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