(lock);
2247 2248 2249

	int			status;
	struct spi_message	message;
2250
	struct spi_transfer	x[2];
2251 2252
	u8			*local_buf;

2253 2254 2255 2256
	/* Use preallocated DMA-safe buffer if we can.  We can't avoid
	 * copying here, (as a pure convenience thing), but we can
	 * keep heap costs out of the hot path unless someone else is
	 * using the pre-allocated buffer or the transfer is too large.
2257
	 */
2258
	if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
2259 2260
		local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
				    GFP_KERNEL | GFP_DMA);
2261 2262 2263 2264 2265
		if (!local_buf)
			return -ENOMEM;
	} else {
		local_buf = buf;
	}
2266

2267
	spi_message_init(&message);
J
Jingoo Han 已提交
2268
	memset(x, 0, sizeof(x));
2269 2270 2271 2272 2273 2274 2275 2276
	if (n_tx) {
		x[0].len = n_tx;
		spi_message_add_tail(&x[0], &message);
	}
	if (n_rx) {
		x[1].len = n_rx;
		spi_message_add_tail(&x[1], &message);
	}
2277

2278
	memcpy(local_buf, txbuf, n_tx);
2279 2280
	x[0].tx_buf = local_buf;
	x[1].rx_buf = local_buf + n_tx;
2281 2282 2283

	/* do the i/o */
	status = spi_sync(spi, &message);
2284
	if (status == 0)
2285
		memcpy(rxbuf, x[1].rx_buf, n_rx);
2286

2287
	if (x[0].tx_buf == buf)
D
David Brownell 已提交
2288
		mutex_unlock(&lock);
2289 2290 2291 2292 2293 2294 2295 2296 2297
	else
		kfree(local_buf);

	return status;
}
EXPORT_SYMBOL_GPL(spi_write_then_read);

/*-------------------------------------------------------------------------*/

2298 2299 2300 2301 2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315 2316 2317 2318 2319 2320 2321 2322 2323 2324 2325 2326 2327 2328 2329 2330 2331 2332 2333 2334 2335 2336 2337 2338 2339 2340 2341 2342 2343 2344 2345 2346 2347 2348 2349 2350 2351 2352 2353 2354 2355 2356 2357 2358 2359 2360 2361 2362 2363 2364 2365 2366 2367 2368 2369 2370 2371 2372 2373 2374 2375 2376 2377
#if IS_ENABLED(CONFIG_OF_DYNAMIC)
static int __spi_of_device_match(struct device *dev, void *data)
{
	return dev->of_node == data;
}

/* must call put_device() when done with returned spi_device device */
static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
{
	struct device *dev = bus_find_device(&spi_bus_type, NULL, node,
						__spi_of_device_match);
	return dev ? to_spi_device(dev) : NULL;
}

static int __spi_of_master_match(struct device *dev, const void *data)
{
	return dev->of_node == data;
}

/* the spi masters are not using spi_bus, so we find it with another way */
static struct spi_master *of_find_spi_master_by_node(struct device_node *node)
{
	struct device *dev;

	dev = class_find_device(&spi_master_class, NULL, node,
				__spi_of_master_match);
	if (!dev)
		return NULL;

	/* reference got in class_find_device */
	return container_of(dev, struct spi_master, dev);
}

static int of_spi_notify(struct notifier_block *nb, unsigned long action,
			 void *arg)
{
	struct of_reconfig_data *rd = arg;
	struct spi_master *master;
	struct spi_device *spi;

	switch (of_reconfig_get_state_change(action, arg)) {
	case OF_RECONFIG_CHANGE_ADD:
		master = of_find_spi_master_by_node(rd->dn->parent);
		if (master == NULL)
			return NOTIFY_OK;	/* not for us */

		spi = of_register_spi_device(master, rd->dn);
		put_device(&master->dev);

		if (IS_ERR(spi)) {
			pr_err("%s: failed to create for '%s'\n",
					__func__, rd->dn->full_name);
			return notifier_from_errno(PTR_ERR(spi));
		}
		break;

	case OF_RECONFIG_CHANGE_REMOVE:
		/* find our device by node */
		spi = of_find_spi_device_by_node(rd->dn);
		if (spi == NULL)
			return NOTIFY_OK;	/* no? not meant for us */

		/* unregister takes one ref away */
		spi_unregister_device(spi);

		/* and put the reference of the find */
		put_device(&spi->dev);
		break;
	}

	return NOTIFY_OK;
}

static struct notifier_block spi_of_notifier = {
	.notifier_call = of_spi_notify,
};
#else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
extern struct notifier_block spi_of_notifier;
#endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */

2378 2379
static int __init spi_init(void)
{
2380 2381
	int	status;

2382
	buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
2383 2384 2385 2386 2387 2388 2389 2390
	if (!buf) {
		status = -ENOMEM;
		goto err0;
	}

	status = bus_register(&spi_bus_type);
	if (status < 0)
		goto err1;
2391

2392 2393 2394
	status = class_register(&spi_master_class);
	if (status < 0)
		goto err2;
2395

2396
	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2397 2398
		WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));

2399
	return 0;
2400 2401 2402 2403 2404 2405 2406 2407

err2:
	bus_unregister(&spi_bus_type);
err1:
	kfree(buf);
	buf = NULL;
err0:
	return status;
2408
}
2409

2410 2411
/* board_info is normally registered in arch_initcall(),
 * but even essential drivers wait till later
2412 2413 2414 2415
 *
 * REVISIT only boardinfo really needs static linking. the rest (device and
 * driver registration) _could_ be dynamically linked (modular) ... costs
 * include needing to have boardinfo data structures be much more public.
2416
 */
2417
postcore_initcall(spi_init);
2418