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 */
 30static int mmc_prep_request(struct request_queue *q, struct request *req)
 31{
 32	struct mmc_queue *mq = q->queuedata;
 33
 34	/*
 35	 * We only like normal block requests and discards.
 36	 */
 37	if (req->cmd_type != REQ_TYPE_FS && !(req->cmd_flags & REQ_DISCARD)) {
 38		blk_dump_rq_flags(req, "MMC bad request");
 39		return BLKPREP_KILL;
 40	}
 41
 42	if (mq && mmc_card_removed(mq->card))
 43		return BLKPREP_KILL;
 44
 45	req->cmd_flags |= REQ_DONTPREP;
 46
 47	return BLKPREP_OK;
 48}
 49
 50static int mmc_queue_thread(void *d)
 51{
 52	struct mmc_queue *mq = d;
 53	struct request_queue *q = mq->queue;
 54
 55	current->flags |= PF_MEMALLOC;
 56
 57	down(&mq->thread_sem);
 58	do {
 59		struct request *req = NULL;
 60		struct mmc_queue_req *tmp;
 61
 62		spin_lock_irq(q->queue_lock);
 63		set_current_state(TASK_INTERRUPTIBLE);
 64		req = blk_fetch_request(q);
 65		mq->mqrq_cur->req = req;
 66		spin_unlock_irq(q->queue_lock);
 67
 68		if (req || mq->mqrq_prev->req) {
 69			set_current_state(TASK_RUNNING);
 70			mq->issue_fn(mq, req);
 71		} else {
 72			if (kthread_should_stop()) {
 73				set_current_state(TASK_RUNNING);
 74				break;
 75			}
 76			up(&mq->thread_sem);
 77			schedule();
 78			down(&mq->thread_sem);
 79		}
 80
 81		/* Current request becomes previous request and vice versa. */
 82		mq->mqrq_prev->brq.mrq.data = NULL;
 83		mq->mqrq_prev->req = NULL;
 84		tmp = mq->mqrq_prev;
 85		mq->mqrq_prev = mq->mqrq_cur;
 86		mq->mqrq_cur = tmp;
 87	} while (1);
 88	up(&mq->thread_sem);
 89
 90	return 0;
 91}
 92
 93/*
 94 * Generic MMC request handler.  This is called for any queue on a
 95 * particular host.  When the host is not busy, we look for a request
 96 * on any queue on this host, and attempt to issue it.  This may
 97 * not be the queue we were asked to process.
 98 */
 99static void mmc_request_fn(struct request_queue *q)
100{
101	struct mmc_queue *mq = q->queuedata;
102	struct request *req;
103
104	if (!mq) {
105		while ((req = blk_fetch_request(q)) != NULL) {
106			req->cmd_flags |= REQ_QUIET;
107			__blk_end_request_all(req, -EIO);
108		}
109		return;
110	}
111
112	if (!mq->mqrq_cur->req && !mq->mqrq_prev->req)
113		wake_up_process(mq->thread);
114}
115
116static struct scatterlist *mmc_alloc_sg(int sg_len, int *err)
117{
118	struct scatterlist *sg;
119
120	sg = kmalloc(sizeof(struct scatterlist)*sg_len, GFP_KERNEL);
121	if (!sg)
122		*err = -ENOMEM;
123	else {
124		*err = 0;
125		sg_init_table(sg, sg_len);
126	}
127
128	return sg;
129}
130
131static void mmc_queue_setup_discard(struct request_queue *q,
132				    struct mmc_card *card)
133{
134	unsigned max_discard;
135
136	max_discard = mmc_calc_max_discard(card);
137	if (!max_discard)
138		return;
139
140	queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
141	q->limits.max_discard_sectors = max_discard;
142	if (card->erased_byte == 0 && !mmc_can_discard(card))
143		q->limits.discard_zeroes_data = 1;
144	q->limits.discard_granularity = card->pref_erase << 9;
145	/* granularity must not be greater than max. discard */
146	if (card->pref_erase > max_discard)
147		q->limits.discard_granularity = 0;
148	if (mmc_can_secure_erase_trim(card) || mmc_can_sanitize(card))
149		queue_flag_set_unlocked(QUEUE_FLAG_SECDISCARD, q);
150}
151
152/**
153 * mmc_init_queue - initialise a queue structure.
154 * @mq: mmc queue
155 * @card: mmc card to attach this queue
156 * @lock: queue lock
157 * @subname: partition subname
158 *
159 * Initialise a MMC card request queue.
160 */
161int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card,
162		   spinlock_t *lock, const char *subname)
163{
164	struct mmc_host *host = card->host;
165	u64 limit = BLK_BOUNCE_HIGH;
166	int ret;
167	struct mmc_queue_req *mqrq_cur = &mq->mqrq[0];
168	struct mmc_queue_req *mqrq_prev = &mq->mqrq[1];
169
170	if (mmc_dev(host)->dma_mask && *mmc_dev(host)->dma_mask)
171		limit = *mmc_dev(host)->dma_mask;
172
173	mq->card = card;
174	mq->queue = blk_init_queue(mmc_request_fn, lock);
175	if (!mq->queue)
176		return -ENOMEM;
177
178	mq->mqrq_cur = mqrq_cur;
179	mq->mqrq_prev = mqrq_prev;
180	mq->queue->queuedata = mq;
181
182	blk_queue_prep_rq(mq->queue, mmc_prep_request);
183	queue_flag_set_unlocked(QUEUE_FLAG_NONROT, mq->queue);
184	if (mmc_can_erase(card))
185		mmc_queue_setup_discard(mq->queue, card);
186
187#ifdef CONFIG_MMC_BLOCK_BOUNCE
188	if (host->max_segs == 1) {
189		unsigned int bouncesz;
190
191		bouncesz = MMC_QUEUE_BOUNCESZ;
192
193		if (bouncesz > host->max_req_size)
194			bouncesz = host->max_req_size;
195		if (bouncesz > host->max_seg_size)
196			bouncesz = host->max_seg_size;
197		if (bouncesz > (host->max_blk_count * 512))
198			bouncesz = host->max_blk_count * 512;
199
200		if (bouncesz > 512) {
201			mqrq_cur->bounce_buf = kmalloc(bouncesz, GFP_KERNEL);
202			if (!mqrq_cur->bounce_buf) {
203				pr_warning("%s: unable to "
204					"allocate bounce cur buffer\n",
205					mmc_card_name(card));
206			}
207			mqrq_prev->bounce_buf = kmalloc(bouncesz, GFP_KERNEL);
208			if (!mqrq_prev->bounce_buf) {
209				pr_warning("%s: unable to "
210					"allocate bounce prev buffer\n",
211					mmc_card_name(card));
212				kfree(mqrq_cur->bounce_buf);
213				mqrq_cur->bounce_buf = NULL;
214			}
215		}
216
217		if (mqrq_cur->bounce_buf && mqrq_prev->bounce_buf) {
218			blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_ANY);
219			blk_queue_max_hw_sectors(mq->queue, bouncesz / 512);
220			blk_queue_max_segments(mq->queue, bouncesz / 512);
221			blk_queue_max_segment_size(mq->queue, bouncesz);
222
223			mqrq_cur->sg = mmc_alloc_sg(1, &ret);
224			if (ret)
225				goto cleanup_queue;
226
227			mqrq_cur->bounce_sg =
228				mmc_alloc_sg(bouncesz / 512, &ret);
229			if (ret)
230				goto cleanup_queue;
231
232			mqrq_prev->sg = mmc_alloc_sg(1, &ret);
233			if (ret)
234				goto cleanup_queue;
235
236			mqrq_prev->bounce_sg =
237				mmc_alloc_sg(bouncesz / 512, &ret);
238			if (ret)
239				goto cleanup_queue;
240		}
241	}
242#endif
243
244	if (!mqrq_cur->bounce_buf && !mqrq_prev->bounce_buf) {
245		blk_queue_bounce_limit(mq->queue, limit);
246		blk_queue_max_hw_sectors(mq->queue,
247			min(host->max_blk_count, host->max_req_size / 512));
248		blk_queue_max_segments(mq->queue, host->max_segs);
249		blk_queue_max_segment_size(mq->queue, host->max_seg_size);
250
251		mqrq_cur->sg = mmc_alloc_sg(host->max_segs, &ret);
252		if (ret)
253			goto cleanup_queue;
254
255
256		mqrq_prev->sg = mmc_alloc_sg(host->max_segs, &ret);
257		if (ret)
258			goto cleanup_queue;
259	}
260
261	sema_init(&mq->thread_sem, 1);
262
263	mq->thread = kthread_run(mmc_queue_thread, mq, "mmcqd/%d%s",
264		host->index, subname ? subname : "");
265
266	if (IS_ERR(mq->thread)) {
267		ret = PTR_ERR(mq->thread);
268		goto free_bounce_sg;
269	}
270
271	return 0;
272 free_bounce_sg:
273	kfree(mqrq_cur->bounce_sg);
274	mqrq_cur->bounce_sg = NULL;
275	kfree(mqrq_prev->bounce_sg);
276	mqrq_prev->bounce_sg = NULL;
277
278 cleanup_queue:
279	kfree(mqrq_cur->sg);
280	mqrq_cur->sg = NULL;
281	kfree(mqrq_cur->bounce_buf);
282	mqrq_cur->bounce_buf = NULL;
283
284	kfree(mqrq_prev->sg);
285	mqrq_prev->sg = NULL;
286	kfree(mqrq_prev->bounce_buf);
287	mqrq_prev->bounce_buf = NULL;
288
289	blk_cleanup_queue(mq->queue);
290	return ret;
291}
292
293void mmc_cleanup_queue(struct mmc_queue *mq)
294{
295	struct request_queue *q = mq->queue;
296	unsigned long flags;
297	struct mmc_queue_req *mqrq_cur = mq->mqrq_cur;
298	struct mmc_queue_req *mqrq_prev = mq->mqrq_prev;
299
300	/* Make sure the queue isn't suspended, as that will deadlock */
301	mmc_queue_resume(mq);
302
303	/* Then terminate our worker thread */
304	kthread_stop(mq->thread);
305
306	/* Empty the queue */
307	spin_lock_irqsave(q->queue_lock, flags);
308	q->queuedata = NULL;
309	blk_start_queue(q);
310	spin_unlock_irqrestore(q->queue_lock, flags);
311
312	kfree(mqrq_cur->bounce_sg);
313	mqrq_cur->bounce_sg = NULL;
314
315	kfree(mqrq_cur->sg);
316	mqrq_cur->sg = NULL;
317
318	kfree(mqrq_cur->bounce_buf);
319	mqrq_cur->bounce_buf = NULL;
320
321	kfree(mqrq_prev->bounce_sg);
322	mqrq_prev->bounce_sg = NULL;
323
324	kfree(mqrq_prev->sg);
325	mqrq_prev->sg = NULL;
326
327	kfree(mqrq_prev->bounce_buf);
328	mqrq_prev->bounce_buf = NULL;
329
330	mq->card = NULL;
331}
332EXPORT_SYMBOL(mmc_cleanup_queue);
333
334/**
335 * mmc_queue_suspend - suspend a MMC request queue
336 * @mq: MMC queue to suspend
337 *
338 * Stop the block request queue, and wait for our thread to
339 * complete any outstanding requests.  This ensures that we
340 * won't suspend while a request is being processed.
341 */
342void mmc_queue_suspend(struct mmc_queue *mq)
343{
344	struct request_queue *q = mq->queue;
345	unsigned long flags;
346
347	if (!(mq->flags & MMC_QUEUE_SUSPENDED)) {
348		mq->flags |= MMC_QUEUE_SUSPENDED;
349
350		spin_lock_irqsave(q->queue_lock, flags);
351		blk_stop_queue(q);
352		spin_unlock_irqrestore(q->queue_lock, flags);
353
354		down(&mq->thread_sem);
355	}
356}
357
358/**
359 * mmc_queue_resume - resume a previously suspended MMC request queue
360 * @mq: MMC queue to resume
361 */
362void mmc_queue_resume(struct mmc_queue *mq)
363{
364	struct request_queue *q = mq->queue;
365	unsigned long flags;
366
367	if (mq->flags & MMC_QUEUE_SUSPENDED) {
368		mq->flags &= ~MMC_QUEUE_SUSPENDED;
369
370		up(&mq->thread_sem);
371
372		spin_lock_irqsave(q->queue_lock, flags);
373		blk_start_queue(q);
374		spin_unlock_irqrestore(q->queue_lock, flags);
375	}
376}
377
378/*
379 * Prepare the sg list(s) to be handed of to the host driver
380 */
381unsigned int mmc_queue_map_sg(struct mmc_queue *mq, struct mmc_queue_req *mqrq)
382{
383	unsigned int sg_len;
384	size_t buflen;
385	struct scatterlist *sg;
386	int i;
387
388	if (!mqrq->bounce_buf)
389		return blk_rq_map_sg(mq->queue, mqrq->req, mqrq->sg);
390
391	BUG_ON(!mqrq->bounce_sg);
392
393	sg_len = blk_rq_map_sg(mq->queue, mqrq->req, mqrq->bounce_sg);
394
395	mqrq->bounce_sg_len = sg_len;
396
397	buflen = 0;
398	for_each_sg(mqrq->bounce_sg, sg, sg_len, i)
399		buflen += sg->length;
400
401	sg_init_one(mqrq->sg, mqrq->bounce_buf, buflen);
402
403	return 1;
404}
405
406/*
407 * If writing, bounce the data to the buffer before the request
408 * is sent to the host driver
409 */
410void mmc_queue_bounce_pre(struct mmc_queue_req *mqrq)
411{
412	if (!mqrq->bounce_buf)
413		return;
414
415	if (rq_data_dir(mqrq->req) != WRITE)
416		return;
417
418	sg_copy_to_buffer(mqrq->bounce_sg, mqrq->bounce_sg_len,
419		mqrq->bounce_buf, mqrq->sg[0].length);
420}
421
422/*
423 * If reading, bounce the data from the buffer after the request
424 * has been handled by the host driver
425 */
426void mmc_queue_bounce_post(struct mmc_queue_req *mqrq)
427{
428	if (!mqrq->bounce_buf)
429		return;
430
431	if (rq_data_dir(mqrq->req) != READ)
432		return;
433
434	sg_copy_from_buffer(mqrq->bounce_sg, mqrq->bounce_sg_len,
435		mqrq->bounce_buf, mqrq->sg[0].length);
436}