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 */
mmc_prep_request(struct request_queue * q,struct request * req)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
mmc_queue_thread(void * d)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 */
mmc_request(struct request_queue * q)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 */
mmc_init_queue(struct mmc_queue * mq,struct mmc_card * card,spinlock_t * lock)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 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, mq->queue);
131 if (mmc_can_erase(card)) {
132 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mq->queue);
133 mq->queue->limits.max_discard_sectors = UINT_MAX;
134 if (card->erased_byte == 0)
135 mq->queue->limits.discard_zeroes_data = 1;
136 if (!mmc_can_trim(card) && is_power_of_2(card->erase_size)) {
137 mq->queue->limits.discard_granularity =
138 card->erase_size << 9;
139 mq->queue->limits.discard_alignment =
140 card->erase_size << 9;
141 }
142 if (mmc_can_secure_erase_trim(card))
143 queue_flag_set_unlocked(QUEUE_FLAG_SECDISCARD,
144 mq->queue);
145 }
146
147 #ifdef CONFIG_MMC_BLOCK_BOUNCE
148 if (host->max_segs == 1) {
149 unsigned int bouncesz;
150
151 bouncesz = MMC_QUEUE_BOUNCESZ;
152
153 if (bouncesz > host->max_req_size)
154 bouncesz = host->max_req_size;
155 if (bouncesz > host->max_seg_size)
156 bouncesz = host->max_seg_size;
157 if (bouncesz > (host->max_blk_count * 512))
158 bouncesz = host->max_blk_count * 512;
159
160 if (bouncesz > 512) {
161 mq->bounce_buf = kmalloc(bouncesz, GFP_KERNEL);
162 if (!mq->bounce_buf) {
163 printk(KERN_WARNING "%s: unable to "
164 "allocate bounce buffer\n",
165 mmc_card_name(card));
166 }
167 }
168
169 if (mq->bounce_buf) {
170 blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_ANY);
171 blk_queue_max_hw_sectors(mq->queue, bouncesz / 512);
172 blk_queue_max_segments(mq->queue, bouncesz / 512);
173 blk_queue_max_segment_size(mq->queue, bouncesz);
174
175 mq->sg = kmalloc(sizeof(struct scatterlist),
176 GFP_KERNEL);
177 if (!mq->sg) {
178 ret = -ENOMEM;
179 goto cleanup_queue;
180 }
181 sg_init_table(mq->sg, 1);
182
183 mq->bounce_sg = kmalloc(sizeof(struct scatterlist) *
184 bouncesz / 512, GFP_KERNEL);
185 if (!mq->bounce_sg) {
186 ret = -ENOMEM;
187 goto cleanup_queue;
188 }
189 sg_init_table(mq->bounce_sg, bouncesz / 512);
190 }
191 }
192 #endif
193
194 if (!mq->bounce_buf) {
195 blk_queue_bounce_limit(mq->queue, limit);
196 blk_queue_max_hw_sectors(mq->queue,
197 min(host->max_blk_count, host->max_req_size / 512));
198 blk_queue_max_segments(mq->queue, host->max_segs);
199 blk_queue_max_segment_size(mq->queue, host->max_seg_size);
200
201 mq->sg = kmalloc(sizeof(struct scatterlist) *
202 host->max_segs, GFP_KERNEL);
203 if (!mq->sg) {
204 ret = -ENOMEM;
205 goto cleanup_queue;
206 }
207 sg_init_table(mq->sg, host->max_segs);
208 }
209
210 sema_init(&mq->thread_sem, 1);
211
212 mq->thread = kthread_run(mmc_queue_thread, mq, "mmcqd/%d",
213 host->index);
214
215 if (IS_ERR(mq->thread)) {
216 ret = PTR_ERR(mq->thread);
217 goto free_bounce_sg;
218 }
219
220 return 0;
221 free_bounce_sg:
222 if (mq->bounce_sg)
223 kfree(mq->bounce_sg);
224 mq->bounce_sg = NULL;
225 cleanup_queue:
226 if (mq->sg)
227 kfree(mq->sg);
228 mq->sg = NULL;
229 if (mq->bounce_buf)
230 kfree(mq->bounce_buf);
231 mq->bounce_buf = NULL;
232 blk_cleanup_queue(mq->queue);
233 return ret;
234 }
235
mmc_cleanup_queue(struct mmc_queue * mq)236 void mmc_cleanup_queue(struct mmc_queue *mq)
237 {
238 struct request_queue *q = mq->queue;
239 unsigned long flags;
240
241 /* Make sure the queue isn't suspended, as that will deadlock */
242 mmc_queue_resume(mq);
243
244 /* Then terminate our worker thread */
245 kthread_stop(mq->thread);
246
247 /* Empty the queue */
248 spin_lock_irqsave(q->queue_lock, flags);
249 q->queuedata = NULL;
250 blk_start_queue(q);
251 spin_unlock_irqrestore(q->queue_lock, flags);
252
253 if (mq->bounce_sg)
254 kfree(mq->bounce_sg);
255 mq->bounce_sg = NULL;
256
257 kfree(mq->sg);
258 mq->sg = NULL;
259
260 if (mq->bounce_buf)
261 kfree(mq->bounce_buf);
262 mq->bounce_buf = NULL;
263
264 mq->card = NULL;
265 }
266 EXPORT_SYMBOL(mmc_cleanup_queue);
267
268 /**
269 * mmc_queue_suspend - suspend a MMC request queue
270 * @mq: MMC queue to suspend
271 *
272 * Stop the block request queue, and wait for our thread to
273 * complete any outstanding requests. This ensures that we
274 * won't suspend while a request is being processed.
275 */
mmc_queue_suspend(struct mmc_queue * mq)276 void mmc_queue_suspend(struct mmc_queue *mq)
277 {
278 struct request_queue *q = mq->queue;
279 unsigned long flags;
280
281 if (!(mq->flags & MMC_QUEUE_SUSPENDED)) {
282 mq->flags |= MMC_QUEUE_SUSPENDED;
283
284 spin_lock_irqsave(q->queue_lock, flags);
285 blk_stop_queue(q);
286 spin_unlock_irqrestore(q->queue_lock, flags);
287
288 down(&mq->thread_sem);
289 }
290 }
291
292 /**
293 * mmc_queue_resume - resume a previously suspended MMC request queue
294 * @mq: MMC queue to resume
295 */
mmc_queue_resume(struct mmc_queue * mq)296 void mmc_queue_resume(struct mmc_queue *mq)
297 {
298 struct request_queue *q = mq->queue;
299 unsigned long flags;
300
301 if (mq->flags & MMC_QUEUE_SUSPENDED) {
302 mq->flags &= ~MMC_QUEUE_SUSPENDED;
303
304 up(&mq->thread_sem);
305
306 spin_lock_irqsave(q->queue_lock, flags);
307 blk_start_queue(q);
308 spin_unlock_irqrestore(q->queue_lock, flags);
309 }
310 }
311
312 /*
313 * Prepare the sg list(s) to be handed of to the host driver
314 */
mmc_queue_map_sg(struct mmc_queue * mq)315 unsigned int mmc_queue_map_sg(struct mmc_queue *mq)
316 {
317 unsigned int sg_len;
318 size_t buflen;
319 struct scatterlist *sg;
320 int i;
321
322 if (!mq->bounce_buf)
323 return blk_rq_map_sg(mq->queue, mq->req, mq->sg);
324
325 BUG_ON(!mq->bounce_sg);
326
327 sg_len = blk_rq_map_sg(mq->queue, mq->req, mq->bounce_sg);
328
329 mq->bounce_sg_len = sg_len;
330
331 buflen = 0;
332 for_each_sg(mq->bounce_sg, sg, sg_len, i)
333 buflen += sg->length;
334
335 sg_init_one(mq->sg, mq->bounce_buf, buflen);
336
337 return 1;
338 }
339
340 /*
341 * If writing, bounce the data to the buffer before the request
342 * is sent to the host driver
343 */
mmc_queue_bounce_pre(struct mmc_queue * mq)344 void mmc_queue_bounce_pre(struct mmc_queue *mq)
345 {
346 unsigned long flags;
347
348 if (!mq->bounce_buf)
349 return;
350
351 if (rq_data_dir(mq->req) != WRITE)
352 return;
353
354 local_irq_save(flags);
355 sg_copy_to_buffer(mq->bounce_sg, mq->bounce_sg_len,
356 mq->bounce_buf, mq->sg[0].length);
357 local_irq_restore(flags);
358 }
359
360 /*
361 * If reading, bounce the data from the buffer after the request
362 * has been handled by the host driver
363 */
mmc_queue_bounce_post(struct mmc_queue * mq)364 void mmc_queue_bounce_post(struct mmc_queue *mq)
365 {
366 unsigned long flags;
367
368 if (!mq->bounce_buf)
369 return;
370
371 if (rq_data_dir(mq->req) != READ)
372 return;
373
374 local_irq_save(flags);
375 sg_copy_from_buffer(mq->bounce_sg, mq->bounce_sg_len,
376 mq->bounce_buf, mq->sg[0].length);
377 local_irq_restore(flags);
378 }
379
380