/*
* 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/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)
{
/*
* 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 = __blk_end_request(req, -EIO,
blk_rq_cur_bytes(req));
} 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;
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);
blk_queue_ordered(mq->queue, QUEUE_ORDERED_DRAIN, NULL);
#ifdef CONFIG_MMC_BLOCK_BOUNCE
if (host->max_hw_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) {
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));
}
}
if (mq->bounce_buf) {
blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_ANY);
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 cleanup_queue;
}
sg_init_table(mq->sg, 1);
mq->bounce_sg = kmalloc(sizeof(struct scatterlist) *
bouncesz / 512, GFP_KERNEL);
if (!mq->bounce_sg) {
ret = -ENOMEM;
goto cleanup_queue;
}
sg_init_table(mq->bounce_sg, bouncesz / 512);
}
}
#endif
if (!mq->bounce_buf) {
blk_queue_bounce_limit(mq->queue, limit);
blk_queue_max_sectors(mq->queue,
min(host->max_blk_count, 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;
}
sg_init_table(mq->sg, host->max_phys_segs);
}
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;
cleanup_queue:
if (mq->sg)
kfree(mq->sg);
mq->sg = NULL;
if (mq->bounce_buf)
kfree(mq->bounce_buf);
mq->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;
/* 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);
}
}
/*
* Prepare the sg list(s) to be handed of to the host driver
*/
unsigned int mmc_queue_map_sg(struct mmc_queue *mq)
{
unsigned int sg_len;
size_t buflen;
struct scatterlist *sg;
int i;
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;
buflen = 0;
for_each_sg(mq->bounce_sg, sg, sg_len, i)
buflen += sg->length;
sg_init_one(mq->sg, mq->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 *mq)
{
unsigned long flags;
if (!mq->bounce_buf)
return;
if (rq_data_dir(mq->req) != WRITE)
return;
local_irq_save(flags);
sg_copy_to_buffer(mq->bounce_sg, mq->bounce_sg_len,
mq->bounce_buf, mq->sg[0].length);
local_irq_restore(flags);
}
/*
* 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 *mq)
{
unsigned long flags;
if (!mq->bounce_buf)
return;
if (rq_data_dir(mq->req) != READ)
return;
local_irq_save(flags);
sg_copy_from_buffer(mq->bounce_sg, mq->bounce_sg_len,
mq->bounce_buf, mq->sg[0].length);
local_irq_restore(flags);
}
