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