aboutsummaryrefslogtreecommitdiff
path: root/drivers/mmc/card/queue.c
blob: c9a289c6c1391326c9fe19d26f4f6c5b55afd99d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
/*
 *  linux/drivers/mmc/card/queue.c
 *
 *  Copyright (C) 2003 Russell King, All Rights Reserved.
 *  Copyright 2006-2007 Pierre Ossman
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */
#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/freezer.h>
#include <linux/kthread.h>

#include <linux/mmc/card.h>
#include <linux/mmc/host.h>
#include "queue.h"

#define MMC_QUEUE_BOUNCESZ	65536

#define MMC_QUEUE_SUSPENDED	(1 << 0)

/*
 * Prepare a MMC request. This just filters out odd stuff.
 */
static int mmc_prep_request(struct request_queue *q, struct request *req)
{
	/*
	 * We only like normal block requests.
	 */
	if (!blk_fs_request(req) && !blk_pc_request(req)) {
		blk_dump_rq_flags(req, "MMC bad request");
		return BLKPREP_KILL;
	}

	req->cmd_flags |= REQ_DONTPREP;

	return BLKPREP_OK;
}

static int mmc_queue_thread(void *d)
{
	struct mmc_queue *mq = d;
	struct request_queue *q = mq->queue;

	current->flags |= PF_MEMALLOC;

	down(&mq->thread_sem);
	do {
		struct request *req = NULL;

		spin_lock_irq(q->queue_lock);
		set_current_state(TASK_INTERRUPTIBLE);
		if (!blk_queue_plugged(q))
			req = elv_next_request(q);
		mq->req = req;
		spin_unlock_irq(q->queue_lock);

		if (!req) {
			if (kthread_should_stop()) {
				set_current_state(TASK_RUNNING);
				break;
			}
			up(&mq->thread_sem);
			schedule();
			down(&mq->thread_sem);
			continue;
		}
		set_current_state(TASK_RUNNING);

		mq->issue_fn(mq, req);
	} while (1);
	up(&mq->thread_sem);

	return 0;
}

/*
 * Generic MMC request handler.  This is called for any queue on a
 * particular host.  When the host is not busy, we look for a request
 * on any queue on this host, and attempt to issue it.  This may
 * not be the queue we were asked to process.
 */
static void mmc_request(struct request_queue *q)
{
	struct mmc_queue *mq = q->queuedata;
	struct request *req;
	int ret;

	if (!mq) {
		printk(KERN_ERR "MMC: killing requests for dead queue\n");
		while ((req = elv_next_request(q)) != NULL) {
			do {
				ret = end_that_request_chunk(req, 0,
					req->current_nr_sectors << 9);
			} while (ret);
		}
		return;
	}

	if (!mq->req)
		wake_up_process(mq->thread);
}

/**
 * mmc_init_queue - initialise a queue structure.
 * @mq: mmc queue
 * @card: mmc card to attach this queue
 * @lock: queue lock
 *
 * Initialise a MMC card request queue.
 */
int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card, spinlock_t *lock)
{
	struct mmc_host *host = card->host;
	u64 limit = BLK_BOUNCE_HIGH;
	int ret;
	unsigned int bouncesz;

	if (mmc_dev(host)->dma_mask && *mmc_dev(host)->dma_mask)
		limit = *mmc_dev(host)->dma_mask;

	mq->card = card;
	mq->queue = blk_init_queue(mmc_request, lock);
	if (!mq->queue)
		return -ENOMEM;

	mq->queue->queuedata = mq;
	mq->req = NULL;

	blk_queue_prep_rq(mq->queue, mmc_prep_request);

#ifdef CONFIG_MMC_BLOCK_BOUNCE
	if (host->max_hw_segs == 1) {
		bouncesz = MMC_QUEUE_BOUNCESZ;

		if (bouncesz > host->max_req_size)
			bouncesz = host->max_req_size;
		if (bouncesz > host->max_seg_size)
			bouncesz = host->max_seg_size;

		mq->bounce_buf = kmalloc(bouncesz, GFP_KERNEL);
		if (!mq->bounce_buf) {
			printk(KERN_WARNING "%s: unable to allocate "
				"bounce buffer\n", mmc_card_name(card));
		} else {
			blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_HIGH);
			blk_queue_max_sectors(mq->queue, bouncesz / 512);
			blk_queue_max_phys_segments(mq->queue, bouncesz / 512);
			blk_queue_max_hw_segments(mq->queue, bouncesz / 512);
			blk_queue_max_segment_size(mq->queue, bouncesz);

			mq->sg = kmalloc(sizeof(struct scatterlist),
				GFP_KERNEL);
			if (!mq->sg) {
				ret = -ENOMEM;
				goto free_bounce_buf;
			}

			mq->bounce_sg = kmalloc(sizeof(struct scatterlist) *
				bouncesz / 512, GFP_KERNEL);
			if (!mq->bounce_sg) {
				ret = -ENOMEM;
				goto free_sg;
			}
		}
	}
#endif

	if (!mq->bounce_buf) {
		blk_queue_bounce_limit(mq->queue, limit);
		blk_queue_max_sectors(mq->queue, host->max_req_size / 512);
		blk_queue_max_phys_segments(mq->queue, host->max_phys_segs);
		blk_queue_max_hw_segments(mq->queue, host->max_hw_segs);
		blk_queue_max_segment_size(mq->queue, host->max_seg_size);

		mq->sg = kmalloc(sizeof(struct scatterlist) *
			host->max_phys_segs, GFP_KERNEL);
		if (!mq->sg) {
			ret = -ENOMEM;
			goto cleanup_queue;
		}
	}

	init_MUTEX(&mq->thread_sem);

	mq->thread = kthread_run(mmc_queue_thread, mq, "mmcqd");
	if (IS_ERR(mq->thread)) {
		ret = PTR_ERR(mq->thread);
		goto free_bounce_sg;
	}

	return 0;
 free_bounce_sg:
 	if (mq->bounce_sg)
 		kfree(mq->bounce_sg);
 	mq->bounce_sg = NULL;
 free_sg:
	kfree(mq->sg);
	mq->sg = NULL;
 free_bounce_buf:
	if (mq->bounce_buf)
		kfree(mq->bounce_buf);
	mq->bounce_buf = NULL;
 cleanup_queue:
	blk_cleanup_queue(mq->queue);
	return ret;
}

void mmc_cleanup_queue(struct mmc_queue *mq)
{
	struct request_queue *q = mq->queue;
	unsigned long flags;

	/* Mark that we should start throwing out stragglers */
	spin_lock_irqsave(q->queue_lock, flags);
	q->queuedata = NULL;
	spin_unlock_irqrestore(q->queue_lock, flags);

	/* Make sure the queue isn't suspended, as that will deadlock */
	mmc_queue_resume(mq);

	/* Then terminate our worker thread */
	kthread_stop(mq->thread);

 	if (mq->bounce_sg)
 		kfree(mq->bounce_sg);
 	mq->bounce_sg = NULL;

	kfree(mq->sg);
	mq->sg = NULL;

	if (mq->bounce_buf)
		kfree(mq->bounce_buf);
	mq->bounce_buf = NULL;

	blk_cleanup_queue(mq->queue);

	mq->card = NULL;
}
EXPORT_SYMBOL(mmc_cleanup_queue);

/**
 * mmc_queue_suspend - suspend a MMC request queue
 * @mq: MMC queue to suspend
 *
 * Stop the block request queue, and wait for our thread to
 * complete any outstanding requests.  This ensures that we
 * won't suspend while a request is being processed.
 */
void mmc_queue_suspend(struct mmc_queue *mq)
{
	struct request_queue *q = mq->queue;
	unsigned long flags;

	if (!(mq->flags & MMC_QUEUE_SUSPENDED)) {
		mq->flags |= MMC_QUEUE_SUSPENDED;

		spin_lock_irqsave(q->queue_lock, flags);
		blk_stop_queue(q);
		spin_unlock_irqrestore(q->queue_lock, flags);

		down(&mq->thread_sem);
	}
}

/**
 * mmc_queue_resume - resume a previously suspended MMC request queue
 * @mq: MMC queue to resume
 */
void mmc_queue_resume(struct mmc_queue *mq)
{
	struct request_queue *q = mq->queue;
	unsigned long flags;

	if (mq->flags & MMC_QUEUE_SUSPENDED) {
		mq->flags &= ~MMC_QUEUE_SUSPENDED;

		up(&mq->thread_sem);

		spin_lock_irqsave(q->queue_lock, flags);
		blk_start_queue(q);
		spin_unlock_irqrestore(q->queue_lock, flags);
	}
}

static void copy_sg(struct scatterlist *dst, unsigned int dst_len,
	struct scatterlist *src, unsigned int src_len)
{
	unsigned int chunk;
	char *dst_buf, *src_buf;
	unsigned int dst_size, src_size;

	dst_buf = NULL;
	src_buf = NULL;
	dst_size = 0;
	src_size = 0;

	while (src_len) {
		BUG_ON(dst_len == 0);

		if (dst_size == 0) {
			dst_buf = page_address(dst->page) + dst->offset;
			dst_size = dst->length;
		}

		if (src_size == 0) {
			src_buf = page_address(src->page) + src->offset;
			src_size = src->length;
		}

		chunk = min(dst_size, src_size);

		memcpy(dst_buf, src_buf, chunk);

		dst_buf += chunk;
		src_buf += chunk;
		dst_size -= chunk;
		src_size -= chunk;

		if (dst_size == 0) {
			dst++;
			dst_len--;
		}

		if (src_size == 0) {
			src++;
			src_len--;
		}
	}
}

unsigned int mmc_queue_map_sg(struct mmc_queue *mq)
{
	unsigned int sg_len;

	if (!mq->bounce_buf)
		return blk_rq_map_sg(mq->queue, mq->req, mq->sg);

	BUG_ON(!mq->bounce_sg);

	sg_len = blk_rq_map_sg(mq->queue, mq->req, mq->bounce_sg);

	mq->bounce_sg_len = sg_len;

	/*
	 * Shortcut in the event we only get a single entry.
	 */
	if (sg_len == 1) {
		memcpy(mq->sg, mq->bounce_sg, sizeof(struct scatterlist));
		return 1;
	}

	mq->sg[0].page = virt_to_page(mq->bounce_buf);
	mq->sg[0].offset = offset_in_page(mq->bounce_buf);
	mq->sg[0].length = 0;

	while (sg_len) {
		mq->sg[0].length += mq->bounce_sg[sg_len - 1].length;
		sg_len--;
	}

	return 1;
}

void mmc_queue_bounce_pre(struct mmc_queue *mq)
{
	if (!mq->bounce_buf)
		return;

	if (mq->bounce_sg_len == 1)
		return;
	if (rq_data_dir(mq->req) != WRITE)
		return;

	copy_sg(mq->sg, 1, mq->bounce_sg, mq->bounce_sg_len);
}

void mmc_queue_bounce_post(struct mmc_queue *mq)
{
	if (!mq->bounce_buf)
		return;

	if (mq->bounce_sg_len == 1)
		return;
	if (rq_data_dir(mq->req) != READ)
		return;

	copy_sg(mq->bounce_sg, mq->bounce_sg_len, mq->sg, 1);
}