- 根目录:
- drivers
- mmc
- card
- queue.c
/*
* 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/slab.h>
#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/freezer.h>
#include <linux/kthread.h>
#include <linux/scatterlist.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)
{
struct mmc_queue *mq = q->queuedata;
/*
* We only like normal block requests and discards.
*/
if (req->cmd_type != REQ_TYPE_FS && !(req->cmd_flags & REQ_DISCARD)) {
blk_dump_rq_flags(req, "MMC bad request");
return BLKPREP_KILL;
}
if (mq && mmc_card_removed(mq->card))
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;
struct mmc_queue_req *tmp;
spin_lock_irq(q->queue_lock);
set_current_state(TASK_INTERRUPTIBLE);
req = blk_fetch_request(q);
mq->mqrq_cur->req = req;
spin_unlock_irq(q->queue_lock);
if (req || mq->mqrq_prev->req) {
set_current_state(TASK_RUNNING);
mq->issue_fn(mq, req);
} else {
if (kthread_should_stop()) {
set_current_state(TASK_RUNNING);
break;
}
up(&mq->thread_sem);
schedule();
down(&mq->thread_sem);
}
/* Current request becomes previous request and vice versa. */
mq->mqrq_prev->brq.mrq.data = NULL;
mq->mqrq_prev->req = NULL;
tmp = mq->mqrq_prev;
mq->mqrq_prev = mq->mqrq_cur;
mq->mqrq_cur = tmp;
} 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;
if (!mq) {
while ((req = blk_fetch_request(q)) != NULL) {
req->cmd_flags |= REQ_QUIET;
__blk_end_request_all(req, -EIO);
}
return;
}
if (!mq->mqrq_cur->req && !mq->mqrq_prev->req)
wake_up_process(mq->thread);
}
static struct scatterlist *mmc_alloc_sg(int sg_len, int *err)
{
struct scatterlist *sg;
sg = kmalloc(sizeof(struct scatterlist)*sg_len, GFP_KERNEL);
if (!sg)
*err = -ENOMEM;
else {
*err = 0;
sg_init_table(sg, sg_len);
}
return sg;
}
static void mmc_queue_setup_discard(struct request_queue *q,
struct mmc_card *card)
{
unsigned max_discard;
max_discard = mmc_calc_max_discard(card);
if (!max_discard)
return;
queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
q->limits.max_discard_sectors = max_discard;
if (card->erased_byte == 0 && !mmc_can_discard(card))
q->limits.discard_zeroes_data = 1;
q->limits.discard_granularity = card->pref_erase << 9;
/* granularity must not be greater than max. discard */
if (card->pref_erase > max_discard)
q->limits.discard_granularity = 0;
if (mmc_can_secure_erase_trim(card) || mmc_can_sanitize(card))
queue_flag_set_unlocked(QUEUE_FLAG_SECDISCARD, q);
}
/**
* mmc_init_queue - initialise a queue structure.
* @mq: mmc queue
* @card: mmc card to attach this queue
* @lock: queue lock
* @subname: partition subname
*
* Initialise a MMC card request queue.
*/
int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card,
spinlock_t *lock, const char *subname)
{
struct mmc_host *host = card->host;
u64 limit = BLK_BOUNCE_HIGH;
int ret;
struct mmc_queue_req *mqrq_cur = &mq->mqrq[0];
struct mmc_queue_req *mqrq_prev = &mq->mqrq[1];
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;
memset(&mq->mqrq_cur, 0, sizeof(mq->mqrq_cur));
memset(&mq->mqrq_prev, 0, sizeof(mq->mqrq_prev));
mq->mqrq_cur = mqrq_cur;
mq->mqrq_prev = mqrq_prev;
mq->queue->queuedata = mq;
blk_queue_prep_rq(mq->queue, mmc_prep_request);
queue_flag_set_unlocked(QUEUE_FLAG_NONROT, mq->queue);
if (mmc_can_erase(card))
mmc_queue_setup_discard(mq->queue, card);
#ifdef CONFIG_MMC_BLOCK_BOUNCE
if (host->max_segs == 1) {
unsigned int bouncesz;
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;
if (bouncesz > (host->max_blk_count * 512))
bouncesz = host->max_blk_count * 512;
if (bouncesz > 512) {
mqrq_cur->bounce_buf = kmalloc(bouncesz, GFP_KERNEL);
if (!mqrq_cur->bounce_buf) {
pr_warning("%s: unable to "
"allocate bounce cur buffer\n",
mmc_card_name(card));
}
mqrq_prev->bounce_buf = kmalloc(bouncesz, GFP_KERNEL);
if (!mqrq_prev->bounce_buf) {
pr_warning("%s: unable to "
"allocate bounce prev buffer\n",
mmc_card_name(card));
kfree(mqrq_cur->bounce_buf);
mqrq_cur->bounce_buf = NULL;
}
}
if (mqrq_cur->bounce_buf && mqrq_prev->bounce_buf) {
blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_ANY);
blk_queue_max_hw_sectors(mq->queue, bouncesz / 512);
blk_queue_max_segments(mq->queue, bouncesz / 512);
blk_queue_max_segment_size(mq->queue, bouncesz);
mqrq_cur->sg = mmc_alloc_sg(1, &ret);
if (ret)
goto cleanup_queue;
mqrq_cur->bounce_sg =
mmc_alloc_sg(bouncesz / 512, &ret);
if (ret)
goto cleanup_queue;
mqrq_prev->sg = mmc_alloc_sg(1, &ret);
if (ret)
goto cleanup_queue;
mqrq_prev->bounce_sg =
mmc_alloc_sg(bouncesz / 512, &ret);
if (ret)
goto cleanup_queue;
}
}
#endif
if (!mqrq_cur->bounce_buf && !mqrq_prev->bounce_buf) {
blk_queue_bounce_limit(mq->queue, limit);
blk_queue_max_hw_sectors(mq->queue,
min(host->max_blk_count, host->max_req_size / 512));
blk_queue_max_segments(mq->queue, host->max_segs);
blk_queue_max_segment_size(mq->queue, host->max_seg_size);
mqrq_cur->sg = mmc_alloc_sg(host->max_segs, &ret);
if (ret)
goto cleanup_queue;
mqrq_prev->sg = mmc_alloc_sg(host->max_segs, &ret);
if (ret)
goto cleanup_queue;
}
sema_init(&mq->thread_sem, 1);
mq->thread = kthread_run(mmc_queue_thread, mq, "mmcqd/%d%s",
host->index, subname ? subname : "");
if (IS_ERR(mq->thread)) {
ret = PTR_ERR(mq->thread);
goto free_bounce_sg;
}
return 0;
free_bounce_sg:
kfree(mqrq_cur->bounce_sg);
mqrq_cur->bounce_sg = NULL;
kfree(mqrq_prev->bounce_sg);
mqrq_prev->bounce_sg = NULL;
cleanup_queue:
kfree(mqrq_cur->sg);
mqrq_cur->sg = NULL;
kfree(mqrq_cur->bounce_buf);
mqrq_cur->bounce_buf = NULL;
kfree(mqrq_prev->sg);
mqrq_prev->sg = NULL;
kfree(mqrq_prev->bounce_buf);
mqrq_prev->bounce_buf = NULL;
blk_cleanup_queue(mq->queue);
return ret;
}
void mmc_cleanup_queue(struct mmc_queue *mq)
{
struct request_queue *q = mq->queue;
unsigned long flags;
struct mmc_queue_req *mqrq_cur = mq->mqrq_cur;
struct mmc_queue_req *mqrq_prev = mq->mqrq_prev;
/* Make sure the queue isn't suspended, as that will deadlock */
mmc_queue_resume(mq);
/* Then terminate our worker thread */
kthread_stop(mq->thread);
/* Empty the queue */
spin_lock_irqsave(q->queue_lock, flags);
q->queuedata = NULL;
blk_start_queue(q);
spin_unlock_irqrestore(q->queue_lock, flags);
kfree(mqrq_cur->bounce_sg);
mqrq_cur->bounce_sg = NULL;
kfree(mqrq_cur->sg);
mqrq_cur->sg = NULL;
kfree(mqrq_cur->bounce_buf);
mqrq_cur->bounce_buf = NULL;
kfree(mqrq_prev->bounce_sg);
mqrq_prev->bounce_sg = NULL;
kfree(mqrq_prev->sg);
mqrq_prev->sg = NULL;
kfree(mqrq_prev->bounce_buf);
mqrq_prev->bounce_buf = NULL;
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);
}
}
/*
* Prepare the sg list(s) to be handed of to the host driver
*/
unsigned int mmc_queue_map_sg(struct mmc_queue *mq, struct mmc_queue_req *mqrq)
{
unsigned int sg_len;
size_t buflen;
struct scatterlist *sg;
int i;
if (!mqrq->bounce_buf)
return blk_rq_map_sg(mq->queue, mqrq->req, mqrq->sg);
BUG_ON(!mqrq->bounce_sg);
sg_len = blk_rq_map_sg(mq->queue, mqrq->req, mqrq->bounce_sg);
mqrq->bounce_sg_len = sg_len;
buflen = 0;
for_each_sg(mqrq->bounce_sg, sg, sg_len, i)
buflen += sg->length;
sg_init_one(mqrq->sg, mqrq->bounce_buf, buflen);
return 1;
}
/*
* If writing, bounce the data to the buffer before the request
* is sent to the host driver
*/
void mmc_queue_bounce_pre(struct mmc_queue_req *mqrq)
{
if (!mqrq->bounce_buf)
return;
if (rq_data_dir(mqrq->req) != WRITE)
return;
sg_copy_to_buffer(mqrq->bounce_sg, mqrq->bounce_sg_len,
mqrq->bounce_buf, mqrq->sg[0].length);
}
/*
* If reading, bounce the data from the buffer after the request
* has been handled by the host driver
*/
void mmc_queue_bounce_post(struct mmc_queue_req *mqrq)
{
if (!mqrq->bounce_buf)
return;
if (rq_data_dir(mqrq->req) != READ)
return;
sg_copy_from_buffer(mqrq->bounce_sg, mqrq->bounce_sg_len,
mqrq->bounce_buf, mqrq->sg[0].length);
}