root/drivers/mmc/host/sunplus-mmc.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) Sunplus Inc.
 * Author: Tony Huang <tonyhuang.sunplus@gmail.com>
 * Author: Li-hao Kuo <lhjeff911@gmail.com>
 */

#include <linux/bitfield.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/interrupt.h>
#include <linux/iopoll.h>
#include <linux/mmc/core.h>
#include <linux/mmc/host.h>
#include <linux/mmc/mmc.h>
#include <linux/mmc/sdio.h>
#include <linux/mmc/slot-gpio.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm.h>
#include <linux/pm_runtime.h>
#include <linux/reset.h>

#define SPMMC_MIN_CLK                   400000
#define SPMMC_MAX_CLK                   52000000
#define SPMMC_MAX_BLK_COUNT             65536
#define SPMMC_MAX_TUNABLE_DLY   7
#define SPMMC_TIMEOUT_US                500000
#define SPMMC_POLL_DELAY_US             10

#define SPMMC_CARD_MEDIATYPE_SRCDST_REG 0x0000
#define SPMMC_MEDIA_TYPE                GENMASK(2, 0)
#define SPMMC_DMA_SOURCE                GENMASK(6, 4)
#define SPMMC_DMA_DESTINATION           GENMASK(10, 8)
#define SPMMC_MEDIA_NONE        0
#define SPMMC_MEDIA_SD          6
#define SPMMC_MEDIA_MS          7

#define SPMMC_SDRAM_SECTOR_0_SIZE_REG   0x0008
#define SPMMC_DMA_BASE_ADDR_REG         0x000C
#define SPMMC_HW_DMA_CTRL_REG           0x0010
#define SPMMC_HW_DMA_RST        BIT(9)
#define SPMMC_DMAIDLE           BIT(10)

#define SPMMC_MAX_DMA_MEMORY_SECTORS    8

#define SPMMC_SDRAM_SECTOR_1_ADDR_REG 0x0018
#define SPMMC_SDRAM_SECTOR_1_LENG_REG 0x001C
#define SPMMC_SDRAM_SECTOR_2_ADDR_REG 0x0020
#define SPMMC_SDRAM_SECTOR_2_LENG_REG 0x0024
#define SPMMC_SDRAM_SECTOR_3_ADDR_REG 0x0028
#define SPMMC_SDRAM_SECTOR_3_LENG_REG 0x002C
#define SPMMC_SDRAM_SECTOR_4_ADDR_REG 0x0030
#define SPMMC_SDRAM_SECTOR_4_LENG_REG 0x0034
#define SPMMC_SDRAM_SECTOR_5_ADDR_REG 0x0038
#define SPMMC_SDRAM_SECTOR_5_LENG_REG 0x003C
#define SPMMC_SDRAM_SECTOR_6_ADDR_REG 0x0040
#define SPMMC_SDRAM_SECTOR_6_LENG_REG 0x0044
#define SPMMC_SDRAM_SECTOR_7_ADDR_REG 0x0048
#define SPMMC_SDRAM_SECTOR_7_LENG_REG 0x004C

#define SPMMC_SD_INT_REG        0x0088
#define SPMMC_SDINT_SDCMPEN     BIT(0)
#define SPMMC_SDINT_SDCMP       BIT(1)
#define SPMMC_SDINT_SDCMPCLR    BIT(2)
#define SPMMC_SDINT_SDIOEN      BIT(3)
#define SPMMC_SDINT_SDIO        BIT(4)
#define SPMMC_SDINT_SDIOCLR     BIT(5)

#define SPMMC_SD_PAGE_NUM_REG   0x008C

#define SPMMC_SD_CONFIG0_REG    0x0090
#define SPMMC_SD_PIO_MODE       BIT(0)
#define SPMMC_SD_DDR_MODE       BIT(1)
#define SPMMC_SD_LEN_MODE       BIT(2)
#define SPMMC_SD_TRANS_MODE     GENMASK(5, 4)
#define SPMMC_SD_AUTO_RESPONSE  BIT(6)
#define SPMMC_SD_CMD_DUMMY      BIT(7)
#define SPMMC_SD_RSP_CHK_EN     BIT(8)
#define SPMMC_SDIO_MODE         BIT(9)
#define SPMMC_SD_MMC_MODE       BIT(10)
#define SPMMC_SD_DATA_WD        BIT(11)
#define SPMMC_RX4_EN            BIT(14)
#define SPMMC_SD_RSP_TYPE       BIT(15)
#define SPMMC_MMC8_EN           BIT(18)
#define SPMMC_CLOCK_DIVISION    GENMASK(31, 20)

#define SPMMC_SDIO_CTRL_REG             0x0094
#define SPMMC_INT_MULTI_TRIG            BIT(6)

#define SPMMC_SD_RST_REG                0x0098
#define SPMMC_SD_CTRL_REG               0x009C
#define SPMMC_NEW_COMMAND_TRIGGER       BIT(0)
#define SPMMC_DUMMY_CLOCK_TRIGGER       BIT(1)

#define SPMMC_SD_STATUS_REG                                             0x00A0
#define SPMMC_SDSTATUS_DUMMY_READY                              BIT(0)
#define SPMMC_SDSTATUS_RSP_BUF_FULL                             BIT(1)
#define SPMMC_SDSTATUS_TX_DATA_BUF_EMPTY                BIT(2)
#define SPMMC_SDSTATUS_RX_DATA_BUF_FULL                 BIT(3)
#define SPMMC_SDSTATUS_CMD_PIN_STATUS                   BIT(4)
#define SPMMC_SDSTATUS_DAT0_PIN_STATUS                  BIT(5)
#define SPMMC_SDSTATUS_RSP_TIMEOUT                              BIT(6)
#define SPMMC_SDSTATUS_CARD_CRC_CHECK_TIMEOUT   BIT(7)
#define SPMMC_SDSTATUS_STB_TIMEOUT                              BIT(8)
#define SPMMC_SDSTATUS_RSP_CRC7_ERROR                   BIT(9)
#define SPMMC_SDSTATUS_CRC_TOKEN_CHECK_ERROR    BIT(10)
#define SPMMC_SDSTATUS_RDATA_CRC16_ERROR                BIT(11)
#define SPMMC_SDSTATUS_SUSPEND_STATE_READY              BIT(12)
#define SPMMC_SDSTATUS_BUSY_CYCLE                               BIT(13)
#define SPMMC_SDSTATUS_DAT1_PIN_STATUS                  BIT(14)
#define SPMMC_SDSTATUS_SD_SENSE_STATUS                  BIT(15)
#define SPMMC_SDSTATUS_BOOT_ACK_TIMEOUT                 BIT(16)
#define SPMMC_SDSTATUS_BOOT_DATA_TIMEOUT                BIT(17)
#define SPMMC_SDSTATUS_BOOT_ACK_ERROR                   BIT(18)

#define SPMMC_SD_STATE_REG              0x00A4
#define SPMMC_CRCTOKEN_CHECK_RESULT     GENMASK(6, 4)
#define SPMMC_SDSTATE_ERROR             BIT(13)
#define SPMMC_SDSTATE_FINISH    BIT(14)

#define SPMMC_SD_HW_STATE_REG           0x00A8
#define SPMMC_SD_BLOCKSIZE_REG          0x00AC

#define SPMMC_SD_CONFIG1_REG            0x00B0
#define SPMMC_TX_DUMMY_NUM              GENMASK(8, 0)
#define SPMMC_SD_HIGH_SPEED_EN          BIT(31)

#define SPMMC_SD_TIMING_CONFIG0_REG 0x00B4
#define SPMMC_SD_CLOCK_DELAY    GENMASK(2, 0)
#define SPMMC_SD_WRITE_DATA_DELAY       GENMASK(6, 4)
#define SPMMC_SD_WRITE_COMMAND_DELAY    GENMASK(10, 8)
#define SPMMC_SD_READ_RESPONSE_DELAY    GENMASK(14, 12)
#define SPMMC_SD_READ_DATA_DELAY        GENMASK(18, 16)
#define SPMMC_SD_READ_CRC_DELAY GENMASK(22, 20)

#define SPMMC_SD_PIODATATX_REG          0x00BC
#define SPMMC_SD_PIODATARX_REG          0x00C0
#define SPMMC_SD_CMDBUF0_3_REG          0x00C4
#define SPMMC_SD_CMDBUF4_REG            0x00C8
#define SPMMC_SD_RSPBUF0_3_REG          0x00CC
#define SPMMC_SD_RSPBUF4_5_REG          0x00D0

#define SPMMC_MAX_RETRIES (8 * 8)

struct spmmc_tuning_info {
        int enable_tuning;
        int need_tuning;
        int retried; /* how many times has been retried */
        u32 rd_crc_dly:3;
        u32 rd_dat_dly:3;
        u32 rd_rsp_dly:3;
        u32 wr_cmd_dly:3;
        u32 wr_dat_dly:3;
        u32 clk_dly:3;
};

#define SPMMC_DMA_MODE 0
#define SPMMC_PIO_MODE 1

struct spmmc_host {
        void __iomem *base;
        struct clk *clk;
        struct reset_control *rstc;
        struct mmc_host *mmc;
        struct mmc_request *mrq; /* current mrq */
        int irq;
        int dmapio_mode;
        struct spmmc_tuning_info tuning_info;
        int dma_int_threshold;
        int dma_use_int;
};

static inline int spmmc_wait_finish(struct spmmc_host *host)
{
        u32 state;

        return readl_poll_timeout(host->base + SPMMC_SD_STATE_REG, state,
                                        (state & SPMMC_SDSTATE_FINISH),
                                        SPMMC_POLL_DELAY_US, SPMMC_TIMEOUT_US);
}

static inline int spmmc_wait_sdstatus(struct spmmc_host *host, unsigned int status_bit)
{
        u32 status;

        return readl_poll_timeout(host->base + SPMMC_SD_STATUS_REG, status,
                                        (status & status_bit),
                                        SPMMC_POLL_DELAY_US, SPMMC_TIMEOUT_US);
}

#define spmmc_wait_rspbuf_full(host) spmmc_wait_sdstatus(host, SPMMC_SDSTATUS_RSP_BUF_FULL)
#define spmmc_wait_rxbuf_full(host) spmmc_wait_sdstatus(host, SPMMC_SDSTATUS_RX_DATA_BUF_FULL)
#define spmmc_wait_txbuf_empty(host) spmmc_wait_sdstatus(host, SPMMC_SDSTATUS_TX_DATA_BUF_EMPTY)

static void spmmc_get_rsp(struct spmmc_host *host, struct mmc_command *cmd)
{
        u32 value0_3, value4_5;

        if (!(cmd->flags & MMC_RSP_PRESENT))
                return;
        if (cmd->flags & MMC_RSP_136) {
                if (spmmc_wait_rspbuf_full(host))
                        return;
                value0_3 = readl(host->base + SPMMC_SD_RSPBUF0_3_REG);
                value4_5 = readl(host->base + SPMMC_SD_RSPBUF4_5_REG) & 0xffff;
                cmd->resp[0] = (value0_3 << 8) | (value4_5 >> 8);
                cmd->resp[1] = value4_5 << 24;
                value0_3 = readl(host->base + SPMMC_SD_RSPBUF0_3_REG);
                value4_5 = readl(host->base + SPMMC_SD_RSPBUF4_5_REG) & 0xffff;
                cmd->resp[1] |= value0_3 >> 8;
                cmd->resp[2] = value0_3 << 24;
                cmd->resp[2] |= value4_5 << 8;
                value0_3 = readl(host->base + SPMMC_SD_RSPBUF0_3_REG);
                value4_5 = readl(host->base + SPMMC_SD_RSPBUF4_5_REG) & 0xffff;
                cmd->resp[2] |= value0_3 >> 24;
                cmd->resp[3] = value0_3 << 8;
                cmd->resp[3] |= value4_5 >> 8;
        } else {
                if (spmmc_wait_rspbuf_full(host))
                        return;
                value0_3 = readl(host->base + SPMMC_SD_RSPBUF0_3_REG);
                value4_5 = readl(host->base + SPMMC_SD_RSPBUF4_5_REG) & 0xffff;
                cmd->resp[0] = (value0_3 << 8) | (value4_5 >> 8);
                cmd->resp[1] = value4_5 << 24;
        }
}

static void spmmc_set_bus_clk(struct spmmc_host *host, int clk)
{
        unsigned int clkdiv;
        int f_min = host->mmc->f_min;
        int f_max = host->mmc->f_max;
        u32 value = readl(host->base + SPMMC_SD_CONFIG0_REG);

        if (clk < f_min)
                clk = f_min;
        if (clk > f_max)
                clk = f_max;

        clkdiv = (clk_get_rate(host->clk) + clk) / clk - 1;
        if (clkdiv > 0xfff)
                clkdiv = 0xfff;
        value &= ~SPMMC_CLOCK_DIVISION;
        value |= FIELD_PREP(SPMMC_CLOCK_DIVISION, clkdiv);
        writel(value, host->base + SPMMC_SD_CONFIG0_REG);
}

static void spmmc_set_bus_timing(struct spmmc_host *host, unsigned int timing)
{
        u32 value = readl(host->base + SPMMC_SD_CONFIG1_REG);
        int clkdiv = FIELD_GET(SPMMC_CLOCK_DIVISION, readl(host->base + SPMMC_SD_CONFIG0_REG));
        int delay = clkdiv / 2 < 7 ? clkdiv / 2 : 7;
        int hs_en = 1, ddr_enabled = 0;

        switch (timing) {
        case MMC_TIMING_LEGACY:
                hs_en = 0;
                break;
        case MMC_TIMING_MMC_HS:
        case MMC_TIMING_SD_HS:
        case MMC_TIMING_UHS_SDR50:
        case MMC_TIMING_UHS_SDR104:
        case MMC_TIMING_MMC_HS200:
                hs_en = 1;
                break;
        case MMC_TIMING_UHS_DDR50:
                ddr_enabled = 1;
                break;
        case MMC_TIMING_MMC_DDR52:
                ddr_enabled = 1;
                break;
        default:
                hs_en = 0;
                break;
        }

        if (hs_en) {
                value |= SPMMC_SD_HIGH_SPEED_EN;
                writel(value, host->base + SPMMC_SD_CONFIG1_REG);
                value = readl(host->base + SPMMC_SD_TIMING_CONFIG0_REG);
                value &= ~SPMMC_SD_WRITE_DATA_DELAY;
                value |= FIELD_PREP(SPMMC_SD_WRITE_DATA_DELAY, delay);
                value &= ~SPMMC_SD_WRITE_COMMAND_DELAY;
                value |= FIELD_PREP(SPMMC_SD_WRITE_COMMAND_DELAY, delay);
                writel(value, host->base + SPMMC_SD_TIMING_CONFIG0_REG);
        } else {
                value &= ~SPMMC_SD_HIGH_SPEED_EN;
                writel(value, host->base + SPMMC_SD_CONFIG1_REG);
        }
        if (ddr_enabled) {
                value = readl(host->base + SPMMC_SD_CONFIG0_REG);
                value |= SPMMC_SD_DDR_MODE;
                writel(value, host->base + SPMMC_SD_CONFIG0_REG);
        } else {
                value = readl(host->base + SPMMC_SD_CONFIG0_REG);
                value &= ~SPMMC_SD_DDR_MODE;
                writel(value, host->base + SPMMC_SD_CONFIG0_REG);
        }
}

static void spmmc_set_bus_width(struct spmmc_host *host, int width)
{
        u32 value = readl(host->base + SPMMC_SD_CONFIG0_REG);

        switch (width) {
        case MMC_BUS_WIDTH_8:
                value &= ~SPMMC_SD_DATA_WD;
                value |= SPMMC_MMC8_EN;
                break;
        case MMC_BUS_WIDTH_4:
                value |= SPMMC_SD_DATA_WD;
                value &= ~SPMMC_MMC8_EN;
                break;
        default:
                value &= ~SPMMC_SD_DATA_WD;
                value &= ~SPMMC_MMC8_EN;
                break;
        }
        writel(value, host->base + SPMMC_SD_CONFIG0_REG);
}

/*
 * select the working mode of controller: sd/sdio/emmc
 */
static void spmmc_set_sdmmc_mode(struct spmmc_host *host)
{
        u32 value = readl(host->base + SPMMC_SD_CONFIG0_REG);

        value |= SPMMC_SD_MMC_MODE;
        value &= ~SPMMC_SDIO_MODE;
        writel(value, host->base + SPMMC_SD_CONFIG0_REG);
}

static void spmmc_sw_reset(struct spmmc_host *host)
{
        u32 value;

        /*
         * Must reset dma operation first, or it will
         * be stuck on sd_state == 0x1c00 because of
         * a controller software reset bug
         */
        value = readl(host->base + SPMMC_HW_DMA_CTRL_REG);
        value |= SPMMC_DMAIDLE;
        writel(value, host->base + SPMMC_HW_DMA_CTRL_REG);
        value &= ~SPMMC_DMAIDLE;
        writel(value, host->base + SPMMC_HW_DMA_CTRL_REG);
        value = readl(host->base + SPMMC_HW_DMA_CTRL_REG);
        value |= SPMMC_HW_DMA_RST;
        writel(value, host->base + SPMMC_HW_DMA_CTRL_REG);
        writel(0x7, host->base + SPMMC_SD_RST_REG);
        readl_poll_timeout_atomic(host->base + SPMMC_SD_HW_STATE_REG, value,
                                  !(value & BIT(6)), 1, SPMMC_TIMEOUT_US);
}

static void spmmc_prepare_cmd(struct spmmc_host *host, struct mmc_command *cmd)
{
        u32 value;

        /* add start bit, according to spec, command format */
        value = ((cmd->opcode | 0x40) << 24) | (cmd->arg >> 8);
        writel(value, host->base + SPMMC_SD_CMDBUF0_3_REG);
        writeb(cmd->arg & 0xff, host->base + SPMMC_SD_CMDBUF4_REG);

        /* disable interrupt if needed */
        value = readl(host->base + SPMMC_SD_INT_REG);
        value |= SPMMC_SDINT_SDCMPCLR;
        value &= ~SPMMC_SDINT_SDCMPEN;
        writel(value, host->base + SPMMC_SD_INT_REG);

        value = readl(host->base + SPMMC_SD_CONFIG0_REG);
        value &= ~SPMMC_SD_TRANS_MODE;
        value |= SPMMC_SD_CMD_DUMMY;
        if (cmd->flags & MMC_RSP_PRESENT) {
                value |= SPMMC_SD_AUTO_RESPONSE;
        } else {
                value &= ~SPMMC_SD_AUTO_RESPONSE;
                writel(value, host->base + SPMMC_SD_CONFIG0_REG);

                return;
        }
        /*
         * Currently, host is not capable of checking R2's CRC7,
         * thus, enable crc7 check only for 48 bit response commands
         */
        if (cmd->flags & MMC_RSP_CRC && !(cmd->flags & MMC_RSP_136))
                value |= SPMMC_SD_RSP_CHK_EN;
        else
                value &= ~SPMMC_SD_RSP_CHK_EN;

        if (cmd->flags & MMC_RSP_136)
                value |= SPMMC_SD_RSP_TYPE;
        else
                value &= ~SPMMC_SD_RSP_TYPE;
        writel(value, host->base + SPMMC_SD_CONFIG0_REG);
}

static void spmmc_prepare_data(struct spmmc_host *host, struct mmc_data *data)
{
        u32 value, srcdst;

        writel(data->blocks - 1, host->base + SPMMC_SD_PAGE_NUM_REG);
        writel(data->blksz - 1, host->base + SPMMC_SD_BLOCKSIZE_REG);
        value = readl(host->base + SPMMC_SD_CONFIG0_REG);
        if (data->flags & MMC_DATA_READ) {
                value &= ~SPMMC_SD_TRANS_MODE;
                value |= FIELD_PREP(SPMMC_SD_TRANS_MODE, 2);
                value &= ~SPMMC_SD_AUTO_RESPONSE;
                value &= ~SPMMC_SD_CMD_DUMMY;
                srcdst = readl(host->base + SPMMC_CARD_MEDIATYPE_SRCDST_REG);
                srcdst &= ~SPMMC_DMA_SOURCE;
                srcdst |= FIELD_PREP(SPMMC_DMA_SOURCE, 0x2);
                srcdst &= ~SPMMC_DMA_DESTINATION;
                srcdst |= FIELD_PREP(SPMMC_DMA_DESTINATION, 0x1);
                writel(srcdst, host->base + SPMMC_CARD_MEDIATYPE_SRCDST_REG);
        } else {
                value &= ~SPMMC_SD_TRANS_MODE;
                value |= FIELD_PREP(SPMMC_SD_TRANS_MODE, 1);
                srcdst = readl(host->base + SPMMC_CARD_MEDIATYPE_SRCDST_REG);
                srcdst &= ~SPMMC_DMA_SOURCE;
                srcdst |= FIELD_PREP(SPMMC_DMA_SOURCE, 0x1);
                srcdst &= ~SPMMC_DMA_DESTINATION;
                srcdst |= FIELD_PREP(SPMMC_DMA_DESTINATION, 0x2);
                writel(srcdst, host->base + SPMMC_CARD_MEDIATYPE_SRCDST_REG);
        }

        value |= SPMMC_SD_LEN_MODE;
        if (host->dmapio_mode == SPMMC_DMA_MODE) {
                struct scatterlist *sg;
                dma_addr_t dma_addr;
                unsigned int dma_size;
                int i, count = 1;

                count = dma_map_sg(host->mmc->parent, data->sg, data->sg_len,
                                   mmc_get_dma_dir(data));
                if (!count || count > SPMMC_MAX_DMA_MEMORY_SECTORS) {
                        data->error = -EINVAL;

                        return;
                }
                for_each_sg(data->sg, sg, count, i) {
                        dma_addr = sg_dma_address(sg);
                        dma_size = sg_dma_len(sg) / data->blksz - 1;
                        if (i == 0) {
                                writel(dma_addr, host->base + SPMMC_DMA_BASE_ADDR_REG);
                                writel(dma_size, host->base + SPMMC_SDRAM_SECTOR_0_SIZE_REG);
                        } else if (i == 1) {
                                writel(dma_addr, host->base + SPMMC_SDRAM_SECTOR_1_ADDR_REG);
                                writel(dma_size, host->base + SPMMC_SDRAM_SECTOR_1_LENG_REG);
                        } else if (i == 2) {
                                writel(dma_addr, host->base + SPMMC_SDRAM_SECTOR_2_ADDR_REG);
                                writel(dma_size, host->base + SPMMC_SDRAM_SECTOR_2_LENG_REG);
                        } else if (i == 3) {
                                writel(dma_addr, host->base + SPMMC_SDRAM_SECTOR_3_ADDR_REG);
                                writel(dma_size, host->base + SPMMC_SDRAM_SECTOR_3_LENG_REG);
                        } else if (i == 4) {
                                writel(dma_addr, host->base + SPMMC_SDRAM_SECTOR_4_ADDR_REG);
                                writel(dma_size, host->base + SPMMC_SDRAM_SECTOR_4_LENG_REG);
                        } else if (i == 5) {
                                writel(dma_addr, host->base + SPMMC_SDRAM_SECTOR_5_ADDR_REG);
                                writel(dma_size, host->base + SPMMC_SDRAM_SECTOR_5_LENG_REG);
                        } else if (i == 6) {
                                writel(dma_addr, host->base + SPMMC_SDRAM_SECTOR_6_ADDR_REG);
                                writel(dma_size, host->base + SPMMC_SDRAM_SECTOR_6_LENG_REG);
                        } else if (i == 7) {
                                writel(dma_addr, host->base + SPMMC_SDRAM_SECTOR_7_ADDR_REG);
                                writel(dma_size, host->base + SPMMC_SDRAM_SECTOR_7_LENG_REG);
                        }
                }
                value &= ~SPMMC_SD_PIO_MODE;
                writel(value, host->base + SPMMC_SD_CONFIG0_REG);
                /* enable interrupt if needed */
                if (data->blksz * data->blocks > host->dma_int_threshold) {
                        host->dma_use_int = 1;
                        value = readl(host->base + SPMMC_SD_INT_REG);
                        value &= ~SPMMC_SDINT_SDCMPEN;
                        value |= FIELD_PREP(SPMMC_SDINT_SDCMPEN, 1); /* sdcmpen */
                        writel(value, host->base + SPMMC_SD_INT_REG);
                }
        } else {
                value |= SPMMC_SD_PIO_MODE;
                value |= SPMMC_RX4_EN;
                writel(value, host->base + SPMMC_SD_CONFIG0_REG);
        }
}

static inline void spmmc_trigger_transaction(struct spmmc_host *host)
{
        u32 value = readl(host->base + SPMMC_SD_CTRL_REG);

        value |= SPMMC_NEW_COMMAND_TRIGGER;
        writel(value, host->base + SPMMC_SD_CTRL_REG);
}

static void spmmc_send_stop_cmd(struct spmmc_host *host)
{
        struct mmc_command stop = {};
        u32 value;

        stop.opcode = MMC_STOP_TRANSMISSION;
        stop.arg = 0;
        stop.flags = MMC_RSP_R1B;
        spmmc_prepare_cmd(host, &stop);
        value = readl(host->base + SPMMC_SD_INT_REG);
        value &= ~SPMMC_SDINT_SDCMPEN;
        value |= FIELD_PREP(SPMMC_SDINT_SDCMPEN, 0);
        writel(value, host->base + SPMMC_SD_INT_REG);
        spmmc_trigger_transaction(host);
        readl_poll_timeout(host->base + SPMMC_SD_STATE_REG, value,
                           (value & SPMMC_SDSTATE_FINISH), 1, SPMMC_TIMEOUT_US);
}

static int spmmc_check_error(struct spmmc_host *host, struct mmc_request *mrq)
{
        int ret = 0;
        struct mmc_command *cmd = mrq->cmd;
        struct mmc_data *data = mrq->data;

        u32 value = readl(host->base + SPMMC_SD_STATE_REG);
        u32 crc_token = FIELD_GET(SPMMC_CRCTOKEN_CHECK_RESULT, value);

        if (value & SPMMC_SDSTATE_ERROR) {
                u32 timing_cfg0 = 0;

                value = readl(host->base + SPMMC_SD_STATUS_REG);

                if (host->tuning_info.enable_tuning) {
                        timing_cfg0 = readl(host->base + SPMMC_SD_TIMING_CONFIG0_REG);
                        host->tuning_info.rd_crc_dly = FIELD_GET(SPMMC_SD_READ_CRC_DELAY,
                                                                 timing_cfg0);
                        host->tuning_info.rd_dat_dly = FIELD_GET(SPMMC_SD_READ_DATA_DELAY,
                                                                 timing_cfg0);
                        host->tuning_info.rd_rsp_dly = FIELD_GET(SPMMC_SD_READ_RESPONSE_DELAY,
                                                                 timing_cfg0);
                        host->tuning_info.wr_cmd_dly = FIELD_GET(SPMMC_SD_WRITE_COMMAND_DELAY,
                                                                 timing_cfg0);
                        host->tuning_info.wr_dat_dly = FIELD_GET(SPMMC_SD_WRITE_DATA_DELAY,
                                                                 timing_cfg0);
                }

                if (value & SPMMC_SDSTATUS_RSP_TIMEOUT) {
                        ret = -ETIMEDOUT;
                        host->tuning_info.wr_cmd_dly++;
                } else if (value & SPMMC_SDSTATUS_RSP_CRC7_ERROR) {
                        ret = -EILSEQ;
                        host->tuning_info.rd_rsp_dly++;
                } else if (data) {
                        if ((value & SPMMC_SDSTATUS_STB_TIMEOUT)) {
                                ret = -ETIMEDOUT;
                                host->tuning_info.rd_dat_dly++;
                        } else if (value & SPMMC_SDSTATUS_RDATA_CRC16_ERROR) {
                                ret = -EILSEQ;
                                host->tuning_info.rd_dat_dly++;
                        } else if (value & SPMMC_SDSTATUS_CARD_CRC_CHECK_TIMEOUT) {
                                ret = -ETIMEDOUT;
                                host->tuning_info.rd_crc_dly++;
                        } else if (value & SPMMC_SDSTATUS_CRC_TOKEN_CHECK_ERROR) {
                                ret = -EILSEQ;
                                if (crc_token == 0x5)
                                        host->tuning_info.wr_dat_dly++;
                                else
                                        host->tuning_info.rd_crc_dly++;
                        }
                }
                cmd->error = ret;
                if (data) {
                        data->error = ret;
                        data->bytes_xfered = 0;
                }
                if (!host->tuning_info.need_tuning && host->tuning_info.enable_tuning)
                        cmd->retries = SPMMC_MAX_RETRIES;
                spmmc_sw_reset(host);

                if (host->tuning_info.enable_tuning) {
                        timing_cfg0 &= ~SPMMC_SD_READ_CRC_DELAY;
                        timing_cfg0 |= FIELD_PREP(SPMMC_SD_READ_CRC_DELAY,
                                                       host->tuning_info.rd_crc_dly);
                        timing_cfg0 &= ~SPMMC_SD_READ_DATA_DELAY;
                        timing_cfg0 |= FIELD_PREP(SPMMC_SD_READ_DATA_DELAY,
                                                       host->tuning_info.rd_dat_dly);
                        timing_cfg0 &= ~SPMMC_SD_READ_RESPONSE_DELAY;
                        timing_cfg0 |= FIELD_PREP(SPMMC_SD_READ_RESPONSE_DELAY,
                                                       host->tuning_info.rd_rsp_dly);
                        timing_cfg0 &= ~SPMMC_SD_WRITE_COMMAND_DELAY;
                        timing_cfg0 |= FIELD_PREP(SPMMC_SD_WRITE_COMMAND_DELAY,
                                                       host->tuning_info.wr_cmd_dly);
                        timing_cfg0 &= ~SPMMC_SD_WRITE_DATA_DELAY;
                        timing_cfg0 |= FIELD_PREP(SPMMC_SD_WRITE_DATA_DELAY,
                                                       host->tuning_info.wr_dat_dly);
                        writel(timing_cfg0, host->base + SPMMC_SD_TIMING_CONFIG0_REG);
                }
        } else if (data) {
                data->error = 0;
                data->bytes_xfered = data->blocks * data->blksz;
        }
        host->tuning_info.need_tuning = ret;

        return ret;
}

/*
 * the strategy is:
 * 1. if several continuous delays are acceptable, we choose a middle one;
 * 2. otherwise, we choose the first one.
 */
static inline int spmmc_find_best_delay(u8 candidate_dly)
{
        int f, w, value;

        if (!candidate_dly)
                return 0;
        f = ffs(candidate_dly) - 1;
        w = hweight8(candidate_dly);
        value = ((1 << w) - 1) << f;
        if (0xff == (value & ~candidate_dly))
                return (f + w / 2);
        else
                return (f);
}

static void spmmc_xfer_data_pio(struct spmmc_host *host, struct mmc_data *data)
{
        u32 *buf;
        int data_left = data->blocks * data->blksz;
        int consumed, remain;

        struct sg_mapping_iter sg_miter;
        unsigned int flags = 0;

        if (data->flags & MMC_DATA_WRITE)
                flags |= SG_MITER_FROM_SG;
        else
                flags |= SG_MITER_TO_SG;
        sg_miter_start(&sg_miter, data->sg, data->sg_len, flags);
        while (data_left > 0) {
                consumed = 0;
                if (!sg_miter_next(&sg_miter))
                        break;
                buf = sg_miter.addr;
                remain = sg_miter.length;
                do {
                        if (data->flags & MMC_DATA_WRITE) {
                                if (spmmc_wait_txbuf_empty(host))
                                        goto done;
                                writel(*buf, host->base + SPMMC_SD_PIODATATX_REG);
                        } else {
                                if (spmmc_wait_rxbuf_full(host))
                                        goto done;
                                *buf = readl(host->base + SPMMC_SD_PIODATARX_REG);
                        }
                        buf++;
                        /* tx/rx 4 bytes one time in pio mode */
                        consumed += 4;
                        remain -= 4;
                } while (remain);
                sg_miter.consumed = consumed;
                data_left -= consumed;
        }
done:
        sg_miter_stop(&sg_miter);
}

static void spmmc_controller_init(struct spmmc_host *host)
{
        u32 value;
        int ret = reset_control_assert(host->rstc);

        if (!ret) {
                usleep_range(1000, 1250);
                ret = reset_control_deassert(host->rstc);
        }

        value = readl(host->base + SPMMC_CARD_MEDIATYPE_SRCDST_REG);
        value &= ~SPMMC_MEDIA_TYPE;
        value |= FIELD_PREP(SPMMC_MEDIA_TYPE, SPMMC_MEDIA_SD);
        writel(value, host->base + SPMMC_CARD_MEDIATYPE_SRCDST_REG);
}

/*
 * 1. unmap scatterlist if needed;
 * 2. get response & check error conditions;
 * 3. notify mmc layer the request is done
 */
static void spmmc_finish_request(struct spmmc_host *host, struct mmc_request *mrq)
{
        struct mmc_command *cmd;
        struct mmc_data *data;

        if (!mrq)
                return;

        cmd = mrq->cmd;
        data = mrq->data;

        if (data && SPMMC_DMA_MODE == host->dmapio_mode) {
                dma_unmap_sg(host->mmc->parent, data->sg, data->sg_len, mmc_get_dma_dir(data));
                host->dma_use_int = 0;
        }

        spmmc_get_rsp(host, cmd);
        spmmc_check_error(host, mrq);
        if (mrq->stop)
                spmmc_send_stop_cmd(host);

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

/* Interrupt Service Routine */
static irqreturn_t spmmc_irq(int irq, void *dev_id)
{
        struct spmmc_host *host = dev_id;
        u32 value = readl(host->base + SPMMC_SD_INT_REG);

        if ((value & SPMMC_SDINT_SDCMP) && (value & SPMMC_SDINT_SDCMPEN)) {
                value &= ~SPMMC_SDINT_SDCMPEN;
                value |= SPMMC_SDINT_SDCMPCLR;
                writel(value, host->base + SPMMC_SD_INT_REG);
                return IRQ_WAKE_THREAD;
        }
        return IRQ_HANDLED;
}

static void spmmc_request(struct mmc_host *mmc, struct mmc_request *mrq)
{
        struct spmmc_host *host = mmc_priv(mmc);
        struct mmc_data *data;
        struct mmc_command *cmd;

        host->mrq = mrq;
        data = mrq->data;
        cmd = mrq->cmd;

        spmmc_prepare_cmd(host, cmd);
        /* we need manually read response R2. */
        if (cmd->flags & MMC_RSP_136) {
                spmmc_trigger_transaction(host);
                spmmc_get_rsp(host, cmd);
                spmmc_wait_finish(host);
                spmmc_check_error(host, mrq);
                host->mrq = NULL;
                mmc_request_done(host->mmc, mrq);
        } else {
                if (data)
                        spmmc_prepare_data(host, data);

                if (host->dmapio_mode == SPMMC_PIO_MODE && data) {
                        u32 value;
                        /* pio data transfer do not use interrupt */
                        value = readl(host->base + SPMMC_SD_INT_REG);
                        value &= ~SPMMC_SDINT_SDCMPEN;
                        writel(value, host->base + SPMMC_SD_INT_REG);
                        spmmc_trigger_transaction(host);
                        spmmc_xfer_data_pio(host, data);
                        spmmc_wait_finish(host);
                        spmmc_finish_request(host, mrq);
                } else {
                        if (host->dma_use_int) {
                                spmmc_trigger_transaction(host);
                        } else {
                                spmmc_trigger_transaction(host);
                                spmmc_wait_finish(host);
                                spmmc_finish_request(host, mrq);
                        }
                }
        }
}

static void spmmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
{
        struct spmmc_host *host = (struct spmmc_host *)mmc_priv(mmc);

        spmmc_set_bus_clk(host, ios->clock);
        spmmc_set_bus_timing(host, ios->timing);
        spmmc_set_bus_width(host, ios->bus_width);
        /* ensure mode is correct, because we might have hw reset the controller */
        spmmc_set_sdmmc_mode(host);
}

/*
 * Return values for the get_cd callback should be:
 *   0 for a absent card
 *   1 for a present card
 *   -ENOSYS when not supported (equal to NULL callback)
 *   or a negative errno value when something bad happened
 */
static int spmmc_get_cd(struct mmc_host *mmc)
{
        int ret = 0;

        if (mmc_host_can_gpio_cd(mmc))
                ret = mmc_gpio_get_cd(mmc);

        if (ret < 0)
                ret = 0;

        return ret;
}

static int spmmc_execute_tuning(struct mmc_host *mmc, u32 opcode)
{
        struct spmmc_host *host = mmc_priv(mmc);
        u8 smpl_dly = 0, candidate_dly = 0;
        u32 value;

        host->tuning_info.enable_tuning = 0;
        do {
                value = readl(host->base + SPMMC_SD_TIMING_CONFIG0_REG);
                value &= ~SPMMC_SD_READ_RESPONSE_DELAY;
                value |= FIELD_PREP(SPMMC_SD_READ_RESPONSE_DELAY, smpl_dly);
                value &= ~SPMMC_SD_READ_DATA_DELAY;
                value |= FIELD_PREP(SPMMC_SD_READ_DATA_DELAY, smpl_dly);
                value &= ~SPMMC_SD_READ_CRC_DELAY;
                value |= FIELD_PREP(SPMMC_SD_READ_CRC_DELAY, smpl_dly);
                writel(value, host->base + SPMMC_SD_TIMING_CONFIG0_REG);

                if (!mmc_send_tuning(mmc, opcode, NULL)) {
                        candidate_dly |= (1 << smpl_dly);
                        break;
                }
        } while (smpl_dly++ <= SPMMC_MAX_TUNABLE_DLY);
        host->tuning_info.enable_tuning = 1;

        if (candidate_dly) {
                smpl_dly = spmmc_find_best_delay(candidate_dly);
                value = readl(host->base + SPMMC_SD_TIMING_CONFIG0_REG);
                value &= ~SPMMC_SD_READ_RESPONSE_DELAY;
                value |= FIELD_PREP(SPMMC_SD_READ_RESPONSE_DELAY, smpl_dly);
                value &= ~SPMMC_SD_READ_DATA_DELAY;
                value |= FIELD_PREP(SPMMC_SD_READ_DATA_DELAY, smpl_dly);
                value &= ~SPMMC_SD_READ_CRC_DELAY;
                value |= FIELD_PREP(SPMMC_SD_READ_CRC_DELAY, smpl_dly);
                writel(value, host->base + SPMMC_SD_TIMING_CONFIG0_REG);
                return 0;
        }

        return -EIO;
}

static const struct mmc_host_ops spmmc_ops = {
        .request = spmmc_request,
        .set_ios = spmmc_set_ios,
        .get_cd = spmmc_get_cd,
        .execute_tuning = spmmc_execute_tuning,
};

static irqreturn_t spmmc_func_finish_req(int irq, void *dev_id)
{
        struct spmmc_host *host = dev_id;

        spmmc_finish_request(host, host->mrq);

        return IRQ_HANDLED;
}

static int spmmc_drv_probe(struct platform_device *pdev)
{
        struct mmc_host *mmc;
        struct resource *res;
        struct spmmc_host *host;
        int ret = 0;

        mmc = devm_mmc_alloc_host(&pdev->dev, sizeof(struct spmmc_host));
        if (!mmc)
                return -ENOMEM;

        host = mmc_priv(mmc);
        host->mmc = mmc;
        host->dmapio_mode = SPMMC_DMA_MODE;
        host->dma_int_threshold = 1024;

        host->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
        if (IS_ERR(host->base))
                return PTR_ERR(host->base);

        host->clk = devm_clk_get(&pdev->dev, NULL);
        if (IS_ERR(host->clk))
                return dev_err_probe(&pdev->dev, PTR_ERR(host->clk), "clk get fail\n");

        host->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
        if (IS_ERR(host->rstc))
                return dev_err_probe(&pdev->dev, PTR_ERR(host->rstc), "rst get fail\n");

        host->irq = platform_get_irq(pdev, 0);
        if (host->irq < 0)
                return host->irq;

        ret = devm_request_threaded_irq(&pdev->dev, host->irq,
                                        spmmc_irq, spmmc_func_finish_req, IRQF_SHARED,
                        NULL, host);
        if (ret)
                return ret;

        ret = clk_prepare_enable(host->clk);
        if (ret)
                return dev_err_probe(&pdev->dev, ret, "failed to enable clk\n");

        ret = mmc_of_parse(mmc);
        if (ret)
                goto clk_disable;

        mmc->ops = &spmmc_ops;
        mmc->f_min = SPMMC_MIN_CLK;
        if (mmc->f_max > SPMMC_MAX_CLK)
                mmc->f_max = SPMMC_MAX_CLK;

        ret = mmc_regulator_get_supply(mmc);
        if (ret)
                goto clk_disable;

        if (!mmc->ocr_avail)
                mmc->ocr_avail = MMC_VDD_32_33 | MMC_VDD_33_34;
        mmc->max_seg_size = SPMMC_MAX_BLK_COUNT * 512;
        mmc->max_segs = SPMMC_MAX_DMA_MEMORY_SECTORS;
        mmc->max_req_size = SPMMC_MAX_BLK_COUNT * 512;
        mmc->max_blk_size = 512;
        mmc->max_blk_count = SPMMC_MAX_BLK_COUNT;

        dev_set_drvdata(&pdev->dev, host);
        spmmc_controller_init(host);
        spmmc_set_sdmmc_mode(host);
        host->tuning_info.enable_tuning = 1;
        pm_runtime_set_active(&pdev->dev);
        pm_runtime_enable(&pdev->dev);
        ret = mmc_add_host(mmc);
        if (ret)
                goto pm_disable;

        return 0;

pm_disable:
        pm_runtime_disable(&pdev->dev);

clk_disable:
        clk_disable_unprepare(host->clk);
        return ret;
}

static void spmmc_drv_remove(struct platform_device *dev)
{
        struct spmmc_host *host = platform_get_drvdata(dev);

        mmc_remove_host(host->mmc);
        pm_runtime_get_sync(&dev->dev);
        clk_disable_unprepare(host->clk);
        pm_runtime_put_noidle(&dev->dev);
        pm_runtime_disable(&dev->dev);
}

static int spmmc_pm_runtime_suspend(struct device *dev)
{
        struct spmmc_host *host;

        host = dev_get_drvdata(dev);
        clk_disable_unprepare(host->clk);

        return 0;
}

static int spmmc_pm_runtime_resume(struct device *dev)
{
        struct spmmc_host *host;

        host = dev_get_drvdata(dev);

        return clk_prepare_enable(host->clk);
}

static DEFINE_RUNTIME_DEV_PM_OPS(spmmc_pm_ops, spmmc_pm_runtime_suspend,
                                                        spmmc_pm_runtime_resume, NULL);

static const struct of_device_id spmmc_of_table[] = {
        {
                .compatible = "sunplus,sp7021-mmc",
        },
        {/* sentinel */}
};
MODULE_DEVICE_TABLE(of, spmmc_of_table);

static struct platform_driver spmmc_driver = {
        .probe = spmmc_drv_probe,
        .remove = spmmc_drv_remove,
        .driver = {
                .name = "spmmc",
                .pm = pm_ptr(&spmmc_pm_ops),
                .of_match_table = spmmc_of_table,
        },
};
module_platform_driver(spmmc_driver);

MODULE_AUTHOR("Tony Huang <tonyhuang.sunplus@gmail.com>");
MODULE_AUTHOR("Li-hao Kuo <lhjeff911@gmail.com>");
MODULE_DESCRIPTION("Sunplus MMC controller driver");
MODULE_LICENSE("GPL");