2 * linux/drivers/mmc/core/host.c
4 * Copyright (C) 2003 Russell King, All Rights Reserved.
5 * Copyright (C) 2007-2008 Pierre Ossman
6 * Copyright (C) 2010 Linus Walleij
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.
12 * MMC host class device management
15 #include <linux/device.h>
16 #include <linux/err.h>
17 #include <linux/idr.h>
18 #include <linux/pagemap.h>
19 #include <linux/export.h>
20 #include <linux/leds.h>
21 #include <linux/slab.h>
22 #include <linux/suspend.h>
24 #include <linux/mmc/host.h>
25 #include <linux/mmc/card.h>
30 #define cls_dev_to_mmc_host(d) container_of(d, struct mmc_host, class_dev)
32 static void mmc_host_classdev_release(struct device *dev)
34 struct mmc_host *host = cls_dev_to_mmc_host(dev);
35 mutex_destroy(&host->slot.lock);
39 static struct class mmc_host_class = {
41 .dev_release = mmc_host_classdev_release,
44 int mmc_register_host_class(void)
46 return class_register(&mmc_host_class);
49 void mmc_unregister_host_class(void)
51 class_unregister(&mmc_host_class);
54 static DEFINE_IDR(mmc_host_idr);
55 static DEFINE_SPINLOCK(mmc_host_lock);
57 #ifdef CONFIG_MMC_CLKGATE
58 static ssize_t clkgate_delay_show(struct device *dev,
59 struct device_attribute *attr, char *buf)
61 struct mmc_host *host = cls_dev_to_mmc_host(dev);
62 return snprintf(buf, PAGE_SIZE, "%lu\n", host->clkgate_delay);
65 static ssize_t clkgate_delay_store(struct device *dev,
66 struct device_attribute *attr, const char *buf, size_t count)
68 struct mmc_host *host = cls_dev_to_mmc_host(dev);
69 unsigned long flags, value;
71 if (kstrtoul(buf, 0, &value))
74 spin_lock_irqsave(&host->clk_lock, flags);
75 host->clkgate_delay = value;
76 spin_unlock_irqrestore(&host->clk_lock, flags);
81 * Enabling clock gating will make the core call out to the host
82 * once up and once down when it performs a request or card operation
83 * intermingled in any fashion. The driver will see this through
84 * set_ios() operations with ios.clock field set to 0 to gate (disable)
85 * the block clock, and to the old frequency to enable it again.
87 static void mmc_host_clk_gate_delayed(struct mmc_host *host)
89 unsigned long tick_ns;
90 unsigned long freq = host->ios.clock;
94 pr_debug("%s: frequency set to 0 in disable function, "
95 "this means the clock is already disabled.\n",
100 * New requests may have appeared while we were scheduling,
101 * then there is no reason to delay the check before
104 spin_lock_irqsave(&host->clk_lock, flags);
107 * Delay n bus cycles (at least 8 from MMC spec) before attempting
108 * to disable the MCI block clock. The reference count may have
109 * gone up again after this delay due to rescheduling!
111 if (!host->clk_requests) {
112 spin_unlock_irqrestore(&host->clk_lock, flags);
113 tick_ns = DIV_ROUND_UP(1000000000, freq);
114 ndelay(host->clk_delay * tick_ns);
116 /* New users appeared while waiting for this work */
117 spin_unlock_irqrestore(&host->clk_lock, flags);
120 mutex_lock(&host->clk_gate_mutex);
121 spin_lock_irqsave(&host->clk_lock, flags);
122 if (!host->clk_requests) {
123 spin_unlock_irqrestore(&host->clk_lock, flags);
124 /* This will set host->ios.clock to 0 */
125 mmc_gate_clock(host);
126 spin_lock_irqsave(&host->clk_lock, flags);
127 pr_debug("%s: gated MCI clock\n", mmc_hostname(host));
129 spin_unlock_irqrestore(&host->clk_lock, flags);
130 mutex_unlock(&host->clk_gate_mutex);
134 * Internal work. Work to disable the clock at some later point.
136 static void mmc_host_clk_gate_work(struct work_struct *work)
138 struct mmc_host *host = container_of(work, struct mmc_host,
141 mmc_host_clk_gate_delayed(host);
145 * mmc_host_clk_hold - ungate hardware MCI clocks
146 * @host: host to ungate.
148 * Makes sure the host ios.clock is restored to a non-zero value
149 * past this call. Increase clock reference count and ungate clock
150 * if we're the first user.
152 void mmc_host_clk_hold(struct mmc_host *host)
156 /* cancel any clock gating work scheduled by mmc_host_clk_release() */
157 cancel_delayed_work_sync(&host->clk_gate_work);
158 mutex_lock(&host->clk_gate_mutex);
159 spin_lock_irqsave(&host->clk_lock, flags);
160 if (host->clk_gated) {
161 spin_unlock_irqrestore(&host->clk_lock, flags);
162 mmc_ungate_clock(host);
163 spin_lock_irqsave(&host->clk_lock, flags);
164 pr_debug("%s: ungated MCI clock\n", mmc_hostname(host));
166 host->clk_requests++;
167 spin_unlock_irqrestore(&host->clk_lock, flags);
168 mutex_unlock(&host->clk_gate_mutex);
172 * mmc_host_may_gate_card - check if this card may be gated
173 * @card: card to check.
175 static bool mmc_host_may_gate_card(struct mmc_card *card)
177 /* If there is no card we may gate it */
181 * Don't gate SDIO cards! These need to be clocked at all times
182 * since they may be independent systems generating interrupts
183 * and other events. The clock requests counter from the core will
184 * go down to zero since the core does not need it, but we will not
185 * gate the clock, because there is somebody out there that may still
188 return !(card->quirks & MMC_QUIRK_BROKEN_CLK_GATING);
192 * mmc_host_clk_release - gate off hardware MCI clocks
193 * @host: host to gate.
195 * Calls the host driver with ios.clock set to zero as often as possible
196 * in order to gate off hardware MCI clocks. Decrease clock reference
197 * count and schedule disabling of clock.
199 void mmc_host_clk_release(struct mmc_host *host)
203 spin_lock_irqsave(&host->clk_lock, flags);
204 host->clk_requests--;
205 if (mmc_host_may_gate_card(host->card) &&
207 schedule_delayed_work(&host->clk_gate_work,
208 msecs_to_jiffies(host->clkgate_delay));
209 spin_unlock_irqrestore(&host->clk_lock, flags);
213 * mmc_host_clk_rate - get current clock frequency setting
214 * @host: host to get the clock frequency for.
216 * Returns current clock frequency regardless of gating.
218 unsigned int mmc_host_clk_rate(struct mmc_host *host)
223 spin_lock_irqsave(&host->clk_lock, flags);
225 freq = host->clk_old;
227 freq = host->ios.clock;
228 spin_unlock_irqrestore(&host->clk_lock, flags);
233 * mmc_host_clk_init - set up clock gating code
234 * @host: host with potential clock to control
236 static inline void mmc_host_clk_init(struct mmc_host *host)
238 host->clk_requests = 0;
239 /* Hold MCI clock for 8 cycles by default */
242 * Default clock gating delay is 0ms to avoid wasting power.
243 * This value can be tuned by writing into sysfs entry.
245 host->clkgate_delay = 0;
246 host->clk_gated = false;
247 INIT_DELAYED_WORK(&host->clk_gate_work, mmc_host_clk_gate_work);
248 spin_lock_init(&host->clk_lock);
249 mutex_init(&host->clk_gate_mutex);
253 * mmc_host_clk_exit - shut down clock gating code
254 * @host: host with potential clock to control
256 static inline void mmc_host_clk_exit(struct mmc_host *host)
259 * Wait for any outstanding gate and then make sure we're
260 * ungated before exiting.
262 if (cancel_delayed_work_sync(&host->clk_gate_work))
263 mmc_host_clk_gate_delayed(host);
265 mmc_host_clk_hold(host);
266 /* There should be only one user now */
267 WARN_ON(host->clk_requests > 1);
270 static inline void mmc_host_clk_sysfs_init(struct mmc_host *host)
272 host->clkgate_delay_attr.show = clkgate_delay_show;
273 host->clkgate_delay_attr.store = clkgate_delay_store;
274 sysfs_attr_init(&host->clkgate_delay_attr.attr);
275 host->clkgate_delay_attr.attr.name = "clkgate_delay";
276 host->clkgate_delay_attr.attr.mode = S_IRUGO | S_IWUSR;
277 if (device_create_file(&host->class_dev, &host->clkgate_delay_attr))
278 pr_err("%s: Failed to create clkgate_delay sysfs entry\n",
283 static inline void mmc_host_clk_init(struct mmc_host *host)
287 static inline void mmc_host_clk_exit(struct mmc_host *host)
291 static inline void mmc_host_clk_sysfs_init(struct mmc_host *host)
298 * mmc_alloc_host - initialise the per-host structure.
299 * @extra: sizeof private data structure
300 * @dev: pointer to host device model structure
302 * Initialise the per-host structure.
304 struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
307 struct mmc_host *host;
309 if (!idr_pre_get(&mmc_host_idr, GFP_KERNEL))
312 host = kzalloc(sizeof(struct mmc_host) + extra, GFP_KERNEL);
316 /* scanning will be enabled when we're ready */
317 host->rescan_disable = 1;
318 spin_lock(&mmc_host_lock);
319 err = idr_get_new(&mmc_host_idr, host, &host->index);
320 spin_unlock(&mmc_host_lock);
324 dev_set_name(&host->class_dev, "mmc%d", host->index);
327 host->class_dev.parent = dev;
328 host->class_dev.class = &mmc_host_class;
329 device_initialize(&host->class_dev);
331 mmc_host_clk_init(host);
333 mutex_init(&host->slot.lock);
334 host->slot.cd_irq = -EINVAL;
336 spin_lock_init(&host->lock);
337 init_waitqueue_head(&host->wq);
338 INIT_DELAYED_WORK(&host->detect, mmc_rescan);
340 host->pm_notify.notifier_call = mmc_pm_notify;
344 * By default, hosts do not support SGIO or large requests.
345 * They have to set these according to their abilities.
348 host->max_seg_size = PAGE_CACHE_SIZE;
350 host->max_req_size = PAGE_CACHE_SIZE;
351 host->max_blk_size = 512;
352 host->max_blk_count = PAGE_CACHE_SIZE / 512;
361 EXPORT_SYMBOL(mmc_alloc_host);
364 * mmc_add_host - initialise host hardware
367 * Register the host with the driver model. The host must be
368 * prepared to start servicing requests before this function
371 int mmc_add_host(struct mmc_host *host)
375 WARN_ON((host->caps & MMC_CAP_SDIO_IRQ) &&
376 !host->ops->enable_sdio_irq);
378 err = device_add(&host->class_dev);
382 led_trigger_register_simple(dev_name(&host->class_dev), &host->led);
384 #ifdef CONFIG_DEBUG_FS
385 mmc_add_host_debugfs(host);
387 mmc_host_clk_sysfs_init(host);
389 mmc_start_host(host);
390 register_pm_notifier(&host->pm_notify);
395 EXPORT_SYMBOL(mmc_add_host);
398 * mmc_remove_host - remove host hardware
401 * Unregister and remove all cards associated with this host,
402 * and power down the MMC bus. No new requests will be issued
403 * after this function has returned.
405 void mmc_remove_host(struct mmc_host *host)
407 unregister_pm_notifier(&host->pm_notify);
410 #ifdef CONFIG_DEBUG_FS
411 mmc_remove_host_debugfs(host);
414 device_del(&host->class_dev);
416 led_trigger_unregister_simple(host->led);
418 mmc_host_clk_exit(host);
421 EXPORT_SYMBOL(mmc_remove_host);
424 * mmc_free_host - free the host structure
427 * Free the host once all references to it have been dropped.
429 void mmc_free_host(struct mmc_host *host)
431 spin_lock(&mmc_host_lock);
432 idr_remove(&mmc_host_idr, host->index);
433 spin_unlock(&mmc_host_lock);
435 put_device(&host->class_dev);
438 EXPORT_SYMBOL(mmc_free_host);