block: Consolidate phys_segment and hw_segment limits
[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_segments(mq->queue, bouncesz / 512);
159                         blk_queue_max_segment_size(mq->queue, bouncesz);
160
161                         mq->sg = kmalloc(sizeof(struct scatterlist),
162                                 GFP_KERNEL);
163                         if (!mq->sg) {
164                                 ret = -ENOMEM;
165                                 goto cleanup_queue;
166                         }
167                         sg_init_table(mq->sg, 1);
168
169                         mq->bounce_sg = kmalloc(sizeof(struct scatterlist) *
170                                 bouncesz / 512, GFP_KERNEL);
171                         if (!mq->bounce_sg) {
172                                 ret = -ENOMEM;
173                                 goto cleanup_queue;
174                         }
175                         sg_init_table(mq->bounce_sg, bouncesz / 512);
176                 }
177         }
178 #endif
179
180         if (!mq->bounce_buf) {
181                 blk_queue_bounce_limit(mq->queue, limit);
182                 blk_queue_max_hw_sectors(mq->queue,
183                         min(host->max_blk_count, host->max_req_size / 512));
184                 blk_queue_max_segments(mq->queue, host->max_hw_segs);
185                 blk_queue_max_segment_size(mq->queue, host->max_seg_size);
186
187                 mq->sg = kmalloc(sizeof(struct scatterlist) *
188                         host->max_phys_segs, GFP_KERNEL);
189                 if (!mq->sg) {
190                         ret = -ENOMEM;
191                         goto cleanup_queue;
192                 }
193                 sg_init_table(mq->sg, host->max_phys_segs);
194         }
195
196         init_MUTEX(&mq->thread_sem);
197
198         mq->thread = kthread_run(mmc_queue_thread, mq, "mmcqd");
199         if (IS_ERR(mq->thread)) {
200                 ret = PTR_ERR(mq->thread);
201                 goto free_bounce_sg;
202         }
203
204         return 0;
205  free_bounce_sg:
206         if (mq->bounce_sg)
207                 kfree(mq->bounce_sg);
208         mq->bounce_sg = NULL;
209  cleanup_queue:
210         if (mq->sg)
211                 kfree(mq->sg);
212         mq->sg = NULL;
213         if (mq->bounce_buf)
214                 kfree(mq->bounce_buf);
215         mq->bounce_buf = NULL;
216         blk_cleanup_queue(mq->queue);
217         return ret;
218 }
219
220 void mmc_cleanup_queue(struct mmc_queue *mq)
221 {
222         struct request_queue *q = mq->queue;
223         unsigned long flags;
224
225         /* Make sure the queue isn't suspended, as that will deadlock */
226         mmc_queue_resume(mq);
227
228         /* Then terminate our worker thread */
229         kthread_stop(mq->thread);
230
231         /* Empty the queue */
232         spin_lock_irqsave(q->queue_lock, flags);
233         q->queuedata = NULL;
234         blk_start_queue(q);
235         spin_unlock_irqrestore(q->queue_lock, flags);
236
237         if (mq->bounce_sg)
238                 kfree(mq->bounce_sg);
239         mq->bounce_sg = NULL;
240
241         kfree(mq->sg);
242         mq->sg = NULL;
243
244         if (mq->bounce_buf)
245                 kfree(mq->bounce_buf);
246         mq->bounce_buf = NULL;
247
248         mq->card = NULL;
249 }
250 EXPORT_SYMBOL(mmc_cleanup_queue);
251
252 /**
253  * mmc_queue_suspend - suspend a MMC request queue
254  * @mq: MMC queue to suspend
255  *
256  * Stop the block request queue, and wait for our thread to
257  * complete any outstanding requests.  This ensures that we
258  * won't suspend while a request is being processed.
259  */
260 void mmc_queue_suspend(struct mmc_queue *mq)
261 {
262         struct request_queue *q = mq->queue;
263         unsigned long flags;
264
265         if (!(mq->flags & MMC_QUEUE_SUSPENDED)) {
266                 mq->flags |= MMC_QUEUE_SUSPENDED;
267
268                 spin_lock_irqsave(q->queue_lock, flags);
269                 blk_stop_queue(q);
270                 spin_unlock_irqrestore(q->queue_lock, flags);
271
272                 down(&mq->thread_sem);
273         }
274 }
275
276 /**
277  * mmc_queue_resume - resume a previously suspended MMC request queue
278  * @mq: MMC queue to resume
279  */
280 void mmc_queue_resume(struct mmc_queue *mq)
281 {
282         struct request_queue *q = mq->queue;
283         unsigned long flags;
284
285         if (mq->flags & MMC_QUEUE_SUSPENDED) {
286                 mq->flags &= ~MMC_QUEUE_SUSPENDED;
287
288                 up(&mq->thread_sem);
289
290                 spin_lock_irqsave(q->queue_lock, flags);
291                 blk_start_queue(q);
292                 spin_unlock_irqrestore(q->queue_lock, flags);
293         }
294 }
295
296 /*
297  * Prepare the sg list(s) to be handed of to the host driver
298  */
299 unsigned int mmc_queue_map_sg(struct mmc_queue *mq)
300 {
301         unsigned int sg_len;
302         size_t buflen;
303         struct scatterlist *sg;
304         int i;
305
306         if (!mq->bounce_buf)
307                 return blk_rq_map_sg(mq->queue, mq->req, mq->sg);
308
309         BUG_ON(!mq->bounce_sg);
310
311         sg_len = blk_rq_map_sg(mq->queue, mq->req, mq->bounce_sg);
312
313         mq->bounce_sg_len = sg_len;
314
315         buflen = 0;
316         for_each_sg(mq->bounce_sg, sg, sg_len, i)
317                 buflen += sg->length;
318
319         sg_init_one(mq->sg, mq->bounce_buf, buflen);
320
321         return 1;
322 }
323
324 /*
325  * If writing, bounce the data to the buffer before the request
326  * is sent to the host driver
327  */
328 void mmc_queue_bounce_pre(struct mmc_queue *mq)
329 {
330         unsigned long flags;
331
332         if (!mq->bounce_buf)
333                 return;
334
335         if (rq_data_dir(mq->req) != WRITE)
336                 return;
337
338         local_irq_save(flags);
339         sg_copy_to_buffer(mq->bounce_sg, mq->bounce_sg_len,
340                 mq->bounce_buf, mq->sg[0].length);
341         local_irq_restore(flags);
342 }
343
344 /*
345  * If reading, bounce the data from the buffer after the request
346  * has been handled by the host driver
347  */
348 void mmc_queue_bounce_post(struct mmc_queue *mq)
349 {
350         unsigned long flags;
351
352         if (!mq->bounce_buf)
353                 return;
354
355         if (rq_data_dir(mq->req) != READ)
356                 return;
357
358         local_irq_save(flags);
359         sg_copy_from_buffer(mq->bounce_sg, mq->bounce_sg_len,
360                 mq->bounce_buf, mq->sg[0].length);
361         local_irq_restore(flags);
362 }
363