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
);
38 static struct class mmc_host_class
= {
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 millisecs\n",
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
);
78 pr_info("%s: clock gate delay set to %lu ms\n",
79 mmc_hostname(host
), value
);
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.
90 static void mmc_host_clk_gate_delayed(struct mmc_host
*host
)
92 unsigned long tick_ns
;
93 unsigned long freq
= host
->ios
.clock
;
97 pr_debug("%s: frequency set to 0 in disable function, "
98 "this means the clock is already disabled.\n",
103 * New requests may have appeared while we were scheduling,
104 * then there is no reason to delay the check before
107 spin_lock_irqsave(&host
->clk_lock
, flags
);
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!
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
);
119 /* New users appeared while waiting for this work */
120 spin_unlock_irqrestore(&host
->clk_lock
, flags
);
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
));
132 spin_unlock_irqrestore(&host
->clk_lock
, flags
);
133 mutex_unlock(&host
->clk_gate_mutex
);
137 * Internal work. Work to disable the clock at some later point.
139 static void mmc_host_clk_gate_work(struct work_struct
*work
)
141 struct mmc_host
*host
= container_of(work
, struct mmc_host
,
144 mmc_host_clk_gate_delayed(host
);
148 * mmc_host_clk_hold - ungate hardware MCI clocks
149 * @host: host to ungate.
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.
155 void mmc_host_clk_hold(struct mmc_host
*host
)
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
));
169 host
->clk_requests
++;
170 spin_unlock_irqrestore(&host
->clk_lock
, flags
);
171 mutex_unlock(&host
->clk_gate_mutex
);
175 * mmc_host_may_gate_card - check if this card may be gated
176 * @card: card to check.
178 static bool mmc_host_may_gate_card(struct mmc_card
*card
)
180 /* If there is no card we may gate it */
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
191 return !(card
->quirks
& MMC_QUIRK_BROKEN_CLK_GATING
);
195 * mmc_host_clk_release - gate off hardware MCI clocks
196 * @host: host to gate.
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.
202 void mmc_host_clk_release(struct mmc_host
*host
)
206 spin_lock_irqsave(&host
->clk_lock
, flags
);
207 host
->clk_requests
--;
208 if (mmc_host_may_gate_card(host
->card
) &&
210 queue_delayed_work(system_nrt_wq
, &host
->clk_gate_work
,
211 msecs_to_jiffies(host
->clkgate_delay
));
212 spin_unlock_irqrestore(&host
->clk_lock
, flags
);
216 * mmc_host_clk_rate - get current clock frequency setting
217 * @host: host to get the clock frequency for.
219 * Returns current clock frequency regardless of gating.
221 unsigned int mmc_host_clk_rate(struct mmc_host
*host
)
226 spin_lock_irqsave(&host
->clk_lock
, flags
);
228 freq
= host
->clk_old
;
230 freq
= host
->ios
.clock
;
231 spin_unlock_irqrestore(&host
->clk_lock
, flags
);
236 * mmc_host_clk_init - set up clock gating code
237 * @host: host with potential clock to control
239 static inline void mmc_host_clk_init(struct mmc_host
*host
)
241 host
->clk_requests
= 0;
242 /* Hold MCI clock for 8 cycles by default */
245 * Default clock gating delay is 200ms.
246 * This value can be tuned by writing into sysfs entry.
248 host
->clkgate_delay
= 200;
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
);
256 * mmc_host_clk_exit - shut down clock gating code
257 * @host: host with potential clock to control
259 static inline void mmc_host_clk_exit(struct mmc_host
*host
)
262 * Wait for any outstanding gate and then make sure we're
263 * ungated before exiting.
265 if (cancel_delayed_work_sync(&host
->clk_gate_work
))
266 mmc_host_clk_gate_delayed(host
);
268 mmc_host_clk_hold(host
);
269 /* There should be only one user now */
270 WARN_ON(host
->clk_requests
> 1);
273 static inline void mmc_host_clk_sysfs_init(struct mmc_host
*host
)
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",
286 static inline void mmc_host_clk_init(struct mmc_host
*host
)
290 static inline void mmc_host_clk_exit(struct mmc_host
*host
)
294 static inline void mmc_host_clk_sysfs_init(struct mmc_host
*host
)
301 * mmc_alloc_host - initialise the per-host structure.
302 * @extra: sizeof private data structure
303 * @dev: pointer to host device model structure
305 * Initialise the per-host structure.
307 struct mmc_host
*mmc_alloc_host(int extra
, struct device
*dev
)
310 struct mmc_host
*host
;
312 if (!idr_pre_get(&mmc_host_idr
, GFP_KERNEL
))
315 host
= kzalloc(sizeof(struct mmc_host
) + extra
, GFP_KERNEL
);
319 spin_lock(&mmc_host_lock
);
320 err
= idr_get_new(&mmc_host_idr
, host
, &host
->index
);
321 spin_unlock(&mmc_host_lock
);
325 dev_set_name(&host
->class_dev
, "mmc%d", host
->index
);
328 host
->class_dev
.parent
= dev
;
329 host
->class_dev
.class = &mmc_host_class
;
330 device_initialize(&host
->class_dev
);
332 mmc_host_clk_init(host
);
334 spin_lock_init(&host
->lock
);
335 init_waitqueue_head(&host
->wq
);
336 INIT_DELAYED_WORK(&host
->detect
, mmc_rescan
);
337 INIT_DELAYED_WORK_DEFERRABLE(&host
->disable
, mmc_host_deeper_disable
);
339 host
->pm_notify
.notifier_call
= mmc_pm_notify
;
343 * By default, hosts do not support SGIO or large requests.
344 * They have to set these according to their abilities.
347 host
->max_seg_size
= PAGE_CACHE_SIZE
;
349 host
->max_req_size
= PAGE_CACHE_SIZE
;
350 host
->max_blk_size
= 512;
351 host
->max_blk_count
= PAGE_CACHE_SIZE
/ 512;
360 EXPORT_SYMBOL(mmc_alloc_host
);
363 * mmc_add_host - initialise host hardware
366 * Register the host with the driver model. The host must be
367 * prepared to start servicing requests before this function
370 int mmc_add_host(struct mmc_host
*host
)
374 WARN_ON((host
->caps
& MMC_CAP_SDIO_IRQ
) &&
375 !host
->ops
->enable_sdio_irq
);
377 err
= device_add(&host
->class_dev
);
381 led_trigger_register_simple(dev_name(&host
->class_dev
), &host
->led
);
383 #ifdef CONFIG_DEBUG_FS
384 mmc_add_host_debugfs(host
);
386 mmc_host_clk_sysfs_init(host
);
388 mmc_start_host(host
);
389 register_pm_notifier(&host
->pm_notify
);
394 EXPORT_SYMBOL(mmc_add_host
);
397 * mmc_remove_host - remove host hardware
400 * Unregister and remove all cards associated with this host,
401 * and power down the MMC bus. No new requests will be issued
402 * after this function has returned.
404 void mmc_remove_host(struct mmc_host
*host
)
406 unregister_pm_notifier(&host
->pm_notify
);
409 #ifdef CONFIG_DEBUG_FS
410 mmc_remove_host_debugfs(host
);
413 device_del(&host
->class_dev
);
415 led_trigger_unregister_simple(host
->led
);
417 mmc_host_clk_exit(host
);
420 EXPORT_SYMBOL(mmc_remove_host
);
423 * mmc_free_host - free the host structure
426 * Free the host once all references to it have been dropped.
428 void mmc_free_host(struct mmc_host
*host
)
430 spin_lock(&mmc_host_lock
);
431 idr_remove(&mmc_host_idr
, host
->index
);
432 spin_unlock(&mmc_host_lock
);
434 put_device(&host
->class_dev
);
437 EXPORT_SYMBOL(mmc_free_host
);