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  •  * Copyright (C) 2017, STMicroelectronics - All Rights Reserved
     * Author(s): Patrice Chotard, <patrice.chotard@st.com> for STMicroelectronics.
    
     *
     * SPDX-License-Identifier:	GPL-2.0+
     */
    
    #include <common.h>
    #include <clk.h>
    #include <dm.h>
    #include <fdtdec.h>
    
    #include <mmc.h>
    #include <reset.h>
    #include <asm/io.h>
    #include <asm/gpio.h>
    #include <linux/iopoll.h>
    
    struct stm32_sdmmc2_plat {
    	struct mmc_config cfg;
    	struct mmc mmc;
    };
    
    struct stm32_sdmmc2_priv {
    	fdt_addr_t base;
    	struct clk clk;
    	struct reset_ctl reset_ctl;
    	struct gpio_desc cd_gpio;
    	u32 clk_reg_msk;
    	u32 pwr_reg_msk;
    };
    
    struct stm32_sdmmc2_ctx {
    	u32 cache_start;
    	u32 cache_end;
    	u32 data_length;
    	bool dpsm_abort;
    };
    
    /* SDMMC REGISTERS OFFSET */
    #define SDMMC_POWER		0x00	/* SDMMC power control             */
    #define SDMMC_CLKCR		0x04	/* SDMMC clock control             */
    #define SDMMC_ARG		0x08	/* SDMMC argument                  */
    #define SDMMC_CMD		0x0C	/* SDMMC command                   */
    #define SDMMC_RESP1		0x14	/* SDMMC response 1                */
    #define SDMMC_RESP2		0x18	/* SDMMC response 2                */
    #define SDMMC_RESP3		0x1C	/* SDMMC response 3                */
    #define SDMMC_RESP4		0x20	/* SDMMC response 4                */
    #define SDMMC_DTIMER		0x24	/* SDMMC data timer                */
    #define SDMMC_DLEN		0x28	/* SDMMC data length               */
    #define SDMMC_DCTRL		0x2C	/* SDMMC data control              */
    #define SDMMC_DCOUNT		0x30	/* SDMMC data counter              */
    #define SDMMC_STA		0x34	/* SDMMC status                    */
    #define SDMMC_ICR		0x38	/* SDMMC interrupt clear           */
    #define SDMMC_MASK		0x3C	/* SDMMC mask                      */
    #define SDMMC_IDMACTRL		0x50	/* SDMMC DMA control               */
    #define SDMMC_IDMABASE0		0x58	/* SDMMC DMA buffer 0 base address */
    
    /* SDMMC_POWER register */
    #define SDMMC_POWER_PWRCTRL		GENMASK(1, 0)
    #define SDMMC_POWER_VSWITCH		BIT(2)
    #define SDMMC_POWER_VSWITCHEN		BIT(3)
    #define SDMMC_POWER_DIRPOL		BIT(4)
    
    /* SDMMC_CLKCR register */
    #define SDMMC_CLKCR_CLKDIV		GENMASK(9, 0)
    #define SDMMC_CLKCR_CLKDIV_MAX		SDMMC_CLKCR_CLKDIV
    #define SDMMC_CLKCR_PWRSAV		BIT(12)
    #define SDMMC_CLKCR_WIDBUS_4		BIT(14)
    #define SDMMC_CLKCR_WIDBUS_8		BIT(15)
    #define SDMMC_CLKCR_NEGEDGE		BIT(16)
    #define SDMMC_CLKCR_HWFC_EN		BIT(17)
    #define SDMMC_CLKCR_DDR			BIT(18)
    #define SDMMC_CLKCR_BUSSPEED		BIT(19)
    
    #define SDMMC_CLKCR_SELCLKRX_MASK	GENMASK(21, 20)
    #define SDMMC_CLKCR_SELCLKRX_CK		0
    #define SDMMC_CLKCR_SELCLKRX_CKIN	BIT(20)
    #define SDMMC_CLKCR_SELCLKRX_FBCK	BIT(21)
    
    
    /* SDMMC_CMD register */
    #define SDMMC_CMD_CMDINDEX		GENMASK(5, 0)
    #define SDMMC_CMD_CMDTRANS		BIT(6)
    #define SDMMC_CMD_CMDSTOP		BIT(7)
    #define SDMMC_CMD_WAITRESP		GENMASK(9, 8)
    #define SDMMC_CMD_WAITRESP_0		BIT(8)
    #define SDMMC_CMD_WAITRESP_1		BIT(9)
    #define SDMMC_CMD_WAITINT		BIT(10)
    #define SDMMC_CMD_WAITPEND		BIT(11)
    #define SDMMC_CMD_CPSMEN		BIT(12)
    #define SDMMC_CMD_DTHOLD		BIT(13)
    #define SDMMC_CMD_BOOTMODE		BIT(14)
    #define SDMMC_CMD_BOOTEN		BIT(15)
    #define SDMMC_CMD_CMDSUSPEND		BIT(16)
    
    /* SDMMC_DCTRL register */
    #define SDMMC_DCTRL_DTEN		BIT(0)
    #define SDMMC_DCTRL_DTDIR		BIT(1)
    #define SDMMC_DCTRL_DTMODE		GENMASK(3, 2)
    #define SDMMC_DCTRL_DBLOCKSIZE		GENMASK(7, 4)
    #define SDMMC_DCTRL_DBLOCKSIZE_SHIFT	4
    #define SDMMC_DCTRL_RWSTART		BIT(8)
    #define SDMMC_DCTRL_RWSTOP		BIT(9)
    #define SDMMC_DCTRL_RWMOD		BIT(10)
    #define SDMMC_DCTRL_SDMMCEN		BIT(11)
    #define SDMMC_DCTRL_BOOTACKEN		BIT(12)
    #define SDMMC_DCTRL_FIFORST		BIT(13)
    
    /* SDMMC_STA register */
    #define SDMMC_STA_CCRCFAIL		BIT(0)
    #define SDMMC_STA_DCRCFAIL		BIT(1)
    #define SDMMC_STA_CTIMEOUT		BIT(2)
    #define SDMMC_STA_DTIMEOUT		BIT(3)
    #define SDMMC_STA_TXUNDERR		BIT(4)
    #define SDMMC_STA_RXOVERR		BIT(5)
    #define SDMMC_STA_CMDREND		BIT(6)
    #define SDMMC_STA_CMDSENT		BIT(7)
    #define SDMMC_STA_DATAEND		BIT(8)
    #define SDMMC_STA_DHOLD			BIT(9)
    #define SDMMC_STA_DBCKEND		BIT(10)
    #define SDMMC_STA_DABORT		BIT(11)
    #define SDMMC_STA_DPSMACT		BIT(12)
    #define SDMMC_STA_CPSMACT		BIT(13)
    #define SDMMC_STA_TXFIFOHE		BIT(14)
    #define SDMMC_STA_RXFIFOHF		BIT(15)
    #define SDMMC_STA_TXFIFOF		BIT(16)
    #define SDMMC_STA_RXFIFOF		BIT(17)
    #define SDMMC_STA_TXFIFOE		BIT(18)
    #define SDMMC_STA_RXFIFOE		BIT(19)
    #define SDMMC_STA_BUSYD0		BIT(20)
    #define SDMMC_STA_BUSYD0END		BIT(21)
    #define SDMMC_STA_SDMMCIT		BIT(22)
    #define SDMMC_STA_ACKFAIL		BIT(23)
    #define SDMMC_STA_ACKTIMEOUT		BIT(24)
    #define SDMMC_STA_VSWEND		BIT(25)
    #define SDMMC_STA_CKSTOP		BIT(26)
    #define SDMMC_STA_IDMATE		BIT(27)
    #define SDMMC_STA_IDMABTC		BIT(28)
    
    /* SDMMC_ICR register */
    #define SDMMC_ICR_CCRCFAILC		BIT(0)
    #define SDMMC_ICR_DCRCFAILC		BIT(1)
    #define SDMMC_ICR_CTIMEOUTC		BIT(2)
    #define SDMMC_ICR_DTIMEOUTC		BIT(3)
    #define SDMMC_ICR_TXUNDERRC		BIT(4)
    #define SDMMC_ICR_RXOVERRC		BIT(5)
    #define SDMMC_ICR_CMDRENDC		BIT(6)
    #define SDMMC_ICR_CMDSENTC		BIT(7)
    #define SDMMC_ICR_DATAENDC		BIT(8)
    #define SDMMC_ICR_DHOLDC		BIT(9)
    #define SDMMC_ICR_DBCKENDC		BIT(10)
    #define SDMMC_ICR_DABORTC		BIT(11)
    #define SDMMC_ICR_BUSYD0ENDC		BIT(21)
    #define SDMMC_ICR_SDMMCITC		BIT(22)
    #define SDMMC_ICR_ACKFAILC		BIT(23)
    #define SDMMC_ICR_ACKTIMEOUTC		BIT(24)
    #define SDMMC_ICR_VSWENDC		BIT(25)
    #define SDMMC_ICR_CKSTOPC		BIT(26)
    #define SDMMC_ICR_IDMATEC		BIT(27)
    #define SDMMC_ICR_IDMABTCC		BIT(28)
    #define SDMMC_ICR_STATIC_FLAGS		((GENMASK(28, 21)) | (GENMASK(11, 0)))
    
    /* SDMMC_MASK register */
    #define SDMMC_MASK_CCRCFAILIE		BIT(0)
    #define SDMMC_MASK_DCRCFAILIE		BIT(1)
    #define SDMMC_MASK_CTIMEOUTIE		BIT(2)
    #define SDMMC_MASK_DTIMEOUTIE		BIT(3)
    #define SDMMC_MASK_TXUNDERRIE		BIT(4)
    #define SDMMC_MASK_RXOVERRIE		BIT(5)
    #define SDMMC_MASK_CMDRENDIE		BIT(6)
    #define SDMMC_MASK_CMDSENTIE		BIT(7)
    #define SDMMC_MASK_DATAENDIE		BIT(8)
    #define SDMMC_MASK_DHOLDIE		BIT(9)
    #define SDMMC_MASK_DBCKENDIE		BIT(10)
    #define SDMMC_MASK_DABORTIE		BIT(11)
    #define SDMMC_MASK_TXFIFOHEIE		BIT(14)
    #define SDMMC_MASK_RXFIFOHFIE		BIT(15)
    #define SDMMC_MASK_RXFIFOFIE		BIT(17)
    #define SDMMC_MASK_TXFIFOEIE		BIT(18)
    #define SDMMC_MASK_BUSYD0ENDIE		BIT(21)
    #define SDMMC_MASK_SDMMCITIE		BIT(22)
    #define SDMMC_MASK_ACKFAILIE		BIT(23)
    #define SDMMC_MASK_ACKTIMEOUTIE		BIT(24)
    #define SDMMC_MASK_VSWENDIE		BIT(25)
    #define SDMMC_MASK_CKSTOPIE		BIT(26)
    #define SDMMC_MASK_IDMABTCIE		BIT(28)
    
    /* SDMMC_IDMACTRL register */
    #define SDMMC_IDMACTRL_IDMAEN		BIT(0)
    
    #define SDMMC_CMD_TIMEOUT		0xFFFFFFFF
    
    DECLARE_GLOBAL_DATA_PTR;
    
    static void stm32_sdmmc2_start_data(struct stm32_sdmmc2_priv *priv,
    				    struct mmc_data *data,
    				    struct stm32_sdmmc2_ctx *ctx)
    {
    	u32 data_ctrl, idmabase0;
    
    	/* Configure the SDMMC DPSM (Data Path State Machine) */
    	data_ctrl = (__ilog2(data->blocksize) <<
    		     SDMMC_DCTRL_DBLOCKSIZE_SHIFT) &
    		    SDMMC_DCTRL_DBLOCKSIZE;
    
    	if (data->flags & MMC_DATA_READ) {
    		data_ctrl |= SDMMC_DCTRL_DTDIR;
    		idmabase0 = (u32)data->dest;
    	} else {
    		idmabase0 = (u32)data->src;
    	}
    
    	/* Set the SDMMC Data TimeOut value */
    	writel(SDMMC_CMD_TIMEOUT, priv->base + SDMMC_DTIMER);
    
    	/* Set the SDMMC DataLength value */
    	writel(ctx->data_length, priv->base + SDMMC_DLEN);
    
    	/* Write to SDMMC DCTRL */
    	writel(data_ctrl, priv->base + SDMMC_DCTRL);
    
    	/* Cache align */
    	ctx->cache_start = rounddown(idmabase0, ARCH_DMA_MINALIGN);
    	ctx->cache_end = roundup(idmabase0 + ctx->data_length,
    				 ARCH_DMA_MINALIGN);
    
    	/*
    	 * Flush data cache before DMA start (clean and invalidate)
    	 * Clean also needed for read
    	 * Avoid issue on buffer not cached-aligned
    	 */
    	flush_dcache_range(ctx->cache_start, ctx->cache_end);
    
    	/* Enable internal DMA */
    	writel(idmabase0, priv->base + SDMMC_IDMABASE0);
    	writel(SDMMC_IDMACTRL_IDMAEN, priv->base + SDMMC_IDMACTRL);
    }
    
    static void stm32_sdmmc2_start_cmd(struct stm32_sdmmc2_priv *priv,
    				   struct mmc_cmd *cmd, u32 cmd_param)
    {
    	if (readl(priv->base + SDMMC_ARG) & SDMMC_CMD_CPSMEN)
    		writel(0, priv->base + SDMMC_ARG);
    
    	cmd_param |= cmd->cmdidx | SDMMC_CMD_CPSMEN;
    	if (cmd->resp_type & MMC_RSP_PRESENT) {
    		if (cmd->resp_type & MMC_RSP_136)
    			cmd_param |= SDMMC_CMD_WAITRESP;
    		else if (cmd->resp_type & MMC_RSP_CRC)
    			cmd_param |= SDMMC_CMD_WAITRESP_0;
    		else
    			cmd_param |= SDMMC_CMD_WAITRESP_1;
    	}
    
    	/* Clear flags */
    	writel(SDMMC_ICR_STATIC_FLAGS, priv->base + SDMMC_ICR);
    
    	/* Set SDMMC argument value */
    	writel(cmd->cmdarg, priv->base + SDMMC_ARG);
    
    	/* Set SDMMC command parameters */
    	writel(cmd_param, priv->base + SDMMC_CMD);
    }
    
    static int stm32_sdmmc2_end_cmd(struct stm32_sdmmc2_priv *priv,
    				struct mmc_cmd *cmd,
    				struct stm32_sdmmc2_ctx *ctx)
    {
    	u32 mask = SDMMC_STA_CTIMEOUT;
    	u32 status;
    	int ret;
    
    	if (cmd->resp_type & MMC_RSP_PRESENT) {
    		mask |= SDMMC_STA_CMDREND;
    		if (cmd->resp_type & MMC_RSP_CRC)
    			mask |= SDMMC_STA_CCRCFAIL;
    	} else {
    		mask |= SDMMC_STA_CMDSENT;
    	}
    
    	/* Polling status register */
    	ret = readl_poll_timeout(priv->base + SDMMC_STA, status, status & mask,
    
    
    	if (ret < 0) {
    		debug("%s: timeout reading SDMMC_STA register\n", __func__);
    		ctx->dpsm_abort = true;
    		return ret;
    	}
    
    	/* Check status */
    	if (status & SDMMC_STA_CTIMEOUT) {
    		debug("%s: error SDMMC_STA_CTIMEOUT (0x%x) for cmd %d\n",
    		      __func__, status, cmd->cmdidx);
    		ctx->dpsm_abort = true;
    		return -ETIMEDOUT;
    	}
    
    	if (status & SDMMC_STA_CCRCFAIL && cmd->resp_type & MMC_RSP_CRC) {
    		debug("%s: error SDMMC_STA_CCRCFAIL (0x%x) for cmd %d\n",
    		      __func__, status, cmd->cmdidx);
    		ctx->dpsm_abort = true;
    		return -EILSEQ;
    	}
    
    	if (status & SDMMC_STA_CMDREND && cmd->resp_type & MMC_RSP_PRESENT) {
    		cmd->response[0] = readl(priv->base + SDMMC_RESP1);
    		if (cmd->resp_type & MMC_RSP_136) {
    			cmd->response[1] = readl(priv->base + SDMMC_RESP2);
    			cmd->response[2] = readl(priv->base + SDMMC_RESP3);
    			cmd->response[3] = readl(priv->base + SDMMC_RESP4);
    		}
    	}
    
    	return 0;
    }
    
    static int stm32_sdmmc2_end_data(struct stm32_sdmmc2_priv *priv,
    				 struct mmc_cmd *cmd,
    				 struct mmc_data *data,
    				 struct stm32_sdmmc2_ctx *ctx)
    {
    	u32 mask = SDMMC_STA_DCRCFAIL | SDMMC_STA_DTIMEOUT |
    		   SDMMC_STA_IDMATE | SDMMC_STA_DATAEND;
    	u32 status;
    
    	if (data->flags & MMC_DATA_READ)
    		mask |= SDMMC_STA_RXOVERR;
    	else
    		mask |= SDMMC_STA_TXUNDERR;
    
    	status = readl(priv->base + SDMMC_STA);
    	while (!(status & mask))
    		status = readl(priv->base + SDMMC_STA);
    
    	/*
    	 * Need invalidate the dcache again to avoid any
    	 * cache-refill during the DMA operations (pre-fetching)
    	 */
    	if (data->flags & MMC_DATA_READ)
    		invalidate_dcache_range(ctx->cache_start, ctx->cache_end);
    
    	if (status & SDMMC_STA_DCRCFAIL) {
    		debug("%s: error SDMMC_STA_DCRCFAIL (0x%x) for cmd %d\n",
    		      __func__, status, cmd->cmdidx);
    		if (readl(priv->base + SDMMC_DCOUNT))
    			ctx->dpsm_abort = true;
    		return -EILSEQ;
    	}
    
    	if (status & SDMMC_STA_DTIMEOUT) {
    		debug("%s: error SDMMC_STA_DTIMEOUT (0x%x) for cmd %d\n",
    		      __func__, status, cmd->cmdidx);
    		ctx->dpsm_abort = true;
    		return -ETIMEDOUT;
    	}
    
    	if (status & SDMMC_STA_TXUNDERR) {
    		debug("%s: error SDMMC_STA_TXUNDERR (0x%x) for cmd %d\n",
    		      __func__, status, cmd->cmdidx);
    		ctx->dpsm_abort = true;
    		return -EIO;
    	}
    
    	if (status & SDMMC_STA_RXOVERR) {
    		debug("%s: error SDMMC_STA_RXOVERR (0x%x) for cmd %d\n",
    		      __func__, status, cmd->cmdidx);
    		ctx->dpsm_abort = true;
    		return -EIO;
    	}
    
    	if (status & SDMMC_STA_IDMATE) {
    		debug("%s: error SDMMC_STA_IDMATE (0x%x) for cmd %d\n",
    		      __func__, status, cmd->cmdidx);
    		ctx->dpsm_abort = true;
    		return -EIO;
    	}
    
    	return 0;
    }
    
    static int stm32_sdmmc2_send_cmd(struct udevice *dev, struct mmc_cmd *cmd,
    				 struct mmc_data *data)
    {
    	struct stm32_sdmmc2_priv *priv = dev_get_priv(dev);
    	struct stm32_sdmmc2_ctx ctx;
    	u32 cmdat = data ? SDMMC_CMD_CMDTRANS : 0;
    	int ret, retry = 3;
    
    retry_cmd:
    	ctx.data_length = 0;
    	ctx.dpsm_abort = false;
    
    	if (data) {
    		ctx.data_length = data->blocks * data->blocksize;
    		stm32_sdmmc2_start_data(priv, data, &ctx);
    	}
    
    	stm32_sdmmc2_start_cmd(priv, cmd, cmdat);
    
    	debug("%s: send cmd %d data: 0x%x @ 0x%x\n",
    	      __func__, cmd->cmdidx,
    	      data ? ctx.data_length : 0, (unsigned int)data);
    
    	ret = stm32_sdmmc2_end_cmd(priv, cmd, &ctx);
    
    	if (data && !ret)
    		ret = stm32_sdmmc2_end_data(priv, cmd, data, &ctx);
    
    	/* Clear flags */
    	writel(SDMMC_ICR_STATIC_FLAGS, priv->base + SDMMC_ICR);
    	if (data)
    		writel(0x0, priv->base + SDMMC_IDMACTRL);
    
    	/*
    	 * To stop Data Path State Machine, a stop_transmission command
    	 * shall be send on cmd or data errors.
    	 */
    	if (ctx.dpsm_abort && (cmd->cmdidx != MMC_CMD_STOP_TRANSMISSION)) {
    		struct mmc_cmd stop_cmd;
    
    		stop_cmd.cmdidx = MMC_CMD_STOP_TRANSMISSION;
    		stop_cmd.cmdarg = 0;
    		stop_cmd.resp_type = MMC_RSP_R1b;
    
    		debug("%s: send STOP command to abort dpsm treatments\n",
    		      __func__);
    
    		stm32_sdmmc2_start_cmd(priv, &stop_cmd, SDMMC_CMD_CMDSTOP);
    		stm32_sdmmc2_end_cmd(priv, &stop_cmd, &ctx);
    
    		writel(SDMMC_ICR_STATIC_FLAGS, priv->base + SDMMC_ICR);
    	}
    
    	if ((ret != -ETIMEDOUT) && (ret != 0) && retry) {
    		printf("%s: cmd %d failed, retrying ...\n",
    		       __func__, cmd->cmdidx);
    		retry--;
    		goto retry_cmd;
    	}
    
    	debug("%s: end for CMD %d, ret = %d\n", __func__, cmd->cmdidx, ret);
    
    	return ret;
    }
    
    static void stm32_sdmmc2_pwron(struct stm32_sdmmc2_priv *priv)
    {
    	/* Reset */
    	reset_assert(&priv->reset_ctl);
    	udelay(2);
    	reset_deassert(&priv->reset_ctl);
    
    	udelay(1000);
    
    	/* Set Power State to ON */
    	writel(SDMMC_POWER_PWRCTRL | priv->pwr_reg_msk, priv->base + SDMMC_POWER);
    
    	/*
    	 * 1ms: required power up waiting time before starting the
    	 * SD initialization sequence
    	 */
    	udelay(1000);
    }
    
    #define IS_RISING_EDGE(reg) (reg & SDMMC_CLKCR_NEGEDGE ? 0 : 1)
    static int stm32_sdmmc2_set_ios(struct udevice *dev)
    {
    	struct mmc *mmc = mmc_get_mmc_dev(dev);
    	struct stm32_sdmmc2_priv *priv = dev_get_priv(dev);
    	struct stm32_sdmmc2_plat *plat = dev_get_platdata(dev);
    	struct mmc_config *cfg = &plat->cfg;
    	u32 desired = mmc->clock;
    	u32 sys_clock = clk_get_rate(&priv->clk);
    	u32 clk = 0;
    
    	debug("%s: bus_with = %d, clock = %d\n", __func__,
    	      mmc->bus_width, mmc->clock);
    
    	if ((mmc->bus_width == 1) && (desired == cfg->f_min))
    		stm32_sdmmc2_pwron(priv);
    
    	/*
    	 * clk_div = 0 => command and data generated on SDMMCCLK falling edge
    	 * clk_div > 0 and NEGEDGE = 0 => command and data generated on
    	 * SDMMCCLK rising edge
    	 * clk_div > 0 and NEGEDGE = 1 => command and data generated on
    	 * SDMMCCLK falling edge
    	 */
    	if (desired && ((sys_clock > desired) ||
    			IS_RISING_EDGE(priv->clk_reg_msk))) {
    		clk = DIV_ROUND_UP(sys_clock, 2 * desired);
    		if (clk > SDMMC_CLKCR_CLKDIV_MAX)
    			clk = SDMMC_CLKCR_CLKDIV_MAX;
    	}
    
    	if (mmc->bus_width == 4)
    		clk |= SDMMC_CLKCR_WIDBUS_4;
    	if (mmc->bus_width == 8)
    		clk |= SDMMC_CLKCR_WIDBUS_8;
    
    
    	writel(clk | priv->clk_reg_msk | SDMMC_CLKCR_HWFC_EN,
    	       priv->base + SDMMC_CLKCR);
    
    
    	return 0;
    }
    
    static int stm32_sdmmc2_getcd(struct udevice *dev)
    {
    	struct stm32_sdmmc2_priv *priv = dev_get_priv(dev);
    
    	debug("stm32_sdmmc2_getcd called\n");
    
    	if (dm_gpio_is_valid(&priv->cd_gpio))
    		return dm_gpio_get_value(&priv->cd_gpio);
    
    	return 1;
    }
    
    static const struct dm_mmc_ops stm32_sdmmc2_ops = {
    	.send_cmd = stm32_sdmmc2_send_cmd,
    	.set_ios = stm32_sdmmc2_set_ios,
    	.get_cd = stm32_sdmmc2_getcd,
    };
    
    static int stm32_sdmmc2_probe(struct udevice *dev)
    {
    	struct mmc_uclass_priv *upriv = dev_get_uclass_priv(dev);
    	struct stm32_sdmmc2_plat *plat = dev_get_platdata(dev);
    	struct stm32_sdmmc2_priv *priv = dev_get_priv(dev);
    	struct mmc_config *cfg = &plat->cfg;
    	int ret;
    
    	priv->base = dev_read_addr(dev);
    	if (priv->base == FDT_ADDR_T_NONE)
    		return -EINVAL;
    
    	if (dev_read_bool(dev, "st,negedge"))
    		priv->clk_reg_msk |= SDMMC_CLKCR_NEGEDGE;
    	if (dev_read_bool(dev, "st,dirpol"))
    		priv->pwr_reg_msk |= SDMMC_POWER_DIRPOL;
    
    	if (dev_read_bool(dev, "st,pin-ckin"))
    		priv->clk_reg_msk |= SDMMC_CLKCR_SELCLKRX_CKIN;
    
    
    	ret = clk_get_by_index(dev, 0, &priv->clk);
    	if (ret)
    		return ret;
    
    	ret = clk_enable(&priv->clk);
    	if (ret)
    		goto clk_free;
    
    	ret = reset_get_by_index(dev, 0, &priv->reset_ctl);
    	if (ret)
    		goto clk_disable;
    
    	gpio_request_by_name(dev, "cd-gpios", 0, &priv->cd_gpio,
    			     GPIOD_IS_IN);
    
    	cfg->f_min = 400000;
    	cfg->f_max = dev_read_u32_default(dev, "max-frequency", 52000000);
    	cfg->voltages = MMC_VDD_32_33 | MMC_VDD_33_34 | MMC_VDD_165_195;
    	cfg->b_max = CONFIG_SYS_MMC_MAX_BLK_COUNT;
    	cfg->name = "STM32 SDMMC2";
    
    	cfg->host_caps = 0;
    	if (cfg->f_max > 25000000)
    		cfg->host_caps |= MMC_MODE_HS_52MHz | MMC_MODE_HS;
    
    	switch (dev_read_u32_default(dev, "bus-width", 1)) {
    	case 8:
    		cfg->host_caps |= MMC_MODE_8BIT;
    	case 4:
    		cfg->host_caps |= MMC_MODE_4BIT;
    		break;
    	case 1:
    		break;
    	default:
    
    		pr_err("invalid \"bus-width\" property, force to 1\n");
    
    	}
    
    	upriv->mmc = &plat->mmc;
    
    	return 0;
    
    clk_disable:
    	clk_disable(&priv->clk);
    clk_free:
    	clk_free(&priv->clk);
    
    	return ret;
    }
    
    int stm32_sdmmc_bind(struct udevice *dev)
    {
    	struct stm32_sdmmc2_plat *plat = dev_get_platdata(dev);
    
    	return mmc_bind(dev, &plat->mmc, &plat->cfg);
    }
    
    static const struct udevice_id stm32_sdmmc2_ids[] = {
    	{ .compatible = "st,stm32-sdmmc2" },
    	{ }
    };
    
    U_BOOT_DRIVER(stm32_sdmmc2) = {
    	.name = "stm32_sdmmc2",
    	.id = UCLASS_MMC,
    	.of_match = stm32_sdmmc2_ids,
    	.ops = &stm32_sdmmc2_ops,
    	.probe = stm32_sdmmc2_probe,
    	.bind = stm32_sdmmc_bind,
    	.priv_auto_alloc_size = sizeof(struct stm32_sdmmc2_priv),
    	.platdata_auto_alloc_size = sizeof(struct stm32_sdmmc2_plat),
    };