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/leds.h>
20 #include <linux/slab.h>
21 #include <linux/suspend.h>
23 #include <linux/mmc/host.h>
24 #include <linux/mmc/card.h>
29 #define cls_dev_to_mmc_host(d) container_of(d, struct mmc_host, class_dev)
31 static void mmc_host_classdev_release(struct device *dev)
33 struct mmc_host *host = cls_dev_to_mmc_host(dev);
37 static struct class mmc_host_class = {
39 .dev_release = mmc_host_classdev_release,
42 int mmc_register_host_class(void)
44 return class_register(&mmc_host_class);
47 void mmc_unregister_host_class(void)
49 class_unregister(&mmc_host_class);
52 static DEFINE_IDR(mmc_host_idr);
53 static DEFINE_SPINLOCK(mmc_host_lock);
55 #ifdef CONFIG_MMC_CLKGATE
58 * Enabling clock gating will make the core call out to the host
59 * once up and once down when it performs a request or card operation
60 * intermingled in any fashion. The driver will see this through
61 * set_ios() operations with ios.clock field set to 0 to gate
62 * (disable) the block clock, and to the old frequency to enable
65 static void mmc_host_clk_gate_delayed(struct mmc_host *host)
67 unsigned long tick_ns;
68 unsigned long freq = host->ios.clock;
73 pr_err("%s: frequency set to 0 in disable function, "
74 "this means the clock is already disabled.\n",
79 * New requests may have appeared while we were scheduling,
80 * then there is no reason to delay the check before
83 spin_lock_irqsave(&host->clk_lock, flags);
84 users = host->clk_requests;
86 * Delay n bus cycles (at least 8 from MMC spec) before attempting
87 * to disable the MCI block clock. The reference count
88 * may have gone up again after this delay due to
92 spin_unlock_irqrestore(&host->clk_lock, flags);
93 tick_ns = DIV_ROUND_UP(1000000000, freq);
94 ndelay(host->clk_delay * tick_ns);
96 /* New users appeared while waiting for this work */
97 host->clk_pending_gate = false;
98 spin_unlock_irqrestore(&host->clk_lock, flags);
101 spin_lock_irqsave(&host->clk_lock, flags);
102 if (!host->clk_requests) {
103 spin_unlock_irqrestore(&host->clk_lock, flags);
104 /* this will set host->ios.clock to 0 */
105 mmc_gate_clock(host);
106 spin_lock_irqsave(&host->clk_lock, flags);
107 pr_debug("%s: gated MCI clock\n",
110 host->clk_pending_gate = false;
111 spin_unlock_irqrestore(&host->clk_lock, flags);
115 * Internal work. Work to disable the clock at some later point.
117 static void mmc_host_clk_gate_work(struct work_struct *work)
119 struct mmc_host *host = container_of(work, struct mmc_host,
122 mmc_host_clk_gate_delayed(host);
126 * mmc_host_clk_ungate - make sure the host ios.clock is
127 * restored to some non-zero value past this call.
128 * @host: host to ungate.
130 * Increase clock reference count and ungate clock if first user.
132 void mmc_host_clk_ungate(struct mmc_host *host)
136 spin_lock_irqsave(&host->clk_lock, flags);
137 if (host->clk_gated) {
138 spin_unlock_irqrestore(&host->clk_lock, flags);
139 mmc_ungate_clock(host);
140 spin_lock_irqsave(&host->clk_lock, flags);
141 pr_debug("%s: ungated MCI clock\n",
144 host->clk_requests++;
145 spin_unlock_irqrestore(&host->clk_lock, flags);
149 * mmc_host_may_gate_card - check if this card may be gated
150 * @card: card to check.
152 static bool mmc_host_may_gate_card(struct mmc_card *card)
154 /* If there is no card we may gate it */
158 * Don't gate SDIO cards! These need to be clocked at all times
159 * since they may be independent systems generating interrupts
160 * and other events. The clock requests counter from the core will
161 * go down to zero since the core does not need it, but we will not
162 * gate the clock, because there is somebody out there that may still
165 if (mmc_card_sdio(card))
172 * mmc_host_clk_gate - call the host driver with ios.clock
173 * set to zero as often as possible so as to make it
174 * possible to gate off hardware MCI clocks.
175 * @host: host to gate.
177 * Decrease clock reference count and schedule disablement of clock.
179 void mmc_host_clk_gate(struct mmc_host *host)
183 spin_lock_irqsave(&host->clk_lock, flags);
184 host->clk_requests--;
185 if (mmc_host_may_gate_card(host->card) &&
186 !host->clk_requests) {
187 host->clk_pending_gate = true;
188 schedule_work(&host->clk_disable_work);
190 spin_unlock_irqrestore(&host->clk_lock, flags);
194 * mmc_host_clk_rate - get current clock frequency setting no matter
195 * whether it's gated or not.
196 * @host: host to get the clock frequency for.
198 unsigned int mmc_host_clk_rate(struct mmc_host *host)
203 spin_lock_irqsave(&host->clk_lock, flags);
205 freq = host->clk_old;
207 freq = host->ios.clock;
208 spin_unlock_irqrestore(&host->clk_lock, flags);
213 * mmc_host_clk_init - set up clock gating code
214 * @host: host with potential clock to control
216 static inline void mmc_host_clk_init(struct mmc_host *host)
218 host->clk_requests = 0;
219 host->clk_delay = 8; /* hold MCI clock in 8 cycles by default */
220 host->clk_gated = false;
221 host->clk_pending_gate = false;
222 INIT_WORK(&host->clk_disable_work, mmc_host_clk_gate_work);
223 spin_lock_init(&host->clk_lock);
227 * mmc_host_clk_exit - shut down clock gating code
228 * @host: host with potential clock to control
230 static inline void mmc_host_clk_exit(struct mmc_host *host)
233 * Wait for any outstanding gate and then make sure we're
234 * ungated before exiting.
236 if (cancel_work_sync(&host->clk_disable_work))
237 mmc_host_clk_gate_delayed(host);
239 mmc_host_clk_ungate(host);
240 BUG_ON(host->clk_requests > 0);
245 static inline void mmc_host_clk_init(struct mmc_host *host)
249 static inline void mmc_host_clk_exit(struct mmc_host *host)
256 * mmc_alloc_host - initialise the per-host structure.
257 * @extra: sizeof private data structure
258 * @dev: pointer to host device model structure
260 * Initialise the per-host structure.
262 struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
265 struct mmc_host *host;
267 if (!idr_pre_get(&mmc_host_idr, GFP_KERNEL))
270 host = kzalloc(sizeof(struct mmc_host) + extra, GFP_KERNEL);
274 spin_lock(&mmc_host_lock);
275 err = idr_get_new(&mmc_host_idr, host, &host->index);
276 spin_unlock(&mmc_host_lock);
280 dev_set_name(&host->class_dev, "mmc%d", host->index);
283 host->class_dev.parent = dev;
284 host->class_dev.class = &mmc_host_class;
285 device_initialize(&host->class_dev);
287 mmc_host_clk_init(host);
289 spin_lock_init(&host->lock);
290 init_waitqueue_head(&host->wq);
291 INIT_DELAYED_WORK(&host->detect, mmc_rescan);
292 INIT_DELAYED_WORK_DEFERRABLE(&host->disable, mmc_host_deeper_disable);
294 host->pm_notify.notifier_call = mmc_pm_notify;
298 * By default, hosts do not support SGIO or large requests.
299 * They have to set these according to their abilities.
301 host->max_hw_segs = 1;
302 host->max_phys_segs = 1;
303 host->max_seg_size = PAGE_CACHE_SIZE;
305 host->max_req_size = PAGE_CACHE_SIZE;
306 host->max_blk_size = 512;
307 host->max_blk_count = PAGE_CACHE_SIZE / 512;
316 EXPORT_SYMBOL(mmc_alloc_host);
319 * mmc_add_host - initialise host hardware
322 * Register the host with the driver model. The host must be
323 * prepared to start servicing requests before this function
326 int mmc_add_host(struct mmc_host *host)
330 WARN_ON((host->caps & MMC_CAP_SDIO_IRQ) &&
331 !host->ops->enable_sdio_irq);
333 led_trigger_register_simple(dev_name(&host->class_dev), &host->led);
335 err = device_add(&host->class_dev);
339 #ifdef CONFIG_DEBUG_FS
340 mmc_add_host_debugfs(host);
343 mmc_start_host(host);
344 register_pm_notifier(&host->pm_notify);
349 EXPORT_SYMBOL(mmc_add_host);
352 * mmc_remove_host - remove host hardware
355 * Unregister and remove all cards associated with this host,
356 * and power down the MMC bus. No new requests will be issued
357 * after this function has returned.
359 void mmc_remove_host(struct mmc_host *host)
361 unregister_pm_notifier(&host->pm_notify);
364 #ifdef CONFIG_DEBUG_FS
365 mmc_remove_host_debugfs(host);
368 device_del(&host->class_dev);
370 led_trigger_unregister_simple(host->led);
372 mmc_host_clk_exit(host);
375 EXPORT_SYMBOL(mmc_remove_host);
378 * mmc_free_host - free the host structure
381 * Free the host once all references to it have been dropped.
383 void mmc_free_host(struct mmc_host *host)
385 spin_lock(&mmc_host_lock);
386 idr_remove(&mmc_host_idr, host->index);
387 spin_unlock(&mmc_host_lock);
389 put_device(&host->class_dev);
392 EXPORT_SYMBOL(mmc_free_host);