/* * linux/drivers/mmc/mmc_queue.c * * Copyright (C) 2003 Russell King, All Rights Reserved. * * 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/mmc/card.h> #include <linux/mmc/host.h> #include "mmc_queue.h" #define MMC_QUEUE_EXIT (1 << 0) #define MMC_QUEUE_SUSPENDED (1 << 1) /* * 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 (req->flags & REQ_SPECIAL) { /* * Special commands already have the command * blocks already setup in req->special. */ BUG_ON(!req->special); ret = BLKPREP_OK; } else if (req->flags & (REQ_CMD | REQ_BLOCK_PC)) { /* * 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->flags |= REQ_DONTPREP; return ret; } static int mmc_queue_thread(void *d) { struct mmc_queue *mq = d; struct request_queue *q = mq->queue; DECLARE_WAITQUEUE(wait, current); /* * 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; daemonize("mmcqd"); complete(&mq->thread_complete); down(&mq->thread_sem); add_wait_queue(&mq->thread_wq, &wait); do { struct request *req = NULL; spin_lock_irq(q->queue_lock); set_current_state(TASK_INTERRUPTIBLE); if (!blk_queue_plugged(q)) mq->req = req = elv_next_request(q); spin_unlock_irq(q->queue_lock); if (!req) { if (mq->flags & MMC_QUEUE_EXIT) break; up(&mq->thread_sem); schedule(); down(&mq->thread_sem); continue; } set_current_state(TASK_RUNNING); mq->issue_fn(mq, req); } while (1); remove_wait_queue(&mq->thread_wq, &wait); up(&mq->thread_sem); complete_and_exit(&mq->thread_complete, 0); 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; if (!mq->req) wake_up(&mq->thread_wq); } /** * 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 (host->dev->dma_mask && *host->dev->dma_mask) limit = *host->dev->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_sectors); 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; } init_completion(&mq->thread_complete); init_waitqueue_head(&mq->thread_wq); init_MUTEX(&mq->thread_sem); ret = kernel_thread(mmc_queue_thread, mq, CLONE_KERNEL); if (ret >= 0) { wait_for_completion(&mq->thread_complete); init_completion(&mq->thread_complete); ret = 0; goto out; } cleanup: kfree(mq->sg); mq->sg = NULL; blk_cleanup_queue(mq->queue); out: return ret; } EXPORT_SYMBOL(mmc_init_queue); void mmc_cleanup_queue(struct mmc_queue *mq) { mq->flags |= MMC_QUEUE_EXIT; wake_up(&mq->thread_wq); wait_for_completion(&mq->thread_complete); 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); } } EXPORT_SYMBOL(mmc_queue_suspend); /** * 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); } } EXPORT_SYMBOL(mmc_queue_resume);