// SPDX-License-Identifier: GPL-2.0-only
/*
 *  cb710/mmc.c
 *
 *  Copyright by Michał Mirosław, 2008-2009
 */
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/delay.h>
#include <linux/string_choices.h>
#include "cb710-mmc.h"

#define CB710_MMC_REQ_TIMEOUT_MS        2000

static const u8 cb710_clock_divider_log2[8] = {
/*      1, 2, 4, 8, 16, 32, 128, 512 */
        0, 1, 2, 3,  4,  5,   7,   9
};
#define CB710_MAX_DIVIDER_IDX   \
        (ARRAY_SIZE(cb710_clock_divider_log2) - 1)

static const u8 cb710_src_freq_mhz[16] = {
        33, 10, 20, 25, 30, 35, 40, 45,
        50, 55, 60, 65, 70, 75, 80, 85
};

static void cb710_mmc_select_clock_divider(struct mmc_host *mmc, int hz)
{
        struct cb710_slot *slot = cb710_mmc_to_slot(mmc);
        struct pci_dev *pdev = cb710_slot_to_chip(slot)->pdev;
        u32 src_freq_idx;
        u32 divider_idx;
        int src_hz;

        /* on CB710 in HP nx9500:
         *   src_freq_idx == 0
         *   indexes 1-7 work as written in the table
         *   indexes 0,8-15 give no clock output
         */
        pci_read_config_dword(pdev, 0x48, &src_freq_idx);
        src_freq_idx = (src_freq_idx >> 16) & 0xF;
        src_hz = cb710_src_freq_mhz[src_freq_idx] * 1000000;

        for (divider_idx = 0; divider_idx < CB710_MAX_DIVIDER_IDX; ++divider_idx) {
                if (hz >= src_hz >> cb710_clock_divider_log2[divider_idx])
                        break;
        }

        if (src_freq_idx)
                divider_idx |= 0x8;
        else if (divider_idx == 0)
                divider_idx = 1;

        cb710_pci_update_config_reg(pdev, 0x40, ~0xF0000000, divider_idx << 28);

        dev_dbg(cb710_slot_dev(slot),
                "clock set to %d Hz, wanted %d Hz; src_freq_idx = %d, divider_idx = %d|%d\n",
                src_hz >> cb710_clock_divider_log2[divider_idx & 7],
                hz, src_freq_idx, divider_idx & 7, divider_idx & 8);
}

static void __cb710_mmc_enable_irq(struct cb710_slot *slot,
        unsigned short enable, unsigned short mask)
{
        /* clear global IE
         * - it gets set later if any interrupt sources are enabled */
        mask |= CB710_MMC_IE_IRQ_ENABLE;

        /* look like interrupt is fired whenever
         * WORD[0x0C] & WORD[0x10] != 0;
         * -> bit 15 port 0x0C seems to be global interrupt enable
         */

        enable = (cb710_read_port_16(slot, CB710_MMC_IRQ_ENABLE_PORT)
                & ~mask) | enable;

        if (enable)
                enable |= CB710_MMC_IE_IRQ_ENABLE;

        cb710_write_port_16(slot, CB710_MMC_IRQ_ENABLE_PORT, enable);
}

static void cb710_mmc_enable_irq(struct cb710_slot *slot,
        unsigned short enable, unsigned short mask)
{
        struct cb710_mmc_reader *reader = mmc_priv(cb710_slot_to_mmc(slot));
        unsigned long flags;

        spin_lock_irqsave(&reader->irq_lock, flags);
        /* this is the only thing irq_lock protects */
        __cb710_mmc_enable_irq(slot, enable, mask);
        spin_unlock_irqrestore(&reader->irq_lock, flags);
}

static void cb710_mmc_reset_events(struct cb710_slot *slot)
{
        cb710_write_port_8(slot, CB710_MMC_STATUS0_PORT, 0xFF);
        cb710_write_port_8(slot, CB710_MMC_STATUS1_PORT, 0xFF);
        cb710_write_port_8(slot, CB710_MMC_STATUS2_PORT, 0xFF);
}

static void cb710_mmc_enable_4bit_data(struct cb710_slot *slot, int enable)
{
        if (enable)
                cb710_modify_port_8(slot, CB710_MMC_CONFIG1_PORT,
                        CB710_MMC_C1_4BIT_DATA_BUS, 0);
        else
                cb710_modify_port_8(slot, CB710_MMC_CONFIG1_PORT,
                        0, CB710_MMC_C1_4BIT_DATA_BUS);
}

static int cb710_check_event(struct cb710_slot *slot, u8 what)
{
        u16 status;

        status = cb710_read_port_16(slot, CB710_MMC_STATUS_PORT);

        if (status & CB710_MMC_S0_FIFO_UNDERFLOW) {
                /* it is just a guess, so log it */
                dev_dbg(cb710_slot_dev(slot),
                        "CHECK : ignoring bit 6 in status %04X\n", status);
                cb710_write_port_8(slot, CB710_MMC_STATUS0_PORT,
                        CB710_MMC_S0_FIFO_UNDERFLOW);
                status &= ~CB710_MMC_S0_FIFO_UNDERFLOW;
        }

        if (status & CB710_MMC_STATUS_ERROR_EVENTS) {
                dev_dbg(cb710_slot_dev(slot),
                        "CHECK : returning EIO on status %04X\n", status);
                cb710_write_port_8(slot, CB710_MMC_STATUS0_PORT, status & 0xFF);
                cb710_write_port_8(slot, CB710_MMC_STATUS1_PORT,
                        CB710_MMC_S1_RESET);
                return -EIO;
        }

        /* 'what' is a bit in MMC_STATUS1 */
        if ((status >> 8) & what) {
                cb710_write_port_8(slot, CB710_MMC_STATUS1_PORT, what);
                return 1;
        }

        return 0;
}

static int cb710_wait_for_event(struct cb710_slot *slot, u8 what)
{
        int err = 0;
        unsigned limit = 2000000;       /* FIXME: real timeout */

#ifdef CONFIG_CB710_DEBUG
        u32 e, x;
        e = cb710_read_port_32(slot, CB710_MMC_STATUS_PORT);
#endif

        while (!(err = cb710_check_event(slot, what))) {
                if (!--limit) {
                        cb710_dump_regs(cb710_slot_to_chip(slot),
                                CB710_DUMP_REGS_MMC);
                        err = -ETIMEDOUT;
                        break;
                }
                udelay(1);
        }

#ifdef CONFIG_CB710_DEBUG
        x = cb710_read_port_32(slot, CB710_MMC_STATUS_PORT);

        limit = 2000000 - limit;
        if (limit > 100)
                dev_dbg(cb710_slot_dev(slot),
                        "WAIT10: waited %d loops, what %d, entry val %08X, exit val %08X\n",
                        limit, what, e, x);
#endif
        return err < 0 ? err : 0;
}


static int cb710_wait_while_busy(struct cb710_slot *slot, uint8_t mask)
{
        unsigned limit = 500000;        /* FIXME: real timeout */
        int err = 0;

#ifdef CONFIG_CB710_DEBUG
        u32 e, x;
        e = cb710_read_port_32(slot, CB710_MMC_STATUS_PORT);
#endif

        while (cb710_read_port_8(slot, CB710_MMC_STATUS2_PORT) & mask) {
                if (!--limit) {
                        cb710_dump_regs(cb710_slot_to_chip(slot),
                                CB710_DUMP_REGS_MMC);
                        err = -ETIMEDOUT;
                        break;
                }
                udelay(1);
        }

#ifdef CONFIG_CB710_DEBUG
        x = cb710_read_port_32(slot, CB710_MMC_STATUS_PORT);

        limit = 500000 - limit;
        if (limit > 100)
                dev_dbg(cb710_slot_dev(slot),
                        "WAIT12: waited %d loops, mask %02X, entry val %08X, exit val %08X\n",
                        limit, mask, e, x);
#endif
        return err;
}

static void cb710_mmc_set_transfer_size(struct cb710_slot *slot,
        size_t count, size_t blocksize)
{
        cb710_wait_while_busy(slot, CB710_MMC_S2_BUSY_20);
        cb710_write_port_32(slot, CB710_MMC_TRANSFER_SIZE_PORT,
                ((count - 1) << 16)|(blocksize - 1));

        dev_vdbg(cb710_slot_dev(slot), "set up for %zu block%s of %zu bytes\n",
                count, str_plural(count), blocksize);
}

static void cb710_mmc_fifo_hack(struct cb710_slot *slot)
{
        /* without this, received data is prepended with 8-bytes of zeroes */
        u32 r1, r2;
        int ok = 0;

        r1 = cb710_read_port_32(slot, CB710_MMC_DATA_PORT);
        r2 = cb710_read_port_32(slot, CB710_MMC_DATA_PORT);
        if (cb710_read_port_8(slot, CB710_MMC_STATUS0_PORT)
            & CB710_MMC_S0_FIFO_UNDERFLOW) {
                cb710_write_port_8(slot, CB710_MMC_STATUS0_PORT,
                        CB710_MMC_S0_FIFO_UNDERFLOW);
                ok = 1;
        }

        dev_dbg(cb710_slot_dev(slot),
                "FIFO-read-hack: expected STATUS0 bit was %s\n",
                ok ? "set." : "NOT SET!");
        dev_dbg(cb710_slot_dev(slot),
                "FIFO-read-hack: dwords ignored: %08X %08X - %s\n",
                r1, r2, (r1|r2) ? "BAD (NOT ZERO)!" : "ok");
}

static int cb710_mmc_receive_pio(struct cb710_slot *slot,
        struct sg_mapping_iter *miter, size_t dw_count)
{
        if (!(cb710_read_port_8(slot, CB710_MMC_STATUS2_PORT) & CB710_MMC_S2_FIFO_READY)) {
                int err = cb710_wait_for_event(slot,
                        CB710_MMC_S1_PIO_TRANSFER_DONE);
                if (err)
                        return err;
        }

        cb710_sg_dwiter_write_from_io(miter,
                slot->iobase + CB710_MMC_DATA_PORT, dw_count);

        return 0;
}

static bool cb710_is_transfer_size_supported(struct mmc_data *data)
{
        return !(data->blksz & 15 && (data->blocks != 1 || data->blksz != 8));
}

static int cb710_mmc_receive(struct cb710_slot *slot, struct mmc_data *data)
{
        struct sg_mapping_iter miter;
        size_t len, blocks = data->blocks;
        int err = 0;

        /* TODO: I don't know how/if the hardware handles non-16B-boundary blocks
         * except single 8B block */
        if (unlikely(data->blksz & 15 && (data->blocks != 1 || data->blksz != 8)))
                return -EINVAL;

        sg_miter_start(&miter, data->sg, data->sg_len, SG_MITER_TO_SG);

        cb710_modify_port_8(slot, CB710_MMC_CONFIG2_PORT,
                15, CB710_MMC_C2_READ_PIO_SIZE_MASK);

        cb710_mmc_fifo_hack(slot);

        while (blocks-- > 0) {
                len = data->blksz;

                while (len >= 16) {
                        err = cb710_mmc_receive_pio(slot, &miter, 4);
                        if (err)
                                goto out;
                        len -= 16;
                }

                if (!len)
                        continue;

                cb710_modify_port_8(slot, CB710_MMC_CONFIG2_PORT,
                        len - 1, CB710_MMC_C2_READ_PIO_SIZE_MASK);

                len = (len >= 8) ? 4 : 2;
                err = cb710_mmc_receive_pio(slot, &miter, len);
                if (err)
                        goto out;
        }
out:
        sg_miter_stop(&miter);
        return err;
}

static int cb710_mmc_send(struct cb710_slot *slot, struct mmc_data *data)
{
        struct sg_mapping_iter miter;
        size_t len, blocks = data->blocks;
        int err = 0;

        /* TODO: I don't know how/if the hardware handles multiple
         * non-16B-boundary blocks */
        if (unlikely(data->blocks > 1 && data->blksz & 15))
                return -EINVAL;

        sg_miter_start(&miter, data->sg, data->sg_len, SG_MITER_FROM_SG);

        cb710_modify_port_8(slot, CB710_MMC_CONFIG2_PORT,
                0, CB710_MMC_C2_READ_PIO_SIZE_MASK);

        while (blocks-- > 0) {
                len = (data->blksz + 15) >> 4;
                do {
                        if (!(cb710_read_port_8(slot, CB710_MMC_STATUS2_PORT)
                            & CB710_MMC_S2_FIFO_EMPTY)) {
                                err = cb710_wait_for_event(slot,
                                        CB710_MMC_S1_PIO_TRANSFER_DONE);
                                if (err)
                                        goto out;
                        }
                        cb710_sg_dwiter_read_to_io(&miter,
                                slot->iobase + CB710_MMC_DATA_PORT, 4);
                } while (--len);
        }
out:
        sg_miter_stop(&miter);
        return err;
}

static u16 cb710_encode_cmd_flags(struct cb710_mmc_reader *reader,
        struct mmc_command *cmd)
{
        unsigned int flags = cmd->flags;
        u16 cb_flags = 0;

        /* Windows driver returned 0 for commands for which no response
         * is expected. It happened that there were only two such commands
         * used: MMC_GO_IDLE_STATE and MMC_GO_INACTIVE_STATE so it might
         * as well be a bug in that driver.
         *
         * Original driver set bit 14 for MMC/SD application
         * commands. There's no difference 'on the wire' and
         * it apparently works without it anyway.
         */

        switch (flags & MMC_CMD_MASK) {
        case MMC_CMD_AC:        cb_flags = CB710_MMC_CMD_AC;    break;
        case MMC_CMD_ADTC:      cb_flags = CB710_MMC_CMD_ADTC;  break;
        case MMC_CMD_BC:        cb_flags = CB710_MMC_CMD_BC;    break;
        case MMC_CMD_BCR:       cb_flags = CB710_MMC_CMD_BCR;   break;
        }

        if (flags & MMC_RSP_BUSY)
                cb_flags |= CB710_MMC_RSP_BUSY;

        cb_flags |= cmd->opcode << CB710_MMC_CMD_CODE_SHIFT;

        if (cmd->data && (cmd->data->flags & MMC_DATA_READ))
                cb_flags |= CB710_MMC_DATA_READ;

        if (flags & MMC_RSP_PRESENT) {
                /* Windows driver set 01 at bits 4,3 except for
                 * MMC_SET_BLOCKLEN where it set 10. Maybe the
                 * hardware can do something special about this
                 * command? The original driver looks buggy/incomplete
                 * anyway so we ignore this for now.
                 *
                 * I assume that 00 here means no response is expected.
                 */
                cb_flags |= CB710_MMC_RSP_PRESENT;

                if (flags & MMC_RSP_136)
                        cb_flags |= CB710_MMC_RSP_136;
                if (!(flags & MMC_RSP_CRC))
                        cb_flags |= CB710_MMC_RSP_NO_CRC;
        }

        return cb_flags;
}

static void cb710_receive_response(struct cb710_slot *slot,
        struct mmc_command *cmd)
{
        unsigned rsp_opcode, wanted_opcode;

        /* Looks like final byte with CRC is always stripped (same as SDHCI) */
        if (cmd->flags & MMC_RSP_136) {
                u32 resp[4];

                resp[0] = cb710_read_port_32(slot, CB710_MMC_RESPONSE3_PORT);
                resp[1] = cb710_read_port_32(slot, CB710_MMC_RESPONSE2_PORT);
                resp[2] = cb710_read_port_32(slot, CB710_MMC_RESPONSE1_PORT);
                resp[3] = cb710_read_port_32(slot, CB710_MMC_RESPONSE0_PORT);
                rsp_opcode = resp[0] >> 24;

                cmd->resp[0] = (resp[0] << 8)|(resp[1] >> 24);
                cmd->resp[1] = (resp[1] << 8)|(resp[2] >> 24);
                cmd->resp[2] = (resp[2] << 8)|(resp[3] >> 24);
                cmd->resp[3] = (resp[3] << 8);
        } else {
                rsp_opcode = cb710_read_port_32(slot, CB710_MMC_RESPONSE1_PORT) & 0x3F;
                cmd->resp[0] = cb710_read_port_32(slot, CB710_MMC_RESPONSE0_PORT);
        }

        wanted_opcode = (cmd->flags & MMC_RSP_OPCODE) ? cmd->opcode : 0x3F;
        if (rsp_opcode != wanted_opcode)
                cmd->error = -EILSEQ;
}

static int cb710_mmc_transfer_data(struct cb710_slot *slot,
        struct mmc_data *data)
{
        int error, to;

        if (data->flags & MMC_DATA_READ)
                error = cb710_mmc_receive(slot, data);
        else
                error = cb710_mmc_send(slot, data);

        to = cb710_wait_for_event(slot, CB710_MMC_S1_DATA_TRANSFER_DONE);
        if (!error)
                error = to;

        if (!error)
                data->bytes_xfered = data->blksz * data->blocks;
        return error;
}

static int cb710_mmc_command(struct mmc_host *mmc, struct mmc_command *cmd)
{
        struct cb710_slot *slot = cb710_mmc_to_slot(mmc);
        struct cb710_mmc_reader *reader = mmc_priv(mmc);
        struct mmc_data *data = cmd->data;

        u16 cb_cmd = cb710_encode_cmd_flags(reader, cmd);
        dev_dbg(cb710_slot_dev(slot), "cmd request: 0x%04X\n", cb_cmd);

        if (data) {
                if (!cb710_is_transfer_size_supported(data)) {
                        data->error = -EINVAL;
                        return -1;
                }
                cb710_mmc_set_transfer_size(slot, data->blocks, data->blksz);
        }

        cb710_wait_while_busy(slot, CB710_MMC_S2_BUSY_20|CB710_MMC_S2_BUSY_10);
        cb710_write_port_16(slot, CB710_MMC_CMD_TYPE_PORT, cb_cmd);
        cb710_wait_while_busy(slot, CB710_MMC_S2_BUSY_20);
        cb710_write_port_32(slot, CB710_MMC_CMD_PARAM_PORT, cmd->arg);
        cb710_mmc_reset_events(slot);
        cb710_wait_while_busy(slot, CB710_MMC_S2_BUSY_20);
        cb710_modify_port_8(slot, CB710_MMC_CONFIG0_PORT, 0x01, 0);

        cmd->error = cb710_wait_for_event(slot, CB710_MMC_S1_COMMAND_SENT);
        if (cmd->error)
                return -1;

        if (cmd->flags & MMC_RSP_PRESENT) {
                cb710_receive_response(slot, cmd);
                if (cmd->error)
                        return -1;
        }

        if (data)
                data->error = cb710_mmc_transfer_data(slot, data);
        return 0;
}

static void cb710_mmc_request(struct mmc_host *mmc, struct mmc_request *mrq)
{
        struct cb710_slot *slot = cb710_mmc_to_slot(mmc);
        struct cb710_mmc_reader *reader = mmc_priv(mmc);

        WARN_ON(reader->mrq != NULL);

        reader->mrq = mrq;
        cb710_mmc_enable_irq(slot, CB710_MMC_IE_TEST_MASK, 0);

        if (!cb710_mmc_command(mmc, mrq->cmd) && mrq->stop)
                cb710_mmc_command(mmc, mrq->stop);

        queue_work(system_bh_wq, &reader->finish_req_bh_work);
}

static int cb710_mmc_powerup(struct cb710_slot *slot)
{
#ifdef CONFIG_CB710_DEBUG
        struct cb710_chip *chip = cb710_slot_to_chip(slot);
#endif
        int err;

        /* a lot of magic for now */
        dev_dbg(cb710_slot_dev(slot), "bus powerup\n");
        cb710_dump_regs(chip, CB710_DUMP_REGS_MMC);
        err = cb710_wait_while_busy(slot, CB710_MMC_S2_BUSY_20);
        if (unlikely(err))
                return err;
        cb710_modify_port_8(slot, CB710_MMC_CONFIG1_PORT, 0x80, 0);
        cb710_modify_port_8(slot, CB710_MMC_CONFIG3_PORT, 0x80, 0);
        cb710_dump_regs(chip, CB710_DUMP_REGS_MMC);
        mdelay(1);
        dev_dbg(cb710_slot_dev(slot), "after delay 1\n");
        cb710_dump_regs(chip, CB710_DUMP_REGS_MMC);
        err = cb710_wait_while_busy(slot, CB710_MMC_S2_BUSY_20);
        if (unlikely(err))
                return err;
        cb710_modify_port_8(slot, CB710_MMC_CONFIG1_PORT, 0x09, 0);
        cb710_dump_regs(chip, CB710_DUMP_REGS_MMC);
        mdelay(1);
        dev_dbg(cb710_slot_dev(slot), "after delay 2\n");
        cb710_dump_regs(chip, CB710_DUMP_REGS_MMC);
        err = cb710_wait_while_busy(slot, CB710_MMC_S2_BUSY_20);
        if (unlikely(err))
                return err;
        cb710_modify_port_8(slot, CB710_MMC_CONFIG1_PORT, 0, 0x08);
        cb710_dump_regs(chip, CB710_DUMP_REGS_MMC);
        mdelay(2);
        dev_dbg(cb710_slot_dev(slot), "after delay 3\n");
        cb710_dump_regs(chip, CB710_DUMP_REGS_MMC);
        cb710_modify_port_8(slot, CB710_MMC_CONFIG0_PORT, 0x06, 0);
        cb710_modify_port_8(slot, CB710_MMC_CONFIG1_PORT, 0x70, 0);
        cb710_modify_port_8(slot, CB710_MMC_CONFIG2_PORT, 0x80, 0);
        cb710_modify_port_8(slot, CB710_MMC_CONFIG3_PORT, 0x03, 0);
        cb710_dump_regs(chip, CB710_DUMP_REGS_MMC);
        err = cb710_wait_while_busy(slot, CB710_MMC_S2_BUSY_20);
        if (unlikely(err))
                return err;
        /* This port behaves weird: quick byte reads of 0x08,0x09 return
         * 0xFF,0x00 after writing 0xFFFF to 0x08; it works correctly when
         * read/written from userspace...  What am I missing here?
         * (it doesn't depend on write-to-read delay) */
        cb710_write_port_16(slot, CB710_MMC_CONFIGB_PORT, 0xFFFF);
        cb710_modify_port_8(slot, CB710_MMC_CONFIG0_PORT, 0x06, 0);
        cb710_dump_regs(chip, CB710_DUMP_REGS_MMC);
        dev_dbg(cb710_slot_dev(slot), "bus powerup finished\n");

        return cb710_check_event(slot, 0);
}

static void cb710_mmc_powerdown(struct cb710_slot *slot)
{
        cb710_modify_port_8(slot, CB710_MMC_CONFIG1_PORT, 0, 0x81);
        cb710_modify_port_8(slot, CB710_MMC_CONFIG3_PORT, 0, 0x80);
}

static void cb710_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
{
        struct cb710_slot *slot = cb710_mmc_to_slot(mmc);
        struct cb710_mmc_reader *reader = mmc_priv(mmc);
        int err;

        cb710_mmc_select_clock_divider(mmc, ios->clock);

        if (ios->power_mode != reader->last_power_mode) {
                switch (ios->power_mode) {
                case MMC_POWER_ON:
                        err = cb710_mmc_powerup(slot);
                        if (err) {
                                dev_warn(cb710_slot_dev(slot),
                                        "powerup failed (%d)- retrying\n", err);
                                cb710_mmc_powerdown(slot);
                                udelay(1);
                                err = cb710_mmc_powerup(slot);
                                if (err)
                                        dev_warn(cb710_slot_dev(slot),
                                                "powerup retry failed (%d) - expect errors\n",
                                        err);
                        }
                        reader->last_power_mode = MMC_POWER_ON;
                        break;
                case MMC_POWER_OFF:
                        cb710_mmc_powerdown(slot);
                        reader->last_power_mode = MMC_POWER_OFF;
                        break;
                case MMC_POWER_UP:
                default:
                        /* ignore */
                        break;
                }
        }

        cb710_mmc_enable_4bit_data(slot, ios->bus_width != MMC_BUS_WIDTH_1);

        cb710_mmc_enable_irq(slot, CB710_MMC_IE_TEST_MASK, 0);
}

static int cb710_mmc_get_ro(struct mmc_host *mmc)
{
        struct cb710_slot *slot = cb710_mmc_to_slot(mmc);

        return cb710_read_port_8(slot, CB710_MMC_STATUS3_PORT)
                & CB710_MMC_S3_WRITE_PROTECTED;
}

static int cb710_mmc_get_cd(struct mmc_host *mmc)
{
        struct cb710_slot *slot = cb710_mmc_to_slot(mmc);

        return cb710_read_port_8(slot, CB710_MMC_STATUS3_PORT)
                & CB710_MMC_S3_CARD_DETECTED;
}

static int cb710_mmc_irq_handler(struct cb710_slot *slot)
{
        struct mmc_host *mmc = cb710_slot_to_mmc(slot);
        struct cb710_mmc_reader *reader = mmc_priv(mmc);
        u32 status, config1, config2, irqen;

        status = cb710_read_port_32(slot, CB710_MMC_STATUS_PORT);
        irqen = cb710_read_port_32(slot, CB710_MMC_IRQ_ENABLE_PORT);
        config2 = cb710_read_port_32(slot, CB710_MMC_CONFIGB_PORT);
        config1 = cb710_read_port_32(slot, CB710_MMC_CONFIG_PORT);

        dev_dbg(cb710_slot_dev(slot), "interrupt; status: %08X, "
                "ie: %08X, c2: %08X, c1: %08X\n",
                status, irqen, config2, config1);

        if (status & (CB710_MMC_S1_CARD_CHANGED << 8)) {
                /* ack the event */
                cb710_write_port_8(slot, CB710_MMC_STATUS1_PORT,
                        CB710_MMC_S1_CARD_CHANGED);
                if ((irqen & CB710_MMC_IE_CISTATUS_MASK)
                    == CB710_MMC_IE_CISTATUS_MASK)
                        mmc_detect_change(mmc, HZ/5);
        } else {
                dev_dbg(cb710_slot_dev(slot), "unknown interrupt (test)\n");
                spin_lock(&reader->irq_lock);
                __cb710_mmc_enable_irq(slot, 0, CB710_MMC_IE_TEST_MASK);
                spin_unlock(&reader->irq_lock);
        }

        return 1;
}

static void cb710_mmc_finish_request_bh_work(struct work_struct *t)
{
        struct cb710_mmc_reader *reader = from_work(reader, t,
                                                       finish_req_bh_work);
        struct mmc_request *mrq = reader->mrq;

        reader->mrq = NULL;
        mmc_request_done(mmc_from_priv(reader), mrq);
}

static const struct mmc_host_ops cb710_mmc_host = {
        .request = cb710_mmc_request,
        .set_ios = cb710_mmc_set_ios,
        .get_ro = cb710_mmc_get_ro,
        .get_cd = cb710_mmc_get_cd,
};

static int cb710_mmc_suspend(struct device *dev)
{
        struct platform_device *pdev = to_platform_device(dev);
        struct cb710_slot *slot = cb710_pdev_to_slot(pdev);

        cb710_mmc_enable_irq(slot, 0, ~0);
        return 0;
}

static int cb710_mmc_resume(struct device *dev)
{
        struct platform_device *pdev = to_platform_device(dev);
        struct cb710_slot *slot = cb710_pdev_to_slot(pdev);

        cb710_mmc_enable_irq(slot, 0, ~0);
        return 0;
}

static DEFINE_SIMPLE_DEV_PM_OPS(cb710_mmc_pmops, cb710_mmc_suspend, cb710_mmc_resume);

static int cb710_mmc_init(struct platform_device *pdev)
{
        struct cb710_slot *slot = cb710_pdev_to_slot(pdev);
        struct cb710_chip *chip = cb710_slot_to_chip(slot);
        struct mmc_host *mmc;
        struct cb710_mmc_reader *reader;
        int err;
        u32 val;

        mmc = devm_mmc_alloc_host(cb710_slot_dev(slot), sizeof(*reader));
        if (!mmc)
                return -ENOMEM;

        platform_set_drvdata(pdev, mmc);

        /* harmless (maybe) magic */
        pci_read_config_dword(chip->pdev, 0x48, &val);
        val = cb710_src_freq_mhz[(val >> 16) & 0xF];
        dev_dbg(cb710_slot_dev(slot), "source frequency: %dMHz\n", val);
        val *= 1000000;

        mmc->ops = &cb710_mmc_host;
        mmc->f_max = val;
        mmc->f_min = val >> cb710_clock_divider_log2[CB710_MAX_DIVIDER_IDX];
        mmc->ocr_avail = MMC_VDD_32_33|MMC_VDD_33_34;
        mmc->caps = MMC_CAP_4_BIT_DATA;
        /*
         * In cb710_wait_for_event() we use a fixed timeout of ~2s, hence let's
         * inform the core about it. A future improvement should instead make
         * use of the cmd->busy_timeout.
         */
        mmc->max_busy_timeout = CB710_MMC_REQ_TIMEOUT_MS;

        reader = mmc_priv(mmc);

        INIT_WORK(&reader->finish_req_bh_work,
                        cb710_mmc_finish_request_bh_work);
        spin_lock_init(&reader->irq_lock);
        cb710_dump_regs(chip, CB710_DUMP_REGS_MMC);

        cb710_mmc_enable_irq(slot, 0, ~0);
        cb710_set_irq_handler(slot, cb710_mmc_irq_handler);

        err = mmc_add_host(mmc);
        if (unlikely(err))
                goto err_free_mmc;

        dev_dbg(cb710_slot_dev(slot), "mmc_hostname is %s\n",
                mmc_hostname(mmc));

        cb710_mmc_enable_irq(slot, CB710_MMC_IE_CARD_INSERTION_STATUS, 0);

        return 0;

err_free_mmc:
        dev_dbg(cb710_slot_dev(slot), "mmc_add_host() failed: %d\n", err);

        cb710_set_irq_handler(slot, NULL);
        return err;
}

static void cb710_mmc_exit(struct platform_device *pdev)
{
        struct cb710_slot *slot = cb710_pdev_to_slot(pdev);
        struct mmc_host *mmc = cb710_slot_to_mmc(slot);
        struct cb710_mmc_reader *reader = mmc_priv(mmc);

        cb710_mmc_enable_irq(slot, 0, CB710_MMC_IE_CARD_INSERTION_STATUS);

        mmc_remove_host(mmc);

        /* IRQs should be disabled now, but let's stay on the safe side */
        cb710_mmc_enable_irq(slot, 0, ~0);
        cb710_set_irq_handler(slot, NULL);

        /* clear config ports - just in case */
        cb710_write_port_32(slot, CB710_MMC_CONFIG_PORT, 0);
        cb710_write_port_16(slot, CB710_MMC_CONFIGB_PORT, 0);

        cancel_work_sync(&reader->finish_req_bh_work);
}

static struct platform_driver cb710_mmc_driver = {
        .driver = {
                .name = "cb710-mmc",
                .pm = pm_sleep_ptr(&cb710_mmc_pmops),
        },
        .probe = cb710_mmc_init,
        .remove = cb710_mmc_exit,
};

module_platform_driver(cb710_mmc_driver);

MODULE_AUTHOR("Michał Mirosław <mirq-linux@rere.qmqm.pl>");
MODULE_DESCRIPTION("ENE CB710 memory card reader driver - MMC/SD part");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:cb710-mmc");