diff options
Diffstat (limited to 'drivers/mmc/card/queue.c')
| -rw-r--r-- | drivers/mmc/card/queue.c | 252 |
1 files changed, 252 insertions, 0 deletions
diff --git a/drivers/mmc/card/queue.c b/drivers/mmc/card/queue.c new file mode 100644 index 00000000000..2e77963db33 --- /dev/null +++ b/drivers/mmc/card/queue.c @@ -0,0 +1,252 @@ +/* + * linux/drivers/mmc/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/kthread.h> + +#include <linux/mmc/card.h> +#include <linux/mmc/host.h> +#include "queue.h" + +#define MMC_QUEUE_SUSPENDED (1 << 0) + +/* + * Prepare a MMC request. Essentially, this means passing the + * preparation off to the media driver. The media driver will + * create a mmc_io_request in req->special. + */ +static int mmc_prep_request(struct request_queue *q, struct request *req) +{ + struct mmc_queue *mq = q->queuedata; + int ret = BLKPREP_KILL; + + if (blk_special_request(req)) { + /* + * Special commands already have the command + * blocks already setup in req->special. + */ + BUG_ON(!req->special); + + ret = BLKPREP_OK; + } else if (blk_fs_request(req) || blk_pc_request(req)) { + /* + * Block I/O requests need translating according + * to the protocol. + */ + ret = mq->prep_fn(mq, req); + } else { + /* + * Everything else is invalid. + */ + blk_dump_rq_flags(req, "MMC bad request"); + } + + if (ret == BLKPREP_OK) + req->cmd_flags |= REQ_DONTPREP; + + return ret; +} + +static int mmc_queue_thread(void *d) +{ + struct mmc_queue *mq = d; + struct request_queue *q = mq->queue; + + /* + * Set iothread to ensure that we aren't put to sleep by + * the process freezing. We handle suspension ourselves. + */ + current->flags |= PF_MEMALLOC|PF_NOFREEZE; + + 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(request_queue_t *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 = end_that_request_chunk(req, 0, + req->current_nr_sectors << 9); + } 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; + + blk_queue_prep_rq(mq->queue, mmc_prep_request); + blk_queue_bounce_limit(mq->queue, limit); + blk_queue_max_sectors(mq->queue, 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->queue->queuedata = mq; + mq->req = NULL; + + mq->sg = kmalloc(sizeof(struct scatterlist) * host->max_phys_segs, + GFP_KERNEL); + if (!mq->sg) { + ret = -ENOMEM; + goto cleanup_queue; + } + + 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_sg; + } + + return 0; + + free_sg: + kfree(mq->sg); + mq->sg = NULL; + cleanup_queue: + blk_cleanup_queue(mq->queue); + return ret; +} + +void mmc_cleanup_queue(struct mmc_queue *mq) +{ + request_queue_t *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); + + kfree(mq->sg); + mq->sg = 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) +{ + request_queue_t *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) +{ + request_queue_t *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); + } +} + |