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) && !blk_pc_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
135 #ifdef CONFIG_MMC_BLOCK_BOUNCE
136 if (host->max_hw_segs == 1) {
137 unsigned int bouncesz;
138
139 bouncesz = MMC_QUEUE_BOUNCESZ;
140
141 if (bouncesz > host->max_req_size)
142 bouncesz = host->max_req_size;
143 if (bouncesz > host->max_seg_size)
144 bouncesz = host->max_seg_size;
145
146 mq->bounce_buf = kmalloc(bouncesz, GFP_KERNEL);
147 if (!mq->bounce_buf) {
148 printk(KERN_WARNING "%s: unable to allocate "
149 "bounce buffer\n", mmc_card_name(card));
150 } else {
151 blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_HIGH);
152 blk_queue_max_sectors(mq->queue, bouncesz / 512);
153 blk_queue_max_phys_segments(mq->queue, bouncesz / 512);
154 blk_queue_max_hw_segments(mq->queue, bouncesz / 512);
155 blk_queue_max_segment_size(mq->queue, bouncesz);
156
157 mq->sg = kmalloc(sizeof(struct scatterlist),
158 GFP_KERNEL);
159 if (!mq->sg) {
160 ret = -ENOMEM;
161 goto cleanup_queue;
162 }
163 sg_init_table(mq->sg, 1);
164
165 mq->bounce_sg = kmalloc(sizeof(struct scatterlist) *
166 bouncesz / 512, GFP_KERNEL);
167 if (!mq->bounce_sg) {
168 ret = -ENOMEM;
169 goto cleanup_queue;
170 }
171 sg_init_table(mq->bounce_sg, bouncesz / 512);
172 }
173 }
174 #endif
175
176 if (!mq->bounce_buf) {
177 blk_queue_bounce_limit(mq->queue, limit);
178 blk_queue_max_sectors(mq->queue, host->max_req_size / 512);
179 blk_queue_max_phys_segments(mq->queue, host->max_phys_segs);
180 blk_queue_max_hw_segments(mq->queue, host->max_hw_segs);
181 blk_queue_max_segment_size(mq->queue, host->max_seg_size);
182
183 mq->sg = kmalloc(sizeof(struct scatterlist) *
184 host->max_phys_segs, GFP_KERNEL);
185 if (!mq->sg) {
186 ret = -ENOMEM;
187 goto cleanup_queue;
188 }
189 sg_init_table(mq->sg, host->max_phys_segs);
190 }
191
192 init_MUTEX(&mq->thread_sem);
193
194 mq->thread = kthread_run(mmc_queue_thread, mq, "mmcqd");
195 if (IS_ERR(mq->thread)) {
196 ret = PTR_ERR(mq->thread);
197 goto free_bounce_sg;
198 }
199
200 return 0;
201 free_bounce_sg:
202 if (mq->bounce_sg)
203 kfree(mq->bounce_sg);
204 mq->bounce_sg = NULL;
205 cleanup_queue:
206 if (mq->sg)
207 kfree(mq->sg);
208 mq->sg = NULL;
209 if (mq->bounce_buf)
210 kfree(mq->bounce_buf);
211 mq->bounce_buf = NULL;
212 blk_cleanup_queue(mq->queue);
213 return ret;
214 }
215
216 void mmc_cleanup_queue(struct mmc_queue *mq)
217 {
218 struct request_queue *q = mq->queue;
219 unsigned long flags;
220
221 /* Mark that we should start throwing out stragglers */
222 spin_lock_irqsave(q->queue_lock, flags);
223 q->queuedata = NULL;
224 spin_unlock_irqrestore(q->queue_lock, flags);
225
226 /* Make sure the queue isn't suspended, as that will deadlock */
227 mmc_queue_resume(mq);
228
229 /* Then terminate our worker thread */
230 kthread_stop(mq->thread);
231
232 if (mq->bounce_sg)
233 kfree(mq->bounce_sg);
234 mq->bounce_sg = NULL;
235
236 kfree(mq->sg);
237 mq->sg = NULL;
238
239 if (mq->bounce_buf)
240 kfree(mq->bounce_buf);
241 mq->bounce_buf = NULL;
242
243 blk_cleanup_queue(mq->queue);
244
245 mq->card = NULL;
246 }
247 EXPORT_SYMBOL(mmc_cleanup_queue);
248
249 /**
250 * mmc_queue_suspend - suspend a MMC request queue
251 * @mq: MMC queue to suspend
252 *
253 * Stop the block request queue, and wait for our thread to
254 * complete any outstanding requests. This ensures that we
255 * won't suspend while a request is being processed.
256 */
257 void mmc_queue_suspend(struct mmc_queue *mq)
258 {
259 struct request_queue *q = mq->queue;
260 unsigned long flags;
261
262 if (!(mq->flags & MMC_QUEUE_SUSPENDED)) {
263 mq->flags |= MMC_QUEUE_SUSPENDED;
264
265 spin_lock_irqsave(q->queue_lock, flags);
266 blk_stop_queue(q);
267 spin_unlock_irqrestore(q->queue_lock, flags);
268
269 down(&mq->thread_sem);
270 }
271 }
272
273 /**
274 * mmc_queue_resume - resume a previously suspended MMC request queue
275 * @mq: MMC queue to resume
276 */
277 void mmc_queue_resume(struct mmc_queue *mq)
278 {
279 struct request_queue *q = mq->queue;
280 unsigned long flags;
281
282 if (mq->flags & MMC_QUEUE_SUSPENDED) {
283 mq->flags &= ~MMC_QUEUE_SUSPENDED;
284
285 up(&mq->thread_sem);
286
287 spin_lock_irqsave(q->queue_lock, flags);
288 blk_start_queue(q);
289 spin_unlock_irqrestore(q->queue_lock, flags);
290 }
291 }
292
293 static void copy_sg(struct scatterlist *dst, unsigned int dst_len,
294 struct scatterlist *src, unsigned int src_len)
295 {
296 unsigned int chunk;
297 char *dst_buf, *src_buf;
298 unsigned int dst_size, src_size;
299
300 dst_buf = NULL;
301 src_buf = NULL;
302 dst_size = 0;
303 src_size = 0;
304
305 while (src_len) {
306 BUG_ON(dst_len == 0);
307
308 if (dst_size == 0) {
309 dst_buf = sg_virt(dst);
310 dst_size = dst->length;
311 }
312
313 if (src_size == 0) {
314 src_buf = sg_virt(src);
315 src_size = src->length;
316 }
317
318 chunk = min(dst_size, src_size);
319
320 memcpy(dst_buf, src_buf, chunk);
321
322 dst_buf += chunk;
323 src_buf += chunk;
324 dst_size -= chunk;
325 src_size -= chunk;
326
327 if (dst_size == 0) {
328 dst++;
329 dst_len--;
330 }
331
332 if (src_size == 0) {
333 src++;
334 src_len--;
335 }
336 }
337 }
338
339 unsigned int mmc_queue_map_sg(struct mmc_queue *mq)
340 {
341 unsigned int sg_len;
342
343 if (!mq->bounce_buf)
344 return blk_rq_map_sg(mq->queue, mq->req, mq->sg);
345
346 BUG_ON(!mq->bounce_sg);
347
348 sg_len = blk_rq_map_sg(mq->queue, mq->req, mq->bounce_sg);
349
350 mq->bounce_sg_len = sg_len;
351
352 /*
353 * Shortcut in the event we only get a single entry.
354 */
355 if (sg_len == 1) {
356 memcpy(mq->sg, mq->bounce_sg, sizeof(struct scatterlist));
357 return 1;
358 }
359
360 sg_init_one(mq->sg, mq->bounce_buf, 0);
361
362 while (sg_len) {
363 mq->sg[0].length += mq->bounce_sg[sg_len - 1].length;
364 sg_len--;
365 }
366
367 return 1;
368 }
369
370 void mmc_queue_bounce_pre(struct mmc_queue *mq)
371 {
372 if (!mq->bounce_buf)
373 return;
374
375 if (mq->bounce_sg_len == 1)
376 return;
377 if (rq_data_dir(mq->req) != WRITE)
378 return;
379
380 copy_sg(mq->sg, 1, mq->bounce_sg, mq->bounce_sg_len);
381 }
382
383 void mmc_queue_bounce_post(struct mmc_queue *mq)
384 {
385 if (!mq->bounce_buf)
386 return;
387
388 if (mq->bounce_sg_len == 1)
389 return;
390 if (rq_data_dir(mq->req) != READ)
391 return;
392
393 copy_sg(mq->bounce_sg, mq->bounce_sg_len, mq->sg, 1);
394 }
395
396
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