path: root/drivers/mmc/card/block.c

/*
 * Block driver for media (i.e., flash cards)
 *
 * Copyright 2002 Hewlett-Packard Company
 * Copyright 2005-2008 Pierre Ossman
 *
 * 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/kernel.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/hdreg.h>
#include <linux/kdev_t.h>
#include <linux/blkdev.h>
#include <linux/mutex.h>
#include <linux/scatterlist.h>
#include <linux/string_helpers.h>

#include <linux/mmc/card.h>
#include <linux/mmc/host.h>
#include <linux/mmc/mmc.h>
#include <linux/mmc/sd.h>

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

#include "queue.h"

MODULE_ALIAS("mmc:block");
#ifdef MODULE_PARAM_PREFIX
#undef MODULE_PARAM_PREFIX
#endif
#define MODULE_PARAM_PREFIX "mmcblk."

#define INAND_CMD38_ARG_EXT_CSD  113
#define INAND_CMD38_ARG_ERASE    0x00
#define INAND_CMD38_ARG_TRIM     0x01
#define INAND_CMD38_ARG_SECERASE 0x80
#define INAND_CMD38_ARG_SECTRIM1 0x81
#define INAND_CMD38_ARG_SECTRIM2 0x88

#define REL_WRITES_SUPPORTED(card) (mmc_card_mmc((card)) &&	\
    (((card)->ext_csd.rel_param & EXT_CSD_WR_REL_PARAM_EN) ||	\
     ((card)->ext_csd.rel_sectors)))

static DEFINE_MUTEX(block_mutex);

/*
 * The defaults come from config options but can be overriden by module
 * or bootarg options.
 */
static int perdev_minors = CONFIG_MMC_BLOCK_MINORS;

/*
 * We've only got one major, so number of mmcblk devices is
 * limited to 256 / number of minors per device.
 */
static int max_devices;

/* 256 minors, so at most 256 separate devices */
static DECLARE_BITMAP(dev_use, 256);
static DECLARE_BITMAP(name_use, 256);

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

	unsigned int	usage;
	unsigned int	read_only;
	unsigned int	part_type;
	unsigned int	name_idx;

	/*
	 * Only set in main mmc_blk_data associated
	 * with mmc_card with mmc_set_drvdata, and keeps
	 * track of the current selected device partition.
	 */
	unsigned int	part_curr;
	struct device_attribute force_ro;
};

static DEFINE_MUTEX(open_lock);

module_param(perdev_minors, int, 0444);
MODULE_PARM_DESC(perdev_minors, "Minors numbers to allocate per device");

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

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

	return md;
}

static inline int mmc_get_devidx(struct gendisk *disk)
{
	int devmaj = MAJOR(disk_devt(disk));
	int devidx = MINOR(disk_devt(disk)) / perdev_minors;

	if (!devmaj)
		devidx = disk->first_minor / perdev_minors;
	return devidx;
}

static void mmc_blk_put(struct mmc_blk_data *md)
{
	mutex_lock(&open_lock);
	md->usage--;
	if (md->usage == 0) {
		int devidx = mmc_get_devidx(md->disk);
		blk_cleanup_queue(md->queue.queue);

		__clear_bit(devidx, dev_use);

		put_disk(md->disk);
		kfree(md);
	}
	mutex_unlock(&open_lock);
}

static ssize_t force_ro_show(struct device *dev, struct device_attribute *attr,
			     char *buf)
{
	int ret;
	struct mmc_blk_data *md = mmc_blk_get(dev_to_disk(dev));

	ret = snprintf(buf, PAGE_SIZE, "%d",
		       get_disk_ro(dev_to_disk(dev)) ^
		       md->read_only);
	mmc_blk_put(md);
	return ret;
}

static ssize_t force_ro_store(struct device *dev,