Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6
[linux-2.6] / 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 = elv_next_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         int ret;
92
93         if (!mq) {
94                 printk(KERN_ERR "MMC: killing requests for dead queue\n");
95                 while ((req = elv_next_request(q)) != NULL) {
96                         do {
97                                 ret = __blk_end_request(req, -EIO,
98                                                         blk_rq_cur_bytes(req));
99                         } while (ret);
100                 }
101                 return;
102         }
103
104         if (!mq->req)
105                 wake_up_process(mq->thread);
106 }
107
108 /**
109  * mmc_init_queue - initialise a queue structure.
110  * @mq: mmc queue
111  * @card: mmc card to attach this queue
112  * @lock: queue lock
113  *
114  * Initialise a MMC card request queue.
115  */
116 int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card, spinlock_t *lock)
117 {
118         struct mmc_host *host = card->host;
119         u64 limit = BLK_BOUNCE_HIGH;
120         int ret;
121
122         if (mmc_dev(host)->dma_mask && *mmc_dev(host)->dma_mask)
123                 limit = *mmc_dev(host)->dma_mask;
124
125         mq->card = card;
126         mq->queue = blk_init_queue(mmc_request, lock);
127         if (!mq->queue)
128                 return -ENOMEM;
129
130         mq->queue->queuedata = mq;
131         mq->req = NULL;
132
133         blk_queue_prep_rq(mq->queue, mmc_prep_request);
134         blk_queue_ordered(mq->queue, QUEUE_ORDERED_DRAIN, NULL);
135
136 #ifdef CONFIG_MMC_BLOCK_BOUNCE
137         if (host->max_hw_segs == 1) {
138                 unsigned int bouncesz;
139
140                 bouncesz = MMC_QUEUE_BOUNCESZ;
141
142                 if (bouncesz > host->max_req_size)
143                         bouncesz = host->max_req_size;
144                 if (bouncesz > host->max_seg_size)
145                         bouncesz = host->max_seg_size;
146                 if (bouncesz > (host->max_blk_count * 512))
147                         bouncesz = host->max_blk_count * 512;
148
149                 if (bouncesz > 512) {
150                         mq->bounce_buf = kmalloc(bouncesz, GFP_KERNEL);
151                         if (!mq->bounce_buf) {
152                                 printk(KERN_WARNING "%s: unable to "
153                                         "allocate bounce buffer\n",
154                                         mmc_card_name(card));
155                         }
156                 }
157
158                 if (mq->bounce_buf) {
159                         blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_ANY);
160                         blk_queue_max_sectors(mq->queue, bouncesz / 512);
161                         blk_queue_max_phys_segments(mq->queue, bouncesz / 512);
162                         blk_queue_max_hw_segments(mq->queue, bouncesz / 512);
163                         blk_queue_max_segment_size(mq->queue, bouncesz);
164
165                         mq->sg = kmalloc(sizeof(struct scatterlist),
166                                 GFP_KERNEL);
167                         if (!mq->sg) {
168                                 ret = -ENOMEM;
169                                 goto cleanup_queue;
170                         }
171                         sg_init_table(mq->sg, 1);
172
173                         mq->bounce_sg = kmalloc(sizeof(struct scatterlist) *
174                                 bouncesz / 512, GFP_KERNEL);
175                         if (!mq->bounce_sg) {
176                                 ret = -ENOMEM;
177                                 goto cleanup_queue;
178                         }
179                         sg_init_table(mq->bounce_sg, bouncesz / 512);
180                 }
181         }
182 #endif
183
184         if (!mq->bounce_buf) {
185                 blk_queue_bounce_limit(mq->queue, limit);
186                 blk_queue_max_sectors(mq->queue,
187                         min(host->max_blk_count, host->max_req_size / 512));
188                 blk_queue_max_phys_segments(mq->queue, host->max_phys_segs);
189                 blk_queue_max_hw_segments(mq->queue, host->max_hw_segs);
190                 blk_queue_max_segment_size(mq->queue, host->max_seg_size);
191
192                 mq->sg = kmalloc(sizeof(struct scatterlist) *
193                         host->max_phys_segs, GFP_KERNEL);
194                 if (!mq->sg) {
195                         ret = -ENOMEM;
196                         goto cleanup_queue;
197                 }
198                 sg_init_table(mq->sg, host->max_phys_segs);
199         }
200
201         init_MUTEX(&mq->thread_sem);
202
203         mq->thread = kthread_run(mmc_queue_thread, mq, "mmcqd");
204         if (IS_ERR(mq->thread)) {
205                 ret = PTR_ERR(mq->thread);
206                 goto free_bounce_sg;
207         }
208
209         return 0;
210  free_bounce_sg:
211         if (mq->bounce_sg)
212                 kfree(mq->bounce_sg);
213         mq->bounce_sg = NULL;
214  cleanup_queue:
215         if (mq->sg)
216                 kfree(mq->sg);
217         mq->sg = NULL;
218         if (mq->bounce_buf)
219                 kfree(mq->bounce_buf);
220         mq->bounce_buf = NULL;
221         blk_cleanup_queue(mq->queue);
222         return ret;
223 }
224
225 void mmc_cleanup_queue(struct mmc_queue *mq)
226 {
227         struct request_queue *q = mq->queue;
228         unsigned long flags;
229
230         /* Mark that we should start throwing out stragglers */
231         spin_lock_irqsave(q->queue_lock, flags);
232         q->queuedata = NULL;
233         spin_unlock_irqrestore(q->queue_lock, flags);
234
235         /* Make sure the queue isn't suspended, as that will deadlock */
236         mmc_queue_resume(mq);
237
238         /* Then terminate our worker thread */
239         kthread_stop(mq->thread);
240
241         if (mq->bounce_sg)
242                 kfree(mq->bounce_sg);
243         mq->bounce_sg = NULL;
244
245         kfree(mq->sg);
246         mq->sg = NULL;
247
248         if (mq->bounce_buf)
249                 kfree(mq->bounce_buf);
250         mq->bounce_buf = NULL;
251
252         blk_cleanup_queue(mq->queue);
253
254         mq->card = NULL;
255 }
256 EXPORT_SYMBOL(mmc_cleanup_queue);
257
258 /**
259  * mmc_queue_suspend - suspend a MMC request queue
260  * @mq: MMC queue to suspend
261  *
262  * Stop the block request queue, and wait for our thread to
263  * complete any outstanding requests.  This ensures that we
264  * won't suspend while a request is being processed.
265  */
266 void mmc_queue_suspend(struct mmc_queue *mq)
267 {
268         struct request_queue *q = mq->queue;
269         unsigned long flags;
270
271         if (!(mq->flags & MMC_QUEUE_SUSPENDED)) {
272                 mq->flags |= MMC_QUEUE_SUSPENDED;
273
274                 spin_lock_irqsave(q->queue_lock, flags);
275                 blk_stop_queue(q);
276                 spin_unlock_irqrestore(q->queue_lock, flags);
277
278                 down(&mq->thread_sem);
279         }
280 }
281
282 /**
283  * mmc_queue_resume - resume a previously suspended MMC request queue
284  * @mq: MMC queue to resume
285  */
286 void mmc_queue_resume(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                 up(&mq->thread_sem);
295
296                 spin_lock_irqsave(q->queue_lock, flags);
297                 blk_start_queue(q);
298                 spin_unlock_irqrestore(q->queue_lock, flags);
299         }
300 }
301
302 /*
303  * Prepare the sg list(s) to be handed of to the host driver
304  */
305 unsigned int mmc_queue_map_sg(struct mmc_queue *mq)
306 {
307         unsigned int sg_len;
308         size_t buflen;
309         struct scatterlist *sg;
310         int i;
311
312         if (!mq->bounce_buf)
313                 return blk_rq_map_sg(mq->queue, mq->req, mq->sg);
314
315         BUG_ON(!mq->bounce_sg);
316
317         sg_len = blk_rq_map_sg(mq->queue, mq->req, mq->bounce_sg);
318
319         mq->bounce_sg_len = sg_len;
320
321         buflen = 0;
322         for_each_sg(mq->bounce_sg, sg, sg_len, i)
323                 buflen += sg->length;
324
325         sg_init_one(mq->sg, mq->bounce_buf, buflen);
326
327         return 1;
328 }
329
330 /*
331  * If writing, bounce the data to the buffer before the request
332  * is sent to the host driver
333  */
334 void mmc_queue_bounce_pre(struct mmc_queue *mq)
335 {
336         unsigned long flags;
337
338         if (!mq->bounce_buf)
339                 return;
340
341         if (rq_data_dir(mq->req) != WRITE)
342                 return;
343
344         local_irq_save(flags);
345         sg_copy_to_buffer(mq->bounce_sg, mq->bounce_sg_len,
346                 mq->bounce_buf, mq->sg[0].length);
347         local_irq_restore(flags);
348 }
349
350 /*
351  * If reading, bounce the data from the buffer after the request
352  * has been handled by the host driver
353  */
354 void mmc_queue_bounce_post(struct mmc_queue *mq)
355 {
356         unsigned long flags;
357
358         if (!mq->bounce_buf)
359                 return;
360
361         if (rq_data_dir(mq->req) != READ)
362                 return;
363
364         local_irq_save(flags);
365         sg_copy_from_buffer(mq->bounce_sg, mq->bounce_sg_len,
366                 mq->bounce_buf, mq->sg[0].length);
367         local_irq_restore(flags);
368 }
369