mmc: block: improve error recovery from command channel errors

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / 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/delay.h>
#include <linux/capability.h>
#include <linux/compat.h>

#include <linux/mmc/ioctl.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

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    flags;
#define MMC_BLK_CMD23   (1 << 0)        /* Can do SET_BLOCK_COUNT for multiblock */
#define MMC_BLK_REL_WR  (1 << 1)        /* MMC Reliable write support */

        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, struct device_attribute *attr,
                              const char *buf, size_t count)
{
        int ret;
        char *end;
        struct mmc_blk_data *md = mmc_blk_get(dev_to_disk(dev));
        unsigned long set = simple_strtoul(buf, &end, 0);
        if (end == buf) {
                ret = -EINVAL;
                goto out;
        }

        set_disk_ro(dev_to_disk(dev), set || md->read_only);
        ret = count;
out:
        mmc_blk_put(md);
        return ret;
}

static int mmc_blk_open(struct block_device *bdev, fmode_t mode)
{
        struct mmc_blk_data *md = mmc_blk_get(bdev->bd_disk);
        int ret = -ENXIO;

        mutex_lock(&block_mutex);
        if (md) {
                if (md->usage == 2)
                        check_disk_change(bdev);
                ret = 0;

                if ((mode & FMODE_WRITE) && md->read_only) {
                        mmc_blk_put(md);
                        ret = -EROFS;
                }
        }
        mutex_unlock(&block_mutex);

        return ret;
}

static int mmc_blk_release(struct gendisk *disk, fmode_t mode)
{
        struct mmc_blk_data *md = disk->private_data;

        mutex_lock(&block_mutex);
        mmc_blk_put(md);
        mutex_unlock(&block_mutex);
        return 0;
}

static int
mmc_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo)
{
        geo->cylinders = get_capacity(bdev->bd_disk) / (4 * 16);
        geo->heads = 4;
        geo->sectors = 16;
        return 0;
}

struct mmc_blk_ioc_data {
        struct mmc_ioc_cmd ic;
        unsigned char *buf;
        u64 buf_bytes;
};

static struct mmc_blk_ioc_data *mmc_blk_ioctl_copy_from_user(
        struct mmc_ioc_cmd __user *user)
{
        struct mmc_blk_ioc_data *idata;
        int err;

        idata = kzalloc(sizeof(*idata), GFP_KERNEL);
        if (!idata) {
                err = -ENOMEM;
                goto out;
        }

        if (copy_from_user(&idata->ic, user, sizeof(idata->ic))) {
                err = -EFAULT;
                goto idata_err;
        }

        idata->buf_bytes = (u64) idata->ic.blksz * idata->ic.blocks;
        if (idata->buf_bytes > MMC_IOC_MAX_BYTES) {
                err = -EOVERFLOW;
                goto idata_err;
        }

        idata->buf = kzalloc(idata->buf_bytes, GFP_KERNEL);
        if (!idata->buf) {
                err = -ENOMEM;
                goto idata_err;
        }

        if (copy_from_user(idata->buf, (void __user *)(unsigned long)
                                        idata->ic.data_ptr, idata->buf_bytes)) {
                err = -EFAULT;
                goto copy_err;
        }

        return idata;

copy_err:
        kfree(idata->buf);
idata_err:
        kfree(idata);
out:
        return ERR_PTR(err);
}

static int mmc_blk_ioctl_cmd(struct block_device *bdev,
        struct mmc_ioc_cmd __user *ic_ptr)
{
        struct mmc_blk_ioc_data *idata;
        struct mmc_blk_data *md;
        struct mmc_card *card;
        struct mmc_command cmd = {0};
        struct mmc_data data = {0};
        struct mmc_request mrq = {0};
        struct scatterlist sg;
        int err;

        /*
         * The caller must have CAP_SYS_RAWIO, and must be calling this on the
         * whole block device, not on a partition.  This prevents overspray
         * between sibling partitions.
         */
        if ((!capable(CAP_SYS_RAWIO)) || (bdev != bdev->bd_contains))
                return -EPERM;

        idata = mmc_blk_ioctl_copy_from_user(ic_ptr);
        if (IS_ERR(idata))
                return PTR_ERR(idata);

        cmd.opcode = idata->ic.opcode;
        cmd.arg = idata->ic.arg;
        cmd.flags = idata->ic.flags;

        data.sg = &sg;
        data.sg_len = 1;
        data.blksz = idata->ic.blksz;
        data.blocks = idata->ic.blocks;

        sg_init_one(data.sg, idata->buf, idata->buf_bytes);

        if (idata->ic.write_flag)
                data.flags = MMC_DATA_WRITE;
        else
                data.flags = MMC_DATA_READ;

        mrq.cmd = &cmd;
        mrq.data = &data;

        md = mmc_blk_get(bdev->bd_disk);
        if (!md) {
                err = -EINVAL;
                goto cmd_done;
        }

        card = md->queue.card;
        if (IS_ERR(card)) {
                err = PTR_ERR(card);
                goto cmd_done;
        }

        mmc_claim_host(card->host);

        if (idata->ic.is_acmd) {
                err = mmc_app_cmd(card->host, card);
                if (err)
                        goto cmd_rel_host;
        }

        /* data.flags must already be set before doing this. */
        mmc_set_data_timeout(&data, card);
        /* Allow overriding the timeout_ns for empirical tuning. */
        if (idata->ic.data_timeout_ns)
                data.timeout_ns = idata->ic.data_timeout_ns;

        if ((cmd.flags & MMC_RSP_R1B) == MMC_RSP_R1B) {
                /*
                 * Pretend this is a data transfer and rely on the host driver
                 * to compute timeout.  When all host drivers support
                 * cmd.cmd_timeout for R1B, this can be changed to:
                 *
                 *     mrq.data = NULL;
                 *     cmd.cmd_timeout = idata->ic.cmd_timeout_ms;
                 */
                data.timeout_ns = idata->ic.cmd_timeout_ms * 1000000;
        }

        mmc_wait_for_req(card->host, &mrq);

        if (cmd.error) {
                dev_err(mmc_dev(card->host), "%s: cmd error %d\n",
                                                __func__, cmd.error);
                err = cmd.error;
                goto cmd_rel_host;
        }
        if (data.error) {
                dev_err(mmc_dev(card->host), "%s: data error %d\n",
                                                __func__, data.error);
                err = data.error;
                goto cmd_rel_host;
        }

        /*
         * According to the SD specs, some commands require a delay after
         * issuing the command.
         */
        if (idata->ic.postsleep_min_us)
                usleep_range(idata->ic.postsleep_min_us, idata->ic.postsleep_max_us);

        if (copy_to_user(&(ic_ptr->response), cmd.resp, sizeof(cmd.resp))) {
                err = -EFAULT;
                goto cmd_rel_host;
        }

        if (!idata->ic.write_flag) {
                if (copy_to_user((void __user *)(unsigned long) idata->ic.data_ptr,
                                                idata->buf, idata->buf_bytes)) {
                        err = -EFAULT;
                        goto cmd_rel_host;
                }
        }

cmd_rel_host:
        mmc_release_host(card->host);

cmd_done:
        mmc_blk_put(md);
        kfree(idata->buf);
        kfree(idata);
        return err;
}

static int mmc_blk_ioctl(struct block_device *bdev, fmode_t mode,
        unsigned int cmd, unsigned long arg)
{
        int ret = -EINVAL;
        if (cmd == MMC_IOC_CMD)
                ret = mmc_blk_ioctl_cmd(bdev, (struct mmc_ioc_cmd __user *)arg);
        return ret;
}

#ifdef CONFIG_COMPAT
static int mmc_blk_compat_ioctl(struct block_device *bdev, fmode_t mode,
        unsigned int cmd, unsigned long arg)
{
        return mmc_blk_ioctl(bdev, mode, cmd, (unsigned long) compat_ptr(arg));
}
#endif

static const struct block_device_operations mmc_bdops = {
        .open                   = mmc_blk_open,
        .release                = mmc_blk_release,
        .getgeo                 = mmc_blk_getgeo,
        .owner                  = THIS_MODULE,
        .ioctl                  = mmc_blk_ioctl,
#ifdef CONFIG_COMPAT
        .compat_ioctl           = mmc_blk_compat_ioctl,
#endif
};

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

static inline int mmc_blk_part_switch(struct mmc_card *card,
                                      struct mmc_blk_data *md)
{
        int ret;
        struct mmc_blk_data *main_md = mmc_get_drvdata(card);
        if (main_md->part_curr == md->part_type)
                return 0;

        if (mmc_card_mmc(card)) {
                card->ext_csd.part_config &= ~EXT_CSD_PART_CONFIG_ACC_MASK;
                card->ext_csd.part_config |= md->part_type;

                ret = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
                                 EXT_CSD_PART_CONFIG, card->ext_csd.part_config,
                                 card->ext_csd.part_time);
                if (ret)
                        return ret;
}

        main_md->part_curr = md->part_type;
        return 0;
}

static u32 mmc_sd_num_wr_blocks(struct mmc_card *card)
{
        int err;
        u32 result;
        __be32 *blocks;

        struct mmc_request mrq = {0};
        struct mmc_command cmd = {0};
        struct mmc_data data = {0};
        unsigned int timeout_us;

        struct scatterlist sg;

        cmd.opcode = MMC_APP_CMD;
        cmd.arg = card->rca << 16;
        cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_AC;

        err = mmc_wait_for_cmd(card->host, &cmd, 0);
        if (err)
                return (u32)-1;
        if (!mmc_host_is_spi(card->host) && !(cmd.resp[0] & R1_APP_CMD))
                return (u32)-1;

        memset(&cmd, 0, sizeof(struct mmc_command));

        cmd.opcode = SD_APP_SEND_NUM_WR_BLKS;
        cmd.arg = 0;
        cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_ADTC;

        data.timeout_ns = card->csd.tacc_ns * 100;
        data.timeout_clks = card->csd.tacc_clks * 100;

        timeout_us = data.timeout_ns / 1000;
        timeout_us += data.timeout_clks * 1000 /
                (card->host->ios.clock / 1000);

        if (timeout_us > 100000) {
                data.timeout_ns = 100000000;
                data.timeout_clks = 0;
        }

        data.blksz = 4;
        data.blocks = 1;
        data.flags = MMC_DATA_READ;
        data.sg = &sg;
        data.sg_len = 1;

        mrq.cmd = &cmd;
        mrq.data = &data;

        blocks = kmalloc(4, GFP_KERNEL);
        if (!blocks)
                return (u32)-1;

        sg_init_one(&sg, blocks, 4);

        mmc_wait_for_req(card->host, &mrq);

        result = ntohl(*blocks);
        kfree(blocks);

        if (cmd.error || data.error)
                result = (u32)-1;

        return result;
}

static int send_stop(struct mmc_card *card, u32 *status)
{
        struct mmc_command cmd = {0};
        int err;

        cmd.opcode = MMC_STOP_TRANSMISSION;
        cmd.flags = MMC_RSP_SPI_R1B | MMC_RSP_R1B | MMC_CMD_AC;
        err = mmc_wait_for_cmd(card->host, &cmd, 5);
        if (err == 0)
                *status = cmd.resp[0];
        return err;
}

static int get_card_status(struct mmc_card *card, u32 *status, int retries)
{
        struct mmc_command cmd = {0};
        int err;

        cmd.opcode = MMC_SEND_STATUS;
        if (!mmc_host_is_spi(card->host))
                cmd.arg = card->rca << 16;
        cmd.flags = MMC_RSP_SPI_R2 | MMC_RSP_R1 | MMC_CMD_AC;
        err = mmc_wait_for_cmd(card->host, &cmd, retries);
        if (err == 0)
                *status = cmd.resp[0];
        return err;
}

#define ERR_RETRY       2
#define ERR_ABORT       1
#define ERR_CONTINUE    0

static int mmc_blk_cmd_error(struct request *req, const char *name, int error,
        bool status_valid, u32 status)
{
        switch (error) {
        case -EILSEQ:
                /* response crc error, retry the r/w cmd */
                pr_err("%s: %s sending %s command, card status %#x\n",
                        req->rq_disk->disk_name, "response CRC error",
                        name, status);
                return ERR_RETRY;

        case -ETIMEDOUT:
                pr_err("%s: %s sending %s command, card status %#x\n",
                        req->rq_disk->disk_name, "timed out", name, status);

                /* If the status cmd initially failed, retry the r/w cmd */
                if (!status_valid)
                        return ERR_RETRY;

                /*
                 * If it was a r/w cmd crc error, or illegal command
                 * (eg, issued in wrong state) then retry - we should
                 * have corrected the state problem above.
                 */
                if (status & (R1_COM_CRC_ERROR | R1_ILLEGAL_COMMAND))
                        return ERR_RETRY;

                /* Otherwise abort the command */
                return ERR_ABORT;

        default:
                /* We don't understand the error code the driver gave us */
                pr_err("%s: unknown error %d sending read/write command, card status %#x\n",
                       req->rq_disk->disk_name, error, status);
                return ERR_ABORT;
        }
}

/*
 * Initial r/w and stop cmd error recovery.
 * We don't know whether the card received the r/w cmd or not, so try to
 * restore things back to a sane state.  Essentially, we do this as follows:
 * - Obtain card status.  If the first attempt to obtain card status fails,
 *   the status word will reflect the failed status cmd, not the failed
 *   r/w cmd.  If we fail to obtain card status, it suggests we can no
 *   longer communicate with the card.
 * - Check the card state.  If the card received the cmd but there was a
 *   transient problem with the response, it might still be in a data transfer
 *   mode.  Try to send it a stop command.  If this fails, we can't recover.
 * - If the r/w cmd failed due to a response CRC error, it was probably
 *   transient, so retry the cmd.
 * - If the r/w cmd timed out, but we didn't get the r/w cmd status, retry.
 * - If the r/w cmd timed out, and the r/w cmd failed due to CRC error or
 *   illegal cmd, retry.
 * Otherwise we don't understand what happened, so abort.
 */
static int mmc_blk_cmd_recovery(struct mmc_card *card, struct request *req,
        struct mmc_blk_request *brq)
{
        bool prev_cmd_status_valid = true;
        u32 status, stop_status = 0;
        int err, retry;

        /*
         * Try to get card status which indicates both the card state
         * and why there was no response.  If the first attempt fails,
         * we can't be sure the returned status is for the r/w command.
         */
        for (retry = 2; retry >= 0; retry--) {
                err = get_card_status(card, &status, 0);
                if (!err)
                        break;

                prev_cmd_status_valid = false;
                pr_err("%s: error %d sending status command, %sing\n",
                       req->rq_disk->disk_name, err, retry ? "retry" : "abort");
        }

        /* We couldn't get a response from the card.  Give up. */
        if (err)
                return ERR_ABORT;

        /*
         * Check the current card state.  If it is in some data transfer
         * mode, tell it to stop (and hopefully transition back to TRAN.)
         */
        if (R1_CURRENT_STATE(status) == R1_STATE_DATA ||
            R1_CURRENT_STATE(status) == R1_STATE_RCV) {
                err = send_stop(card, &stop_status);
                if (err)
                        pr_err("%s: error %d sending stop command\n",
                               req->rq_disk->disk_name, err);

                /*
                 * If the stop cmd also timed out, the card is probably
                 * not present, so abort.  Other errors are bad news too.
                 */
                if (err)
                        return ERR_ABORT;
        }

        /* Check for set block count errors */
        if (brq->sbc.error)
                return mmc_blk_cmd_error(req, "SET_BLOCK_COUNT", brq->sbc.error,
                                prev_cmd_status_valid, status);

        /* Check for r/w command errors */
        if (brq->cmd.error)
                return mmc_blk_cmd_error(req, "r/w cmd", brq->cmd.error,
                                prev_cmd_status_valid, status);

        /* Now for stop errors.  These aren't fatal to the transfer. */
        pr_err("%s: error %d sending stop command, original cmd response %#x, card status %#x\n",
               req->rq_disk->disk_name, brq->stop.error,
               brq->cmd.resp[0], status);

        /*
         * Subsitute in our own stop status as this will give the error
         * state which happened during the execution of the r/w command.
         */
        if (stop_status) {
                brq->stop.resp[0] = stop_status;
                brq->stop.error = 0;
        }
        return ERR_CONTINUE;
}

static int mmc_blk_issue_discard_rq(struct mmc_queue *mq, struct request *req)
{
        struct mmc_blk_data *md = mq->data;
        struct mmc_card *card = md->queue.card;
        unsigned int from, nr, arg;
        int err = 0;

        if (!mmc_can_erase(card)) {
                err = -EOPNOTSUPP;
                goto out;
        }

        from = blk_rq_pos(req);
        nr = blk_rq_sectors(req);

        if (mmc_can_trim(card))
                arg = MMC_TRIM_ARG;
        else
                arg = MMC_ERASE_ARG;

        if (card->quirks & MMC_QUIRK_INAND_CMD38) {
                err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
                                 INAND_CMD38_ARG_EXT_CSD,
                                 arg == MMC_TRIM_ARG ?
                                 INAND_CMD38_ARG_TRIM :
                                 INAND_CMD38_ARG_ERASE,
                                 0);
                if (err)
                        goto out;
        }
        err = mmc_erase(card, from, nr, arg);
out:
        spin_lock_irq(&md->lock);
        __blk_end_request(req, err, blk_rq_bytes(req));
        spin_unlock_irq(&md->lock);

        return err ? 0 : 1;
}

static int mmc_blk_issue_secdiscard_rq(struct mmc_queue *mq,
                                       struct request *req)
{
        struct mmc_blk_data *md = mq->data;
        struct mmc_card *card = md->queue.card;
        unsigned int from, nr, arg;
        int err = 0;

        if (!mmc_can_secure_erase_trim(card)) {
                err = -EOPNOTSUPP;
                goto out;
        }

        from = blk_rq_pos(req);
        nr = blk_rq_sectors(req);

        if (mmc_can_trim(card) && !mmc_erase_group_aligned(card, from, nr))
                arg = MMC_SECURE_TRIM1_ARG;
        else
                arg = MMC_SECURE_ERASE_ARG;

        if (card->quirks & MMC_QUIRK_INAND_CMD38) {
                err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
                                 INAND_CMD38_ARG_EXT_CSD,
                                 arg == MMC_SECURE_TRIM1_ARG ?
                                 INAND_CMD38_ARG_SECTRIM1 :
                                 INAND_CMD38_ARG_SECERASE,
                                 0);
                if (err)
                        goto out;
        }
        err = mmc_erase(card, from, nr, arg);
        if (!err && arg == MMC_SECURE_TRIM1_ARG) {
                if (card->quirks & MMC_QUIRK_INAND_CMD38) {
                        err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
                                         INAND_CMD38_ARG_EXT_CSD,
                                         INAND_CMD38_ARG_SECTRIM2,
                                         0);
                        if (err)
                                goto out;
                }
                err = mmc_erase(card, from, nr, MMC_SECURE_TRIM2_ARG);
        }
out:
        spin_lock_irq(&md->lock);
        __blk_end_request(req, err, blk_rq_bytes(req));
        spin_unlock_irq(&md->lock);

        return err ? 0 : 1;
}

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

        /*
         * No-op, only service this because we need REQ_FUA for reliable
         * writes.
         */
        spin_lock_irq(&md->lock);
        __blk_end_request_all(req, 0);
        spin_unlock_irq(&md->lock);

        return 1;
}

/*
 * Reformat current write as a reliable write, supporting
 * both legacy and the enhanced reliable write MMC cards.
 * In each transfer we'll handle only as much as a single
 * reliable write can handle, thus finish the request in
 * partial completions.
 */
static inline void mmc_apply_rel_rw(struct mmc_blk_request *brq,
                                    struct mmc_card *card,
                                    struct request *req)
{
        if (!(card->ext_csd.rel_param & EXT_CSD_WR_REL_PARAM_EN)) {
                /* Legacy mode imposes restrictions on transfers. */
                if (!IS_ALIGNED(brq->cmd.arg, card->ext_csd.rel_sectors))
                        brq->data.blocks = 1;

                if (brq->data.blocks > card->ext_csd.rel_sectors)
                        brq->data.blocks = card->ext_csd.rel_sectors;
                else if (brq->data.blocks < card->ext_csd.rel_sectors)
                        brq->data.blocks = 1;
        }
}

static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *req)
{
        struct mmc_blk_data *md = mq->data;
        struct mmc_card *card = md->queue.card;
        struct mmc_blk_request brq;
        int ret = 1, disable_multi = 0, retry = 0;

        /*
         * Reliable writes are used to implement Forced Unit Access and
         * REQ_META accesses, and are supported only on MMCs.
         */
        bool do_rel_wr = ((req->cmd_flags & REQ_FUA) ||
                          (req->cmd_flags & REQ_META)) &&
                (rq_data_dir(req) == WRITE) &&
                (md->flags & MMC_BLK_REL_WR);

        do {
                u32 readcmd, writecmd;

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

                brq.cmd.arg = blk_rq_pos(req);
                if (!mmc_card_blockaddr(card))
                        brq.cmd.arg <<= 9;
                brq.cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_ADTC;
                brq.data.blksz = 512;
                brq.stop.opcode = MMC_STOP_TRANSMISSION;
                brq.stop.arg = 0;
                brq.stop.flags = MMC_RSP_SPI_R1B | MMC_RSP_R1B | MMC_CMD_AC;
                brq.data.blocks = blk_rq_sectors(req);

                /*
                 * The block layer doesn't support all sector count
                 * restrictions, so we need to be prepared for too big
                 * requests.
                 */
                if (brq.data.blocks > card->host->max_blk_count)
                        brq.data.blocks = card->host->max_blk_count;

                /*
                 * After a read error, we redo the request one sector at a time
                 * in order to accurately determine which sectors can be read
                 * successfully.
                 */
                if (disable_multi && brq.data.blocks > 1)
                        brq.data.blocks = 1;

                if (brq.data.blocks > 1 || do_rel_wr) {
                        /* SPI multiblock writes terminate using a special
                         * token, not a STOP_TRANSMISSION request.
                         */
                        if (!mmc_host_is_spi(card->host) ||
                            rq_data_dir(req) == READ)
                                brq.mrq.stop = &brq.stop;
                        readcmd = MMC_READ_MULTIPLE_BLOCK;
                        writecmd = MMC_WRITE_MULTIPLE_BLOCK;
                } else {
                        brq.mrq.stop = NULL;
                        readcmd = MMC_READ_SINGLE_BLOCK;
                        writecmd = MMC_WRITE_BLOCK;
                }
                if (rq_data_dir(req) == READ) {
                        brq.cmd.opcode = readcmd;
                        brq.data.flags |= MMC_DATA_READ;
                } else {
                        brq.cmd.opcode = writecmd;
                        brq.data.flags |= MMC_DATA_WRITE;
                }

                if (do_rel_wr)
                        mmc_apply_rel_rw(&brq, card, req);

                /*
                 * Pre-defined multi-block transfers are preferable to
                 * open ended-ones (and necessary for reliable writes).
                 * However, it is not sufficient to just send CMD23,
                 * and avoid the final CMD12, as on an error condition
                 * CMD12 (stop) needs to be sent anyway. This, coupled
                 * with Auto-CMD23 enhancements provided by some
                 * hosts, means that the complexity of dealing
                 * with this is best left to the host. If CMD23 is
                 * supported by card and host, we'll fill sbc in and let
                 * the host deal with handling it correctly. This means
                 * that for hosts that don't expose MMC_CAP_CMD23, no
                 * change of behavior will be observed.
                 *
                 * N.B: Some MMC cards experience perf degradation.
                 * We'll avoid using CMD23-bounded multiblock writes for
                 * these, while retaining features like reliable writes.
                 */

                if ((md->flags & MMC_BLK_CMD23) &&
                    mmc_op_multi(brq.cmd.opcode) &&
                    (do_rel_wr || !(card->quirks & MMC_QUIRK_BLK_NO_CMD23))) {
                        brq.sbc.opcode = MMC_SET_BLOCK_COUNT;
                        brq.sbc.arg = brq.data.blocks |
                                (do_rel_wr ? (1 << 31) : 0);
                        brq.sbc.flags = MMC_RSP_R1 | MMC_CMD_AC;
                        brq.mrq.sbc = &brq.sbc;
                }

                mmc_set_data_timeout(&brq.data, card);

                brq.data.sg = mq->sg;
                brq.data.sg_len = mmc_queue_map_sg(mq);

                /*
                 * Adjust the sg list so it is the same size as the
                 * request.
                 */
                if (brq.data.blocks != blk_rq_sectors(req)) {
                        int i, data_size = brq.data.blocks << 9;
                        struct scatterlist *sg;

                        for_each_sg(brq.data.sg, sg, brq.data.sg_len, i) {
                                data_size -= sg->length;
                                if (data_size <= 0) {
                                        sg->length += data_size;
                                        i++;
                                        break;
                                }
                        }
                        brq.data.sg_len = i;
                }

                mmc_queue_bounce_pre(mq);

                mmc_wait_for_req(card->host, &brq.mrq);

                mmc_queue_bounce_post(mq);

                /*
                 * sbc.error indicates a problem with the set block count
                 * command.  No data will have been transferred.
                 *
                 * cmd.error indicates a problem with the r/w command.  No
                 * data will have been transferred.
                 *
                 * stop.error indicates a problem with the stop command.  Data
                 * may have been transferred, or may still be transferring.
                 */
                if (brq.sbc.error || brq.cmd.error || brq.stop.error) {
                        switch (mmc_blk_cmd_recovery(card, req, &brq)) {
                        case ERR_RETRY:
                                if (retry++ < 5)
                                        continue;
                        case ERR_ABORT:
                                goto cmd_abort;
                        case ERR_CONTINUE:
                                break;
                        }
                }

                if (!mmc_host_is_spi(card->host) && rq_data_dir(req) != READ) {
                        u32 status;
                        do {
                                int err = get_card_status(card, &status, 5);
                                if (err) {
                                        printk(KERN_ERR "%s: error %d requesting status\n",
                                               req->rq_disk->disk_name, err);
                                        goto cmd_err;
                                }
                                /*
                                 * Some cards mishandle the status bits,
                                 * so make sure to check both the busy
                                 * indication and the card state.
                                 */
                        } while (!(status & R1_READY_FOR_DATA) ||
                                 (R1_CURRENT_STATE(status) == R1_STATE_PRG));
                }

                if (brq.data.error) {
                        pr_err("%s: error %d transferring data, sector %u nr %u, cmd response %#x card status %#x\n",
                                req->rq_disk->disk_name, brq.data.error,
                                (unsigned)blk_rq_pos(req),
                                (unsigned)blk_rq_sectors(req),
                                brq.cmd.resp[0], brq.stop.resp[0]);

                        if (rq_data_dir(req) == READ) {
                                if (brq.data.blocks > 1) {
                                        /* Redo read one sector at a time */
                                        pr_warning("%s: retrying using single block read\n",
                                                req->rq_disk->disk_name);
                                        disable_multi = 1;
                                        continue;
                                }

                                /*
                                 * After an error, we redo I/O one sector at a
                                 * time, so we only reach here after trying to
                                 * read a single sector.
                                 */
                                spin_lock_irq(&md->lock);
                                ret = __blk_end_request(req, -EIO, brq.data.blksz);
                                spin_unlock_irq(&md->lock);
                                continue;
                        } else {
                                goto cmd_err;
                        }
                }

                /*
                 * A block was successfully transferred.
                 */
                spin_lock_irq(&md->lock);
                ret = __blk_end_request(req, 0, brq.data.bytes_xfered);
                spin_unlock_irq(&md->lock);
        } while (ret);

        return 1;

 cmd_err:
        /*
         * If this is an SD card and we're writing, we can first
         * mark the known good sectors as ok.
         *
         * If the card is not SD, we can still ok written sectors
         * as reported by the controller (which might be less than
         * the real number of written sectors, but never more).
         */
        if (mmc_card_sd(card)) {
                u32 blocks;

                blocks = mmc_sd_num_wr_blocks(card);
                if (blocks != (u32)-1) {
                        spin_lock_irq(&md->lock);
                        ret = __blk_end_request(req, 0, blocks << 9);
                        spin_unlock_irq(&md->lock);
                }
        } else {
                spin_lock_irq(&md->lock);
                ret = __blk_end_request(req, 0, brq.data.bytes_xfered);
                spin_unlock_irq(&md->lock);
        }

 cmd_abort:
        spin_lock_irq(&md->lock);
        while (ret)
                ret = __blk_end_request(req, -EIO, blk_rq_cur_bytes(req));
        spin_unlock_irq(&md->lock);

        return 0;
}

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

        mmc_claim_host(card->host);
        ret = mmc_blk_part_switch(card, md);
        if (ret) {
                ret = 0;
                goto out;
        }

        if (req->cmd_flags & REQ_DISCARD) {
                if (req->cmd_flags & REQ_SECURE)
                        ret = mmc_blk_issue_secdiscard_rq(mq, req);
                else
                        ret = mmc_blk_issue_discard_rq(mq, req);
        } else if (req->cmd_flags & REQ_FLUSH) {
                ret = mmc_blk_issue_flush(mq, req);
        } else {
                ret = mmc_blk_issue_rw_rq(mq, req);
        }

out:
        mmc_release_host(card->host);
        return ret;
}

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

static struct mmc_blk_data *mmc_blk_alloc_req(struct mmc_card *card,
                                              struct device *parent,
                                              sector_t size,
                                              bool default_ro,
                                              const char *subname)
{
        struct mmc_blk_data *md;
        int devidx, ret;

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

        md = kzalloc(sizeof(struct mmc_blk_data), GFP_KERNEL);
        if (!md) {
                ret = -ENOMEM;
                goto out;
        }

        /*
         * !subname implies we are creating main mmc_blk_data that will be
         * associated with mmc_card with mmc_set_drvdata. Due to device
         * partitions, devidx will not coincide with a per-physical card
         * index anymore so we keep track of a name index.
         */
        if (!subname) {
                md->name_idx = find_first_zero_bit(name_use, max_devices);
                __set_bit(md->name_idx, name_use);
        }
        else
                md->name_idx = ((struct mmc_blk_data *)
                                dev_to_disk(parent)->private_data)->name_idx;

        /*
         * Set the read-only status based on the supported commands
         * and the write protect switch.
         */
        md->read_only = mmc_blk_readonly(card);

        md->disk = alloc_disk(perdev_minors);
        if (md->disk == NULL) {
                ret = -ENOMEM;
                goto err_kfree;
        }

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

        ret = mmc_init_queue(&md->queue, card, &md->lock, subname);
        if (ret)
                goto err_putdisk;

        md->queue.issue_fn = mmc_blk_issue_rq;
        md->queue.data = md;

        md->disk->major = MMC_BLOCK_MAJOR;
        md->disk->first_minor = devidx * perdev_minors;
        md->disk->fops = &mmc_bdops;
        md->disk->private_data = md;
        md->disk->queue = md->queue.queue;
        md->disk->driverfs_dev = parent;
        set_disk_ro(md->disk, md->read_only || default_ro);

        /*
         * 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.
         */

        snprintf(md->disk->disk_name, sizeof(md->disk->disk_name),
                 "mmcblk%d%s", md->name_idx, subname ? subname : "");

        blk_queue_logical_block_size(md->queue.queue, 512);
        set_capacity(md->disk, size);

        if (mmc_host_cmd23(card->host)) {
                if (mmc_card_mmc(card) ||
                    (mmc_card_sd(card) &&
                     card->scr.cmds & SD_SCR_CMD23_SUPPORT))
                        md->flags |= MMC_BLK_CMD23;
        }

        if (mmc_card_mmc(card) &&
            md->flags & MMC_BLK_CMD23 &&
            ((card->ext_csd.rel_param & EXT_CSD_WR_REL_PARAM_EN) ||
             card->ext_csd.rel_sectors)) {
                md->flags |= MMC_BLK_REL_WR;
                blk_queue_flush(md->queue.queue, REQ_FLUSH | REQ_FUA);
        }

        return md;

 err_putdisk:
        put_disk(md->disk);
 err_kfree:
        kfree(md);
 out:
        return ERR_PTR(ret);
}

static struct mmc_blk_data *mmc_blk_alloc(struct mmc_card *card)
{
        sector_t size;
        struct mmc_blk_data *md;

        if (!mmc_card_sd(card) && mmc_card_blockaddr(card)) {
                /*
                 * The EXT_CSD sector count is in number or 512 byte
                 * sectors.
                 */
                size = card->ext_csd.sectors;
        } else {
                /*
                 * The CSD capacity field is in units of read_blkbits.
                 * set_capacity takes units of 512 bytes.
                 */
                size = card->csd.capacity << (card->csd.read_blkbits - 9);
        }

        md = mmc_blk_alloc_req(card, &card->dev, size, false, NULL);
        return md;
}

static int mmc_blk_alloc_part(struct mmc_card *card,
                              struct mmc_blk_data *md,
                              unsigned int part_type,
                              sector_t size,
                              bool default_ro,
                              const char *subname)
{
        char cap_str[10];
        struct mmc_blk_data *part_md;

        part_md = mmc_blk_alloc_req(card, disk_to_dev(md->disk), size, default_ro,
                                    subname);
        if (IS_ERR(part_md))
                return PTR_ERR(part_md);
        part_md->part_type = part_type;
        list_add(&part_md->part, &md->part);

        string_get_size((u64)get_capacity(part_md->disk) << 9, STRING_UNITS_2,
                        cap_str, sizeof(cap_str));
        printk(KERN_INFO "%s: %s %s partition %u %s\n",
               part_md->disk->disk_name, mmc_card_id(card),
               mmc_card_name(card), part_md->part_type, cap_str);
        return 0;
}

static int mmc_blk_alloc_parts(struct mmc_card *card, struct mmc_blk_data *md)
{
        int ret = 0;

        if (!mmc_card_mmc(card))
                return 0;

        if (card->ext_csd.boot_size) {
                ret = mmc_blk_alloc_part(card, md, EXT_CSD_PART_CONFIG_ACC_BOOT0,
                                         card->ext_csd.boot_size >> 9,
                                         true,
                                         "boot0");
                if (ret)
                        return ret;
                ret = mmc_blk_alloc_part(card, md, EXT_CSD_PART_CONFIG_ACC_BOOT1,
                                         card->ext_csd.boot_size >> 9,
                                         true,
                                         "boot1");
                if (ret)
                        return ret;
        }

        return ret;
}

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

        mmc_claim_host(card->host);
        err = mmc_set_blocklen(card, 512);
        mmc_release_host(card->host);

        if (err) {
                printk(KERN_ERR "%s: unable to set block size to 512: %d\n",
                        md->disk->disk_name, err);
                return -EINVAL;
        }

        return 0;
}

static void mmc_blk_remove_req(struct mmc_blk_data *md)
{
        if (md) {
                if (md->disk->flags & GENHD_FL_UP) {
                        device_remove_file(disk_to_dev(md->disk), &md->force_ro);

                        /* Stop new requests from getting into the queue */
                        del_gendisk(md->disk);
                }

                /* Then flush out any already in there */
                mmc_cleanup_queue(&md->queue);
                mmc_blk_put(md);
        }
}

static void mmc_blk_remove_parts(struct mmc_card *card,
                                 struct mmc_blk_data *md)
{
        struct list_head *pos, *q;
        struct mmc_blk_data *part_md;

        __clear_bit(md->name_idx, name_use);
        list_for_each_safe(pos, q, &md->part) {
                part_md = list_entry(pos, struct mmc_blk_data, part);
                list_del(pos);
                mmc_blk_remove_req(part_md);
        }
}

static int mmc_add_disk(struct mmc_blk_data *md)
{
        int ret;

        add_disk(md->disk);
        md->force_ro.show = force_ro_show;
        md->force_ro.store = force_ro_store;
        sysfs_attr_init(&md->force_ro.attr);
        md->force_ro.attr.name = "force_ro";
        md->force_ro.attr.mode = S_IRUGO | S_IWUSR;
        ret = device_create_file(disk_to_dev(md->disk), &md->force_ro);
        if (ret)
                del_gendisk(md->disk);

        return ret;
}

static const struct mmc_fixup blk_fixups[] =
{
        MMC_FIXUP("SEM02G", 0x2, 0x100, add_quirk, MMC_QUIRK_INAND_CMD38),
        MMC_FIXUP("SEM04G", 0x2, 0x100, add_quirk, MMC_QUIRK_INAND_CMD38),
        MMC_FIXUP("SEM08G", 0x2, 0x100, add_quirk, MMC_QUIRK_INAND_CMD38),
        MMC_FIXUP("SEM16G", 0x2, 0x100, add_quirk, MMC_QUIRK_INAND_CMD38),
        MMC_FIXUP("SEM32G", 0x2, 0x100, add_quirk, MMC_QUIRK_INAND_CMD38),

        /*
         * Some MMC cards experience performance degradation with CMD23
         * instead of CMD12-bounded multiblock transfers. For now we'll
         * black list what's bad...
         * - Certain Toshiba cards.
         *
         * N.B. This doesn't affect SD cards.
         */
        MMC_FIXUP("MMC08G", 0x11, CID_OEMID_ANY, add_quirk_mmc,
                  MMC_QUIRK_BLK_NO_CMD23),
        MMC_FIXUP("MMC16G", 0x11, CID_OEMID_ANY, add_quirk_mmc,
                  MMC_QUIRK_BLK_NO_CMD23),
        MMC_FIXUP("MMC32G", 0x11, CID_OEMID_ANY, add_quirk_mmc,
                  MMC_QUIRK_BLK_NO_CMD23),
        END_FIXUP
};

static int mmc_blk_probe(struct mmc_card *card)
{
        struct mmc_blk_data *md, *part_md;
        int err;
        char cap_str[10];

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

        string_get_size((u64)get_capacity(md->disk) << 9, STRING_UNITS_2,
                        cap_str, sizeof(cap_str));
        printk(KERN_INFO "%s: %s %s %s %s\n",
                md->disk->disk_name, mmc_card_id(card), mmc_card_name(card),
                cap_str, md->read_only ? "(ro)" : "");

        if (mmc_blk_alloc_parts(card, md))
                goto out;

        mmc_set_drvdata(card, md);
        mmc_fixup_device(card, blk_fixups);

        if (mmc_add_disk(md))
                goto out;

        list_for_each_entry(part_md, &md->part, part) {
                if (mmc_add_disk(part_md))
                        goto out;
        }
        return 0;

 out:
        mmc_blk_remove_parts(card, md);
        mmc_blk_remove_req(md);
        return err;
}

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

        mmc_blk_remove_parts(card, md);
        mmc_claim_host(card->host);
        mmc_blk_part_switch(card, md);
        mmc_release_host(card->host);
        mmc_blk_remove_req(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 *part_md;
        struct mmc_blk_data *md = mmc_get_drvdata(card);

        if (md) {
                mmc_queue_suspend(&md->queue);
                list_for_each_entry(part_md, &md->part, part) {
                        mmc_queue_suspend(&part_md->queue);
                }
        }
        return 0;
}

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

        if (md) {
                mmc_blk_set_blksize(md, card);

                /*
                 * Resume involves the card going into idle state,
                 * so current partition is always the main one.
                 */
                md->part_curr = md->part_type;
                mmc_queue_resume(&md->queue);
                list_for_each_entry(part_md, &md->part, part) {
                        mmc_queue_resume(&part_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;

        if (perdev_minors != CONFIG_MMC_BLOCK_MINORS)
                pr_info("mmcblk: using %d minors per device\n", perdev_minors);

        max_devices = 256 / perdev_minors;

        res = register_blkdev(MMC_BLOCK_MAJOR, "mmc");
        if (res)
                goto out;

        res = mmc_register_driver(&mmc_driver);
        if (res)
                goto out2;

        return 0;
 out2:
        unregister_blkdev(MMC_BLOCK_MAJOR, "mmc");
 out:
        return res;
}

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

module_init(mmc_blk_init);
module_exit(mmc_blk_exit);

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