mmc: queue: let host controllers specify maximum discard timeout
[linux-2.6.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/slab.h>
13 #include <linux/module.h>
14 #include <linux/blkdev.h>
15 #include <linux/freezer.h>
16 #include <linux/kthread.h>
17 #include <linux/scatterlist.h>
18
19 #include <linux/mmc/card.h>
20 #include <linux/mmc/host.h>
21 #include "queue.h"
22
23 #define MMC_QUEUE_BOUNCESZ      65536
24
25 #define MMC_QUEUE_SUSPENDED     (1 << 0)
26
27 /*
28  * Prepare a MMC request. This just filters out odd stuff.
29  */
30 static int mmc_prep_request(struct request_queue *q, struct request *req)
31 {
32         /*
33          * We only like normal block requests and discards.
34          */
35         if (req->cmd_type != REQ_TYPE_FS && !(req->cmd_flags & REQ_DISCARD)) {
36                 blk_dump_rq_flags(req, "MMC bad request");
37                 return BLKPREP_KILL;
38         }
39
40         req->cmd_flags |= REQ_DONTPREP;
41
42         return BLKPREP_OK;
43 }
44
45 static int mmc_queue_thread(void *d)
46 {
47         struct mmc_queue *mq = d;
48         struct request_queue *q = mq->queue;
49
50         current->flags |= PF_MEMALLOC;
51
52         down(&mq->thread_sem);
53         do {
54                 struct request *req = NULL;
55
56                 spin_lock_irq(q->queue_lock);
57                 set_current_state(TASK_INTERRUPTIBLE);
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 static void mmc_queue_setup_discard(struct request_queue *q,
105                                     struct mmc_card *card)
106 {
107         unsigned max_discard;
108
109         max_discard = mmc_calc_max_discard(card);
110         if (!max_discard)
111                 return;
112
113         queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
114         q->limits.max_discard_sectors = max_discard;
115         if (card->erased_byte == 0)
116                 q->limits.discard_zeroes_data = 1;
117         q->limits.discard_granularity = card->pref_erase << 9;
118         /* granularity must not be greater than max. discard */
119         if (card->pref_erase > max_discard)
120                 q->limits.discard_granularity = 0;
121         if (mmc_can_secure_erase_trim(card))
122                 queue_flag_set_unlocked(QUEUE_FLAG_SECDISCARD, q);
123 }
124
125 /**
126  * mmc_init_queue - initialise a queue structure.
127  * @mq: mmc queue
128  * @card: mmc card to attach this queue
129  * @lock: queue lock
130  * @subname: partition subname
131  *
132  * Initialise a MMC card request queue.
133  */
134 int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card,
135                    spinlock_t *lock, const char *subname)
136 {
137         struct mmc_host *host = card->host;
138         u64 limit = BLK_BOUNCE_HIGH;
139         int ret;
140
141         if (mmc_dev(host)->dma_mask && *mmc_dev(host)->dma_mask)
142                 limit = *mmc_dev(host)->dma_mask;
143
144         mq->card = card;
145         mq->queue = blk_init_queue(mmc_request, lock);
146         if (!mq->queue)
147                 return -ENOMEM;
148
149         mq->queue->queuedata = mq;
150         mq->req = NULL;
151
152         blk_queue_prep_rq(mq->queue, mmc_prep_request);
153         queue_flag_set_unlocked(QUEUE_FLAG_NONROT, mq->queue);
154         if (mmc_can_erase(card))
155                 mmc_queue_setup_discard(mq->queue, card);
156
157 #ifdef CONFIG_MMC_BLOCK_BOUNCE
158         if (host->max_segs == 1) {
159                 unsigned int bouncesz;
160
161                 bouncesz = MMC_QUEUE_BOUNCESZ;
162
163                 if (bouncesz > host->max_req_size)
164                         bouncesz = host->max_req_size;
165                 if (bouncesz > host->max_seg_size)
166                         bouncesz = host->max_seg_size;
167                 if (bouncesz > (host->max_blk_count * 512))
168                         bouncesz = host->max_blk_count * 512;
169
170                 if (bouncesz > 512) {
171                         mq->bounce_buf = kmalloc(bouncesz, GFP_KERNEL);
172                         if (!mq->bounce_buf) {
173                                 printk(KERN_WARNING "%s: unable to "
174                                         "allocate bounce buffer\n",
175                                         mmc_card_name(card));
176                         }
177                 }
178
179                 if (mq->bounce_buf) {
180                         blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_ANY);
181                         blk_queue_max_hw_sectors(mq->queue, bouncesz / 512);
182                         blk_queue_max_segments(mq->queue, bouncesz / 512);
183                         blk_queue_max_segment_size(mq->queue, bouncesz);
184
185                         mq->sg = kmalloc(sizeof(struct scatterlist),
186                                 GFP_KERNEL);
187                         if (!mq->sg) {
188                                 ret = -ENOMEM;
189                                 goto cleanup_queue;
190                         }
191                         sg_init_table(mq->sg, 1);
192
193                         mq->bounce_sg = kmalloc(sizeof(struct scatterlist) *
194                                 bouncesz / 512, GFP_KERNEL);
195                         if (!mq->bounce_sg) {
196                                 ret = -ENOMEM;
197                                 goto cleanup_queue;
198                         }
199                         sg_init_table(mq->bounce_sg, bouncesz / 512);
200                 }
201         }
202 #endif
203
204         if (!mq->bounce_buf) {
205                 blk_queue_bounce_limit(mq->queue, limit);
206                 blk_queue_max_hw_sectors(mq->queue,
207                         min(host->max_blk_count, host->max_req_size / 512));
208                 blk_queue_max_segments(mq->queue, host->max_segs);
209                 blk_queue_max_segment_size(mq->queue, host->max_seg_size);
210
211                 mq->sg = kmalloc(sizeof(struct scatterlist) *
212                         host->max_segs, GFP_KERNEL);
213                 if (!mq->sg) {
214                         ret = -ENOMEM;
215                         goto cleanup_queue;
216                 }
217                 sg_init_table(mq->sg, host->max_segs);
218         }
219
220         sema_init(&mq->thread_sem, 1);
221
222         mq->thread = kthread_run(mmc_queue_thread, mq, "mmcqd/%d%s",
223                 host->index, subname ? subname : "");
224
225         if (IS_ERR(mq->thread)) {
226                 ret = PTR_ERR(mq->thread);
227                 goto free_bounce_sg;
228         }
229
230         return 0;
231  free_bounce_sg:
232         if (mq->bounce_sg)
233                 kfree(mq->bounce_sg);
234         mq->bounce_sg = NULL;
235  cleanup_queue:
236         if (mq->sg)
237                 kfree(mq->sg);
238         mq->sg = NULL;
239         if (mq->bounce_buf)
240                 kfree(mq->bounce_buf);
241         mq->bounce_buf = NULL;
242         blk_cleanup_queue(mq->queue);
243         return ret;
244 }
245
246 void mmc_cleanup_queue(struct mmc_queue *mq)
247 {
248         struct request_queue *q = mq->queue;
249         unsigned long flags;
250
251         /* Make sure the queue isn't suspended, as that will deadlock */
252         mmc_queue_resume(mq);
253
254         /* Then terminate our worker thread */
255         kthread_stop(mq->thread);
256
257         /* Empty the queue */
258         spin_lock_irqsave(q->queue_lock, flags);
259         q->queuedata = NULL;
260         blk_start_queue(q);
261         spin_unlock_irqrestore(q->queue_lock, flags);
262
263         if (mq->bounce_sg)
264                 kfree(mq->bounce_sg);
265         mq->bounce_sg = NULL;
266
267         kfree(mq->sg);
268         mq->sg = NULL;
269
270         if (mq->bounce_buf)
271                 kfree(mq->bounce_buf);
272         mq->bounce_buf = NULL;
273
274         mq->card = NULL;
275 }
276 EXPORT_SYMBOL(mmc_cleanup_queue);
277
278 /**
279  * mmc_queue_suspend - suspend a MMC request queue
280  * @mq: MMC queue to suspend
281  *
282  * Stop the block request queue, and wait for our thread to
283  * complete any outstanding requests.  This ensures that we
284  * won't suspend while a request is being processed.
285  */
286 void mmc_queue_suspend(struct mmc_queue *mq)
287 {
288         struct request_queue *q = mq->queue;
289         unsigned long flags;
290
291         if (!(mq->flags & MMC_QUEUE_SUSPENDED)) {
292                 mq->flags |= MMC_QUEUE_SUSPENDED;
293
294                 spin_lock_irqsave(q->queue_lock, flags);
295                 blk_stop_queue(q);
296                 spin_unlock_irqrestore(q->queue_lock, flags);
297
298                 down(&mq->thread_sem);
299         }
300 }
301
302 /**
303  * mmc_queue_resume - resume a previously suspended MMC request queue
304  * @mq: MMC queue to resume
305  */
306 void mmc_queue_resume(struct mmc_queue *mq)
307 {
308         struct request_queue *q = mq->queue;
309         unsigned long flags;
310
311         if (mq->flags & MMC_QUEUE_SUSPENDED) {
312                 mq->flags &= ~MMC_QUEUE_SUSPENDED;
313
314                 up(&mq->thread_sem);
315
316                 spin_lock_irqsave(q->queue_lock, flags);
317                 blk_start_queue(q);
318                 spin_unlock_irqrestore(q->queue_lock, flags);
319         }
320 }
321
322 /*
323  * Prepare the sg list(s) to be handed of to the host driver
324  */
325 unsigned int mmc_queue_map_sg(struct mmc_queue *mq)
326 {
327         unsigned int sg_len;
328         size_t buflen;
329         struct scatterlist *sg;
330         int i;
331
332         if (!mq->bounce_buf)
333                 return blk_rq_map_sg(mq->queue, mq->req, mq->sg);
334
335         BUG_ON(!mq->bounce_sg);
336
337         sg_len = blk_rq_map_sg(mq->queue, mq->req, mq->bounce_sg);
338
339         mq->bounce_sg_len = sg_len;
340
341         buflen = 0;
342         for_each_sg(mq->bounce_sg, sg, sg_len, i)
343                 buflen += sg->length;
344
345         sg_init_one(mq->sg, mq->bounce_buf, buflen);
346
347         return 1;
348 }
349
350 /*
351  * If writing, bounce the data to the buffer before the request
352  * is sent to the host driver
353  */
354 void mmc_queue_bounce_pre(struct mmc_queue *mq)
355 {
356         if (!mq->bounce_buf)
357                 return;
358
359         if (rq_data_dir(mq->req) != WRITE)
360                 return;
361
362         sg_copy_to_buffer(mq->bounce_sg, mq->bounce_sg_len,
363                 mq->bounce_buf, mq->sg[0].length);
364 }
365
366 /*
367  * If reading, bounce the data from the buffer after the request
368  * has been handled by the host driver
369  */
370 void mmc_queue_bounce_post(struct mmc_queue *mq)
371 {
372         if (!mq->bounce_buf)
373                 return;
374
375         if (rq_data_dir(mq->req) != READ)
376                 return;
377
378         sg_copy_from_buffer(mq->bounce_sg, mq->bounce_sg_len,
379                 mq->bounce_buf, mq->sg[0].length);
380 }
381