xref: /openbmc/linux/drivers/spi/spi.c (revision af958a38)
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  * You should have received a copy of the GNU General Public License
18  * along with this program; if not, write to the Free Software
19  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20  */
21 
22 #include <linux/kernel.h>
23 #include <linux/kmod.h>
24 #include <linux/device.h>
25 #include <linux/init.h>
26 #include <linux/cache.h>
27 #include <linux/dma-mapping.h>
28 #include <linux/dmaengine.h>
29 #include <linux/mutex.h>
30 #include <linux/of_device.h>
31 #include <linux/of_irq.h>
32 #include <linux/clk/clk-conf.h>
33 #include <linux/slab.h>
34 #include <linux/mod_devicetable.h>
35 #include <linux/spi/spi.h>
36 #include <linux/of_gpio.h>
37 #include <linux/pm_runtime.h>
38 #include <linux/export.h>
39 #include <linux/sched/rt.h>
40 #include <linux/delay.h>
41 #include <linux/kthread.h>
42 #include <linux/ioport.h>
43 #include <linux/acpi.h>
44 
45 #define CREATE_TRACE_POINTS
46 #include <trace/events/spi.h>
47 
48 static void spidev_release(struct device *dev)
49 {
50 	struct spi_device	*spi = to_spi_device(dev);
51 
52 	/* spi masters may cleanup for released devices */
53 	if (spi->master->cleanup)
54 		spi->master->cleanup(spi);
55 
56 	spi_master_put(spi->master);
57 	kfree(spi);
58 }
59 
60 static ssize_t
61 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
62 {
63 	const struct spi_device	*spi = to_spi_device(dev);
64 	int len;
65 
66 	len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
67 	if (len != -ENODEV)
68 		return len;
69 
70 	return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
71 }
72 static DEVICE_ATTR_RO(modalias);
73 
74 static struct attribute *spi_dev_attrs[] = {
75 	&dev_attr_modalias.attr,
76 	NULL,
77 };
78 ATTRIBUTE_GROUPS(spi_dev);
79 
80 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
81  * and the sysfs version makes coldplug work too.
82  */
83 
84 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
85 						const struct spi_device *sdev)
86 {
87 	while (id->name[0]) {
88 		if (!strcmp(sdev->modalias, id->name))
89 			return id;
90 		id++;
91 	}
92 	return NULL;
93 }
94 
95 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
96 {
97 	const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
98 
99 	return spi_match_id(sdrv->id_table, sdev);
100 }
101 EXPORT_SYMBOL_GPL(spi_get_device_id);
102 
103 static int spi_match_device(struct device *dev, struct device_driver *drv)
104 {
105 	const struct spi_device	*spi = to_spi_device(dev);
106 	const struct spi_driver	*sdrv = to_spi_driver(drv);
107 
108 	/* Attempt an OF style match */
109 	if (of_driver_match_device(dev, drv))
110 		return 1;
111 
112 	/* Then try ACPI */
113 	if (acpi_driver_match_device(dev, drv))
114 		return 1;
115 
116 	if (sdrv->id_table)
117 		return !!spi_match_id(sdrv->id_table, spi);
118 
119 	return strcmp(spi->modalias, drv->name) == 0;
120 }
121 
122 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
123 {
124 	const struct spi_device		*spi = to_spi_device(dev);
125 	int rc;
126 
127 	rc = acpi_device_uevent_modalias(dev, env);
128 	if (rc != -ENODEV)
129 		return rc;
130 
131 	add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
132 	return 0;
133 }
134 
135 #ifdef CONFIG_PM_SLEEP
136 static int spi_legacy_suspend(struct device *dev, pm_message_t message)
137 {
138 	int			value = 0;
139 	struct spi_driver	*drv = to_spi_driver(dev->driver);
140 
141 	/* suspend will stop irqs and dma; no more i/o */
142 	if (drv) {
143 		if (drv->suspend)
144 			value = drv->suspend(to_spi_device(dev), message);
145 		else
146 			dev_dbg(dev, "... can't suspend\n");
147 	}
148 	return value;
149 }
150 
151 static int spi_legacy_resume(struct device *dev)
152 {
153 	int			value = 0;
154 	struct spi_driver	*drv = to_spi_driver(dev->driver);
155 
156 	/* resume may restart the i/o queue */
157 	if (drv) {
158 		if (drv->resume)
159 			value = drv->resume(to_spi_device(dev));
160 		else
161 			dev_dbg(dev, "... can't resume\n");
162 	}
163 	return value;
164 }
165 
166 static int spi_pm_suspend(struct device *dev)
167 {
168 	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
169 
170 	if (pm)
171 		return pm_generic_suspend(dev);
172 	else
173 		return spi_legacy_suspend(dev, PMSG_SUSPEND);
174 }
175 
176 static int spi_pm_resume(struct device *dev)
177 {
178 	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
179 
180 	if (pm)
181 		return pm_generic_resume(dev);
182 	else
183 		return spi_legacy_resume(dev);
184 }
185 
186 static int spi_pm_freeze(struct device *dev)
187 {
188 	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
189 
190 	if (pm)
191 		return pm_generic_freeze(dev);
192 	else
193 		return spi_legacy_suspend(dev, PMSG_FREEZE);
194 }
195 
196 static int spi_pm_thaw(struct device *dev)
197 {
198 	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
199 
200 	if (pm)
201 		return pm_generic_thaw(dev);
202 	else
203 		return spi_legacy_resume(dev);
204 }
205 
206 static int spi_pm_poweroff(struct device *dev)
207 {
208 	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
209 
210 	if (pm)
211 		return pm_generic_poweroff(dev);
212 	else
213 		return spi_legacy_suspend(dev, PMSG_HIBERNATE);
214 }
215 
216 static int spi_pm_restore(struct device *dev)
217 {
218 	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
219 
220 	if (pm)
221 		return pm_generic_restore(dev);
222 	else
223 		return spi_legacy_resume(dev);
224 }
225 #else
226 #define spi_pm_suspend	NULL
227 #define spi_pm_resume	NULL
228 #define spi_pm_freeze	NULL
229 #define spi_pm_thaw	NULL
230 #define spi_pm_poweroff	NULL
231 #define spi_pm_restore	NULL
232 #endif
233 
234 static const struct dev_pm_ops spi_pm = {
235 	.suspend = spi_pm_suspend,
236 	.resume = spi_pm_resume,
237 	.freeze = spi_pm_freeze,
238 	.thaw = spi_pm_thaw,
239 	.poweroff = spi_pm_poweroff,
240 	.restore = spi_pm_restore,
241 	SET_RUNTIME_PM_OPS(
242 		pm_generic_runtime_suspend,
243 		pm_generic_runtime_resume,
244 		NULL
245 	)
246 };
247 
248 struct bus_type spi_bus_type = {
249 	.name		= "spi",
250 	.dev_groups	= spi_dev_groups,
251 	.match		= spi_match_device,
252 	.uevent		= spi_uevent,
253 	.pm		= &spi_pm,
254 };
255 EXPORT_SYMBOL_GPL(spi_bus_type);
256 
257 
258 static int spi_drv_probe(struct device *dev)
259 {
260 	const struct spi_driver		*sdrv = to_spi_driver(dev->driver);
261 	int ret;
262 
263 	ret = of_clk_set_defaults(dev->of_node, false);
264 	if (ret)
265 		return ret;
266 
267 	acpi_dev_pm_attach(dev, true);
268 	ret = sdrv->probe(to_spi_device(dev));
269 	if (ret)
270 		acpi_dev_pm_detach(dev, true);
271 
272 	return ret;
273 }
274 
275 static int spi_drv_remove(struct device *dev)
276 {
277 	const struct spi_driver		*sdrv = to_spi_driver(dev->driver);
278 	int ret;
279 
280 	ret = sdrv->remove(to_spi_device(dev));
281 	acpi_dev_pm_detach(dev, true);
282 
283 	return ret;
284 }
285 
286 static void spi_drv_shutdown(struct device *dev)
287 {
288 	const struct spi_driver		*sdrv = to_spi_driver(dev->driver);
289 
290 	sdrv->shutdown(to_spi_device(dev));
291 }
292 
293 /**
294  * spi_register_driver - register a SPI driver
295  * @sdrv: the driver to register
296  * Context: can sleep
297  */
298 int spi_register_driver(struct spi_driver *sdrv)
299 {
300 	sdrv->driver.bus = &spi_bus_type;
301 	if (sdrv->probe)
302 		sdrv->driver.probe = spi_drv_probe;
303 	if (sdrv->remove)
304 		sdrv->driver.remove = spi_drv_remove;
305 	if (sdrv->shutdown)
306 		sdrv->driver.shutdown = spi_drv_shutdown;
307 	return driver_register(&sdrv->driver);
308 }
309 EXPORT_SYMBOL_GPL(spi_register_driver);
310 
311 /*-------------------------------------------------------------------------*/
312 
313 /* SPI devices should normally not be created by SPI device drivers; that
314  * would make them board-specific.  Similarly with SPI master drivers.
315  * Device registration normally goes into like arch/.../mach.../board-YYY.c
316  * with other readonly (flashable) information about mainboard devices.
317  */
318 
319 struct boardinfo {
320 	struct list_head	list;
321 	struct spi_board_info	board_info;
322 };
323 
324 static LIST_HEAD(board_list);
325 static LIST_HEAD(spi_master_list);
326 
327 /*
328  * Used to protect add/del opertion for board_info list and
329  * spi_master list, and their matching process
330  */
331 static DEFINE_MUTEX(board_lock);
332 
333 /**
334  * spi_alloc_device - Allocate a new SPI device
335  * @master: Controller to which device is connected
336  * Context: can sleep
337  *
338  * Allows a driver to allocate and initialize a spi_device without
339  * registering it immediately.  This allows a driver to directly
340  * fill the spi_device with device parameters before calling
341  * spi_add_device() on it.
342  *
343  * Caller is responsible to call spi_add_device() on the returned
344  * spi_device structure to add it to the SPI master.  If the caller
345  * needs to discard the spi_device without adding it, then it should
346  * call spi_dev_put() on it.
347  *
348  * Returns a pointer to the new device, or NULL.
349  */
350 struct spi_device *spi_alloc_device(struct spi_master *master)
351 {
352 	struct spi_device	*spi;
353 
354 	if (!spi_master_get(master))
355 		return NULL;
356 
357 	spi = kzalloc(sizeof(*spi), GFP_KERNEL);
358 	if (!spi) {
359 		spi_master_put(master);
360 		return NULL;
361 	}
362 
363 	spi->master = master;
364 	spi->dev.parent = &master->dev;
365 	spi->dev.bus = &spi_bus_type;
366 	spi->dev.release = spidev_release;
367 	spi->cs_gpio = -ENOENT;
368 	device_initialize(&spi->dev);
369 	return spi;
370 }
371 EXPORT_SYMBOL_GPL(spi_alloc_device);
372 
373 static void spi_dev_set_name(struct spi_device *spi)
374 {
375 	struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
376 
377 	if (adev) {
378 		dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
379 		return;
380 	}
381 
382 	dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
383 		     spi->chip_select);
384 }
385 
386 static int spi_dev_check(struct device *dev, void *data)
387 {
388 	struct spi_device *spi = to_spi_device(dev);
389 	struct spi_device *new_spi = data;
390 
391 	if (spi->master == new_spi->master &&
392 	    spi->chip_select == new_spi->chip_select)
393 		return -EBUSY;
394 	return 0;
395 }
396 
397 /**
398  * spi_add_device - Add spi_device allocated with spi_alloc_device
399  * @spi: spi_device to register
400  *
401  * Companion function to spi_alloc_device.  Devices allocated with
402  * spi_alloc_device can be added onto the spi bus with this function.
403  *
404  * Returns 0 on success; negative errno on failure
405  */
406 int spi_add_device(struct spi_device *spi)
407 {
408 	static DEFINE_MUTEX(spi_add_lock);
409 	struct spi_master *master = spi->master;
410 	struct device *dev = master->dev.parent;
411 	int status;
412 
413 	/* Chipselects are numbered 0..max; validate. */
414 	if (spi->chip_select >= master->num_chipselect) {
415 		dev_err(dev, "cs%d >= max %d\n",
416 			spi->chip_select,
417 			master->num_chipselect);
418 		return -EINVAL;
419 	}
420 
421 	/* Set the bus ID string */
422 	spi_dev_set_name(spi);
423 
424 	/* We need to make sure there's no other device with this
425 	 * chipselect **BEFORE** we call setup(), else we'll trash
426 	 * its configuration.  Lock against concurrent add() calls.
427 	 */
428 	mutex_lock(&spi_add_lock);
429 
430 	status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
431 	if (status) {
432 		dev_err(dev, "chipselect %d already in use\n",
433 				spi->chip_select);
434 		goto done;
435 	}
436 
437 	if (master->cs_gpios)
438 		spi->cs_gpio = master->cs_gpios[spi->chip_select];
439 
440 	/* Drivers may modify this initial i/o setup, but will
441 	 * normally rely on the device being setup.  Devices
442 	 * using SPI_CS_HIGH can't coexist well otherwise...
443 	 */
444 	status = spi_setup(spi);
445 	if (status < 0) {
446 		dev_err(dev, "can't setup %s, status %d\n",
447 				dev_name(&spi->dev), status);
448 		goto done;
449 	}
450 
451 	/* Device may be bound to an active driver when this returns */
452 	status = device_add(&spi->dev);
453 	if (status < 0)
454 		dev_err(dev, "can't add %s, status %d\n",
455 				dev_name(&spi->dev), status);
456 	else
457 		dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
458 
459 done:
460 	mutex_unlock(&spi_add_lock);
461 	return status;
462 }
463 EXPORT_SYMBOL_GPL(spi_add_device);
464 
465 /**
466  * spi_new_device - instantiate one new SPI device
467  * @master: Controller to which device is connected
468  * @chip: Describes the SPI device
469  * Context: can sleep
470  *
471  * On typical mainboards, this is purely internal; and it's not needed
472  * after board init creates the hard-wired devices.  Some development
473  * platforms may not be able to use spi_register_board_info though, and
474  * this is exported so that for example a USB or parport based adapter
475  * driver could add devices (which it would learn about out-of-band).
476  *
477  * Returns the new device, or NULL.
478  */
479 struct spi_device *spi_new_device(struct spi_master *master,
480 				  struct spi_board_info *chip)
481 {
482 	struct spi_device	*proxy;
483 	int			status;
484 
485 	/* NOTE:  caller did any chip->bus_num checks necessary.
486 	 *
487 	 * Also, unless we change the return value convention to use
488 	 * error-or-pointer (not NULL-or-pointer), troubleshootability
489 	 * suggests syslogged diagnostics are best here (ugh).
490 	 */
491 
492 	proxy = spi_alloc_device(master);
493 	if (!proxy)
494 		return NULL;
495 
496 	WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
497 
498 	proxy->chip_select = chip->chip_select;
499 	proxy->max_speed_hz = chip->max_speed_hz;
500 	proxy->mode = chip->mode;
501 	proxy->irq = chip->irq;
502 	strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
503 	proxy->dev.platform_data = (void *) chip->platform_data;
504 	proxy->controller_data = chip->controller_data;
505 	proxy->controller_state = NULL;
506 
507 	status = spi_add_device(proxy);
508 	if (status < 0) {
509 		spi_dev_put(proxy);
510 		return NULL;
511 	}
512 
513 	return proxy;
514 }
515 EXPORT_SYMBOL_GPL(spi_new_device);
516 
517 static void spi_match_master_to_boardinfo(struct spi_master *master,
518 				struct spi_board_info *bi)
519 {
520 	struct spi_device *dev;
521 
522 	if (master->bus_num != bi->bus_num)
523 		return;
524 
525 	dev = spi_new_device(master, bi);
526 	if (!dev)
527 		dev_err(master->dev.parent, "can't create new device for %s\n",
528 			bi->modalias);
529 }
530 
531 /**
532  * spi_register_board_info - register SPI devices for a given board
533  * @info: array of chip descriptors
534  * @n: how many descriptors are provided
535  * Context: can sleep
536  *
537  * Board-specific early init code calls this (probably during arch_initcall)
538  * with segments of the SPI device table.  Any device nodes are created later,
539  * after the relevant parent SPI controller (bus_num) is defined.  We keep
540  * this table of devices forever, so that reloading a controller driver will
541  * not make Linux forget about these hard-wired devices.
542  *
543  * Other code can also call this, e.g. a particular add-on board might provide
544  * SPI devices through its expansion connector, so code initializing that board
545  * would naturally declare its SPI devices.
546  *
547  * The board info passed can safely be __initdata ... but be careful of
548  * any embedded pointers (platform_data, etc), they're copied as-is.
549  */
550 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
551 {
552 	struct boardinfo *bi;
553 	int i;
554 
555 	bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
556 	if (!bi)
557 		return -ENOMEM;
558 
559 	for (i = 0; i < n; i++, bi++, info++) {
560 		struct spi_master *master;
561 
562 		memcpy(&bi->board_info, info, sizeof(*info));
563 		mutex_lock(&board_lock);
564 		list_add_tail(&bi->list, &board_list);
565 		list_for_each_entry(master, &spi_master_list, list)
566 			spi_match_master_to_boardinfo(master, &bi->board_info);
567 		mutex_unlock(&board_lock);
568 	}
569 
570 	return 0;
571 }
572 
573 /*-------------------------------------------------------------------------*/
574 
575 static void spi_set_cs(struct spi_device *spi, bool enable)
576 {
577 	if (spi->mode & SPI_CS_HIGH)
578 		enable = !enable;
579 
580 	if (spi->cs_gpio >= 0)
581 		gpio_set_value(spi->cs_gpio, !enable);
582 	else if (spi->master->set_cs)
583 		spi->master->set_cs(spi, !enable);
584 }
585 
586 #ifdef CONFIG_HAS_DMA
587 static int spi_map_buf(struct spi_master *master, struct device *dev,
588 		       struct sg_table *sgt, void *buf, size_t len,
589 		       enum dma_data_direction dir)
590 {
591 	const bool vmalloced_buf = is_vmalloc_addr(buf);
592 	const int desc_len = vmalloced_buf ? PAGE_SIZE : master->max_dma_len;
593 	const int sgs = DIV_ROUND_UP(len, desc_len);
594 	struct page *vm_page;
595 	void *sg_buf;
596 	size_t min;
597 	int i, ret;
598 
599 	ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
600 	if (ret != 0)
601 		return ret;
602 
603 	for (i = 0; i < sgs; i++) {
604 		min = min_t(size_t, len, desc_len);
605 
606 		if (vmalloced_buf) {
607 			vm_page = vmalloc_to_page(buf);
608 			if (!vm_page) {
609 				sg_free_table(sgt);
610 				return -ENOMEM;
611 			}
612 			sg_buf = page_address(vm_page) +
613 				((size_t)buf & ~PAGE_MASK);
614 		} else {
615 			sg_buf = buf;
616 		}
617 
618 		sg_set_buf(&sgt->sgl[i], sg_buf, min);
619 
620 		buf += min;
621 		len -= min;
622 	}
623 
624 	ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
625 	if (!ret)
626 		ret = -ENOMEM;
627 	if (ret < 0) {
628 		sg_free_table(sgt);
629 		return ret;
630 	}
631 
632 	sgt->nents = ret;
633 
634 	return 0;
635 }
636 
637 static void spi_unmap_buf(struct spi_master *master, struct device *dev,
638 			  struct sg_table *sgt, enum dma_data_direction dir)
639 {
640 	if (sgt->orig_nents) {
641 		dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
642 		sg_free_table(sgt);
643 	}
644 }
645 
646 static int __spi_map_msg(struct spi_master *master, struct spi_message *msg)
647 {
648 	struct device *tx_dev, *rx_dev;
649 	struct spi_transfer *xfer;
650 	int ret;
651 
652 	if (!master->can_dma)
653 		return 0;
654 
655 	tx_dev = master->dma_tx->device->dev;
656 	rx_dev = master->dma_rx->device->dev;
657 
658 	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
659 		if (!master->can_dma(master, msg->spi, xfer))
660 			continue;
661 
662 		if (xfer->tx_buf != NULL) {
663 			ret = spi_map_buf(master, tx_dev, &xfer->tx_sg,
664 					  (void *)xfer->tx_buf, xfer->len,
665 					  DMA_TO_DEVICE);
666 			if (ret != 0)
667 				return ret;
668 		}
669 
670 		if (xfer->rx_buf != NULL) {
671 			ret = spi_map_buf(master, rx_dev, &xfer->rx_sg,
672 					  xfer->rx_buf, xfer->len,
673 					  DMA_FROM_DEVICE);
674 			if (ret != 0) {
675 				spi_unmap_buf(master, tx_dev, &xfer->tx_sg,
676 					      DMA_TO_DEVICE);
677 				return ret;
678 			}
679 		}
680 	}
681 
682 	master->cur_msg_mapped = true;
683 
684 	return 0;
685 }
686 
687 static int spi_unmap_msg(struct spi_master *master, struct spi_message *msg)
688 {
689 	struct spi_transfer *xfer;
690 	struct device *tx_dev, *rx_dev;
691 
692 	if (!master->cur_msg_mapped || !master->can_dma)
693 		return 0;
694 
695 	tx_dev = master->dma_tx->device->dev;
696 	rx_dev = master->dma_rx->device->dev;
697 
698 	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
699 		if (!master->can_dma(master, msg->spi, xfer))
700 			continue;
701 
702 		spi_unmap_buf(master, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
703 		spi_unmap_buf(master, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
704 	}
705 
706 	return 0;
707 }
708 #else /* !CONFIG_HAS_DMA */
709 static inline int __spi_map_msg(struct spi_master *master,
710 				struct spi_message *msg)
711 {
712 	return 0;
713 }
714 
715 static inline int spi_unmap_msg(struct spi_master *master,
716 				struct spi_message *msg)
717 {
718 	return 0;
719 }
720 #endif /* !CONFIG_HAS_DMA */
721 
722 static int spi_map_msg(struct spi_master *master, struct spi_message *msg)
723 {
724 	struct spi_transfer *xfer;
725 	void *tmp;
726 	unsigned int max_tx, max_rx;
727 
728 	if (master->flags & (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX)) {
729 		max_tx = 0;
730 		max_rx = 0;
731 
732 		list_for_each_entry(xfer, &msg->transfers, transfer_list) {
733 			if ((master->flags & SPI_MASTER_MUST_TX) &&
734 			    !xfer->tx_buf)
735 				max_tx = max(xfer->len, max_tx);
736 			if ((master->flags & SPI_MASTER_MUST_RX) &&
737 			    !xfer->rx_buf)
738 				max_rx = max(xfer->len, max_rx);
739 		}
740 
741 		if (max_tx) {
742 			tmp = krealloc(master->dummy_tx, max_tx,
743 				       GFP_KERNEL | GFP_DMA);
744 			if (!tmp)
745 				return -ENOMEM;
746 			master->dummy_tx = tmp;
747 			memset(tmp, 0, max_tx);
748 		}
749 
750 		if (max_rx) {
751 			tmp = krealloc(master->dummy_rx, max_rx,
752 				       GFP_KERNEL | GFP_DMA);
753 			if (!tmp)
754 				return -ENOMEM;
755 			master->dummy_rx = tmp;
756 		}
757 
758 		if (max_tx || max_rx) {
759 			list_for_each_entry(xfer, &msg->transfers,
760 					    transfer_list) {
761 				if (!xfer->tx_buf)
762 					xfer->tx_buf = master->dummy_tx;
763 				if (!xfer->rx_buf)
764 					xfer->rx_buf = master->dummy_rx;
765 			}
766 		}
767 	}
768 
769 	return __spi_map_msg(master, msg);
770 }
771 
772 /*
773  * spi_transfer_one_message - Default implementation of transfer_one_message()
774  *
775  * This is a standard implementation of transfer_one_message() for
776  * drivers which impelment a transfer_one() operation.  It provides
777  * standard handling of delays and chip select management.
778  */
779 static int spi_transfer_one_message(struct spi_master *master,
780 				    struct spi_message *msg)
781 {
782 	struct spi_transfer *xfer;
783 	bool keep_cs = false;
784 	int ret = 0;
785 	int ms = 1;
786 
787 	spi_set_cs(msg->spi, true);
788 
789 	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
790 		trace_spi_transfer_start(msg, xfer);
791 
792 		reinit_completion(&master->xfer_completion);
793 
794 		ret = master->transfer_one(master, msg->spi, xfer);
795 		if (ret < 0) {
796 			dev_err(&msg->spi->dev,
797 				"SPI transfer failed: %d\n", ret);
798 			goto out;
799 		}
800 
801 		if (ret > 0) {
802 			ret = 0;
803 			ms = xfer->len * 8 * 1000 / xfer->speed_hz;
804 			ms += ms + 100; /* some tolerance */
805 
806 			ms = wait_for_completion_timeout(&master->xfer_completion,
807 							 msecs_to_jiffies(ms));
808 		}
809 
810 		if (ms == 0) {
811 			dev_err(&msg->spi->dev, "SPI transfer timed out\n");
812 			msg->status = -ETIMEDOUT;
813 		}
814 
815 		trace_spi_transfer_stop(msg, xfer);
816 
817 		if (msg->status != -EINPROGRESS)
818 			goto out;
819 
820 		if (xfer->delay_usecs)
821 			udelay(xfer->delay_usecs);
822 
823 		if (xfer->cs_change) {
824 			if (list_is_last(&xfer->transfer_list,
825 					 &msg->transfers)) {
826 				keep_cs = true;
827 			} else {
828 				spi_set_cs(msg->spi, false);
829 				udelay(10);
830 				spi_set_cs(msg->spi, true);
831 			}
832 		}
833 
834 		msg->actual_length += xfer->len;
835 	}
836 
837 out:
838 	if (ret != 0 || !keep_cs)
839 		spi_set_cs(msg->spi, false);
840 
841 	if (msg->status == -EINPROGRESS)
842 		msg->status = ret;
843 
844 	spi_finalize_current_message(master);
845 
846 	return ret;
847 }
848 
849 /**
850  * spi_finalize_current_transfer - report completion of a transfer
851  * @master: the master reporting completion
852  *
853  * Called by SPI drivers using the core transfer_one_message()
854  * implementation to notify it that the current interrupt driven
855  * transfer has finished and the next one may be scheduled.
856  */
857 void spi_finalize_current_transfer(struct spi_master *master)
858 {
859 	complete(&master->xfer_completion);
860 }
861 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
862 
863 /**
864  * spi_pump_messages - kthread work function which processes spi message queue
865  * @work: pointer to kthread work struct contained in the master struct
866  *
867  * This function checks if there is any spi message in the queue that
868  * needs processing and if so call out to the driver to initialize hardware
869  * and transfer each message.
870  *
871  */
872 static void spi_pump_messages(struct kthread_work *work)
873 {
874 	struct spi_master *master =
875 		container_of(work, struct spi_master, pump_messages);
876 	unsigned long flags;
877 	bool was_busy = false;
878 	int ret;
879 
880 	/* Lock queue and check for queue work */
881 	spin_lock_irqsave(&master->queue_lock, flags);
882 	if (list_empty(&master->queue) || !master->running) {
883 		if (!master->busy) {
884 			spin_unlock_irqrestore(&master->queue_lock, flags);
885 			return;
886 		}
887 		master->busy = false;
888 		spin_unlock_irqrestore(&master->queue_lock, flags);
889 		kfree(master->dummy_rx);
890 		master->dummy_rx = NULL;
891 		kfree(master->dummy_tx);
892 		master->dummy_tx = NULL;
893 		if (master->unprepare_transfer_hardware &&
894 		    master->unprepare_transfer_hardware(master))
895 			dev_err(&master->dev,
896 				"failed to unprepare transfer hardware\n");
897 		if (master->auto_runtime_pm) {
898 			pm_runtime_mark_last_busy(master->dev.parent);
899 			pm_runtime_put_autosuspend(master->dev.parent);
900 		}
901 		trace_spi_master_idle(master);
902 		return;
903 	}
904 
905 	/* Make sure we are not already running a message */
906 	if (master->cur_msg) {
907 		spin_unlock_irqrestore(&master->queue_lock, flags);
908 		return;
909 	}
910 	/* Extract head of queue */
911 	master->cur_msg =
912 		list_first_entry(&master->queue, struct spi_message, queue);
913 
914 	list_del_init(&master->cur_msg->queue);
915 	if (master->busy)
916 		was_busy = true;
917 	else
918 		master->busy = true;
919 	spin_unlock_irqrestore(&master->queue_lock, flags);
920 
921 	if (!was_busy && master->auto_runtime_pm) {
922 		ret = pm_runtime_get_sync(master->dev.parent);
923 		if (ret < 0) {
924 			dev_err(&master->dev, "Failed to power device: %d\n",
925 				ret);
926 			return;
927 		}
928 	}
929 
930 	if (!was_busy)
931 		trace_spi_master_busy(master);
932 
933 	if (!was_busy && master->prepare_transfer_hardware) {
934 		ret = master->prepare_transfer_hardware(master);
935 		if (ret) {
936 			dev_err(&master->dev,
937 				"failed to prepare transfer hardware\n");
938 
939 			if (master->auto_runtime_pm)
940 				pm_runtime_put(master->dev.parent);
941 			return;
942 		}
943 	}
944 
945 	trace_spi_message_start(master->cur_msg);
946 
947 	if (master->prepare_message) {
948 		ret = master->prepare_message(master, master->cur_msg);
949 		if (ret) {
950 			dev_err(&master->dev,
951 				"failed to prepare message: %d\n", ret);
952 			master->cur_msg->status = ret;
953 			spi_finalize_current_message(master);
954 			return;
955 		}
956 		master->cur_msg_prepared = true;
957 	}
958 
959 	ret = spi_map_msg(master, master->cur_msg);
960 	if (ret) {
961 		master->cur_msg->status = ret;
962 		spi_finalize_current_message(master);
963 		return;
964 	}
965 
966 	ret = master->transfer_one_message(master, master->cur_msg);
967 	if (ret) {
968 		dev_err(&master->dev,
969 			"failed to transfer one message from queue\n");
970 		return;
971 	}
972 }
973 
974 static int spi_init_queue(struct spi_master *master)
975 {
976 	struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
977 
978 	INIT_LIST_HEAD(&master->queue);
979 	spin_lock_init(&master->queue_lock);
980 
981 	master->running = false;
982 	master->busy = false;
983 
984 	init_kthread_worker(&master->kworker);
985 	master->kworker_task = kthread_run(kthread_worker_fn,
986 					   &master->kworker, "%s",
987 					   dev_name(&master->dev));
988 	if (IS_ERR(master->kworker_task)) {
989 		dev_err(&master->dev, "failed to create message pump task\n");
990 		return -ENOMEM;
991 	}
992 	init_kthread_work(&master->pump_messages, spi_pump_messages);
993 
994 	/*
995 	 * Master config will indicate if this controller should run the
996 	 * message pump with high (realtime) priority to reduce the transfer
997 	 * latency on the bus by minimising the delay between a transfer
998 	 * request and the scheduling of the message pump thread. Without this
999 	 * setting the message pump thread will remain at default priority.
1000 	 */
1001 	if (master->rt) {
1002 		dev_info(&master->dev,
1003 			"will run message pump with realtime priority\n");
1004 		sched_setscheduler(master->kworker_task, SCHED_FIFO, &param);
1005 	}
1006 
1007 	return 0;
1008 }
1009 
1010 /**
1011  * spi_get_next_queued_message() - called by driver to check for queued
1012  * messages
1013  * @master: the master to check for queued messages
1014  *
1015  * If there are more messages in the queue, the next message is returned from
1016  * this call.
1017  */
1018 struct spi_message *spi_get_next_queued_message(struct spi_master *master)
1019 {
1020 	struct spi_message *next;
1021 	unsigned long flags;
1022 
1023 	/* get a pointer to the next message, if any */
1024 	spin_lock_irqsave(&master->queue_lock, flags);
1025 	next = list_first_entry_or_null(&master->queue, struct spi_message,
1026 					queue);
1027 	spin_unlock_irqrestore(&master->queue_lock, flags);
1028 
1029 	return next;
1030 }
1031 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1032 
1033 /**
1034  * spi_finalize_current_message() - the current message is complete
1035  * @master: the master to return the message to
1036  *
1037  * Called by the driver to notify the core that the message in the front of the
1038  * queue is complete and can be removed from the queue.
1039  */
1040 void spi_finalize_current_message(struct spi_master *master)
1041 {
1042 	struct spi_message *mesg;
1043 	unsigned long flags;
1044 	int ret;
1045 
1046 	spin_lock_irqsave(&master->queue_lock, flags);
1047 	mesg = master->cur_msg;
1048 	master->cur_msg = NULL;
1049 
1050 	queue_kthread_work(&master->kworker, &master->pump_messages);
1051 	spin_unlock_irqrestore(&master->queue_lock, flags);
1052 
1053 	spi_unmap_msg(master, mesg);
1054 
1055 	if (master->cur_msg_prepared && master->unprepare_message) {
1056 		ret = master->unprepare_message(master, mesg);
1057 		if (ret) {
1058 			dev_err(&master->dev,
1059 				"failed to unprepare message: %d\n", ret);
1060 		}
1061 	}
1062 	master->cur_msg_prepared = false;
1063 
1064 	mesg->state = NULL;
1065 	if (mesg->complete)
1066 		mesg->complete(mesg->context);
1067 
1068 	trace_spi_message_done(mesg);
1069 }
1070 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1071 
1072 static int spi_start_queue(struct spi_master *master)
1073 {
1074 	unsigned long flags;
1075 
1076 	spin_lock_irqsave(&master->queue_lock, flags);
1077 
1078 	if (master->running || master->busy) {
1079 		spin_unlock_irqrestore(&master->queue_lock, flags);
1080 		return -EBUSY;
1081 	}
1082 
1083 	master->running = true;
1084 	master->cur_msg = NULL;
1085 	spin_unlock_irqrestore(&master->queue_lock, flags);
1086 
1087 	queue_kthread_work(&master->kworker, &master->pump_messages);
1088 
1089 	return 0;
1090 }
1091 
1092 static int spi_stop_queue(struct spi_master *master)
1093 {
1094 	unsigned long flags;
1095 	unsigned limit = 500;
1096 	int ret = 0;
1097 
1098 	spin_lock_irqsave(&master->queue_lock, flags);
1099 
1100 	/*
1101 	 * This is a bit lame, but is optimized for the common execution path.
1102 	 * A wait_queue on the master->busy could be used, but then the common
1103 	 * execution path (pump_messages) would be required to call wake_up or
1104 	 * friends on every SPI message. Do this instead.
1105 	 */
1106 	while ((!list_empty(&master->queue) || master->busy) && limit--) {
1107 		spin_unlock_irqrestore(&master->queue_lock, flags);
1108 		usleep_range(10000, 11000);
1109 		spin_lock_irqsave(&master->queue_lock, flags);
1110 	}
1111 
1112 	if (!list_empty(&master->queue) || master->busy)
1113 		ret = -EBUSY;
1114 	else
1115 		master->running = false;
1116 
1117 	spin_unlock_irqrestore(&master->queue_lock, flags);
1118 
1119 	if (ret) {
1120 		dev_warn(&master->dev,
1121 			 "could not stop message queue\n");
1122 		return ret;
1123 	}
1124 	return ret;
1125 }
1126 
1127 static int spi_destroy_queue(struct spi_master *master)
1128 {
1129 	int ret;
1130 
1131 	ret = spi_stop_queue(master);
1132 
1133 	/*
1134 	 * flush_kthread_worker will block until all work is done.
1135 	 * If the reason that stop_queue timed out is that the work will never
1136 	 * finish, then it does no good to call flush/stop thread, so
1137 	 * return anyway.
1138 	 */
1139 	if (ret) {
1140 		dev_err(&master->dev, "problem destroying queue\n");
1141 		return ret;
1142 	}
1143 
1144 	flush_kthread_worker(&master->kworker);
1145 	kthread_stop(master->kworker_task);
1146 
1147 	return 0;
1148 }
1149 
1150 /**
1151  * spi_queued_transfer - transfer function for queued transfers
1152  * @spi: spi device which is requesting transfer
1153  * @msg: spi message which is to handled is queued to driver queue
1154  */
1155 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1156 {
1157 	struct spi_master *master = spi->master;
1158 	unsigned long flags;
1159 
1160 	spin_lock_irqsave(&master->queue_lock, flags);
1161 
1162 	if (!master->running) {
1163 		spin_unlock_irqrestore(&master->queue_lock, flags);
1164 		return -ESHUTDOWN;
1165 	}
1166 	msg->actual_length = 0;
1167 	msg->status = -EINPROGRESS;
1168 
1169 	list_add_tail(&msg->queue, &master->queue);
1170 	if (!master->busy)
1171 		queue_kthread_work(&master->kworker, &master->pump_messages);
1172 
1173 	spin_unlock_irqrestore(&master->queue_lock, flags);
1174 	return 0;
1175 }
1176 
1177 static int spi_master_initialize_queue(struct spi_master *master)
1178 {
1179 	int ret;
1180 
1181 	master->transfer = spi_queued_transfer;
1182 	if (!master->transfer_one_message)
1183 		master->transfer_one_message = spi_transfer_one_message;
1184 
1185 	/* Initialize and start queue */
1186 	ret = spi_init_queue(master);
1187 	if (ret) {
1188 		dev_err(&master->dev, "problem initializing queue\n");
1189 		goto err_init_queue;
1190 	}
1191 	master->queued = true;
1192 	ret = spi_start_queue(master);
1193 	if (ret) {
1194 		dev_err(&master->dev, "problem starting queue\n");
1195 		goto err_start_queue;
1196 	}
1197 
1198 	return 0;
1199 
1200 err_start_queue:
1201 	spi_destroy_queue(master);
1202 err_init_queue:
1203 	return ret;
1204 }
1205 
1206 /*-------------------------------------------------------------------------*/
1207 
1208 #if defined(CONFIG_OF)
1209 /**
1210  * of_register_spi_devices() - Register child devices onto the SPI bus
1211  * @master:	Pointer to spi_master device
1212  *
1213  * Registers an spi_device for each child node of master node which has a 'reg'
1214  * property.
1215  */
1216 static void of_register_spi_devices(struct spi_master *master)
1217 {
1218 	struct spi_device *spi;
1219 	struct device_node *nc;
1220 	int rc;
1221 	u32 value;
1222 
1223 	if (!master->dev.of_node)
1224 		return;
1225 
1226 	for_each_available_child_of_node(master->dev.of_node, nc) {
1227 		/* Alloc an spi_device */
1228 		spi = spi_alloc_device(master);
1229 		if (!spi) {
1230 			dev_err(&master->dev, "spi_device alloc error for %s\n",
1231 				nc->full_name);
1232 			spi_dev_put(spi);
1233 			continue;
1234 		}
1235 
1236 		/* Select device driver */
1237 		if (of_modalias_node(nc, spi->modalias,
1238 				     sizeof(spi->modalias)) < 0) {
1239 			dev_err(&master->dev, "cannot find modalias for %s\n",
1240 				nc->full_name);
1241 			spi_dev_put(spi);
1242 			continue;
1243 		}
1244 
1245 		/* Device address */
1246 		rc = of_property_read_u32(nc, "reg", &value);
1247 		if (rc) {
1248 			dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
1249 				nc->full_name, rc);
1250 			spi_dev_put(spi);
1251 			continue;
1252 		}
1253 		spi->chip_select = value;
1254 
1255 		/* Mode (clock phase/polarity/etc.) */
1256 		if (of_find_property(nc, "spi-cpha", NULL))
1257 			spi->mode |= SPI_CPHA;
1258 		if (of_find_property(nc, "spi-cpol", NULL))
1259 			spi->mode |= SPI_CPOL;
1260 		if (of_find_property(nc, "spi-cs-high", NULL))
1261 			spi->mode |= SPI_CS_HIGH;
1262 		if (of_find_property(nc, "spi-3wire", NULL))
1263 			spi->mode |= SPI_3WIRE;
1264 		if (of_find_property(nc, "spi-lsb-first", NULL))
1265 			spi->mode |= SPI_LSB_FIRST;
1266 
1267 		/* Device DUAL/QUAD mode */
1268 		if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1269 			switch (value) {
1270 			case 1:
1271 				break;
1272 			case 2:
1273 				spi->mode |= SPI_TX_DUAL;
1274 				break;
1275 			case 4:
1276 				spi->mode |= SPI_TX_QUAD;
1277 				break;
1278 			default:
1279 				dev_warn(&master->dev,
1280 					 "spi-tx-bus-width %d not supported\n",
1281 					 value);
1282 				break;
1283 			}
1284 		}
1285 
1286 		if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1287 			switch (value) {
1288 			case 1:
1289 				break;
1290 			case 2:
1291 				spi->mode |= SPI_RX_DUAL;
1292 				break;
1293 			case 4:
1294 				spi->mode |= SPI_RX_QUAD;
1295 				break;
1296 			default:
1297 				dev_warn(&master->dev,
1298 					 "spi-rx-bus-width %d not supported\n",
1299 					 value);
1300 				break;
1301 			}
1302 		}
1303 
1304 		/* Device speed */
1305 		rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1306 		if (rc) {
1307 			dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
1308 				nc->full_name, rc);
1309 			spi_dev_put(spi);
1310 			continue;
1311 		}
1312 		spi->max_speed_hz = value;
1313 
1314 		/* IRQ */
1315 		spi->irq = irq_of_parse_and_map(nc, 0);
1316 
1317 		/* Store a pointer to the node in the device structure */
1318 		of_node_get(nc);
1319 		spi->dev.of_node = nc;
1320 
1321 		/* Register the new device */
1322 		request_module("%s%s", SPI_MODULE_PREFIX, spi->modalias);
1323 		rc = spi_add_device(spi);
1324 		if (rc) {
1325 			dev_err(&master->dev, "spi_device register error %s\n",
1326 				nc->full_name);
1327 			spi_dev_put(spi);
1328 		}
1329 
1330 	}
1331 }
1332 #else
1333 static void of_register_spi_devices(struct spi_master *master) { }
1334 #endif
1335 
1336 #ifdef CONFIG_ACPI
1337 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1338 {
1339 	struct spi_device *spi = data;
1340 
1341 	if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1342 		struct acpi_resource_spi_serialbus *sb;
1343 
1344 		sb = &ares->data.spi_serial_bus;
1345 		if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1346 			spi->chip_select = sb->device_selection;
1347 			spi->max_speed_hz = sb->connection_speed;
1348 
1349 			if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1350 				spi->mode |= SPI_CPHA;
1351 			if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1352 				spi->mode |= SPI_CPOL;
1353 			if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1354 				spi->mode |= SPI_CS_HIGH;
1355 		}
1356 	} else if (spi->irq < 0) {
1357 		struct resource r;
1358 
1359 		if (acpi_dev_resource_interrupt(ares, 0, &r))
1360 			spi->irq = r.start;
1361 	}
1362 
1363 	/* Always tell the ACPI core to skip this resource */
1364 	return 1;
1365 }
1366 
1367 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1368 				       void *data, void **return_value)
1369 {
1370 	struct spi_master *master = data;
1371 	struct list_head resource_list;
1372 	struct acpi_device *adev;
1373 	struct spi_device *spi;
1374 	int ret;
1375 
1376 	if (acpi_bus_get_device(handle, &adev))
1377 		return AE_OK;
1378 	if (acpi_bus_get_status(adev) || !adev->status.present)
1379 		return AE_OK;
1380 
1381 	spi = spi_alloc_device(master);
1382 	if (!spi) {
1383 		dev_err(&master->dev, "failed to allocate SPI device for %s\n",
1384 			dev_name(&adev->dev));
1385 		return AE_NO_MEMORY;
1386 	}
1387 
1388 	ACPI_COMPANION_SET(&spi->dev, adev);
1389 	spi->irq = -1;
1390 
1391 	INIT_LIST_HEAD(&resource_list);
1392 	ret = acpi_dev_get_resources(adev, &resource_list,
1393 				     acpi_spi_add_resource, spi);
1394 	acpi_dev_free_resource_list(&resource_list);
1395 
1396 	if (ret < 0 || !spi->max_speed_hz) {
1397 		spi_dev_put(spi);
1398 		return AE_OK;
1399 	}
1400 
1401 	adev->power.flags.ignore_parent = true;
1402 	strlcpy(spi->modalias, acpi_device_hid(adev), sizeof(spi->modalias));
1403 	if (spi_add_device(spi)) {
1404 		adev->power.flags.ignore_parent = false;
1405 		dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
1406 			dev_name(&adev->dev));
1407 		spi_dev_put(spi);
1408 	}
1409 
1410 	return AE_OK;
1411 }
1412 
1413 static void acpi_register_spi_devices(struct spi_master *master)
1414 {
1415 	acpi_status status;
1416 	acpi_handle handle;
1417 
1418 	handle = ACPI_HANDLE(master->dev.parent);
1419 	if (!handle)
1420 		return;
1421 
1422 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1423 				     acpi_spi_add_device, NULL,
1424 				     master, NULL);
1425 	if (ACPI_FAILURE(status))
1426 		dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
1427 }
1428 #else
1429 static inline void acpi_register_spi_devices(struct spi_master *master) {}
1430 #endif /* CONFIG_ACPI */
1431 
1432 static void spi_master_release(struct device *dev)
1433 {
1434 	struct spi_master *master;
1435 
1436 	master = container_of(dev, struct spi_master, dev);
1437 	kfree(master);
1438 }
1439 
1440 static struct class spi_master_class = {
1441 	.name		= "spi_master",
1442 	.owner		= THIS_MODULE,
1443 	.dev_release	= spi_master_release,
1444 };
1445 
1446 
1447 
1448 /**
1449  * spi_alloc_master - allocate SPI master controller
1450  * @dev: the controller, possibly using the platform_bus
1451  * @size: how much zeroed driver-private data to allocate; the pointer to this
1452  *	memory is in the driver_data field of the returned device,
1453  *	accessible with spi_master_get_devdata().
1454  * Context: can sleep
1455  *
1456  * This call is used only by SPI master controller drivers, which are the
1457  * only ones directly touching chip registers.  It's how they allocate
1458  * an spi_master structure, prior to calling spi_register_master().
1459  *
1460  * This must be called from context that can sleep.  It returns the SPI
1461  * master structure on success, else NULL.
1462  *
1463  * The caller is responsible for assigning the bus number and initializing
1464  * the master's methods before calling spi_register_master(); and (after errors
1465  * adding the device) calling spi_master_put() and kfree() to prevent a memory
1466  * leak.
1467  */
1468 struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
1469 {
1470 	struct spi_master	*master;
1471 
1472 	if (!dev)
1473 		return NULL;
1474 
1475 	master = kzalloc(size + sizeof(*master), GFP_KERNEL);
1476 	if (!master)
1477 		return NULL;
1478 
1479 	device_initialize(&master->dev);
1480 	master->bus_num = -1;
1481 	master->num_chipselect = 1;
1482 	master->dev.class = &spi_master_class;
1483 	master->dev.parent = get_device(dev);
1484 	spi_master_set_devdata(master, &master[1]);
1485 
1486 	return master;
1487 }
1488 EXPORT_SYMBOL_GPL(spi_alloc_master);
1489 
1490 #ifdef CONFIG_OF
1491 static int of_spi_register_master(struct spi_master *master)
1492 {
1493 	int nb, i, *cs;
1494 	struct device_node *np = master->dev.of_node;
1495 
1496 	if (!np)
1497 		return 0;
1498 
1499 	nb = of_gpio_named_count(np, "cs-gpios");
1500 	master->num_chipselect = max_t(int, nb, master->num_chipselect);
1501 
1502 	/* Return error only for an incorrectly formed cs-gpios property */
1503 	if (nb == 0 || nb == -ENOENT)
1504 		return 0;
1505 	else if (nb < 0)
1506 		return nb;
1507 
1508 	cs = devm_kzalloc(&master->dev,
1509 			  sizeof(int) * master->num_chipselect,
1510 			  GFP_KERNEL);
1511 	master->cs_gpios = cs;
1512 
1513 	if (!master->cs_gpios)
1514 		return -ENOMEM;
1515 
1516 	for (i = 0; i < master->num_chipselect; i++)
1517 		cs[i] = -ENOENT;
1518 
1519 	for (i = 0; i < nb; i++)
1520 		cs[i] = of_get_named_gpio(np, "cs-gpios", i);
1521 
1522 	return 0;
1523 }
1524 #else
1525 static int of_spi_register_master(struct spi_master *master)
1526 {
1527 	return 0;
1528 }
1529 #endif
1530 
1531 /**
1532  * spi_register_master - register SPI master controller
1533  * @master: initialized master, originally from spi_alloc_master()
1534  * Context: can sleep
1535  *
1536  * SPI master controllers connect to their drivers using some non-SPI bus,
1537  * such as the platform bus.  The final stage of probe() in that code
1538  * includes calling spi_register_master() to hook up to this SPI bus glue.
1539  *
1540  * SPI controllers use board specific (often SOC specific) bus numbers,
1541  * and board-specific addressing for SPI devices combines those numbers
1542  * with chip select numbers.  Since SPI does not directly support dynamic
1543  * device identification, boards need configuration tables telling which
1544  * chip is at which address.
1545  *
1546  * This must be called from context that can sleep.  It returns zero on
1547  * success, else a negative error code (dropping the master's refcount).
1548  * After a successful return, the caller is responsible for calling
1549  * spi_unregister_master().
1550  */
1551 int spi_register_master(struct spi_master *master)
1552 {
1553 	static atomic_t		dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
1554 	struct device		*dev = master->dev.parent;
1555 	struct boardinfo	*bi;
1556 	int			status = -ENODEV;
1557 	int			dynamic = 0;
1558 
1559 	if (!dev)
1560 		return -ENODEV;
1561 
1562 	status = of_spi_register_master(master);
1563 	if (status)
1564 		return status;
1565 
1566 	/* even if it's just one always-selected device, there must
1567 	 * be at least one chipselect
1568 	 */
1569 	if (master->num_chipselect == 0)
1570 		return -EINVAL;
1571 
1572 	if ((master->bus_num < 0) && master->dev.of_node)
1573 		master->bus_num = of_alias_get_id(master->dev.of_node, "spi");
1574 
1575 	/* convention:  dynamically assigned bus IDs count down from the max */
1576 	if (master->bus_num < 0) {
1577 		/* FIXME switch to an IDR based scheme, something like
1578 		 * I2C now uses, so we can't run out of "dynamic" IDs
1579 		 */
1580 		master->bus_num = atomic_dec_return(&dyn_bus_id);
1581 		dynamic = 1;
1582 	}
1583 
1584 	spin_lock_init(&master->bus_lock_spinlock);
1585 	mutex_init(&master->bus_lock_mutex);
1586 	master->bus_lock_flag = 0;
1587 	init_completion(&master->xfer_completion);
1588 	if (!master->max_dma_len)
1589 		master->max_dma_len = INT_MAX;
1590 
1591 	/* register the device, then userspace will see it.
1592 	 * registration fails if the bus ID is in use.
1593 	 */
1594 	dev_set_name(&master->dev, "spi%u", master->bus_num);
1595 	status = device_add(&master->dev);
1596 	if (status < 0)
1597 		goto done;
1598 	dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1599 			dynamic ? " (dynamic)" : "");
1600 
1601 	/* If we're using a queued driver, start the queue */
1602 	if (master->transfer)
1603 		dev_info(dev, "master is unqueued, this is deprecated\n");
1604 	else {
1605 		status = spi_master_initialize_queue(master);
1606 		if (status) {
1607 			device_del(&master->dev);
1608 			goto done;
1609 		}
1610 	}
1611 
1612 	mutex_lock(&board_lock);
1613 	list_add_tail(&master->list, &spi_master_list);
1614 	list_for_each_entry(bi, &board_list, list)
1615 		spi_match_master_to_boardinfo(master, &bi->board_info);
1616 	mutex_unlock(&board_lock);
1617 
1618 	/* Register devices from the device tree and ACPI */
1619 	of_register_spi_devices(master);
1620 	acpi_register_spi_devices(master);
1621 done:
1622 	return status;
1623 }
1624 EXPORT_SYMBOL_GPL(spi_register_master);
1625 
1626 static void devm_spi_unregister(struct device *dev, void *res)
1627 {
1628 	spi_unregister_master(*(struct spi_master **)res);
1629 }
1630 
1631 /**
1632  * dev_spi_register_master - register managed SPI master controller
1633  * @dev:    device managing SPI master
1634  * @master: initialized master, originally from spi_alloc_master()
1635  * Context: can sleep
1636  *
1637  * Register a SPI device as with spi_register_master() which will
1638  * automatically be unregister
1639  */
1640 int devm_spi_register_master(struct device *dev, struct spi_master *master)
1641 {
1642 	struct spi_master **ptr;
1643 	int ret;
1644 
1645 	ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
1646 	if (!ptr)
1647 		return -ENOMEM;
1648 
1649 	ret = spi_register_master(master);
1650 	if (!ret) {
1651 		*ptr = master;
1652 		devres_add(dev, ptr);
1653 	} else {
1654 		devres_free(ptr);
1655 	}
1656 
1657 	return ret;
1658 }
1659 EXPORT_SYMBOL_GPL(devm_spi_register_master);
1660 
1661 static int __unregister(struct device *dev, void *null)
1662 {
1663 	spi_unregister_device(to_spi_device(dev));
1664 	return 0;
1665 }
1666 
1667 /**
1668  * spi_unregister_master - unregister SPI master controller
1669  * @master: the master being unregistered
1670  * Context: can sleep
1671  *
1672  * This call is used only by SPI master controller drivers, which are the
1673  * only ones directly touching chip registers.
1674  *
1675  * This must be called from context that can sleep.
1676  */
1677 void spi_unregister_master(struct spi_master *master)
1678 {
1679 	int dummy;
1680 
1681 	if (master->queued) {
1682 		if (spi_destroy_queue(master))
1683 			dev_err(&master->dev, "queue remove failed\n");
1684 	}
1685 
1686 	mutex_lock(&board_lock);
1687 	list_del(&master->list);
1688 	mutex_unlock(&board_lock);
1689 
1690 	dummy = device_for_each_child(&master->dev, NULL, __unregister);
1691 	device_unregister(&master->dev);
1692 }
1693 EXPORT_SYMBOL_GPL(spi_unregister_master);
1694 
1695 int spi_master_suspend(struct spi_master *master)
1696 {
1697 	int ret;
1698 
1699 	/* Basically no-ops for non-queued masters */
1700 	if (!master->queued)
1701 		return 0;
1702 
1703 	ret = spi_stop_queue(master);
1704 	if (ret)
1705 		dev_err(&master->dev, "queue stop failed\n");
1706 
1707 	return ret;
1708 }
1709 EXPORT_SYMBOL_GPL(spi_master_suspend);
1710 
1711 int spi_master_resume(struct spi_master *master)
1712 {
1713 	int ret;
1714 
1715 	if (!master->queued)
1716 		return 0;
1717 
1718 	ret = spi_start_queue(master);
1719 	if (ret)
1720 		dev_err(&master->dev, "queue restart failed\n");
1721 
1722 	return ret;
1723 }
1724 EXPORT_SYMBOL_GPL(spi_master_resume);
1725 
1726 static int __spi_master_match(struct device *dev, const void *data)
1727 {
1728 	struct spi_master *m;
1729 	const u16 *bus_num = data;
1730 
1731 	m = container_of(dev, struct spi_master, dev);
1732 	return m->bus_num == *bus_num;
1733 }
1734 
1735 /**
1736  * spi_busnum_to_master - look up master associated with bus_num
1737  * @bus_num: the master's bus number
1738  * Context: can sleep
1739  *
1740  * This call may be used with devices that are registered after
1741  * arch init time.  It returns a refcounted pointer to the relevant
1742  * spi_master (which the caller must release), or NULL if there is
1743  * no such master registered.
1744  */
1745 struct spi_master *spi_busnum_to_master(u16 bus_num)
1746 {
1747 	struct device		*dev;
1748 	struct spi_master	*master = NULL;
1749 
1750 	dev = class_find_device(&spi_master_class, NULL, &bus_num,
1751 				__spi_master_match);
1752 	if (dev)
1753 		master = container_of(dev, struct spi_master, dev);
1754 	/* reference got in class_find_device */
1755 	return master;
1756 }
1757 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
1758 
1759 
1760 /*-------------------------------------------------------------------------*/
1761 
1762 /* Core methods for SPI master protocol drivers.  Some of the
1763  * other core methods are currently defined as inline functions.
1764  */
1765 
1766 /**
1767  * spi_setup - setup SPI mode and clock rate
1768  * @spi: the device whose settings are being modified
1769  * Context: can sleep, and no requests are queued to the device
1770  *
1771  * SPI protocol drivers may need to update the transfer mode if the
1772  * device doesn't work with its default.  They may likewise need
1773  * to update clock rates or word sizes from initial values.  This function
1774  * changes those settings, and must be called from a context that can sleep.
1775  * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
1776  * effect the next time the device is selected and data is transferred to
1777  * or from it.  When this function returns, the spi device is deselected.
1778  *
1779  * Note that this call will fail if the protocol driver specifies an option
1780  * that the underlying controller or its driver does not support.  For
1781  * example, not all hardware supports wire transfers using nine bit words,
1782  * LSB-first wire encoding, or active-high chipselects.
1783  */
1784 int spi_setup(struct spi_device *spi)
1785 {
1786 	unsigned	bad_bits, ugly_bits;
1787 	int		status = 0;
1788 
1789 	/* check mode to prevent that DUAL and QUAD set at the same time
1790 	 */
1791 	if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
1792 		((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
1793 		dev_err(&spi->dev,
1794 		"setup: can not select dual and quad at the same time\n");
1795 		return -EINVAL;
1796 	}
1797 	/* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
1798 	 */
1799 	if ((spi->mode & SPI_3WIRE) && (spi->mode &
1800 		(SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
1801 		return -EINVAL;
1802 	/* help drivers fail *cleanly* when they need options
1803 	 * that aren't supported with their current master
1804 	 */
1805 	bad_bits = spi->mode & ~spi->master->mode_bits;
1806 	ugly_bits = bad_bits &
1807 		    (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD);
1808 	if (ugly_bits) {
1809 		dev_warn(&spi->dev,
1810 			 "setup: ignoring unsupported mode bits %x\n",
1811 			 ugly_bits);
1812 		spi->mode &= ~ugly_bits;
1813 		bad_bits &= ~ugly_bits;
1814 	}
1815 	if (bad_bits) {
1816 		dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
1817 			bad_bits);
1818 		return -EINVAL;
1819 	}
1820 
1821 	if (!spi->bits_per_word)
1822 		spi->bits_per_word = 8;
1823 
1824 	if (!spi->max_speed_hz)
1825 		spi->max_speed_hz = spi->master->max_speed_hz;
1826 
1827 	if (spi->master->setup)
1828 		status = spi->master->setup(spi);
1829 
1830 	dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
1831 			(int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
1832 			(spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
1833 			(spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
1834 			(spi->mode & SPI_3WIRE) ? "3wire, " : "",
1835 			(spi->mode & SPI_LOOP) ? "loopback, " : "",
1836 			spi->bits_per_word, spi->max_speed_hz,
1837 			status);
1838 
1839 	return status;
1840 }
1841 EXPORT_SYMBOL_GPL(spi_setup);
1842 
1843 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
1844 {
1845 	struct spi_master *master = spi->master;
1846 	struct spi_transfer *xfer;
1847 	int w_size;
1848 
1849 	if (list_empty(&message->transfers))
1850 		return -EINVAL;
1851 
1852 	/* Half-duplex links include original MicroWire, and ones with
1853 	 * only one data pin like SPI_3WIRE (switches direction) or where
1854 	 * either MOSI or MISO is missing.  They can also be caused by
1855 	 * software limitations.
1856 	 */
1857 	if ((master->flags & SPI_MASTER_HALF_DUPLEX)
1858 			|| (spi->mode & SPI_3WIRE)) {
1859 		unsigned flags = master->flags;
1860 
1861 		list_for_each_entry(xfer, &message->transfers, transfer_list) {
1862 			if (xfer->rx_buf && xfer->tx_buf)
1863 				return -EINVAL;
1864 			if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
1865 				return -EINVAL;
1866 			if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
1867 				return -EINVAL;
1868 		}
1869 	}
1870 
1871 	/**
1872 	 * Set transfer bits_per_word and max speed as spi device default if
1873 	 * it is not set for this transfer.
1874 	 * Set transfer tx_nbits and rx_nbits as single transfer default
1875 	 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
1876 	 */
1877 	list_for_each_entry(xfer, &message->transfers, transfer_list) {
1878 		message->frame_length += xfer->len;
1879 		if (!xfer->bits_per_word)
1880 			xfer->bits_per_word = spi->bits_per_word;
1881 
1882 		if (!xfer->speed_hz)
1883 			xfer->speed_hz = spi->max_speed_hz;
1884 
1885 		if (master->max_speed_hz &&
1886 		    xfer->speed_hz > master->max_speed_hz)
1887 			xfer->speed_hz = master->max_speed_hz;
1888 
1889 		if (master->bits_per_word_mask) {
1890 			/* Only 32 bits fit in the mask */
1891 			if (xfer->bits_per_word > 32)
1892 				return -EINVAL;
1893 			if (!(master->bits_per_word_mask &
1894 					BIT(xfer->bits_per_word - 1)))
1895 				return -EINVAL;
1896 		}
1897 
1898 		/*
1899 		 * SPI transfer length should be multiple of SPI word size
1900 		 * where SPI word size should be power-of-two multiple
1901 		 */
1902 		if (xfer->bits_per_word <= 8)
1903 			w_size = 1;
1904 		else if (xfer->bits_per_word <= 16)
1905 			w_size = 2;
1906 		else
1907 			w_size = 4;
1908 
1909 		/* No partial transfers accepted */
1910 		if (xfer->len % w_size)
1911 			return -EINVAL;
1912 
1913 		if (xfer->speed_hz && master->min_speed_hz &&
1914 		    xfer->speed_hz < master->min_speed_hz)
1915 			return -EINVAL;
1916 
1917 		if (xfer->tx_buf && !xfer->tx_nbits)
1918 			xfer->tx_nbits = SPI_NBITS_SINGLE;
1919 		if (xfer->rx_buf && !xfer->rx_nbits)
1920 			xfer->rx_nbits = SPI_NBITS_SINGLE;
1921 		/* check transfer tx/rx_nbits:
1922 		 * 1. check the value matches one of single, dual and quad
1923 		 * 2. check tx/rx_nbits match the mode in spi_device
1924 		 */
1925 		if (xfer->tx_buf) {
1926 			if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
1927 				xfer->tx_nbits != SPI_NBITS_DUAL &&
1928 				xfer->tx_nbits != SPI_NBITS_QUAD)
1929 				return -EINVAL;
1930 			if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
1931 				!(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
1932 				return -EINVAL;
1933 			if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
1934 				!(spi->mode & SPI_TX_QUAD))
1935 				return -EINVAL;
1936 		}
1937 		/* check transfer rx_nbits */
1938 		if (xfer->rx_buf) {
1939 			if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
1940 				xfer->rx_nbits != SPI_NBITS_DUAL &&
1941 				xfer->rx_nbits != SPI_NBITS_QUAD)
1942 				return -EINVAL;
1943 			if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
1944 				!(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
1945 				return -EINVAL;
1946 			if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
1947 				!(spi->mode & SPI_RX_QUAD))
1948 				return -EINVAL;
1949 		}
1950 	}
1951 
1952 	message->status = -EINPROGRESS;
1953 
1954 	return 0;
1955 }
1956 
1957 static int __spi_async(struct spi_device *spi, struct spi_message *message)
1958 {
1959 	struct spi_master *master = spi->master;
1960 
1961 	message->spi = spi;
1962 
1963 	trace_spi_message_submit(message);
1964 
1965 	return master->transfer(spi, message);
1966 }
1967 
1968 /**
1969  * spi_async - asynchronous SPI transfer
1970  * @spi: device with which data will be exchanged
1971  * @message: describes the data transfers, including completion callback
1972  * Context: any (irqs may be blocked, etc)
1973  *
1974  * This call may be used in_irq and other contexts which can't sleep,
1975  * as well as from task contexts which can sleep.
1976  *
1977  * The completion callback is invoked in a context which can't sleep.
1978  * Before that invocation, the value of message->status is undefined.
1979  * When the callback is issued, message->status holds either zero (to
1980  * indicate complete success) or a negative error code.  After that
1981  * callback returns, the driver which issued the transfer request may
1982  * deallocate the associated memory; it's no longer in use by any SPI
1983  * core or controller driver code.
1984  *
1985  * Note that although all messages to a spi_device are handled in
1986  * FIFO order, messages may go to different devices in other orders.
1987  * Some device might be higher priority, or have various "hard" access
1988  * time requirements, for example.
1989  *
1990  * On detection of any fault during the transfer, processing of
1991  * the entire message is aborted, and the device is deselected.
1992  * Until returning from the associated message completion callback,
1993  * no other spi_message queued to that device will be processed.
1994  * (This rule applies equally to all the synchronous transfer calls,
1995  * which are wrappers around this core asynchronous primitive.)
1996  */
1997 int spi_async(struct spi_device *spi, struct spi_message *message)
1998 {
1999 	struct spi_master *master = spi->master;
2000 	int ret;
2001 	unsigned long flags;
2002 
2003 	ret = __spi_validate(spi, message);
2004 	if (ret != 0)
2005 		return ret;
2006 
2007 	spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2008 
2009 	if (master->bus_lock_flag)
2010 		ret = -EBUSY;
2011 	else
2012 		ret = __spi_async(spi, message);
2013 
2014 	spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2015 
2016 	return ret;
2017 }
2018 EXPORT_SYMBOL_GPL(spi_async);
2019 
2020 /**
2021  * spi_async_locked - version of spi_async with exclusive bus usage
2022  * @spi: device with which data will be exchanged
2023  * @message: describes the data transfers, including completion callback
2024  * Context: any (irqs may be blocked, etc)
2025  *
2026  * This call may be used in_irq and other contexts which can't sleep,
2027  * as well as from task contexts which can sleep.
2028  *
2029  * The completion callback is invoked in a context which can't sleep.
2030  * Before that invocation, the value of message->status is undefined.
2031  * When the callback is issued, message->status holds either zero (to
2032  * indicate complete success) or a negative error code.  After that
2033  * callback returns, the driver which issued the transfer request may
2034  * deallocate the associated memory; it's no longer in use by any SPI
2035  * core or controller driver code.
2036  *
2037  * Note that although all messages to a spi_device are handled in
2038  * FIFO order, messages may go to different devices in other orders.
2039  * Some device might be higher priority, or have various "hard" access
2040  * time requirements, for example.
2041  *
2042  * On detection of any fault during the transfer, processing of
2043  * the entire message is aborted, and the device is deselected.
2044  * Until returning from the associated message completion callback,
2045  * no other spi_message queued to that device will be processed.
2046  * (This rule applies equally to all the synchronous transfer calls,
2047  * which are wrappers around this core asynchronous primitive.)
2048  */
2049 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
2050 {
2051 	struct spi_master *master = spi->master;
2052 	int ret;
2053 	unsigned long flags;
2054 
2055 	ret = __spi_validate(spi, message);
2056 	if (ret != 0)
2057 		return ret;
2058 
2059 	spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2060 
2061 	ret = __spi_async(spi, message);
2062 
2063 	spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2064 
2065 	return ret;
2066 
2067 }
2068 EXPORT_SYMBOL_GPL(spi_async_locked);
2069 
2070 
2071 /*-------------------------------------------------------------------------*/
2072 
2073 /* Utility methods for SPI master protocol drivers, layered on
2074  * top of the core.  Some other utility methods are defined as
2075  * inline functions.
2076  */
2077 
2078 static void spi_complete(void *arg)
2079 {
2080 	complete(arg);
2081 }
2082 
2083 static int __spi_sync(struct spi_device *spi, struct spi_message *message,
2084 		      int bus_locked)
2085 {
2086 	DECLARE_COMPLETION_ONSTACK(done);
2087 	int status;
2088 	struct spi_master *master = spi->master;
2089 
2090 	message->complete = spi_complete;
2091 	message->context = &done;
2092 
2093 	if (!bus_locked)
2094 		mutex_lock(&master->bus_lock_mutex);
2095 
2096 	status = spi_async_locked(spi, message);
2097 
2098 	if (!bus_locked)
2099 		mutex_unlock(&master->bus_lock_mutex);
2100 
2101 	if (status == 0) {
2102 		wait_for_completion(&done);
2103 		status = message->status;
2104 	}
2105 	message->context = NULL;
2106 	return status;
2107 }
2108 
2109 /**
2110  * spi_sync - blocking/synchronous SPI data transfers
2111  * @spi: device with which data will be exchanged
2112  * @message: describes the data transfers
2113  * Context: can sleep
2114  *
2115  * This call may only be used from a context that may sleep.  The sleep
2116  * is non-interruptible, and has no timeout.  Low-overhead controller
2117  * drivers may DMA directly into and out of the message buffers.
2118  *
2119  * Note that the SPI device's chip select is active during the message,
2120  * and then is normally disabled between messages.  Drivers for some
2121  * frequently-used devices may want to minimize costs of selecting a chip,
2122  * by leaving it selected in anticipation that the next message will go
2123  * to the same chip.  (That may increase power usage.)
2124  *
2125  * Also, the caller is guaranteeing that the memory associated with the
2126  * message will not be freed before this call returns.
2127  *
2128  * It returns zero on success, else a negative error code.
2129  */
2130 int spi_sync(struct spi_device *spi, struct spi_message *message)
2131 {
2132 	return __spi_sync(spi, message, 0);
2133 }
2134 EXPORT_SYMBOL_GPL(spi_sync);
2135 
2136 /**
2137  * spi_sync_locked - version of spi_sync with exclusive bus usage
2138  * @spi: device with which data will be exchanged
2139  * @message: describes the data transfers
2140  * Context: can sleep
2141  *
2142  * This call may only be used from a context that may sleep.  The sleep
2143  * is non-interruptible, and has no timeout.  Low-overhead controller
2144  * drivers may DMA directly into and out of the message buffers.
2145  *
2146  * This call should be used by drivers that require exclusive access to the
2147  * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
2148  * be released by a spi_bus_unlock call when the exclusive access is over.
2149  *
2150  * It returns zero on success, else a negative error code.
2151  */
2152 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
2153 {
2154 	return __spi_sync(spi, message, 1);
2155 }
2156 EXPORT_SYMBOL_GPL(spi_sync_locked);
2157 
2158 /**
2159  * spi_bus_lock - obtain a lock for exclusive SPI bus usage
2160  * @master: SPI bus master that should be locked for exclusive bus access
2161  * Context: can sleep
2162  *
2163  * This call may only be used from a context that may sleep.  The sleep
2164  * is non-interruptible, and has no timeout.
2165  *
2166  * This call should be used by drivers that require exclusive access to the
2167  * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
2168  * exclusive access is over. Data transfer must be done by spi_sync_locked
2169  * and spi_async_locked calls when the SPI bus lock is held.
2170  *
2171  * It returns zero on success, else a negative error code.
2172  */
2173 int spi_bus_lock(struct spi_master *master)
2174 {
2175 	unsigned long flags;
2176 
2177 	mutex_lock(&master->bus_lock_mutex);
2178 
2179 	spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2180 	master->bus_lock_flag = 1;
2181 	spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2182 
2183 	/* mutex remains locked until spi_bus_unlock is called */
2184 
2185 	return 0;
2186 }
2187 EXPORT_SYMBOL_GPL(spi_bus_lock);
2188 
2189 /**
2190  * spi_bus_unlock - release the lock for exclusive SPI bus usage
2191  * @master: SPI bus master that was locked for exclusive bus access
2192  * Context: can sleep
2193  *
2194  * This call may only be used from a context that may sleep.  The sleep
2195  * is non-interruptible, and has no timeout.
2196  *
2197  * This call releases an SPI bus lock previously obtained by an spi_bus_lock
2198  * call.
2199  *
2200  * It returns zero on success, else a negative error code.
2201  */
2202 int spi_bus_unlock(struct spi_master *master)
2203 {
2204 	master->bus_lock_flag = 0;
2205 
2206 	mutex_unlock(&master->bus_lock_mutex);
2207 
2208 	return 0;
2209 }
2210 EXPORT_SYMBOL_GPL(spi_bus_unlock);
2211 
2212 /* portable code must never pass more than 32 bytes */
2213 #define	SPI_BUFSIZ	max(32, SMP_CACHE_BYTES)
2214 
2215 static u8	*buf;
2216 
2217 /**
2218  * spi_write_then_read - SPI synchronous write followed by read
2219  * @spi: device with which data will be exchanged
2220  * @txbuf: data to be written (need not be dma-safe)
2221  * @n_tx: size of txbuf, in bytes
2222  * @rxbuf: buffer into which data will be read (need not be dma-safe)
2223  * @n_rx: size of rxbuf, in bytes
2224  * Context: can sleep
2225  *
2226  * This performs a half duplex MicroWire style transaction with the
2227  * device, sending txbuf and then reading rxbuf.  The return value
2228  * is zero for success, else a negative errno status code.
2229  * This call may only be used from a context that may sleep.
2230  *
2231  * Parameters to this routine are always copied using a small buffer;
2232  * portable code should never use this for more than 32 bytes.
2233  * Performance-sensitive or bulk transfer code should instead use
2234  * spi_{async,sync}() calls with dma-safe buffers.
2235  */
2236 int spi_write_then_read(struct spi_device *spi,
2237 		const void *txbuf, unsigned n_tx,
2238 		void *rxbuf, unsigned n_rx)
2239 {
2240 	static DEFINE_MUTEX(lock);
2241 
2242 	int			status;
2243 	struct spi_message	message;
2244 	struct spi_transfer	x[2];
2245 	u8			*local_buf;
2246 
2247 	/* Use preallocated DMA-safe buffer if we can.  We can't avoid
2248 	 * copying here, (as a pure convenience thing), but we can
2249 	 * keep heap costs out of the hot path unless someone else is
2250 	 * using the pre-allocated buffer or the transfer is too large.
2251 	 */
2252 	if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
2253 		local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
2254 				    GFP_KERNEL | GFP_DMA);
2255 		if (!local_buf)
2256 			return -ENOMEM;
2257 	} else {
2258 		local_buf = buf;
2259 	}
2260 
2261 	spi_message_init(&message);
2262 	memset(x, 0, sizeof(x));
2263 	if (n_tx) {
2264 		x[0].len = n_tx;
2265 		spi_message_add_tail(&x[0], &message);
2266 	}
2267 	if (n_rx) {
2268 		x[1].len = n_rx;
2269 		spi_message_add_tail(&x[1], &message);
2270 	}
2271 
2272 	memcpy(local_buf, txbuf, n_tx);
2273 	x[0].tx_buf = local_buf;
2274 	x[1].rx_buf = local_buf + n_tx;
2275 
2276 	/* do the i/o */
2277 	status = spi_sync(spi, &message);
2278 	if (status == 0)
2279 		memcpy(rxbuf, x[1].rx_buf, n_rx);
2280 
2281 	if (x[0].tx_buf == buf)
2282 		mutex_unlock(&lock);
2283 	else
2284 		kfree(local_buf);
2285 
2286 	return status;
2287 }
2288 EXPORT_SYMBOL_GPL(spi_write_then_read);
2289 
2290 /*-------------------------------------------------------------------------*/
2291 
2292 static int __init spi_init(void)
2293 {
2294 	int	status;
2295 
2296 	buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
2297 	if (!buf) {
2298 		status = -ENOMEM;
2299 		goto err0;
2300 	}
2301 
2302 	status = bus_register(&spi_bus_type);
2303 	if (status < 0)
2304 		goto err1;
2305 
2306 	status = class_register(&spi_master_class);
2307 	if (status < 0)
2308 		goto err2;
2309 	return 0;
2310 
2311 err2:
2312 	bus_unregister(&spi_bus_type);
2313 err1:
2314 	kfree(buf);
2315 	buf = NULL;
2316 err0:
2317 	return status;
2318 }
2319 
2320 /* board_info is normally registered in arch_initcall(),
2321  * but even essential drivers wait till later
2322  *
2323  * REVISIT only boardinfo really needs static linking. the rest (device and
2324  * driver registration) _could_ be dynamically linked (modular) ... costs
2325  * include needing to have boardinfo data structures be much more public.
2326  */
2327 postcore_initcall(spi_init);
2328 
2329