io_uring: reset -EBUSY error when io sq thread is waken up

[thirdparty/linux.git] / drivers / mmc / core / 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/cdev.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/pm_runtime.h>
#include <linux/idr.h>
#include <linux/debugfs.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 <linux/uaccess.h>

#include "queue.h"
#include "block.h"
#include "core.h"
#include "card.h"
#include "host.h"
#include "bus.h"
#include "mmc_ops.h"
#include "quirks.h"
#include "sd_ops.h"

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

/*
 * Set a 10 second timeout for polling write request busy state. Note, mmc core
 * is setting a 3 second timeout for SD cards, and SDHCI has long had a 10
 * second software timer to timeout the whole request, so 10 seconds should be
 * ample.
 */
#define MMC_BLK_TIMEOUT_MS  (10 * 1000)
#define MMC_EXTRACT_INDEX_FROM_ARG(x) ((x & 0x00FF0000) >> 16)
#define MMC_EXTRACT_VALUE_FROM_ARG(x) ((x & 0x0000FF00) >> 8)

#define mmc_req_rel_wr(req)     ((req->cmd_flags & REQ_FUA) && \
                                  (rq_data_dir(req) == WRITE))
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 (1 << 20) / number of minors per device.  It is also
 * limited by the MAX_DEVICES below.
 */
static int max_devices;

#define MAX_DEVICES 256

static DEFINE_IDA(mmc_blk_ida);
static DEFINE_IDA(mmc_rpmb_ida);

/*
 * There is one mmc_blk_data per slot.
 */
struct mmc_blk_data {
        struct device   *parent;
        struct gendisk  *disk;
        struct mmc_queue queue;
        struct list_head part;
        struct list_head rpmbs;

        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    reset_done;
#define MMC_BLK_READ            BIT(0)
#define MMC_BLK_WRITE           BIT(1)
#define MMC_BLK_DISCARD         BIT(2)
#define MMC_BLK_SECDISCARD      BIT(3)
#define MMC_BLK_CQE_RECOVERY    BIT(4)

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

        /* debugfs files (only in main mmc_blk_data) */
        struct dentry *status_dentry;
        struct dentry *ext_csd_dentry;
};

/* Device type for RPMB character devices */
static dev_t mmc_rpmb_devt;

/* Bus type for RPMB character devices */
static struct bus_type mmc_rpmb_bus_type = {
        .name = "mmc_rpmb",
};

/**
 * struct mmc_rpmb_data - special RPMB device type for these areas
 * @dev: the device for the RPMB area
 * @chrdev: character device for the RPMB area
 * @id: unique device ID number
 * @part_index: partition index (0 on first)
 * @md: parent MMC block device
 * @node: list item, so we can put this device on a list
 */
struct mmc_rpmb_data {
        struct device dev;
        struct cdev chrdev;
        int id;
        unsigned int part_index;
        struct mmc_blk_data *md;
        struct list_head node;
};

static DEFINE_MUTEX(open_lock);

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

static inline int mmc_blk_part_switch(struct mmc_card *card,
                                      unsigned int part_type);
static void mmc_blk_rw_rq_prep(struct mmc_queue_req *mqrq,
                               struct mmc_card *card,
                               int disable_multi,
                               struct mmc_queue *mq);
static void mmc_blk_hsq_req_done(struct mmc_request *mrq);

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 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_put_queue(md->queue.queue);
                ida_simple_remove(&mmc_blk_ida, devidx);
                put_disk(md->disk);
                kfree(md);
        }
        mutex_unlock(&open_lock);
}

static ssize_t power_ro_lock_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        int ret;
        struct mmc_blk_data *md = mmc_blk_get(dev_to_disk(dev));
        struct mmc_card *card = md->queue.card;
        int locked = 0;

        if (card->ext_csd.boot_ro_lock & EXT_CSD_BOOT_WP_B_PERM_WP_EN)
                locked = 2;
        else if (card->ext_csd.boot_ro_lock & EXT_CSD_BOOT_WP_B_PWR_WP_EN)
                locked = 1;

        ret = snprintf(buf, PAGE_SIZE, "%d\n", locked);

        mmc_blk_put(md);

        return ret;
}

static ssize_t power_ro_lock_store(struct device *dev,
                struct device_attribute *attr, const char *buf, size_t count)
{
        int ret;
        struct mmc_blk_data *md, *part_md;
        struct mmc_queue *mq;
        struct request *req;
        unsigned long set;

        if (kstrtoul(buf, 0, &set))
                return -EINVAL;

        if (set != 1)
                return count;

        md = mmc_blk_get(dev_to_disk(dev));
        mq = &md->queue;

        /* Dispatch locking to the block layer */
        req = blk_get_request(mq->queue, REQ_OP_DRV_OUT, 0);
        if (IS_ERR(req)) {
                count = PTR_ERR(req);
                goto out_put;
        }
        req_to_mmc_queue_req(req)->drv_op = MMC_DRV_OP_BOOT_WP;
        blk_execute_rq(mq->queue, NULL, req, 0);
        ret = req_to_mmc_queue_req(req)->drv_op_result;
        blk_put_request(req);

        if (!ret) {
                pr_info("%s: Locking boot partition ro until next power on\n",
                        md->disk->disk_name);
                set_disk_ro(md->disk, 1);

                list_for_each_entry(part_md, &md->part, part)
                        if (part_md->area_type == MMC_BLK_DATA_AREA_BOOT) {
                                pr_info("%s: Locking boot partition ro until next power on\n", part_md->disk->disk_name);
                                set_disk_ro(part_md->disk, 1);
                        }
        }
out_put:
        mmc_blk_put(md);
        return count;
}

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\n",
                       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 void 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);
}

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;
        struct mmc_rpmb_data *rpmb;
};

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 = kmalloc(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;
        }

        if (!idata->buf_bytes) {
                idata->buf = NULL;
                return idata;
        }

        idata->buf = memdup_user((void __user *)(unsigned long)
                                 idata->ic.data_ptr, idata->buf_bytes);
        if (IS_ERR(idata->buf)) {
                err = PTR_ERR(idata->buf);
                goto idata_err;
        }

        return idata;

idata_err:
        kfree(idata);
out:
        return ERR_PTR(err);
}

static int mmc_blk_ioctl_copy_to_user(struct mmc_ioc_cmd __user *ic_ptr,
                                      struct mmc_blk_ioc_data *idata)
{
        struct mmc_ioc_cmd *ic = &idata->ic;

        if (copy_to_user(&(ic_ptr->response), ic->response,
                         sizeof(ic->response)))
                return -EFAULT;

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

        return 0;
}

static int card_busy_detect(struct mmc_card *card, unsigned int timeout_ms,
                            u32 *resp_errs)
{
        unsigned long timeout = jiffies + msecs_to_jiffies(timeout_ms);
        int err = 0;
        u32 status;

        do {
                bool done = time_after(jiffies, timeout);

                err = __mmc_send_status(card, &status, 5);
                if (err) {
                        dev_err(mmc_dev(card->host),
                                "error %d requesting status\n", err);
                        return err;
                }

                /* Accumulate any response error bits seen */
                if (resp_errs)
                        *resp_errs |= status;

                /*
                 * Timeout if the device never becomes ready for data and never
                 * leaves the program state.
                 */
                if (done) {
                        dev_err(mmc_dev(card->host),
                                "Card stuck in wrong state! %s status: %#x\n",
                                 __func__, status);
                        return -ETIMEDOUT;
                }
        } while (!mmc_ready_for_data(status));

        return err;
}

static int __mmc_blk_ioctl_cmd(struct mmc_card *card, struct mmc_blk_data *md,
                               struct mmc_blk_ioc_data *idata)
{
        struct mmc_command cmd = {}, sbc = {};
        struct mmc_data data = {};
        struct mmc_request mrq = {};
        struct scatterlist sg;
        int err;
        unsigned int target_part;

        if (!card || !md || !idata)
                return -EINVAL;

        /*
         * The RPMB accesses comes in from the character device, so we
         * need to target these explicitly. Else we just target the
         * partition type for the block device the ioctl() was issued
         * on.
         */
        if (idata->rpmb) {
                /* Support multiple RPMB partitions */
                target_part = idata->rpmb->part_index;
                target_part |= EXT_CSD_PART_CONFIG_ACC_RPMB;
        } else {
                target_part = md->part_type;
        }

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

        if (idata->buf_bytes) {
                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;

                /* 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;
                }

                mrq.data = &data;
        }

        mrq.cmd = &cmd;

        err = mmc_blk_part_switch(card, target_part);
        if (err)
                return err;

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

        if (idata->rpmb) {
                sbc.opcode = MMC_SET_BLOCK_COUNT;
                /*
                 * We don't do any blockcount validation because the max size
                 * may be increased by a future standard. We just copy the
                 * 'Reliable Write' bit here.
                 */
                sbc.arg = data.blocks | (idata->ic.write_flag & BIT(31));
                sbc.flags = MMC_RSP_R1 | MMC_CMD_AC;
                mrq.sbc = &sbc;
        }

        if ((MMC_EXTRACT_INDEX_FROM_ARG(cmd.arg) == EXT_CSD_SANITIZE_START) &&
            (cmd.opcode == MMC_SWITCH))
                return mmc_sanitize(card);

        mmc_wait_for_req(card->host, &mrq);

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

        /*
         * Make sure the cache of the PARTITION_CONFIG register and
         * PARTITION_ACCESS bits is updated in case the ioctl ext_csd write
         * changed it successfully.
         */
        if ((MMC_EXTRACT_INDEX_FROM_ARG(cmd.arg) == EXT_CSD_PART_CONFIG) &&
            (cmd.opcode == MMC_SWITCH)) {
                struct mmc_blk_data *main_md = dev_get_drvdata(&card->dev);
                u8 value = MMC_EXTRACT_VALUE_FROM_ARG(cmd.arg);

                /*
                 * Update cache so the next mmc_blk_part_switch call operates
                 * on up-to-date data.
                 */
                card->ext_csd.part_config = value;
                main_md->part_curr = value & EXT_CSD_PART_CONFIG_ACC_MASK;
        }

        /*
         * 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);

        memcpy(&(idata->ic.response), cmd.resp, sizeof(cmd.resp));

        if (idata->rpmb || (cmd.flags & MMC_RSP_R1B)) {
                /*
                 * Ensure RPMB/R1B command has completed by polling CMD13
                 * "Send Status".
                 */
                err = card_busy_detect(card, MMC_BLK_TIMEOUT_MS, NULL);
        }

        return err;
}

static int mmc_blk_ioctl_cmd(struct mmc_blk_data *md,
                             struct mmc_ioc_cmd __user *ic_ptr,
                             struct mmc_rpmb_data *rpmb)
{
        struct mmc_blk_ioc_data *idata;
        struct mmc_blk_ioc_data *idatas[1];
        struct mmc_queue *mq;
        struct mmc_card *card;
        int err = 0, ioc_err = 0;
        struct request *req;

        idata = mmc_blk_ioctl_copy_from_user(ic_ptr);
        if (IS_ERR(idata))
                return PTR_ERR(idata);
        /* This will be NULL on non-RPMB ioctl():s */
        idata->rpmb = rpmb;

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

        /*
         * Dispatch the ioctl() into the block request queue.
         */
        mq = &md->queue;
        req = blk_get_request(mq->queue,
                idata->ic.write_flag ? REQ_OP_DRV_OUT : REQ_OP_DRV_IN, 0);
        if (IS_ERR(req)) {
                err = PTR_ERR(req);
                goto cmd_done;
        }
        idatas[0] = idata;
        req_to_mmc_queue_req(req)->drv_op =
                rpmb ? MMC_DRV_OP_IOCTL_RPMB : MMC_DRV_OP_IOCTL;
        req_to_mmc_queue_req(req)->drv_op_data = idatas;
        req_to_mmc_queue_req(req)->ioc_count = 1;
        blk_execute_rq(mq->queue, NULL, req, 0);
        ioc_err = req_to_mmc_queue_req(req)->drv_op_result;
        err = mmc_blk_ioctl_copy_to_user(ic_ptr, idata);
        blk_put_request(req);

cmd_done:
        kfree(idata->buf);
        kfree(idata);
        return ioc_err ? ioc_err : err;
}

static int mmc_blk_ioctl_multi_cmd(struct mmc_blk_data *md,
                                   struct mmc_ioc_multi_cmd __user *user,
                                   struct mmc_rpmb_data *rpmb)
{
        struct mmc_blk_ioc_data **idata = NULL;
        struct mmc_ioc_cmd __user *cmds = user->cmds;
        struct mmc_card *card;
        struct mmc_queue *mq;
        int i, err = 0, ioc_err = 0;
        __u64 num_of_cmds;
        struct request *req;

        if (copy_from_user(&num_of_cmds, &user->num_of_cmds,
                           sizeof(num_of_cmds)))
                return -EFAULT;

        if (!num_of_cmds)
                return 0;

        if (num_of_cmds > MMC_IOC_MAX_CMDS)
                return -EINVAL;

        idata = kcalloc(num_of_cmds, sizeof(*idata), GFP_KERNEL);
        if (!idata)
                return -ENOMEM;

        for (i = 0; i < num_of_cmds; i++) {
                idata[i] = mmc_blk_ioctl_copy_from_user(&cmds[i]);
                if (IS_ERR(idata[i])) {
                        err = PTR_ERR(idata[i]);
                        num_of_cmds = i;
                        goto cmd_err;
                }
                /* This will be NULL on non-RPMB ioctl():s */
                idata[i]->rpmb = rpmb;
        }

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


        /*
         * Dispatch the ioctl()s into the block request queue.
         */
        mq = &md->queue;
        req = blk_get_request(mq->queue,
                idata[0]->ic.write_flag ? REQ_OP_DRV_OUT : REQ_OP_DRV_IN, 0);
        if (IS_ERR(req)) {
                err = PTR_ERR(req);
                goto cmd_err;
        }
        req_to_mmc_queue_req(req)->drv_op =
                rpmb ? MMC_DRV_OP_IOCTL_RPMB : MMC_DRV_OP_IOCTL;
        req_to_mmc_queue_req(req)->drv_op_data = idata;
        req_to_mmc_queue_req(req)->ioc_count = num_of_cmds;
        blk_execute_rq(mq->queue, NULL, req, 0);
        ioc_err = req_to_mmc_queue_req(req)->drv_op_result;

        /* copy to user if data and response */
        for (i = 0; i < num_of_cmds && !err; i++)
                err = mmc_blk_ioctl_copy_to_user(&cmds[i], idata[i]);

        blk_put_request(req);

cmd_err:
        for (i = 0; i < num_of_cmds; i++) {
                kfree(idata[i]->buf);
                kfree(idata[i]);
        }
        kfree(idata);
        return ioc_err ? ioc_err : err;
}

static int mmc_blk_check_blkdev(struct block_device *bdev)
{
        /*
         * 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;
        return 0;
}

static int mmc_blk_ioctl(struct block_device *bdev, fmode_t mode,
        unsigned int cmd, unsigned long arg)
{
        struct mmc_blk_data *md;
        int ret;

        switch (cmd) {
        case MMC_IOC_CMD:
                ret = mmc_blk_check_blkdev(bdev);
                if (ret)
                        return ret;
                md = mmc_blk_get(bdev->bd_disk);
                if (!md)
                        return -EINVAL;
                ret = mmc_blk_ioctl_cmd(md,
                                        (struct mmc_ioc_cmd __user *)arg,
                                        NULL);
                mmc_blk_put(md);
                return ret;
        case MMC_IOC_MULTI_CMD:
                ret = mmc_blk_check_blkdev(bdev);
                if (ret)
                        return ret;
                md = mmc_blk_get(bdev->bd_disk);
                if (!md)
                        return -EINVAL;
                ret = mmc_blk_ioctl_multi_cmd(md,
                                        (struct mmc_ioc_multi_cmd __user *)arg,
                                        NULL);
                mmc_blk_put(md);
                return ret;
        default:
                return -EINVAL;
        }
}

#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
};

static int mmc_blk_part_switch_pre(struct mmc_card *card,
                                   unsigned int part_type)
{
        int ret = 0;

        if (part_type == EXT_CSD_PART_CONFIG_ACC_RPMB) {
                if (card->ext_csd.cmdq_en) {
                        ret = mmc_cmdq_disable(card);
                        if (ret)
                                return ret;
                }
                mmc_retune_pause(card->host);
        }

        return ret;
}

static int mmc_blk_part_switch_post(struct mmc_card *card,
                                    unsigned int part_type)
{
        int ret = 0;

        if (part_type == EXT_CSD_PART_CONFIG_ACC_RPMB) {
                mmc_retune_unpause(card->host);
                if (card->reenable_cmdq && !card->ext_csd.cmdq_en)
                        ret = mmc_cmdq_enable(card);
        }

        return ret;
}

static inline int mmc_blk_part_switch(struct mmc_card *card,
                                      unsigned int part_type)
{
        int ret = 0;
        struct mmc_blk_data *main_md = dev_get_drvdata(&card->dev);

        if (main_md->part_curr == part_type)
                return 0;

        if (mmc_card_mmc(card)) {
                u8 part_config = card->ext_csd.part_config;

                ret = mmc_blk_part_switch_pre(card, part_type);
                if (ret)
                        return ret;

                part_config &= ~EXT_CSD_PART_CONFIG_ACC_MASK;
                part_config |= part_type;

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

                card->ext_csd.part_config = part_config;

                ret = mmc_blk_part_switch_post(card, main_md->part_curr);
        }

        main_md->part_curr = part_type;
        return ret;
}

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

        struct mmc_request mrq = {};
        struct mmc_command cmd = {};
        struct mmc_data data = {};

        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 err;
        if (!mmc_host_is_spi(card->host) && !(cmd.resp[0] & R1_APP_CMD))
                return -EIO;

        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.blksz = 4;
        data.blocks = 1;
        data.flags = MMC_DATA_READ;
        data.sg = &sg;
        data.sg_len = 1;
        mmc_set_data_timeout(&data, card);

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

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

        sg_init_one(&sg, blocks, 4);

        mmc_wait_for_req(card->host, &mrq);

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

        if (cmd.error || data.error)
                return -EIO;

        *written_blocks = result;

        return 0;
}

static unsigned int mmc_blk_clock_khz(struct mmc_host *host)
{
        if (host->actual_clock)
                return host->actual_clock / 1000;

        /* Clock may be subject to a divisor, fudge it by a factor of 2. */
        if (host->ios.clock)
                return host->ios.clock / 2000;

        /* How can there be no clock */
        WARN_ON_ONCE(1);
        return 100; /* 100 kHz is minimum possible value */
}

static unsigned int mmc_blk_data_timeout_ms(struct mmc_host *host,
                                            struct mmc_data *data)
{
        unsigned int ms = DIV_ROUND_UP(data->timeout_ns, 1000000);
        unsigned int khz;

        if (data->timeout_clks) {
                khz = mmc_blk_clock_khz(host);
                ms += DIV_ROUND_UP(data->timeout_clks, khz);
        }

        return ms;
}

static int mmc_blk_reset(struct mmc_blk_data *md, struct mmc_host *host,
                         int type)
{
        int err;

        if (md->reset_done & type)
                return -EEXIST;

        md->reset_done |= type;
        err = mmc_hw_reset(host);
        /* Ensure we switch back to the correct partition */
        if (err != -EOPNOTSUPP) {
                struct mmc_blk_data *main_md =
                        dev_get_drvdata(&host->card->dev);
                int part_err;

                main_md->part_curr = main_md->part_type;
                part_err = mmc_blk_part_switch(host->card, md->part_type);
                if (part_err) {
                        /*
                         * We have failed to get back into the correct
                         * partition, so we need to abort the whole request.
                         */
                        return -ENODEV;
                }
        }
        return err;
}

static inline void mmc_blk_reset_success(struct mmc_blk_data *md, int type)
{
        md->reset_done &= ~type;
}

/*
 * The non-block commands come back from the block layer after it queued it and
 * processed it with all other requests and then they get issued in this
 * function.
 */
static void mmc_blk_issue_drv_op(struct mmc_queue *mq, struct request *req)
{
        struct mmc_queue_req *mq_rq;
        struct mmc_card *card = mq->card;
        struct mmc_blk_data *md = mq->blkdata;
        struct mmc_blk_ioc_data **idata;
        bool rpmb_ioctl;
        u8 **ext_csd;
        u32 status;
        int ret;
        int i;

        mq_rq = req_to_mmc_queue_req(req);
        rpmb_ioctl = (mq_rq->drv_op == MMC_DRV_OP_IOCTL_RPMB);

        switch (mq_rq->drv_op) {
        case MMC_DRV_OP_IOCTL:
        case MMC_DRV_OP_IOCTL_RPMB:
                idata = mq_rq->drv_op_data;
                for (i = 0, ret = 0; i < mq_rq->ioc_count; i++) {
                        ret = __mmc_blk_ioctl_cmd(card, md, idata[i]);
                        if (ret)
                                break;
                }
                /* Always switch back to main area after RPMB access */
                if (rpmb_ioctl)
                        mmc_blk_part_switch(card, 0);
                break;
        case MMC_DRV_OP_BOOT_WP:
                ret = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_BOOT_WP,
                                 card->ext_csd.boot_ro_lock |
                                 EXT_CSD_BOOT_WP_B_PWR_WP_EN,
                                 card->ext_csd.part_time);
                if (ret)
                        pr_err("%s: Locking boot partition ro until next power on failed: %d\n",
                               md->disk->disk_name, ret);
                else
                        card->ext_csd.boot_ro_lock |=
                                EXT_CSD_BOOT_WP_B_PWR_WP_EN;
                break;
        case MMC_DRV_OP_GET_CARD_STATUS:
                ret = mmc_send_status(card, &status);
                if (!ret)
                        ret = status;
                break;
        case MMC_DRV_OP_GET_EXT_CSD:
                ext_csd = mq_rq->drv_op_data;
                ret = mmc_get_ext_csd(card, ext_csd);
                break;
        default:
                pr_err("%s: unknown driver specific operation\n",
                       md->disk->disk_name);
                ret = -EINVAL;
                break;
        }
        mq_rq->drv_op_result = ret;
        blk_mq_end_request(req, ret ? BLK_STS_IOERR : BLK_STS_OK);
}

static void mmc_blk_issue_discard_rq(struct mmc_queue *mq, struct request *req)
{
        struct mmc_blk_data *md = mq->blkdata;
        struct mmc_card *card = md->queue.card;
        unsigned int from, nr;
        int err = 0, type = MMC_BLK_DISCARD;
        blk_status_t status = BLK_STS_OK;

        if (!mmc_can_erase(card)) {
                status = BLK_STS_NOTSUPP;
                goto fail;
        }

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

        do {
                err = 0;
                if (card->quirks & MMC_QUIRK_INAND_CMD38) {
                        err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
                                         INAND_CMD38_ARG_EXT_CSD,
                                         card->erase_arg == MMC_TRIM_ARG ?
                                         INAND_CMD38_ARG_TRIM :
                                         INAND_CMD38_ARG_ERASE,
                                         card->ext_csd.generic_cmd6_time);
                }
                if (!err)
                        err = mmc_erase(card, from, nr, card->erase_arg);
        } while (err == -EIO && !mmc_blk_reset(md, card->host, type));
        if (err)
                status = BLK_STS_IOERR;
        else
                mmc_blk_reset_success(md, type);
fail:
        blk_mq_end_request(req, status);
}

static void mmc_blk_issue_secdiscard_rq(struct mmc_queue *mq,
                                       struct request *req)
{
        struct mmc_blk_data *md = mq->blkdata;
        struct mmc_card *card = md->queue.card;
        unsigned int from, nr, arg;
        int err = 0, type = MMC_BLK_SECDISCARD;
        blk_status_t status = BLK_STS_OK;

        if (!(mmc_can_secure_erase_trim(card))) {
                status = BLK_STS_NOTSUPP;
                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;

retry:
        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,
                                 card->ext_csd.generic_cmd6_time);
                if (err)
                        goto out_retry;
        }

        err = mmc_erase(card, from, nr, arg);
        if (err == -EIO)
                goto out_retry;
        if (err) {
                status = BLK_STS_IOERR;
                goto out;
        }

        if (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,
                                         card->ext_csd.generic_cmd6_time);
                        if (err)
                                goto out_retry;
                }

                err = mmc_erase(card, from, nr, MMC_SECURE_TRIM2_ARG);
                if (err == -EIO)
                        goto out_retry;
                if (err) {
                        status = BLK_STS_IOERR;
                        goto out;
                }
        }

out_retry:
        if (err && !mmc_blk_reset(md, card->host, type))
                goto retry;
        if (!err)
                mmc_blk_reset_success(md, type);
out:
        blk_mq_end_request(req, status);
}

static void mmc_blk_issue_flush(struct mmc_queue *mq, struct request *req)
{
        struct mmc_blk_data *md = mq->blkdata;
        struct mmc_card *card = md->queue.card;
        int ret = 0;

        ret = mmc_flush_cache(card);
        blk_mq_end_request(req, ret ? BLK_STS_IOERR : BLK_STS_OK);
}

/*
 * 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(blk_rq_pos(req), 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;
        }
}

#define CMD_ERRORS_EXCL_OOR                                             \
        (R1_ADDRESS_ERROR |     /* Misaligned address */                \
         R1_BLOCK_LEN_ERROR |   /* Transferred block length incorrect */\
         R1_WP_VIOLATION |      /* Tried to write to protected block */ \
         R1_CARD_ECC_FAILED |   /* Card ECC failed */                   \
         R1_CC_ERROR |          /* Card controller error */             \
         R1_ERROR)              /* General/unknown error */

#define CMD_ERRORS                                                      \
        (CMD_ERRORS_EXCL_OOR |                                          \
         R1_OUT_OF_RANGE)       /* Command argument out of range */     \

static void mmc_blk_eval_resp_error(struct mmc_blk_request *brq)
{
        u32 val;

        /*
         * Per the SD specification(physical layer version 4.10)[1],
         * section 4.3.3, it explicitly states that "When the last
         * block of user area is read using CMD18, the host should
         * ignore OUT_OF_RANGE error that may occur even the sequence
         * is correct". And JESD84-B51 for eMMC also has a similar
         * statement on section 6.8.3.
         *
         * Multiple block read/write could be done by either predefined
         * method, namely CMD23, or open-ending mode. For open-ending mode,
         * we should ignore the OUT_OF_RANGE error as it's normal behaviour.
         *
         * However the spec[1] doesn't tell us whether we should also
         * ignore that for predefined method. But per the spec[1], section
         * 4.15 Set Block Count Command, it says"If illegal block count
         * is set, out of range error will be indicated during read/write
         * operation (For example, data transfer is stopped at user area
         * boundary)." In another word, we could expect a out of range error
         * in the response for the following CMD18/25. And if argument of
         * CMD23 + the argument of CMD18/25 exceed the max number of blocks,
         * we could also expect to get a -ETIMEDOUT or any error number from
         * the host drivers due to missing data response(for write)/data(for
         * read), as the cards will stop the data transfer by itself per the
         * spec. So we only need to check R1_OUT_OF_RANGE for open-ending mode.
         */

        if (!brq->stop.error) {
                bool oor_with_open_end;
                /* If there is no error yet, check R1 response */

                val = brq->stop.resp[0] & CMD_ERRORS;
                oor_with_open_end = val & R1_OUT_OF_RANGE && !brq->mrq.sbc;

                if (val && !oor_with_open_end)
                        brq->stop.error = -EIO;
        }
}

static void mmc_blk_data_prep(struct mmc_queue *mq, struct mmc_queue_req *mqrq,
                              int disable_multi, bool *do_rel_wr_p,
                              bool *do_data_tag_p)
{
        struct mmc_blk_data *md = mq->blkdata;
        struct mmc_card *card = md->queue.card;
        struct mmc_blk_request *brq = &mqrq->brq;
        struct request *req = mmc_queue_req_to_req(mqrq);
        bool do_rel_wr, do_data_tag;

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

        memset(brq, 0, sizeof(struct mmc_blk_request));

        brq->mrq.data = &brq->data;
        brq->mrq.tag = req->tag;

        brq->stop.opcode = MMC_STOP_TRANSMISSION;
        brq->stop.arg = 0;

        if (rq_data_dir(req) == READ) {
                brq->data.flags = MMC_DATA_READ;
                brq->stop.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_AC;
        } else {
                brq->data.flags = MMC_DATA_WRITE;
                brq->stop.flags = MMC_RSP_SPI_R1B | MMC_RSP_R1B | MMC_CMD_AC;
        }

        brq->data.blksz = 512;
        brq->data.blocks = blk_rq_sectors(req);
        brq->data.blk_addr = blk_rq_pos(req);

        /*
         * The command queue supports 2 priorities: "high" (1) and "simple" (0).
         * The eMMC will give "high" priority tasks priority over "simple"
         * priority tasks. Here we always set "simple" priority by not setting
         * MMC_DATA_PRIO.
         */

        /*
         * 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;

        if (brq->data.blocks > 1) {
                /*
                 * Some SD cards in SPI mode return a CRC error or even lock up
                 * completely when trying to read the last block using a
                 * multiblock read command.
                 */
                if (mmc_host_is_spi(card->host) && (rq_data_dir(req) == READ) &&
                    (blk_rq_pos(req) + blk_rq_sectors(req) ==
                     get_capacity(md->disk)))
                        brq->data.blocks--;

                /*
                 * 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;

                /*
                 * Some controllers have HW issues while operating
                 * in multiple I/O mode
                 */
                if (card->host->ops->multi_io_quirk)
                        brq->data.blocks = card->host->ops->multi_io_quirk(card,
                                                (rq_data_dir(req) == READ) ?
                                                MMC_DATA_READ : MMC_DATA_WRITE,
                                                brq->data.blocks);
        }

        if (do_rel_wr) {
                mmc_apply_rel_rw(brq, card, req);
                brq->data.flags |= MMC_DATA_REL_WR;
        }

        /*
         * Data tag is used only during writing meta data to speed
         * up write and any subsequent read of this meta data
         */
        do_data_tag = card->ext_csd.data_tag_unit_size &&
                      (req->cmd_flags & REQ_META) &&
                      (rq_data_dir(req) == WRITE) &&
                      ((brq->data.blocks * brq->data.blksz) >=
                       card->ext_csd.data_tag_unit_size);

        if (do_data_tag)
                brq->data.flags |= MMC_DATA_DAT_TAG;

        mmc_set_data_timeout(&brq->data, card);

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

        /*
         * 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;
        }

        if (do_rel_wr_p)
                *do_rel_wr_p = do_rel_wr;

        if (do_data_tag_p)
                *do_data_tag_p = do_data_tag;
}

#define MMC_CQE_RETRIES 2

static void mmc_blk_cqe_complete_rq(struct mmc_queue *mq, struct request *req)
{
        struct mmc_queue_req *mqrq = req_to_mmc_queue_req(req);
        struct mmc_request *mrq = &mqrq->brq.mrq;
        struct request_queue *q = req->q;
        struct mmc_host *host = mq->card->host;
        unsigned long flags;
        bool put_card;
        int err;

        mmc_cqe_post_req(host, mrq);

        if (mrq->cmd && mrq->cmd->error)
                err = mrq->cmd->error;
        else if (mrq->data && mrq->data->error)
                err = mrq->data->error;
        else
                err = 0;

        if (err) {
                if (mqrq->retries++ < MMC_CQE_RETRIES)
                        blk_mq_requeue_request(req, true);
                else
                        blk_mq_end_request(req, BLK_STS_IOERR);
        } else if (mrq->data) {
                if (blk_update_request(req, BLK_STS_OK, mrq->data->bytes_xfered))
                        blk_mq_requeue_request(req, true);
                else
                        __blk_mq_end_request(req, BLK_STS_OK);
        } else {
                blk_mq_end_request(req, BLK_STS_OK);
        }

        spin_lock_irqsave(&mq->lock, flags);

        mq->in_flight[mmc_issue_type(mq, req)] -= 1;

        put_card = (mmc_tot_in_flight(mq) == 0);

        mmc_cqe_check_busy(mq);

        spin_unlock_irqrestore(&mq->lock, flags);

        if (!mq->cqe_busy)
                blk_mq_run_hw_queues(q, true);

        if (put_card)
                mmc_put_card(mq->card, &mq->ctx);
}

void mmc_blk_cqe_recovery(struct mmc_queue *mq)
{
        struct mmc_card *card = mq->card;
        struct mmc_host *host = card->host;
        int err;

        pr_debug("%s: CQE recovery start\n", mmc_hostname(host));

        err = mmc_cqe_recovery(host);
        if (err)
                mmc_blk_reset(mq->blkdata, host, MMC_BLK_CQE_RECOVERY);
        else
                mmc_blk_reset_success(mq->blkdata, MMC_BLK_CQE_RECOVERY);

        pr_debug("%s: CQE recovery done\n", mmc_hostname(host));
}

static void mmc_blk_cqe_req_done(struct mmc_request *mrq)
{
        struct mmc_queue_req *mqrq = container_of(mrq, struct mmc_queue_req,
                                                  brq.mrq);
        struct request *req = mmc_queue_req_to_req(mqrq);
        struct request_queue *q = req->q;
        struct mmc_queue *mq = q->queuedata;

        /*
         * Block layer timeouts race with completions which means the normal
         * completion path cannot be used during recovery.
         */
        if (mq->in_recovery)
                mmc_blk_cqe_complete_rq(mq, req);
        else
                blk_mq_complete_request(req);
}

static int mmc_blk_cqe_start_req(struct mmc_host *host, struct mmc_request *mrq)
{
        mrq->done               = mmc_blk_cqe_req_done;
        mrq->recovery_notifier  = mmc_cqe_recovery_notifier;

        return mmc_cqe_start_req(host, mrq);
}

static struct mmc_request *mmc_blk_cqe_prep_dcmd(struct mmc_queue_req *mqrq,
                                                 struct request *req)
{
        struct mmc_blk_request *brq = &mqrq->brq;

        memset(brq, 0, sizeof(*brq));

        brq->mrq.cmd = &brq->cmd;
        brq->mrq.tag = req->tag;

        return &brq->mrq;
}

static int mmc_blk_cqe_issue_flush(struct mmc_queue *mq, struct request *req)
{
        struct mmc_queue_req *mqrq = req_to_mmc_queue_req(req);
        struct mmc_request *mrq = mmc_blk_cqe_prep_dcmd(mqrq, req);

        mrq->cmd->opcode = MMC_SWITCH;
        mrq->cmd->arg = (MMC_SWITCH_MODE_WRITE_BYTE << 24) |
                        (EXT_CSD_FLUSH_CACHE << 16) |
                        (1 << 8) |
                        EXT_CSD_CMD_SET_NORMAL;
        mrq->cmd->flags = MMC_CMD_AC | MMC_RSP_R1B;

        return mmc_blk_cqe_start_req(mq->card->host, mrq);
}

static int mmc_blk_hsq_issue_rw_rq(struct mmc_queue *mq, struct request *req)
{
        struct mmc_queue_req *mqrq = req_to_mmc_queue_req(req);
        struct mmc_host *host = mq->card->host;
        int err;

        mmc_blk_rw_rq_prep(mqrq, mq->card, 0, mq);
        mqrq->brq.mrq.done = mmc_blk_hsq_req_done;
        mmc_pre_req(host, &mqrq->brq.mrq);

        err = mmc_cqe_start_req(host, &mqrq->brq.mrq);
        if (err)
                mmc_post_req(host, &mqrq->brq.mrq, err);

        return err;
}

static int mmc_blk_cqe_issue_rw_rq(struct mmc_queue *mq, struct request *req)
{
        struct mmc_queue_req *mqrq = req_to_mmc_queue_req(req);
        struct mmc_host *host = mq->card->host;

        if (host->hsq_enabled)
                return mmc_blk_hsq_issue_rw_rq(mq, req);

        mmc_blk_data_prep(mq, mqrq, 0, NULL, NULL);

        return mmc_blk_cqe_start_req(mq->card->host, &mqrq->brq.mrq);
}

static void mmc_blk_rw_rq_prep(struct mmc_queue_req *mqrq,
                               struct mmc_card *card,
                               int disable_multi,
                               struct mmc_queue *mq)
{
        u32 readcmd, writecmd;
        struct mmc_blk_request *brq = &mqrq->brq;
        struct request *req = mmc_queue_req_to_req(mqrq);
        struct mmc_blk_data *md = mq->blkdata;
        bool do_rel_wr, do_data_tag;

        mmc_blk_data_prep(mq, mqrq, disable_multi, &do_rel_wr, &do_data_tag);

        brq->mrq.cmd = &brq->cmd;

        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;

        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;
        }
        brq->cmd.opcode = rq_data_dir(req) == READ ? readcmd : writecmd;

        /*
         * 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) ||
             do_data_tag)) {
                brq->sbc.opcode = MMC_SET_BLOCK_COUNT;
                brq->sbc.arg = brq->data.blocks |
                        (do_rel_wr ? (1 << 31) : 0) |
                        (do_data_tag ? (1 << 29) : 0);
                brq->sbc.flags = MMC_RSP_R1 | MMC_CMD_AC;
                brq->mrq.sbc = &brq->sbc;
        }
}

#define MMC_MAX_RETRIES         5
#define MMC_DATA_RETRIES        2
#define MMC_NO_RETRIES          (MMC_MAX_RETRIES + 1)

static int mmc_blk_send_stop(struct mmc_card *card, unsigned int timeout)
{
        struct mmc_command cmd = {
                .opcode = MMC_STOP_TRANSMISSION,
                .flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_AC,
                /* Some hosts wait for busy anyway, so provide a busy timeout */
                .busy_timeout = timeout,
        };

        return mmc_wait_for_cmd(card->host, &cmd, 5);
}

static int mmc_blk_fix_state(struct mmc_card *card, struct request *req)
{
        struct mmc_queue_req *mqrq = req_to_mmc_queue_req(req);
        struct mmc_blk_request *brq = &mqrq->brq;
        unsigned int timeout = mmc_blk_data_timeout_ms(card->host, &brq->data);
        int err;

        mmc_retune_hold_now(card->host);

        mmc_blk_send_stop(card, timeout);

        err = card_busy_detect(card, timeout, NULL);

        mmc_retune_release(card->host);

        return err;
}

#define MMC_READ_SINGLE_RETRIES 2

/* Single sector read during recovery */
static void mmc_blk_read_single(struct mmc_queue *mq, struct request *req)
{
        struct mmc_queue_req *mqrq = req_to_mmc_queue_req(req);
        struct mmc_request *mrq = &mqrq->brq.mrq;
        struct mmc_card *card = mq->card;
        struct mmc_host *host = card->host;
        blk_status_t error = BLK_STS_OK;
        int retries = 0;

        do {
                u32 status;
                int err;

                mmc_blk_rw_rq_prep(mqrq, card, 1, mq);

                mmc_wait_for_req(host, mrq);

                err = mmc_send_status(card, &status);
                if (err)
                        goto error_exit;

                if (!mmc_host_is_spi(host) &&
                    !mmc_ready_for_data(status)) {
                        err = mmc_blk_fix_state(card, req);
                        if (err)
                                goto error_exit;
                }

                if (mrq->cmd->error && retries++ < MMC_READ_SINGLE_RETRIES)
                        continue;

                retries = 0;

                if (mrq->cmd->error ||
                    mrq->data->error ||
                    (!mmc_host_is_spi(host) &&
                     (mrq->cmd->resp[0] & CMD_ERRORS || status & CMD_ERRORS)))
                        error = BLK_STS_IOERR;
                else
                        error = BLK_STS_OK;

        } while (blk_update_request(req, error, 512));

        return;

error_exit:
        mrq->data->bytes_xfered = 0;
        blk_update_request(req, BLK_STS_IOERR, 512);
        /* Let it try the remaining request again */
        if (mqrq->retries > MMC_MAX_RETRIES - 1)
                mqrq->retries = MMC_MAX_RETRIES - 1;
}

static inline bool mmc_blk_oor_valid(struct mmc_blk_request *brq)
{
        return !!brq->mrq.sbc;
}

static inline u32 mmc_blk_stop_err_bits(struct mmc_blk_request *brq)
{
        return mmc_blk_oor_valid(brq) ? CMD_ERRORS : CMD_ERRORS_EXCL_OOR;
}

/*
 * Check for errors the host controller driver might not have seen such as
 * response mode errors or invalid card state.
 */
static bool mmc_blk_status_error(struct request *req, u32 status)
{
        struct mmc_queue_req *mqrq = req_to_mmc_queue_req(req);
        struct mmc_blk_request *brq = &mqrq->brq;
        struct mmc_queue *mq = req->q->queuedata;
        u32 stop_err_bits;

        if (mmc_host_is_spi(mq->card->host))
                return false;

        stop_err_bits = mmc_blk_stop_err_bits(brq);

        return brq->cmd.resp[0]  & CMD_ERRORS    ||
               brq->stop.resp[0] & stop_err_bits ||
               status            & stop_err_bits ||
               (rq_data_dir(req) == WRITE && !mmc_ready_for_data(status));
}

static inline bool mmc_blk_cmd_started(struct mmc_blk_request *brq)
{
        return !brq->sbc.error && !brq->cmd.error &&
               !(brq->cmd.resp[0] & CMD_ERRORS);
}

/*
 * Requests are completed by mmc_blk_mq_complete_rq() which sets simple
 * policy:
 * 1. A request that has transferred at least some data is considered
 * successful and will be requeued if there is remaining data to
 * transfer.
 * 2. Otherwise the number of retries is incremented and the request
 * will be requeued if there are remaining retries.
 * 3. Otherwise the request will be errored out.
 * That means mmc_blk_mq_complete_rq() is controlled by bytes_xfered and
 * mqrq->retries. So there are only 4 possible actions here:
 *      1. do not accept the bytes_xfered value i.e. set it to zero
 *      2. change mqrq->retries to determine the number of retries
 *      3. try to reset the card
 *      4. read one sector at a time
 */
static void mmc_blk_mq_rw_recovery(struct mmc_queue *mq, struct request *req)
{
        int type = rq_data_dir(req) == READ ? MMC_BLK_READ : MMC_BLK_WRITE;
        struct mmc_queue_req *mqrq = req_to_mmc_queue_req(req);
        struct mmc_blk_request *brq = &mqrq->brq;
        struct mmc_blk_data *md = mq->blkdata;
        struct mmc_card *card = mq->card;
        u32 status;
        u32 blocks;
        int err;

        /*
         * Some errors the host driver might not have seen. Set the number of
         * bytes transferred to zero in that case.
         */
        err = __mmc_send_status(card, &status, 0);
        if (err || mmc_blk_status_error(req, status))
                brq->data.bytes_xfered = 0;

        mmc_retune_release(card->host);

        /*
         * Try again to get the status. This also provides an opportunity for
         * re-tuning.
         */
        if (err)
                err = __mmc_send_status(card, &status, 0);

        /*
         * Nothing more to do after the number of bytes transferred has been
         * updated and there is no card.
         */
        if (err && mmc_detect_card_removed(card->host))
                return;

        /* Try to get back to "tran" state */
        if (!mmc_host_is_spi(mq->card->host) &&
            (err || !mmc_ready_for_data(status)))
                err = mmc_blk_fix_state(mq->card, req);

        /*
         * Special case for SD cards where the card might record the number of
         * blocks written.
         */
        if (!err && mmc_blk_cmd_started(brq) && mmc_card_sd(card) &&
            rq_data_dir(req) == WRITE) {
                if (mmc_sd_num_wr_blocks(card, &blocks))
                        brq->data.bytes_xfered = 0;
                else
                        brq->data.bytes_xfered = blocks << 9;
        }

        /* Reset if the card is in a bad state */
        if (!mmc_host_is_spi(mq->card->host) &&
            err && mmc_blk_reset(md, card->host, type)) {
                pr_err("%s: recovery failed!\n", req->rq_disk->disk_name);
                mqrq->retries = MMC_NO_RETRIES;
                return;
        }

        /*
         * If anything was done, just return and if there is anything remaining
         * on the request it will get requeued.
         */
        if (brq->data.bytes_xfered)
                return;

        /* Reset before last retry */
        if (mqrq->retries + 1 == MMC_MAX_RETRIES)
                mmc_blk_reset(md, card->host, type);

        /* Command errors fail fast, so use all MMC_MAX_RETRIES */
        if (brq->sbc.error || brq->cmd.error)
                return;

        /* Reduce the remaining retries for data errors */
        if (mqrq->retries < MMC_MAX_RETRIES - MMC_DATA_RETRIES) {
                mqrq->retries = MMC_MAX_RETRIES - MMC_DATA_RETRIES;
                return;
        }

        /* FIXME: Missing single sector read for large sector size */
        if (!mmc_large_sector(card) && rq_data_dir(req) == READ &&
            brq->data.blocks > 1) {
                /* Read one sector at a time */
                mmc_blk_read_single(mq, req);
                return;
        }
}

static inline bool mmc_blk_rq_error(struct mmc_blk_request *brq)
{
        mmc_blk_eval_resp_error(brq);

        return brq->sbc.error || brq->cmd.error || brq->stop.error ||
               brq->data.error || brq->cmd.resp[0] & CMD_ERRORS;
}

static int mmc_blk_card_busy(struct mmc_card *card, struct request *req)
{
        struct mmc_queue_req *mqrq = req_to_mmc_queue_req(req);
        u32 status = 0;
        int err;

        if (mmc_host_is_spi(card->host) || rq_data_dir(req) == READ)
                return 0;

        err = card_busy_detect(card, MMC_BLK_TIMEOUT_MS, &status);

        /*
         * Do not assume data transferred correctly if there are any error bits
         * set.
         */
        if (status & mmc_blk_stop_err_bits(&mqrq->brq)) {
                mqrq->brq.data.bytes_xfered = 0;
                err = err ? err : -EIO;
        }

        /* Copy the exception bit so it will be seen later on */
        if (mmc_card_mmc(card) && status & R1_EXCEPTION_EVENT)
                mqrq->brq.cmd.resp[0] |= R1_EXCEPTION_EVENT;

        return err;
}

static inline void mmc_blk_rw_reset_success(struct mmc_queue *mq,
                                            struct request *req)
{
        int type = rq_data_dir(req) == READ ? MMC_BLK_READ : MMC_BLK_WRITE;

        mmc_blk_reset_success(mq->blkdata, type);
}

static void mmc_blk_mq_complete_rq(struct mmc_queue *mq, struct request *req)
{
        struct mmc_queue_req *mqrq = req_to_mmc_queue_req(req);
        unsigned int nr_bytes = mqrq->brq.data.bytes_xfered;

        if (nr_bytes) {
                if (blk_update_request(req, BLK_STS_OK, nr_bytes))
                        blk_mq_requeue_request(req, true);
                else
                        __blk_mq_end_request(req, BLK_STS_OK);
        } else if (!blk_rq_bytes(req)) {
                __blk_mq_end_request(req, BLK_STS_IOERR);
        } else if (mqrq->retries++ < MMC_MAX_RETRIES) {
                blk_mq_requeue_request(req, true);
        } else {
                if (mmc_card_removed(mq->card))
                        req->rq_flags |= RQF_QUIET;
                blk_mq_end_request(req, BLK_STS_IOERR);
        }
}

static bool mmc_blk_urgent_bkops_needed(struct mmc_queue *mq,
                                        struct mmc_queue_req *mqrq)
{
        return mmc_card_mmc(mq->card) && !mmc_host_is_spi(mq->card->host) &&
               (mqrq->brq.cmd.resp[0] & R1_EXCEPTION_EVENT ||
                mqrq->brq.stop.resp[0] & R1_EXCEPTION_EVENT);
}

static void mmc_blk_urgent_bkops(struct mmc_queue *mq,
                                 struct mmc_queue_req *mqrq)
{
        if (mmc_blk_urgent_bkops_needed(mq, mqrq))
                mmc_run_bkops(mq->card);
}

static void mmc_blk_hsq_req_done(struct mmc_request *mrq)
{
        struct mmc_queue_req *mqrq =
                container_of(mrq, struct mmc_queue_req, brq.mrq);
        struct request *req = mmc_queue_req_to_req(mqrq);
        struct request_queue *q = req->q;
        struct mmc_queue *mq = q->queuedata;
        struct mmc_host *host = mq->card->host;
        unsigned long flags;

        if (mmc_blk_rq_error(&mqrq->brq) ||
            mmc_blk_urgent_bkops_needed(mq, mqrq)) {
                spin_lock_irqsave(&mq->lock, flags);
                mq->recovery_needed = true;
                mq->recovery_req = req;
                spin_unlock_irqrestore(&mq->lock, flags);

                host->cqe_ops->cqe_recovery_start(host);

                schedule_work(&mq->recovery_work);
                return;
        }

        mmc_blk_rw_reset_success(mq, req);

        /*
         * Block layer timeouts race with completions which means the normal
         * completion path cannot be used during recovery.
         */
        if (mq->in_recovery)
                mmc_blk_cqe_complete_rq(mq, req);
        else
                blk_mq_complete_request(req);
}

void mmc_blk_mq_complete(struct request *req)
{
        struct mmc_queue *mq = req->q->queuedata;

        if (mq->use_cqe)
                mmc_blk_cqe_complete_rq(mq, req);
        else
                mmc_blk_mq_complete_rq(mq, req);
}

static void mmc_blk_mq_poll_completion(struct mmc_queue *mq,
                                       struct request *req)
{
        struct mmc_queue_req *mqrq = req_to_mmc_queue_req(req);
        struct mmc_host *host = mq->card->host;

        if (mmc_blk_rq_error(&mqrq->brq) ||
            mmc_blk_card_busy(mq->card, req)) {
                mmc_blk_mq_rw_recovery(mq, req);
        } else {
                mmc_blk_rw_reset_success(mq, req);
                mmc_retune_release(host);
        }

        mmc_blk_urgent_bkops(mq, mqrq);
}

static void mmc_blk_mq_dec_in_flight(struct mmc_queue *mq, struct request *req)
{
        unsigned long flags;
        bool put_card;

        spin_lock_irqsave(&mq->lock, flags);

        mq->in_flight[mmc_issue_type(mq, req)] -= 1;

        put_card = (mmc_tot_in_flight(mq) == 0);

        spin_unlock_irqrestore(&mq->lock, flags);

        if (put_card)
                mmc_put_card(mq->card, &mq->ctx);
}

static void mmc_blk_mq_post_req(struct mmc_queue *mq, struct request *req)
{
        struct mmc_queue_req *mqrq = req_to_mmc_queue_req(req);
        struct mmc_request *mrq = &mqrq->brq.mrq;
        struct mmc_host *host = mq->card->host;

        mmc_post_req(host, mrq, 0);

        /*
         * Block layer timeouts race with completions which means the normal
         * completion path cannot be used during recovery.
         */
        if (mq->in_recovery)
                mmc_blk_mq_complete_rq(mq, req);
        else
                blk_mq_complete_request(req);

        mmc_blk_mq_dec_in_flight(mq, req);
}

void mmc_blk_mq_recovery(struct mmc_queue *mq)
{
        struct request *req = mq->recovery_req;
        struct mmc_host *host = mq->card->host;
        struct mmc_queue_req *mqrq = req_to_mmc_queue_req(req);

        mq->recovery_req = NULL;
        mq->rw_wait = false;

        if (mmc_blk_rq_error(&mqrq->brq)) {
                mmc_retune_hold_now(host);
                mmc_blk_mq_rw_recovery(mq, req);
        }

        mmc_blk_urgent_bkops(mq, mqrq);

        mmc_blk_mq_post_req(mq, req);
}

static void mmc_blk_mq_complete_prev_req(struct mmc_queue *mq,
                                         struct request **prev_req)
{
        if (mmc_host_done_complete(mq->card->host))
                return;

        mutex_lock(&mq->complete_lock);

        if (!mq->complete_req)
                goto out_unlock;

        mmc_blk_mq_poll_completion(mq, mq->complete_req);

        if (prev_req)
                *prev_req = mq->complete_req;
        else
                mmc_blk_mq_post_req(mq, mq->complete_req);

        mq->complete_req = NULL;

out_unlock:
        mutex_unlock(&mq->complete_lock);
}

void mmc_blk_mq_complete_work(struct work_struct *work)
{
        struct mmc_queue *mq = container_of(work, struct mmc_queue,
                                            complete_work);

        mmc_blk_mq_complete_prev_req(mq, NULL);
}

static void mmc_blk_mq_req_done(struct mmc_request *mrq)
{
        struct mmc_queue_req *mqrq = container_of(mrq, struct mmc_queue_req,
                                                  brq.mrq);
        struct request *req = mmc_queue_req_to_req(mqrq);
        struct request_queue *q = req->q;
        struct mmc_queue *mq = q->queuedata;
        struct mmc_host *host = mq->card->host;
        unsigned long flags;

        if (!mmc_host_done_complete(host)) {
                bool waiting;

                /*
                 * We cannot complete the request in this context, so record
                 * that there is a request to complete, and that a following
                 * request does not need to wait (although it does need to
                 * complete complete_req first).
                 */
                spin_lock_irqsave(&mq->lock, flags);
                mq->complete_req = req;
                mq->rw_wait = false;
                waiting = mq->waiting;
                spin_unlock_irqrestore(&mq->lock, flags);

                /*
                 * If 'waiting' then the waiting task will complete this
                 * request, otherwise queue a work to do it. Note that
                 * complete_work may still race with the dispatch of a following
                 * request.
                 */
                if (waiting)
                        wake_up(&mq->wait);
                else
                        queue_work(mq->card->complete_wq, &mq->complete_work);

                return;
        }

        /* Take the recovery path for errors or urgent background operations */
        if (mmc_blk_rq_error(&mqrq->brq) ||
            mmc_blk_urgent_bkops_needed(mq, mqrq)) {
                spin_lock_irqsave(&mq->lock, flags);
                mq->recovery_needed = true;
                mq->recovery_req = req;
                spin_unlock_irqrestore(&mq->lock, flags);
                wake_up(&mq->wait);
                schedule_work(&mq->recovery_work);
                return;
        }

        mmc_blk_rw_reset_success(mq, req);

        mq->rw_wait = false;
        wake_up(&mq->wait);

        mmc_blk_mq_post_req(mq, req);
}

static bool mmc_blk_rw_wait_cond(struct mmc_queue *mq, int *err)
{
        unsigned long flags;
        bool done;

        /*
         * Wait while there is another request in progress, but not if recovery
         * is needed. Also indicate whether there is a request waiting to start.
         */
        spin_lock_irqsave(&mq->lock, flags);
        if (mq->recovery_needed) {
                *err = -EBUSY;
                done = true;
        } else {
                done = !mq->rw_wait;
        }
        mq->waiting = !done;
        spin_unlock_irqrestore(&mq->lock, flags);

        return done;
}

static int mmc_blk_rw_wait(struct mmc_queue *mq, struct request **prev_req)
{
        int err = 0;

        wait_event(mq->wait, mmc_blk_rw_wait_cond(mq, &err));

        /* Always complete the previous request if there is one */
        mmc_blk_mq_complete_prev_req(mq, prev_req);

        return err;
}

static int mmc_blk_mq_issue_rw_rq(struct mmc_queue *mq,
                                  struct request *req)
{
        struct mmc_queue_req *mqrq = req_to_mmc_queue_req(req);
        struct mmc_host *host = mq->card->host;
        struct request *prev_req = NULL;
        int err = 0;

        mmc_blk_rw_rq_prep(mqrq, mq->card, 0, mq);

        mqrq->brq.mrq.done = mmc_blk_mq_req_done;

        mmc_pre_req(host, &mqrq->brq.mrq);

        err = mmc_blk_rw_wait(mq, &prev_req);
        if (err)
                goto out_post_req;

        mq->rw_wait = true;

        err = mmc_start_request(host, &mqrq->brq.mrq);

        if (prev_req)
                mmc_blk_mq_post_req(mq, prev_req);

        if (err)
                mq->rw_wait = false;

        /* Release re-tuning here where there is no synchronization required */
        if (err || mmc_host_done_complete(host))
                mmc_retune_release(host);

out_post_req:
        if (err)
                mmc_post_req(host, &mqrq->brq.mrq, err);

        return err;
}

static int mmc_blk_wait_for_idle(struct mmc_queue *mq, struct mmc_host *host)
{
        if (mq->use_cqe)
                return host->cqe_ops->cqe_wait_for_idle(host);

        return mmc_blk_rw_wait(mq, NULL);
}

enum mmc_issued mmc_blk_mq_issue_rq(struct mmc_queue *mq, struct request *req)
{
        struct mmc_blk_data *md = mq->blkdata;
        struct mmc_card *card = md->queue.card;
        struct mmc_host *host = card->host;
        int ret;

        ret = mmc_blk_part_switch(card, md->part_type);
        if (ret)
                return MMC_REQ_FAILED_TO_START;

        switch (mmc_issue_type(mq, req)) {
        case MMC_ISSUE_SYNC:
                ret = mmc_blk_wait_for_idle(mq, host);
                if (ret)
                        return MMC_REQ_BUSY;
                switch (req_op(req)) {
                case REQ_OP_DRV_IN:
                case REQ_OP_DRV_OUT:
                        mmc_blk_issue_drv_op(mq, req);
                        break;
                case REQ_OP_DISCARD:
                        mmc_blk_issue_discard_rq(mq, req);
                        break;
                case REQ_OP_SECURE_ERASE:
                        mmc_blk_issue_secdiscard_rq(mq, req);
                        break;
                case REQ_OP_FLUSH:
                        mmc_blk_issue_flush(mq, req);
                        break;
                default:
                        WARN_ON_ONCE(1);
                        return MMC_REQ_FAILED_TO_START;
                }
                return MMC_REQ_FINISHED;
        case MMC_ISSUE_DCMD:
        case MMC_ISSUE_ASYNC:
                switch (req_op(req)) {
                case REQ_OP_FLUSH:
                        ret = mmc_blk_cqe_issue_flush(mq, req);
                        break;
                case REQ_OP_READ:
                case REQ_OP_WRITE:
                        if (mq->use_cqe)
                                ret = mmc_blk_cqe_issue_rw_rq(mq, req);
                        else
                                ret = mmc_blk_mq_issue_rw_rq(mq, req);
                        break;
                default:
                        WARN_ON_ONCE(1);
                        ret = -EINVAL;
                }
                if (!ret)
                        return MMC_REQ_STARTED;
                return ret == -EBUSY ? MMC_REQ_BUSY : MMC_REQ_FAILED_TO_START;
        default:
                WARN_ON_ONCE(1);
                return MMC_REQ_FAILED_TO_START;
        }
}

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,
                                              int area_type)
{
        struct mmc_blk_data *md;
        int devidx, ret;

        devidx = ida_simple_get(&mmc_blk_ida, 0, max_devices, GFP_KERNEL);
        if (devidx < 0) {
                /*
                 * We get -ENOSPC because there are no more any available
                 * devidx. The reason may be that, either userspace haven't yet
                 * unmounted the partitions, which postpones mmc_blk_release()
                 * from being called, or the device has more partitions than
                 * what we support.
                 */
                if (devidx == -ENOSPC)
                        dev_err(mmc_dev(card->host),
                                "no more device IDs available\n");

                return ERR_PTR(devidx);
        }

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

        md->area_type = area_type;

        /*
         * 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;
        }

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

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

        md->queue.blkdata = md;

        /*
         * Keep an extra reference to the queue so that we can shutdown the
         * queue (i.e. call blk_cleanup_queue()) while there are still
         * references to the 'md'. The corresponding blk_put_queue() is in
         * mmc_blk_put().
         */
        if (!blk_get_queue(md->queue.queue)) {
                mmc_cleanup_queue(&md->queue);
                ret = -ENODEV;
                goto err_putdisk;
        }

        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->parent = parent;
        set_disk_ro(md->disk, md->read_only || default_ro);
        md->disk->flags = GENHD_FL_EXT_DEVT;
        if (area_type & (MMC_BLK_DATA_AREA_RPMB | MMC_BLK_DATA_AREA_BOOT))
                md->disk->flags |= GENHD_FL_NO_PART_SCAN
                                   | GENHD_FL_SUPPRESS_PARTITION_INFO;

        /*
         * 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%u%s", card->host->index, subname ? subname : "");

        set_capacity(md->disk, size);

        if (mmc_host_cmd23(card->host)) {
                if ((mmc_card_mmc(card) &&
                     card->csd.mmca_vsn >= CSD_SPEC_VER_3) ||
                    (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_write_cache(md->queue.queue, true, true);
        }

        return md;

 err_putdisk:
        put_disk(md->disk);
 err_kfree:
        kfree(md);
 out:
        ida_simple_remove(&mmc_blk_ida, devidx);
        return ERR_PTR(ret);
}

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

        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 = (typeof(sector_t))card->csd.capacity
                        << (card->csd.read_blkbits - 9);
        }

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

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,
                              int area_type)
{
        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, area_type);
        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), 512, STRING_UNITS_2,
                        cap_str, sizeof(cap_str));
        pr_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;
}

/**
 * mmc_rpmb_ioctl() - ioctl handler for the RPMB chardev
 * @filp: the character device file
 * @cmd: the ioctl() command
 * @arg: the argument from userspace
 *
 * This will essentially just redirect the ioctl()s coming in over to
 * the main block device spawning the RPMB character device.
 */
static long mmc_rpmb_ioctl(struct file *filp, unsigned int cmd,
                           unsigned long arg)
{
        struct mmc_rpmb_data *rpmb = filp->private_data;
        int ret;

        switch (cmd) {
        case MMC_IOC_CMD:
                ret = mmc_blk_ioctl_cmd(rpmb->md,
                                        (struct mmc_ioc_cmd __user *)arg,
                                        rpmb);
                break;
        case MMC_IOC_MULTI_CMD:
                ret = mmc_blk_ioctl_multi_cmd(rpmb->md,
                                        (struct mmc_ioc_multi_cmd __user *)arg,
                                        rpmb);
                break;
        default:
                ret = -EINVAL;
                break;
        }

        return ret;
}

#ifdef CONFIG_COMPAT
static long mmc_rpmb_ioctl_compat(struct file *filp, unsigned int cmd,
                              unsigned long arg)
{
        return mmc_rpmb_ioctl(filp, cmd, (unsigned long)compat_ptr(arg));
}
#endif

static int mmc_rpmb_chrdev_open(struct inode *inode, struct file *filp)
{
        struct mmc_rpmb_data *rpmb = container_of(inode->i_cdev,
                                                  struct mmc_rpmb_data, chrdev);

        get_device(&rpmb->dev);
        filp->private_data = rpmb;
        mmc_blk_get(rpmb->md->disk);

        return nonseekable_open(inode, filp);
}

static int mmc_rpmb_chrdev_release(struct inode *inode, struct file *filp)
{
        struct mmc_rpmb_data *rpmb = container_of(inode->i_cdev,
                                                  struct mmc_rpmb_data, chrdev);

        put_device(&rpmb->dev);
        mmc_blk_put(rpmb->md);

        return 0;
}

static const struct file_operations mmc_rpmb_fileops = {
        .release = mmc_rpmb_chrdev_release,
        .open = mmc_rpmb_chrdev_open,
        .owner = THIS_MODULE,
        .llseek = no_llseek,
        .unlocked_ioctl = mmc_rpmb_ioctl,
#ifdef CONFIG_COMPAT
        .compat_ioctl = mmc_rpmb_ioctl_compat,
#endif
};

static void mmc_blk_rpmb_device_release(struct device *dev)
{
        struct mmc_rpmb_data *rpmb = dev_get_drvdata(dev);

        ida_simple_remove(&mmc_rpmb_ida, rpmb->id);
        kfree(rpmb);
}

static int mmc_blk_alloc_rpmb_part(struct mmc_card *card,
                                   struct mmc_blk_data *md,
                                   unsigned int part_index,
                                   sector_t size,
                                   const char *subname)
{
        int devidx, ret;
        char rpmb_name[DISK_NAME_LEN];
        char cap_str[10];
        struct mmc_rpmb_data *rpmb;

        /* This creates the minor number for the RPMB char device */
        devidx = ida_simple_get(&mmc_rpmb_ida, 0, max_devices, GFP_KERNEL);
        if (devidx < 0)
                return devidx;

        rpmb = kzalloc(sizeof(*rpmb), GFP_KERNEL);
        if (!rpmb) {
                ida_simple_remove(&mmc_rpmb_ida, devidx);
                return -ENOMEM;
        }

        snprintf(rpmb_name, sizeof(rpmb_name),
                 "mmcblk%u%s", card->host->index, subname ? subname : "");

        rpmb->id = devidx;
        rpmb->part_index = part_index;
        rpmb->dev.init_name = rpmb_name;
        rpmb->dev.bus = &mmc_rpmb_bus_type;
        rpmb->dev.devt = MKDEV(MAJOR(mmc_rpmb_devt), rpmb->id);
        rpmb->dev.parent = &card->dev;
        rpmb->dev.release = mmc_blk_rpmb_device_release;
        device_initialize(&rpmb->dev);
        dev_set_drvdata(&rpmb->dev, rpmb);
        rpmb->md = md;

        cdev_init(&rpmb->chrdev, &mmc_rpmb_fileops);
        rpmb->chrdev.owner = THIS_MODULE;
        ret = cdev_device_add(&rpmb->chrdev, &rpmb->dev);
        if (ret) {
                pr_err("%s: could not add character device\n", rpmb_name);
                goto out_put_device;
        }

        list_add(&rpmb->node, &md->rpmbs);

        string_get_size((u64)size, 512, STRING_UNITS_2,
                        cap_str, sizeof(cap_str));

        pr_info("%s: %s %s partition %u %s, chardev (%d:%d)\n",
                rpmb_name, mmc_card_id(card),
                mmc_card_name(card), EXT_CSD_PART_CONFIG_ACC_RPMB, cap_str,
                MAJOR(mmc_rpmb_devt), rpmb->id);

        return 0;

out_put_device:
        put_device(&rpmb->dev);
        return ret;
}

static void mmc_blk_remove_rpmb_part(struct mmc_rpmb_data *rpmb)

{
        cdev_device_del(&rpmb->chrdev, &rpmb->dev);
        put_device(&rpmb->dev);
}

/* MMC Physical partitions consist of two boot partitions and
 * up to four general purpose partitions.
 * For each partition enabled in EXT_CSD a block device will be allocatedi
 * to provide access to the partition.
 */

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

        if (!mmc_card_mmc(card))
                return 0;

        for (idx = 0; idx < card->nr_parts; idx++) {
                if (card->part[idx].area_type & MMC_BLK_DATA_AREA_RPMB) {
                        /*
                         * RPMB partitions does not provide block access, they
                         * are only accessed using ioctl():s. Thus create
                         * special RPMB block devices that do not have a
                         * backing block queue for these.
                         */
                        ret = mmc_blk_alloc_rpmb_part(card, md,
                                card->part[idx].part_cfg,
                                card->part[idx].size >> 9,
                                card->part[idx].name);
                        if (ret)
                                return ret;
                } else if (card->part[idx].size) {
                        ret = mmc_blk_alloc_part(card, md,
                                card->part[idx].part_cfg,
                                card->part[idx].size >> 9,
                                card->part[idx].force_ro,
                                card->part[idx].name,
                                card->part[idx].area_type);
                        if (ret)
                                return ret;
                }
        }

        return 0;
}

static void mmc_blk_remove_req(struct mmc_blk_data *md)
{
        struct mmc_card *card;

        if (md) {
                /*
                 * Flush remaining requests and free queues. It
                 * is freeing the queue that stops new requests
                 * from being accepted.
                 */
                card = md->queue.card;
                if (md->disk->flags & GENHD_FL_UP) {
                        device_remove_file(disk_to_dev(md->disk), &md->force_ro);
                        if ((md->area_type & MMC_BLK_DATA_AREA_BOOT) &&
                                        card->ext_csd.boot_ro_lockable)
                                device_remove_file(disk_to_dev(md->disk),
                                        &md->power_ro_lock);

                        del_gendisk(md->disk);
                }
                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;
        struct mmc_rpmb_data *rpmb;

        /* Remove RPMB partitions */
        list_for_each_safe(pos, q, &md->rpmbs) {
                rpmb = list_entry(pos, struct mmc_rpmb_data, node);
                list_del(pos);
                mmc_blk_remove_rpmb_part(rpmb);
        }
        /* Remove block partitions */
        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;
        struct mmc_card *card = md->queue.card;

        device_add_disk(md->parent, md->disk, NULL);
        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)
                goto force_ro_fail;

        if ((md->area_type & MMC_BLK_DATA_AREA_BOOT) &&
             card->ext_csd.boot_ro_lockable) {
                umode_t mode;

                if (card->ext_csd.boot_ro_lock & EXT_CSD_BOOT_WP_B_PWR_WP_DIS)
                        mode = S_IRUGO;
                else
                        mode = S_IRUGO | S_IWUSR;

                md->power_ro_lock.show = power_ro_lock_show;
                md->power_ro_lock.store = power_ro_lock_store;
                sysfs_attr_init(&md->power_ro_lock.attr);
                md->power_ro_lock.attr.mode = mode;
                md->power_ro_lock.attr.name =
                                        "ro_lock_until_next_power_on";
                ret = device_create_file(disk_to_dev(md->disk),
                                &md->power_ro_lock);
                if (ret)
                        goto power_ro_lock_fail;
        }
        return ret;

power_ro_lock_fail:
        device_remove_file(disk_to_dev(md->disk), &md->force_ro);
force_ro_fail:
        del_gendisk(md->disk);

        return ret;
}

#ifdef CONFIG_DEBUG_FS

static int mmc_dbg_card_status_get(void *data, u64 *val)
{
        struct mmc_card *card = data;
        struct mmc_blk_data *md = dev_get_drvdata(&card->dev);
        struct mmc_queue *mq = &md->queue;
        struct request *req;
        int ret;

        /* Ask the block layer about the card status */
        req = blk_get_request(mq->queue, REQ_OP_DRV_IN, 0);
        if (IS_ERR(req))
                return PTR_ERR(req);
        req_to_mmc_queue_req(req)->drv_op = MMC_DRV_OP_GET_CARD_STATUS;
        blk_execute_rq(mq->queue, NULL, req, 0);
        ret = req_to_mmc_queue_req(req)->drv_op_result;
        if (ret >= 0) {
                *val = ret;
                ret = 0;
        }
        blk_put_request(req);

        return ret;
}
DEFINE_DEBUGFS_ATTRIBUTE(mmc_dbg_card_status_fops, mmc_dbg_card_status_get,
                         NULL, "%08llx\n");

/* That is two digits * 512 + 1 for newline */
#define EXT_CSD_STR_LEN 1025

static int mmc_ext_csd_open(struct inode *inode, struct file *filp)
{
        struct mmc_card *card = inode->i_private;
        struct mmc_blk_data *md = dev_get_drvdata(&card->dev);
        struct mmc_queue *mq = &md->queue;
        struct request *req;
        char *buf;
        ssize_t n = 0;
        u8 *ext_csd;
        int err, i;

        buf = kmalloc(EXT_CSD_STR_LEN + 1, GFP_KERNEL);
        if (!buf)
                return -ENOMEM;

        /* Ask the block layer for the EXT CSD */
        req = blk_get_request(mq->queue, REQ_OP_DRV_IN, 0);
        if (IS_ERR(req)) {
                err = PTR_ERR(req);
                goto out_free;
        }
        req_to_mmc_queue_req(req)->drv_op = MMC_DRV_OP_GET_EXT_CSD;
        req_to_mmc_queue_req(req)->drv_op_data = &ext_csd;
        blk_execute_rq(mq->queue, NULL, req, 0);
        err = req_to_mmc_queue_req(req)->drv_op_result;
        blk_put_request(req);
        if (err) {
                pr_err("FAILED %d\n", err);
                goto out_free;
        }

        for (i = 0; i < 512; i++)
                n += sprintf(buf + n, "%02x", ext_csd[i]);
        n += sprintf(buf + n, "\n");

        if (n != EXT_CSD_STR_LEN) {
                err = -EINVAL;
                kfree(ext_csd);
                goto out_free;
        }

        filp->private_data = buf;
        kfree(ext_csd);
        return 0;

out_free:
        kfree(buf);
        return err;
}

static ssize_t mmc_ext_csd_read(struct file *filp, char __user *ubuf,
                                size_t cnt, loff_t *ppos)
{
        char *buf = filp->private_data;

        return simple_read_from_buffer(ubuf, cnt, ppos,
                                       buf, EXT_CSD_STR_LEN);
}

static int mmc_ext_csd_release(struct inode *inode, struct file *file)
{
        kfree(file->private_data);
        return 0;
}

static const struct file_operations mmc_dbg_ext_csd_fops = {
        .open           = mmc_ext_csd_open,
        .read           = mmc_ext_csd_read,
        .release        = mmc_ext_csd_release,
        .llseek         = default_llseek,
};

static int mmc_blk_add_debugfs(struct mmc_card *card, struct mmc_blk_data *md)
{
        struct dentry *root;

        if (!card->debugfs_root)
                return 0;

        root = card->debugfs_root;

        if (mmc_card_mmc(card) || mmc_card_sd(card)) {
                md->status_dentry =
                        debugfs_create_file_unsafe("status", 0400, root,
                                                   card,
                                                   &mmc_dbg_card_status_fops);
                if (!md->status_dentry)
                        return -EIO;
        }

        if (mmc_card_mmc(card)) {
                md->ext_csd_dentry =
                        debugfs_create_file("ext_csd", S_IRUSR, root, card,
                                            &mmc_dbg_ext_csd_fops);
                if (!md->ext_csd_dentry)
                        return -EIO;
        }

        return 0;
}

static void mmc_blk_remove_debugfs(struct mmc_card *card,
                                   struct mmc_blk_data *md)
{
        if (!card->debugfs_root)
                return;

        if (!IS_ERR_OR_NULL(md->status_dentry)) {
                debugfs_remove(md->status_dentry);
                md->status_dentry = NULL;
        }

        if (!IS_ERR_OR_NULL(md->ext_csd_dentry)) {
                debugfs_remove(md->ext_csd_dentry);
                md->ext_csd_dentry = NULL;
        }
}

#else

static int mmc_blk_add_debugfs(struct mmc_card *card, struct mmc_blk_data *md)
{
        return 0;
}

static void mmc_blk_remove_debugfs(struct mmc_card *card,
                                   struct mmc_blk_data *md)
{
}

#endif /* CONFIG_DEBUG_FS */

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

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

        mmc_fixup_device(card, mmc_blk_fixups);

        card->complete_wq = alloc_workqueue("mmc_complete",
                                        WQ_MEM_RECLAIM | WQ_HIGHPRI, 0);
        if (unlikely(!card->complete_wq)) {
                pr_err("Failed to create mmc completion workqueue");
                return -ENOMEM;
        }

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

        string_get_size((u64)get_capacity(md->disk), 512, STRING_UNITS_2,
                        cap_str, sizeof(cap_str));
        pr_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;

        dev_set_drvdata(&card->dev, md);

        if (mmc_add_disk(md))
                goto out;

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

        /* Add two debugfs entries */
        mmc_blk_add_debugfs(card, md);

        pm_runtime_set_autosuspend_delay(&card->dev, 3000);
        pm_runtime_use_autosuspend(&card->dev);

        /*
         * Don't enable runtime PM for SD-combo cards here. Leave that
         * decision to be taken during the SDIO init sequence instead.
         */
        if (card->type != MMC_TYPE_SD_COMBO) {
                pm_runtime_set_active(&card->dev);
                pm_runtime_enable(&card->dev);
        }

        return 0;

 out:
        mmc_blk_remove_parts(card, md);
        mmc_blk_remove_req(md);
        return 0;
}

static void mmc_blk_remove(struct mmc_card *card)
{
        struct mmc_blk_data *md = dev_get_drvdata(&card->dev);

        mmc_blk_remove_debugfs(card, md);
        mmc_blk_remove_parts(card, md);
        pm_runtime_get_sync(&card->dev);
        if (md->part_curr != md->part_type) {
                mmc_claim_host(card->host);
                mmc_blk_part_switch(card, md->part_type);
                mmc_release_host(card->host);
        }
        if (card->type != MMC_TYPE_SD_COMBO)
                pm_runtime_disable(&card->dev);
        pm_runtime_put_noidle(&card->dev);
        mmc_blk_remove_req(md);
        dev_set_drvdata(&card->dev, NULL);
        destroy_workqueue(card->complete_wq);
}

static int _mmc_blk_suspend(struct mmc_card *card)
{
        struct mmc_blk_data *part_md;
        struct mmc_blk_data *md = dev_get_drvdata(&card->dev);

        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 void mmc_blk_shutdown(struct mmc_card *card)
{
        _mmc_blk_suspend(card);
}

#ifdef CONFIG_PM_SLEEP
static int mmc_blk_suspend(struct device *dev)
{
        struct mmc_card *card = mmc_dev_to_card(dev);

        return _mmc_blk_suspend(card);
}

static int mmc_blk_resume(struct device *dev)
{
        struct mmc_blk_data *part_md;
        struct mmc_blk_data *md = dev_get_drvdata(dev);

        if (md) {
                /*
                 * 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;
}
#endif

static SIMPLE_DEV_PM_OPS(mmc_blk_pm_ops, mmc_blk_suspend, mmc_blk_resume);

static struct mmc_driver mmc_driver = {
        .drv            = {
                .name   = "mmcblk",
                .pm     = &mmc_blk_pm_ops,
        },
        .probe          = mmc_blk_probe,
        .remove         = mmc_blk_remove,
        .shutdown       = mmc_blk_shutdown,
};

static int __init mmc_blk_init(void)
{
        int res;

        res  = bus_register(&mmc_rpmb_bus_type);
        if (res < 0) {
                pr_err("mmcblk: could not register RPMB bus type\n");
                return res;
        }
        res = alloc_chrdev_region(&mmc_rpmb_devt, 0, MAX_DEVICES, "rpmb");
        if (res < 0) {
                pr_err("mmcblk: failed to allocate rpmb chrdev region\n");
                goto out_bus_unreg;
        }

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

        max_devices = min(MAX_DEVICES, (1 << MINORBITS) / perdev_minors);

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

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

        return 0;

out_blkdev_unreg:
        unregister_blkdev(MMC_BLOCK_MAJOR, "mmc");
out_chrdev_unreg:
        unregister_chrdev_region(mmc_rpmb_devt, MAX_DEVICES);
out_bus_unreg:
        bus_unregister(&mmc_rpmb_bus_type);
        return res;
}

static void __exit mmc_blk_exit(void)
{
        mmc_unregister_driver(&mmc_driver);
        unregister_blkdev(MMC_BLOCK_MAJOR, "mmc");
        unregister_chrdev_region(mmc_rpmb_devt, MAX_DEVICES);
        bus_unregister(&mmc_rpmb_bus_type);
}

module_init(mmc_blk_init);
module_exit(mmc_blk_exit);

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