[linux-2.6-block.git] / drivers / mmc / core / core.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 *  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.
 */
#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/pm_runtime.h>
#include <linux/suspend.h>
#include <linux/fault-inject.h>
#include <linux/random.h>
#include <linux/slab.h>
#include <linux/of.h>

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

#define CREATE_TRACE_POINTS
#include <trace/events/mmc.h>

#include "core.h"
#include "card.h"
#include "crypto.h"
#include "bus.h"
#include "host.h"
#include "sdio_bus.h"
#include "pwrseq.h"

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

/* The max erase timeout, used when host->max_busy_timeout isn't specified */
#define MMC_ERASE_TIMEOUT_MS    (60 * 1000) /* 60 s */
#define SD_DISCARD_TIMEOUT_MS   (250)

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 to be disabled.
 */
bool use_spi_crc = 1;
module_param(use_spi_crc, bool, 0);

static int mmc_schedule_delayed_work(struct delayed_work *work,
                                     unsigned long delay)
{
        /*
         * We use the system_freezable_wq, because of two reasons.
         * First, it allows several works (not the same work item) to be
         * executed simultaneously. Second, the queue becomes frozen when
         * userspace becomes frozen during system PM.
         */
        return queue_delayed_work(system_freezable_wq, work, delay);
}

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

        data->error = data_errors[get_random_u32_below(ARRAY_SIZE(data_errors))];
        data->bytes_xfered = get_random_u32_below(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 */

static inline void mmc_complete_cmd(struct mmc_request *mrq)
{
        if (mrq->cap_cmd_during_tfr && !completion_done(&mrq->cmd_completion))
                complete_all(&mrq->cmd_completion);
}

void mmc_command_done(struct mmc_host *host, struct mmc_request *mrq)
{
        if (!mrq->cap_cmd_during_tfr)
                return;

        mmc_complete_cmd(mrq);

        pr_debug("%s: cmd done, tfr ongoing (CMD%u)\n",
                 mmc_hostname(host), mrq->cmd->opcode);
}
EXPORT_SYMBOL(mmc_command_done);

/**
 *      mmc_request_done - finish processing an MMC request
 *      @host: MMC host which completed request
 *      @mrq: MMC request which request
 *
 *      MMC drivers should call this function when they have completed
 *      their processing of a request.
 */
void mmc_request_done(struct mmc_host *host, struct mmc_request *mrq)
{
        struct mmc_command *cmd = mrq->cmd;
        int err = cmd->error;

        /* Flag re-tuning needed on CRC errors */
        if (!mmc_op_tuning(cmd->opcode) &&
            !host->retune_crc_disable &&
            (err == -EILSEQ || (mrq->sbc && mrq->sbc->error == -EILSEQ) ||
            (mrq->data && mrq->data->error == -EILSEQ) ||
            (mrq->stop && mrq->stop->error == -EILSEQ)))
                mmc_retune_needed(host);

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

        if (host->ongoing_mrq == mrq)
                host->ongoing_mrq = NULL;

        mmc_complete_cmd(mrq);

        trace_mmc_request_done(host, mrq);

        /*
         * We list various conditions for the command to be considered
         * properly done:
         *
         * - There was no error, OK fine then
         * - We are not doing some kind of retry
         * - The card was removed (...so just complete everything no matter
         *   if there are errors or retries)
         */
        if (!err || !cmd->retries || mmc_card_removed(host->card)) {
                mmc_should_fail_request(host, mrq);

                if (!host->ongoing_mrq)
                        led_trigger_event(host->led, LED_OFF);

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

                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]);
                }
        }
        /*
         * Request starter must handle retries - see
         * mmc_wait_for_req_done().
         */
        if (mrq->done)
                mrq->done(mrq);
}

EXPORT_SYMBOL(mmc_request_done);

static void __mmc_start_request(struct mmc_host *host, struct mmc_request *mrq)
{
        int err;

        /* Assumes host controller has been runtime resumed by mmc_claim_host */
        err = mmc_retune(host);
        if (err) {
                mrq->cmd->error = err;
                mmc_request_done(host, mrq);
                return;
        }

        /*
         * For sdio rw commands we must wait for card busy otherwise some
         * sdio devices won't work properly.
         * And bypass I/O abort, reset and bus suspend operations.
         */
        if (sdio_is_io_busy(mrq->cmd->opcode, mrq->cmd->arg) &&
            host->ops->card_busy) {
                int tries = 500; /* Wait aprox 500ms at maximum */

                while (host->ops->card_busy(host) && --tries)
                        mmc_delay(1);

                if (tries == 0) {
                        mrq->cmd->error = -EBUSY;
                        mmc_request_done(host, mrq);
                        return;
                }
        }

        if (mrq->cap_cmd_during_tfr) {
                host->ongoing_mrq = mrq;
                /*
                 * Retry path could come through here without having waiting on
                 * cmd_completion, so ensure it is reinitialised.
                 */
                reinit_completion(&mrq->cmd_completion);
        }

        trace_mmc_request_start(host, mrq);

        if (host->cqe_on)
                host->cqe_ops->cqe_off(host);

        host->ops->request(host, mrq);
}

static void mmc_mrq_pr_debug(struct mmc_host *host, struct mmc_request *mrq,
                             bool cqe)
{
        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);
        }

        if (mrq->cmd) {
                pr_debug("%s: starting %sCMD%u arg %08x flags %08x\n",
                         mmc_hostname(host), cqe ? "CQE direct " : "",
                         mrq->cmd->opcode, mrq->cmd->arg, mrq->cmd->flags);
        } else if (cqe) {
                pr_debug("%s: starting CQE transfer for tag %d blkaddr %u\n",
                         mmc_hostname(host), mrq->tag, mrq->data->blk_addr);
        }

        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);
        }
}

static int mmc_mrq_prep(struct mmc_host *host, struct mmc_request *mrq)
{
        unsigned int i, sz = 0;
        struct scatterlist *sg;

        if (mrq->cmd) {
                mrq->cmd->error = 0;
                mrq->cmd->mrq = mrq;
                mrq->cmd->data = mrq->data;
        }
        if (mrq->sbc) {
                mrq->sbc->error = 0;
                mrq->sbc->mrq = mrq;
        }
        if (mrq->data) {
                if (mrq->data->blksz > host->max_blk_size ||
                    mrq->data->blocks > host->max_blk_count ||
                    mrq->data->blocks * mrq->data->blksz > host->max_req_size)
                        return -EINVAL;

                for_each_sg(mrq->data->sg, sg, mrq->data->sg_len, i)
                        sz += sg->length;
                if (sz != mrq->data->blocks * mrq->data->blksz)
                        return -EINVAL;

                mrq->data->error = 0;
                mrq->data->mrq = mrq;
                if (mrq->stop) {
                        mrq->data->stop = mrq->stop;
                        mrq->stop->error = 0;
                        mrq->stop->mrq = mrq;
                }
        }

        return 0;
}

int mmc_start_request(struct mmc_host *host, struct mmc_request *mrq)
{
        int err;

        if (mrq->cmd->has_ext_addr)
                mmc_send_ext_addr(host, mrq->cmd->ext_addr);

        init_completion(&mrq->cmd_completion);

        mmc_retune_hold(host);

        if (mmc_card_removed(host->card))
                return -ENOMEDIUM;

        mmc_mrq_pr_debug(host, mrq, false);

        WARN_ON(!host->claimed);

        err = mmc_mrq_prep(host, mrq);
        if (err)
                return err;

        if (host->uhs2_sd_tran)
                mmc_uhs2_prepare_cmd(host, mrq);

        led_trigger_event(host->led, LED_FULL);
        __mmc_start_request(host, mrq);

        return 0;
}
EXPORT_SYMBOL(mmc_start_request);

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

static inline void mmc_wait_ongoing_tfr_cmd(struct mmc_host *host)
{
        struct mmc_request *ongoing_mrq = READ_ONCE(host->ongoing_mrq);

        /*
         * If there is an ongoing transfer, wait for the command line to become
         * available.
         */
        if (ongoing_mrq && !completion_done(&ongoing_mrq->cmd_completion))
                wait_for_completion(&ongoing_mrq->cmd_completion);
}

static int __mmc_start_req(struct mmc_host *host, struct mmc_request *mrq)
{
        int err;

        mmc_wait_ongoing_tfr_cmd(host);

        init_completion(&mrq->completion);
        mrq->done = mmc_wait_done;

        err = mmc_start_request(host, mrq);
        if (err) {
                mrq->cmd->error = err;
                mmc_complete_cmd(mrq);
                complete(&mrq->completion);
        }

        return err;
}

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;

                mmc_retune_recheck(host);

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

        mmc_retune_release(host);
}
EXPORT_SYMBOL(mmc_wait_for_req_done);

/*
 * mmc_cqe_start_req - Start a CQE request.
 * @host: MMC host to start the request
 * @mrq: request to start
 *
 * Start the request, re-tuning if needed and it is possible. Returns an error
 * code if the request fails to start or -EBUSY if CQE is busy.
 */
int mmc_cqe_start_req(struct mmc_host *host, struct mmc_request *mrq)
{
        int err;

        /*
         * CQE cannot process re-tuning commands. Caller must hold retuning
         * while CQE is in use.  Re-tuning can happen here only when CQE has no
         * active requests i.e. this is the first.  Note, re-tuning will call
         * ->cqe_off().
         */
        err = mmc_retune(host);
        if (err)
                goto out_err;

        mrq->host = host;

        mmc_mrq_pr_debug(host, mrq, true);

        err = mmc_mrq_prep(host, mrq);
        if (err)
                goto out_err;

        if (host->uhs2_sd_tran)
                mmc_uhs2_prepare_cmd(host, mrq);

        err = host->cqe_ops->cqe_request(host, mrq);
        if (err)
                goto out_err;

        trace_mmc_request_start(host, mrq);

        return 0;

out_err:
        if (mrq->cmd) {
                pr_debug("%s: failed to start CQE direct CMD%u, error %d\n",
                         mmc_hostname(host), mrq->cmd->opcode, err);
        } else {
                pr_debug("%s: failed to start CQE transfer for tag %d, error %d\n",
                         mmc_hostname(host), mrq->tag, err);
        }
        return err;
}
EXPORT_SYMBOL(mmc_cqe_start_req);

/**
 *      mmc_cqe_request_done - CQE has finished processing an MMC request
 *      @host: MMC host which completed request
 *      @mrq: MMC request which completed
 *
 *      CQE drivers should call this function when they have completed
 *      their processing of a request.
 */
void mmc_cqe_request_done(struct mmc_host *host, struct mmc_request *mrq)
{
        mmc_should_fail_request(host, mrq);

        /* Flag re-tuning needed on CRC errors */
        if ((mrq->cmd && mrq->cmd->error == -EILSEQ) ||
            (mrq->data && mrq->data->error == -EILSEQ))
                mmc_retune_needed(host);

        trace_mmc_request_done(host, mrq);

        if (mrq->cmd) {
                pr_debug("%s: CQE req done (direct CMD%u): %d\n",
                         mmc_hostname(host), mrq->cmd->opcode, mrq->cmd->error);
        } else {
                pr_debug("%s: CQE transfer done tag %d\n",
                         mmc_hostname(host), mrq->tag);
        }

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

        mrq->done(mrq);
}
EXPORT_SYMBOL(mmc_cqe_request_done);

/**
 *      mmc_cqe_post_req - CQE post process of a completed MMC request
 *      @host: MMC host
 *      @mrq: MMC request to be processed
 */
void mmc_cqe_post_req(struct mmc_host *host, struct mmc_request *mrq)
{
        if (host->cqe_ops->cqe_post_req)
                host->cqe_ops->cqe_post_req(host, mrq);
}
EXPORT_SYMBOL(mmc_cqe_post_req);

/* Arbitrary 1 second timeout */
#define MMC_CQE_RECOVERY_TIMEOUT        1000

/*
 * mmc_cqe_recovery - Recover from CQE errors.
 * @host: MMC host to recover
 *
 * Recovery consists of stopping CQE, stopping eMMC, discarding the queue
 * in eMMC, and discarding the queue in CQE. CQE must call
 * mmc_cqe_request_done() on all requests. An error is returned if the eMMC
 * fails to discard its queue.
 */
int mmc_cqe_recovery(struct mmc_host *host)
{
        struct mmc_command cmd;
        int err;

        mmc_retune_hold_now(host);

        /*
         * Recovery is expected seldom, if at all, but it reduces performance,
         * so make sure it is not completely silent.
         */
        pr_warn("%s: running CQE recovery\n", mmc_hostname(host));

        host->cqe_ops->cqe_recovery_start(host);

        memset(&cmd, 0, sizeof(cmd));
        cmd.opcode       = MMC_STOP_TRANSMISSION;
        cmd.flags        = MMC_RSP_R1B_NO_CRC | MMC_CMD_AC; /* Ignore CRC */
        cmd.busy_timeout = MMC_CQE_RECOVERY_TIMEOUT;
        mmc_wait_for_cmd(host, &cmd, MMC_CMD_RETRIES);

        mmc_poll_for_busy(host->card, MMC_CQE_RECOVERY_TIMEOUT, true, MMC_BUSY_IO);

        memset(&cmd, 0, sizeof(cmd));
        cmd.opcode       = MMC_CMDQ_TASK_MGMT;
        cmd.arg          = 1; /* Discard entire queue */
        cmd.flags        = MMC_RSP_R1B_NO_CRC | MMC_CMD_AC; /* Ignore CRC */
        cmd.busy_timeout = MMC_CQE_RECOVERY_TIMEOUT;
        err = mmc_wait_for_cmd(host, &cmd, MMC_CMD_RETRIES);

        host->cqe_ops->cqe_recovery_finish(host);

        if (err)
                err = mmc_wait_for_cmd(host, &cmd, MMC_CMD_RETRIES);

        mmc_retune_release(host);

        return err;
}
EXPORT_SYMBOL(mmc_cqe_recovery);

/**
 *      mmc_is_req_done - Determine if a 'cap_cmd_during_tfr' request is done
 *      @host: MMC host
 *      @mrq: MMC request
 *
 *      mmc_is_req_done() is used with requests that have
 *      mrq->cap_cmd_during_tfr = true. mmc_is_req_done() must be called after
 *      starting a request and before waiting for it to complete. That is,
 *      either in between calls to mmc_start_req(), or after mmc_wait_for_req()
 *      and before mmc_wait_for_req_done(). If it is called at other times the
 *      result is not meaningful.
 */
bool mmc_is_req_done(struct mmc_host *host, struct mmc_request *mrq)
{
        return completion_done(&mrq->completion);
}
EXPORT_SYMBOL(mmc_is_req_done);

/**
 *      mmc_wait_for_req - start a request and wait for completion
 *      @host: MMC host to start command
 *      @mrq: MMC request to start
 *
 *      Start a new MMC custom command request for a host, and wait
 *      for the command to complete. In the case of 'cap_cmd_during_tfr'
 *      requests, the transfer is ongoing and the caller can issue further
 *      commands that do not use the data lines, and then wait by calling
 *      mmc_wait_for_req_done().
 *      Does not attempt to parse the response.
 */
void mmc_wait_for_req(struct mmc_host *host, struct mmc_request *mrq)
{
        __mmc_start_req(host, mrq);

        if (!mrq->cap_cmd_during_tfr)
                mmc_wait_for_req_done(host, mrq);
}
EXPORT_SYMBOL(mmc_wait_for_req);

/**
 *      mmc_wait_for_cmd - start a command and wait for completion
 *      @host: MMC host to start command
 *      @cmd: MMC command to start
 *      @retries: maximum number of retries
 *
 *      Start a new MMC command for a host, and wait for the command
 *      to complete.  Return any error that occurred while the command
 *      was executing.  Do not attempt to parse the response.
 */
int mmc_wait_for_cmd(struct mmc_host *host, struct mmc_command *cmd, int retries)
{
        struct mmc_request mrq = {};

        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);

/**
 *      mmc_set_data_timeout - set the timeout for a data command
 *      @data: data phase for command
 *      @card: the MMC card associated with the data transfer
 *
 *      Computes the data timeout parameters according to the
 *      correct algorithm given the card type.
 */
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.taac_ns * mult;
        data->timeout_clks = card->csd.taac_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 (card->host->ios.clock)
                        timeout_us += data->timeout_clks * 1000 /
                                (card->host->ios.clock / 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) {
                        data->timeout_ns = limit_us * 1000;
                        data->timeout_clks = 0;
                }

                /* assign limit value if invalid */
                if (timeout_us == 0)
                        data->timeout_ns = limit_us * 1000;
        }

        /*
         * 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, 600ms 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 = 600000000;
                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);

/*
 * Allow claiming an already claimed host if the context is the same or there is
 * no context but the task is the same.
 */
static inline bool mmc_ctx_matches(struct mmc_host *host, struct mmc_ctx *ctx,
                                   struct task_struct *task)
{
        return host->claimer == ctx ||
               (!ctx && task && host->claimer->task == task);
}

static inline void mmc_ctx_set_claimer(struct mmc_host *host,
                                       struct mmc_ctx *ctx,
                                       struct task_struct *task)
{
        if (!host->claimer) {
                if (ctx)
                        host->claimer = ctx;
                else
                        host->claimer = &host->default_ctx;
        }
        if (task)
                host->claimer->task = task;
}

/**
 *      __mmc_claim_host - exclusively claim a host
 *      @host: mmc host to claim
 *      @ctx: context that claims the host or NULL in which case the default
 *      context will be used
 *      @abort: whether or not the operation should be aborted
 *
 *      Claim a host for a set of operations.  If @abort is non null and
 *      dereference a non-zero value then this will return prematurely with
 *      that non-zero value without acquiring the lock.  Returns zero
 *      with the lock held otherwise.
 */
int __mmc_claim_host(struct mmc_host *host, struct mmc_ctx *ctx,
                     atomic_t *abort)
{
        struct task_struct *task = ctx ? NULL : current;
        DECLARE_WAITQUEUE(wait, current);
        unsigned long flags;
        int stop;
        bool pm = false;

        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 || mmc_ctx_matches(host, ctx, task))
                        break;
                spin_unlock_irqrestore(&host->lock, flags);
                schedule();
                spin_lock_irqsave(&host->lock, flags);
        }
        set_current_state(TASK_RUNNING);
        if (!stop) {
                host->claimed = 1;
                mmc_ctx_set_claimer(host, ctx, task);
                host->claim_cnt += 1;
                if (host->claim_cnt == 1)
                        pm = true;
        } else
                wake_up(&host->wq);
        spin_unlock_irqrestore(&host->lock, flags);
        remove_wait_queue(&host->wq, &wait);

        if (pm)
                pm_runtime_get_sync(mmc_dev(host));

        return stop;
}
EXPORT_SYMBOL(__mmc_claim_host);

/**
 *      mmc_release_host - release a host
 *      @host: mmc host to release
 *
 *      Release a MMC host, allowing others to claim the host
 *      for their operations.
 */
void mmc_release_host(struct mmc_host *host)
{
        unsigned long flags;

        WARN_ON(!host->claimed);

        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->task = NULL;
                host->claimer = NULL;
                spin_unlock_irqrestore(&host->lock, flags);
                wake_up(&host->wq);
                pm_runtime_mark_last_busy(mmc_dev(host));
                if (host->caps & MMC_CAP_SYNC_RUNTIME_PM)
                        pm_runtime_put_sync_suspend(mmc_dev(host));
                else
                        pm_runtime_put_autosuspend(mmc_dev(host));
        }
}
EXPORT_SYMBOL(mmc_release_host);

/*
 * This is a helper function, which fetches a runtime pm reference for the
 * card device and also claims the host.
 */
void mmc_get_card(struct mmc_card *card, struct mmc_ctx *ctx)
{
        pm_runtime_get_sync(&card->dev);
        __mmc_claim_host(card->host, ctx, NULL);
}
EXPORT_SYMBOL(mmc_get_card);

/*
 * This is a helper function, which releases the host and drops the runtime
 * pm reference for the card device.
 */
void mmc_put_card(struct mmc_card *card, struct mmc_ctx *ctx)
{
        struct mmc_host *host = card->host;

        WARN_ON(ctx && host->claimer != ctx);

        mmc_release_host(host);
        pm_runtime_mark_last_busy(&card->dev);
        pm_runtime_put_autosuspend(&card->dev);
}
EXPORT_SYMBOL(mmc_put_card);

/*
 * 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,
                 1 << ios->bus_width, ios->timing);

        host->ops->set_ios(host, ios);
}

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

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

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

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

int mmc_execute_tuning(struct mmc_card *card)
{
        struct mmc_host *host = card->host;
        u32 opcode;
        int err;

        if (!host->ops->execute_tuning)
                return 0;

        if (host->cqe_on)
                host->cqe_ops->cqe_off(host);

        if (mmc_card_mmc(card))
                opcode = MMC_SEND_TUNING_BLOCK_HS200;
        else
                opcode = MMC_SEND_TUNING_BLOCK;

        err = host->ops->execute_tuning(host, opcode);
        if (!err) {
                mmc_retune_clear(host);
                mmc_retune_enable(host);
                return 0;
        }

        /* Only print error when we don't check for card removal */
        if (!host->detect_change) {
                pr_err("%s: tuning execution failed: %d\n",
                        mmc_hostname(host), err);
                mmc_debugfs_err_stats_inc(host, MMC_ERR_TUNING);
        }

        return err;
}

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

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

/*
 * Set initial state after a power cycle or a hw_reset.
 */
void mmc_set_initial_state(struct mmc_host *host)
{
        if (host->cqe_on)
                host->cqe_ops->cqe_off(host);

        mmc_retune_disable(host);

        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.bus_width = MMC_BUS_WIDTH_1;
        host->ios.timing = MMC_TIMING_LEGACY;
        host->ios.drv_type = 0;
        host->ios.enhanced_strobe = false;

        /*
         * Make sure we are in non-enhanced strobe mode before we
         * actually enable it in ext_csd.
         */
        if ((host->caps2 & MMC_CAP2_HS400_ES) &&
             host->ops->hs400_enhanced_strobe)
                host->ops->hs400_enhanced_strobe(host, &host->ios);

        mmc_set_ios(host);

        mmc_crypto_set_initial_state(host);
}

/**
 * mmc_vdd_to_ocrbitnum - Convert a voltage to the OCR bit number
 * @vdd:        voltage (mV)
 * @low_bits:   prefer low bits in boundary cases
 *
 * This function returns the OCR bit number according to the provided @vdd
 * value. If conversion is not possible a negative errno value returned.
 *
 * Depending on the @low_bits flag the function prefers low or high OCR bits
 * on boundary voltages. For example,
 * with @low_bits = true, 3300 mV translates to ilog2(MMC_VDD_32_33);
 * with @low_bits = false, 3300 mV translates to ilog2(MMC_VDD_33_34);
 *
 * Any value in the [1951:1999] range translates to the ilog2(MMC_VDD_20_21).
 */
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;
}

/**
 * mmc_vddrange_to_ocrmask - Convert a voltage range to the OCR mask
 * @vdd_min:    minimum voltage value (mV)
 * @vdd_max:    maximum voltage value (mV)
 *
 * This function returns the OCR mask bits according to the provided @vdd_min
 * and @vdd_max values. If conversion is not possible the function returns 0.
 *
 * Notes wrt boundary cases:
 * This function sets the OCR bits for all boundary voltages, for example
 * [3300:3400] range is translated to MMC_VDD_32_33 | MMC_VDD_33_34 |
 * MMC_VDD_34_35 mask.
 */
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;
}

static int mmc_of_get_func_num(struct device_node *node)
{
        u32 reg;
        int ret;

        ret = of_property_read_u32(node, "reg", &reg);
        if (ret < 0)
                return ret;

        return reg;
}

struct device_node *mmc_of_find_child_device(struct mmc_host *host,
                unsigned func_num)
{
        struct device_node *node;

        if (!host->parent || !host->parent->of_node)
                return NULL;

        for_each_child_of_node(host->parent->of_node, node) {
                if (mmc_of_get_func_num(node) == func_num)
                        return node;
        }

        return NULL;
}

/*
 * 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;

        /*
         * Sanity check the voltages that the card claims to
         * support.
         */
        if (ocr & 0x7F) {
                dev_warn(mmc_dev(host),
                "card claims to support voltages below defined range\n");
                ocr &= ~0x7F;
        }

        ocr &= host->ocr_avail;
        if (!ocr) {
                dev_warn(mmc_dev(host), "no support for card's volts\n");
                return 0;
        }

        if (!mmc_card_uhs2(host) && host->caps2 & MMC_CAP2_FULL_PWR_CYCLE) {
                bit = ffs(ocr) - 1;
                ocr &= 3 << bit;
                mmc_power_cycle(host, ocr);
        } else {
                bit = fls(ocr) - 1;
                /*
                 * The bit variable represents the highest voltage bit set in
                 * the OCR register.
                 * To keep a range of 2 values (e.g. 3.2V/3.3V and 3.3V/3.4V),
                 * we must shift the mask '3' with (bit - 1).
                 */
                ocr &= 3 << (bit - 1);
                if (bit != host->ios.vdd)
                        dev_warn(mmc_dev(host), "exceeding card's volts\n");
        }

        return ocr;
}

int mmc_set_signal_voltage(struct mmc_host *host, int signal_voltage)
{
        int err = 0;
        int old_signal_voltage = host->ios.signal_voltage;

        host->ios.signal_voltage = signal_voltage;
        if (host->ops->start_signal_voltage_switch)
                err = host->ops->start_signal_voltage_switch(host, &host->ios);

        if (err)
                host->ios.signal_voltage = old_signal_voltage;

        return err;

}

void mmc_set_initial_signal_voltage(struct mmc_host *host)
{
        /* Try to set signal voltage to 3.3V but fall back to 1.8v or 1.2v */
        if (!mmc_set_signal_voltage(host, MMC_SIGNAL_VOLTAGE_330))
                dev_dbg(mmc_dev(host), "Initial signal voltage of 3.3v\n");
        else if (!mmc_set_signal_voltage(host, MMC_SIGNAL_VOLTAGE_180))
                dev_dbg(mmc_dev(host), "Initial signal voltage of 1.8v\n");
        else if (!mmc_set_signal_voltage(host, MMC_SIGNAL_VOLTAGE_120))
                dev_dbg(mmc_dev(host), "Initial signal voltage of 1.2v\n");
}

int mmc_host_set_uhs_voltage(struct mmc_host *host)
{
        u32 clock;

        /*
         * During a signal voltage level switch, the clock must be gated
         * for 5 ms according to the SD spec
         */
        clock = host->ios.clock;
        host->ios.clock = 0;
        mmc_set_ios(host);

        if (mmc_set_signal_voltage(host, MMC_SIGNAL_VOLTAGE_180))
                return -EAGAIN;

        /* Keep clock gated for at least 10 ms, though spec only says 5 ms */
        mmc_delay(10);
        host->ios.clock = clock;
        mmc_set_ios(host);

        return 0;
}

int mmc_set_uhs_voltage(struct mmc_host *host, u32 ocr)
{
        struct mmc_command cmd = {};
        int err = 0;

        /*
         * If we cannot switch voltages, return failure so the caller
         * can continue without UHS mode
         */
        if (!host->ops->start_signal_voltage_switch)
                return -EPERM;
        if (!host->ops->card_busy)
                pr_warn("%s: cannot verify signal voltage switch\n",
                        mmc_hostname(host));

        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)
                goto power_cycle;

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

        /*
         * The card should drive cmd and dat[0:3] low immediately
         * after the response of cmd11, but wait 1 ms to be sure
         */
        mmc_delay(1);
        if (host->ops->card_busy && !host->ops->card_busy(host)) {
                err = -EAGAIN;
                goto power_cycle;
        }

        if (mmc_host_set_uhs_voltage(host)) {
                /*
                 * Voltages may not have been switched, but we've already
                 * sent CMD11, so a power cycle is required anyway
                 */
                err = -EAGAIN;
                goto power_cycle;
        }

        /* Wait for at least 1 ms according to spec */
        mmc_delay(1);

        /*
         * Failure to switch is indicated by the card holding
         * dat[0:3] low
         */
        if (host->ops->card_busy && host->ops->card_busy(host))
                err = -EAGAIN;

power_cycle:
        if (err) {
                pr_debug("%s: Signal voltage switch failed, "
                        "power cycling card\n", mmc_hostname(host));
                mmc_power_cycle(host, ocr);
        }

        return err;
}

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

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

int mmc_select_drive_strength(struct mmc_card *card, unsigned int max_dtr,
                              int card_drv_type, int *drv_type)
{
        struct mmc_host *host = card->host;
        int host_drv_type = SD_DRIVER_TYPE_B;

        *drv_type = 0;

        if (!host->ops->select_drive_strength)
                return 0;

        /* Use SD definition of driver strength for hosts */
        if (host->caps & MMC_CAP_DRIVER_TYPE_A)
                host_drv_type |= SD_DRIVER_TYPE_A;

        if (host->caps & MMC_CAP_DRIVER_TYPE_C)
                host_drv_type |= SD_DRIVER_TYPE_C;

        if (host->caps & MMC_CAP_DRIVER_TYPE_D)
                host_drv_type |= SD_DRIVER_TYPE_D;

        /*
         * The drive strength that the hardware can support
         * depends on the board design.  Pass the appropriate
         * information and let the hardware specific code
         * return what is possible given the options
         */
        return host->ops->select_drive_strength(card, max_dtr,
                                                host_drv_type,
                                                card_drv_type,
                                                drv_type);
}

/*
 * 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.
 */
void mmc_power_up(struct mmc_host *host, u32 ocr)
{
        if (host->ios.power_mode == MMC_POWER_ON)
                return;

        mmc_pwrseq_pre_power_on(host);

        host->ios.vdd = fls(ocr) - 1;
        host->ios.power_mode = MMC_POWER_UP;
        /* Set initial state and call mmc_set_ios */
        mmc_set_initial_state(host);

        mmc_set_initial_signal_voltage(host);

        /*
         * This delay should be sufficient to allow the power supply
         * to reach the minimum voltage.
         */
        mmc_delay(host->ios.power_delay_ms);

        mmc_pwrseq_post_power_on(host);

        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(host->ios.power_delay_ms);
}

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

        mmc_pwrseq_power_off(host);

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

        host->ios.power_mode = MMC_POWER_OFF;
        /* Set initial state and call mmc_set_ios */
        mmc_set_initial_state(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);
}

void mmc_power_cycle(struct mmc_host *host, u32 ocr)
{
        mmc_power_off(host);
        /* Wait at least 1 ms according to SD spec */
        mmc_delay(1);
        mmc_power_up(host, ocr);
}

/*
 * 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)
{
        host->bus_ops = ops;
}

/*
 * Remove the current bus handler from a host.
 */
void mmc_detach_bus(struct mmc_host *host)
{
        host->bus_ops = NULL;
}

void _mmc_detect_change(struct mmc_host *host, unsigned long delay, bool cd_irq)
{
        /*
         * Prevent system sleep for 5s to allow user space to consume the
         * corresponding uevent. This is especially useful, when CD irq is used
         * as a system wakeup, but doesn't hurt in other cases.
         */
        if (cd_irq && !(host->caps & MMC_CAP_NEEDS_POLL))
                __pm_wakeup_event(host->ws, 5000);

        host->detect_change = 1;
        mmc_schedule_delayed_work(&host->detect, delay);
}

/**
 *      mmc_detect_change - process change of state on a MMC socket
 *      @host: host which changed state.
 *      @delay: optional delay to wait before detection (jiffies)
 *
 *      MMC drivers should call this when they detect a card has been
 *      inserted or removed. The MMC layer will confirm that any
 *      present card is still functional, and initialize any newly
 *      inserted.
 */
void mmc_detect_change(struct mmc_host *host, unsigned long delay)
{
        _mmc_detect_change(host, delay, true);
}
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, have a stab at ai good value and 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. Also note, erase_size is already set to
         * High Capacity Erase Size if available when this function is called.
         */
        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->erase_size) {
                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;
                }
        } else
                card->pref_erase = 0;
}

static bool is_trim_arg(unsigned int arg)
{
        return (arg & MMC_TRIM_OR_DISCARD_ARGS) && arg != MMC_DISCARD_ARG;
}

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.taac_clks * mult;
                unsigned int timeout_us;

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

        /* for DISCARD none of the below calculation applies.
         * the busy timeout is 250msec per discard command.
         */
        if (arg == SD_DISCARD_ARG)
                return SD_DISCARD_TIMEOUT_MS;

        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, sector_t from,
                        sector_t to, unsigned int arg)
{
        struct mmc_command cmd = {};
        unsigned int qty = 0, busy_timeout = 0;
        bool use_r1b_resp;
        int err;

        mmc_retune_hold(card->host);

        /*
         * 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 += (mmc_sector_div(to, card->erase_size) -
                        mmc_sector_div(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;

        if (mmc_card_ult_capacity(card)) {
                cmd.ext_addr = from >> 32;
                cmd.has_ext_addr = true;
        }

        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;

        if (mmc_card_ult_capacity(card)) {
                cmd.ext_addr = to >> 32;
                cmd.has_ext_addr = true;
        }

        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;
        busy_timeout = mmc_erase_timeout(card, arg, qty);
        use_r1b_resp = mmc_prepare_busy_cmd(card->host, &cmd, busy_timeout);

        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;

        /*
         * In case of when R1B + MMC_CAP_WAIT_WHILE_BUSY is used, the polling
         * shall be avoided.
         */
        if ((card->host->caps & MMC_CAP_WAIT_WHILE_BUSY) && use_r1b_resp)
                goto out;

        /* Let's poll to find out when the erase operation completes. */
        err = mmc_poll_for_busy(card, busy_timeout, false, MMC_BUSY_ERASE);

out:
        mmc_retune_release(card->host);
        return err;
}

static unsigned int mmc_align_erase_size(struct mmc_card *card,
                                         sector_t *from,
                                         sector_t *to,
                                         unsigned int nr)
{
        sector_t from_new = *from;
        unsigned int nr_new = nr, rem;

        /*
         * When the 'card->erase_size' is power of 2, we can use round_up/down()
         * to align the erase size efficiently.
         */
        if (is_power_of_2(card->erase_size)) {
                sector_t temp = from_new;

                from_new = round_up(temp, card->erase_size);
                rem = from_new - temp;

                if (nr_new > rem)
                        nr_new -= rem;
                else
                        return 0;

                nr_new = round_down(nr_new, card->erase_size);
        } else {
                rem = mmc_sector_mod(from_new, card->erase_size);
                if (rem) {
                        rem = card->erase_size - rem;
                        from_new += rem;
                        if (nr_new > rem)
                                nr_new -= rem;
                        else
                                return 0;
                }

                rem = nr_new % card->erase_size;
                if (rem)
                        nr_new -= rem;
        }

        if (nr_new == 0)
                return 0;

        *to = from_new + nr_new;
        *from = from_new;

        return nr_new;
}

/**
 * mmc_erase - erase sectors.
 * @card: card to erase
 * @from: first sector to erase
 * @nr: number of sectors to erase
 * @arg: erase command argument
 *
 * Caller must claim host before calling this function.
 */
int mmc_erase(struct mmc_card *card, sector_t from, unsigned int nr,
              unsigned int arg)
{
        unsigned int rem;
        sector_t to = from + nr;

        int err;

        if (!(card->csd.cmdclass & CCC_ERASE))
                return -EOPNOTSUPP;

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

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

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

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

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

        if (arg == MMC_ERASE_ARG)
                nr = mmc_align_erase_size(card, &from, &to, nr);

        if (nr == 0)
                return 0;

        if (to <= from)
                return -EINVAL;

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

        /*
         * Special case where only one erase-group fits in the timeout budget:
         * If the region crosses an erase-group boundary on this particular
         * case, we will be trimming more than one erase-group which, does not
         * fit in the timeout budget of the controller, so we need to split it
         * and call mmc_do_erase() twice if necessary. This special case is
         * identified by the card->eg_boundary flag.
         */
        rem = card->erase_size - mmc_sector_mod(from, card->erase_size);
        if ((arg & MMC_TRIM_OR_DISCARD_ARGS) && card->eg_boundary && nr > rem) {
                err = mmc_do_erase(card, from, from + rem - 1, arg);
                from += rem;
                if ((err) || (to <= from))
                        return err;
        }

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

bool mmc_card_can_erase(struct mmc_card *card)
{
        return (card->csd.cmdclass & CCC_ERASE && card->erase_size);
}
EXPORT_SYMBOL(mmc_card_can_erase);

bool mmc_card_can_trim(struct mmc_card *card)
{
        return ((card->ext_csd.sec_feature_support & EXT_CSD_SEC_GB_CL_EN) &&
                (!(card->quirks & MMC_QUIRK_TRIM_BROKEN)));
}
EXPORT_SYMBOL(mmc_card_can_trim);

bool mmc_card_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.
         */
        return (card->ext_csd.feature_support & MMC_DISCARD_FEATURE);
}
EXPORT_SYMBOL(mmc_card_can_discard);

bool mmc_card_can_sanitize(struct mmc_card *card)
{
        if (!mmc_card_can_trim(card) && !mmc_card_can_erase(card))
                return false;
        if (card->ext_csd.sec_feature_support & EXT_CSD_SEC_SANITIZE)
                return true;
        return false;
}

bool mmc_card_can_secure_erase_trim(struct mmc_card *card)
{
        return ((card->ext_csd.sec_feature_support & EXT_CSD_SEC_ER_EN) &&
                !(card->quirks & MMC_QUIRK_SEC_ERASE_TRIM_BROKEN));
}
EXPORT_SYMBOL(mmc_card_can_secure_erase_trim);

int mmc_erase_group_aligned(struct mmc_card *card, sector_t from,
                            unsigned int nr)
{
        if (!card->erase_size)
                return 0;
        if (mmc_sector_mod(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, min_qty, timeout;
        unsigned int last_timeout = 0;
        unsigned int max_busy_timeout = host->max_busy_timeout ?
                        host->max_busy_timeout : MMC_ERASE_TIMEOUT_MS;

        if (card->erase_shift) {
                max_qty = UINT_MAX >> card->erase_shift;
                min_qty = card->pref_erase >> card->erase_shift;
        } else if (mmc_card_sd(card)) {
                max_qty = UINT_MAX;
                min_qty = card->pref_erase;
        } else {
                max_qty = UINT_MAX / card->erase_size;
                min_qty = card->pref_erase / card->erase_size;
        }

        /*
         * We should not only use 'host->max_busy_timeout' as the limitation
         * when deciding the max discard sectors. We should set a balance value
         * to improve the erase speed, and it can not get too long timeout at
         * the same time.
         *
         * Here we set 'card->pref_erase' as the minimal discard sectors no
         * matter what size of 'host->max_busy_timeout', but if the
         * 'host->max_busy_timeout' is large enough for more discard sectors,
         * then we can continue to increase the max discard sectors until we
         * get a balance value. In cases when the 'host->max_busy_timeout'
         * isn't specified, use the default max erase 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 (qty + x > min_qty && timeout > max_busy_timeout)
                                break;

                        if (timeout < last_timeout)
                                break;
                        last_timeout = timeout;
                        y = x;
                }
                qty += y;
        } while (y);

        if (!qty)
                return 0;

        /*
         * When specifying a sector range to trim, chances are we might cross
         * an erase-group boundary even if the amount of sectors is less than
         * one erase-group.
         * If we can only fit one erase-group in the controller timeout budget,
         * we have to care that erase-group boundaries are not crossed by a
         * single trim operation. We flag that special case with "eg_boundary".
         * In all other cases we can just decrement qty and pretend that we
         * always touch (qty + 1) erase-groups as a simple optimization.
         */
        if (qty == 1)
                card->eg_boundary = 1;
        else
                qty--;

        /* Convert qty to sectors */
        if (card->erase_shift)
                max_discard = qty << card->erase_shift;
        else if (mmc_card_sd(card))
                max_discard = qty + 1;
        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;

        /*
         * 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_card_can_trim(card)) {
                max_trim = mmc_do_calc_max_discard(card, MMC_TRIM_ARG);
                if (max_trim < max_discard || max_discard == 0)
                        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_busy_timeout ?
                host->max_busy_timeout : MMC_ERASE_TIMEOUT_MS);
        return max_discard;
}
EXPORT_SYMBOL(mmc_calc_max_discard);

bool mmc_card_is_blockaddr(struct mmc_card *card)
{
        return card ? mmc_card_blockaddr(card) : false;
}
EXPORT_SYMBOL(mmc_card_is_blockaddr);

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

        if (mmc_card_blockaddr(card) || mmc_card_ddr52(card) ||
            mmc_card_hs400(card) || mmc_card_hs400es(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)
{
        mmc_pwrseq_reset(host);

        if (!(host->caps & MMC_CAP_HW_RESET) || !host->ops->card_hw_reset)
                return;
        host->ops->card_hw_reset(host);
}

/**
 * mmc_hw_reset - reset the card in hardware
 * @card: card to be reset
 *
 * Hard reset the card. This function is only for upper layers, like the
 * block layer or card drivers. You cannot use it in host drivers (struct
 * mmc_card might be gone then).
 *
 * Return: 0 on success, -errno on failure
 */
int mmc_hw_reset(struct mmc_card *card)
{
        struct mmc_host *host = card->host;
        int ret;

        ret = host->bus_ops->hw_reset(host);
        if (ret < 0)
                pr_warn("%s: tried to HW reset card, got error %d\n",
                        mmc_hostname(host), ret);

        return ret;
}
EXPORT_SYMBOL(mmc_hw_reset);

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

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

        ret = host->bus_ops->sw_reset(host);
        if (ret)
                pr_warn("%s: tried to SW reset card, got error %d\n",
                        mmc_hostname(host), ret);

        return ret;
}
EXPORT_SYMBOL(mmc_sw_reset);

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

        pr_debug("%s: %s: trying to init card at %u Hz\n",
                mmc_hostname(host), __func__, host->f_init);

        mmc_power_up(host, host->ocr_avail);

        /*
         * 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.
         * Skip it if we already know that we do not support SDIO commands
         */
        if (!(host->caps2 & MMC_CAP2_NO_SDIO))
                sdio_reset(host);

        mmc_go_idle(host);

        if (!(host->caps2 & MMC_CAP2_NO_SD)) {
                if (mmc_send_if_cond_pcie(host, host->ocr_avail))
                        goto out;
                if (mmc_card_sd_express(host))
                        return 0;
        }

        /* Order's important: probe SDIO, then SD, then MMC */
        if (!(host->caps2 & MMC_CAP2_NO_SDIO))
                if (!mmc_attach_sdio(host))
                        return 0;

        if (!(host->caps2 & MMC_CAP2_NO_SD))
                if (!mmc_attach_sd(host))
                        return 0;

        if (!(host->caps2 & MMC_CAP2_NO_MMC))
                if (!mmc_attach_mmc(host))
                        return 0;

out:
        mmc_power_off(host);
        return -EIO;
}

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

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

        ret = host->bus_ops->alive(host);

        /*
         * Card detect status and alive check may be out of sync if card is
         * removed slowly, when card detect switch changes while card/slot
         * pads are still contacted in hardware (refer to "SD Card Mechanical
         * Addendum, Appendix C: Card Detection Switch"). So reschedule a
         * detect work 200ms later for this case.
         */
        if (!ret && host->ops->get_cd && !host->ops->get_cd(host)) {
                mmc_detect_change(host, msecs_to_jiffies(200));
                pr_debug("%s: card removed too slowly\n", mmc_hostname(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;

        if (!mmc_card_is_removable(host))
                return 0;

        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))
                return ret;

        host->detect_change = 0;
        if (!ret) {
                ret = _mmc_detect_card_removed(host);
                if (ret && (host->caps & MMC_CAP_NEEDS_POLL)) {
                        /*
                         * 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, false);
                }
        }

        return ret;
}
EXPORT_SYMBOL(mmc_detect_card_removed);

int mmc_card_alternative_gpt_sector(struct mmc_card *card, sector_t *gpt_sector)
{
        unsigned int boot_sectors_num;

        if ((!(card->host->caps2 & MMC_CAP2_ALT_GPT_TEGRA)))
                return -EOPNOTSUPP;

        /* filter out unrelated cards */
        if (card->ext_csd.rev < 3 ||
            !mmc_card_mmc(card) ||
            !mmc_card_is_blockaddr(card) ||
             mmc_card_is_removable(card->host))
                return -ENOENT;

        /*
         * eMMC storage has two special boot partitions in addition to the
         * main one.  NVIDIA's bootloader linearizes eMMC boot0->boot1->main
         * accesses, this means that the partition table addresses are shifted
         * by the size of boot partitions.  In accordance with the eMMC
         * specification, the boot partition size is calculated as follows:
         *
         *      boot partition size = 128K byte x BOOT_SIZE_MULT
         *
         * Calculate number of sectors occupied by the both boot partitions.
         */
        boot_sectors_num = card->ext_csd.raw_boot_mult * SZ_128K /
                           SZ_512 * MMC_NUM_BOOT_PARTITION;

        /* Defined by NVIDIA and used by Android devices. */
        *gpt_sector = card->ext_csd.sectors - boot_sectors_num - 1;

        return 0;
}
EXPORT_SYMBOL(mmc_card_alternative_gpt_sector);

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 (!mmc_card_is_removable(host) && host->rescan_entered)
                return;
        host->rescan_entered = 1;

        if (host->trigger_card_event && host->ops->card_event) {
                mmc_claim_host(host);
                host->ops->card_event(host);
                mmc_release_host(host);
                host->trigger_card_event = false;
        }

        /* Verify a registered card to be functional, else remove it. */
        if (host->bus_ops)
                host->bus_ops->detect(host);

        host->detect_change = 0;

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

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

        /* If an SD express card is present, then leave it as is. */
        if (mmc_card_sd_express(host)) {
                mmc_release_host(host);
                goto out;
        }

        /*
         * Ideally we should favor initialization of legacy SD cards and defer
         * UHS-II enumeration. However, it seems like cards doesn't reliably
         * announce their support for UHS-II in the response to the ACMD41,
         * while initializing the legacy SD interface. Therefore, let's start
         * with UHS-II for now.
         */
        if (!mmc_attach_sd_uhs2(host)) {
                mmc_release_host(host);
                goto out;
        }

        for (i = 0; i < ARRAY_SIZE(freqs); i++) {
                unsigned int freq = freqs[i];
                if (freq > host->f_max) {
                        if (i + 1 < ARRAY_SIZE(freqs))
                                continue;
                        freq = host->f_max;
                }
                if (!mmc_rescan_try_freq(host, max(freq, host->f_min)))
                        break;
                if (freqs[i] <= host->f_min)
                        break;
        }

        /* A non-removable card should have been detected by now. */
        if (!mmc_card_is_removable(host) && !host->bus_ops)
                pr_info("%s: Failed to initialize a non-removable card",
                        mmc_hostname(host));

        /*
         * Ignore the command timeout errors observed during
         * the card init as those are excepted.
         */
        host->err_stats[MMC_ERR_CMD_TIMEOUT] = 0;
        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)
{
        bool power_up = !(host->caps2 &
                         (MMC_CAP2_NO_PRESCAN_POWERUP | MMC_CAP2_SD_UHS2));

        host->f_init = max(min(freqs[0], host->f_max), host->f_min);
        host->rescan_disable = 0;

        if (power_up) {
                mmc_claim_host(host);
                mmc_power_up(host, host->ocr_avail);
                mmc_release_host(host);
        }

        mmc_gpiod_request_cd_irq(host);
        _mmc_detect_change(host, 0, false);
}

void __mmc_stop_host(struct mmc_host *host)
{
        if (host->rescan_disable)
                return;

        if (host->slot.cd_irq >= 0) {
                mmc_gpio_set_cd_wake(host, false);
                disable_irq(host->slot.cd_irq);
        }

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

void mmc_stop_host(struct mmc_host *host)
{
        __mmc_stop_host(host);

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

        if (host->bus_ops) {
                /* Calling bus_ops->remove() with a claimed host can deadlock */
                host->bus_ops->remove(host);
                mmc_claim_host(host);
                mmc_detach_bus(host);
                mmc_power_off(host);
                mmc_release_host(host);
                return;
        }

        mmc_claim_host(host);
        mmc_power_off(host);
        mmc_release_host(host);
}

static int __init mmc_init(void)
{
        int ret;

        ret = mmc_register_bus();
        if (ret)
                return ret;

        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();
        return ret;
}

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

subsys_initcall(mmc_init);
module_exit(mmc_exit);

MODULE_DESCRIPTION("MMC core driver");
MODULE_LICENSE("GPL");