Merge tag 'v5.0-rockchip-dts64fixes-1' of git://git.kernel.org/pub/scm/linux/kernel...

[mirror_ubuntu-eoan-kernel.git] / drivers / mmc / host / meson-gx-mmc.c

/*
 * Amlogic SD/eMMC driver for the GX/S905 family SoCs
 *
 * Copyright (c) 2016 BayLibre, SAS.
 * Author: Kevin Hilman <khilman@baylibre.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see <http://www.gnu.org/licenses/>.
 * The full GNU General Public License is included in this distribution
 * in the file called COPYING.
 */
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/ioport.h>
#include <linux/dma-mapping.h>
#include <linux/mmc/host.h>
#include <linux/mmc/mmc.h>
#include <linux/mmc/sdio.h>
#include <linux/mmc/slot-gpio.h>
#include <linux/io.h>
#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/regulator/consumer.h>
#include <linux/reset.h>
#include <linux/interrupt.h>
#include <linux/bitfield.h>
#include <linux/pinctrl/consumer.h>

#define DRIVER_NAME "meson-gx-mmc"

#define SD_EMMC_CLOCK 0x0
#define   CLK_DIV_MASK GENMASK(5, 0)
#define   CLK_SRC_MASK GENMASK(7, 6)
#define   CLK_CORE_PHASE_MASK GENMASK(9, 8)
#define   CLK_TX_PHASE_MASK GENMASK(11, 10)
#define   CLK_RX_PHASE_MASK GENMASK(13, 12)
#define   CLK_V2_TX_DELAY_MASK GENMASK(19, 16)
#define   CLK_V2_RX_DELAY_MASK GENMASK(23, 20)
#define   CLK_V2_ALWAYS_ON BIT(24)

#define   CLK_V3_TX_DELAY_MASK GENMASK(21, 16)
#define   CLK_V3_RX_DELAY_MASK GENMASK(27, 22)
#define   CLK_V3_ALWAYS_ON BIT(28)

#define   CLK_DELAY_STEP_PS 200
#define   CLK_PHASE_STEP 30
#define   CLK_PHASE_POINT_NUM (360 / CLK_PHASE_STEP)

#define   CLK_TX_DELAY_MASK(h)          (h->data->tx_delay_mask)
#define   CLK_RX_DELAY_MASK(h)          (h->data->rx_delay_mask)
#define   CLK_ALWAYS_ON(h)              (h->data->always_on)

#define SD_EMMC_DELAY 0x4
#define SD_EMMC_ADJUST 0x8
#define   ADJUST_ADJ_DELAY_MASK GENMASK(21, 16)
#define   ADJUST_DS_EN BIT(15)
#define   ADJUST_ADJ_EN BIT(13)

#define SD_EMMC_DELAY1 0x4
#define SD_EMMC_DELAY2 0x8
#define SD_EMMC_V3_ADJUST 0xc

#define SD_EMMC_CALOUT 0x10
#define SD_EMMC_START 0x40
#define   START_DESC_INIT BIT(0)
#define   START_DESC_BUSY BIT(1)
#define   START_DESC_ADDR_MASK GENMASK(31, 2)

#define SD_EMMC_CFG 0x44
#define   CFG_BUS_WIDTH_MASK GENMASK(1, 0)
#define   CFG_BUS_WIDTH_1 0x0
#define   CFG_BUS_WIDTH_4 0x1
#define   CFG_BUS_WIDTH_8 0x2
#define   CFG_DDR BIT(2)
#define   CFG_BLK_LEN_MASK GENMASK(7, 4)
#define   CFG_RESP_TIMEOUT_MASK GENMASK(11, 8)
#define   CFG_RC_CC_MASK GENMASK(15, 12)
#define   CFG_STOP_CLOCK BIT(22)
#define   CFG_CLK_ALWAYS_ON BIT(18)
#define   CFG_CHK_DS BIT(20)
#define   CFG_AUTO_CLK BIT(23)
#define   CFG_ERR_ABORT BIT(27)

#define SD_EMMC_STATUS 0x48
#define   STATUS_BUSY BIT(31)
#define   STATUS_DESC_BUSY BIT(30)
#define   STATUS_DATI GENMASK(23, 16)

#define SD_EMMC_IRQ_EN 0x4c
#define   IRQ_RXD_ERR_MASK GENMASK(7, 0)
#define   IRQ_TXD_ERR BIT(8)
#define   IRQ_DESC_ERR BIT(9)
#define   IRQ_RESP_ERR BIT(10)
#define   IRQ_CRC_ERR \
        (IRQ_RXD_ERR_MASK | IRQ_TXD_ERR | IRQ_DESC_ERR | IRQ_RESP_ERR)
#define   IRQ_RESP_TIMEOUT BIT(11)
#define   IRQ_DESC_TIMEOUT BIT(12)
#define   IRQ_TIMEOUTS \
        (IRQ_RESP_TIMEOUT | IRQ_DESC_TIMEOUT)
#define   IRQ_END_OF_CHAIN BIT(13)
#define   IRQ_RESP_STATUS BIT(14)
#define   IRQ_SDIO BIT(15)
#define   IRQ_EN_MASK \
        (IRQ_CRC_ERR | IRQ_TIMEOUTS | IRQ_END_OF_CHAIN | IRQ_RESP_STATUS |\
         IRQ_SDIO)

#define SD_EMMC_CMD_CFG 0x50
#define SD_EMMC_CMD_ARG 0x54
#define SD_EMMC_CMD_DAT 0x58
#define SD_EMMC_CMD_RSP 0x5c
#define SD_EMMC_CMD_RSP1 0x60
#define SD_EMMC_CMD_RSP2 0x64
#define SD_EMMC_CMD_RSP3 0x68

#define SD_EMMC_RXD 0x94
#define SD_EMMC_TXD 0x94
#define SD_EMMC_LAST_REG SD_EMMC_TXD

#define SD_EMMC_CFG_BLK_SIZE 512 /* internal buffer max: 512 bytes */
#define SD_EMMC_CFG_RESP_TIMEOUT 256 /* in clock cycles */
#define SD_EMMC_CMD_TIMEOUT 1024 /* in ms */
#define SD_EMMC_CMD_TIMEOUT_DATA 4096 /* in ms */
#define SD_EMMC_CFG_CMD_GAP 16 /* in clock cycles */
#define SD_EMMC_DESC_BUF_LEN PAGE_SIZE

#define SD_EMMC_PRE_REQ_DONE BIT(0)
#define SD_EMMC_DESC_CHAIN_MODE BIT(1)

#define MUX_CLK_NUM_PARENTS 2

struct meson_mmc_data {
        unsigned int tx_delay_mask;
        unsigned int rx_delay_mask;
        unsigned int always_on;
        unsigned int adjust;
};

struct sd_emmc_desc {
        u32 cmd_cfg;
        u32 cmd_arg;
        u32 cmd_data;
        u32 cmd_resp;
};

struct meson_host {
        struct  device          *dev;
        struct  meson_mmc_data *data;
        struct  mmc_host        *mmc;
        struct  mmc_command     *cmd;

        void __iomem *regs;
        struct clk *core_clk;
        struct clk *mmc_clk;
        struct clk *rx_clk;
        struct clk *tx_clk;
        unsigned long req_rate;

        struct pinctrl *pinctrl;
        struct pinctrl_state *pins_default;
        struct pinctrl_state *pins_clk_gate;

        unsigned int bounce_buf_size;
        void *bounce_buf;
        dma_addr_t bounce_dma_addr;
        struct sd_emmc_desc *descs;
        dma_addr_t descs_dma_addr;

        int irq;

        bool vqmmc_enabled;
};

#define CMD_CFG_LENGTH_MASK GENMASK(8, 0)
#define CMD_CFG_BLOCK_MODE BIT(9)
#define CMD_CFG_R1B BIT(10)
#define CMD_CFG_END_OF_CHAIN BIT(11)
#define CMD_CFG_TIMEOUT_MASK GENMASK(15, 12)
#define CMD_CFG_NO_RESP BIT(16)
#define CMD_CFG_NO_CMD BIT(17)
#define CMD_CFG_DATA_IO BIT(18)
#define CMD_CFG_DATA_WR BIT(19)
#define CMD_CFG_RESP_NOCRC BIT(20)
#define CMD_CFG_RESP_128 BIT(21)
#define CMD_CFG_RESP_NUM BIT(22)
#define CMD_CFG_DATA_NUM BIT(23)
#define CMD_CFG_CMD_INDEX_MASK GENMASK(29, 24)
#define CMD_CFG_ERROR BIT(30)
#define CMD_CFG_OWNER BIT(31)

#define CMD_DATA_MASK GENMASK(31, 2)
#define CMD_DATA_BIG_ENDIAN BIT(1)
#define CMD_DATA_SRAM BIT(0)
#define CMD_RESP_MASK GENMASK(31, 1)
#define CMD_RESP_SRAM BIT(0)

struct meson_mmc_phase {
        struct clk_hw hw;
        void __iomem *reg;
        unsigned long phase_mask;
        unsigned long delay_mask;
        unsigned int delay_step_ps;
};

#define to_meson_mmc_phase(_hw) container_of(_hw, struct meson_mmc_phase, hw)

static int meson_mmc_clk_get_phase(struct clk_hw *hw)
{
        struct meson_mmc_phase *mmc = to_meson_mmc_phase(hw);
        unsigned int phase_num = 1 <<  hweight_long(mmc->phase_mask);
        unsigned long period_ps, p, d;
                int degrees;
        u32 val;

        val = readl(mmc->reg);
        p = (val & mmc->phase_mask) >> __ffs(mmc->phase_mask);
        degrees = p * 360 / phase_num;

        if (mmc->delay_mask) {
                period_ps = DIV_ROUND_UP((unsigned long)NSEC_PER_SEC * 1000,
                                         clk_get_rate(hw->clk));
                d = (val & mmc->delay_mask) >> __ffs(mmc->delay_mask);
                degrees += d * mmc->delay_step_ps * 360 / period_ps;
                degrees %= 360;
        }

        return degrees;
}

static void meson_mmc_apply_phase_delay(struct meson_mmc_phase *mmc,
                                        unsigned int phase,
                                        unsigned int delay)
{
        u32 val;

        val = readl(mmc->reg);
        val &= ~mmc->phase_mask;
        val |= phase << __ffs(mmc->phase_mask);

        if (mmc->delay_mask) {
                val &= ~mmc->delay_mask;
                val |= delay << __ffs(mmc->delay_mask);
        }

        writel(val, mmc->reg);
}

static int meson_mmc_clk_set_phase(struct clk_hw *hw, int degrees)
{
        struct meson_mmc_phase *mmc = to_meson_mmc_phase(hw);
        unsigned int phase_num = 1 <<  hweight_long(mmc->phase_mask);
        unsigned long period_ps, d = 0, r;
        uint64_t p;

        p = degrees % 360;

        if (!mmc->delay_mask) {
                p = DIV_ROUND_CLOSEST_ULL(p, 360 / phase_num);
        } else {
                period_ps = DIV_ROUND_UP((unsigned long)NSEC_PER_SEC * 1000,
                                         clk_get_rate(hw->clk));

                /* First compute the phase index (p), the remainder (r) is the
                 * part we'll try to acheive using the delays (d).
                 */
                r = do_div(p, 360 / phase_num);
                d = DIV_ROUND_CLOSEST(r * period_ps,
                                      360 * mmc->delay_step_ps);
                d = min(d, mmc->delay_mask >> __ffs(mmc->delay_mask));
        }

        meson_mmc_apply_phase_delay(mmc, p, d);
        return 0;
}

static const struct clk_ops meson_mmc_clk_phase_ops = {
        .get_phase = meson_mmc_clk_get_phase,
        .set_phase = meson_mmc_clk_set_phase,
};

static unsigned int meson_mmc_get_timeout_msecs(struct mmc_data *data)
{
        unsigned int timeout = data->timeout_ns / NSEC_PER_MSEC;

        if (!timeout)
                return SD_EMMC_CMD_TIMEOUT_DATA;

        timeout = roundup_pow_of_two(timeout);

        return min(timeout, 32768U); /* max. 2^15 ms */
}

static struct mmc_command *meson_mmc_get_next_command(struct mmc_command *cmd)
{
        if (cmd->opcode == MMC_SET_BLOCK_COUNT && !cmd->error)
                return cmd->mrq->cmd;
        else if (mmc_op_multi(cmd->opcode) &&
                 (!cmd->mrq->sbc || cmd->error || cmd->data->error))
                return cmd->mrq->stop;
        else
                return NULL;
}

static void meson_mmc_get_transfer_mode(struct mmc_host *mmc,
                                        struct mmc_request *mrq)
{
        struct mmc_data *data = mrq->data;
        struct scatterlist *sg;
        int i;
        bool use_desc_chain_mode = true;

        /*
         * Broken SDIO with AP6255-based WiFi on Khadas VIM Pro has been
         * reported. For some strange reason this occurs in descriptor
         * chain mode only. So let's fall back to bounce buffer mode
         * for command SD_IO_RW_EXTENDED.
         */
        if (mrq->cmd->opcode == SD_IO_RW_EXTENDED)
                return;

        for_each_sg(data->sg, sg, data->sg_len, i)
                /* check for 8 byte alignment */
                if (sg->offset & 7) {
                        WARN_ONCE(1, "unaligned scatterlist buffer\n");
                        use_desc_chain_mode = false;
                        break;
                }

        if (use_desc_chain_mode)
                data->host_cookie |= SD_EMMC_DESC_CHAIN_MODE;
}

static inline bool meson_mmc_desc_chain_mode(const struct mmc_data *data)
{
        return data->host_cookie & SD_EMMC_DESC_CHAIN_MODE;
}

static inline bool meson_mmc_bounce_buf_read(const struct mmc_data *data)
{
        return data && data->flags & MMC_DATA_READ &&
               !meson_mmc_desc_chain_mode(data);
}

static void meson_mmc_pre_req(struct mmc_host *mmc, struct mmc_request *mrq)
{
        struct mmc_data *data = mrq->data;

        if (!data)
                return;

        meson_mmc_get_transfer_mode(mmc, mrq);
        data->host_cookie |= SD_EMMC_PRE_REQ_DONE;

        if (!meson_mmc_desc_chain_mode(data))
                return;

        data->sg_count = dma_map_sg(mmc_dev(mmc), data->sg, data->sg_len,
                                   mmc_get_dma_dir(data));
        if (!data->sg_count)
                dev_err(mmc_dev(mmc), "dma_map_sg failed");
}

static void meson_mmc_post_req(struct mmc_host *mmc, struct mmc_request *mrq,
                               int err)
{
        struct mmc_data *data = mrq->data;

        if (data && meson_mmc_desc_chain_mode(data) && data->sg_count)
                dma_unmap_sg(mmc_dev(mmc), data->sg, data->sg_len,
                             mmc_get_dma_dir(data));
}

static bool meson_mmc_timing_is_ddr(struct mmc_ios *ios)
{
        if (ios->timing == MMC_TIMING_MMC_DDR52 ||
            ios->timing == MMC_TIMING_UHS_DDR50 ||
            ios->timing == MMC_TIMING_MMC_HS400)
                return true;

        return false;
}

/*
 * Gating the clock on this controller is tricky.  It seems the mmc clock
 * is also used by the controller.  It may crash during some operation if the
 * clock is stopped.  The safest thing to do, whenever possible, is to keep
 * clock running at stop it at the pad using the pinmux.
 */
static void meson_mmc_clk_gate(struct meson_host *host)
{
        u32 cfg;

        if (host->pins_clk_gate) {
                pinctrl_select_state(host->pinctrl, host->pins_clk_gate);
        } else {
                /*
                 * If the pinmux is not provided - default to the classic and
                 * unsafe method
                 */
                cfg = readl(host->regs + SD_EMMC_CFG);
                cfg |= CFG_STOP_CLOCK;
                writel(cfg, host->regs + SD_EMMC_CFG);
        }
}

static void meson_mmc_clk_ungate(struct meson_host *host)
{
        u32 cfg;

        if (host->pins_clk_gate)
                pinctrl_select_state(host->pinctrl, host->pins_default);

        /* Make sure the clock is not stopped in the controller */
        cfg = readl(host->regs + SD_EMMC_CFG);
        cfg &= ~CFG_STOP_CLOCK;
        writel(cfg, host->regs + SD_EMMC_CFG);
}

static int meson_mmc_clk_set(struct meson_host *host, struct mmc_ios *ios)
{
        struct mmc_host *mmc = host->mmc;
        unsigned long rate = ios->clock;
        int ret;
        u32 cfg;

        /* DDR modes require higher module clock */
        if (meson_mmc_timing_is_ddr(ios))
                rate <<= 1;

        /* Same request - bail-out */
        if (host->req_rate == rate)
                return 0;

        /* stop clock */
        meson_mmc_clk_gate(host);
        host->req_rate = 0;

        if (!rate) {
                mmc->actual_clock = 0;
                /* return with clock being stopped */
                return 0;
        }

        /* Stop the clock during rate change to avoid glitches */
        cfg = readl(host->regs + SD_EMMC_CFG);
        cfg |= CFG_STOP_CLOCK;
        writel(cfg, host->regs + SD_EMMC_CFG);

        ret = clk_set_rate(host->mmc_clk, rate);
        if (ret) {
                dev_err(host->dev, "Unable to set cfg_div_clk to %lu. ret=%d\n",
                        rate, ret);
                return ret;
        }

        host->req_rate = rate;
        mmc->actual_clock = clk_get_rate(host->mmc_clk);

        /* We should report the real output frequency of the controller */
        if (meson_mmc_timing_is_ddr(ios))
                mmc->actual_clock >>= 1;

        dev_dbg(host->dev, "clk rate: %u Hz\n", mmc->actual_clock);
        if (ios->clock != mmc->actual_clock)
                dev_dbg(host->dev, "requested rate was %u\n", ios->clock);

        /* (re)start clock */
        meson_mmc_clk_ungate(host);

        return 0;
}

/*
 * The SD/eMMC IP block has an internal mux and divider used for
 * generating the MMC clock.  Use the clock framework to create and
 * manage these clocks.
 */
static int meson_mmc_clk_init(struct meson_host *host)
{
        struct clk_init_data init;
        struct clk_mux *mux;
        struct clk_divider *div;
        struct meson_mmc_phase *core, *tx, *rx;
        struct clk *clk;
        char clk_name[32];
        int i, ret = 0;
        const char *mux_parent_names[MUX_CLK_NUM_PARENTS];
        const char *clk_parent[1];
        u32 clk_reg;

        /* init SD_EMMC_CLOCK to sane defaults w/min clock rate */
        clk_reg = 0;
        clk_reg |= CLK_ALWAYS_ON(host);
        clk_reg |= CLK_DIV_MASK;
        writel(clk_reg, host->regs + SD_EMMC_CLOCK);

        /* get the mux parents */
        for (i = 0; i < MUX_CLK_NUM_PARENTS; i++) {
                struct clk *clk;
                char name[16];

                snprintf(name, sizeof(name), "clkin%d", i);
                clk = devm_clk_get(host->dev, name);
                if (IS_ERR(clk)) {
                        if (clk != ERR_PTR(-EPROBE_DEFER))
                                dev_err(host->dev, "Missing clock %s\n", name);
                        return PTR_ERR(clk);
                }

                mux_parent_names[i] = __clk_get_name(clk);
        }

        /* create the mux */
        mux = devm_kzalloc(host->dev, sizeof(*mux), GFP_KERNEL);
        if (!mux)
                return -ENOMEM;

        snprintf(clk_name, sizeof(clk_name), "%s#mux", dev_name(host->dev));
        init.name = clk_name;
        init.ops = &clk_mux_ops;
        init.flags = 0;
        init.parent_names = mux_parent_names;
        init.num_parents = MUX_CLK_NUM_PARENTS;

        mux->reg = host->regs + SD_EMMC_CLOCK;
        mux->shift = __ffs(CLK_SRC_MASK);
        mux->mask = CLK_SRC_MASK >> mux->shift;
        mux->hw.init = &init;

        clk = devm_clk_register(host->dev, &mux->hw);
        if (WARN_ON(IS_ERR(clk)))
                return PTR_ERR(clk);

        /* create the divider */
        div = devm_kzalloc(host->dev, sizeof(*div), GFP_KERNEL);
        if (!div)
                return -ENOMEM;

        snprintf(clk_name, sizeof(clk_name), "%s#div", dev_name(host->dev));
        init.name = clk_name;
        init.ops = &clk_divider_ops;
        init.flags = CLK_SET_RATE_PARENT;
        clk_parent[0] = __clk_get_name(clk);
        init.parent_names = clk_parent;
        init.num_parents = 1;

        div->reg = host->regs + SD_EMMC_CLOCK;
        div->shift = __ffs(CLK_DIV_MASK);
        div->width = __builtin_popcountl(CLK_DIV_MASK);
        div->hw.init = &init;
        div->flags = CLK_DIVIDER_ONE_BASED;

        clk = devm_clk_register(host->dev, &div->hw);
        if (WARN_ON(IS_ERR(clk)))
                return PTR_ERR(clk);

        /* create the mmc core clock */
        core = devm_kzalloc(host->dev, sizeof(*core), GFP_KERNEL);
        if (!core)
                return -ENOMEM;

        snprintf(clk_name, sizeof(clk_name), "%s#core", dev_name(host->dev));
        init.name = clk_name;
        init.ops = &meson_mmc_clk_phase_ops;
        init.flags = CLK_SET_RATE_PARENT;
        clk_parent[0] = __clk_get_name(clk);
        init.parent_names = clk_parent;
        init.num_parents = 1;

        core->reg = host->regs + SD_EMMC_CLOCK;
        core->phase_mask = CLK_CORE_PHASE_MASK;
        core->hw.init = &init;

        host->mmc_clk = devm_clk_register(host->dev, &core->hw);
        if (WARN_ON(PTR_ERR_OR_ZERO(host->mmc_clk)))
                return PTR_ERR(host->mmc_clk);

        /* create the mmc tx clock */
        tx = devm_kzalloc(host->dev, sizeof(*tx), GFP_KERNEL);
        if (!tx)
                return -ENOMEM;

        snprintf(clk_name, sizeof(clk_name), "%s#tx", dev_name(host->dev));
        init.name = clk_name;
        init.ops = &meson_mmc_clk_phase_ops;
        init.flags = 0;
        clk_parent[0] = __clk_get_name(host->mmc_clk);
        init.parent_names = clk_parent;
        init.num_parents = 1;

        tx->reg = host->regs + SD_EMMC_CLOCK;
        tx->phase_mask = CLK_TX_PHASE_MASK;
        tx->delay_mask = CLK_TX_DELAY_MASK(host);
        tx->delay_step_ps = CLK_DELAY_STEP_PS;
        tx->hw.init = &init;

        host->tx_clk = devm_clk_register(host->dev, &tx->hw);
        if (WARN_ON(PTR_ERR_OR_ZERO(host->tx_clk)))
                return PTR_ERR(host->tx_clk);

        /* create the mmc rx clock */
        rx = devm_kzalloc(host->dev, sizeof(*rx), GFP_KERNEL);
        if (!rx)
                return -ENOMEM;

        snprintf(clk_name, sizeof(clk_name), "%s#rx", dev_name(host->dev));
        init.name = clk_name;
        init.ops = &meson_mmc_clk_phase_ops;
        init.flags = 0;
        clk_parent[0] = __clk_get_name(host->mmc_clk);
        init.parent_names = clk_parent;
        init.num_parents = 1;

        rx->reg = host->regs + SD_EMMC_CLOCK;
        rx->phase_mask = CLK_RX_PHASE_MASK;
        rx->delay_mask = CLK_RX_DELAY_MASK(host);
        rx->delay_step_ps = CLK_DELAY_STEP_PS;
        rx->hw.init = &init;

        host->rx_clk = devm_clk_register(host->dev, &rx->hw);
        if (WARN_ON(PTR_ERR_OR_ZERO(host->rx_clk)))
                return PTR_ERR(host->rx_clk);

        /* init SD_EMMC_CLOCK to sane defaults w/min clock rate */
        host->mmc->f_min = clk_round_rate(host->mmc_clk, 400000);
        ret = clk_set_rate(host->mmc_clk, host->mmc->f_min);
        if (ret)
                return ret;

        clk_set_phase(host->mmc_clk, 180);
        clk_set_phase(host->tx_clk, 0);
        clk_set_phase(host->rx_clk, 0);

        return clk_prepare_enable(host->mmc_clk);
}

static void meson_mmc_shift_map(unsigned long *map, unsigned long shift)
{
        DECLARE_BITMAP(left, CLK_PHASE_POINT_NUM);
        DECLARE_BITMAP(right, CLK_PHASE_POINT_NUM);

        /*
         * shift the bitmap right and reintroduce the dropped bits on the left
         * of the bitmap
         */
        bitmap_shift_right(right, map, shift, CLK_PHASE_POINT_NUM);
        bitmap_shift_left(left, map, CLK_PHASE_POINT_NUM - shift,
                          CLK_PHASE_POINT_NUM);
        bitmap_or(map, left, right, CLK_PHASE_POINT_NUM);
}

static void meson_mmc_find_next_region(unsigned long *map,
                                       unsigned long *start,
                                       unsigned long *stop)
{
        *start = find_next_bit(map, CLK_PHASE_POINT_NUM, *start);
        *stop = find_next_zero_bit(map, CLK_PHASE_POINT_NUM, *start);
}

static int meson_mmc_find_tuning_point(unsigned long *test)
{
        unsigned long shift, stop, offset = 0, start = 0, size = 0;

        /* Get the all good/all bad situation out the way */
        if (bitmap_full(test, CLK_PHASE_POINT_NUM))
                return 0; /* All points are good so point 0 will do */
        else if (bitmap_empty(test, CLK_PHASE_POINT_NUM))
                return -EIO; /* No successful tuning point */

        /*
         * Now we know there is a least one region find. Make sure it does
         * not wrap by the shifting the bitmap if necessary
         */
        shift = find_first_zero_bit(test, CLK_PHASE_POINT_NUM);
        if (shift != 0)
                meson_mmc_shift_map(test, shift);

        while (start < CLK_PHASE_POINT_NUM) {
                meson_mmc_find_next_region(test, &start, &stop);

                if ((stop - start) > size) {
                        offset = start;
                        size = stop - start;
                }

                start = stop;
        }

        /* Get the center point of the region */
        offset += (size / 2);

        /* Shift the result back */
        offset = (offset + shift) % CLK_PHASE_POINT_NUM;

        return offset;
}

static int meson_mmc_clk_phase_tuning(struct mmc_host *mmc, u32 opcode,
                                      struct clk *clk)
{
        int point, ret;
        DECLARE_BITMAP(test, CLK_PHASE_POINT_NUM);

        dev_dbg(mmc_dev(mmc), "%s phase/delay tunning...\n",
                __clk_get_name(clk));
        bitmap_zero(test, CLK_PHASE_POINT_NUM);

        /* Explore tuning points */
        for (point = 0; point < CLK_PHASE_POINT_NUM; point++) {
                clk_set_phase(clk, point * CLK_PHASE_STEP);
                ret = mmc_send_tuning(mmc, opcode, NULL);
                if (!ret)
                        set_bit(point, test);
        }

        /* Find the optimal tuning point and apply it */
        point = meson_mmc_find_tuning_point(test);
        if (point < 0)
                return point; /* tuning failed */

        clk_set_phase(clk, point * CLK_PHASE_STEP);
        dev_dbg(mmc_dev(mmc), "success with phase: %d\n",
                clk_get_phase(clk));
        return 0;
}

static int meson_mmc_execute_tuning(struct mmc_host *mmc, u32 opcode)
{
        struct meson_host *host = mmc_priv(mmc);
        int adj = 0;

        /* enable signal resampling w/o delay */
        adj = ADJUST_ADJ_EN;
        writel(adj, host->regs + host->data->adjust);

        return meson_mmc_clk_phase_tuning(mmc, opcode, host->rx_clk);
}

static void meson_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
{
        struct meson_host *host = mmc_priv(mmc);
        u32 bus_width, val;
        int err;

        /*
         * GPIO regulator, only controls switching between 1v8 and
         * 3v3, doesn't support MMC_POWER_OFF, MMC_POWER_ON.
         */
        switch (ios->power_mode) {
        case MMC_POWER_OFF:
                if (!IS_ERR(mmc->supply.vmmc))
                        mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, 0);

                if (!IS_ERR(mmc->supply.vqmmc) && host->vqmmc_enabled) {
                        regulator_disable(mmc->supply.vqmmc);
                        host->vqmmc_enabled = false;
                }

                break;

        case MMC_POWER_UP:
                if (!IS_ERR(mmc->supply.vmmc))
                        mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, ios->vdd);

                /* disable signal resampling */
                writel(0, host->regs + host->data->adjust);

                /* Reset rx phase */
                clk_set_phase(host->rx_clk, 0);

                break;

        case MMC_POWER_ON:
                if (!IS_ERR(mmc->supply.vqmmc) && !host->vqmmc_enabled) {
                        int ret = regulator_enable(mmc->supply.vqmmc);

                        if (ret < 0)
                                dev_err(host->dev,
                                        "failed to enable vqmmc regulator\n");
                        else
                                host->vqmmc_enabled = true;
                }

                break;
        }

        /* Bus width */
        switch (ios->bus_width) {
        case MMC_BUS_WIDTH_1:
                bus_width = CFG_BUS_WIDTH_1;
                break;
        case MMC_BUS_WIDTH_4:
                bus_width = CFG_BUS_WIDTH_4;
                break;
        case MMC_BUS_WIDTH_8:
                bus_width = CFG_BUS_WIDTH_8;
                break;
        default:
                dev_err(host->dev, "Invalid ios->bus_width: %u.  Setting to 4.\n",
                        ios->bus_width);
                bus_width = CFG_BUS_WIDTH_4;
        }

        val = readl(host->regs + SD_EMMC_CFG);
        val &= ~CFG_BUS_WIDTH_MASK;
        val |= FIELD_PREP(CFG_BUS_WIDTH_MASK, bus_width);

        val &= ~CFG_DDR;
        if (meson_mmc_timing_is_ddr(ios))
                val |= CFG_DDR;

        val &= ~CFG_CHK_DS;
        if (ios->timing == MMC_TIMING_MMC_HS400)
                val |= CFG_CHK_DS;

        err = meson_mmc_clk_set(host, ios);
        if (err)
                dev_err(host->dev, "Failed to set clock: %d\n,", err);

        writel(val, host->regs + SD_EMMC_CFG);
        dev_dbg(host->dev, "SD_EMMC_CFG:  0x%08x\n", val);
}

static void meson_mmc_request_done(struct mmc_host *mmc,
                                   struct mmc_request *mrq)
{
        struct meson_host *host = mmc_priv(mmc);

        host->cmd = NULL;
        mmc_request_done(host->mmc, mrq);
}

static void meson_mmc_set_blksz(struct mmc_host *mmc, unsigned int blksz)
{
        struct meson_host *host = mmc_priv(mmc);
        u32 cfg, blksz_old;

        cfg = readl(host->regs + SD_EMMC_CFG);
        blksz_old = FIELD_GET(CFG_BLK_LEN_MASK, cfg);

        if (!is_power_of_2(blksz))
                dev_err(host->dev, "blksz %u is not a power of 2\n", blksz);

        blksz = ilog2(blksz);

        /* check if block-size matches, if not update */
        if (blksz == blksz_old)
                return;

        dev_dbg(host->dev, "%s: update blk_len %d -> %d\n", __func__,
                blksz_old, blksz);

        cfg &= ~CFG_BLK_LEN_MASK;
        cfg |= FIELD_PREP(CFG_BLK_LEN_MASK, blksz);
        writel(cfg, host->regs + SD_EMMC_CFG);
}

static void meson_mmc_set_response_bits(struct mmc_command *cmd, u32 *cmd_cfg)
{
        if (cmd->flags & MMC_RSP_PRESENT) {
                if (cmd->flags & MMC_RSP_136)
                        *cmd_cfg |= CMD_CFG_RESP_128;
                *cmd_cfg |= CMD_CFG_RESP_NUM;

                if (!(cmd->flags & MMC_RSP_CRC))
                        *cmd_cfg |= CMD_CFG_RESP_NOCRC;

                if (cmd->flags & MMC_RSP_BUSY)
                        *cmd_cfg |= CMD_CFG_R1B;
        } else {
                *cmd_cfg |= CMD_CFG_NO_RESP;
        }
}

static void meson_mmc_desc_chain_transfer(struct mmc_host *mmc, u32 cmd_cfg)
{
        struct meson_host *host = mmc_priv(mmc);
        struct sd_emmc_desc *desc = host->descs;
        struct mmc_data *data = host->cmd->data;
        struct scatterlist *sg;
        u32 start;
        int i;

        if (data->flags & MMC_DATA_WRITE)
                cmd_cfg |= CMD_CFG_DATA_WR;

        if (data->blocks > 1) {
                cmd_cfg |= CMD_CFG_BLOCK_MODE;
                meson_mmc_set_blksz(mmc, data->blksz);
        }

        for_each_sg(data->sg, sg, data->sg_count, i) {
                unsigned int len = sg_dma_len(sg);

                if (data->blocks > 1)
                        len /= data->blksz;

                desc[i].cmd_cfg = cmd_cfg;
                desc[i].cmd_cfg |= FIELD_PREP(CMD_CFG_LENGTH_MASK, len);
                if (i > 0)
                        desc[i].cmd_cfg |= CMD_CFG_NO_CMD;
                desc[i].cmd_arg = host->cmd->arg;
                desc[i].cmd_resp = 0;
                desc[i].cmd_data = sg_dma_address(sg);
        }
        desc[data->sg_count - 1].cmd_cfg |= CMD_CFG_END_OF_CHAIN;

        dma_wmb(); /* ensure descriptor is written before kicked */
        start = host->descs_dma_addr | START_DESC_BUSY;
        writel(start, host->regs + SD_EMMC_START);
}

static void meson_mmc_start_cmd(struct mmc_host *mmc, struct mmc_command *cmd)
{
        struct meson_host *host = mmc_priv(mmc);
        struct mmc_data *data = cmd->data;
        u32 cmd_cfg = 0, cmd_data = 0;
        unsigned int xfer_bytes = 0;

        /* Setup descriptors */
        dma_rmb();

        host->cmd = cmd;

        cmd_cfg |= FIELD_PREP(CMD_CFG_CMD_INDEX_MASK, cmd->opcode);
        cmd_cfg |= CMD_CFG_OWNER;  /* owned by CPU */
        cmd_cfg |= CMD_CFG_ERROR; /* stop in case of error */

        meson_mmc_set_response_bits(cmd, &cmd_cfg);

        /* data? */
        if (data) {
                data->bytes_xfered = 0;
                cmd_cfg |= CMD_CFG_DATA_IO;
                cmd_cfg |= FIELD_PREP(CMD_CFG_TIMEOUT_MASK,
                                      ilog2(meson_mmc_get_timeout_msecs(data)));

                if (meson_mmc_desc_chain_mode(data)) {
                        meson_mmc_desc_chain_transfer(mmc, cmd_cfg);
                        return;
                }

                if (data->blocks > 1) {
                        cmd_cfg |= CMD_CFG_BLOCK_MODE;
                        cmd_cfg |= FIELD_PREP(CMD_CFG_LENGTH_MASK,
                                              data->blocks);
                        meson_mmc_set_blksz(mmc, data->blksz);
                } else {
                        cmd_cfg |= FIELD_PREP(CMD_CFG_LENGTH_MASK, data->blksz);
                }

                xfer_bytes = data->blksz * data->blocks;
                if (data->flags & MMC_DATA_WRITE) {
                        cmd_cfg |= CMD_CFG_DATA_WR;
                        WARN_ON(xfer_bytes > host->bounce_buf_size);
                        sg_copy_to_buffer(data->sg, data->sg_len,
                                          host->bounce_buf, xfer_bytes);
                        dma_wmb();
                }

                cmd_data = host->bounce_dma_addr & CMD_DATA_MASK;
        } else {
                cmd_cfg |= FIELD_PREP(CMD_CFG_TIMEOUT_MASK,
                                      ilog2(SD_EMMC_CMD_TIMEOUT));
        }

        /* Last descriptor */
        cmd_cfg |= CMD_CFG_END_OF_CHAIN;
        writel(cmd_cfg, host->regs + SD_EMMC_CMD_CFG);
        writel(cmd_data, host->regs + SD_EMMC_CMD_DAT);
        writel(0, host->regs + SD_EMMC_CMD_RSP);
        wmb(); /* ensure descriptor is written before kicked */
        writel(cmd->arg, host->regs + SD_EMMC_CMD_ARG);
}

static void meson_mmc_request(struct mmc_host *mmc, struct mmc_request *mrq)
{
        struct meson_host *host = mmc_priv(mmc);
        bool needs_pre_post_req = mrq->data &&
                        !(mrq->data->host_cookie & SD_EMMC_PRE_REQ_DONE);

        if (needs_pre_post_req) {
                meson_mmc_get_transfer_mode(mmc, mrq);
                if (!meson_mmc_desc_chain_mode(mrq->data))
                        needs_pre_post_req = false;
        }

        if (needs_pre_post_req)
                meson_mmc_pre_req(mmc, mrq);

        /* Stop execution */
        writel(0, host->regs + SD_EMMC_START);

        meson_mmc_start_cmd(mmc, mrq->sbc ?: mrq->cmd);

        if (needs_pre_post_req)
                meson_mmc_post_req(mmc, mrq, 0);
}

static void meson_mmc_read_resp(struct mmc_host *mmc, struct mmc_command *cmd)
{
        struct meson_host *host = mmc_priv(mmc);

        if (cmd->flags & MMC_RSP_136) {
                cmd->resp[0] = readl(host->regs + SD_EMMC_CMD_RSP3);
                cmd->resp[1] = readl(host->regs + SD_EMMC_CMD_RSP2);
                cmd->resp[2] = readl(host->regs + SD_EMMC_CMD_RSP1);
                cmd->resp[3] = readl(host->regs + SD_EMMC_CMD_RSP);
        } else if (cmd->flags & MMC_RSP_PRESENT) {
                cmd->resp[0] = readl(host->regs + SD_EMMC_CMD_RSP);
        }
}

static irqreturn_t meson_mmc_irq(int irq, void *dev_id)
{
        struct meson_host *host = dev_id;
        struct mmc_command *cmd;
        struct mmc_data *data;
        u32 irq_en, status, raw_status;
        irqreturn_t ret = IRQ_NONE;

        irq_en = readl(host->regs + SD_EMMC_IRQ_EN);
        raw_status = readl(host->regs + SD_EMMC_STATUS);
        status = raw_status & irq_en;

        if (!status) {
                dev_dbg(host->dev,
                        "Unexpected IRQ! irq_en 0x%08x - status 0x%08x\n",
                         irq_en, raw_status);
                return IRQ_NONE;
        }

        if (WARN_ON(!host) || WARN_ON(!host->cmd))
                return IRQ_NONE;

        cmd = host->cmd;
        data = cmd->data;
        cmd->error = 0;
        if (status & IRQ_CRC_ERR) {
                dev_dbg(host->dev, "CRC Error - status 0x%08x\n", status);
                cmd->error = -EILSEQ;
                ret = IRQ_WAKE_THREAD;
                goto out;
        }

        if (status & IRQ_TIMEOUTS) {
                dev_dbg(host->dev, "Timeout - status 0x%08x\n", status);
                cmd->error = -ETIMEDOUT;
                ret = IRQ_WAKE_THREAD;
                goto out;
        }

        meson_mmc_read_resp(host->mmc, cmd);

        if (status & IRQ_SDIO) {
                dev_dbg(host->dev, "IRQ: SDIO TODO.\n");
                ret = IRQ_HANDLED;
        }

        if (status & (IRQ_END_OF_CHAIN | IRQ_RESP_STATUS)) {
                if (data && !cmd->error)
                        data->bytes_xfered = data->blksz * data->blocks;
                if (meson_mmc_bounce_buf_read(data) ||
                    meson_mmc_get_next_command(cmd))
                        ret = IRQ_WAKE_THREAD;
                else
                        ret = IRQ_HANDLED;
        }

out:
        /* ack all enabled interrupts */
        writel(irq_en, host->regs + SD_EMMC_STATUS);

        if (cmd->error) {
                /* Stop desc in case of errors */
                u32 start = readl(host->regs + SD_EMMC_START);

                start &= ~START_DESC_BUSY;
                writel(start, host->regs + SD_EMMC_START);
        }

        if (ret == IRQ_HANDLED)
                meson_mmc_request_done(host->mmc, cmd->mrq);

        return ret;
}

static int meson_mmc_wait_desc_stop(struct meson_host *host)
{
        int loop;
        u32 status;

        /*
         * It may sometimes take a while for it to actually halt. Here, we
         * are giving it 5ms to comply
         *
         * If we don't confirm the descriptor is stopped, it might raise new
         * IRQs after we have called mmc_request_done() which is bad.
         */
        for (loop = 50; loop; loop--) {
                status = readl(host->regs + SD_EMMC_STATUS);
                if (status & (STATUS_BUSY | STATUS_DESC_BUSY))
                        udelay(100);
                else
                        break;
        }

        if (status & (STATUS_BUSY | STATUS_DESC_BUSY)) {
                dev_err(host->dev, "Timed out waiting for host to stop\n");
                return -ETIMEDOUT;
        }

        return 0;
}

static irqreturn_t meson_mmc_irq_thread(int irq, void *dev_id)
{
        struct meson_host *host = dev_id;
        struct mmc_command *next_cmd, *cmd = host->cmd;
        struct mmc_data *data;
        unsigned int xfer_bytes;

        if (WARN_ON(!cmd))
                return IRQ_NONE;

        if (cmd->error) {
                meson_mmc_wait_desc_stop(host);
                meson_mmc_request_done(host->mmc, cmd->mrq);

                return IRQ_HANDLED;
        }

        data = cmd->data;
        if (meson_mmc_bounce_buf_read(data)) {
                xfer_bytes = data->blksz * data->blocks;
                WARN_ON(xfer_bytes > host->bounce_buf_size);
                sg_copy_from_buffer(data->sg, data->sg_len,
                                    host->bounce_buf, xfer_bytes);
        }

        next_cmd = meson_mmc_get_next_command(cmd);
        if (next_cmd)
                meson_mmc_start_cmd(host->mmc, next_cmd);
        else
                meson_mmc_request_done(host->mmc, cmd->mrq);

        return IRQ_HANDLED;
}

/*
 * NOTE: we only need this until the GPIO/pinctrl driver can handle
 * interrupts.  For now, the MMC core will use this for polling.
 */
static int meson_mmc_get_cd(struct mmc_host *mmc)
{
        int status = mmc_gpio_get_cd(mmc);

        if (status == -ENOSYS)
                return 1; /* assume present */

        return status;
}

static void meson_mmc_cfg_init(struct meson_host *host)
{
        u32 cfg = 0;

        cfg |= FIELD_PREP(CFG_RESP_TIMEOUT_MASK,
                          ilog2(SD_EMMC_CFG_RESP_TIMEOUT));
        cfg |= FIELD_PREP(CFG_RC_CC_MASK, ilog2(SD_EMMC_CFG_CMD_GAP));
        cfg |= FIELD_PREP(CFG_BLK_LEN_MASK, ilog2(SD_EMMC_CFG_BLK_SIZE));

        /* abort chain on R/W errors */
        cfg |= CFG_ERR_ABORT;

        writel(cfg, host->regs + SD_EMMC_CFG);
}

static int meson_mmc_card_busy(struct mmc_host *mmc)
{
        struct meson_host *host = mmc_priv(mmc);
        u32 regval;

        regval = readl(host->regs + SD_EMMC_STATUS);

        /* We are only interrested in lines 0 to 3, so mask the other ones */
        return !(FIELD_GET(STATUS_DATI, regval) & 0xf);
}

static int meson_mmc_voltage_switch(struct mmc_host *mmc, struct mmc_ios *ios)
{
        /* vqmmc regulator is available */
        if (!IS_ERR(mmc->supply.vqmmc)) {
                /*
                 * The usual amlogic setup uses a GPIO to switch from one
                 * regulator to the other. While the voltage ramp up is
                 * pretty fast, care must be taken when switching from 3.3v
                 * to 1.8v. Please make sure the regulator framework is aware
                 * of your own regulator constraints
                 */
                return mmc_regulator_set_vqmmc(mmc, ios);
        }

        /* no vqmmc regulator, assume fixed regulator at 3/3.3V */
        if (ios->signal_voltage == MMC_SIGNAL_VOLTAGE_330)
                return 0;

        return -EINVAL;
}

static const struct mmc_host_ops meson_mmc_ops = {
        .request        = meson_mmc_request,
        .set_ios        = meson_mmc_set_ios,
        .get_cd         = meson_mmc_get_cd,
        .pre_req        = meson_mmc_pre_req,
        .post_req       = meson_mmc_post_req,
        .execute_tuning = meson_mmc_execute_tuning,
        .card_busy      = meson_mmc_card_busy,
        .start_signal_voltage_switch = meson_mmc_voltage_switch,
};

static int meson_mmc_probe(struct platform_device *pdev)
{
        struct resource *res;
        struct meson_host *host;
        struct mmc_host *mmc;
        int ret;

        mmc = mmc_alloc_host(sizeof(struct meson_host), &pdev->dev);
        if (!mmc)
                return -ENOMEM;
        host = mmc_priv(mmc);
        host->mmc = mmc;
        host->dev = &pdev->dev;
        dev_set_drvdata(&pdev->dev, host);

        /* Get regulators and the supported OCR mask */
        host->vqmmc_enabled = false;
        ret = mmc_regulator_get_supply(mmc);
        if (ret)
                goto free_host;

        ret = mmc_of_parse(mmc);
        if (ret) {
                if (ret != -EPROBE_DEFER)
                        dev_warn(&pdev->dev, "error parsing DT: %d\n", ret);
                goto free_host;
        }

        host->data = (struct meson_mmc_data *)
                of_device_get_match_data(&pdev->dev);
        if (!host->data) {
                ret = -EINVAL;
                goto free_host;
        }

        ret = device_reset_optional(&pdev->dev);
        if (ret) {
                if (ret != -EPROBE_DEFER)
                        dev_err(&pdev->dev, "device reset failed: %d\n", ret);

                return ret;
        }

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        host->regs = devm_ioremap_resource(&pdev->dev, res);
        if (IS_ERR(host->regs)) {
                ret = PTR_ERR(host->regs);
                goto free_host;
        }

        host->irq = platform_get_irq(pdev, 0);
        if (host->irq <= 0) {
                dev_err(&pdev->dev, "failed to get interrupt resource.\n");
                ret = -EINVAL;
                goto free_host;
        }

        host->pinctrl = devm_pinctrl_get(&pdev->dev);
        if (IS_ERR(host->pinctrl)) {
                ret = PTR_ERR(host->pinctrl);
                goto free_host;
        }

        host->pins_default = pinctrl_lookup_state(host->pinctrl,
                                                  PINCTRL_STATE_DEFAULT);
        if (IS_ERR(host->pins_default)) {
                ret = PTR_ERR(host->pins_default);
                goto free_host;
        }

        host->pins_clk_gate = pinctrl_lookup_state(host->pinctrl,
                                                   "clk-gate");
        if (IS_ERR(host->pins_clk_gate)) {
                dev_warn(&pdev->dev,
                         "can't get clk-gate pinctrl, using clk_stop bit\n");
                host->pins_clk_gate = NULL;
        }

        host->core_clk = devm_clk_get(&pdev->dev, "core");
        if (IS_ERR(host->core_clk)) {
                ret = PTR_ERR(host->core_clk);
                goto free_host;
        }

        ret = clk_prepare_enable(host->core_clk);
        if (ret)
                goto free_host;

        ret = meson_mmc_clk_init(host);
        if (ret)
                goto err_core_clk;

        /* set config to sane default */
        meson_mmc_cfg_init(host);

        /* Stop execution */
        writel(0, host->regs + SD_EMMC_START);

        /* clear, ack and enable interrupts */
        writel(0, host->regs + SD_EMMC_IRQ_EN);
        writel(IRQ_CRC_ERR | IRQ_TIMEOUTS | IRQ_END_OF_CHAIN,
               host->regs + SD_EMMC_STATUS);
        writel(IRQ_CRC_ERR | IRQ_TIMEOUTS | IRQ_END_OF_CHAIN,
               host->regs + SD_EMMC_IRQ_EN);

        ret = request_threaded_irq(host->irq, meson_mmc_irq,
                        meson_mmc_irq_thread, IRQF_SHARED, NULL, host);
        if (ret)
                goto err_init_clk;

        mmc->caps |= MMC_CAP_CMD23;
        mmc->max_blk_count = CMD_CFG_LENGTH_MASK;
        mmc->max_req_size = mmc->max_blk_count * mmc->max_blk_size;
        mmc->max_segs = SD_EMMC_DESC_BUF_LEN / sizeof(struct sd_emmc_desc);
        mmc->max_seg_size = mmc->max_req_size;

        /* data bounce buffer */
        host->bounce_buf_size = mmc->max_req_size;
        host->bounce_buf =
                dma_alloc_coherent(host->dev, host->bounce_buf_size,
                                   &host->bounce_dma_addr, GFP_KERNEL);
        if (host->bounce_buf == NULL) {
                dev_err(host->dev, "Unable to map allocate DMA bounce buffer.\n");
                ret = -ENOMEM;
                goto err_free_irq;
        }

        host->descs = dma_alloc_coherent(host->dev, SD_EMMC_DESC_BUF_LEN,
                      &host->descs_dma_addr, GFP_KERNEL);
        if (!host->descs) {
                dev_err(host->dev, "Allocating descriptor DMA buffer failed\n");
                ret = -ENOMEM;
                goto err_bounce_buf;
        }

        mmc->ops = &meson_mmc_ops;
        mmc_add_host(mmc);

        return 0;

err_bounce_buf:
        dma_free_coherent(host->dev, host->bounce_buf_size,
                          host->bounce_buf, host->bounce_dma_addr);
err_free_irq:
        free_irq(host->irq, host);
err_init_clk:
        clk_disable_unprepare(host->mmc_clk);
err_core_clk:
        clk_disable_unprepare(host->core_clk);
free_host:
        mmc_free_host(mmc);
        return ret;
}

static int meson_mmc_remove(struct platform_device *pdev)
{
        struct meson_host *host = dev_get_drvdata(&pdev->dev);

        mmc_remove_host(host->mmc);

        /* disable interrupts */
        writel(0, host->regs + SD_EMMC_IRQ_EN);
        free_irq(host->irq, host);

        dma_free_coherent(host->dev, SD_EMMC_DESC_BUF_LEN,
                          host->descs, host->descs_dma_addr);
        dma_free_coherent(host->dev, host->bounce_buf_size,
                          host->bounce_buf, host->bounce_dma_addr);

        clk_disable_unprepare(host->mmc_clk);
        clk_disable_unprepare(host->core_clk);

        mmc_free_host(host->mmc);
        return 0;
}

static const struct meson_mmc_data meson_gx_data = {
        .tx_delay_mask  = CLK_V2_TX_DELAY_MASK,
        .rx_delay_mask  = CLK_V2_RX_DELAY_MASK,
        .always_on      = CLK_V2_ALWAYS_ON,
        .adjust         = SD_EMMC_ADJUST,
};

static const struct meson_mmc_data meson_axg_data = {
        .tx_delay_mask  = CLK_V3_TX_DELAY_MASK,
        .rx_delay_mask  = CLK_V3_RX_DELAY_MASK,
        .always_on      = CLK_V3_ALWAYS_ON,
        .adjust         = SD_EMMC_V3_ADJUST,
};

static const struct of_device_id meson_mmc_of_match[] = {
        { .compatible = "amlogic,meson-gx-mmc",         .data = &meson_gx_data },
        { .compatible = "amlogic,meson-gxbb-mmc",       .data = &meson_gx_data },
        { .compatible = "amlogic,meson-gxl-mmc",        .data = &meson_gx_data },
        { .compatible = "amlogic,meson-gxm-mmc",        .data = &meson_gx_data },
        { .compatible = "amlogic,meson-axg-mmc",        .data = &meson_axg_data },
        {}
};
MODULE_DEVICE_TABLE(of, meson_mmc_of_match);

static struct platform_driver meson_mmc_driver = {
        .probe          = meson_mmc_probe,
        .remove         = meson_mmc_remove,
        .driver         = {
                .name = DRIVER_NAME,
                .of_match_table = of_match_ptr(meson_mmc_of_match),
        },
};

module_platform_driver(meson_mmc_driver);

MODULE_DESCRIPTION("Amlogic S905*/GX*/AXG SD/eMMC driver");
MODULE_AUTHOR("Kevin Hilman <khilman@baylibre.com>");
MODULE_LICENSE("GPL v2");