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 queue_delayed_work(system_nrt_wq
, &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
);