core.c

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/*
 *  linux/drivers/mmc/core/core.c
 *
 *  Copyright (C) 2003-2004 Russell King, All Rights Reserved.
 *  SD support Copyright (C) 2004 Ian Molton, All Rights Reserved.
 *  Copyright (C) 2005-2008 Pierre Ossman, All Rights Reserved.
 *  MMCv4 support Copyright (C) 2006 Philip Langdale, All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/module.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/completion.h>
#include <linux/device.h>
#include <linux/delay.h>
#include <linux/pagemap.h>
#include <linux/err.h>
#include <linux/leds.h>
#include <linux/scatterlist.h>
#include <linux/log2.h>
#include <linux/regulator/consumer.h>
#include <linux/pm_runtime.h>
#include <linux/suspend.h>
#include <linux/fault-inject.h>
#include <linux/random.h>
#include <linux/slab.h>

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

#include "core.h"
#include "bus.h"
#include "host.h"
#include "sdio_bus.h"

#include "mmc_ops.h"
#include "sd_ops.h"
#include "sdio_ops.h"

/*
 * Background operations can take a long time, depending on the housekeeping
 * operations the card has to perform.
 */
#define MMC_BKOPS_MAX_TIMEOUT   (4 * 60 * 1000) /* max time to wait in ms */

static struct workqueue_struct *workqueue;
static const unsigned freqs[] = { 400000, 300000, 200000, 100000 };

/*
 * Enabling software CRCs on the data blocks can be a significant (30%)
 * performance cost, and for other reasons may not always be desired.
 * So we allow it it to be disabled.
 */
bool use_spi_crc = 1;
module_param(use_spi_crc, bool, 0);

/*
 * We normally treat cards as removed during suspend if they are not
 * known to be on a non-removable bus, to avoid the risk of writing
 * back data to a different card after resume.  Allow this to be
 * overridden if necessary.
 */
#ifdef CONFIG_MMC_UNSAFE_RESUME
bool mmc_assume_removable;
#else
bool mmc_assume_removable = 1;
#endif
EXPORT_SYMBOL(mmc_assume_removable);
module_param_named(removable, mmc_assume_removable, bool, 0644);
MODULE_PARM_DESC(
    removable,
    "MMC/SD cards are removable and may be removed during suspend");

/*
 * Internal function. Schedule delayed work in the MMC work queue.
 */
static int mmc_schedule_delayed_work(struct delayed_work *work,
                     unsigned long delay)
{
    return queue_delayed_work(workqueue, work, delay);
}

/*
 * Internal function. Flush all scheduled work from the MMC work queue.
 */
static void mmc_flush_scheduled_work(void)
{
    flush_workqueue(workqueue);
}

#ifdef CONFIG_FAIL_MMC_REQUEST

/*
 * Internal function. Inject random data errors.
 * If mmc_data is NULL no errors are injected.
 */
static void mmc_should_fail_request(struct mmc_host *host,
                    struct mmc_request *mrq)
{
    struct mmc_command *cmd = mrq->cmd;
    struct mmc_data *data = mrq->data;
    static const int data_errors[] = {
        -ETIMEDOUT,
        -EILSEQ,
        -EIO,
    };

    if (!data)
        return;

    if (cmd->error || data->error ||
        !should_fail(&host->fail_mmc_request, data->blksz * data->blocks))
        return;

    data->error = data_errors[random32() % ARRAY_SIZE(data_errors)];
    data->bytes_xfered = (random32() % (data->bytes_xfered >> 9)) << 9;
}

#else /* CONFIG_FAIL_MMC_REQUEST */

static inline void mmc_should_fail_request(struct mmc_host *host,
                       struct mmc_request *mrq)
{
}

#endif /* CONFIG_FAIL_MMC_REQUEST */

void mmc_request_done(struct mmc_host *host, struct mmc_request *mrq)
{
    struct mmc_command *cmd = mrq->cmd;
    int err = cmd->error;

    if (err && cmd->retries && mmc_host_is_spi(host)) {
        if (cmd->resp[0] & R1_SPI_ILLEGAL_COMMAND)
            cmd->retries = 0;
    }

    if (err && cmd->retries && !mmc_card_removed(host->card)) {
        /*
         * Request starter must handle retries - see
         * mmc_wait_for_req_done().
         */
        if (mrq->done)
            mrq->done(mrq);
    } else {
        mmc_should_fail_request(host, mrq);

        led_trigger_event(host->led, LED_OFF);

        pr_debug("%s: req done (CMD%u): %d: %08x %08x %08x %08x\n",
            mmc_hostname(host), cmd->opcode, err,
            cmd->resp[0], cmd->resp[1],
            cmd->resp[2], cmd->resp[3]);

        if (mrq->data) {
            pr_debug("%s:     %d bytes transferred: %d\n",
                mmc_hostname(host),
                mrq->data->bytes_xfered, mrq->data->error);
        }

        if (mrq->stop) {
            pr_debug("%s:     (CMD%u): %d: %08x %08x %08x %08x\n",
                mmc_hostname(host), mrq->stop->opcode,
                mrq->stop->error,
                mrq->stop->resp[0], mrq->stop->resp[1],
                mrq->stop->resp[2], mrq->stop->resp[3]);
        }

        if (mrq->done)
            mrq->done(mrq);

        mmc_host_clk_release(host);
    }
}

EXPORT_SYMBOL(mmc_request_done);

static void
mmc_start_request(struct mmc_host *host, struct mmc_request *mrq)
{
#ifdef CONFIG_MMC_DEBUG
    unsigned int i, sz;
    struct scatterlist *sg;
#endif

    if (mrq->sbc) {
        pr_debug("<%s: starting CMD%u arg %08x flags %08x>\n",
             mmc_hostname(host), mrq->sbc->opcode,
             mrq->sbc->arg, mrq->sbc->flags);
    }

    pr_debug("%s: starting CMD%u arg %08x flags %08x\n",
         mmc_hostname(host), mrq->cmd->opcode,
         mrq->cmd->arg, mrq->cmd->flags);

    if (mrq->data) {
        pr_debug("%s:     blksz %d blocks %d flags %08x "
            "tsac %d ms nsac %d\n",
            mmc_hostname(host), mrq->data->blksz,
            mrq->data->blocks, mrq->data->flags,
            mrq->data->timeout_ns / 1000000,
            mrq->data->timeout_clks);
    }

    if (mrq->stop) {
        pr_debug("%s:     CMD%u arg %08x flags %08x\n",
             mmc_hostname(host), mrq->stop->opcode,
             mrq->stop->arg, mrq->stop->flags);
    }

    WARN_ON(!host->claimed);

    mrq->cmd->error = 0;
    mrq->cmd->mrq = mrq;
    if (mrq->data) {
        BUG_ON(mrq->data->blksz > host->max_blk_size);
        BUG_ON(mrq->data->blocks > host->max_blk_count);
        BUG_ON(mrq->data->blocks * mrq->data->blksz >
            host->max_req_size);

#ifdef CONFIG_MMC_DEBUG
        sz = 0;
        for_each_sg(mrq->data->sg, sg, mrq->data->sg_len, i)
            sz += sg->length;
        BUG_ON(sz != mrq->data->blocks * mrq->data->blksz);
#endif

        mrq->cmd->data = mrq->data;
        mrq->data->error = 0;
        mrq->data->mrq = mrq;
        if (mrq->stop) {
            mrq->data->stop = mrq->stop;
            mrq->stop->error = 0;
            mrq->stop->mrq = mrq;
        }
    }
    mmc_host_clk_hold(host);
    led_trigger_event(host->led, LED_FULL);
    host->ops->request(host, mrq);
}

void mmc_start_bkops(struct mmc_card *card, bool from_exception)
{
    int err;
    int timeout;
    bool use_busy_signal;

    BUG_ON(!card);

    if (!card->ext_csd.bkops_en || mmc_card_doing_bkops(card))
        return;

    err = mmc_read_bkops_status(card);
    if (err) {
        pr_err("%s: Failed to read bkops status: %d\n",
               mmc_hostname(card->host), err);
        return;
    }

    if (!card->ext_csd.raw_bkops_status)
        return;

    if (card->ext_csd.raw_bkops_status < EXT_CSD_BKOPS_LEVEL_2 &&
        from_exception)
        return;

    mmc_claim_host(card->host);
    if (card->ext_csd.raw_bkops_status >= EXT_CSD_BKOPS_LEVEL_2) {
        timeout = MMC_BKOPS_MAX_TIMEOUT;
        use_busy_signal = true;
    } else {
        timeout = 0;
        use_busy_signal = false;
    }

    err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
            EXT_CSD_BKOPS_START, 1, timeout, use_busy_signal);
    if (err) {
        pr_warn("%s: Error %d starting bkops\n",
            mmc_hostname(card->host), err);
        goto out;
    }

    /*
     * For urgent bkops status (LEVEL_2 and more)
     * bkops executed synchronously, otherwise
     * the operation is in progress
     */
    if (!use_busy_signal)
        mmc_card_set_doing_bkops(card);
out:
    mmc_release_host(card->host);
}
EXPORT_SYMBOL(mmc_start_bkops);

static void mmc_wait_done(struct mmc_request *mrq)
{
    complete(&mrq->completion);
}

static int __mmc_start_req(struct mmc_host *host, struct mmc_request *mrq)
{
    init_completion(&mrq->completion);
    mrq->done = mmc_wait_done;
    if (mmc_card_removed(host->card)) {
        mrq->cmd->error = -ENOMEDIUM;
        complete(&mrq->completion);
        return -ENOMEDIUM;
    }
    mmc_start_request(host, mrq);
    return 0;
}

static void mmc_wait_for_req_done(struct mmc_host *host,
                  struct mmc_request *mrq)
{
    struct mmc_command *cmd;

    while (1) {
        wait_for_completion(&mrq->completion);

        cmd = mrq->cmd;
        if (!cmd->error || !cmd->retries ||
            mmc_card_removed(host->card))
            break;

        pr_debug("%s: req failed (CMD%u): %d, retrying...\n",
             mmc_hostname(host), cmd->opcode, cmd->error);
        cmd->retries--;
        cmd->error = 0;
        host->ops->request(host, mrq);
    }
}

static void mmc_pre_req(struct mmc_host *host, struct mmc_request *mrq,
         bool is_first_req)
{
    if (host->ops->pre_req) {
        mmc_host_clk_hold(host);
        host->ops->pre_req(host, mrq, is_first_req);
        mmc_host_clk_release(host);
    }
}

static void mmc_post_req(struct mmc_host *host, struct mmc_request *mrq,
             int err)
{
    if (host->ops->post_req) {
        mmc_host_clk_hold(host);
        host->ops->post_req(host, mrq, err);
        mmc_host_clk_release(host);
    }
}

struct mmc_async_req *mmc_start_req(struct mmc_host *host,
                    struct mmc_async_req *areq, int *error)
{
    int err = 0;
    int start_err = 0;
    struct mmc_async_req *data = host->areq;

    /* Prepare a new request */
    if (areq)
        mmc_pre_req(host, areq->mrq, !host->areq);

    if (host->areq) {
        mmc_wait_for_req_done(host, host->areq->mrq);
        err = host->areq->err_check(host->card, host->areq);
        /*
         * Check BKOPS urgency for each R1 response
         */
        if (host->card && mmc_card_mmc(host->card) &&
            ((mmc_resp_type(host->areq->mrq->cmd) == MMC_RSP_R1) ||
             (mmc_resp_type(host->areq->mrq->cmd) == MMC_RSP_R1B)) &&
            (host->areq->mrq->cmd->resp[0] & R1_EXCEPTION_EVENT))
            mmc_start_bkops(host->card, true);
    }

    if (!err && areq)
        start_err = __mmc_start_req(host, areq->mrq);

    if (host->areq)
        mmc_post_req(host, host->areq->mrq, 0);

     /* Cancel a prepared request if it was not started. */
    if ((err || start_err) && areq)
            mmc_post_req(host, areq->mrq, -EINVAL);

    if (err)
        host->areq = NULL;
    else
        host->areq = areq;

    if (error)
        *error = err;
    return data;
}
EXPORT_SYMBOL(mmc_start_req);

void mmc_wait_for_req(struct mmc_host *host, struct mmc_request *mrq)
{
    __mmc_start_req(host, mrq);
    mmc_wait_for_req_done(host, mrq);
}
EXPORT_SYMBOL(mmc_wait_for_req);

int mmc_interrupt_hpi(struct mmc_card *card)
{
    int err;
    u32 status;
    unsigned long prg_wait;

    BUG_ON(!card);

    if (!card->ext_csd.hpi_en) {
        pr_info("%s: HPI enable bit unset\n", mmc_hostname(card->host));
        return 1;
    }

    mmc_claim_host(card->host);
    err = mmc_send_status(card, &status);
    if (err) {
        pr_err("%s: Get card status fail\n", mmc_hostname(card->host));
        goto out;
    }

    switch (R1_CURRENT_STATE(status)) {
    case R1_STATE_IDLE:
    case R1_STATE_READY:
    case R1_STATE_STBY:
    case R1_STATE_TRAN:
        /*
         * In idle and transfer states, HPI is not needed and the caller
         * can issue the next intended command immediately
         */
        goto out;
    case R1_STATE_PRG:
        break;
    default:
        /* In all other states, it's illegal to issue HPI */
        pr_debug("%s: HPI cannot be sent. Card state=%d\n",
            mmc_hostname(card->host), R1_CURRENT_STATE(status));
        err = -EINVAL;
        goto out;
    }

    err = mmc_send_hpi_cmd(card, &status);
    if (err)
        goto out;

    prg_wait = jiffies + msecs_to_jiffies(card->ext_csd.out_of_int_time);
    do {
        err = mmc_send_status(card, &status);

        if (!err && R1_CURRENT_STATE(status) == R1_STATE_TRAN)
            break;
        if (time_after(jiffies, prg_wait))
            err = -ETIMEDOUT;
    } while (!err);

out:
    mmc_release_host(card->host);
    return err;
}
EXPORT_SYMBOL(mmc_interrupt_hpi);

int mmc_wait_for_cmd(struct mmc_host *host, struct mmc_command *cmd, int retries)
{
    struct mmc_request mrq = {NULL};

    WARN_ON(!host->claimed);

    memset(cmd->resp, 0, sizeof(cmd->resp));
    cmd->retries = retries;

    mrq.cmd = cmd;
    cmd->data = NULL;

    mmc_wait_for_req(host, &mrq);

    return cmd->error;
}

EXPORT_SYMBOL(mmc_wait_for_cmd);

int mmc_stop_bkops(struct mmc_card *card)
{
    int err = 0;

    BUG_ON(!card);
    err = mmc_interrupt_hpi(card);

    /*
     * If err is EINVAL, we can't issue an HPI.
     * It should complete the BKOPS.
     */
    if (!err || (err == -EINVAL)) {
        mmc_card_clr_doing_bkops(card);
        err = 0;
    }

    return err;
}
EXPORT_SYMBOL(mmc_stop_bkops);

int mmc_read_bkops_status(struct mmc_card *card)
{
    int err;
    u8 *ext_csd;

    /*
     * In future work, we should consider storing the entire ext_csd.
     */
    ext_csd = kmalloc(512, GFP_KERNEL);
    if (!ext_csd) {
        pr_err("%s: could not allocate buffer to receive the ext_csd.\n",
               mmc_hostname(card->host));
        return -ENOMEM;
    }

    mmc_claim_host(card->host);
    err = mmc_send_ext_csd(card, ext_csd);
    mmc_release_host(card->host);
    if (err)
        goto out;

    card->ext_csd.raw_bkops_status = ext_csd[EXT_CSD_BKOPS_STATUS];
    card->ext_csd.raw_exception_status = ext_csd[EXT_CSD_EXP_EVENTS_STATUS];
out:
    kfree(ext_csd);
    return err;
}
EXPORT_SYMBOL(mmc_read_bkops_status);

void mmc_set_data_timeout(struct mmc_data *data, const struct mmc_card *card)
{
    unsigned int mult;

    /*
     * SDIO cards only define an upper 1 s limit on access.
     */
    if (mmc_card_sdio(card)) {
        data->timeout_ns = 1000000000;
        data->timeout_clks = 0;
        return;
    }

    /*
     * SD cards use a 100 multiplier rather than 10
     */
    mult = mmc_card_sd(card) ? 100 : 10;

    /*
     * Scale up the multiplier (and therefore the timeout) by
     * the r2w factor for writes.
     */
    if (data->flags & MMC_DATA_WRITE)
        mult <<= card->csd.r2w_factor;

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

    /*
     * SD cards also have an upper limit on the timeout.
     */
    if (mmc_card_sd(card)) {
        unsigned int timeout_us, limit_us;

        timeout_us = data->timeout_ns / 1000;
        if (mmc_host_clk_rate(card->host))
            timeout_us += data->timeout_clks * 1000 /
                (mmc_host_clk_rate(card->host) / 1000);

        if (data->flags & MMC_DATA_WRITE)
            /*
             * The MMC spec "It is strongly recommended
             * for hosts to implement more than 500ms
             * timeout value even if the card indicates
             * the 250ms maximum busy length."  Even the
             * previous value of 300ms is known to be
             * insufficient for some cards.
             */
            limit_us = 3000000;
        else
            limit_us = 100000;

        /*
         * SDHC cards always use these fixed values.
         */
        if (timeout_us > limit_us || mmc_card_blockaddr(card)) {
            data->timeout_ns = limit_us * 1000;
            data->timeout_clks = 0;
        }
    }

    /*
     * Some cards require longer data read timeout than indicated in CSD.
     * Address this by setting the read timeout to a "reasonably high"
     * value. For the cards tested, 300ms has proven enough. If necessary,
     * this value can be increased if other problematic cards require this.
     */
    if (mmc_card_long_read_time(card) && data->flags & MMC_DATA_READ) {
        data->timeout_ns = 300000000;
        data->timeout_clks = 0;
    }

    /*
     * Some cards need very high timeouts if driven in SPI mode.
     * The worst observed timeout was 900ms after writing a
     * continuous stream of data until the internal logic
     * overflowed.
     */
    if (mmc_host_is_spi(card->host)) {
        if (data->flags & MMC_DATA_WRITE) {
            if (data->timeout_ns < 1000000000)
                data->timeout_ns = 1000000000;  /* 1s */
        } else {
            if (data->timeout_ns < 100000000)
                data->timeout_ns =  100000000;  /* 100ms */
        }
    }
}
EXPORT_SYMBOL(mmc_set_data_timeout);

unsigned int mmc_align_data_size(struct mmc_card *card, unsigned int sz)
{
    /*
     * FIXME: We don't have a system for the controller to tell
     * the core about its problems yet, so for now we just 32-bit
     * align the size.
     */
    sz = ((sz + 3) / 4) * 4;

    return sz;
}
EXPORT_SYMBOL(mmc_align_data_size);

int __mmc_claim_host(struct mmc_host *host, atomic_t *abort)
{
    DECLARE_WAITQUEUE(wait, current);
    unsigned long flags;
    int stop;

    might_sleep();

    add_wait_queue(&host->wq, &wait);
    spin_lock_irqsave(&host->lock, flags);
    while (1) {
        set_current_state(TASK_UNINTERRUPTIBLE);
        stop = abort ? atomic_read(abort) : 0;
        if (stop || !host->claimed || host->claimer == current)
            break;
        spin_unlock_irqrestore(&host->lock, flags);
        schedule();
        spin_lock_irqsave(&host->lock, flags);
    }
    set_current_state(TASK_RUNNING);
    if (!stop) {
        host->claimed = 1;
        host->claimer = current;
        host->claim_cnt += 1;
    } else
        wake_up(&host->wq);
    spin_unlock_irqrestore(&host->lock, flags);
    remove_wait_queue(&host->wq, &wait);
    if (host->ops->enable && !stop && host->claim_cnt == 1)
        host->ops->enable(host);
    return stop;
}

EXPORT_SYMBOL(__mmc_claim_host);

int mmc_try_claim_host(struct mmc_host *host)
{
    int claimed_host = 0;
    unsigned long flags;

    spin_lock_irqsave(&host->lock, flags);
    if (!host->claimed || host->claimer == current) {
        host->claimed = 1;
        host->claimer = current;
        host->claim_cnt += 1;
        claimed_host = 1;
    }
    spin_unlock_irqrestore(&host->lock, flags);
    if (host->ops->enable && claimed_host && host->claim_cnt == 1)
        host->ops->enable(host);
    return claimed_host;
}
EXPORT_SYMBOL(mmc_try_claim_host);

void mmc_release_host(struct mmc_host *host)
{
    unsigned long flags;

    WARN_ON(!host->claimed);

    if (host->ops->disable && host->claim_cnt == 1)
        host->ops->disable(host);

    spin_lock_irqsave(&host->lock, flags);
    if (--host->claim_cnt) {
        /* Release for nested claim */
        spin_unlock_irqrestore(&host->lock, flags);
    } else {
        host->claimed = 0;
        host->claimer = NULL;
        spin_unlock_irqrestore(&host->lock, flags);
        wake_up(&host->wq);
    }
}
EXPORT_SYMBOL(mmc_release_host);

/*
 * Internal function that does the actual ios call to the host driver,
 * optionally printing some debug output.
 */
static inline void mmc_set_ios(struct mmc_host *host)
{
    struct mmc_ios *ios = &host->ios;

    pr_debug("%s: clock %uHz busmode %u powermode %u cs %u Vdd %u "
        "width %u timing %u\n",
         mmc_hostname(host), ios->clock, ios->bus_mode,
         ios->power_mode, ios->chip_select, ios->vdd,
         ios->bus_width, ios->timing);

    if (ios->clock > 0)
        mmc_set_ungated(host);
    host->ops->set_ios(host, ios);
}

/*
 * Control chip select pin on a host.
 */
void mmc_set_chip_select(struct mmc_host *host, int mode)
{
    mmc_host_clk_hold(host);
    host->ios.chip_select = mode;
    mmc_set_ios(host);
    mmc_host_clk_release(host);
}

/*
 * Sets the host clock to the highest possible frequency that
 * is below "hz".
 */
static void __mmc_set_clock(struct mmc_host *host, unsigned int hz)
{
    WARN_ON(hz < host->f_min);

    if (hz > host->f_max)
        hz = host->f_max;

    host->ios.clock = hz;
    mmc_set_ios(host);
}

void mmc_set_clock(struct mmc_host *host, unsigned int hz)
{
    mmc_host_clk_hold(host);
    __mmc_set_clock(host, hz);
    mmc_host_clk_release(host);
}

#ifdef CONFIG_MMC_CLKGATE
/*
 * This gates the clock by setting it to 0 Hz.
 */
void mmc_gate_clock(struct mmc_host *host)
{
    unsigned long flags;

    spin_lock_irqsave(&host->clk_lock, flags);
    host->clk_old = host->ios.clock;
    host->ios.clock = 0;
    host->clk_gated = true;
    spin_unlock_irqrestore(&host->clk_lock, flags);
    mmc_set_ios(host);
}

/*
 * This restores the clock from gating by using the cached
 * clock value.
 */
void mmc_ungate_clock(struct mmc_host *host)
{
    /*
     * We should previously have gated the clock, so the clock shall
     * be 0 here! The clock may however be 0 during initialization,
     * when some request operations are performed before setting
     * the frequency. When ungate is requested in that situation
     * we just ignore the call.
     */
    if (host->clk_old) {
        BUG_ON(host->ios.clock);
        /* This call will also set host->clk_gated to false */
        __mmc_set_clock(host, host->clk_old);
    }
}

void mmc_set_ungated(struct mmc_host *host)
{
    unsigned long flags;

    /*
     * We've been given a new frequency while the clock is gated,
     * so make sure we regard this as ungating it.
     */
    spin_lock_irqsave(&host->clk_lock, flags);
    host->clk_gated = false;
    spin_unlock_irqrestore(&host->clk_lock, flags);
}

#else
void mmc_set_ungated(struct mmc_host *host)
{
}
#endif

/*
 * Change the bus mode (open drain/push-pull) of a host.
 */
void mmc_set_bus_mode(struct mmc_host *host, unsigned int mode)
{
    mmc_host_clk_hold(host);
    host->ios.bus_mode = mode;
    mmc_set_ios(host);
    mmc_host_clk_release(host);
}

/*
 * Change data bus width of a host.
 */
void mmc_set_bus_width(struct mmc_host *host, unsigned int width)
{
    mmc_host_clk_hold(host);
    host->ios.bus_width = width;
    mmc_set_ios(host);
    mmc_host_clk_release(host);
}

static int mmc_vdd_to_ocrbitnum(int vdd, bool low_bits)
{
    const int max_bit = ilog2(MMC_VDD_35_36);
    int bit;

    if (vdd < 1650 || vdd > 3600)
        return -EINVAL;

    if (vdd >= 1650 && vdd <= 1950)
        return ilog2(MMC_VDD_165_195);

    if (low_bits)
        vdd -= 1;

    /* Base 2000 mV, step 100 mV, bit's base 8. */
    bit = (vdd - 2000) / 100 + 8;
    if (bit > max_bit)
        return max_bit;
    return bit;
}

u32 mmc_vddrange_to_ocrmask(int vdd_min, int vdd_max)
{
    u32 mask = 0;

    if (vdd_max < vdd_min)
        return 0;

    /* Prefer high bits for the boundary vdd_max values. */
    vdd_max = mmc_vdd_to_ocrbitnum(vdd_max, false);
    if (vdd_max < 0)
        return 0;

    /* Prefer low bits for the boundary vdd_min values. */
    vdd_min = mmc_vdd_to_ocrbitnum(vdd_min, true);
    if (vdd_min < 0)
        return 0;

    /* Fill the mask, from max bit to min bit. */
    while (vdd_max >= vdd_min)
        mask |= 1 << vdd_max--;

    return mask;
}
EXPORT_SYMBOL(mmc_vddrange_to_ocrmask);

#ifdef CONFIG_REGULATOR

int mmc_regulator_get_ocrmask(struct regulator *supply)
{
    int         result = 0;
    int         count;
    int         i;

    count = regulator_count_voltages(supply);
    if (count < 0)
        return count;

    for (i = 0; i < count; i++) {
        int     vdd_uV;
        int     vdd_mV;

        vdd_uV = regulator_list_voltage(supply, i);
        if (vdd_uV <= 0)
            continue;

        vdd_mV = vdd_uV / 1000;
        result |= mmc_vddrange_to_ocrmask(vdd_mV, vdd_mV);
    }

    return result;
}
EXPORT_SYMBOL_GPL(mmc_regulator_get_ocrmask);

int mmc_regulator_set_ocr(struct mmc_host *mmc,
            struct regulator *supply,
            unsigned short vdd_bit)
{
    int         result = 0;
    int         min_uV, max_uV;

    if (vdd_bit) {
        int     tmp;
        int     voltage;

        /*
         * REVISIT mmc_vddrange_to_ocrmask() may have set some
         * bits this regulator doesn't quite support ... don't
         * be too picky, most cards and regulators are OK with
         * a 0.1V range goof (it's a small error percentage).
         */
        tmp = vdd_bit - ilog2(MMC_VDD_165_195);
        if (tmp == 0) {
            min_uV = 1650 * 1000;
            max_uV = 1950 * 1000;
        } else {
            min_uV = 1900 * 1000 + tmp * 100 * 1000;
            max_uV = min_uV + 100 * 1000;
        }

        /*
         * If we're using a fixed/static regulator, don't call
         * regulator_set_voltage; it would fail.
         */
        voltage = regulator_get_voltage(supply);

        if (regulator_count_voltages(supply) == 1)
            min_uV = max_uV = voltage;

        if (voltage < 0)
            result = voltage;
        else if (voltage < min_uV || voltage > max_uV)
            result = regulator_set_voltage(supply, min_uV, max_uV);
        else
            result = 0;

        if (result == 0 && !mmc->regulator_enabled) {
            result = regulator_enable(supply);
            if (!result)
                mmc->regulator_enabled = true;
        }
    } else if (mmc->regulator_enabled) {
        result = regulator_disable(supply);
        if (result == 0)
            mmc->regulator_enabled = false;
    }

    if (result)
        dev_err(mmc_dev(mmc),
            "could not set regulator OCR (%d)\n", result);
    return result;
}
EXPORT_SYMBOL_GPL(mmc_regulator_set_ocr);

int mmc_regulator_get_supply(struct mmc_host *mmc)
{
    struct device *dev = mmc_dev(mmc);
    struct regulator *supply;
    int ret;

    supply = devm_regulator_get(dev, "vmmc");
    mmc->supply.vmmc = supply;
    mmc->supply.vqmmc = devm_regulator_get(dev, "vqmmc");

    if (IS_ERR(supply))
        return PTR_ERR(supply);

    ret = mmc_regulator_get_ocrmask(supply);
    if (ret > 0)
        mmc->ocr_avail = ret;
    else
        dev_warn(mmc_dev(mmc), "Failed getting OCR mask: %d\n", ret);

    return 0;
}
EXPORT_SYMBOL_GPL(mmc_regulator_get_supply);

#endif /* CONFIG_REGULATOR */

/*
 * Mask off any voltages we don't support and select
 * the lowest voltage
 */
u32 mmc_select_voltage(struct mmc_host *host, u32 ocr)
{
    int bit;

    ocr &= host->ocr_avail;

    bit = ffs(ocr);
    if (bit) {
        bit -= 1;

        ocr &= 3 << bit;

        mmc_host_clk_hold(host);
        host->ios.vdd = bit;
        mmc_set_ios(host);
        mmc_host_clk_release(host);
    } else {
        pr_warning("%s: host doesn't support card's voltages\n",
                mmc_hostname(host));
        ocr = 0;
    }

    return ocr;
}

int mmc_set_signal_voltage(struct mmc_host *host, int signal_voltage, bool cmd11)
{
    struct mmc_command cmd = {0};
    int err = 0;

    BUG_ON(!host);

    /*
     * Send CMD11 only if the request is to switch the card to
     * 1.8V signalling.
     */
    if ((signal_voltage != MMC_SIGNAL_VOLTAGE_330) && cmd11) {
        cmd.opcode = SD_SWITCH_VOLTAGE;
        cmd.arg = 0;
        cmd.flags = MMC_RSP_R1 | MMC_CMD_AC;

        err = mmc_wait_for_cmd(host, &cmd, 0);
        if (err)
            return err;

        if (!mmc_host_is_spi(host) && (cmd.resp[0] & R1_ERROR))
            return -EIO;
    }

    host->ios.signal_voltage = signal_voltage;

    if (host->ops->start_signal_voltage_switch) {
        mmc_host_clk_hold(host);
        err = host->ops->start_signal_voltage_switch(host, &host->ios);
        mmc_host_clk_release(host);
    }

    return err;
}

/*
 * Select timing parameters for host.
 */
void mmc_set_timing(struct mmc_host *host, unsigned int timing)
{
    mmc_host_clk_hold(host);
    host->ios.timing = timing;
    mmc_set_ios(host);
    mmc_host_clk_release(host);
}

/*
 * Select appropriate driver type for host.
 */
void mmc_set_driver_type(struct mmc_host *host, unsigned int drv_type)
{
    mmc_host_clk_hold(host);
    host->ios.drv_type = drv_type;
    mmc_set_ios(host);
    mmc_host_clk_release(host);
}

/*
 * Apply power to the MMC stack.  This is a two-stage process.
 * First, we enable power to the card without the clock running.
 * We then wait a bit for the power to stabilise.  Finally,
 * enable the bus drivers and clock to the card.
 *
 * We must _NOT_ enable the clock prior to power stablising.
 *
 * If a host does all the power sequencing itself, ignore the
 * initial MMC_POWER_UP stage.
 */
static void mmc_power_up(struct mmc_host *host)
{
    int bit;

    if (host->ios.power_mode == MMC_POWER_ON)
        return;

    mmc_host_clk_hold(host);

    /* If ocr is set, we use it */
    if (host->ocr)
        bit = ffs(host->ocr) - 1;
    else
        bit = fls(host->ocr_avail) - 1;

    host->ios.vdd = bit;
    if (mmc_host_is_spi(host))
        host->ios.chip_select = MMC_CS_HIGH;
    else
        host->ios.chip_select = MMC_CS_DONTCARE;
    host->ios.bus_mode = MMC_BUSMODE_PUSHPULL;
    host->ios.power_mode = MMC_POWER_UP;
    host->ios.bus_width = MMC_BUS_WIDTH_1;
    host->ios.timing = MMC_TIMING_LEGACY;
    mmc_set_ios(host);

    /* Set signal voltage to 3.3V */
    mmc_set_signal_voltage(host, MMC_SIGNAL_VOLTAGE_330, false);

    /*
     * This delay should be sufficient to allow the power supply
     * to reach the minimum voltage.
     */
    mmc_delay(10);

    host->ios.clock = host->f_init;

    host->ios.power_mode = MMC_POWER_ON;
    mmc_set_ios(host);

    /*
     * This delay must be at least 74 clock sizes, or 1 ms, or the
     * time required to reach a stable voltage.
     */
    mmc_delay(10);

    mmc_host_clk_release(host);
}

void mmc_power_off(struct mmc_host *host)
{
    if (host->ios.power_mode == MMC_POWER_OFF)
        return;

    mmc_host_clk_hold(host);

    host->ios.clock = 0;
    host->ios.vdd = 0;


    /*
     * Reset ocr mask to be the highest possible voltage supported for
     * this mmc host. This value will be used at next power up.
     */
    host->ocr = 1 << (fls(host->ocr_avail) - 1);

    if (!mmc_host_is_spi(host)) {
        host->ios.bus_mode = MMC_BUSMODE_OPENDRAIN;
        host->ios.chip_select = MMC_CS_DONTCARE;
    }
    host->ios.power_mode = MMC_POWER_OFF;
    host->ios.bus_width = MMC_BUS_WIDTH_1;
    host->ios.timing = MMC_TIMING_LEGACY;
    mmc_set_ios(host);

    /*
     * Some configurations, such as the 802.11 SDIO card in the OLPC
     * XO-1.5, require a short delay after poweroff before the card
     * can be successfully turned on again.
     */
    mmc_delay(1);

    mmc_host_clk_release(host);
}

/*
 * Cleanup when the last reference to the bus operator is dropped.
 */
static void __mmc_release_bus(struct mmc_host *host)
{
    BUG_ON(!host);
    BUG_ON(host->bus_refs);
    BUG_ON(!host->bus_dead);

    host->bus_ops = NULL;
}

/*
 * Increase reference count of bus operator
 */
static inline void mmc_bus_get(struct mmc_host *host)
{
    unsigned long flags;

    spin_lock_irqsave(&host->lock, flags);
    host->bus_refs++;
    spin_unlock_irqrestore(&host->lock, flags);
}

/*
 * Decrease reference count of bus operator and free it if
 * it is the last reference.
 */
static inline void mmc_bus_put(struct mmc_host *host)
{
    unsigned long flags;

    spin_lock_irqsave(&host->lock, flags);
    host->bus_refs--;
    if ((host->bus_refs == 0) && host->bus_ops)
        __mmc_release_bus(host);
    spin_unlock_irqrestore(&host->lock, flags);
}

/*
 * Assign a mmc bus handler to a host. Only one bus handler may control a
 * host at any given time.
 */
void mmc_attach_bus(struct mmc_host *host, const struct mmc_bus_ops *ops)
{
    unsigned long flags;

    BUG_ON(!host);
    BUG_ON(!ops);

    WARN_ON(!host->claimed);

    spin_lock_irqsave(&host->lock, flags);

    BUG_ON(host->bus_ops);
    BUG_ON(host->bus_refs);

    host->bus_ops = ops;
    host->bus_refs = 1;
    host->bus_dead = 0;

    spin_unlock_irqrestore(&host->lock, flags);
}

/*
 * Remove the current bus handler from a host.
 */
void mmc_detach_bus(struct mmc_host *host)
{
    unsigned long flags;

    BUG_ON(!host);

    WARN_ON(!host->claimed);
    WARN_ON(!host->bus_ops);

    spin_lock_irqsave(&host->lock, flags);

    host->bus_dead = 1;

    spin_unlock_irqrestore(&host->lock, flags);

    mmc_bus_put(host);
}

void mmc_detect_change(struct mmc_host *host, unsigned long delay)
{
#ifdef CONFIG_MMC_DEBUG
    unsigned long flags;
    spin_lock_irqsave(&host->lock, flags);
    WARN_ON(host->removed);
    spin_unlock_irqrestore(&host->lock, flags);
#endif
    host->detect_change = 1;
    mmc_schedule_delayed_work(&host->detect, delay);
}

EXPORT_SYMBOL(mmc_detect_change);

void mmc_init_erase(struct mmc_card *card)
{
    unsigned int sz;

    if (is_power_of_2(card->erase_size))
        card->erase_shift = ffs(card->erase_size) - 1;
    else
        card->erase_shift = 0;

    /*
     * It is possible to erase an arbitrarily large area of an SD or MMC
     * card.  That is not desirable because it can take a long time
     * (minutes) potentially delaying more important I/O, and also the
     * timeout calculations become increasingly hugely over-estimated.
     * Consequently, 'pref_erase' is defined as a guide to limit erases
     * to that size and alignment.
     *
     * For SD cards that define Allocation Unit size, limit erases to one
     * Allocation Unit at a time.  For MMC cards that define High Capacity
     * Erase Size, whether it is switched on or not, limit to that size.
     * Otherwise just have a stab at a good value.  For modern cards it
     * will end up being 4MiB.  Note that if the value is too small, it
     * can end up taking longer to erase.
     */
    if (mmc_card_sd(card) && card->ssr.au) {
        card->pref_erase = card->ssr.au;
        card->erase_shift = ffs(card->ssr.au) - 1;
    } else if (card->ext_csd.hc_erase_size) {
        card->pref_erase = card->ext_csd.hc_erase_size;
    } else {
        sz = (card->csd.capacity << (card->csd.read_blkbits - 9)) >> 11;
        if (sz < 128)
            card->pref_erase = 512 * 1024 / 512;
        else if (sz < 512)
            card->pref_erase = 1024 * 1024 / 512;
        else if (sz < 1024)
            card->pref_erase = 2 * 1024 * 1024 / 512;
        else
            card->pref_erase = 4 * 1024 * 1024 / 512;
        if (card->pref_erase < card->erase_size)
            card->pref_erase = card->erase_size;
        else {
            sz = card->pref_erase % card->erase_size;
            if (sz)
                card->pref_erase += card->erase_size - sz;
        }
    }
}

static unsigned int mmc_mmc_erase_timeout(struct mmc_card *card,
                          unsigned int arg, unsigned int qty)
{
    unsigned int erase_timeout;

    if (arg == MMC_DISCARD_ARG ||
        (arg == MMC_TRIM_ARG && card->ext_csd.rev >= 6)) {
        erase_timeout = card->ext_csd.trim_timeout;
    } else if (card->ext_csd.erase_group_def & 1) {
        /* High Capacity Erase Group Size uses HC timeouts */
        if (arg == MMC_TRIM_ARG)
            erase_timeout = card->ext_csd.trim_timeout;
        else
            erase_timeout = card->ext_csd.hc_erase_timeout;
    } else {
        /* CSD Erase Group Size uses write timeout */
        unsigned int mult = (10 << card->csd.r2w_factor);
        unsigned int timeout_clks = card->csd.tacc_clks * mult;
        unsigned int timeout_us;

        /* Avoid overflow: e.g. tacc_ns=80000000 mult=1280 */
        if (card->csd.tacc_ns < 1000000)
            timeout_us = (card->csd.tacc_ns * mult) / 1000;
        else
            timeout_us = (card->csd.tacc_ns / 1000) * mult;

        /*
         * ios.clock is only a target.  The real clock rate might be
         * less but not that much less, so fudge it by multiplying by 2.
         */
        timeout_clks <<= 1;
        timeout_us += (timeout_clks * 1000) /
                  (mmc_host_clk_rate(card->host) / 1000);

        erase_timeout = timeout_us / 1000;

        /*
         * Theoretically, the calculation could underflow so round up
         * to 1ms in that case.
         */
        if (!erase_timeout)
            erase_timeout = 1;
    }

    /* Multiplier for secure operations */
    if (arg & MMC_SECURE_ARGS) {
        if (arg == MMC_SECURE_ERASE_ARG)
            erase_timeout *= card->ext_csd.sec_erase_mult;
        else
            erase_timeout *= card->ext_csd.sec_trim_mult;
    }

    erase_timeout *= qty;

    /*
     * Ensure at least a 1 second timeout for SPI as per
     * 'mmc_set_data_timeout()'
     */
    if (mmc_host_is_spi(card->host) && erase_timeout < 1000)
        erase_timeout = 1000;

    return erase_timeout;
}

static unsigned int mmc_sd_erase_timeout(struct mmc_card *card,
                     unsigned int arg,
                     unsigned int qty)
{
    unsigned int erase_timeout;

    if (card->ssr.erase_timeout) {
        /* Erase timeout specified in SD Status Register (SSR) */
        erase_timeout = card->ssr.erase_timeout * qty +
                card->ssr.erase_offset;
    } else {
        /*
         * Erase timeout not specified in SD Status Register (SSR) so
         * use 250ms per write block.
         */
        erase_timeout = 250 * qty;
    }

    /* Must not be less than 1 second */
    if (erase_timeout < 1000)
        erase_timeout = 1000;

    return erase_timeout;
}

static unsigned int mmc_erase_timeout(struct mmc_card *card,
                      unsigned int arg,
                      unsigned int qty)
{
    if (mmc_card_sd(card))
        return mmc_sd_erase_timeout(card, arg, qty);
    else
        return mmc_mmc_erase_timeout(card, arg, qty);
}

static int mmc_do_erase(struct mmc_card *card, unsigned int from,
            unsigned int to, unsigned int arg)
{
    struct mmc_command cmd = {0};
    unsigned int qty = 0;
    int err;

    /*
     * qty is used to calculate the erase timeout which depends on how many
     * erase groups (or allocation units in SD terminology) are affected.
     * We count erasing part of an erase group as one erase group.
     * For SD, the allocation units are always a power of 2.  For MMC, the
     * erase group size is almost certainly also power of 2, but it does not
     * seem to insist on that in the JEDEC standard, so we fall back to
     * division in that case.  SD may not specify an allocation unit size,
     * in which case the timeout is based on the number of write blocks.
     *
     * Note that the timeout for secure trim 2 will only be correct if the
     * number of erase groups specified is the same as the total of all
     * preceding secure trim 1 commands.  Since the power may have been
     * lost since the secure trim 1 commands occurred, it is generally
     * impossible to calculate the secure trim 2 timeout correctly.
     */
    if (card->erase_shift)
        qty += ((to >> card->erase_shift) -
            (from >> card->erase_shift)) + 1;
    else if (mmc_card_sd(card))
        qty += to - from + 1;
    else
        qty += ((to / card->erase_size) -
            (from / card->erase_size)) + 1;

    if (!mmc_card_blockaddr(card)) {
        from <<= 9;
        to <<= 9;
    }

    if (mmc_card_sd(card))
        cmd.opcode = SD_ERASE_WR_BLK_START;
    else
        cmd.opcode = MMC_ERASE_GROUP_START;
    cmd.arg = from;
    cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_AC;
    err = mmc_wait_for_cmd(card->host, &cmd, 0);
    if (err) {
        pr_err("mmc_erase: group start error %d, "
               "status %#x\n", err, cmd.resp[0]);
        err = -EIO;
        goto out;
    }

    memset(&cmd, 0, sizeof(struct mmc_command));
    if (mmc_card_sd(card))
        cmd.opcode = SD_ERASE_WR_BLK_END;
    else
        cmd.opcode = MMC_ERASE_GROUP_END;
    cmd.arg = to;
    cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_AC;
    err = mmc_wait_for_cmd(card->host, &cmd, 0);
    if (err) {
        pr_err("mmc_erase: group end error %d, status %#x\n",
               err, cmd.resp[0]);
        err = -EIO;
        goto out;
    }

    memset(&cmd, 0, sizeof(struct mmc_command));
    cmd.opcode = MMC_ERASE;
    cmd.arg = arg;
    cmd.flags = MMC_RSP_SPI_R1B | MMC_RSP_R1B | MMC_CMD_AC;
    cmd.cmd_timeout_ms = mmc_erase_timeout(card, arg, qty);
    err = mmc_wait_for_cmd(card->host, &cmd, 0);
    if (err) {
        pr_err("mmc_erase: erase error %d, status %#x\n",
               err, cmd.resp[0]);
        err = -EIO;
        goto out;
    }

    if (mmc_host_is_spi(card->host))
        goto out;

    do {
        memset(&cmd, 0, sizeof(struct mmc_command));
        cmd.opcode = MMC_SEND_STATUS;
        cmd.arg = card->rca << 16;
        cmd.flags = MMC_RSP_R1 | MMC_CMD_AC;
        /* Do not retry else we can't see errors */
        err = mmc_wait_for_cmd(card->host, &cmd, 0);
        if (err || (cmd.resp[0] & 0xFDF92000)) {
            pr_err("error %d requesting status %#x\n",
                err, cmd.resp[0]);
            err = -EIO;
            goto out;
        }
    } while (!(cmd.resp[0] & R1_READY_FOR_DATA) ||
         R1_CURRENT_STATE(cmd.resp[0]) == R1_STATE_PRG);
out:
    return err;
}

int mmc_erase(struct mmc_card *card, unsigned int from, unsigned int nr,
          unsigned int arg)
{
    unsigned int rem, to = from + nr;

    if (!(card->host->caps & MMC_CAP_ERASE) ||
        !(card->csd.cmdclass & CCC_ERASE))
        return -EOPNOTSUPP;

    if (!card->erase_size)
        return -EOPNOTSUPP;

    if (mmc_card_sd(card) && arg != MMC_ERASE_ARG)
        return -EOPNOTSUPP;

    if ((arg & MMC_SECURE_ARGS) &&
        !(card->ext_csd.sec_feature_support & EXT_CSD_SEC_ER_EN))
        return -EOPNOTSUPP;

    if ((arg & MMC_TRIM_ARGS) &&
        !(card->ext_csd.sec_feature_support & EXT_CSD_SEC_GB_CL_EN))
        return -EOPNOTSUPP;

    if (arg == MMC_SECURE_ERASE_ARG) {
        if (from % card->erase_size || nr % card->erase_size)
            return -EINVAL;
    }

    if (arg == MMC_ERASE_ARG) {
        rem = from % card->erase_size;
        if (rem) {
            rem = card->erase_size - rem;
            from += rem;
            if (nr > rem)
                nr -= rem;
            else
                return 0;
        }
        rem = nr % card->erase_size;
        if (rem)
            nr -= rem;
    }

    if (nr == 0)
        return 0;

    to = from + nr;

    if (to <= from)
        return -EINVAL;

    /* 'from' and 'to' are inclusive */
    to -= 1;

    return mmc_do_erase(card, from, to, arg);
}
EXPORT_SYMBOL(mmc_erase);

int mmc_can_erase(struct mmc_card *card)
{
    if ((card->host->caps & MMC_CAP_ERASE) &&
        (card->csd.cmdclass & CCC_ERASE) && card->erase_size)
        return 1;
    return 0;
}
EXPORT_SYMBOL(mmc_can_erase);

int mmc_can_trim(struct mmc_card *card)
{
    if (card->ext_csd.sec_feature_support & EXT_CSD_SEC_GB_CL_EN)
        return 1;
    return 0;
}
EXPORT_SYMBOL(mmc_can_trim);

int mmc_can_discard(struct mmc_card *card)
{
    /*
     * As there's no way to detect the discard support bit at v4.5
     * use the s/w feature support filed.
     */
    if (card->ext_csd.feature_support & MMC_DISCARD_FEATURE)
        return 1;
    return 0;
}
EXPORT_SYMBOL(mmc_can_discard);

int mmc_can_sanitize(struct mmc_card *card)
{
    if (!mmc_can_trim(card) && !mmc_can_erase(card))
        return 0;
    if (card->ext_csd.sec_feature_support & EXT_CSD_SEC_SANITIZE)
        return 1;
    return 0;
}
EXPORT_SYMBOL(mmc_can_sanitize);

int mmc_can_secure_erase_trim(struct mmc_card *card)
{
    if (card->ext_csd.sec_feature_support & EXT_CSD_SEC_ER_EN)
        return 1;
    return 0;
}
EXPORT_SYMBOL(mmc_can_secure_erase_trim);

int mmc_erase_group_aligned(struct mmc_card *card, unsigned int from,
                unsigned int nr)
{
    if (!card->erase_size)
        return 0;
    if (from % card->erase_size || nr % card->erase_size)
        return 0;
    return 1;
}
EXPORT_SYMBOL(mmc_erase_group_aligned);

static unsigned int mmc_do_calc_max_discard(struct mmc_card *card,
                        unsigned int arg)
{
    struct mmc_host *host = card->host;
    unsigned int max_discard, x, y, qty = 0, max_qty, timeout;
    unsigned int last_timeout = 0;

    if (card->erase_shift)
        max_qty = UINT_MAX >> card->erase_shift;
    else if (mmc_card_sd(card))
        max_qty = UINT_MAX;
    else
        max_qty = UINT_MAX / card->erase_size;

    /* Find the largest qty with an OK timeout */
    do {
        y = 0;
        for (x = 1; x && x <= max_qty && max_qty - x >= qty; x <<= 1) {
            timeout = mmc_erase_timeout(card, arg, qty + x);
            if (timeout > host->max_discard_to)
                break;
            if (timeout < last_timeout)
                break;
            last_timeout = timeout;
            y = x;
        }
        qty += y;
    } while (y);

    if (!qty)
        return 0;

    if (qty == 1)
        return 1;

    /* Convert qty to sectors */
    if (card->erase_shift)
        max_discard = --qty << card->erase_shift;
    else if (mmc_card_sd(card))
        max_discard = qty;
    else
        max_discard = --qty * card->erase_size;

    return max_discard;
}

unsigned int mmc_calc_max_discard(struct mmc_card *card)
{
    struct mmc_host *host = card->host;
    unsigned int max_discard, max_trim;

    if (!host->max_discard_to)
        return UINT_MAX;

    /*
     * Without erase_group_def set, MMC erase timeout depends on clock
     * frequence which can change.  In that case, the best choice is
     * just the preferred erase size.
     */
    if (mmc_card_mmc(card) && !(card->ext_csd.erase_group_def & 1))
        return card->pref_erase;

    max_discard = mmc_do_calc_max_discard(card, MMC_ERASE_ARG);
    if (mmc_can_trim(card)) {
        max_trim = mmc_do_calc_max_discard(card, MMC_TRIM_ARG);
        if (max_trim < max_discard)
            max_discard = max_trim;
    } else if (max_discard < card->erase_size) {
        max_discard = 0;
    }
    pr_debug("%s: calculated max. discard sectors %u for timeout %u ms\n",
         mmc_hostname(host), max_discard, host->max_discard_to);
    return max_discard;
}
EXPORT_SYMBOL(mmc_calc_max_discard);

int mmc_set_blocklen(struct mmc_card *card, unsigned int blocklen)
{
    struct mmc_command cmd = {0};

    if (mmc_card_blockaddr(card) || mmc_card_ddr_mode(card))
        return 0;

    cmd.opcode = MMC_SET_BLOCKLEN;
    cmd.arg = blocklen;
    cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_AC;
    return mmc_wait_for_cmd(card->host, &cmd, 5);
}
EXPORT_SYMBOL(mmc_set_blocklen);

static void mmc_hw_reset_for_init(struct mmc_host *host)
{
    if (!(host->caps & MMC_CAP_HW_RESET) || !host->ops->hw_reset)
        return;
    mmc_host_clk_hold(host);
    host->ops->hw_reset(host);
    mmc_host_clk_release(host);
}

int mmc_can_reset(struct mmc_card *card)
{
    u8 rst_n_function;

    if (!mmc_card_mmc(card))
        return 0;
    rst_n_function = card->ext_csd.rst_n_function;
    if ((rst_n_function & EXT_CSD_RST_N_EN_MASK) != EXT_CSD_RST_N_ENABLED)
        return 0;
    return 1;
}
EXPORT_SYMBOL(mmc_can_reset);

static int mmc_do_hw_reset(struct mmc_host *host, int check)
{
    struct mmc_card *card = host->card;

    if (!host->bus_ops->power_restore)
        return -EOPNOTSUPP;

    if (!(host->caps & MMC_CAP_HW_RESET) || !host->ops->hw_reset)
        return -EOPNOTSUPP;

    if (!card)
        return -EINVAL;

    if (!mmc_can_reset(card))
        return -EOPNOTSUPP;

    mmc_host_clk_hold(host);
    mmc_set_clock(host, host->f_init);

    host->ops->hw_reset(host);

    /* If the reset has happened, then a status command will fail */
    if (check) {
        struct mmc_command cmd = {0};
        int err;

        cmd.opcode = MMC_SEND_STATUS;
        if (!mmc_host_is_spi(card->host))
            cmd.arg = card->rca << 16;
        cmd.flags = MMC_RSP_SPI_R2 | MMC_RSP_R1 | MMC_CMD_AC;
        err = mmc_wait_for_cmd(card->host, &cmd, 0);
        if (!err) {
            mmc_host_clk_release(host);
            return -ENOSYS;
        }
    }

    host->card->state &= ~(MMC_STATE_HIGHSPEED | MMC_STATE_HIGHSPEED_DDR);
    if (mmc_host_is_spi(host)) {
        host->ios.chip_select = MMC_CS_HIGH;
        host->ios.bus_mode = MMC_BUSMODE_PUSHPULL;
    } else {
        host->ios.chip_select = MMC_CS_DONTCARE;
        host->ios.bus_mode = MMC_BUSMODE_OPENDRAIN;
    }
    host->ios.bus_width = MMC_BUS_WIDTH_1;
    host->ios.timing = MMC_TIMING_LEGACY;
    mmc_set_ios(host);

    mmc_host_clk_release(host);

    return host->bus_ops->power_restore(host);
}

int mmc_hw_reset(struct mmc_host *host)
{
    return mmc_do_hw_reset(host, 0);
}
EXPORT_SYMBOL(mmc_hw_reset);

int mmc_hw_reset_check(struct mmc_host *host)
{
    return mmc_do_hw_reset(host, 1);
}
EXPORT_SYMBOL(mmc_hw_reset_check);

static int mmc_rescan_try_freq(struct mmc_host *host, unsigned freq)
{
    host->f_init = freq;

#ifdef CONFIG_MMC_DEBUG
    pr_info("%s: %s: trying to init card at %u Hz\n",
        mmc_hostname(host), __func__, host->f_init);
#endif
    mmc_power_up(host);

    /*
     * Some eMMCs (with VCCQ always on) may not be reset after power up, so
     * do a hardware reset if possible.
     */
    mmc_hw_reset_for_init(host);

    /*
     * sdio_reset sends CMD52 to reset card.  Since we do not know
     * if the card is being re-initialized, just send it.  CMD52
     * should be ignored by SD/eMMC cards.
     */
    sdio_reset(host);
    mmc_go_idle(host);

    mmc_send_if_cond(host, host->ocr_avail);

    /* Order's important: probe SDIO, then SD, then MMC */
    if (!mmc_attach_sdio(host))
        return 0;
    if (!mmc_attach_sd(host))
        return 0;
    if (!mmc_attach_mmc(host))
        return 0;

    mmc_power_off(host);
    return -EIO;
}

int _mmc_detect_card_removed(struct mmc_host *host)
{
    int ret;

    if ((host->caps & MMC_CAP_NONREMOVABLE) || !host->bus_ops->alive)
        return 0;

    if (!host->card || mmc_card_removed(host->card))
        return 1;

    ret = host->bus_ops->alive(host);
    if (ret) {
        mmc_card_set_removed(host->card);
        pr_debug("%s: card remove detected\n", mmc_hostname(host));
    }

    return ret;
}

int mmc_detect_card_removed(struct mmc_host *host)
{
    struct mmc_card *card = host->card;
    int ret;

    WARN_ON(!host->claimed);

    if (!card)
        return 1;

    ret = mmc_card_removed(card);
    /*
     * The card will be considered unchanged unless we have been asked to
     * detect a change or host requires polling to provide card detection.
     */
    if (!host->detect_change && !(host->caps & MMC_CAP_NEEDS_POLL) &&
        !(host->caps2 & MMC_CAP2_DETECT_ON_ERR))
        return ret;

    host->detect_change = 0;
    if (!ret) {
        ret = _mmc_detect_card_removed(host);
        if (ret && (host->caps2 & MMC_CAP2_DETECT_ON_ERR)) {
            /*
             * Schedule a detect work as soon as possible to let a
             * rescan handle the card removal.
             */
            cancel_delayed_work(&host->detect);
            mmc_detect_change(host, 0);
        }
    }

    return ret;
}
EXPORT_SYMBOL(mmc_detect_card_removed);

void mmc_rescan(struct work_struct *work)
{
    struct mmc_host *host =
        container_of(work, struct mmc_host, detect.work);
    int i;

    if (host->rescan_disable)
        return;

    /* If there is a non-removable card registered, only scan once */
    if ((host->caps & MMC_CAP_NONREMOVABLE) && host->rescan_entered)
        return;
    host->rescan_entered = 1;

    mmc_bus_get(host);

    /*
     * if there is a _removable_ card registered, check whether it is
     * still present
     */
    if (host->bus_ops && host->bus_ops->detect && !host->bus_dead
        && !(host->caps & MMC_CAP_NONREMOVABLE))
        host->bus_ops->detect(host);

    host->detect_change = 0;

    /*
     * Let mmc_bus_put() free the bus/bus_ops if we've found that
     * the card is no longer present.
     */
    mmc_bus_put(host);
    mmc_bus_get(host);

    /* if there still is a card present, stop here */
    if (host->bus_ops != NULL) {
        mmc_bus_put(host);
        goto out;
    }

    /*
     * Only we can add a new handler, so it's safe to
     * release the lock here.
     */
    mmc_bus_put(host);

    if (host->ops->get_cd && host->ops->get_cd(host) == 0) {
        mmc_claim_host(host);
        mmc_power_off(host);
        mmc_release_host(host);
        goto out;
    }

    mmc_claim_host(host);
    for (i = 0; i < ARRAY_SIZE(freqs); i++) {
        if (!mmc_rescan_try_freq(host, max(freqs[i], host->f_min)))
            break;
        if (freqs[i] <= host->f_min)
            break;
    }
    mmc_release_host(host);

 out:
    if (host->caps & MMC_CAP_NEEDS_POLL)
        mmc_schedule_delayed_work(&host->detect, HZ);
}

void mmc_start_host(struct mmc_host *host)
{
    host->f_init = max(freqs[0], host->f_min);
    host->rescan_disable = 0;
    mmc_power_up(host);
    mmc_detect_change(host, 0);
}

void mmc_stop_host(struct mmc_host *host)
{
#ifdef CONFIG_MMC_DEBUG
    unsigned long flags;
    spin_lock_irqsave(&host->lock, flags);
    host->removed = 1;
    spin_unlock_irqrestore(&host->lock, flags);
#endif

    host->rescan_disable = 1;
    cancel_delayed_work_sync(&host->detect);
    mmc_flush_scheduled_work();

    /* clear pm flags now and let card drivers set them as needed */
    host->pm_flags = 0;

    mmc_bus_get(host);
    if (host->bus_ops && !host->bus_dead) {
        /* Calling bus_ops->remove() with a claimed host can deadlock */
        if (host->bus_ops->remove)
            host->bus_ops->remove(host);

        mmc_claim_host(host);
        mmc_detach_bus(host);
        mmc_power_off(host);
        mmc_release_host(host);
        mmc_bus_put(host);
        return;
    }
    mmc_bus_put(host);

    BUG_ON(host->card);

    mmc_power_off(host);
}

int mmc_power_save_host(struct mmc_host *host)
{
    int ret = 0;

#ifdef CONFIG_MMC_DEBUG
    pr_info("%s: %s: powering down\n", mmc_hostname(host), __func__);
#endif

    mmc_bus_get(host);

    if (!host->bus_ops || host->bus_dead || !host->bus_ops->power_restore) {
        mmc_bus_put(host);
        return -EINVAL;
    }

    if (host->bus_ops->power_save)
        ret = host->bus_ops->power_save(host);

    mmc_bus_put(host);

    mmc_power_off(host);

    return ret;
}
EXPORT_SYMBOL(mmc_power_save_host);

int mmc_power_restore_host(struct mmc_host *host)
{
    int ret;

#ifdef CONFIG_MMC_DEBUG
    pr_info("%s: %s: powering up\n", mmc_hostname(host), __func__);
#endif

    mmc_bus_get(host);

    if (!host->bus_ops || host->bus_dead || !host->bus_ops->power_restore) {
        mmc_bus_put(host);
        return -EINVAL;
    }

    mmc_power_up(host);
    ret = host->bus_ops->power_restore(host);

    mmc_bus_put(host);

    return ret;
}
EXPORT_SYMBOL(mmc_power_restore_host);

int mmc_card_awake(struct mmc_host *host)
{
    int err = -ENOSYS;

    if (host->caps2 & MMC_CAP2_NO_SLEEP_CMD)
        return 0;

    mmc_bus_get(host);

    if (host->bus_ops && !host->bus_dead && host->bus_ops->awake)
        err = host->bus_ops->awake(host);

    mmc_bus_put(host);

    return err;
}
EXPORT_SYMBOL(mmc_card_awake);

int mmc_card_sleep(struct mmc_host *host)
{
    int err = -ENOSYS;

    if (host->caps2 & MMC_CAP2_NO_SLEEP_CMD)
        return 0;

    mmc_bus_get(host);

    if (host->bus_ops && !host->bus_dead && host->bus_ops->sleep)
        err = host->bus_ops->sleep(host);

    mmc_bus_put(host);

    return err;
}
EXPORT_SYMBOL(mmc_card_sleep);

int mmc_card_can_sleep(struct mmc_host *host)
{
    struct mmc_card *card = host->card;

    if (card && mmc_card_mmc(card) && card->ext_csd.rev >= 3)
        return 1;
    return 0;
}
EXPORT_SYMBOL(mmc_card_can_sleep);

/*
 * Flush the cache to the non-volatile storage.
 */
int mmc_flush_cache(struct mmc_card *card)
{
    struct mmc_host *host = card->host;
    int err = 0;

    if (!(host->caps2 & MMC_CAP2_CACHE_CTRL))
        return err;

    if (mmc_card_mmc(card) &&
            (card->ext_csd.cache_size > 0) &&
            (card->ext_csd.cache_ctrl & 1)) {
        err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
                EXT_CSD_FLUSH_CACHE, 1, 0);
        if (err)
            pr_err("%s: cache flush error %d\n",
                    mmc_hostname(card->host), err);
    }

    return err;
}
EXPORT_SYMBOL(mmc_flush_cache);

/*
 * Turn the cache ON/OFF.
 * Turning the cache OFF shall trigger flushing of the data
 * to the non-volatile storage.
 */
int mmc_cache_ctrl(struct mmc_host *host, u8 enable)
{
    struct mmc_card *card = host->card;
    unsigned int timeout;
    int err = 0;

    if (!(host->caps2 & MMC_CAP2_CACHE_CTRL) ||
            mmc_card_is_removable(host))
        return err;

    mmc_claim_host(host);
    if (card && mmc_card_mmc(card) &&
            (card->ext_csd.cache_size > 0)) {
        enable = !!enable;

        if (card->ext_csd.cache_ctrl ^ enable) {
            timeout = enable ? card->ext_csd.generic_cmd6_time : 0;
            err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
                    EXT_CSD_CACHE_CTRL, enable, timeout);
            if (err)
                pr_err("%s: cache %s error %d\n",
                        mmc_hostname(card->host),
                        enable ? "on" : "off",
                        err);
            else
                card->ext_csd.cache_ctrl = enable;
        }
    }
    mmc_release_host(host);

    return err;
}
EXPORT_SYMBOL(mmc_cache_ctrl);

#ifdef CONFIG_PM

int mmc_suspend_host(struct mmc_host *host)
{
    int err = 0;

    cancel_delayed_work(&host->detect);
    mmc_flush_scheduled_work();

    err = mmc_cache_ctrl(host, 0);
    if (err)
        goto out;

    mmc_bus_get(host);
    if (host->bus_ops && !host->bus_dead) {
        if (host->bus_ops->suspend) {
            if (mmc_card_doing_bkops(host->card)) {
                err = mmc_stop_bkops(host->card);
                if (err)
                    goto out;
            }
            err = host->bus_ops->suspend(host);
        }

        if (err == -ENOSYS || !host->bus_ops->resume) {
            /*
             * We simply "remove" the card in this case.
             * It will be redetected on resume.  (Calling
             * bus_ops->remove() with a claimed host can
             * deadlock.)
             */
            if (host->bus_ops->remove)
                host->bus_ops->remove(host);
            mmc_claim_host(host);
            mmc_detach_bus(host);
            mmc_power_off(host);
            mmc_release_host(host);
            host->pm_flags = 0;
            err = 0;
        }
    }
    mmc_bus_put(host);

    if (!err && !mmc_card_keep_power(host))
        mmc_power_off(host);

out:
    return err;
}

EXPORT_SYMBOL(mmc_suspend_host);

int mmc_resume_host(struct mmc_host *host)
{
    int err = 0;

    mmc_bus_get(host);
    if (host->bus_ops && !host->bus_dead) {
        if (!mmc_card_keep_power(host)) {
            mmc_power_up(host);
            mmc_select_voltage(host, host->ocr);
            /*
             * Tell runtime PM core we just powered up the card,
             * since it still believes the card is powered off.
             * Note that currently runtime PM is only enabled
             * for SDIO cards that are MMC_CAP_POWER_OFF_CARD
             */
            if (mmc_card_sdio(host->card) &&
                (host->caps & MMC_CAP_POWER_OFF_CARD)) {
                pm_runtime_disable(&host->card->dev);
                pm_runtime_set_active(&host->card->dev);
                pm_runtime_enable(&host->card->dev);
            }
        }
        BUG_ON(!host->bus_ops->resume);
        err = host->bus_ops->resume(host);
        if (err) {
            pr_warning("%s: error %d during resume "
                        "(card was removed?)\n",
                        mmc_hostname(host), err);
            err = 0;
        }
    }
    host->pm_flags &= ~MMC_PM_KEEP_POWER;
    mmc_bus_put(host);

    return err;
}
EXPORT_SYMBOL(mmc_resume_host);

/* Do the card removal on suspend if card is assumed removeable
 * Do that in pm notifier while userspace isn't yet frozen, so we will be able
   to sync the card.
*/
int mmc_pm_notify(struct notifier_block *notify_block,
                    unsigned long mode, void *unused)
{
    struct mmc_host *host = container_of(
        notify_block, struct mmc_host, pm_notify);
    unsigned long flags;
    int err = 0;

    switch (mode) {
    case PM_HIBERNATION_PREPARE:
    case PM_SUSPEND_PREPARE:
        if (host->card && mmc_card_mmc(host->card) &&
            mmc_card_doing_bkops(host->card)) {
            err = mmc_stop_bkops(host->card);
            if (err) {
                pr_err("%s: didn't stop bkops\n",
                    mmc_hostname(host));
                return err;
            }
            mmc_card_clr_doing_bkops(host->card);
        }

        spin_lock_irqsave(&host->lock, flags);
        host->rescan_disable = 1;
        spin_unlock_irqrestore(&host->lock, flags);
        cancel_delayed_work_sync(&host->detect);

        if (!host->bus_ops || host->bus_ops->suspend)
            break;

        /* Calling bus_ops->remove() with a claimed host can deadlock */
        if (host->bus_ops->remove)
            host->bus_ops->remove(host);

        mmc_claim_host(host);
        mmc_detach_bus(host);
        mmc_power_off(host);
        mmc_release_host(host);
        host->pm_flags = 0;
        break;

    case PM_POST_SUSPEND:
    case PM_POST_HIBERNATION:
    case PM_POST_RESTORE:

        spin_lock_irqsave(&host->lock, flags);
        host->rescan_disable = 0;
        spin_unlock_irqrestore(&host->lock, flags);
        mmc_detect_change(host, 0);

    }

    return 0;
}
#endif

static int __init mmc_init(void)
{
    int ret;

    workqueue = alloc_ordered_workqueue("kmmcd", 0);
    if (!workqueue)
        return -ENOMEM;

    ret = mmc_register_bus();
    if (ret)
        goto destroy_workqueue;

    ret = mmc_register_host_class();
    if (ret)
        goto unregister_bus;

    ret = sdio_register_bus();
    if (ret)
        goto unregister_host_class;

    return 0;

unregister_host_class:
    mmc_unregister_host_class();
unregister_bus:
    mmc_unregister_bus();
destroy_workqueue:
    destroy_workqueue(workqueue);

    return ret;
}

static void __exit mmc_exit(void)
{
    sdio_unregister_bus();
    mmc_unregister_host_class();
    mmc_unregister_bus();
    destroy_workqueue(workqueue);
}

subsys_initcall(mmc_init);
module_exit(mmc_exit);

MODULE_LICENSE("GPL");