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v3.15
 
  1/*
  2 *  linux/drivers/mmc/core/host.c
  3 *
  4 *  Copyright (C) 2003 Russell King, All Rights Reserved.
  5 *  Copyright (C) 2007-2008 Pierre Ossman
  6 *  Copyright (C) 2010 Linus Walleij
  7 *
  8 * This program is free software; you can redistribute it and/or modify
  9 * it under the terms of the GNU General Public License version 2 as
 10 * published by the Free Software Foundation.
 11 *
 12 *  MMC host class device management
 13 */
 14
 15#include <linux/device.h>
 16#include <linux/err.h>
 17#include <linux/idr.h>
 18#include <linux/of.h>
 19#include <linux/of_gpio.h>
 20#include <linux/pagemap.h>
 
 21#include <linux/export.h>
 22#include <linux/leds.h>
 23#include <linux/slab.h>
 24#include <linux/suspend.h>
 25
 26#include <linux/mmc/host.h>
 27#include <linux/mmc/card.h>
 28#include <linux/mmc/slot-gpio.h>
 29
 30#include "core.h"
 
 31#include "host.h"
 
 
 
 32
 33#define cls_dev_to_mmc_host(d)	container_of(d, struct mmc_host, class_dev)
 34
 35static void mmc_host_classdev_release(struct device *dev)
 
 
 
 36{
 37	struct mmc_host *host = cls_dev_to_mmc_host(dev);
 38	mutex_destroy(&host->slot.lock);
 39	kfree(host);
 40}
 41
 42static struct class mmc_host_class = {
 43	.name		= "mmc_host",
 44	.dev_release	= mmc_host_classdev_release,
 45};
 
 
 46
 47int mmc_register_host_class(void)
 48{
 49	return class_register(&mmc_host_class);
 
 
 50}
 51
 52void mmc_unregister_host_class(void)
 53{
 54	class_unregister(&mmc_host_class);
 
 
 55}
 56
 57static DEFINE_IDR(mmc_host_idr);
 58static DEFINE_SPINLOCK(mmc_host_lock);
 
 
 
 
 
 
 
 59
 60#ifdef CONFIG_MMC_CLKGATE
 61static ssize_t clkgate_delay_show(struct device *dev,
 62		struct device_attribute *attr, char *buf)
 63{
 64	struct mmc_host *host = cls_dev_to_mmc_host(dev);
 65	return snprintf(buf, PAGE_SIZE, "%lu\n", host->clkgate_delay);
 
 
 
 66}
 67
 68static ssize_t clkgate_delay_store(struct device *dev,
 69		struct device_attribute *attr, const char *buf, size_t count)
 70{
 71	struct mmc_host *host = cls_dev_to_mmc_host(dev);
 72	unsigned long flags, value;
 73
 74	if (kstrtoul(buf, 0, &value))
 75		return -EINVAL;
 76
 77	spin_lock_irqsave(&host->clk_lock, flags);
 78	host->clkgate_delay = value;
 79	spin_unlock_irqrestore(&host->clk_lock, flags);
 80	return count;
 81}
 82
 83/*
 84 * Enabling clock gating will make the core call out to the host
 85 * once up and once down when it performs a request or card operation
 86 * intermingled in any fashion. The driver will see this through
 87 * set_ios() operations with ios.clock field set to 0 to gate (disable)
 88 * the block clock, and to the old frequency to enable it again.
 89 */
 90static void mmc_host_clk_gate_delayed(struct mmc_host *host)
 91{
 92	unsigned long tick_ns;
 93	unsigned long freq = host->ios.clock;
 94	unsigned long flags;
 95
 96	if (!freq) {
 97		pr_debug("%s: frequency set to 0 in disable function, "
 98			 "this means the clock is already disabled.\n",
 99			 mmc_hostname(host));
100		return;
101	}
102	/*
103	 * New requests may have appeared while we were scheduling,
104	 * then there is no reason to delay the check before
105	 * clk_disable().
106	 */
107	spin_lock_irqsave(&host->clk_lock, flags);
108
109	/*
110	 * Delay n bus cycles (at least 8 from MMC spec) before attempting
111	 * to disable the MCI block clock. The reference count may have
112	 * gone up again after this delay due to rescheduling!
113	 */
114	if (!host->clk_requests) {
115		spin_unlock_irqrestore(&host->clk_lock, flags);
116		tick_ns = DIV_ROUND_UP(1000000000, freq);
117		ndelay(host->clk_delay * tick_ns);
118	} else {
119		/* New users appeared while waiting for this work */
120		spin_unlock_irqrestore(&host->clk_lock, flags);
121		return;
122	}
123	mutex_lock(&host->clk_gate_mutex);
124	spin_lock_irqsave(&host->clk_lock, flags);
125	if (!host->clk_requests) {
126		spin_unlock_irqrestore(&host->clk_lock, flags);
127		/* This will set host->ios.clock to 0 */
128		mmc_gate_clock(host);
129		spin_lock_irqsave(&host->clk_lock, flags);
130		pr_debug("%s: gated MCI clock\n", mmc_hostname(host));
131	}
132	spin_unlock_irqrestore(&host->clk_lock, flags);
133	mutex_unlock(&host->clk_gate_mutex);
134}
135
136/*
137 * Internal work. Work to disable the clock at some later point.
138 */
139static void mmc_host_clk_gate_work(struct work_struct *work)
140{
141	struct mmc_host *host = container_of(work, struct mmc_host,
142					      clk_gate_work.work);
143
144	mmc_host_clk_gate_delayed(host);
145}
146
147/**
148 *	mmc_host_clk_hold - ungate hardware MCI clocks
149 *	@host: host to ungate.
150 *
151 *	Makes sure the host ios.clock is restored to a non-zero value
152 *	past this call.	Increase clock reference count and ungate clock
153 *	if we're the first user.
154 */
155void mmc_host_clk_hold(struct mmc_host *host)
156{
157	unsigned long flags;
158
159	/* cancel any clock gating work scheduled by mmc_host_clk_release() */
160	cancel_delayed_work_sync(&host->clk_gate_work);
161	mutex_lock(&host->clk_gate_mutex);
162	spin_lock_irqsave(&host->clk_lock, flags);
163	if (host->clk_gated) {
164		spin_unlock_irqrestore(&host->clk_lock, flags);
165		mmc_ungate_clock(host);
166		spin_lock_irqsave(&host->clk_lock, flags);
167		pr_debug("%s: ungated MCI clock\n", mmc_hostname(host));
168	}
169	host->clk_requests++;
170	spin_unlock_irqrestore(&host->clk_lock, flags);
171	mutex_unlock(&host->clk_gate_mutex);
172}
173
174/**
175 *	mmc_host_may_gate_card - check if this card may be gated
176 *	@card: card to check.
177 */
178static bool mmc_host_may_gate_card(struct mmc_card *card)
179{
180	/* If there is no card we may gate it */
181	if (!card)
182		return true;
183	/*
184	 * Don't gate SDIO cards! These need to be clocked at all times
185	 * since they may be independent systems generating interrupts
186	 * and other events. The clock requests counter from the core will
187	 * go down to zero since the core does not need it, but we will not
188	 * gate the clock, because there is somebody out there that may still
189	 * be using it.
190	 */
191	return !(card->quirks & MMC_QUIRK_BROKEN_CLK_GATING);
192}
 
193
194/**
195 *	mmc_host_clk_release - gate off hardware MCI clocks
196 *	@host: host to gate.
197 *
198 *	Calls the host driver with ios.clock set to zero as often as possible
199 *	in order to gate off hardware MCI clocks. Decrease clock reference
200 *	count and schedule disabling of clock.
201 */
202void mmc_host_clk_release(struct mmc_host *host)
203{
204	unsigned long flags;
205
206	spin_lock_irqsave(&host->clk_lock, flags);
207	host->clk_requests--;
208	if (mmc_host_may_gate_card(host->card) &&
209	    !host->clk_requests)
210		schedule_delayed_work(&host->clk_gate_work,
211				      msecs_to_jiffies(host->clkgate_delay));
212	spin_unlock_irqrestore(&host->clk_lock, flags);
213}
 
214
215/**
216 *	mmc_host_clk_rate - get current clock frequency setting
217 *	@host: host to get the clock frequency for.
218 *
219 *	Returns current clock frequency regardless of gating.
220 */
221unsigned int mmc_host_clk_rate(struct mmc_host *host)
222{
223	unsigned long freq;
224	unsigned long flags;
 
 
 
225
226	spin_lock_irqsave(&host->clk_lock, flags);
227	if (host->clk_gated)
228		freq = host->clk_old;
229	else
230		freq = host->ios.clock;
231	spin_unlock_irqrestore(&host->clk_lock, flags);
232	return freq;
233}
 
234
235/**
236 *	mmc_host_clk_init - set up clock gating code
237 *	@host: host with potential clock to control
238 */
239static inline void mmc_host_clk_init(struct mmc_host *host)
240{
241	host->clk_requests = 0;
242	/* Hold MCI clock for 8 cycles by default */
243	host->clk_delay = 8;
244	/*
245	 * Default clock gating delay is 0ms to avoid wasting power.
246	 * This value can be tuned by writing into sysfs entry.
247	 */
248	host->clkgate_delay = 0;
249	host->clk_gated = false;
250	INIT_DELAYED_WORK(&host->clk_gate_work, mmc_host_clk_gate_work);
251	spin_lock_init(&host->clk_lock);
252	mutex_init(&host->clk_gate_mutex);
253}
254
255/**
256 *	mmc_host_clk_exit - shut down clock gating code
257 *	@host: host with potential clock to control
258 */
259static inline void mmc_host_clk_exit(struct mmc_host *host)
260{
261	/*
262	 * Wait for any outstanding gate and then make sure we're
263	 * ungated before exiting.
264	 */
265	if (cancel_delayed_work_sync(&host->clk_gate_work))
266		mmc_host_clk_gate_delayed(host);
267	if (host->clk_gated)
268		mmc_host_clk_hold(host);
269	/* There should be only one user now */
270	WARN_ON(host->clk_requests > 1);
271}
272
273static inline void mmc_host_clk_sysfs_init(struct mmc_host *host)
274{
275	host->clkgate_delay_attr.show = clkgate_delay_show;
276	host->clkgate_delay_attr.store = clkgate_delay_store;
277	sysfs_attr_init(&host->clkgate_delay_attr.attr);
278	host->clkgate_delay_attr.attr.name = "clkgate_delay";
279	host->clkgate_delay_attr.attr.mode = S_IRUGO | S_IWUSR;
280	if (device_create_file(&host->class_dev, &host->clkgate_delay_attr))
281		pr_err("%s: Failed to create clkgate_delay sysfs entry\n",
282				mmc_hostname(host));
283}
284#else
285
286static inline void mmc_host_clk_init(struct mmc_host *host)
287{
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
288}
289
290static inline void mmc_host_clk_exit(struct mmc_host *host)
291{
 
 
 
292}
293
294static inline void mmc_host_clk_sysfs_init(struct mmc_host *host)
 
295{
 
 
 
 
 
 
 
 
 
296}
297
298#endif
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
299
300/**
301 *	mmc_of_parse() - parse host's device-tree node
302 *	@host: host whose node should be parsed.
303 *
304 * To keep the rest of the MMC subsystem unaware of whether DT has been
305 * used to to instantiate and configure this host instance or not, we
306 * parse the properties and set respective generic mmc-host flags and
307 * parameters.
308 */
309int mmc_of_parse(struct mmc_host *host)
310{
311	struct device_node *np;
312	u32 bus_width;
313	bool explicit_inv_wp, gpio_inv_wp = false;
314	enum of_gpio_flags flags;
315	int len, ret, gpio;
316
317	if (!host->parent || !host->parent->of_node)
318		return 0;
319
320	np = host->parent->of_node;
321
322	/* "bus-width" is translated to MMC_CAP_*_BIT_DATA flags */
323	if (of_property_read_u32(np, "bus-width", &bus_width) < 0) {
324		dev_dbg(host->parent,
325			"\"bus-width\" property is missing, assuming 1 bit.\n");
326		bus_width = 1;
327	}
328
329	switch (bus_width) {
330	case 8:
331		host->caps |= MMC_CAP_8_BIT_DATA;
332		/* Hosts capable of 8-bit transfers can also do 4 bits */
333	case 4:
334		host->caps |= MMC_CAP_4_BIT_DATA;
335		break;
336	case 1:
337		break;
338	default:
339		dev_err(host->parent,
340			"Invalid \"bus-width\" value %u!\n", bus_width);
341		return -EINVAL;
342	}
343
344	/* f_max is obtained from the optional "max-frequency" property */
345	of_property_read_u32(np, "max-frequency", &host->f_max);
346
347	/*
348	 * Configure CD and WP pins. They are both by default active low to
349	 * match the SDHCI spec. If GPIOs are provided for CD and / or WP, the
350	 * mmc-gpio helpers are used to attach, configure and use them. If
351	 * polarity inversion is specified in DT, one of MMC_CAP2_CD_ACTIVE_HIGH
352	 * and MMC_CAP2_RO_ACTIVE_HIGH capability-2 flags is set. If the
353	 * "broken-cd" property is provided, the MMC_CAP_NEEDS_POLL capability
354	 * is set. If the "non-removable" property is found, the
355	 * MMC_CAP_NONREMOVABLE capability is set and no card-detection
356	 * configuration is performed.
357	 */
358
359	/* Parse Card Detection */
360	if (of_find_property(np, "non-removable", &len)) {
 
361		host->caps |= MMC_CAP_NONREMOVABLE;
362	} else {
363		bool explicit_inv_cd, gpio_inv_cd = false;
 
364
365		explicit_inv_cd = of_property_read_bool(np, "cd-inverted");
 
 
366
367		if (of_find_property(np, "broken-cd", &len))
368			host->caps |= MMC_CAP_NEEDS_POLL;
369
370		gpio = of_get_named_gpio_flags(np, "cd-gpios", 0, &flags);
371		if (gpio == -EPROBE_DEFER)
372			return gpio;
373		if (gpio_is_valid(gpio)) {
374			if (!(flags & OF_GPIO_ACTIVE_LOW))
375				gpio_inv_cd = true;
376
377			ret = mmc_gpio_request_cd(host, gpio, 0);
378			if (ret < 0) {
379				dev_err(host->parent,
380					"Failed to request CD GPIO #%d: %d!\n",
381					gpio, ret);
382				return ret;
383			} else {
384				dev_info(host->parent, "Got CD GPIO #%d.\n",
385					 gpio);
386			}
387		}
388
389		if (explicit_inv_cd ^ gpio_inv_cd)
390			host->caps2 |= MMC_CAP2_CD_ACTIVE_HIGH;
391	}
392
393	/* Parse Write Protection */
394	explicit_inv_wp = of_property_read_bool(np, "wp-inverted");
395
396	gpio = of_get_named_gpio_flags(np, "wp-gpios", 0, &flags);
397	if (gpio == -EPROBE_DEFER) {
398		ret = -EPROBE_DEFER;
399		goto out;
400	}
401	if (gpio_is_valid(gpio)) {
402		if (!(flags & OF_GPIO_ACTIVE_LOW))
403			gpio_inv_wp = true;
404
405		ret = mmc_gpio_request_ro(host, gpio);
406		if (ret < 0) {
407			dev_err(host->parent,
408				"Failed to request WP GPIO: %d!\n", ret);
409			goto out;
410		} else {
411				dev_info(host->parent, "Got WP GPIO #%d.\n",
412					 gpio);
413		}
414	}
415	if (explicit_inv_wp ^ gpio_inv_wp)
416		host->caps2 |= MMC_CAP2_RO_ACTIVE_HIGH;
417
418	if (of_find_property(np, "cap-sd-highspeed", &len))
 
 
 
 
 
 
 
 
 
419		host->caps |= MMC_CAP_SD_HIGHSPEED;
420	if (of_find_property(np, "cap-mmc-highspeed", &len))
421		host->caps |= MMC_CAP_MMC_HIGHSPEED;
422	if (of_find_property(np, "sd-uhs-sdr12", &len))
423		host->caps |= MMC_CAP_UHS_SDR12;
424	if (of_find_property(np, "sd-uhs-sdr25", &len))
425		host->caps |= MMC_CAP_UHS_SDR25;
426	if (of_find_property(np, "sd-uhs-sdr50", &len))
427		host->caps |= MMC_CAP_UHS_SDR50;
428	if (of_find_property(np, "sd-uhs-sdr104", &len))
429		host->caps |= MMC_CAP_UHS_SDR104;
430	if (of_find_property(np, "sd-uhs-ddr50", &len))
431		host->caps |= MMC_CAP_UHS_DDR50;
432	if (of_find_property(np, "cap-power-off-card", &len))
433		host->caps |= MMC_CAP_POWER_OFF_CARD;
434	if (of_find_property(np, "cap-sdio-irq", &len))
 
 
435		host->caps |= MMC_CAP_SDIO_IRQ;
436	if (of_find_property(np, "full-pwr-cycle", &len))
437		host->caps2 |= MMC_CAP2_FULL_PWR_CYCLE;
438	if (of_find_property(np, "keep-power-in-suspend", &len))
 
 
439		host->pm_caps |= MMC_PM_KEEP_POWER;
440	if (of_find_property(np, "enable-sdio-wakeup", &len))
 
441		host->pm_caps |= MMC_PM_WAKE_SDIO_IRQ;
442	if (of_find_property(np, "mmc-ddr-1_8v", &len))
 
 
443		host->caps |= MMC_CAP_1_8V_DDR;
444	if (of_find_property(np, "mmc-ddr-1_2v", &len))
445		host->caps |= MMC_CAP_1_2V_DDR;
446	if (of_find_property(np, "mmc-hs200-1_8v", &len))
447		host->caps2 |= MMC_CAP2_HS200_1_8V_SDR;
448	if (of_find_property(np, "mmc-hs200-1_2v", &len))
449		host->caps2 |= MMC_CAP2_HS200_1_2V_SDR;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
450
451	return 0;
 
 
 
 
 
 
452
453out:
454	mmc_gpio_free_cd(host);
455	return ret;
 
456}
457
458EXPORT_SYMBOL(mmc_of_parse);
459
460/**
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
461 *	mmc_alloc_host - initialise the per-host structure.
462 *	@extra: sizeof private data structure
463 *	@dev: pointer to host device model structure
464 *
465 *	Initialise the per-host structure.
466 */
467struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
468{
469	int err;
470	struct mmc_host *host;
 
471
472	host = kzalloc(sizeof(struct mmc_host) + extra, GFP_KERNEL);
473	if (!host)
474		return NULL;
475
476	/* scanning will be enabled when we're ready */
477	host->rescan_disable = 1;
478	idr_preload(GFP_KERNEL);
479	spin_lock(&mmc_host_lock);
480	err = idr_alloc(&mmc_host_idr, host, 0, 0, GFP_NOWAIT);
481	if (err >= 0)
482		host->index = err;
483	spin_unlock(&mmc_host_lock);
484	idr_preload_end();
485	if (err < 0)
486		goto free;
 
 
 
 
 
 
 
 
487
488	dev_set_name(&host->class_dev, "mmc%d", host->index);
 
489
490	host->parent = dev;
491	host->class_dev.parent = dev;
492	host->class_dev.class = &mmc_host_class;
493	device_initialize(&host->class_dev);
 
494
495	mmc_host_clk_init(host);
496
497	mutex_init(&host->slot.lock);
498	host->slot.cd_irq = -EINVAL;
499
500	spin_lock_init(&host->lock);
501	init_waitqueue_head(&host->wq);
502	INIT_DELAYED_WORK(&host->detect, mmc_rescan);
503#ifdef CONFIG_PM
504	host->pm_notify.notifier_call = mmc_pm_notify;
505#endif
506
507	/*
508	 * By default, hosts do not support SGIO or large requests.
509	 * They have to set these according to their abilities.
510	 */
511	host->max_segs = 1;
512	host->max_seg_size = PAGE_CACHE_SIZE;
513
514	host->max_req_size = PAGE_CACHE_SIZE;
515	host->max_blk_size = 512;
516	host->max_blk_count = PAGE_CACHE_SIZE / 512;
517
518	return host;
 
 
519
520free:
521	kfree(host);
522	return NULL;
523}
524
525EXPORT_SYMBOL(mmc_alloc_host);
526
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
527/**
528 *	mmc_add_host - initialise host hardware
529 *	@host: mmc host
530 *
531 *	Register the host with the driver model. The host must be
532 *	prepared to start servicing requests before this function
533 *	completes.
534 */
535int mmc_add_host(struct mmc_host *host)
536{
537	int err;
538
539	WARN_ON((host->caps & MMC_CAP_SDIO_IRQ) &&
540		!host->ops->enable_sdio_irq);
 
541
542	err = device_add(&host->class_dev);
543	if (err)
544		return err;
545
546	led_trigger_register_simple(dev_name(&host->class_dev), &host->led);
547
548#ifdef CONFIG_DEBUG_FS
549	mmc_add_host_debugfs(host);
550#endif
551	mmc_host_clk_sysfs_init(host);
552
553	mmc_start_host(host);
554	register_pm_notifier(&host->pm_notify);
555
556	return 0;
557}
558
559EXPORT_SYMBOL(mmc_add_host);
560
561/**
562 *	mmc_remove_host - remove host hardware
563 *	@host: mmc host
564 *
565 *	Unregister and remove all cards associated with this host,
566 *	and power down the MMC bus. No new requests will be issued
567 *	after this function has returned.
568 */
569void mmc_remove_host(struct mmc_host *host)
570{
571	unregister_pm_notifier(&host->pm_notify);
572	mmc_stop_host(host);
573
574#ifdef CONFIG_DEBUG_FS
575	mmc_remove_host_debugfs(host);
576#endif
577
578	device_del(&host->class_dev);
579
580	led_trigger_unregister_simple(host->led);
581
582	mmc_host_clk_exit(host);
583}
584
585EXPORT_SYMBOL(mmc_remove_host);
586
587/**
588 *	mmc_free_host - free the host structure
589 *	@host: mmc host
590 *
591 *	Free the host once all references to it have been dropped.
592 */
593void mmc_free_host(struct mmc_host *host)
594{
595	spin_lock(&mmc_host_lock);
596	idr_remove(&mmc_host_idr, host->index);
597	spin_unlock(&mmc_host_lock);
598
599	put_device(&host->class_dev);
600}
601
602EXPORT_SYMBOL(mmc_free_host);
v6.13.7
  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 *  linux/drivers/mmc/core/host.c
  4 *
  5 *  Copyright (C) 2003 Russell King, All Rights Reserved.
  6 *  Copyright (C) 2007-2008 Pierre Ossman
  7 *  Copyright (C) 2010 Linus Walleij
  8 *
 
 
 
 
  9 *  MMC host class device management
 10 */
 11
 12#include <linux/device.h>
 13#include <linux/err.h>
 14#include <linux/idr.h>
 15#include <linux/of.h>
 
 16#include <linux/pagemap.h>
 17#include <linux/pm_wakeup.h>
 18#include <linux/export.h>
 19#include <linux/leds.h>
 20#include <linux/slab.h>
 
 21
 22#include <linux/mmc/host.h>
 23#include <linux/mmc/card.h>
 24#include <linux/mmc/slot-gpio.h>
 25
 26#include "core.h"
 27#include "crypto.h"
 28#include "host.h"
 29#include "slot-gpio.h"
 30#include "pwrseq.h"
 31#include "sdio_ops.h"
 32
 33#define cls_dev_to_mmc_host(d)	container_of(d, struct mmc_host, class_dev)
 34
 35static DEFINE_IDA(mmc_host_ida);
 36
 37#ifdef CONFIG_PM_SLEEP
 38static int mmc_host_class_prepare(struct device *dev)
 39{
 40	struct mmc_host *host = cls_dev_to_mmc_host(dev);
 
 
 
 41
 42	/*
 43	 * It's safe to access the bus_ops pointer, as both userspace and the
 44	 * workqueue for detecting cards are frozen at this point.
 45	 */
 46	if (!host->bus_ops)
 47		return 0;
 48
 49	/* Validate conditions for system suspend. */
 50	if (host->bus_ops->pre_suspend)
 51		return host->bus_ops->pre_suspend(host);
 52
 53	return 0;
 54}
 55
 56static void mmc_host_class_complete(struct device *dev)
 57{
 58	struct mmc_host *host = cls_dev_to_mmc_host(dev);
 59
 60	_mmc_detect_change(host, 0, false);
 61}
 62
 63static const struct dev_pm_ops mmc_host_class_dev_pm_ops = {
 64	.prepare = mmc_host_class_prepare,
 65	.complete = mmc_host_class_complete,
 66};
 67
 68#define MMC_HOST_CLASS_DEV_PM_OPS (&mmc_host_class_dev_pm_ops)
 69#else
 70#define MMC_HOST_CLASS_DEV_PM_OPS NULL
 71#endif
 72
 73static void mmc_host_classdev_release(struct device *dev)
 
 
 74{
 75	struct mmc_host *host = cls_dev_to_mmc_host(dev);
 76	wakeup_source_unregister(host->ws);
 77	if (of_alias_get_id(host->parent->of_node, "mmc") < 0)
 78		ida_free(&mmc_host_ida, host->index);
 79	kfree(host);
 80}
 81
 82static int mmc_host_classdev_shutdown(struct device *dev)
 
 83{
 84	struct mmc_host *host = cls_dev_to_mmc_host(dev);
 
 
 
 
 85
 86	__mmc_stop_host(host);
 87	return 0;
 
 
 88}
 89
 90static const struct class mmc_host_class = {
 91	.name		= "mmc_host",
 92	.dev_release	= mmc_host_classdev_release,
 93	.shutdown_pre	= mmc_host_classdev_shutdown,
 94	.pm		= MMC_HOST_CLASS_DEV_PM_OPS,
 95};
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 96
 97int mmc_register_host_class(void)
 98{
 99	return class_register(&mmc_host_class);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
100}
101
102void mmc_unregister_host_class(void)
 
 
 
103{
104	class_unregister(&mmc_host_class);
 
 
 
105}
106
107/**
108 * mmc_retune_enable() - enter a transfer mode that requires retuning
109 * @host: host which should retune now
110 */
111void mmc_retune_enable(struct mmc_host *host)
112{
113	host->can_retune = 1;
114	if (host->retune_period)
115		mod_timer(&host->retune_timer,
116			  jiffies + host->retune_period * HZ);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
117}
118
119/*
120 * Pause re-tuning for a small set of operations.  The pause begins after the
121 * next command.
122 */
123void mmc_retune_pause(struct mmc_host *host)
124{
125	if (!host->retune_paused) {
126		host->retune_paused = 1;
127		mmc_retune_hold(host);
128	}
 
 
 
 
 
 
 
 
129}
130EXPORT_SYMBOL(mmc_retune_pause);
131
132void mmc_retune_unpause(struct mmc_host *host)
133{
134	if (host->retune_paused) {
135		host->retune_paused = 0;
136		mmc_retune_release(host);
137	}
 
 
 
 
 
 
 
 
 
 
 
 
 
138}
139EXPORT_SYMBOL(mmc_retune_unpause);
140
141/**
142 * mmc_retune_disable() - exit a transfer mode that requires retuning
143 * @host: host which should not retune anymore
144 *
145 * It is not meant for temporarily preventing retuning!
146 */
147void mmc_retune_disable(struct mmc_host *host)
148{
149	mmc_retune_unpause(host);
150	host->can_retune = 0;
151	del_timer_sync(&host->retune_timer);
152	mmc_retune_clear(host);
153}
154
155void mmc_retune_timer_stop(struct mmc_host *host)
156{
157	del_timer_sync(&host->retune_timer);
 
 
 
 
158}
159EXPORT_SYMBOL(mmc_retune_timer_stop);
160
161void mmc_retune_hold(struct mmc_host *host)
 
 
 
 
162{
163	if (!host->hold_retune)
164		host->retune_now = 1;
165	host->hold_retune += 1;
 
 
 
 
 
 
 
 
 
166}
167
168void mmc_retune_release(struct mmc_host *host)
 
 
 
 
169{
170	if (host->hold_retune)
171		host->hold_retune -= 1;
172	else
173		WARN_ON(1);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
174}
175EXPORT_SYMBOL(mmc_retune_release);
176
177int mmc_retune(struct mmc_host *host)
178{
179	bool return_to_hs400 = false;
180	int err;
181
182	if (host->retune_now)
183		host->retune_now = 0;
184	else
185		return 0;
186
187	if (!host->need_retune || host->doing_retune || !host->card)
188		return 0;
189
190	host->need_retune = 0;
191
192	host->doing_retune = 1;
193
194	if (host->ios.timing == MMC_TIMING_MMC_HS400) {
195		err = mmc_hs400_to_hs200(host->card);
196		if (err)
197			goto out;
198
199		return_to_hs400 = true;
200	}
201
202	err = mmc_execute_tuning(host->card);
203	if (err)
204		goto out;
205
206	if (return_to_hs400)
207		err = mmc_hs200_to_hs400(host->card);
208out:
209	host->doing_retune = 0;
210
211	return err;
212}
213
214static void mmc_retune_timer(struct timer_list *t)
215{
216	struct mmc_host *host = from_timer(host, t, retune_timer);
217
218	mmc_retune_needed(host);
219}
220
221static void mmc_of_parse_timing_phase(struct device *dev, const char *prop,
222				      struct mmc_clk_phase *phase)
223{
224	int degrees[2] = {0};
225	int rc;
226
227	rc = device_property_read_u32_array(dev, prop, degrees, 2);
228	phase->valid = !rc;
229	if (phase->valid) {
230		phase->in_deg = degrees[0];
231		phase->out_deg = degrees[1];
232	}
233}
234
235void
236mmc_of_parse_clk_phase(struct device *dev, struct mmc_clk_phase_map *map)
237{
238	mmc_of_parse_timing_phase(dev, "clk-phase-legacy",
239				  &map->phase[MMC_TIMING_LEGACY]);
240	mmc_of_parse_timing_phase(dev, "clk-phase-mmc-hs",
241				  &map->phase[MMC_TIMING_MMC_HS]);
242	mmc_of_parse_timing_phase(dev, "clk-phase-sd-hs",
243				  &map->phase[MMC_TIMING_SD_HS]);
244	mmc_of_parse_timing_phase(dev, "clk-phase-uhs-sdr12",
245				  &map->phase[MMC_TIMING_UHS_SDR12]);
246	mmc_of_parse_timing_phase(dev, "clk-phase-uhs-sdr25",
247				  &map->phase[MMC_TIMING_UHS_SDR25]);
248	mmc_of_parse_timing_phase(dev, "clk-phase-uhs-sdr50",
249				  &map->phase[MMC_TIMING_UHS_SDR50]);
250	mmc_of_parse_timing_phase(dev, "clk-phase-uhs-sdr104",
251				  &map->phase[MMC_TIMING_UHS_SDR104]);
252	mmc_of_parse_timing_phase(dev, "clk-phase-uhs-ddr50",
253				  &map->phase[MMC_TIMING_UHS_DDR50]);
254	mmc_of_parse_timing_phase(dev, "clk-phase-mmc-ddr52",
255				  &map->phase[MMC_TIMING_MMC_DDR52]);
256	mmc_of_parse_timing_phase(dev, "clk-phase-mmc-hs200",
257				  &map->phase[MMC_TIMING_MMC_HS200]);
258	mmc_of_parse_timing_phase(dev, "clk-phase-mmc-hs400",
259				  &map->phase[MMC_TIMING_MMC_HS400]);
260}
261EXPORT_SYMBOL(mmc_of_parse_clk_phase);
262
263/**
264 * mmc_of_parse() - parse host's device properties
265 * @host: host whose properties should be parsed.
266 *
267 * To keep the rest of the MMC subsystem unaware of whether DT has been
268 * used to instantiate and configure this host instance or not, we
269 * parse the properties and set respective generic mmc-host flags and
270 * parameters.
271 */
272int mmc_of_parse(struct mmc_host *host)
273{
274	struct device *dev = host->parent;
275	u32 bus_width, drv_type, cd_debounce_delay_ms;
276	int ret;
 
 
277
278	if (!dev || !dev_fwnode(dev))
279		return 0;
280
 
 
281	/* "bus-width" is translated to MMC_CAP_*_BIT_DATA flags */
282	if (device_property_read_u32(dev, "bus-width", &bus_width) < 0) {
283		dev_dbg(host->parent,
284			"\"bus-width\" property is missing, assuming 1 bit.\n");
285		bus_width = 1;
286	}
287
288	switch (bus_width) {
289	case 8:
290		host->caps |= MMC_CAP_8_BIT_DATA;
291		fallthrough;	/* Hosts capable of 8-bit can also do 4 bits */
292	case 4:
293		host->caps |= MMC_CAP_4_BIT_DATA;
294		break;
295	case 1:
296		break;
297	default:
298		dev_err(host->parent,
299			"Invalid \"bus-width\" value %u!\n", bus_width);
300		return -EINVAL;
301	}
302
303	/* f_max is obtained from the optional "max-frequency" property */
304	device_property_read_u32(dev, "max-frequency", &host->f_max);
305
306	/*
307	 * Configure CD and WP pins. They are both by default active low to
308	 * match the SDHCI spec. If GPIOs are provided for CD and / or WP, the
309	 * mmc-gpio helpers are used to attach, configure and use them. If
310	 * polarity inversion is specified in DT, one of MMC_CAP2_CD_ACTIVE_HIGH
311	 * and MMC_CAP2_RO_ACTIVE_HIGH capability-2 flags is set. If the
312	 * "broken-cd" property is provided, the MMC_CAP_NEEDS_POLL capability
313	 * is set. If the "non-removable" property is found, the
314	 * MMC_CAP_NONREMOVABLE capability is set and no card-detection
315	 * configuration is performed.
316	 */
317
318	/* Parse Card Detection */
319
320	if (device_property_read_bool(dev, "non-removable")) {
321		host->caps |= MMC_CAP_NONREMOVABLE;
322	} else {
323		if (device_property_read_bool(dev, "cd-inverted"))
324			host->caps2 |= MMC_CAP2_CD_ACTIVE_HIGH;
325
326		if (device_property_read_u32(dev, "cd-debounce-delay-ms",
327					     &cd_debounce_delay_ms))
328			cd_debounce_delay_ms = 200;
329
330		if (device_property_read_bool(dev, "broken-cd"))
331			host->caps |= MMC_CAP_NEEDS_POLL;
332
333		ret = mmc_gpiod_request_cd(host, "cd", 0, false,
334					   cd_debounce_delay_ms * 1000);
335		if (!ret)
336			dev_info(host->parent, "Got CD GPIO\n");
337		else if (ret != -ENOENT && ret != -ENOSYS)
338			return ret;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
339	}
340
341	/* Parse Write Protection */
 
 
 
 
 
 
 
 
 
 
342
343	if (device_property_read_bool(dev, "wp-inverted"))
 
 
 
 
 
 
 
 
 
 
344		host->caps2 |= MMC_CAP2_RO_ACTIVE_HIGH;
345
346	ret = mmc_gpiod_request_ro(host, "wp", 0, 0);
347	if (!ret)
348		dev_info(host->parent, "Got WP GPIO\n");
349	else if (ret != -ENOENT && ret != -ENOSYS)
350		return ret;
351
352	if (device_property_read_bool(dev, "disable-wp"))
353		host->caps2 |= MMC_CAP2_NO_WRITE_PROTECT;
354
355	if (device_property_read_bool(dev, "cap-sd-highspeed"))
356		host->caps |= MMC_CAP_SD_HIGHSPEED;
357	if (device_property_read_bool(dev, "cap-mmc-highspeed"))
358		host->caps |= MMC_CAP_MMC_HIGHSPEED;
359	if (device_property_read_bool(dev, "sd-uhs-sdr12"))
360		host->caps |= MMC_CAP_UHS_SDR12;
361	if (device_property_read_bool(dev, "sd-uhs-sdr25"))
362		host->caps |= MMC_CAP_UHS_SDR25;
363	if (device_property_read_bool(dev, "sd-uhs-sdr50"))
364		host->caps |= MMC_CAP_UHS_SDR50;
365	if (device_property_read_bool(dev, "sd-uhs-sdr104"))
366		host->caps |= MMC_CAP_UHS_SDR104;
367	if (device_property_read_bool(dev, "sd-uhs-ddr50"))
368		host->caps |= MMC_CAP_UHS_DDR50;
369	if (device_property_read_bool(dev, "cap-power-off-card"))
370		host->caps |= MMC_CAP_POWER_OFF_CARD;
371	if (device_property_read_bool(dev, "cap-mmc-hw-reset"))
372		host->caps |= MMC_CAP_HW_RESET;
373	if (device_property_read_bool(dev, "cap-sdio-irq"))
374		host->caps |= MMC_CAP_SDIO_IRQ;
375	if (device_property_read_bool(dev, "full-pwr-cycle"))
376		host->caps2 |= MMC_CAP2_FULL_PWR_CYCLE;
377	if (device_property_read_bool(dev, "full-pwr-cycle-in-suspend"))
378		host->caps2 |= MMC_CAP2_FULL_PWR_CYCLE_IN_SUSPEND;
379	if (device_property_read_bool(dev, "keep-power-in-suspend"))
380		host->pm_caps |= MMC_PM_KEEP_POWER;
381	if (device_property_read_bool(dev, "wakeup-source") ||
382	    device_property_read_bool(dev, "enable-sdio-wakeup")) /* legacy */
383		host->pm_caps |= MMC_PM_WAKE_SDIO_IRQ;
384	if (device_property_read_bool(dev, "mmc-ddr-3_3v"))
385		host->caps |= MMC_CAP_3_3V_DDR;
386	if (device_property_read_bool(dev, "mmc-ddr-1_8v"))
387		host->caps |= MMC_CAP_1_8V_DDR;
388	if (device_property_read_bool(dev, "mmc-ddr-1_2v"))
389		host->caps |= MMC_CAP_1_2V_DDR;
390	if (device_property_read_bool(dev, "mmc-hs200-1_8v"))
391		host->caps2 |= MMC_CAP2_HS200_1_8V_SDR;
392	if (device_property_read_bool(dev, "mmc-hs200-1_2v"))
393		host->caps2 |= MMC_CAP2_HS200_1_2V_SDR;
394	if (device_property_read_bool(dev, "mmc-hs400-1_8v"))
395		host->caps2 |= MMC_CAP2_HS400_1_8V | MMC_CAP2_HS200_1_8V_SDR;
396	if (device_property_read_bool(dev, "mmc-hs400-1_2v"))
397		host->caps2 |= MMC_CAP2_HS400_1_2V | MMC_CAP2_HS200_1_2V_SDR;
398	if (device_property_read_bool(dev, "mmc-hs400-enhanced-strobe"))
399		host->caps2 |= MMC_CAP2_HS400_ES;
400	if (device_property_read_bool(dev, "no-sdio"))
401		host->caps2 |= MMC_CAP2_NO_SDIO;
402	if (device_property_read_bool(dev, "no-sd"))
403		host->caps2 |= MMC_CAP2_NO_SD;
404	if (device_property_read_bool(dev, "no-mmc"))
405		host->caps2 |= MMC_CAP2_NO_MMC;
406	if (device_property_read_bool(dev, "no-mmc-hs400"))
407		host->caps2 &= ~(MMC_CAP2_HS400_1_8V | MMC_CAP2_HS400_1_2V |
408				 MMC_CAP2_HS400_ES);
409
410	/* Must be after "non-removable" check */
411	if (device_property_read_u32(dev, "fixed-emmc-driver-type", &drv_type) == 0) {
412		if (host->caps & MMC_CAP_NONREMOVABLE)
413			host->fixed_drv_type = drv_type;
414		else
415			dev_err(host->parent,
416				"can't use fixed driver type, media is removable\n");
417	}
418
419	host->dsr_req = !device_property_read_u32(dev, "dsr", &host->dsr);
420	if (host->dsr_req && (host->dsr & ~0xffff)) {
421		dev_err(host->parent,
422			"device tree specified broken value for DSR: 0x%x, ignoring\n",
423			host->dsr);
424		host->dsr_req = 0;
425	}
426
427	device_property_read_u32(dev, "post-power-on-delay-ms",
428				 &host->ios.power_delay_ms);
429
430	return mmc_pwrseq_alloc(host);
431}
432
433EXPORT_SYMBOL(mmc_of_parse);
434
435/**
436 * mmc_of_parse_voltage - return mask of supported voltages
437 * @host: host whose properties should be parsed.
438 * @mask: mask of voltages available for MMC/SD/SDIO
439 *
440 * Parse the "voltage-ranges" property, returning zero if it is not
441 * found, negative errno if the voltage-range specification is invalid,
442 * or one if the voltage-range is specified and successfully parsed.
443 */
444int mmc_of_parse_voltage(struct mmc_host *host, u32 *mask)
445{
446	const char *prop = "voltage-ranges";
447	struct device *dev = host->parent;
448	u32 *voltage_ranges;
449	int num_ranges, i;
450	int ret;
451
452	if (!device_property_present(dev, prop)) {
453		dev_dbg(dev, "%s unspecified\n", prop);
454		return 0;
455	}
456
457	ret = device_property_count_u32(dev, prop);
458	if (ret < 0)
459		return ret;
460
461	num_ranges = ret / 2;
462	if (!num_ranges) {
463		dev_err(dev, "%s empty\n", prop);
464		return -EINVAL;
465	}
466
467	voltage_ranges = kcalloc(2 * num_ranges, sizeof(*voltage_ranges), GFP_KERNEL);
468	if (!voltage_ranges)
469		return -ENOMEM;
470
471	ret = device_property_read_u32_array(dev, prop, voltage_ranges, 2 * num_ranges);
472	if (ret) {
473		kfree(voltage_ranges);
474		return ret;
475	}
476
477	for (i = 0; i < num_ranges; i++) {
478		const int j = i * 2;
479		u32 ocr_mask;
480
481		ocr_mask = mmc_vddrange_to_ocrmask(voltage_ranges[j + 0],
482						   voltage_ranges[j + 1]);
483		if (!ocr_mask) {
484			dev_err(dev, "range #%d in %s is invalid\n", i, prop);
485			kfree(voltage_ranges);
486			return -EINVAL;
487		}
488		*mask |= ocr_mask;
489	}
490
491	kfree(voltage_ranges);
492
493	return 1;
494}
495EXPORT_SYMBOL(mmc_of_parse_voltage);
496
497/**
498 * mmc_first_nonreserved_index() - get the first index that is not reserved
499 */
500static int mmc_first_nonreserved_index(void)
501{
502	int max;
503
504	max = of_alias_get_highest_id("mmc");
505	if (max < 0)
506		return 0;
507
508	return max + 1;
509}
510
511/**
512 *	mmc_alloc_host - initialise the per-host structure.
513 *	@extra: sizeof private data structure
514 *	@dev: pointer to host device model structure
515 *
516 *	Initialise the per-host structure.
517 */
518struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
519{
520	int index;
521	struct mmc_host *host;
522	int alias_id, min_idx, max_idx;
523
524	host = kzalloc(sizeof(struct mmc_host) + extra, GFP_KERNEL);
525	if (!host)
526		return NULL;
527
528	/* scanning will be enabled when we're ready */
529	host->rescan_disable = 1;
530
531	alias_id = of_alias_get_id(dev->of_node, "mmc");
532	if (alias_id >= 0) {
533		index = alias_id;
534	} else {
535		min_idx = mmc_first_nonreserved_index();
536		max_idx = 0;
537
538		index = ida_alloc_range(&mmc_host_ida, min_idx, max_idx - 1,
539					GFP_KERNEL);
540		if (index < 0) {
541			kfree(host);
542			return NULL;
543		}
544	}
545
546	host->index = index;
547
548	dev_set_name(&host->class_dev, "mmc%d", host->index);
549	host->ws = wakeup_source_register(NULL, dev_name(&host->class_dev));
550
551	host->parent = dev;
552	host->class_dev.parent = dev;
553	host->class_dev.class = &mmc_host_class;
554	device_initialize(&host->class_dev);
555	device_enable_async_suspend(&host->class_dev);
556
557	if (mmc_gpio_alloc(host)) {
558		put_device(&host->class_dev);
559		return NULL;
560	}
561
562	spin_lock_init(&host->lock);
563	init_waitqueue_head(&host->wq);
564	INIT_DELAYED_WORK(&host->detect, mmc_rescan);
565	INIT_WORK(&host->sdio_irq_work, sdio_irq_work);
566	timer_setup(&host->retune_timer, mmc_retune_timer, 0);
 
567
568	/*
569	 * By default, hosts do not support SGIO or large requests.
570	 * They have to set these according to their abilities.
571	 */
572	host->max_segs = 1;
573	host->max_seg_size = PAGE_SIZE;
574
575	host->max_req_size = PAGE_SIZE;
576	host->max_blk_size = 512;
577	host->max_blk_count = PAGE_SIZE / 512;
578
579	host->fixed_drv_type = -EINVAL;
580	host->ios.power_delay_ms = 10;
581	host->ios.power_mode = MMC_POWER_UNDEFINED;
582
583	return host;
 
 
584}
585
586EXPORT_SYMBOL(mmc_alloc_host);
587
588static void devm_mmc_host_release(struct device *dev, void *res)
589{
590	mmc_free_host(*(struct mmc_host **)res);
591}
592
593struct mmc_host *devm_mmc_alloc_host(struct device *dev, int extra)
594{
595	struct mmc_host **dr, *host;
596
597	dr = devres_alloc(devm_mmc_host_release, sizeof(*dr), GFP_KERNEL);
598	if (!dr)
599		return NULL;
600
601	host = mmc_alloc_host(extra, dev);
602	if (!host) {
603		devres_free(dr);
604		return NULL;
605	}
606
607	*dr = host;
608	devres_add(dev, dr);
609
610	return host;
611}
612EXPORT_SYMBOL(devm_mmc_alloc_host);
613
614static int mmc_validate_host_caps(struct mmc_host *host)
615{
616	struct device *dev = host->parent;
617	u32 caps = host->caps, caps2 = host->caps2;
618
619	if (caps & MMC_CAP_SDIO_IRQ && !host->ops->enable_sdio_irq) {
620		dev_warn(dev, "missing ->enable_sdio_irq() ops\n");
621		return -EINVAL;
622	}
623
624	if (caps2 & (MMC_CAP2_HS400_ES | MMC_CAP2_HS400) &&
625	    !(caps & MMC_CAP_8_BIT_DATA) && !(caps2 & MMC_CAP2_NO_MMC)) {
626		dev_warn(dev, "drop HS400 support since no 8-bit bus\n");
627		host->caps2 = caps2 & ~MMC_CAP2_HS400_ES & ~MMC_CAP2_HS400;
628	}
629
630	return 0;
631}
632
633/**
634 *	mmc_add_host - initialise host hardware
635 *	@host: mmc host
636 *
637 *	Register the host with the driver model. The host must be
638 *	prepared to start servicing requests before this function
639 *	completes.
640 */
641int mmc_add_host(struct mmc_host *host)
642{
643	int err;
644
645	err = mmc_validate_host_caps(host);
646	if (err)
647		return err;
648
649	err = device_add(&host->class_dev);
650	if (err)
651		return err;
652
653	led_trigger_register_simple(dev_name(&host->class_dev), &host->led);
654
 
655	mmc_add_host_debugfs(host);
 
 
656
657	mmc_start_host(host);
 
 
658	return 0;
659}
660
661EXPORT_SYMBOL(mmc_add_host);
662
663/**
664 *	mmc_remove_host - remove host hardware
665 *	@host: mmc host
666 *
667 *	Unregister and remove all cards associated with this host,
668 *	and power down the MMC bus. No new requests will be issued
669 *	after this function has returned.
670 */
671void mmc_remove_host(struct mmc_host *host)
672{
 
673	mmc_stop_host(host);
674
 
675	mmc_remove_host_debugfs(host);
 
676
677	device_del(&host->class_dev);
678
679	led_trigger_unregister_simple(host->led);
 
 
680}
681
682EXPORT_SYMBOL(mmc_remove_host);
683
684/**
685 *	mmc_free_host - free the host structure
686 *	@host: mmc host
687 *
688 *	Free the host once all references to it have been dropped.
689 */
690void mmc_free_host(struct mmc_host *host)
691{
692	cancel_delayed_work_sync(&host->detect);
693	mmc_pwrseq_free(host);
 
 
694	put_device(&host->class_dev);
695}
696
697EXPORT_SYMBOL(mmc_free_host);