--- /dev/null
+/*
+ * 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(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;
+
+ 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) {
+ blk_cleanup_queue(mq->queue);
+ } else {
+ wait_for_completion(&mq->thread_complete);
+ init_completion(&mq->thread_complete);
+ ret = 0;
+ }
+
+ 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);
+ 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);
git://git.onelab.eu / linux-2.6.git / blobdiff