xref: /linux/drivers/mmc/core/queue.c (revision e5c86679d5e864947a52fb31e45a425dea3e7fa9) 
1 /*
2  *  Copyright (C) 2003 Russell King, All Rights Reserved.
3  *  Copyright 2006-2007 Pierre Ossman
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License version 2 as
7  * published by the Free Software Foundation.
8  *
9  */
10 #include <linux/slab.h>
11 #include <linux/module.h>
12 #include <linux/blkdev.h>
13 #include <linux/freezer.h>
14 #include <linux/kthread.h>
15 #include <linux/scatterlist.h>
16 #include <linux/dma-mapping.h>
17 
18 #include <linux/mmc/card.h>
19 #include <linux/mmc/host.h>
20 
21 #include "queue.h"
22 #include "block.h"
23 #include "core.h"
24 #include "card.h"
25 
26 #define MMC_QUEUE_BOUNCESZ	65536
27 
28 /*
29  * Prepare a MMC request. This just filters out odd stuff.
30  */
31 static int mmc_prep_request(struct request_queue *q, struct request *req)
32 {
33 	struct mmc_queue *mq = q->queuedata;
34 
35 	if (mq && (mmc_card_removed(mq->card) || mmc_access_rpmb(mq)))
36 		return BLKPREP_KILL;
37 
38 	req->rq_flags |= RQF_DONTPREP;
39 
40 	return BLKPREP_OK;
41 }
42 
43 static int mmc_queue_thread(void *d)
44 {
45 	struct mmc_queue *mq = d;
46 	struct request_queue *q = mq->queue;
47 	struct mmc_context_info *cntx = &mq->card->host->context_info;
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 		req = blk_fetch_request(q);
58 		mq->asleep = false;
59 		cntx->is_waiting_last_req = false;
60 		cntx->is_new_req = false;
61 		if (!req) {
62 			/*
63 			 * Dispatch queue is empty so set flags for
64 			 * mmc_request_fn() to wake us up.
65 			 */
66 			if (mq->mqrq_prev->req)
67 				cntx->is_waiting_last_req = true;
68 			else
69 				mq->asleep = true;
70 		}
71 		mq->mqrq_cur->req = req;
72 		spin_unlock_irq(q->queue_lock);
73 
74 		if (req || mq->mqrq_prev->req) {
75 			bool req_is_special = mmc_req_is_special(req);
76 
77 			set_current_state(TASK_RUNNING);
78 			mmc_blk_issue_rq(mq, req);
79 			cond_resched();
80 			if (mq->new_request) {
81 				mq->new_request = false;
82 				continue; /* fetch again */
83 			}
84 
85 			/*
86 			 * Current request becomes previous request
87 			 * and vice versa.
88 			 * In case of special requests, current request
89 			 * has been finished. Do not assign it to previous
90 			 * request.
91 			 */
92 			if (req_is_special)
93 				mq->mqrq_cur->req = NULL;
94 
95 			mq->mqrq_prev->brq.mrq.data = NULL;
96 			mq->mqrq_prev->req = NULL;
97 			swap(mq->mqrq_prev, mq->mqrq_cur);
98 		} else {
99 			if (kthread_should_stop()) {
100 				set_current_state(TASK_RUNNING);
101 				break;
102 			}
103 			up(&mq->thread_sem);
104 			schedule();
105 			down(&mq->thread_sem);
106 		}
107 	} while (1);
108 	up(&mq->thread_sem);
109 
110 	return 0;
111 }
112 
113 /*
114  * Generic MMC request handler.  This is called for any queue on a
115  * particular host.  When the host is not busy, we look for a request
116  * on any queue on this host, and attempt to issue it.  This may
117  * not be the queue we were asked to process.
118  */
119 static void mmc_request_fn(struct request_queue *q)
120 {
121 	struct mmc_queue *mq = q->queuedata;
122 	struct request *req;
123 	struct mmc_context_info *cntx;
124 
125 	if (!mq) {
126 		while ((req = blk_fetch_request(q)) != NULL) {
127 			req->rq_flags |= RQF_QUIET;
128 			__blk_end_request_all(req, -EIO);
129 		}
130 		return;
131 	}
132 
133 	cntx = &mq->card->host->context_info;
134 
135 	if (cntx->is_waiting_last_req) {
136 		cntx->is_new_req = true;
137 		wake_up_interruptible(&cntx->wait);
138 	}
139 
140 	if (mq->asleep)
141 		wake_up_process(mq->thread);
142 }
143 
144 static struct scatterlist *mmc_alloc_sg(int sg_len, int *err)
145 {
146 	struct scatterlist *sg;
147 
148 	sg = kmalloc_array(sg_len, sizeof(*sg), GFP_KERNEL);
149 	if (!sg)
150 		*err = -ENOMEM;
151 	else {
152 		*err = 0;
153 		sg_init_table(sg, sg_len);
154 	}
155 
156 	return sg;
157 }
158 
159 static void mmc_queue_setup_discard(struct request_queue *q,
160 				    struct mmc_card *card)
161 {
162 	unsigned max_discard;
163 
164 	max_discard = mmc_calc_max_discard(card);
165 	if (!max_discard)
166 		return;
167 
168 	queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
169 	blk_queue_max_discard_sectors(q, max_discard);
170 	if (card->erased_byte == 0 && !mmc_can_discard(card))
171 		q->limits.discard_zeroes_data = 1;
172 	q->limits.discard_granularity = card->pref_erase << 9;
173 	/* granularity must not be greater than max. discard */
174 	if (card->pref_erase > max_discard)
175 		q->limits.discard_granularity = 0;
176 	if (mmc_can_secure_erase_trim(card))
177 		queue_flag_set_unlocked(QUEUE_FLAG_SECERASE, q);
178 }
179 
180 #ifdef CONFIG_MMC_BLOCK_BOUNCE
181 static bool mmc_queue_alloc_bounce_bufs(struct mmc_queue *mq,
182 					unsigned int bouncesz)
183 {
184 	int i;
185 
186 	for (i = 0; i < mq->qdepth; i++) {
187 		mq->mqrq[i].bounce_buf = kmalloc(bouncesz, GFP_KERNEL);
188 		if (!mq->mqrq[i].bounce_buf)
189 			goto out_err;
190 	}
191 
192 	return true;
193 
194 out_err:
195 	while (--i >= 0) {
196 		kfree(mq->mqrq[i].bounce_buf);
197 		mq->mqrq[i].bounce_buf = NULL;
198 	}
199 	pr_warn("%s: unable to allocate bounce buffers\n",
200 		mmc_card_name(mq->card));
201 	return false;
202 }
203 
204 static int mmc_queue_alloc_bounce_sgs(struct mmc_queue *mq,
205 				      unsigned int bouncesz)
206 {
207 	int i, ret;
208 
209 	for (i = 0; i < mq->qdepth; i++) {
210 		mq->mqrq[i].sg = mmc_alloc_sg(1, &ret);
211 		if (ret)
212 			return ret;
213 
214 		mq->mqrq[i].bounce_sg = mmc_alloc_sg(bouncesz / 512, &ret);
215 		if (ret)
216 			return ret;
217 	}
218 
219 	return 0;
220 }
221 #endif
222 
223 static int mmc_queue_alloc_sgs(struct mmc_queue *mq, int max_segs)
224 {
225 	int i, ret;
226 
227 	for (i = 0; i < mq->qdepth; i++) {
228 		mq->mqrq[i].sg = mmc_alloc_sg(max_segs, &ret);
229 		if (ret)
230 			return ret;
231 	}
232 
233 	return 0;
234 }
235 
236 static void mmc_queue_req_free_bufs(struct mmc_queue_req *mqrq)
237 {
238 	kfree(mqrq->bounce_sg);
239 	mqrq->bounce_sg = NULL;
240 
241 	kfree(mqrq->sg);
242 	mqrq->sg = NULL;
243 
244 	kfree(mqrq->bounce_buf);
245 	mqrq->bounce_buf = NULL;
246 }
247 
248 static void mmc_queue_reqs_free_bufs(struct mmc_queue *mq)
249 {
250 	int i;
251 
252 	for (i = 0; i < mq->qdepth; i++)
253 		mmc_queue_req_free_bufs(&mq->mqrq[i]);
254 }
255 
256 /**
257  * mmc_init_queue - initialise a queue structure.
258  * @mq: mmc queue
259  * @card: mmc card to attach this queue
260  * @lock: queue lock
261  * @subname: partition subname
262  *
263  * Initialise a MMC card request queue.
264  */
265 int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card,
266 		   spinlock_t *lock, const char *subname)
267 {
268 	struct mmc_host *host = card->host;
269 	u64 limit = BLK_BOUNCE_HIGH;
270 	bool bounce = false;
271 	int ret = -ENOMEM;
272 
273 	if (mmc_dev(host)->dma_mask && *mmc_dev(host)->dma_mask)
274 		limit = (u64)dma_max_pfn(mmc_dev(host)) << PAGE_SHIFT;
275 
276 	mq->card = card;
277 	mq->queue = blk_init_queue(mmc_request_fn, lock);
278 	if (!mq->queue)
279 		return -ENOMEM;
280 
281 	mq->qdepth = 2;
282 	mq->mqrq = kcalloc(mq->qdepth, sizeof(struct mmc_queue_req),
283 			   GFP_KERNEL);
284 	if (!mq->mqrq)
285 		goto blk_cleanup;
286 	mq->mqrq_cur = &mq->mqrq[0];
287 	mq->mqrq_prev = &mq->mqrq[1];
288 	mq->queue->queuedata = mq;
289 
290 	blk_queue_prep_rq(mq->queue, mmc_prep_request);
291 	queue_flag_set_unlocked(QUEUE_FLAG_NONROT, mq->queue);
292 	queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, mq->queue);
293 	if (mmc_can_erase(card))
294 		mmc_queue_setup_discard(mq->queue, card);
295 
296 #ifdef CONFIG_MMC_BLOCK_BOUNCE
297 	if (host->max_segs == 1) {
298 		unsigned int bouncesz;
299 
300 		bouncesz = MMC_QUEUE_BOUNCESZ;
301 
302 		if (bouncesz > host->max_req_size)
303 			bouncesz = host->max_req_size;
304 		if (bouncesz > host->max_seg_size)
305 			bouncesz = host->max_seg_size;
306 		if (bouncesz > (host->max_blk_count * 512))
307 			bouncesz = host->max_blk_count * 512;
308 
309 		if (bouncesz > 512 &&
310 		    mmc_queue_alloc_bounce_bufs(mq, bouncesz)) {
311 			blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_ANY);
312 			blk_queue_max_hw_sectors(mq->queue, bouncesz / 512);
313 			blk_queue_max_segments(mq->queue, bouncesz / 512);
314 			blk_queue_max_segment_size(mq->queue, bouncesz);
315 
316 			ret = mmc_queue_alloc_bounce_sgs(mq, bouncesz);
317 			if (ret)
318 				goto cleanup_queue;
319 			bounce = true;
320 		}
321 	}
322 #endif
323 
324 	if (!bounce) {
325 		blk_queue_bounce_limit(mq->queue, limit);
326 		blk_queue_max_hw_sectors(mq->queue,
327 			min(host->max_blk_count, host->max_req_size / 512));
328 		blk_queue_max_segments(mq->queue, host->max_segs);
329 		blk_queue_max_segment_size(mq->queue, host->max_seg_size);
330 
331 		ret = mmc_queue_alloc_sgs(mq, host->max_segs);
332 		if (ret)
333 			goto cleanup_queue;
334 	}
335 
336 	sema_init(&mq->thread_sem, 1);
337 
338 	mq->thread = kthread_run(mmc_queue_thread, mq, "mmcqd/%d%s",
339 		host->index, subname ? subname : "");
340 
341 	if (IS_ERR(mq->thread)) {
342 		ret = PTR_ERR(mq->thread);
343 		goto cleanup_queue;
344 	}
345 
346 	return 0;
347 
348  cleanup_queue:
349 	mmc_queue_reqs_free_bufs(mq);
350 	kfree(mq->mqrq);
351 	mq->mqrq = NULL;
352 blk_cleanup:
353 	blk_cleanup_queue(mq->queue);
354 	return ret;
355 }
356 
357 void mmc_cleanup_queue(struct mmc_queue *mq)
358 {
359 	struct request_queue *q = mq->queue;
360 	unsigned long flags;
361 
362 	/* Make sure the queue isn't suspended, as that will deadlock */
363 	mmc_queue_resume(mq);
364 
365 	/* Then terminate our worker thread */
366 	kthread_stop(mq->thread);
367 
368 	/* Empty the queue */
369 	spin_lock_irqsave(q->queue_lock, flags);
370 	q->queuedata = NULL;
371 	blk_start_queue(q);
372 	spin_unlock_irqrestore(q->queue_lock, flags);
373 
374 	mmc_queue_reqs_free_bufs(mq);
375 	kfree(mq->mqrq);
376 	mq->mqrq = NULL;
377 
378 	mq->card = NULL;
379 }
380 EXPORT_SYMBOL(mmc_cleanup_queue);
381 
382 /**
383  * mmc_queue_suspend - suspend a MMC request queue
384  * @mq: MMC queue to suspend
385  *
386  * Stop the block request queue, and wait for our thread to
387  * complete any outstanding requests.  This ensures that we
388  * won't suspend while a request is being processed.
389  */
390 void mmc_queue_suspend(struct mmc_queue *mq)
391 {
392 	struct request_queue *q = mq->queue;
393 	unsigned long flags;
394 
395 	if (!mq->suspended) {
396 		mq->suspended |= true;
397 
398 		spin_lock_irqsave(q->queue_lock, flags);
399 		blk_stop_queue(q);
400 		spin_unlock_irqrestore(q->queue_lock, flags);
401 
402 		down(&mq->thread_sem);
403 	}
404 }
405 
406 /**
407  * mmc_queue_resume - resume a previously suspended MMC request queue
408  * @mq: MMC queue to resume
409  */
410 void mmc_queue_resume(struct mmc_queue *mq)
411 {
412 	struct request_queue *q = mq->queue;
413 	unsigned long flags;
414 
415 	if (mq->suspended) {
416 		mq->suspended = false;
417 
418 		up(&mq->thread_sem);
419 
420 		spin_lock_irqsave(q->queue_lock, flags);
421 		blk_start_queue(q);
422 		spin_unlock_irqrestore(q->queue_lock, flags);
423 	}
424 }
425 
426 /*
427  * Prepare the sg list(s) to be handed of to the host driver
428  */
429 unsigned int mmc_queue_map_sg(struct mmc_queue *mq, struct mmc_queue_req *mqrq)
430 {
431 	unsigned int sg_len;
432 	size_t buflen;
433 	struct scatterlist *sg;
434 	int i;
435 
436 	if (!mqrq->bounce_buf)
437 		return blk_rq_map_sg(mq->queue, mqrq->req, mqrq->sg);
438 
439 	sg_len = blk_rq_map_sg(mq->queue, mqrq->req, mqrq->bounce_sg);
440 
441 	mqrq->bounce_sg_len = sg_len;
442 
443 	buflen = 0;
444 	for_each_sg(mqrq->bounce_sg, sg, sg_len, i)
445 		buflen += sg->length;
446 
447 	sg_init_one(mqrq->sg, mqrq->bounce_buf, buflen);
448 
449 	return 1;
450 }
451 
452 /*
453  * If writing, bounce the data to the buffer before the request
454  * is sent to the host driver
455  */
456 void mmc_queue_bounce_pre(struct mmc_queue_req *mqrq)
457 {
458 	if (!mqrq->bounce_buf)
459 		return;
460 
461 	if (rq_data_dir(mqrq->req) != WRITE)
462 		return;
463 
464 	sg_copy_to_buffer(mqrq->bounce_sg, mqrq->bounce_sg_len,
465 		mqrq->bounce_buf, mqrq->sg[0].length);
466 }
467 
468 /*
469  * If reading, bounce the data from the buffer after the request
470  * has been handled by the host driver
471  */
472 void mmc_queue_bounce_post(struct mmc_queue_req *mqrq)
473 {
474 	if (!mqrq->bounce_buf)
475 		return;
476 
477 	if (rq_data_dir(mqrq->req) != READ)
478 		return;
479 
480 	sg_copy_from_buffer(mqrq->bounce_sg, mqrq->bounce_sg_len,
481 		mqrq->bounce_buf, mqrq->sg[0].length);
482 }
483