Merge tag 'v3.3.7' into 3.3/master
[zen-stable.git] / drivers / mmc / core / host.c
blobc3704e293a7b30d52c9cc1893da88a0e4844131b
1 /*
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>
27 #include "core.h"
28 #include "host.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 kfree(host);
38 static struct class mmc_host_class = {
39 .name = "mmc_host",
40 .dev_release = mmc_host_classdev_release,
43 int mmc_register_host_class(void)
45 return class_register(&mmc_host_class);
48 void mmc_unregister_host_class(void)
50 class_unregister(&mmc_host_class);
53 static DEFINE_IDR(mmc_host_idr);
54 static DEFINE_SPINLOCK(mmc_host_lock);
56 #ifdef CONFIG_MMC_CLKGATE
57 static ssize_t clkgate_delay_show(struct device *dev,
58 struct device_attribute *attr, char *buf)
60 struct mmc_host *host = cls_dev_to_mmc_host(dev);
61 return snprintf(buf, PAGE_SIZE, "%lu\n", host->clkgate_delay);
64 static ssize_t clkgate_delay_store(struct device *dev,
65 struct device_attribute *attr, const char *buf, size_t count)
67 struct mmc_host *host = cls_dev_to_mmc_host(dev);
68 unsigned long flags, value;
70 if (kstrtoul(buf, 0, &value))
71 return -EINVAL;
73 spin_lock_irqsave(&host->clk_lock, flags);
74 host->clkgate_delay = value;
75 spin_unlock_irqrestore(&host->clk_lock, flags);
76 return count;
80 * Enabling clock gating will make the core call out to the host
81 * once up and once down when it performs a request or card operation
82 * intermingled in any fashion. The driver will see this through
83 * set_ios() operations with ios.clock field set to 0 to gate (disable)
84 * the block clock, and to the old frequency to enable it again.
86 static void mmc_host_clk_gate_delayed(struct mmc_host *host)
88 unsigned long tick_ns;
89 unsigned long freq = host->ios.clock;
90 unsigned long flags;
92 if (!freq) {
93 pr_debug("%s: frequency set to 0 in disable function, "
94 "this means the clock is already disabled.\n",
95 mmc_hostname(host));
96 return;
99 * New requests may have appeared while we were scheduling,
100 * then there is no reason to delay the check before
101 * clk_disable().
103 spin_lock_irqsave(&host->clk_lock, flags);
106 * Delay n bus cycles (at least 8 from MMC spec) before attempting
107 * to disable the MCI block clock. The reference count may have
108 * gone up again after this delay due to rescheduling!
110 if (!host->clk_requests) {
111 spin_unlock_irqrestore(&host->clk_lock, flags);
112 tick_ns = DIV_ROUND_UP(1000000000, freq);
113 ndelay(host->clk_delay * tick_ns);
114 } else {
115 /* New users appeared while waiting for this work */
116 spin_unlock_irqrestore(&host->clk_lock, flags);
117 return;
119 mutex_lock(&host->clk_gate_mutex);
120 spin_lock_irqsave(&host->clk_lock, flags);
121 if (!host->clk_requests) {
122 spin_unlock_irqrestore(&host->clk_lock, flags);
123 /* This will set host->ios.clock to 0 */
124 mmc_gate_clock(host);
125 spin_lock_irqsave(&host->clk_lock, flags);
126 pr_debug("%s: gated MCI clock\n", mmc_hostname(host));
128 spin_unlock_irqrestore(&host->clk_lock, flags);
129 mutex_unlock(&host->clk_gate_mutex);
133 * Internal work. Work to disable the clock at some later point.
135 static void mmc_host_clk_gate_work(struct work_struct *work)
137 struct mmc_host *host = container_of(work, struct mmc_host,
138 clk_gate_work.work);
140 mmc_host_clk_gate_delayed(host);
144 * mmc_host_clk_hold - ungate hardware MCI clocks
145 * @host: host to ungate.
147 * Makes sure the host ios.clock is restored to a non-zero value
148 * past this call. Increase clock reference count and ungate clock
149 * if we're the first user.
151 void mmc_host_clk_hold(struct mmc_host *host)
153 unsigned long flags;
155 /* cancel any clock gating work scheduled by mmc_host_clk_release() */
156 cancel_delayed_work_sync(&host->clk_gate_work);
157 mutex_lock(&host->clk_gate_mutex);
158 spin_lock_irqsave(&host->clk_lock, flags);
159 if (host->clk_gated) {
160 spin_unlock_irqrestore(&host->clk_lock, flags);
161 mmc_ungate_clock(host);
162 spin_lock_irqsave(&host->clk_lock, flags);
163 pr_debug("%s: ungated MCI clock\n", mmc_hostname(host));
165 host->clk_requests++;
166 spin_unlock_irqrestore(&host->clk_lock, flags);
167 mutex_unlock(&host->clk_gate_mutex);
171 * mmc_host_may_gate_card - check if this card may be gated
172 * @card: card to check.
174 static bool mmc_host_may_gate_card(struct mmc_card *card)
176 /* If there is no card we may gate it */
177 if (!card)
178 return true;
180 * Don't gate SDIO cards! These need to be clocked at all times
181 * since they may be independent systems generating interrupts
182 * and other events. The clock requests counter from the core will
183 * go down to zero since the core does not need it, but we will not
184 * gate the clock, because there is somebody out there that may still
185 * be using it.
187 return !(card->quirks & MMC_QUIRK_BROKEN_CLK_GATING);
191 * mmc_host_clk_release - gate off hardware MCI clocks
192 * @host: host to gate.
194 * Calls the host driver with ios.clock set to zero as often as possible
195 * in order to gate off hardware MCI clocks. Decrease clock reference
196 * count and schedule disabling of clock.
198 void mmc_host_clk_release(struct mmc_host *host)
200 unsigned long flags;
202 spin_lock_irqsave(&host->clk_lock, flags);
203 host->clk_requests--;
204 if (mmc_host_may_gate_card(host->card) &&
205 !host->clk_requests)
206 queue_delayed_work(system_nrt_wq, &host->clk_gate_work,
207 msecs_to_jiffies(host->clkgate_delay));
208 spin_unlock_irqrestore(&host->clk_lock, flags);
212 * mmc_host_clk_rate - get current clock frequency setting
213 * @host: host to get the clock frequency for.
215 * Returns current clock frequency regardless of gating.
217 unsigned int mmc_host_clk_rate(struct mmc_host *host)
219 unsigned long freq;
220 unsigned long flags;
222 spin_lock_irqsave(&host->clk_lock, flags);
223 if (host->clk_gated)
224 freq = host->clk_old;
225 else
226 freq = host->ios.clock;
227 spin_unlock_irqrestore(&host->clk_lock, flags);
228 return freq;
232 * mmc_host_clk_init - set up clock gating code
233 * @host: host with potential clock to control
235 static inline void mmc_host_clk_init(struct mmc_host *host)
237 host->clk_requests = 0;
238 /* Hold MCI clock for 8 cycles by default */
239 host->clk_delay = 8;
241 * Default clock gating delay is 0ms to avoid wasting power.
242 * This value can be tuned by writing into sysfs entry.
244 host->clkgate_delay = 0;
245 host->clk_gated = false;
246 INIT_DELAYED_WORK(&host->clk_gate_work, mmc_host_clk_gate_work);
247 spin_lock_init(&host->clk_lock);
248 mutex_init(&host->clk_gate_mutex);
252 * mmc_host_clk_exit - shut down clock gating code
253 * @host: host with potential clock to control
255 static inline void mmc_host_clk_exit(struct mmc_host *host)
258 * Wait for any outstanding gate and then make sure we're
259 * ungated before exiting.
261 if (cancel_delayed_work_sync(&host->clk_gate_work))
262 mmc_host_clk_gate_delayed(host);
263 if (host->clk_gated)
264 mmc_host_clk_hold(host);
265 /* There should be only one user now */
266 WARN_ON(host->clk_requests > 1);
269 static inline void mmc_host_clk_sysfs_init(struct mmc_host *host)
271 host->clkgate_delay_attr.show = clkgate_delay_show;
272 host->clkgate_delay_attr.store = clkgate_delay_store;
273 sysfs_attr_init(&host->clkgate_delay_attr.attr);
274 host->clkgate_delay_attr.attr.name = "clkgate_delay";
275 host->clkgate_delay_attr.attr.mode = S_IRUGO | S_IWUSR;
276 if (device_create_file(&host->class_dev, &host->clkgate_delay_attr))
277 pr_err("%s: Failed to create clkgate_delay sysfs entry\n",
278 mmc_hostname(host));
280 #else
282 static inline void mmc_host_clk_init(struct mmc_host *host)
286 static inline void mmc_host_clk_exit(struct mmc_host *host)
290 static inline void mmc_host_clk_sysfs_init(struct mmc_host *host)
294 #endif
297 * mmc_alloc_host - initialise the per-host structure.
298 * @extra: sizeof private data structure
299 * @dev: pointer to host device model structure
301 * Initialise the per-host structure.
303 struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
305 int err;
306 struct mmc_host *host;
308 if (!idr_pre_get(&mmc_host_idr, GFP_KERNEL))
309 return NULL;
311 host = kzalloc(sizeof(struct mmc_host) + extra, GFP_KERNEL);
312 if (!host)
313 return NULL;
315 spin_lock(&mmc_host_lock);
316 err = idr_get_new(&mmc_host_idr, host, &host->index);
317 spin_unlock(&mmc_host_lock);
318 if (err)
319 goto free;
321 dev_set_name(&host->class_dev, "mmc%d", host->index);
323 host->parent = dev;
324 host->class_dev.parent = dev;
325 host->class_dev.class = &mmc_host_class;
326 device_initialize(&host->class_dev);
328 mmc_host_clk_init(host);
330 spin_lock_init(&host->lock);
331 init_waitqueue_head(&host->wq);
332 INIT_DELAYED_WORK(&host->detect, mmc_rescan);
333 INIT_DELAYED_WORK_DEFERRABLE(&host->disable, mmc_host_deeper_disable);
334 #ifdef CONFIG_PM
335 host->pm_notify.notifier_call = mmc_pm_notify;
336 #endif
339 * By default, hosts do not support SGIO or large requests.
340 * They have to set these according to their abilities.
342 host->max_segs = 1;
343 host->max_seg_size = PAGE_CACHE_SIZE;
345 host->max_req_size = PAGE_CACHE_SIZE;
346 host->max_blk_size = 512;
347 host->max_blk_count = PAGE_CACHE_SIZE / 512;
349 return host;
351 free:
352 kfree(host);
353 return NULL;
356 EXPORT_SYMBOL(mmc_alloc_host);
359 * mmc_add_host - initialise host hardware
360 * @host: mmc host
362 * Register the host with the driver model. The host must be
363 * prepared to start servicing requests before this function
364 * completes.
366 int mmc_add_host(struct mmc_host *host)
368 int err;
370 WARN_ON((host->caps & MMC_CAP_SDIO_IRQ) &&
371 !host->ops->enable_sdio_irq);
373 err = device_add(&host->class_dev);
374 if (err)
375 return err;
377 led_trigger_register_simple(dev_name(&host->class_dev), &host->led);
379 #ifdef CONFIG_DEBUG_FS
380 mmc_add_host_debugfs(host);
381 #endif
382 mmc_host_clk_sysfs_init(host);
384 mmc_start_host(host);
385 register_pm_notifier(&host->pm_notify);
387 return 0;
390 EXPORT_SYMBOL(mmc_add_host);
393 * mmc_remove_host - remove host hardware
394 * @host: mmc host
396 * Unregister and remove all cards associated with this host,
397 * and power down the MMC bus. No new requests will be issued
398 * after this function has returned.
400 void mmc_remove_host(struct mmc_host *host)
402 unregister_pm_notifier(&host->pm_notify);
403 mmc_stop_host(host);
405 #ifdef CONFIG_DEBUG_FS
406 mmc_remove_host_debugfs(host);
407 #endif
409 device_del(&host->class_dev);
411 led_trigger_unregister_simple(host->led);
413 mmc_host_clk_exit(host);
416 EXPORT_SYMBOL(mmc_remove_host);
419 * mmc_free_host - free the host structure
420 * @host: mmc host
422 * Free the host once all references to it have been dropped.
424 void mmc_free_host(struct mmc_host *host)
426 spin_lock(&mmc_host_lock);
427 idr_remove(&mmc_host_idr, host->index);
428 spin_unlock(&mmc_host_lock);
430 put_device(&host->class_dev);
433 EXPORT_SYMBOL(mmc_free_host);