sd_queue.c

linux 2.6下的sd卡驱动

#include <linux/module.h>
#include <linux/blkdev.h>

#include "sd.h"

/**
 * 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;
}