/*
 * Block driver for media (i.e., flash cards)
 *
 * Copyright 2002 Hewlett-Packard Company
 * Copyright 2005-2008 Pierre Ossman
 *
 * Use consistent with the GNU GPL is permitted,
 * provided that this copyright notice is
 * preserved in its entirety in all copies and derived works.
 *
 * HEWLETT-PACKARD COMPANY MAKES NO WARRANTIES, EXPRESSED OR IMPLIED,
 * AS TO THE USEFULNESS OR CORRECTNESS OF THIS CODE OR ITS
 * FITNESS FOR ANY PARTICULAR PURPOSE.
 *
 * Many thanks to Alessandro Rubini and Jonathan Corbet!
 *
 * Author:  Andrew Christian
 *          28 May 2002
 */
#include <linux/moduleparam.h>
#include <linux/module.h>
#include <linux/init.h>

#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/hdreg.h>
#include <linux/kdev_t.h>
#include <linux/blkdev.h>
#include <linux/mutex.h>
#include <linux/scatterlist.h>
#include <linux/string_helpers.h>

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

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

#include "queue.h"

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

static DEFINE_MUTEX(block_mutex);

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

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

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

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

        unsigned int    usage;
        unsigned int    read_only;
};

static DEFINE_MUTEX(open_lock);

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

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

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

        return md;
}

static void mmc_blk_put(struct mmc_blk_data *md)
{
        mutex_lock(&open_lock);
        md->usage--;
        if (md->usage == 0) {
                int devmaj = MAJOR(disk_devt(md->disk));
                int devidx = MINOR(disk_devt(md->disk)) / perdev_minors;

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

                blk_cleanup_queue(md->queue.queue);

                __clear_bit(devidx, dev_use);

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

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

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

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

        return ret;
}

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

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

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

static const struct block_device_operations mmc_bdops = {
        .open                   = mmc_blk_open,
        .release                = mmc_blk_release,
        .getgeo                 = mmc_blk_getgeo,
        .owner                  = THIS_MODULE,
};

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

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

        struct mmc_request mrq;
        struct mmc_command cmd;
        struct mmc_data data;
        unsigned int timeout_us;

        struct scatterlist sg;

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

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

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

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

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

        memset(&data, 0, sizeof(struct mmc_data));

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

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

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

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

        memset(&mrq, 0, sizeof(struct mmc_request));

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

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

        sg_init_one(&sg, blocks, 4);

        mmc_wait_for_req(card->host, &mrq);

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

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

        return result;
}

static u32 get_card_status(struct mmc_card *card, struct request *req)
{
        struct mmc_command cmd;
        int err;

        memset(&cmd, 0, sizeof(struct mmc_command));
        cmd.opcode = MMC_SEND_STATUS;
        if (!mmc_host_is_spi(card->host))
                cmd.arg = card->rca << 16;
        cmd.flags = MMC_RSP_SPI_R2 | MMC_RSP_R1 | MMC_CMD_AC;
        err = mmc_wait_for_cmd(card->host, &cmd, 0);
        if (err)
                printk(KERN_ERR "%s: error %d sending status command",
                       req->rq_disk->disk_name, err);
        return cmd.resp[0];
}

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

        mmc_claim_host(card->host);

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

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

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

        err = mmc_erase(card, from, nr, arg);
out:
        spin_lock_irq(&md->lock);
        __blk_end_request(req, err, blk_rq_bytes(req));
        spin_unlock_irq(&md->lock);

        mmc_release_host(card->host);

        return err ? 0 : 1;
}

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

        mmc_claim_host(card->host);

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

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

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

        err = mmc_erase(card, from, nr, arg);
        if (!err && arg == MMC_SECURE_TRIM1_ARG)
                err = mmc_erase(card, from, nr, MMC_SECURE_TRIM2_ARG);
out:
        spin_lock_irq(&md->lock);
        __blk_end_request(req, err, blk_rq_bytes(req));
        spin_unlock_irq(&md->lock);

        mmc_release_host(card->host);

        return err ? 0 : 1;
}

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

        mmc_claim_host(card->host);

        do {
                struct mmc_command cmd;
                u32 readcmd, writecmd, status = 0;

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

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

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

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

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

                mmc_set_data_timeout(&brq.data, card);

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

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

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

                mmc_queue_bounce_pre(mq);

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

                mmc_queue_bounce_post(mq);

                /*
                 * Check for errors here, but don't jump to cmd_err
                 * until later as we need to wait for the card to leave
                 * programming mode even when things go wrong.
                 */
                if (brq.cmd.error || brq.data.error || brq.stop.error) {
                        if (brq.data.blocks > 1 && rq_data_dir(req) == READ) {
                                /* Redo read one sector at a time */
                                printk(KERN_WARNING "%s: retrying using single "
                                       "block read\n", req->rq_disk->disk_name);
                                disable_multi = 1;
                                continue;
                        }
                        status = get_card_status(card, req);
                }

                if (brq.cmd.error) {
                        printk(KERN_ERR "%s: error %d sending read/write "
                               "command, response %#x, card status %#x\n",
                               req->rq_disk->disk_name, brq.cmd.error,
                               brq.cmd.resp[0], status);
                }

                if (brq.data.error) {
                        if (brq.data.error == -ETIMEDOUT && brq.mrq.stop)
                                /* 'Stop' response contains card status */
                                status = brq.mrq.stop->resp[0];
                        printk(KERN_ERR "%s: error %d transferring data,"
                               " sector %u, nr %u, card status %#x\n",
                               req->rq_disk->disk_name, brq.data.error,
                               (unsigned)blk_rq_pos(req),
                               (unsigned)blk_rq_sectors(req), status);
                }

                if (brq.stop.error) {
                        printk(KERN_ERR "%s: error %d sending stop command, "
                               "response %#x, card status %#x\n",
                               req->rq_disk->disk_name, brq.stop.error,
                               brq.stop.resp[0], status);
                }

                if (!mmc_host_is_spi(card->host) && rq_data_dir(req) != READ) {
                        do {
                                int err;

                                cmd.opcode = MMC_SEND_STATUS;
                                cmd.arg = card->rca << 16;
                                cmd.flags = MMC_RSP_R1 | MMC_CMD_AC;
                                err = mmc_wait_for_cmd(card->host, &cmd, 5);
                                if (err) {
                                        printk(KERN_ERR "%s: error %d requesting status\n",
                                               req->rq_disk->disk_name, err);
                                        goto cmd_err;
                                }
                                /*
                                 * Some cards mishandle the status bits,
                                 * so make sure to check both the busy
                                 * indication and the card state.
                                 */
                        } while (!(cmd.resp[0] & R1_READY_FOR_DATA) ||
                                (R1_CURRENT_STATE(cmd.resp[0]) == 7));

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

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

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

        mmc_release_host(card->host);

        return 1;

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

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

        mmc_release_host(card->host);

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

        return 0;
}

static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
{
        if (req->cmd_flags & REQ_DISCARD) {
                if (req->cmd_flags & REQ_SECURE)
                        return mmc_blk_issue_secdiscard_rq(mq, req);
                else
                        return mmc_blk_issue_discard_rq(mq, req);
        } else {
                return mmc_blk_issue_rw_rq(mq, req);
        }
}

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

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

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


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

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

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

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

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

        md->disk->major = MMC_BLOCK_MAJOR;
        md->disk->first_minor = devidx * perdev_minors;
        md->disk->fops = &mmc_bdops;
        md->disk->private_data = md;
        md->disk->queue = md->queue.queue;
        md->disk->driverfs_dev = &card->dev;

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

        snprintf(md->disk->disk_name, sizeof(md->disk->disk_name),
                "mmcblk%d", devidx);

        blk_queue_logical_block_size(md->queue.queue, 512);

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

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

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

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

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

        return 0;
}

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

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

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

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

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

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

 out:
        mmc_cleanup_queue(&md->queue);
        mmc_blk_put(md);

        return err;
}

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

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

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

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

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

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

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

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

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

static int __init mmc_blk_init(void)
{
        int res;

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

        max_devices = 256 / perdev_minors;

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

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

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

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

module_init(mmc_blk_init);
module_exit(mmc_blk_exit);

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