/*
 *  linux/drivers/mmc/core/sd.c
 *
 *  Copyright (C) 2003-2004 Russell King, All Rights Reserved.
 *  SD support Copyright (C) 2004 Ian Molton, All Rights Reserved.
 *  Copyright (C) 2005-2007 Pierre Ossman, 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/err.h>
#include <linux/sizes.h>
#include <linux/slab.h>
#include <linux/stat.h>
#include <linux/pm_runtime.h>

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

#include "core.h"
#include "card.h"
#include "host.h"
#include "bus.h"
#include "mmc_ops.h"
#include "sd.h"
#include "sd_ops.h"

static const unsigned int tran_exp[] = {
        10000,          100000,         1000000,        10000000,
        0,              0,              0,              0
};

static const unsigned char tran_mant[] = {
        0,      10,     12,     13,     15,     20,     25,     30,
        35,     40,     45,     50,     55,     60,     70,     80,
};

static const unsigned int taac_exp[] = {
        1,      10,     100,    1000,   10000,  100000, 1000000, 10000000,
};

static const unsigned int taac_mant[] = {
        0,      10,     12,     13,     15,     20,     25,     30,
        35,     40,     45,     50,     55,     60,     70,     80,
};

static const unsigned int sd_au_size[] = {
        0,              SZ_16K / 512,           SZ_32K / 512,   SZ_64K / 512,
        SZ_128K / 512,  SZ_256K / 512,          SZ_512K / 512,  SZ_1M / 512,
        SZ_2M / 512,    SZ_4M / 512,            SZ_8M / 512,    (SZ_8M + SZ_4M) / 512,
        SZ_16M / 512,   (SZ_16M + SZ_8M) / 512, SZ_32M / 512,   SZ_64M / 512,
};

#define UNSTUFF_BITS(resp,start,size)                                   \
        ({                                                              \
                const int __size = size;                                \
                const u32 __mask = (__size < 32 ? 1 << __size : 0) - 1; \
                const int __off = 3 - ((start) / 32);                   \
                const int __shft = (start) & 31;                        \
                u32 __res;                                              \
                                                                        \
                __res = resp[__off] >> __shft;                          \
                if (__size + __shft > 32)                               \
                        __res |= resp[__off-1] << ((32 - __shft) % 32); \
                __res & __mask;                                         \
        })

/*
 * Given the decoded CSD structure, decode the raw CID to our CID structure.
 */
void mmc_decode_cid(struct mmc_card *card)
{
        u32 *resp = card->raw_cid;

        /*
         * SD doesn't currently have a version field so we will
         * have to assume we can parse this.
         */
        card->cid.manfid                = UNSTUFF_BITS(resp, 120, 8);
        card->cid.oemid                 = UNSTUFF_BITS(resp, 104, 16);
        card->cid.prod_name[0]          = UNSTUFF_BITS(resp, 96, 8);
        card->cid.prod_name[1]          = UNSTUFF_BITS(resp, 88, 8);
        card->cid.prod_name[2]          = UNSTUFF_BITS(resp, 80, 8);
        card->cid.prod_name[3]          = UNSTUFF_BITS(resp, 72, 8);
        card->cid.prod_name[4]          = UNSTUFF_BITS(resp, 64, 8);
        card->cid.hwrev                 = UNSTUFF_BITS(resp, 60, 4);
        card->cid.fwrev                 = UNSTUFF_BITS(resp, 56, 4);
        card->cid.serial                = UNSTUFF_BITS(resp, 24, 32);
        card->cid.year                  = UNSTUFF_BITS(resp, 12, 8);
        card->cid.month                 = UNSTUFF_BITS(resp, 8, 4);

        card->cid.year += 2000; /* SD cards year offset */
}

/*
 * Given a 128-bit response, decode to our card CSD structure.
 */
static int mmc_decode_csd(struct mmc_card *card)
{
        struct mmc_csd *csd = &card->csd;
        unsigned int e, m, csd_struct;
        u32 *resp = card->raw_csd;

        csd_struct = UNSTUFF_BITS(resp, 126, 2);

        switch (csd_struct) {
        case 0:
                m = UNSTUFF_BITS(resp, 115, 4);
                e = UNSTUFF_BITS(resp, 112, 3);
                csd->taac_ns     = (taac_exp[e] * taac_mant[m] + 9) / 10;
                csd->taac_clks   = UNSTUFF_BITS(resp, 104, 8) * 100;

                m = UNSTUFF_BITS(resp, 99, 4);
                e = UNSTUFF_BITS(resp, 96, 3);
                csd->max_dtr      = tran_exp[e] * tran_mant[m];
                csd->cmdclass     = UNSTUFF_BITS(resp, 84, 12);

                e = UNSTUFF_BITS(resp, 47, 3);
                m = UNSTUFF_BITS(resp, 62, 12);
                csd->capacity     = (1 + m) << (e + 2);

                csd->read_blkbits = UNSTUFF_BITS(resp, 80, 4);
                csd->read_partial = UNSTUFF_BITS(resp, 79, 1);
                csd->write_misalign = UNSTUFF_BITS(resp, 78, 1);
                csd->read_misalign = UNSTUFF_BITS(resp, 77, 1);
                csd->dsr_imp = UNSTUFF_BITS(resp, 76, 1);
                csd->r2w_factor = UNSTUFF_BITS(resp, 26, 3);
                csd->write_blkbits = UNSTUFF_BITS(resp, 22, 4);
                csd->write_partial = UNSTUFF_BITS(resp, 21, 1);

                if (UNSTUFF_BITS(resp, 46, 1)) {
                        csd->erase_size = 1;
                } else if (csd->write_blkbits >= 9) {
                        csd->erase_size = UNSTUFF_BITS(resp, 39, 7) + 1;
                        csd->erase_size <<= csd->write_blkbits - 9;
                }
                break;
        case 1:
                /*
                 * This is a block-addressed SDHC or SDXC card. Most
                 * interesting fields are unused and have fixed
                 * values. To avoid getting tripped by buggy cards,
                 * we assume those fixed values ourselves.
                 */
                mmc_card_set_blockaddr(card);

                csd->taac_ns     = 0; /* Unused */
                csd->taac_clks   = 0; /* Unused */

                m = UNSTUFF_BITS(resp, 99, 4);
                e = UNSTUFF_BITS(resp, 96, 3);
                csd->max_dtr      = tran_exp[e] * tran_mant[m];
                csd->cmdclass     = UNSTUFF_BITS(resp, 84, 12);
                csd->c_size       = UNSTUFF_BITS(resp, 48, 22);

                /* SDXC cards have a minimum C_SIZE of 0x00FFFF */
                if (csd->c_size >= 0xFFFF)
                        mmc_card_set_ext_capacity(card);

                m = UNSTUFF_BITS(resp, 48, 22);
                csd->capacity     = (1 + m) << 10;

                csd->read_blkbits = 9;
                csd->read_partial = 0;
                csd->write_misalign = 0;
                csd->read_misalign = 0;
                csd->r2w_factor = 4; /* Unused */
                csd->write_blkbits = 9;
                csd->write_partial = 0;
                csd->erase_size = 1;
                break;
        default:
                pr_err("%s: unrecognised CSD structure version %d\n",
                        mmc_hostname(card->host), csd_struct);
                return -EINVAL;
        }

        card->erase_size = csd->erase_size;

        return 0;
}

/*
 * Given a 64-bit response, decode to our card SCR structure.
 */
static int mmc_decode_scr(struct mmc_card *card)
{
        struct sd_scr *scr = &card->scr;
        unsigned int scr_struct;
        u32 resp[4];

        resp[3] = card->raw_scr[1];
        resp[2] = card->raw_scr[0];

        scr_struct = UNSTUFF_BITS(resp, 60, 4);
        if (scr_struct != 0) {
                pr_err("%s: unrecognised SCR structure version %d\n",
                        mmc_hostname(card->host), scr_struct);
                return -EINVAL;
        }

        scr->sda_vsn = UNSTUFF_BITS(resp, 56, 4);
        scr->bus_widths = UNSTUFF_BITS(resp, 48, 4);
        if (scr->sda_vsn == SCR_SPEC_VER_2)
                /* Check if Physical Layer Spec v3.0 is supported */
                scr->sda_spec3 = UNSTUFF_BITS(resp, 47, 1);

        if (UNSTUFF_BITS(resp, 55, 1))
                card->erased_byte = 0xFF;
        else
                card->erased_byte = 0x0;

        if (scr->sda_spec3)
                scr->cmds = UNSTUFF_BITS(resp, 32, 2);
        return 0;
}

/*
 * Fetch and process SD Status register.
 */
static int mmc_read_ssr(struct mmc_card *card)
{
        unsigned int au, es, et, eo;
        __be32 *raw_ssr;
        int i;

        if (!(card->csd.cmdclass & CCC_APP_SPEC)) {
                pr_warn("%s: card lacks mandatory SD Status function\n",
                        mmc_hostname(card->host));
                return 0;
        }

        raw_ssr = kmalloc(sizeof(card->raw_ssr), GFP_KERNEL);
        if (!raw_ssr)
                return -ENOMEM;

        if (mmc_app_sd_status(card, raw_ssr)) {
                pr_warn("%s: problem reading SD Status register\n",
                        mmc_hostname(card->host));
                kfree(raw_ssr);
                return 0;
        }

        for (i = 0; i < 16; i++)
                card->raw_ssr[i] = be32_to_cpu(raw_ssr[i]);

        kfree(raw_ssr);

        /*
         * UNSTUFF_BITS only works with four u32s so we have to offset the
         * bitfield positions accordingly.
         */
        au = UNSTUFF_BITS(card->raw_ssr, 428 - 384, 4);
        if (au) {
                if (au <= 9 || card->scr.sda_spec3) {
                        card->ssr.au = sd_au_size[au];
                        es = UNSTUFF_BITS(card->raw_ssr, 408 - 384, 16);
                        et = UNSTUFF_BITS(card->raw_ssr, 402 - 384, 6);
                        if (es && et) {
                                eo = UNSTUFF_BITS(card->raw_ssr, 400 - 384, 2);
                                card->ssr.erase_timeout = (et * 1000) / es;
                                card->ssr.erase_offset = eo * 1000;
                        }
                } else {
                        pr_warn("%s: SD Status: Invalid Allocation Unit size\n",
                                mmc_hostname(card->host));
                }
        }

        return 0;
}

/*
 * Fetches and decodes switch information
 */
static int mmc_read_switch(struct mmc_card *card)
{
        int err;
        u8 *status;

        if (card->scr.sda_vsn < SCR_SPEC_VER_1)
                return 0;

        if (!(card->csd.cmdclass & CCC_SWITCH)) {
                pr_warn("%s: card lacks mandatory switch function, performance might suffer\n",
                        mmc_hostname(card->host));
                return 0;
        }

        status = kmalloc(64, GFP_KERNEL);
        if (!status)
                return -ENOMEM;

        /*
         * Find out the card's support bits with a mode 0 operation.
         * The argument does not matter, as the support bits do not
         * change with the arguments.
         */
        err = mmc_sd_switch(card, 0, 0, 0, status);
        if (err) {
                /*
                 * If the host or the card can't do the switch,
                 * fail more gracefully.
                 */
                if (err != -EINVAL && err != -ENOSYS && err != -EFAULT)
                        goto out;

                pr_warn("%s: problem reading Bus Speed modes\n",
                        mmc_hostname(card->host));
                err = 0;

                goto out;
        }

        if (status[13] & SD_MODE_HIGH_SPEED)
                card->sw_caps.hs_max_dtr = HIGH_SPEED_MAX_DTR;

        if (card->scr.sda_spec3) {
                card->sw_caps.sd3_bus_mode = status[13];
                /* Driver Strengths supported by the card */
                card->sw_caps.sd3_drv_type = status[9];
                card->sw_caps.sd3_curr_limit = status[7] | status[6] << 8;
        }

out:
        kfree(status);

        return err;
}

/*
 * Test if the card supports high-speed mode and, if so, switch to it.
 */
int mmc_sd_switch_hs(struct mmc_card *card)
{
        int err;
        u8 *status;

        if (card->scr.sda_vsn < SCR_SPEC_VER_1)
                return 0;

        if (!(card->csd.cmdclass & CCC_SWITCH))
                return 0;

        if (!(card->host->caps & MMC_CAP_SD_HIGHSPEED))
                return 0;

        if (card->sw_caps.hs_max_dtr == 0)
                return 0;

        status = kmalloc(64, GFP_KERNEL);
        if (!status)
                return -ENOMEM;

        err = mmc_sd_switch(card, 1, 0, 1, status);
        if (err)
                goto out;

        if ((status[16] & 0xF) != 1) {
                pr_warn("%s: Problem switching card into high-speed mode!\n",
                        mmc_hostname(card->host));
                err = 0;
        } else {
                err = 1;
        }

out:
        kfree(status);

        return err;
}

static int sd_select_driver_type(struct mmc_card *card, u8 *status)
{
        int card_drv_type, drive_strength, drv_type;
        int err;

        card->drive_strength = 0;

        card_drv_type = card->sw_caps.sd3_drv_type | SD_DRIVER_TYPE_B;

        drive_strength = mmc_select_drive_strength(card,
                                                   card->sw_caps.uhs_max_dtr,
                                                   card_drv_type, &drv_type);

        if (drive_strength) {
                err = mmc_sd_switch(card, 1, 2, drive_strength, status);
                if (err)
                        return err;
                if ((status[15] & 0xF) != drive_strength) {
                        pr_warn("%s: Problem setting drive strength!\n",
                                mmc_hostname(card->host));
                        return 0;
                }
                card->drive_strength = drive_strength;
        }

        if (drv_type)
                mmc_set_driver_type(card->host, drv_type);

        return 0;
}

static void sd_update_bus_speed_mode(struct mmc_card *card)
{
        /*
         * If the host doesn't support any of the UHS-I modes, fallback on
         * default speed.
         */
        if (!mmc_host_uhs(card->host)) {
                card->sd_bus_speed = 0;
                return;
        }

        if ((card->host->caps & MMC_CAP_UHS_SDR104) &&
            (card->sw_caps.sd3_bus_mode & SD_MODE_UHS_SDR104)) {
                        card->sd_bus_speed = UHS_SDR104_BUS_SPEED;
        } else if ((card->host->caps & MMC_CAP_UHS_DDR50) &&
                   (card->sw_caps.sd3_bus_mode & SD_MODE_UHS_DDR50)) {
                        card->sd_bus_speed = UHS_DDR50_BUS_SPEED;
        } else if ((card->host->caps & (MMC_CAP_UHS_SDR104 |
                    MMC_CAP_UHS_SDR50)) && (card->sw_caps.sd3_bus_mode &
                    SD_MODE_UHS_SDR50)) {
                        card->sd_bus_speed = UHS_SDR50_BUS_SPEED;
        } else if ((card->host->caps & (MMC_CAP_UHS_SDR104 |
                    MMC_CAP_UHS_SDR50 | MMC_CAP_UHS_SDR25)) &&
                   (card->sw_caps.sd3_bus_mode & SD_MODE_UHS_SDR25)) {
                        card->sd_bus_speed = UHS_SDR25_BUS_SPEED;
        } else if ((card->host->caps & (MMC_CAP_UHS_SDR104 |
                    MMC_CAP_UHS_SDR50 | MMC_CAP_UHS_SDR25 |
                    MMC_CAP_UHS_SDR12)) && (card->sw_caps.sd3_bus_mode &
                    SD_MODE_UHS_SDR12)) {
                        card->sd_bus_speed = UHS_SDR12_BUS_SPEED;
        }
}

static int sd_set_bus_speed_mode(struct mmc_card *card, u8 *status)
{
        int err;
        unsigned int timing = 0;

        switch (card->sd_bus_speed) {
        case UHS_SDR104_BUS_SPEED:
                timing = MMC_TIMING_UHS_SDR104;
                card->sw_caps.uhs_max_dtr = UHS_SDR104_MAX_DTR;
                break;
        case UHS_DDR50_BUS_SPEED:
                timing = MMC_TIMING_UHS_DDR50;
                card->sw_caps.uhs_max_dtr = UHS_DDR50_MAX_DTR;
                break;
        case UHS_SDR50_BUS_SPEED:
                timing = MMC_TIMING_UHS_SDR50;
                card->sw_caps.uhs_max_dtr = UHS_SDR50_MAX_DTR;
                break;
        case UHS_SDR25_BUS_SPEED:
                timing = MMC_TIMING_UHS_SDR25;
                card->sw_caps.uhs_max_dtr = UHS_SDR25_MAX_DTR;
                break;
        case UHS_SDR12_BUS_SPEED:
                timing = MMC_TIMING_UHS_SDR12;
                card->sw_caps.uhs_max_dtr = UHS_SDR12_MAX_DTR;
                break;
        default:
                return 0;
        }

        err = mmc_sd_switch(card, 1, 0, card->sd_bus_speed, status);
        if (err)
                return err;

        if ((status[16] & 0xF) != card->sd_bus_speed)
                pr_warn("%s: Problem setting bus speed mode!\n",
                        mmc_hostname(card->host));
        else {
                mmc_set_timing(card->host, timing);
                mmc_set_clock(card->host, card->sw_caps.uhs_max_dtr);
        }

        return 0;
}

/* Get host's max current setting at its current voltage */
static u32 sd_get_host_max_current(struct mmc_host *host)
{
        u32 voltage, max_current;

        voltage = 1 << host->ios.vdd;
        switch (voltage) {
        case MMC_VDD_165_195:
                max_current = host->max_current_180;
                break;
        case MMC_VDD_29_30:
        case MMC_VDD_30_31:
                max_current = host->max_current_300;
                break;
        case MMC_VDD_32_33:
        case MMC_VDD_33_34:
                max_current = host->max_current_330;
                break;
        default:
                max_current = 0;
        }

        return max_current;
}

static int sd_set_current_limit(struct mmc_card *card, u8 *status)
{
        int current_limit = SD_SET_CURRENT_NO_CHANGE;
        int err;
        u32 max_current;

        /*
         * Current limit switch is only defined for SDR50, SDR104, and DDR50
         * bus speed modes. For other bus speed modes, we do not change the
         * current limit.
         */
        if ((card->sd_bus_speed != UHS_SDR50_BUS_SPEED) &&
            (card->sd_bus_speed != UHS_SDR104_BUS_SPEED) &&
            (card->sd_bus_speed != UHS_DDR50_BUS_SPEED))
                return 0;

        /*
         * Host has different current capabilities when operating at
         * different voltages, so find out its max current first.
         */
        max_current = sd_get_host_max_current(card->host);

        /*
         * We only check host's capability here, if we set a limit that is
         * higher than the card's maximum current, the card will be using its
         * maximum current, e.g. if the card's maximum current is 300ma, and
         * when we set current limit to 200ma, the card will draw 200ma, and
         * when we set current limit to 400/600/800ma, the card will draw its
         * maximum 300ma from the host.
         *
         * The above is incorrect: if we try to set a current limit that is
         * not supported by the card, the card can rightfully error out the
         * attempt, and remain at the default current limit.  This results
         * in a 300mA card being limited to 200mA even though the host
         * supports 800mA. Failures seen with SanDisk 8GB UHS cards with
         * an iMX6 host. --rmk
         */
        if (max_current >= 800 &&
            card->sw_caps.sd3_curr_limit & SD_MAX_CURRENT_800)
                current_limit = SD_SET_CURRENT_LIMIT_800;
        else if (max_current >= 600 &&
                 card->sw_caps.sd3_curr_limit & SD_MAX_CURRENT_600)
                current_limit = SD_SET_CURRENT_LIMIT_600;
        else if (max_current >= 400 &&
                 card->sw_caps.sd3_curr_limit & SD_MAX_CURRENT_400)
                current_limit = SD_SET_CURRENT_LIMIT_400;
        else if (max_current >= 200 &&
                 card->sw_caps.sd3_curr_limit & SD_MAX_CURRENT_200)
                current_limit = SD_SET_CURRENT_LIMIT_200;

        if (current_limit != SD_SET_CURRENT_NO_CHANGE) {
                err = mmc_sd_switch(card, 1, 3, current_limit, status);
                if (err)
                        return err;

                if (((status[15] >> 4) & 0x0F) != current_limit)
                        pr_warn("%s: Problem setting current limit!\n",
                                mmc_hostname(card->host));

        }

        return 0;
}

/*
 * UHS-I specific initialization procedure
 */
static int mmc_sd_init_uhs_card(struct mmc_card *card)
{
        int err;
        u8 *status;

        if (!(card->csd.cmdclass & CCC_SWITCH))
                return 0;

        status = kmalloc(64, GFP_KERNEL);
        if (!status)
                return -ENOMEM;

        /* Set 4-bit bus width */
        err = mmc_app_set_bus_width(card, MMC_BUS_WIDTH_4);
        if (err)
                goto out;

        mmc_set_bus_width(card->host, MMC_BUS_WIDTH_4);

        /*
         * Select the bus speed mode depending on host
         * and card capability.
         */
        sd_update_bus_speed_mode(card);

        /* Set the driver strength for the card */
        err = sd_select_driver_type(card, status);
        if (err)
                goto out;

        /* Set current limit for the card */
        err = sd_set_current_limit(card, status);
        if (err)
                goto out;

        /* Set bus speed mode of the card */
        err = sd_set_bus_speed_mode(card, status);
        if (err)
                goto out;

        /*
         * SPI mode doesn't define CMD19 and tuning is only valid for SDR50 and
         * SDR104 mode SD-cards. Note that tuning is mandatory for SDR104.
         */
        if (!mmc_host_is_spi(card->host) &&
                (card->host->ios.timing == MMC_TIMING_UHS_SDR50 ||
                 card->host->ios.timing == MMC_TIMING_UHS_DDR50 ||
                 card->host->ios.timing == MMC_TIMING_UHS_SDR104)) {
                err = mmc_execute_tuning(card);

                /*
                 * As SD Specifications Part1 Physical Layer Specification
                 * Version 3.01 says, CMD19 tuning is available for unlocked
                 * cards in transfer state of 1.8V signaling mode. The small
                 * difference between v3.00 and 3.01 spec means that CMD19
                 * tuning is also available for DDR50 mode.
                 */
                if (err && card->host->ios.timing == MMC_TIMING_UHS_DDR50) {
                        pr_warn("%s: ddr50 tuning failed\n",
                                mmc_hostname(card->host));
                        err = 0;
                }
        }

out:
        kfree(status);

        return err;
}

MMC_DEV_ATTR(cid, "%08x%08x%08x%08x\n", card->raw_cid[0], card->raw_cid[1],
        card->raw_cid[2], card->raw_cid[3]);
MMC_DEV_ATTR(csd, "%08x%08x%08x%08x\n", card->raw_csd[0], card->raw_csd[1],
        card->raw_csd[2], card->raw_csd[3]);
MMC_DEV_ATTR(scr, "%08x%08x\n", card->raw_scr[0], card->raw_scr[1]);
MMC_DEV_ATTR(ssr,
        "%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x\n",
                card->raw_ssr[0], card->raw_ssr[1], card->raw_ssr[2],
                card->raw_ssr[3], card->raw_ssr[4], card->raw_ssr[5],
                card->raw_ssr[6], card->raw_ssr[7], card->raw_ssr[8],
                card->raw_ssr[9], card->raw_ssr[10], card->raw_ssr[11],
                card->raw_ssr[12], card->raw_ssr[13], card->raw_ssr[14],
                card->raw_ssr[15]);
MMC_DEV_ATTR(date, "%02d/%04d\n", card->cid.month, card->cid.year);
MMC_DEV_ATTR(erase_size, "%u\n", card->erase_size << 9);
MMC_DEV_ATTR(preferred_erase_size, "%u\n", card->pref_erase << 9);
MMC_DEV_ATTR(fwrev, "0x%x\n", card->cid.fwrev);
MMC_DEV_ATTR(hwrev, "0x%x\n", card->cid.hwrev);
MMC_DEV_ATTR(manfid, "0x%06x\n", card->cid.manfid);
MMC_DEV_ATTR(name, "%s\n", card->cid.prod_name);
MMC_DEV_ATTR(oemid, "0x%04x\n", card->cid.oemid);
MMC_DEV_ATTR(serial, "0x%08x\n", card->cid.serial);
MMC_DEV_ATTR(ocr, "0x%08x\n", card->ocr);
MMC_DEV_ATTR(rca, "0x%04x\n", card->rca);


static ssize_t mmc_dsr_show(struct device *dev,
                           struct device_attribute *attr,
                           char *buf)
{
       struct mmc_card *card = mmc_dev_to_card(dev);
       struct mmc_host *host = card->host;

       if (card->csd.dsr_imp && host->dsr_req)
               return sprintf(buf, "0x%x\n", host->dsr);
       else
               /* return default DSR value */
               return sprintf(buf, "0x%x\n", 0x404);
}

static DEVICE_ATTR(dsr, S_IRUGO, mmc_dsr_show, NULL);

static struct attribute *sd_std_attrs[] = {
        &dev_attr_cid.attr,
        &dev_attr_csd.attr,
        &dev_attr_scr.attr,
        &dev_attr_ssr.attr,
        &dev_attr_date.attr,
        &dev_attr_erase_size.attr,
        &dev_attr_preferred_erase_size.attr,
        &dev_attr_fwrev.attr,
        &dev_attr_hwrev.attr,
        &dev_attr_manfid.attr,
        &dev_attr_name.attr,
        &dev_attr_oemid.attr,
        &dev_attr_serial.attr,
        &dev_attr_ocr.attr,
        &dev_attr_rca.attr,
        &dev_attr_dsr.attr,
        NULL,
};
ATTRIBUTE_GROUPS(sd_std);

struct device_type sd_type = {
        .groups = sd_std_groups,
};

/*
 * Fetch CID from card.
 */
int mmc_sd_get_cid(struct mmc_host *host, u32 ocr, u32 *cid, u32 *rocr)
{
        int err;
        u32 max_current;
        int retries = 10;
        u32 pocr = ocr;

try_again:
        if (!retries) {
                ocr &= ~SD_OCR_S18R;
                pr_warn("%s: Skipping voltage switch\n", mmc_hostname(host));
        }

        /*
         * Since we're changing the OCR value, we seem to
         * need to tell some cards to go back to the idle
         * state.  We wait 1ms to give cards time to
         * respond.
         */
        mmc_go_idle(host);

        /*
         * If SD_SEND_IF_COND indicates an SD 2.0
         * compliant card and we should set bit 30
         * of the ocr to indicate that we can handle
         * block-addressed SDHC cards.
         */
        err = mmc_send_if_cond(host, ocr);
        if (!err)
                ocr |= SD_OCR_CCS;

        /*
         * If the host supports one of UHS-I modes, request the card
         * to switch to 1.8V signaling level. If the card has failed
         * repeatedly to switch however, skip this.
         */
        if (retries && mmc_host_uhs(host))
                ocr |= SD_OCR_S18R;

        /*
         * If the host can supply more than 150mA at current voltage,
         * XPC should be set to 1.
         */
        max_current = sd_get_host_max_current(host);
        if (max_current > 150)
                ocr |= SD_OCR_XPC;

        err = mmc_send_app_op_cond(host, ocr, rocr);
        if (err)
                return err;

        /*
         * In case CCS and S18A in the response is set, start Signal Voltage
         * Switch procedure. SPI mode doesn't support CMD11.
         */
        if (!mmc_host_is_spi(host) && rocr &&
           ((*rocr & 0x41000000) == 0x41000000)) {
                err = mmc_set_uhs_voltage(host, pocr);
                if (err == -EAGAIN) {
                        retries--;
                        goto try_again;
                } else if (err) {
                        retries = 0;
                        goto try_again;
                }
        }

        err = mmc_send_cid(host, cid);
        return err;
}

int mmc_sd_get_csd(struct mmc_host *host, struct mmc_card *card)
{
        int err;

        /*
         * Fetch CSD from card.
         */
        err = mmc_send_csd(card, card->raw_csd);
        if (err)
                return err;

        err = mmc_decode_csd(card);
        if (err)
                return err;

        return 0;
}

static int mmc_sd_get_ro(struct mmc_host *host)
{
        int ro;

        /*
         * Some systems don't feature a write-protect pin and don't need one.
         * E.g. because they only have micro-SD card slot. For those systems
         * assume that the SD card is always read-write.
         */
        if (host->caps2 & MMC_CAP2_NO_WRITE_PROTECT)
                return 0;

        if (!host->ops->get_ro)
                return -1;

        ro = host->ops->get_ro(host);

        return ro;
}

int mmc_sd_setup_card(struct mmc_host *host, struct mmc_card *card,
        bool reinit)
{
        int err;

        if (!reinit) {
                /*
                 * Fetch SCR from card.
                 */
                err = mmc_app_send_scr(card);
                if (err)
                        return err;

                err = mmc_decode_scr(card);
                if (err)
                        return err;

                /*
                 * Fetch and process SD Status register.
                 */
                err = mmc_read_ssr(card);
                if (err)
                        return err;

                /* Erase init depends on CSD and SSR */
                mmc_init_erase(card);

                /*
                 * Fetch switch information from card.
                 */
                err = mmc_read_switch(card);
                if (err)
                        return err;
        }

        /*
         * For SPI, enable CRC as appropriate.
         * This CRC enable is located AFTER the reading of the
         * card registers because some SDHC cards are not able
         * to provide valid CRCs for non-512-byte blocks.
         */
        if (mmc_host_is_spi(host)) {
                err = mmc_spi_set_crc(host, use_spi_crc);
                if (err)
                        return err;
        }

        /*
         * Check if read-only switch is active.
         */
        if (!reinit) {
                int ro = mmc_sd_get_ro(host);

                if (ro < 0) {
                        pr_warn("%s: host does not support reading read-only switch, assuming write-enable\n",
                                mmc_hostname(host));
                } else if (ro > 0) {
                        mmc_card_set_readonly(card);
                }
        }

        return 0;
}

unsigned mmc_sd_get_max_clock(struct mmc_card *card)
{
        unsigned max_dtr = (unsigned int)-1;

        if (mmc_card_hs(card)) {
                if (max_dtr > card->sw_caps.hs_max_dtr)
                        max_dtr = card->sw_caps.hs_max_dtr;
        } else if (max_dtr > card->csd.max_dtr) {
                max_dtr = card->csd.max_dtr;
        }

        return max_dtr;
}

static bool mmc_sd_card_using_v18(struct mmc_card *card)
{
        /*
         * According to the SD spec., the Bus Speed Mode (function group 1) bits
         * 2 to 4 are zero if the card is initialized at 3.3V signal level. Thus
         * they can be used to determine if the card has already switched to
         * 1.8V signaling.
         */
        return card->sw_caps.sd3_bus_mode &
               (SD_MODE_UHS_SDR50 | SD_MODE_UHS_SDR104 | SD_MODE_UHS_DDR50);
}

/*
 * Handle the detection and initialisation of a card.
 *
 * In the case of a resume, "oldcard" will contain the card
 * we're trying to reinitialise.
 */
static int mmc_sd_init_card(struct mmc_host *host, u32 ocr,
        struct mmc_card *oldcard)
{
        struct mmc_card *card;
        int err;
        u32 cid[4];
        u32 rocr = 0;
        bool v18_fixup_failed = false;

        WARN_ON(!host->claimed);
retry:
        err = mmc_sd_get_cid(host, ocr, cid, &rocr);
        if (err)
                return err;

        if (oldcard) {
                if (memcmp(cid, oldcard->raw_cid, sizeof(cid)) != 0)
                        return -ENOENT;

                card = oldcard;
        } else {
                /*
                 * Allocate card structure.
                 */
                card = mmc_alloc_card(host, &sd_type);
                if (IS_ERR(card))
                        return PTR_ERR(card);

                card->ocr = ocr;
                card->type = MMC_TYPE_SD;
                memcpy(card->raw_cid, cid, sizeof(card->raw_cid));
        }

        /*
         * Call the optional HC's init_card function to handle quirks.
         */
        if (host->ops->init_card)
                host->ops->init_card(host, card);

        /*
         * For native busses:  get card RCA and quit open drain mode.
         */
        if (!mmc_host_is_spi(host)) {
                err = mmc_send_relative_addr(host, &card->rca);
                if (err)
                        goto free_card;
        }

        if (!oldcard) {
                err = mmc_sd_get_csd(host, card);
                if (err)
                        goto free_card;

                mmc_decode_cid(card);
        }

        /*
         * handling only for cards supporting DSR and hosts requesting
         * DSR configuration
         */
        if (card->csd.dsr_imp && host->dsr_req)
                mmc_set_dsr(host);

        /*
         * Select card, as all following commands rely on that.
         */
        if (!mmc_host_is_spi(host)) {
                err = mmc_select_card(card);
                if (err)
                        goto free_card;
        }

        err = mmc_sd_setup_card(host, card, oldcard != NULL);
        if (err)
                goto free_card;

        /*
         * If the card has not been power cycled, it may still be using 1.8V

         * signaling. Detect that situation and try to initialize a UHS-I (1.8V)
         * transfer mode.
         */
        if (!v18_fixup_failed && !mmc_host_is_spi(host) && mmc_host_uhs(host) &&
            mmc_sd_card_using_v18(card) &&
            host->ios.signal_voltage != MMC_SIGNAL_VOLTAGE_180) {
                /*
                 * Re-read switch information in case it has changed since
                 * oldcard was initialized.
                 */
                if (oldcard) {
                        err = mmc_read_switch(card);
                        if (err)
                                goto free_card;
                }
                if (mmc_sd_card_using_v18(card)) {
                        if (mmc_host_set_uhs_voltage(host) ||
                            mmc_sd_init_uhs_card(card)) {
                                v18_fixup_failed = true;
                                mmc_power_cycle(host, ocr);
                                if (!oldcard)
                                        mmc_remove_card(card);
                                goto retry;
                        }
                        goto done;
                }
        }

        /* Initialization sequence for UHS-I cards */
        if (rocr & SD_ROCR_S18A && mmc_host_uhs(host)) {
                err = mmc_sd_init_uhs_card(card);
                if (err)
                        goto free_card;
        } else {
                /*
                 * Attempt to change to high-speed (if supported)
                 */
                err = mmc_sd_switch_hs(card);
                if (err > 0)
                        mmc_set_timing(card->host, MMC_TIMING_SD_HS);
                else if (err)
                        goto free_card;

                /*
                 * Set bus speed.
                 */
                mmc_set_clock(host, mmc_sd_get_max_clock(card));

                /*
                 * Switch to wider bus (if supported).
                 */
                if ((host->caps & MMC_CAP_4_BIT_DATA) &&
                        (card->scr.bus_widths & SD_SCR_BUS_WIDTH_4)) {
                        err = mmc_app_set_bus_width(card, MMC_BUS_WIDTH_4);
                        if (err)
                                goto free_card;

                        mmc_set_bus_width(host, MMC_BUS_WIDTH_4);
                }
        }
done:
        host->card = card;
        return 0;

free_card:
        if (!oldcard)
                mmc_remove_card(card);

        return err;
}

/*
 * Host is being removed. Free up the current card.
 */
static void mmc_sd_remove(struct mmc_host *host)
{
        mmc_remove_card(host->card);
        host->card = NULL;
}

/*
 * Card detection - card is alive.
 */
static int mmc_sd_alive(struct mmc_host *host)
{
        return mmc_send_status(host->card, NULL);
}

/*
 * Card detection callback from host.
 */
static void mmc_sd_detect(struct mmc_host *host)
{
        int err;

        mmc_get_card(host->card, NULL);

        /*
         * Just check if our card has been removed.
         */
        err = _mmc_detect_card_removed(host);

        mmc_put_card(host->card, NULL);

        if (err) {
                mmc_sd_remove(host);

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

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

        mmc_claim_host(host);

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

        if (!mmc_host_is_spi(host))
                err = mmc_deselect_cards(host);

        if (!err) {
                mmc_power_off(host);
                mmc_card_set_suspended(host->card);
        }

out:
        mmc_release_host(host);
        return err;
}

/*
 * Callback for suspend
 */
static int mmc_sd_suspend(struct mmc_host *host)
{
        int err;

        err = _mmc_sd_suspend(host);
        if (!err) {
                pm_runtime_disable(&host->card->dev);
                pm_runtime_set_suspended(&host->card->dev);
        }

        return err;
}

/*
 * This function tries to determine if the same card is still present
 * and, if so, restore all state to it.
 */
static int _mmc_sd_resume(struct mmc_host *host)
{
        int err = 0;

        mmc_claim_host(host);

        if (!mmc_card_suspended(host->card))
                goto out;

        mmc_power_up(host, host->card->ocr);
        err = mmc_sd_init_card(host, host->card->ocr, host->card);
        mmc_card_clr_suspended(host->card);

out:
        mmc_release_host(host);
        return err;
}

/*
 * Callback for resume
 */
static int mmc_sd_resume(struct mmc_host *host)
{
        pm_runtime_enable(&host->card->dev);
        return 0;
}

/*
 * Callback for runtime_suspend.
 */
static int mmc_sd_runtime_suspend(struct mmc_host *host)
{
        int err;

        if (!(host->caps & MMC_CAP_AGGRESSIVE_PM))
                return 0;

        err = _mmc_sd_suspend(host);
        if (err)
                pr_err("%s: error %d doing aggressive suspend\n",
                        mmc_hostname(host), err);

        return err;
}

/*
 * Callback for runtime_resume.
 */
static int mmc_sd_runtime_resume(struct mmc_host *host)
{
        int err;

        err = _mmc_sd_resume(host);
        if (err && err != -ENOMEDIUM)
                pr_err("%s: error %d doing runtime resume\n",
                        mmc_hostname(host), err);

        return 0;
}

static int mmc_sd_reset(struct mmc_host *host)
{
        mmc_power_cycle(host, host->card->ocr);
        return mmc_sd_init_card(host, host->card->ocr, host->card);
}

static const struct mmc_bus_ops mmc_sd_ops = {
        .remove = mmc_sd_remove,
        .detect = mmc_sd_detect,
        .runtime_suspend = mmc_sd_runtime_suspend,
        .runtime_resume = mmc_sd_runtime_resume,
        .suspend = mmc_sd_suspend,
        .resume = mmc_sd_resume,
        .alive = mmc_sd_alive,
        .shutdown = mmc_sd_suspend,
        .reset = mmc_sd_reset,
};

/*
 * Starting point for SD card init.
 */
int mmc_attach_sd(struct mmc_host *host)
{
        int err;
        u32 ocr, rocr;

        WARN_ON(!host->claimed);

        err = mmc_send_app_op_cond(host, 0, &ocr);
        if (err)
                return err;

        mmc_attach_bus(host, &mmc_sd_ops);
        if (host->ocr_avail_sd)
                host->ocr_avail = host->ocr_avail_sd;

        /*
         * We need to get OCR a different way for SPI.
         */
        if (mmc_host_is_spi(host)) {
                mmc_go_idle(host);

                err = mmc_spi_read_ocr(host, 0, &ocr);
                if (err)
                        goto err;
        }

        rocr = mmc_select_voltage(host, ocr);

        /*
         * Can we support the voltage(s) of the card(s)?
         */
        if (!rocr) {
                err = -EINVAL;
                goto err;
        }

        /*
         * Detect and init the card.
         */
        err = mmc_sd_init_card(host, rocr, NULL);
        if (err)
                goto err;

        mmc_release_host(host);
        err = mmc_add_card(host->card);
        if (err)
                goto remove_card;

        mmc_claim_host(host);
        return 0;

remove_card:
        mmc_remove_card(host->card);
        host->card = NULL;
        mmc_claim_host(host);
err:
        mmc_detach_bus(host);

        pr_err("%s: error %d whilst initialising SD card\n",
                mmc_hostname(host), err);

        return err;
}