drivers/mmc/mmc_block.c - kernel/msm-4.9 - Gitiles

 /*
  * Block driver for media (i.e., flash cards)
  *
  * Copyright 2002 Hewlett-Packard Company
  *
  * Use consistent with the GNU GPL is permitted,
  * provided that this copyright notice is
  * preserved in its entirety in all copies and derived works.
  *
  * HEWLETT-PACKARD COMPANY MAKES NO WARRANTIES, EXPRESSED OR IMPLIED,
  * AS TO THE USEFULNESS OR CORRECTNESS OF THIS CODE OR ITS
  * FITNESS FOR ANY PARTICULAR PURPOSE.
  *
  * Many thanks to Alessandro Rubini and Jonathan Corbet!
  *
  * Author:  Andrew Christian
  *          28 May 2002
  */
 #include <linux/moduleparam.h>
 #include <linux/module.h>
 #include <linux/init.h>

 #include <linux/sched.h>
 #include <linux/kernel.h>
 #include <linux/fs.h>
 #include <linux/errno.h>
 #include <linux/hdreg.h>
 #include <linux/kdev_t.h>
 #include <linux/blkdev.h>
 #include <linux/devfs_fs_kernel.h>

 #include <linux/mmc/card.h>
 #include <linux/mmc/protocol.h>

 #include <asm/system.h>
 #include <asm/uaccess.h>

 #include "mmc_queue.h"

 /*
  * max 8 partitions per card
  */
 #define MMC_SHIFT	3

 static int major;

 /*
  * There is one mmc_blk_data per slot.
  */
 struct mmc_blk_data {
 	spinlock_t	lock;
 	struct gendisk	*disk;
 	struct mmc_queue queue;

 	unsigned int	usage;
 	unsigned int	block_bits;
 };

 static DECLARE_MUTEX(open_lock);

 static struct mmc_blk_data *mmc_blk_get(struct gendisk *disk)
 {
 	struct mmc_blk_data *md;

 	down(&open_lock);
 	md = disk->private_data;
 	if (md && md->usage == 0)
 		md = NULL;
 	if (md)
 		md->usage++;
 	up(&open_lock);

 	return md;
 }

 static void mmc_blk_put(struct mmc_blk_data *md)
 {
 	down(&open_lock);
 	md->usage--;
 	if (md->usage == 0) {
 		put_disk(md->disk);
 		mmc_cleanup_queue(&md->queue);
 		kfree(md);
 	}
 	up(&open_lock);
 }

 static inline int mmc_blk_readonly(struct mmc_card *card)
 {
 	return mmc_card_readonly(card) ||
 	       !(card->csd.cmdclass & CCC_BLOCK_WRITE);
 }

 static int mmc_blk_open(struct inode *inode, struct file *filp)
 {
 	struct mmc_blk_data *md;
 	int ret = -ENXIO;

 	md = mmc_blk_get(inode->i_bdev->bd_disk);
 	if (md) {
 		if (md->usage == 2)
 			check_disk_change(inode->i_bdev);
 		ret = 0;

 		if ((filp->f_mode & FMODE_WRITE) &&
 			mmc_blk_readonly(md->queue.card))
 			ret = -EROFS;
 	}

 	return ret;
 }

 static int mmc_blk_release(struct inode *inode, struct file *filp)
 {
 	struct mmc_blk_data *md = inode->i_bdev->bd_disk->private_data;

 	mmc_blk_put(md);
 	return 0;
 }

 static int
 mmc_blk_ioctl(struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg)
 {
 	struct block_device *bdev = inode->i_bdev;

 	if (cmd == HDIO_GETGEO) {
 		struct hd_geometry geo;

 		memset(&geo, 0, sizeof(struct hd_geometry));

 		geo.cylinders	= get_capacity(bdev->bd_disk) / (4 * 16);
 		geo.heads	= 4;
 		geo.sectors	= 16;
 		geo.start	= get_start_sect(bdev);

 		return copy_to_user((void __user *)arg, &geo, sizeof(geo))
 			? -EFAULT : 0;
 	}

 	return -ENOTTY;
 }

 static struct block_device_operations mmc_bdops = {
 	.open			= mmc_blk_open,
 	.release		= mmc_blk_release,
 	.ioctl			= mmc_blk_ioctl,
 	.owner			= THIS_MODULE,
 };

 struct mmc_blk_request {
 	struct mmc_request	mrq;
 	struct mmc_command	cmd;
 	struct mmc_command	stop;
 	struct mmc_data		data;
 };

 static int mmc_blk_prep_rq(struct mmc_queue *mq, struct request *req)
 {
 	struct mmc_blk_data *md = mq->data;
 	int stat = BLKPREP_OK;

 	/*
 	 * If we have no device, we haven't finished initialising.
 	 */
 	if (!md || !mq->card) {
 		printk(KERN_ERR "%s: killing request - no device/host\n",
 		       req->rq_disk->disk_name);
 		stat = BLKPREP_KILL;
 	}

 	return stat;
 }

 static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
 {
 	struct mmc_blk_data *md = mq->data;
 	struct mmc_card *card = md->queue.card;
 	int ret;

 	if (mmc_card_claim_host(card))
 		goto cmd_err;

 	do {
 		struct mmc_blk_request brq;
 		struct mmc_command cmd;

 		memset(&brq, 0, sizeof(struct mmc_blk_request));
 		brq.mrq.cmd = &brq.cmd;
 		brq.mrq.data = &brq.data;

 		brq.cmd.arg = req->sector << 9;
 		brq.cmd.flags = MMC_RSP_R1;
 		brq.data.timeout_ns = card->csd.tacc_ns * 10;
 		brq.data.timeout_clks = card->csd.tacc_clks * 10;
 		brq.data.blksz_bits = md->block_bits;
 		brq.data.blocks = req->nr_sectors >> (md->block_bits - 9);
 		brq.stop.opcode = MMC_STOP_TRANSMISSION;
 		brq.stop.arg = 0;
 		brq.stop.flags = MMC_RSP_R1B;

 		if (rq_data_dir(req) == READ) {
 			brq.cmd.opcode = brq.data.blocks > 1 ? MMC_READ_MULTIPLE_BLOCK : MMC_READ_SINGLE_BLOCK;
 			brq.data.flags |= MMC_DATA_READ;
 		} else {
 			brq.cmd.opcode = MMC_WRITE_BLOCK;
 			brq.data.flags |= MMC_DATA_WRITE;
 			brq.data.blocks = 1;
 		}
 		brq.mrq.stop = brq.data.blocks > 1 ? &brq.stop : NULL;

 		brq.data.sg = mq->sg;
 		brq.data.sg_len = blk_rq_map_sg(req->q, req, brq.data.sg);

 		mmc_wait_for_req(card->host, &brq.mrq);
 		if (brq.cmd.error) {
 			printk(KERN_ERR "%s: error %d sending read/write command\n",
 			       req->rq_disk->disk_name, brq.cmd.error);
 			goto cmd_err;
 		}

 		if (brq.data.error) {
 			printk(KERN_ERR "%s: error %d transferring data\n",
 			       req->rq_disk->disk_name, brq.data.error);
 			goto cmd_err;
 		}

 		if (brq.stop.error) {
 			printk(KERN_ERR "%s: error %d sending stop command\n",
 			       req->rq_disk->disk_name, brq.stop.error);
 			goto cmd_err;
 		}

 		do {
 			int err;

 			cmd.opcode = MMC_SEND_STATUS;
 			cmd.arg = card->rca << 16;
 			cmd.flags = MMC_RSP_R1;
 			err = mmc_wait_for_cmd(card->host, &cmd, 5);
 			if (err) {
 				printk(KERN_ERR "%s: error %d requesting status\n",
 				       req->rq_disk->disk_name, err);
 				goto cmd_err;
 			}
 		} while (!(cmd.resp[0] & R1_READY_FOR_DATA));

 #if 0
 		if (cmd.resp[0] & ~0x00000900)
 			printk(KERN_ERR "%s: status = %08x\n",
 			       req->rq_disk->disk_name, cmd.resp[0]);
 		if (mmc_decode_status(cmd.resp))
 			goto cmd_err;
 #endif

 		/*
 		 * A block was successfully transferred.
 		 */
 		spin_lock_irq(&md->lock);
 		ret = end_that_request_chunk(req, 1, brq.data.bytes_xfered);
 		if (!ret) {
 			/*
 			 * The whole request completed successfully.
 			 */
 			add_disk_randomness(req->rq_disk);
 			blkdev_dequeue_request(req);
 			end_that_request_last(req);
 		}
 		spin_unlock_irq(&md->lock);
 	} while (ret);

 	mmc_card_release_host(card);

 	return 1;

  cmd_err:
 	mmc_card_release_host(card);

 	/*
 	 * This is a little draconian, but until we get proper
 	 * error handling sorted out here, its the best we can
 	 * do - especially as some hosts have no idea how much
 	 * data was transferred before the error occurred.
 	 */
 	spin_lock_irq(&md->lock);
 	do {
 		ret = end_that_request_chunk(req, 0,
 				req->current_nr_sectors << 9);
 	} while (ret);

 	add_disk_randomness(req->rq_disk);
 	blkdev_dequeue_request(req);
 	end_that_request_last(req);
 	spin_unlock_irq(&md->lock);

 	return 0;
 }

 #define MMC_NUM_MINORS	(256 >> MMC_SHIFT)

 static unsigned long dev_use[MMC_NUM_MINORS/(8*sizeof(unsigned long))];

 static struct mmc_blk_data *mmc_blk_alloc(struct mmc_card *card)
 {
 	struct mmc_blk_data *md;
 	int devidx, ret;

 	devidx = find_first_zero_bit(dev_use, MMC_NUM_MINORS);
 	if (devidx >= MMC_NUM_MINORS)
 		return ERR_PTR(-ENOSPC);
 	__set_bit(devidx, dev_use);

 	md = kmalloc(sizeof(struct mmc_blk_data), GFP_KERNEL);
 	if (md) {
 		memset(md, 0, sizeof(struct mmc_blk_data));

 		md->disk = alloc_disk(1 << MMC_SHIFT);
 		if (md->disk == NULL) {
 			kfree(md);
 			md = ERR_PTR(-ENOMEM);
 			goto out;
 		}

 		spin_lock_init(&md->lock);
 		md->usage = 1;

 		ret = mmc_init_queue(&md->queue, card, &md->lock);
 		if (ret) {
 			put_disk(md->disk);
 			kfree(md);
 			md = ERR_PTR(ret);
 			goto out;
 		}
 		md->queue.prep_fn = mmc_blk_prep_rq;
 		md->queue.issue_fn = mmc_blk_issue_rq;
 		md->queue.data = md;

 		md->disk->major	= major;
 		md->disk->first_minor = devidx << MMC_SHIFT;
 		md->disk->fops = &mmc_bdops;
 		md->disk->private_data = md;
 		md->disk->queue = md->queue.queue;
 		md->disk->driverfs_dev = &card->dev;

 		/*
 		 * As discussed on lkml, GENHD_FL_REMOVABLE should:
 		 *
 		 * - be set for removable media with permanent block devices
 		 * - be unset for removable block devices with permanent media
 		 *
 		 * Since MMC block devices clearly fall under the second
 		 * case, we do not set GENHD_FL_REMOVABLE.  Userspace
 		 * should use the block device creation/destruction hotplug
 		 * messages to tell when the card is present.
 		 */

 		sprintf(md->disk->disk_name, "mmcblk%d", devidx);
 		sprintf(md->disk->devfs_name, "mmc/blk%d", devidx);

 		md->block_bits = card->csd.read_blkbits;

 		blk_queue_hardsect_size(md->queue.queue, 1 << md->block_bits);
 		set_capacity(md->disk, card->csd.capacity);
 	}
  out:
 	return md;
 }

 static int
 mmc_blk_set_blksize(struct mmc_blk_data *md, struct mmc_card *card)
 {
 	struct mmc_command cmd;
 	int err;

 	mmc_card_claim_host(card);
 	cmd.opcode = MMC_SET_BLOCKLEN;
 	cmd.arg = 1 << card->csd.read_blkbits;
 	cmd.flags = MMC_RSP_R1;
 	err = mmc_wait_for_cmd(card->host, &cmd, 5);
 	mmc_card_release_host(card);

 	if (err) {
 		printk(KERN_ERR "%s: unable to set block size to %d: %d\n",
 			md->disk->disk_name, cmd.arg, err);
 		return -EINVAL;
 	}

 	return 0;
 }

 static int mmc_blk_probe(struct mmc_card *card)
 {
 	struct mmc_blk_data *md;
 	int err;

 	/*
 	 * Check that the card supports the command class(es) we need.
 	 */
 	if (!(card->csd.cmdclass & CCC_BLOCK_READ))
 		return -ENODEV;

 	if (card->csd.read_blkbits < 9) {
 		printk(KERN_WARNING "%s: read blocksize too small (%u)\n",
 			mmc_card_id(card), 1 << card->csd.read_blkbits);
 		return -ENODEV;
 	}

 	md = mmc_blk_alloc(card);
 	if (IS_ERR(md))
 		return PTR_ERR(md);

 	err = mmc_blk_set_blksize(md, card);
 	if (err)
 		goto out;

 	printk(KERN_INFO "%s: %s %s %dKiB %s\n",
 		md->disk->disk_name, mmc_card_id(card), mmc_card_name(card),
 		(card->csd.capacity << card->csd.read_blkbits) / 1024,
 		mmc_blk_readonly(card)?"(ro)":"");

 	mmc_set_drvdata(card, md);
 	add_disk(md->disk);
 	return 0;

  out:
 	mmc_blk_put(md);

 	return err;
 }

 static void mmc_blk_remove(struct mmc_card *card)
 {
 	struct mmc_blk_data *md = mmc_get_drvdata(card);

 	if (md) {
 		int devidx;

 		del_gendisk(md->disk);

 		/*
 		 * I think this is needed.
 		 */
 		md->disk->queue = NULL;

 		devidx = md->disk->first_minor >> MMC_SHIFT;
 		__clear_bit(devidx, dev_use);

 		mmc_blk_put(md);
 	}
 	mmc_set_drvdata(card, NULL);
 }

 #ifdef CONFIG_PM
 static int mmc_blk_suspend(struct mmc_card *card, pm_message_t state)
 {
 	struct mmc_blk_data *md = mmc_get_drvdata(card);

 	if (md) {
 		mmc_queue_suspend(&md->queue);
 	}
 	return 0;
 }

 static int mmc_blk_resume(struct mmc_card *card)
 {
 	struct mmc_blk_data *md = mmc_get_drvdata(card);

 	if (md) {
 		mmc_blk_set_blksize(md, card);
 		mmc_queue_resume(&md->queue);
 	}
 	return 0;
 }
 #else
 #define	mmc_blk_suspend	NULL
 #define mmc_blk_resume	NULL
 #endif

 static struct mmc_driver mmc_driver = {
 	.drv		= {
 		.name	= "mmcblk",
 	},
 	.probe		= mmc_blk_probe,
 	.remove		= mmc_blk_remove,
 	.suspend	= mmc_blk_suspend,
 	.resume		= mmc_blk_resume,
 };

 static int __init mmc_blk_init(void)
 {
 	int res = -ENOMEM;

 	res = register_blkdev(major, "mmc");
 	if (res < 0) {
 		printk(KERN_WARNING "Unable to get major %d for MMC media: %d\n",
 		       major, res);
 		goto out;
 	}
 	if (major == 0)
 		major = res;

 	devfs_mk_dir("mmc");
 	return mmc_register_driver(&mmc_driver);

  out:
 	return res;
 }

 static void __exit mmc_blk_exit(void)
 {
 	mmc_unregister_driver(&mmc_driver);
 	devfs_remove("mmc");
 	unregister_blkdev(major, "mmc");
 }

 module_init(mmc_blk_init);
 module_exit(mmc_blk_exit);

 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("Multimedia Card (MMC) block device driver");

 module_param(major, int, 0444);
 MODULE_PARM_DESC(major, "specify the major device number for MMC block driver");
	/*
	* Block driver for media (i.e., flash cards)
	*
	* Copyright 2002 Hewlett-Packard Company
	*
	* Use consistent with the GNU GPL is permitted,
	* provided that this copyright notice is
	* preserved in its entirety in all copies and derived works.
	*
	* HEWLETT-PACKARD COMPANY MAKES NO WARRANTIES, EXPRESSED OR IMPLIED,
	* AS TO THE USEFULNESS OR CORRECTNESS OF THIS CODE OR ITS
	* FITNESS FOR ANY PARTICULAR PURPOSE.
	*
	* Many thanks to Alessandro Rubini and Jonathan Corbet!
	*
	* Author: Andrew Christian
	* 28 May 2002
	*/
	#include <linux/moduleparam.h>
	#include <linux/module.h>
	#include <linux/init.h>

	#include <linux/sched.h>
	#include <linux/kernel.h>
	#include <linux/fs.h>
	#include <linux/errno.h>
	#include <linux/hdreg.h>
	#include <linux/kdev_t.h>
	#include <linux/blkdev.h>
	#include <linux/devfs_fs_kernel.h>

	#include <linux/mmc/card.h>
	#include <linux/mmc/protocol.h>

	#include <asm/system.h>
	#include <asm/uaccess.h>

	#include "mmc_queue.h"

	/*
	* max 8 partitions per card
	*/
	#define MMC_SHIFT 3

	static int major;

	/*
	* There is one mmc_blk_data per slot.
	*/
	struct mmc_blk_data {
	spinlock_t lock;
	struct gendisk *disk;
	struct mmc_queue queue;

	unsigned int usage;
	unsigned int block_bits;
	};

	static DECLARE_MUTEX(open_lock);

	static struct mmc_blk_data mmc_blk_get(struct gendisk disk)
	{
	struct mmc_blk_data *md;

	down(&open_lock);
	md = disk->private_data;
	if (md && md->usage == 0)
	md = NULL;
	if (md)
	md->usage++;
	up(&open_lock);

	return md;
	}

	static void mmc_blk_put(struct mmc_blk_data *md)
	{
	down(&open_lock);
	md->usage--;
	if (md->usage == 0) {
	put_disk(md->disk);
	mmc_cleanup_queue(&md->queue);
	kfree(md);
	}
	up(&open_lock);
	}

	static inline int mmc_blk_readonly(struct mmc_card *card)
	{
	return mmc_card_readonly(card) \|\|
	!(card->csd.cmdclass & CCC_BLOCK_WRITE);
	}

	static int mmc_blk_open(struct inode inode, struct file filp)
	{
	struct mmc_blk_data *md;
	int ret = -ENXIO;

	md = mmc_blk_get(inode->i_bdev->bd_disk);
	if (md) {
	if (md->usage == 2)
	check_disk_change(inode->i_bdev);
	ret = 0;

	if ((filp->f_mode & FMODE_WRITE) &&
	mmc_blk_readonly(md->queue.card))
	ret = -EROFS;
	}

	return ret;
	}

	static int mmc_blk_release(struct inode inode, struct file filp)
	{
	struct mmc_blk_data *md = inode->i_bdev->bd_disk->private_data;

	mmc_blk_put(md);
	return 0;
	}

	static int
	mmc_blk_ioctl(struct inode inode, struct file filp, unsigned int cmd, unsigned long arg)
	{
	struct block_device *bdev = inode->i_bdev;

	if (cmd == HDIO_GETGEO) {
	struct hd_geometry geo;

	memset(&geo, 0, sizeof(struct hd_geometry));

	geo.cylinders = get_capacity(bdev->bd_disk) / (4 * 16);
	geo.heads = 4;
	geo.sectors = 16;
	geo.start = get_start_sect(bdev);

	return copy_to_user((void __user *)arg, &geo, sizeof(geo))
	? -EFAULT : 0;
	}

	return -ENOTTY;
	}

	static struct block_device_operations mmc_bdops = {
	.open = mmc_blk_open,
	.release = mmc_blk_release,
	.ioctl = mmc_blk_ioctl,
	.owner = THIS_MODULE,
	};

	struct mmc_blk_request {
	struct mmc_request mrq;
	struct mmc_command cmd;
	struct mmc_command stop;
	struct mmc_data data;
	};

	static int mmc_blk_prep_rq(struct mmc_queue mq, struct request req)
	{
	struct mmc_blk_data *md = mq->data;
	int stat = BLKPREP_OK;

	/*
	* If we have no device, we haven't finished initialising.
	*/
	if (!md \|\| !mq->card) {
	printk(KERN_ERR "%s: killing request - no device/host\n",
	req->rq_disk->disk_name);
	stat = BLKPREP_KILL;
	}

	return stat;
	}

	static int mmc_blk_issue_rq(struct mmc_queue mq, struct request req)
	{
	struct mmc_blk_data *md = mq->data;
	struct mmc_card *card = md->queue.card;
	int ret;

	if (mmc_card_claim_host(card))
	goto cmd_err;

	do {
	struct mmc_blk_request brq;
	struct mmc_command cmd;

	memset(&brq, 0, sizeof(struct mmc_blk_request));
	brq.mrq.cmd = &brq.cmd;
	brq.mrq.data = &brq.data;

	brq.cmd.arg = req->sector << 9;
	brq.cmd.flags = MMC_RSP_R1;
	brq.data.timeout_ns = card->csd.tacc_ns * 10;
	brq.data.timeout_clks = card->csd.tacc_clks * 10;
	brq.data.blksz_bits = md->block_bits;
	brq.data.blocks = req->nr_sectors >> (md->block_bits - 9);
	brq.stop.opcode = MMC_STOP_TRANSMISSION;
	brq.stop.arg = 0;
	brq.stop.flags = MMC_RSP_R1B;

	if (rq_data_dir(req) == READ) {
	brq.cmd.opcode = brq.data.blocks > 1 ? MMC_READ_MULTIPLE_BLOCK : MMC_READ_SINGLE_BLOCK;
	brq.data.flags \|= MMC_DATA_READ;
	} else {
	brq.cmd.opcode = MMC_WRITE_BLOCK;
	brq.data.flags \|= MMC_DATA_WRITE;
	brq.data.blocks = 1;
	}
	brq.mrq.stop = brq.data.blocks > 1 ? &brq.stop : NULL;

	brq.data.sg = mq->sg;
	brq.data.sg_len = blk_rq_map_sg(req->q, req, brq.data.sg);

	mmc_wait_for_req(card->host, &brq.mrq);
	if (brq.cmd.error) {
	printk(KERN_ERR "%s: error %d sending read/write command\n",
	req->rq_disk->disk_name, brq.cmd.error);
	goto cmd_err;
	}

	if (brq.data.error) {
	printk(KERN_ERR "%s: error %d transferring data\n",
	req->rq_disk->disk_name, brq.data.error);
	goto cmd_err;
	}

	if (brq.stop.error) {
	printk(KERN_ERR "%s: error %d sending stop command\n",
	req->rq_disk->disk_name, brq.stop.error);
	goto cmd_err;
	}

	do {
	int err;

	cmd.opcode = MMC_SEND_STATUS;
	cmd.arg = card->rca << 16;
	cmd.flags = MMC_RSP_R1;
	err = mmc_wait_for_cmd(card->host, &cmd, 5);
	if (err) {
	printk(KERN_ERR "%s: error %d requesting status\n",
	req->rq_disk->disk_name, err);
	goto cmd_err;
	}
	} while (!(cmd.resp[0] & R1_READY_FOR_DATA));

	#if 0
	if (cmd.resp[0] & ~0x00000900)
	printk(KERN_ERR "%s: status = %08x\n",
	req->rq_disk->disk_name, cmd.resp[0]);
	if (mmc_decode_status(cmd.resp))
	goto cmd_err;
	#endif

	/*
	* A block was successfully transferred.
	*/
	spin_lock_irq(&md->lock);
	ret = end_that_request_chunk(req, 1, brq.data.bytes_xfered);
	if (!ret) {
	/*
	* The whole request completed successfully.
	*/
	add_disk_randomness(req->rq_disk);
	blkdev_dequeue_request(req);
	end_that_request_last(req);
	}
	spin_unlock_irq(&md->lock);
	} while (ret);

	mmc_card_release_host(card);

	return 1;

	cmd_err:
	mmc_card_release_host(card);

	/*
	* This is a little draconian, but until we get proper
	* error handling sorted out here, its the best we can
	* do - especially as some hosts have no idea how much
	* data was transferred before the error occurred.
	*/
	spin_lock_irq(&md->lock);
	do {
	ret = end_that_request_chunk(req, 0,
	req->current_nr_sectors << 9);
	} while (ret);

	add_disk_randomness(req->rq_disk);
	blkdev_dequeue_request(req);
	end_that_request_last(req);
	spin_unlock_irq(&md->lock);

	return 0;
	}

	#define MMC_NUM_MINORS (256 >> MMC_SHIFT)

	static unsigned long dev_use[MMC_NUM_MINORS/(8*sizeof(unsigned long))];

	static struct mmc_blk_data mmc_blk_alloc(struct mmc_card card)
	{
	struct mmc_blk_data *md;
	int devidx, ret;

	devidx = find_first_zero_bit(dev_use, MMC_NUM_MINORS);
	if (devidx >= MMC_NUM_MINORS)
	return ERR_PTR(-ENOSPC);
	__set_bit(devidx, dev_use);

	md = kmalloc(sizeof(struct mmc_blk_data), GFP_KERNEL);
	if (md) {
	memset(md, 0, sizeof(struct mmc_blk_data));

	md->disk = alloc_disk(1 << MMC_SHIFT);
	if (md->disk == NULL) {
	kfree(md);
	md = ERR_PTR(-ENOMEM);
	goto out;
	}

	spin_lock_init(&md->lock);
	md->usage = 1;

	ret = mmc_init_queue(&md->queue, card, &md->lock);
	if (ret) {
	put_disk(md->disk);
	kfree(md);
	md = ERR_PTR(ret);
	goto out;
	}
	md->queue.prep_fn = mmc_blk_prep_rq;
	md->queue.issue_fn = mmc_blk_issue_rq;
	md->queue.data = md;

	md->disk->major = major;
	md->disk->first_minor = devidx << MMC_SHIFT;
	md->disk->fops = &mmc_bdops;
	md->disk->private_data = md;
	md->disk->queue = md->queue.queue;
	md->disk->driverfs_dev = &card->dev;

	/*
	* As discussed on lkml, GENHD_FL_REMOVABLE should:
	*
	* - be set for removable media with permanent block devices
	* - be unset for removable block devices with permanent media
	*
	* Since MMC block devices clearly fall under the second
	* case, we do not set GENHD_FL_REMOVABLE. Userspace
	* should use the block device creation/destruction hotplug
	* messages to tell when the card is present.
	*/

	sprintf(md->disk->disk_name, "mmcblk%d", devidx);
	sprintf(md->disk->devfs_name, "mmc/blk%d", devidx);

	md->block_bits = card->csd.read_blkbits;

	blk_queue_hardsect_size(md->queue.queue, 1 << md->block_bits);
	set_capacity(md->disk, card->csd.capacity);
	}
	out:
	return md;
	}

	static int
	mmc_blk_set_blksize(struct mmc_blk_data md, struct mmc_card card)
	{
	struct mmc_command cmd;
	int err;

	mmc_card_claim_host(card);
	cmd.opcode = MMC_SET_BLOCKLEN;
	cmd.arg = 1 << card->csd.read_blkbits;
	cmd.flags = MMC_RSP_R1;
	err = mmc_wait_for_cmd(card->host, &cmd, 5);
	mmc_card_release_host(card);

	if (err) {
	printk(KERN_ERR "%s: unable to set block size to %d: %d\n",
	md->disk->disk_name, cmd.arg, err);
	return -EINVAL;
	}

	return 0;
	}

	static int mmc_blk_probe(struct mmc_card *card)
	{
	struct mmc_blk_data *md;
	int err;

	/*
	* Check that the card supports the command class(es) we need.
	*/
	if (!(card->csd.cmdclass & CCC_BLOCK_READ))
	return -ENODEV;

	if (card->csd.read_blkbits < 9) {
	printk(KERN_WARNING "%s: read blocksize too small (%u)\n",
	mmc_card_id(card), 1 << card->csd.read_blkbits);
	return -ENODEV;
	}

	md = mmc_blk_alloc(card);
	if (IS_ERR(md))
	return PTR_ERR(md);

	err = mmc_blk_set_blksize(md, card);
	if (err)
	goto out;

	printk(KERN_INFO "%s: %s %s %dKiB %s\n",
	md->disk->disk_name, mmc_card_id(card), mmc_card_name(card),
	(card->csd.capacity << card->csd.read_blkbits) / 1024,
	mmc_blk_readonly(card)?"(ro)":"");

	mmc_set_drvdata(card, md);
	add_disk(md->disk);
	return 0;

	out:
	mmc_blk_put(md);

	return err;
	}

	static void mmc_blk_remove(struct mmc_card *card)
	{
	struct mmc_blk_data *md = mmc_get_drvdata(card);

	if (md) {
	int devidx;

	del_gendisk(md->disk);

	/*
	* I think this is needed.
	*/
	md->disk->queue = NULL;

	devidx = md->disk->first_minor >> MMC_SHIFT;
	__clear_bit(devidx, dev_use);

	mmc_blk_put(md);
	}
	mmc_set_drvdata(card, NULL);
	}

	#ifdef CONFIG_PM
	static int mmc_blk_suspend(struct mmc_card *card, pm_message_t state)
	{
	struct mmc_blk_data *md = mmc_get_drvdata(card);

	if (md) {
	mmc_queue_suspend(&md->queue);
	}
	return 0;
	}

	static int mmc_blk_resume(struct mmc_card *card)
	{
	struct mmc_blk_data *md = mmc_get_drvdata(card);

	if (md) {
	mmc_blk_set_blksize(md, card);
	mmc_queue_resume(&md->queue);
	}
	return 0;
	}
	#else
	#define mmc_blk_suspend NULL
	#define mmc_blk_resume NULL
	#endif

	static struct mmc_driver mmc_driver = {
	.drv = {
	.name = "mmcblk",
	},
	.probe = mmc_blk_probe,
	.remove = mmc_blk_remove,
	.suspend = mmc_blk_suspend,
	.resume = mmc_blk_resume,
	};

	static int __init mmc_blk_init(void)
	{
	int res = -ENOMEM;

	res = register_blkdev(major, "mmc");
	if (res < 0) {
	printk(KERN_WARNING "Unable to get major %d for MMC media: %d\n",
	major, res);
	goto out;
	}
	if (major == 0)
	major = res;

	devfs_mk_dir("mmc");
	return mmc_register_driver(&mmc_driver);

	out:
	return res;
	}

	static void __exit mmc_blk_exit(void)
	{
	mmc_unregister_driver(&mmc_driver);
	devfs_remove("mmc");
	unregister_blkdev(major, "mmc");
	}

	module_init(mmc_blk_init);
	module_exit(mmc_blk_exit);

	MODULE_LICENSE("GPL");
	MODULE_DESCRIPTION("Multimedia Card (MMC) block device driver");

	module_param(major, int, 0444);
	MODULE_PARM_DESC(major, "specify the major device number for MMC block driver");