09b633d5657b706aab8bc81e3cdc23c6e9015cac
[linux-3.10.git] / drivers / mmc / card / queue.c
1 /*
2  *  linux/drivers/mmc/card/queue.c
3  *
4  *  Copyright (C) 2003 Russell King, All Rights Reserved.
5  *  Copyright 2006-2007 Pierre Ossman
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2 as
9  * published by the Free Software Foundation.
10  *
11  */
12 #include <linux/module.h>
13 #include <linux/blkdev.h>
14 #include <linux/freezer.h>
15 #include <linux/kthread.h>
16 #include <linux/scatterlist.h>
17
18 #include <linux/mmc/card.h>
19 #include <linux/mmc/host.h>
20 #include "queue.h"
21
22 #define MMC_QUEUE_BOUNCESZ      65536
23
24 #define MMC_QUEUE_SUSPENDED     (1 << 0)
25
26 /*
27  * Prepare a MMC request. This just filters out odd stuff.
28  */
29 static int mmc_prep_request(struct request_queue *q, struct request *req)
30 {
31         /*
32          * We only like normal block requests.
33          */
34         if (!blk_fs_request(req)) {
35                 blk_dump_rq_flags(req, "MMC bad request");
36                 return BLKPREP_KILL;
37         }
38
39         req->cmd_flags |= REQ_DONTPREP;
40
41         return BLKPREP_OK;
42 }
43
44 static int mmc_queue_thread(void *d)
45 {
46         struct mmc_queue *mq = d;
47         struct request_queue *q = mq->queue;
48
49         current->flags |= PF_MEMALLOC;
50
51         down(&mq->thread_sem);
52         do {
53                 struct request *req = NULL;
54
55                 spin_lock_irq(q->queue_lock);
56                 set_current_state(TASK_INTERRUPTIBLE);
57                 if (!blk_queue_plugged(q))
58                         req = blk_fetch_request(q);
59                 mq->req = req;
60                 spin_unlock_irq(q->queue_lock);
61
62                 if (!req) {
63                         if (kthread_should_stop()) {
64                                 set_current_state(TASK_RUNNING);
65                                 break;
66                         }
67                         up(&mq->thread_sem);
68                         schedule();
69                         down(&mq->thread_sem);
70                         continue;
71                 }
72                 set_current_state(TASK_RUNNING);
73
74                 mq->issue_fn(mq, req);
75         } while (1);
76         up(&mq->thread_sem);
77
78         return 0;
79 }
80
81 /*
82  * Generic MMC request handler.  This is called for any queue on a
83  * particular host.  When the host is not busy, we look for a request
84  * on any queue on this host, and attempt to issue it.  This may
85  * not be the queue we were asked to process.
86  */
87 static void mmc_request(struct request_queue *q)
88 {
89         struct mmc_queue *mq = q->queuedata;
90         struct request *req;
91
92         if (!mq) {
93                 while ((req = blk_fetch_request(q)) != NULL) {
94                         req->cmd_flags |= REQ_QUIET;
95                         __blk_end_request_all(req, -EIO);
96                 }
97                 return;
98         }
99
100         if (!mq->req)
101                 wake_up_process(mq->thread);
102 }
103
104 /**
105  * mmc_init_queue - initialise a queue structure.
106  * @mq: mmc queue
107  * @card: mmc card to attach this queue
108  * @lock: queue lock
109  *
110  * Initialise a MMC card request queue.
111  */
112 int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card, spinlock_t *lock)
113 {
114         struct mmc_host *host = card->host;
115         u64 limit = BLK_BOUNCE_HIGH;
116         int ret;
117
118         if (mmc_dev(host)->dma_mask && *mmc_dev(host)->dma_mask)
119                 limit = *mmc_dev(host)->dma_mask;
120
121         mq->card = card;
122         mq->queue = blk_init_queue(mmc_request, lock);
123         if (!mq->queue)
124                 return -ENOMEM;
125
126         mq->queue->queuedata = mq;
127         mq->req = NULL;
128
129         blk_queue_prep_rq(mq->queue, mmc_prep_request);
130         blk_queue_ordered(mq->queue, QUEUE_ORDERED_DRAIN, NULL);
131         queue_flag_set_unlocked(QUEUE_FLAG_NONROT, mq->queue);
132
133 #ifdef CONFIG_MMC_BLOCK_BOUNCE
134         if (host->max_hw_segs == 1) {
135                 unsigned int bouncesz;
136
137                 bouncesz = MMC_QUEUE_BOUNCESZ;
138
139                 if (bouncesz > host->max_req_size)
140                         bouncesz = host->max_req_size;
141                 if (bouncesz > host->max_seg_size)
142                         bouncesz = host->max_seg_size;
143                 if (bouncesz > (host->max_blk_count * 512))
144                         bouncesz = host->max_blk_count * 512;
145
146                 if (bouncesz > 512) {
147                         mq->bounce_buf = kmalloc(bouncesz, GFP_KERNEL);
148                         if (!mq->bounce_buf) {
149                                 printk(KERN_WARNING "%s: unable to "
150                                         "allocate bounce buffer\n",
151                                         mmc_card_name(card));
152                         }
153                 }
154
155                 if (mq->bounce_buf) {
156                         blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_ANY);
157                         blk_queue_max_hw_sectors(mq->queue, bouncesz / 512);
158                         blk_queue_max_phys_segments(mq->queue, bouncesz / 512);
159                         blk_queue_max_hw_segments(mq->queue, bouncesz / 512);
160                         blk_queue_max_segment_size(mq->queue, bouncesz);
161
162                         mq->sg = kmalloc(sizeof(struct scatterlist),
163                                 GFP_KERNEL);
164                         if (!mq->sg) {
165                                 ret = -ENOMEM;
166                                 goto cleanup_queue;
167                         }
168                         sg_init_table(mq->sg, 1);
169
170                         mq->bounce_sg = kmalloc(sizeof(struct scatterlist) *
171                                 bouncesz / 512, GFP_KERNEL);
172                         if (!mq->bounce_sg) {
173                                 ret = -ENOMEM;
174                                 goto cleanup_queue;
175                         }
176                         sg_init_table(mq->bounce_sg, bouncesz / 512);
177                 }
178         }
179 #endif
180
181         if (!mq->bounce_buf) {
182                 blk_queue_bounce_limit(mq->queue, limit);
183                 blk_queue_max_hw_sectors(mq->queue,
184                         min(host->max_blk_count, host->max_req_size / 512));
185                 blk_queue_max_phys_segments(mq->queue, host->max_phys_segs);
186                 blk_queue_max_hw_segments(mq->queue, host->max_hw_segs);
187                 blk_queue_max_segment_size(mq->queue, host->max_seg_size);
188
189                 mq->sg = kmalloc(sizeof(struct scatterlist) *
190                         host->max_phys_segs, GFP_KERNEL);
191                 if (!mq->sg) {
192                         ret = -ENOMEM;
193                         goto cleanup_queue;
194                 }
195                 sg_init_table(mq->sg, host->max_phys_segs);
196         }
197
198         init_MUTEX(&mq->thread_sem);
199
200         mq->thread = kthread_run(mmc_queue_thread, mq, "mmcqd");
201         if (IS_ERR(mq->thread)) {
202                 ret = PTR_ERR(mq->thread);
203                 goto free_bounce_sg;
204         }
205
206         return 0;
207  free_bounce_sg:
208         if (mq->bounce_sg)
209                 kfree(mq->bounce_sg);
210         mq->bounce_sg = NULL;
211  cleanup_queue:
212         if (mq->sg)
213                 kfree(mq->sg);
214         mq->sg = NULL;
215         if (mq->bounce_buf)
216                 kfree(mq->bounce_buf);
217         mq->bounce_buf = NULL;
218         blk_cleanup_queue(mq->queue);
219         return ret;
220 }
221
222 void mmc_cleanup_queue(struct mmc_queue *mq)
223 {
224         struct request_queue *q = mq->queue;
225         unsigned long flags;
226
227         /* Make sure the queue isn't suspended, as that will deadlock */
228         mmc_queue_resume(mq);
229
230         /* Then terminate our worker thread */
231         kthread_stop(mq->thread);
232
233         /* Empty the queue */
234         spin_lock_irqsave(q->queue_lock, flags);
235         q->queuedata = NULL;
236         blk_start_queue(q);
237         spin_unlock_irqrestore(q->queue_lock, flags);
238
239         if (mq->bounce_sg)
240                 kfree(mq->bounce_sg);
241         mq->bounce_sg = NULL;
242
243         kfree(mq->sg);
244         mq->sg = NULL;
245
246         if (mq->bounce_buf)
247                 kfree(mq->bounce_buf);
248         mq->bounce_buf = NULL;
249
250         mq->card = NULL;
251 }
252 EXPORT_SYMBOL(mmc_cleanup_queue);
253
254 /**
255  * mmc_queue_suspend - suspend a MMC request queue
256  * @mq: MMC queue to suspend
257  *
258  * Stop the block request queue, and wait for our thread to
259  * complete any outstanding requests.  This ensures that we
260  * won't suspend while a request is being processed.
261  */
262 void mmc_queue_suspend(struct mmc_queue *mq)
263 {
264         struct request_queue *q = mq->queue;
265         unsigned long flags;
266
267         if (!(mq->flags & MMC_QUEUE_SUSPENDED)) {
268                 mq->flags |= MMC_QUEUE_SUSPENDED;
269
270                 spin_lock_irqsave(q->queue_lock, flags);
271                 blk_stop_queue(q);
272                 spin_unlock_irqrestore(q->queue_lock, flags);
273
274                 down(&mq->thread_sem);
275         }
276 }
277
278 /**
279  * mmc_queue_resume - resume a previously suspended MMC request queue
280  * @mq: MMC queue to resume
281  */
282 void mmc_queue_resume(struct mmc_queue *mq)
283 {
284         struct request_queue *q = mq->queue;
285         unsigned long flags;
286
287         if (mq->flags & MMC_QUEUE_SUSPENDED) {
288                 mq->flags &= ~MMC_QUEUE_SUSPENDED;
289
290                 up(&mq->thread_sem);
291
292                 spin_lock_irqsave(q->queue_lock, flags);
293                 blk_start_queue(q);
294                 spin_unlock_irqrestore(q->queue_lock, flags);
295         }
296 }
297
298 /*
299  * Prepare the sg list(s) to be handed of to the host driver
300  */
301 unsigned int mmc_queue_map_sg(struct mmc_queue *mq)
302 {
303         unsigned int sg_len;
304         size_t buflen;
305         struct scatterlist *sg;
306         int i;
307
308         if (!mq->bounce_buf)
309                 return blk_rq_map_sg(mq->queue, mq->req, mq->sg);
310
311         BUG_ON(!mq->bounce_sg);
312
313         sg_len = blk_rq_map_sg(mq->queue, mq->req, mq->bounce_sg);
314
315         mq->bounce_sg_len = sg_len;
316
317         buflen = 0;
318         for_each_sg(mq->bounce_sg, sg, sg_len, i)
319                 buflen += sg->length;
320
321         sg_init_one(mq->sg, mq->bounce_buf, buflen);
322
323         return 1;
324 }
325
326 /*
327  * If writing, bounce the data to the buffer before the request
328  * is sent to the host driver
329  */
330 void mmc_queue_bounce_pre(struct mmc_queue *mq)
331 {
332         unsigned long flags;
333
334         if (!mq->bounce_buf)
335                 return;
336
337         if (rq_data_dir(mq->req) != WRITE)
338                 return;
339
340         local_irq_save(flags);
341         sg_copy_to_buffer(mq->bounce_sg, mq->bounce_sg_len,
342                 mq->bounce_buf, mq->sg[0].length);
343         local_irq_restore(flags);
344 }
345
346 /*
347  * If reading, bounce the data from the buffer after the request
348  * has been handled by the host driver
349  */
350 void mmc_queue_bounce_post(struct mmc_queue *mq)
351 {
352         unsigned long flags;
353
354         if (!mq->bounce_buf)
355                 return;
356
357         if (rq_data_dir(mq->req) != READ)
358                 return;
359
360         local_irq_save(flags);
361         sg_copy_from_buffer(mq->bounce_sg, mq->bounce_sg_len,
362                 mq->bounce_buf, mq->sg[0].length);
363         local_irq_restore(flags);
364 }
365