kernel: vm kernel call can't suspend

[minix.git] / drivers / mmc / mmchost_mmchs.c

/* kernel headers */
#include <minix/blockdriver.h>
#include <minix/com.h>
#include <minix/vm.h>
#include <sys/mman.h>

/* usr headers */
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <inttypes.h>
#include <limits.h>

/* local headers */
#include "mmclog.h"
#include "mmchost.h"

/* header imported from netbsd */
#include "sdmmcreg.h"
#include "sdmmcreg.h"
#include "sdhcreg.h"

/* omap /hardware related */
#include "omap_mmc.h"

/*
 * Define a structure to be used for logging
 */
static struct mmclog log = {
        .name = "mmc_host_mmchs",
        .log_level = LEVEL_INFO,
        .log_func = default_log
};

#define REG(x)(*((volatile uint32_t *)(x)))
#define BIT(x)(0x1 << x)

/* Write a uint32_t value to a memory address. */
inline void
write32(uint32_t address, uint32_t value)
{
        REG(address) = value;
}

/* Read an uint32_t from a memory address */
inline uint32_t
read32(uint32_t address)
{

        return REG(address);
}

/* Set a 32 bits value depending on a mask */
inline void
set32(uint32_t address, uint32_t mask, uint32_t value)
{
        uint32_t val;
        val = read32(address);
        /* clear the bits */
        val &= ~(mask);
        /* apply the value using the mask */
        val |= (value & mask);
        write32(address, val);
}

static uint32_t base_address;

/*
 * Initialize the MMC controller given a certain
 * instance. this driver only handles a single
 * mmchs controller at a given time.
 */
int
mmchs_init(uint32_t instance)
{
        int counter;
        uint32_t value;

        counter = 0;
        value = 0;

        struct minix_mem_range mr;

        mr.mr_base = MMCHS1_REG_BASE;
        mr.mr_limit = MMCHS1_REG_BASE + 0x400;

        if (sys_privctl(SELF, SYS_PRIV_ADD_MEM, &mr) != 0) {
                panic("Unable to request permission to map memory");
        }

        /* Set the base address to use */
        base_address =
            (uint32_t) vm_map_phys(SELF, (void *) MMCHS1_REG_BASE, 0x400);
        if (base_address == (uint32_t) MAP_FAILED)
                panic("Unable to map MMC memory");

        base_address = (unsigned long) base_address - 0x100;

        /* Soft reset of the controller. This section is documented in the TRM 
         */

        /* Write 1 to sysconfig[0] to trigger a reset */
        set32(base_address + MMCHS_SD_SYSCONFIG, MMCHS_SD_SYSCONFIG_SOFTRESET,
            MMCHS_SD_SYSCONFIG_SOFTRESET);

        /* Read sysstatus to know when it's done */
        while (!(read32(base_address + MMCHS_SD_SYSSTATUS)
                & MMCHS_SD_SYSSTATUS_RESETDONE)) {
                /* TODO:Add proper delay and escape route */

                counter++;
        }

        /* Set SD default capabilities */
        set32(base_address + MMCHS_SD_CAPA, MMCHS_SD_CAPA_VS_MASK,
            MMCHS_SD_CAPA_VS18 | MMCHS_SD_CAPA_VS30);

        /* TRM mentions MMCHS_SD_CUR_CAPA but does not describe how to limit
         * the current */

        uint32_t mask =
            MMCHS_SD_SYSCONFIG_AUTOIDLE | MMCHS_SD_SYSCONFIG_ENAWAKEUP |
            MMCHS_SD_SYSCONFIG_STANDBYMODE | MMCHS_SD_SYSCONFIG_CLOCKACTIVITY |
            MMCHS_SD_SYSCONFIG_SIDLEMODE;

        /* Automatic clock gating strategy */
        value = MMCHS_SD_SYSCONFIG_AUTOIDLE_EN;
        /* Enable wake-up capability */
        value |= MMCHS_SD_SYSCONFIG_ENAWAKEUP_EN;
        /* Smart-idle */
        value |= MMCHS_SD_SYSCONFIG_SIDLEMODE_IDLE;
        /* Booth the interface and functional can be switched off */
        value |= MMCHS_SD_SYSCONFIG_CLOCKACTIVITY_OFF;
        /* Go into wake-up mode when possible */
        value |= MMCHS_SD_SYSCONFIG_STANDBYMODE_WAKEUP_INTERNAL;

        /* 
         * wake-up configuration
         */
        set32(base_address + MMCHS_SD_SYSCONFIG, mask, value);

        /* Wake-up on sd interrupt for SDIO */
        set32(base_address + MMCHS_SD_HCTL, MMCHS_SD_HCTL_IWE,
            MMCHS_SD_HCTL_IWE_EN);

        /* 
         * MMC host and bus configuration
         */

        /* Configure data and command transfer (1 bit mode) */
        set32(base_address + MMCHS_SD_CON, MMCHS_SD_CON_DW8,
            MMCHS_SD_CON_DW8_1BIT);
        set32(base_address + MMCHS_SD_HCTL, MMCHS_SD_HCTL_DTW,
            MMCHS_SD_HCTL_DTW_1BIT);

        /* Configure card voltage to 3.0 volt */
        set32(base_address + MMCHS_SD_HCTL, MMCHS_SD_HCTL_SDVS,
            MMCHS_SD_HCTL_SDVS_VS30);

        /* Power on the host controller and wait for the
         * MMCHS_SD_HCTL_SDBP_POWER_ON to be set */
        set32(base_address + MMCHS_SD_HCTL, MMCHS_SD_HCTL_SDBP,
            MMCHS_SD_HCTL_SDBP_ON);

        /* TODO: Add padconf stuff here as documented in the TRM */

        while ((read32(base_address + MMCHS_SD_HCTL) & MMCHS_SD_HCTL_SDBP)
            != MMCHS_SD_HCTL_SDBP_ON) {
                /* TODO:Add proper delay and escape route */
                counter++;
        }

        /* Enable internal clock and clock to the card */
        set32(base_address + MMCHS_SD_SYSCTL, MMCHS_SD_SYSCTL_ICE,
            MMCHS_SD_SYSCTL_ICE_EN);

        // @TODO Fix external clock enable , this one is very slow
        set32(base_address + MMCHS_SD_SYSCTL, MMCHS_SD_SYSCTL_CLKD,
            (0x3ff << 6));
        set32(base_address + MMCHS_SD_SYSCTL, MMCHS_SD_SYSCTL_CEN,
            MMCHS_SD_SYSCTL_CEN_EN);
        counter = 0;

        while ((read32(base_address + MMCHS_SD_SYSCTL) & MMCHS_SD_SYSCTL_ICS)
            != MMCHS_SD_SYSCTL_ICS_STABLE) {
                /* TODO:Add proper delay and escape route */
                counter++;
        }

        /* 
         * See spruh73e page 3576  Card Detection, Identification, and Selection
         */

        /* Enable command interrupt */
        set32(base_address + MMCHS_SD_IE, MMCHS_SD_IE_CC_ENABLE,
            MMCHS_SD_IE_CC_ENABLE_ENABLE);
        /* Enable transfer complete interrupt */
        set32(base_address + MMCHS_SD_IE, MMCHS_SD_IE_TC_ENABLE,
            MMCHS_SD_IE_TC_ENABLE_ENABLE);

        /* enable error interrupts */
        /* NOTE: We are currently skipping the BADA interrupt it does get
         * raised for unknown reasons */
        set32(base_address + MMCHS_SD_IE, MMCHS_SD_IE_ERROR_MASK, 0x0fffffffu);

        /* clean the error interrupts */
        set32(base_address + MMCHS_SD_STAT, MMCHS_SD_STAT_ERROR_MASK,
            0xffffffffu);

        /* send a init signal to the host controller. This does not actually
         * send a command to a card manner */
        set32(base_address + MMCHS_SD_CON, MMCHS_SD_CON_INIT,
            MMCHS_SD_CON_INIT_INIT);
        /* command 0 , type other commands not response etc) */
        write32(base_address + MMCHS_SD_CMD, 0x00);

        counter = 0;
        while ((read32(base_address + MMCHS_SD_STAT) & MMCHS_SD_STAT_CC)
            != MMCHS_SD_STAT_CC_RAISED) {
                if (read32(base_address + MMCHS_SD_STAT) & 0x8000) {
                        mmc_log_warn(&log, "%s, error stat  %x\n",
                            __FUNCTION__,
                            read32(base_address + MMCHS_SD_STAT));
                        return 1;
                }
                counter++;
        }

        /* clear the cc interrupt status */
        set32(base_address + MMCHS_SD_STAT, MMCHS_SD_IE_CC_ENABLE,
            MMCHS_SD_IE_CC_ENABLE_ENABLE);

        /* 
         * Set Set SD_CON[1] INIT bit to 0x0 to end the initialization sequence
         */
        set32(base_address + MMCHS_SD_CON, MMCHS_SD_CON_INIT,
            MMCHS_SD_CON_INIT_NOINIT);

        /* Clean the MMCHS_SD_STAT register */
        write32(base_address + MMCHS_SD_STAT, 0xffffffffu);
        return 0;
}

int
mmchs_send_cmd(uint32_t command, uint32_t arg)
{
        int count = 0;

        /* Read current interrupt status and fail it an interrupt is already
         * asserted */
        if ((read32(base_address + MMCHS_SD_STAT) & 0xffffu)) {
                mmc_log_warn(&log, "%s, interrupt already raised stat  %08x\n",
                    __FUNCTION__, read32(base_address + MMCHS_SD_STAT));
                write32(base_address + MMCHS_SD_STAT,
                    MMCHS_SD_IE_CC_ENABLE_CLEAR);
                // return 1;
        }

        /* Set arguments */
        write32(base_address + MMCHS_SD_ARG, arg);
        /* Set command */
        set32(base_address + MMCHS_SD_CMD, MMCHS_SD_CMD_MASK, command);

        /* Wait for completion */
        while ((read32(base_address + MMCHS_SD_STAT) & 0xffffu) == 0x0) {
                count++;
        }

        if (read32(base_address + MMCHS_SD_STAT) & 0x8000) {
                mmc_log_warn(&log, "%s, error stat  %08x\n", __FUNCTION__,
                    read32(base_address + MMCHS_SD_STAT));
                set32(base_address + MMCHS_SD_STAT, MMCHS_SD_STAT_ERROR_MASK,
                    0xffffffffu);
                return 1;
        }

        if ((command & MMCHS_SD_CMD_RSP_TYPE) ==
            MMCHS_SD_CMD_RSP_TYPE_48B_BUSY) {
                /* 
                 * Command with busy response *CAN* also set the TC bit if they exit busy
                 */
                while ((read32(base_address + MMCHS_SD_STAT)
                        & MMCHS_SD_IE_TC_ENABLE_ENABLE) == 0) {
                        count++;
                }
                write32(base_address + MMCHS_SD_STAT,
                    MMCHS_SD_IE_TC_ENABLE_CLEAR);
        }

        /* clear the cc status */
        write32(base_address + MMCHS_SD_STAT, MMCHS_SD_IE_CC_ENABLE_CLEAR);
        return 0;
}

int
mmc_send_cmd(struct mmc_command *c)
{

        /* convert the command to a hsmmc command */
        int ret;
        uint32_t cmd, arg;
        cmd = MMCHS_SD_CMD_INDX_CMD(c->cmd);
        arg = c->args;

        switch (c->resp_type) {
        case RESP_LEN_48_CHK_BUSY:
                cmd |= MMCHS_SD_CMD_RSP_TYPE_48B_BUSY;
                break;
        case RESP_LEN_48:
                cmd |= MMCHS_SD_CMD_RSP_TYPE_48B;
                break;
        case RESP_LEN_136:
                cmd |= MMCHS_SD_CMD_RSP_TYPE_136B;
                break;
        case NO_RESPONSE:
                cmd |= MMCHS_SD_CMD_RSP_TYPE_NO_RESP;
                break;
        default:
                return 1;
        }

        ret = mmchs_send_cmd(cmd, arg);

        /* copy response into cmd->resp */
        switch (c->resp_type) {
        case RESP_LEN_48_CHK_BUSY:
        case RESP_LEN_48:
                c->resp[0] = read32(base_address + MMCHS_SD_RSP10);
                break;
        case RESP_LEN_136:
                c->resp[0] = read32(base_address + MMCHS_SD_RSP10);
                c->resp[1] = read32(base_address + MMCHS_SD_RSP32);
                c->resp[2] = read32(base_address + MMCHS_SD_RSP54);
                c->resp[3] = read32(base_address + MMCHS_SD_RSP76);
                break;
        case NO_RESPONSE:
                break;
        default:
                return 1;
        }

        return ret;
}

static struct mmc_command command;

int
card_goto_idle_state()
{
        command.cmd = MMC_GO_IDLE_STATE;
        command.resp_type = NO_RESPONSE;
        command.args = 0x00;
        if (mmc_send_cmd(&command)) {
                // Failure
                return 1;
        }
        return 0;
}

int
card_identification()
{
        command.cmd = MMC_SEND_EXT_CSD;
        command.resp_type = RESP_LEN_48;
        command.args = MMCHS_SD_ARG_CMD8_VHS | MMCHS_SD_ARG_CMD8_CHECK_PATTERN;

        if (mmc_send_cmd(&command)) {
                // We currently only support 2.0,
                return 1;
        }

        if (!(command.resp[0]
                == (MMCHS_SD_ARG_CMD8_VHS | MMCHS_SD_ARG_CMD8_CHECK_PATTERN))) {
                mmc_log_warn(&log, "%s, check pattern check failed  %08x\n",
                    __FUNCTION__, command.resp[0]);
                return 1;
        }
        return 0;
}

int
card_query_voltage_and_type(struct sd_card_regs *card)
{

        command.cmd = MMC_APP_CMD;
        command.resp_type = RESP_LEN_48;
        command.args = MMC_ARG_RCA(0x0);        /* RCA=0000 */
        if (mmc_send_cmd(&command)) {
                return 1;
        }

        command.cmd = SD_APP_OP_COND;
        command.resp_type = RESP_LEN_48;

        /* 0x1 << 30 == send HCS (Host capacity support) and get OCR register */
        command.args =
            MMC_OCR_3_3V_3_4V | MMC_OCR_3_2V_3_3V | MMC_OCR_3_1V_3_2V |
            MMC_OCR_3_0V_3_1V | MMC_OCR_2_9V_3_0V | MMC_OCR_2_8V_2_9V |
            MMC_OCR_2_7V_2_8V;
        command.args |= MMC_OCR_HCS;    /* RCA=0000 */

        if (mmc_send_cmd(&command)) {
                return 1;
        }
        /* @todo wait for max 1 ms */
        while (!(command.resp[0] & MMC_OCR_MEM_READY)) {
                command.cmd = MMC_APP_CMD;
                command.resp_type = RESP_LEN_48;
                command.args = MMC_ARG_RCA(0x0);        /* RCA=0000 */
                if (mmc_send_cmd(&command)) {
                        return 1;
                }

                /* Send ADMD41 */
                /* 0x1 << 30 == send HCS (Host capacity support) and get OCR
                 * register */
                command.cmd = SD_APP_OP_COND;
                command.resp_type = RESP_LEN_48;
                /* 0x1 << 30 == send HCS (Host capacity support) */
                command.args = MMC_OCR_3_3V_3_4V | MMC_OCR_3_2V_3_3V
                    | MMC_OCR_3_1V_3_2V | MMC_OCR_3_0V_3_1V | MMC_OCR_2_9V_3_0V
                    | MMC_OCR_2_8V_2_9V | MMC_OCR_2_7V_2_8V;
                command.args |= MMC_OCR_HCS;    /* RCA=0000 */

                if (mmc_send_cmd(&command)) {
                        return 1;
                }

                /* if bit 31 is set the response is valid */
                if ((command.resp[0] & MMC_OCR_MEM_READY)) {
                        break;
                }

        }
        card->ocr = command.resp[3];
        return 0;
}

int
card_identify(struct sd_card_regs *card)
{

        /* Send cmd 2 (all_send_cid) and expect 136 bits response */
        command.cmd = MMC_ALL_SEND_CID;
        command.resp_type = RESP_LEN_136;
        command.args = MMC_ARG_RCA(0x0);        /* RCA=0000 */

        if (mmc_send_cmd(&command)) {
                return 1;
        }

        card->cid[0] = command.resp[0];
        card->cid[1] = command.resp[1];
        card->cid[2] = command.resp[2];
        card->cid[3] = command.resp[3];

        command.cmd = MMC_SET_RELATIVE_ADDR;
        command.resp_type = RESP_LEN_48;
        command.args = 0x0;     /* RCA=0000 */

        /* R6 response */
        if (mmc_send_cmd(&command)) {
                return 1;
        }

        card->rca = SD_R6_RCA(command.resp);
        /* MMHCS only supports a single card so sending MMCHS_SD_CMD_CMD2 is
         * useless Still we should make it possible in the API to support
         * multiple cards */

        return 0;
}

int
card_csd(struct sd_card_regs *card)
{
        /* send_csd -> r2 response */
        command.cmd = MMC_SEND_CSD;
        command.resp_type = RESP_LEN_136;
        command.args = MMC_ARG_RCA(card->rca);  /* card rca */

        if (mmc_send_cmd(&command)) {
                return 1;
        }

        card->csd[0] = command.resp[0];
        card->csd[1] = command.resp[1];
        card->csd[2] = command.resp[2];
        card->csd[3] = command.resp[3];

        if (SD_CSD_CSDVER(card->csd) != SD_CSD_CSDVER_2_0) {
                mmc_log_warn(&log, "Version 2.0 of CSD register expected\n");
                return 1;
        }

        /* sanity check */
        // mmc_log_warn(&log,"size = %llu bytes\n", (long long
        // unsigned)SD_CSD_V2_CAPACITY( card->csd) * 512);
        return 0;
}

int
select_card(struct sd_card_regs *card)
{

        command.cmd = MMC_SELECT_CARD;
        command.resp_type = RESP_LEN_48_CHK_BUSY;
        command.args = MMC_ARG_RCA(card->rca);  /* card rca */

        if (mmc_send_cmd(&command)) {
                return 1;
        }
        return 0;
}

int
read_single_block(struct sd_card_regs *card,
    uint32_t blknr, unsigned char *buf)
{
        uint32_t count;
        uint32_t value;

        count = 0;

        set32(base_address + MMCHS_SD_IE, MMCHS_SD_IE_BRR_ENABLE,
            MMCHS_SD_IE_BRR_ENABLE_ENABLE);

        set32(base_address + MMCHS_SD_BLK, MMCHS_SD_BLK_BLEN, 512);

        /* read single block */
        if (mmchs_send_cmd(MMCHS_SD_CMD_INDX_CMD(MMC_READ_BLOCK_SINGLE)
                | MMCHS_SD_CMD_DP_DATA  /* Command with data transfer */
                | MMCHS_SD_CMD_RSP_TYPE_48B     /* type (R1) */
                | MMCHS_SD_CMD_MSBS_SINGLE      /* single block */
                | MMCHS_SD_CMD_DDIR_READ        /* read data from card */
                , blknr)) {
                return 1;
        }

        while ((read32(base_address + MMCHS_SD_STAT)
                & MMCHS_SD_IE_BRR_ENABLE_ENABLE) == 0) {
                count++;
        }

        if (!(read32(base_address + MMCHS_SD_PSTATE) & MMCHS_SD_PSTATE_BRE_EN)) {
                return 1;       /* We are not allowed to read data from the
                                 * data buffer */
        }

        for (count = 0; count < 512; count += 4) {
                value = read32(base_address + MMCHS_SD_DATA);
                buf[count] = *((char *) &value);
                buf[count + 1] = *((char *) &value + 1);
                buf[count + 2] = *((char *) &value + 2);
                buf[count + 3] = *((char *) &value + 3);
        }

        /* Wait for TC */
        while ((read32(base_address +
                    MMCHS_SD_STAT) & MMCHS_SD_IE_TC_ENABLE_ENABLE)
            == 0) {
                count++;
        }
        write32(base_address + MMCHS_SD_STAT, MMCHS_SD_IE_TC_ENABLE_CLEAR);

        /* clear and disable the bbr interrupt */
        write32(base_address + MMCHS_SD_STAT, MMCHS_SD_IE_BRR_ENABLE_CLEAR);
        set32(base_address + MMCHS_SD_IE, MMCHS_SD_IE_BRR_ENABLE,
            MMCHS_SD_IE_BRR_ENABLE_DISABLE);
        return 0;
}

int
write_single_block(struct sd_card_regs *card,
    uint32_t blknr, unsigned char *buf)
{
        uint32_t count;
        uint32_t value;

        count = 0;

        set32(base_address + MMCHS_SD_IE, MMCHS_SD_IE_BWR_ENABLE,
            MMCHS_SD_IE_BWR_ENABLE_ENABLE);
        // set32(base_address + MMCHS_SD_IE, 0xfff , 0xfff);
        set32(base_address + MMCHS_SD_BLK, MMCHS_SD_BLK_BLEN, 512);

        /* Set timeout */
        set32(base_address + MMCHS_SD_SYSCTL, MMCHS_SD_SYSCTL_DTO,
            MMCHS_SD_SYSCTL_DTO_2POW27);

        /* write single block */
        if (mmchs_send_cmd(MMCHS_SD_CMD_INDX_CMD(MMC_WRITE_BLOCK_SINGLE)
                | MMCHS_SD_CMD_DP_DATA  /* Command with data transfer */
                | MMCHS_SD_CMD_RSP_TYPE_48B     /* type (R1b) */
                | MMCHS_SD_CMD_MSBS_SINGLE      /* single block */
                | MMCHS_SD_CMD_DDIR_WRITE       /* write to the card */
                , blknr)) {
                return 1;
        }

        /* Wait for the MMCHS_SD_IE_BWR_ENABLE interrupt */
        while ((read32(base_address +
                    MMCHS_SD_STAT) & MMCHS_SD_IE_BWR_ENABLE) == 0) {
                count++;
        }

        if (!(read32(base_address + MMCHS_SD_PSTATE) & MMCHS_SD_PSTATE_BWE_EN)) {
                return 1;       /* not ready to write data */
        }
        for (count = 0; count < 512; count += 4) {
                *((char *) &value) = buf[count];
                *((char *) &value + 1) = buf[count + 1];
                *((char *) &value + 2) = buf[count + 2];
                *((char *) &value + 3) = buf[count + 3];
                write32(base_address + MMCHS_SD_DATA, value);
        }

        /* Wait for TC */
        while ((read32(base_address +
                    MMCHS_SD_STAT) & MMCHS_SD_IE_TC_ENABLE_ENABLE)
            == 0) {
                count++;
        }
        write32(base_address + MMCHS_SD_STAT, MMCHS_SD_IE_TC_ENABLE_CLEAR);
        write32(base_address + MMCHS_SD_STAT, MMCHS_SD_IE_CC_ENABLE_CLEAR);     /* finished. 
                                                                                 */
        /* clear the bwr interrupt FIXME is this right when writing? */
        write32(base_address + MMCHS_SD_STAT, MMCHS_SD_IE_BWR_ENABLE_CLEAR);
        set32(base_address + MMCHS_SD_IE, MMCHS_SD_IE_BWR_ENABLE,
            MMCHS_SD_IE_BWR_ENABLE_DISABLE);
        return 0;
}

int
mmchs_host_init(struct mmc_host *host)
{
        mmchs_init(1);
        return 0;
}

void
mmchs_set_log_level(int level)
{
        if (level >= 0 && level <= 4) {
                log.log_level = level;
        }
}

int
mmchs_host_set_instance(struct mmc_host *host, int instance)
{
        mmc_log_info(&log, "Using instance number %d\n", instance);
        if (instance != 0) {
                return EIO;
        }
        return OK;
}

int
mmchs_host_reset(struct mmc_host *host)
{
        mmchs_init(1);
        return 0;
}

int
mmchs_card_detect(struct sd_slot *slot)
{
        /* @TODO implement proper card detect */
        return 1;
}

struct sd_card *
mmchs_card_initialize(struct sd_slot *slot)
{
        mmchs_init(1);

        struct sd_card *card;
        card = &slot->card;
        memset(card, 0, sizeof(struct sd_card));
        card->slot = slot;

        if (card_goto_idle_state()) {
                mmc_log_warn(&log, "Failed to go idle state\n");
                return NULL;
        }

        if (card_identification()) {
                mmc_log_warn(&log, "Failed to do card_identification\n");
                return NULL;
        }

        if (card_query_voltage_and_type(&slot->card.regs)) {
                mmc_log_warn(&log,
                    "Failed to do card_query_voltage_and_type\n");
                return NULL;
        }
        if (card_identify(&slot->card.regs)) {
                mmc_log_warn(&log, "Failed to identify card\n");
                return NULL;
        }
        /* We have now initialized the hardware identified the card */
        if (card_csd(&slot->card.regs)) {
                mmc_log_warn(&log,
                    "failed to read csd (card specific data)\n");
                return NULL;
        }

        if (select_card(&slot->card.regs)) {
                mmc_log_warn(&log, "Failed to select card\n");
                return NULL;
        }

        if (SD_CSD_READ_BL_LEN(slot->card.regs.csd) != 0x09) {
                /* for CSD version 2.0 the value is fixed to 0x09 and means a
                 * block size of 512 */
                mmc_log_warn(&log, "Block size expect to be 512\n");
                return NULL;
        }

        slot->card.blk_size = 512;      /* HARDCODED value */
        slot->card.blk_count = SD_CSD_V2_CAPACITY(slot->card.regs.csd);
        slot->card.state = SD_MODE_DATA_TRANSFER_MODE;

        memset(slot->card.part, 0, sizeof(slot->card.part));
        memset(slot->card.subpart, 0, sizeof(slot->card.subpart));
        slot->card.part[0].dv_base = 0;
        slot->card.part[0].dv_size =
            (unsigned long long) SD_CSD_V2_CAPACITY(slot->card.regs.csd) * 512;
        return &slot->card;
}

/* read count blocks into existing buf */
static int
mmchs_host_read(struct sd_card *card,
    uint32_t blknr, uint32_t count, unsigned char *buf)
{
        uint32_t i;
        i = count;
        for (i = 0; i < count; i++) {
                read_single_block(&card->regs, blknr + i,
                    buf + (i * card->blk_size));
        }
        return OK;
}

/* write count blocks */
static int
mmchs_host_write(struct sd_card *card,
    uint32_t blknr, uint32_t count, unsigned char *buf)
{
        uint32_t i;

        i = count;
        for (i = 0; i < count; i++) {
                write_single_block(&card->regs, blknr + i,
                    buf + (i * card->blk_size));
        }

        return OK;
}

int
mmchs_card_release(struct sd_card *card)
{
        assert(card->open_ct == 1);
        card->open_ct--;
        card->state = SD_MODE_UNINITIALIZED;
        /* TODO:Set card state */
        return OK;
}

void
host_initialize_host_structure_mmchs(struct mmc_host *host)
{
        /* Initialize the basic data structures host slots and cards */
        int i;

        host->host_set_instance = mmchs_host_set_instance;
        host->host_init = mmchs_host_init;
        host->set_log_level = mmchs_set_log_level;
        host->host_reset = mmchs_host_reset;
        host->card_detect = mmchs_card_detect;
        host->card_initialize = mmchs_card_initialize;
        host->card_release = mmchs_card_release;
        host->read = mmchs_host_read;
        host->write = mmchs_host_write;

        /* initialize data structures */
        for (i = 0; i < sizeof(host->slot) / sizeof(host->slot[0]); i++) {
                // @TODO set initial card and slot state
                host->slot[i].host = host;
                host->slot[i].card.slot = &host->slot[i];
        }
}