drivers/mmc/host/sdhci-st.c - linux-imx - Git at Google

 /*
  * Support for SDHCI on STMicroelectronics SoCs
  *
  * Copyright (C) 2014 STMicroelectronics Ltd
  * Author: Giuseppe Cavallaro <peppe.cavallaro@st.com>
  * Contributors: Peter Griffin <peter.griffin@linaro.org>
  *
  * Based on sdhci-cns3xxx.c
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 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.
  *
  */

 #include <linux/io.h>
 #include <linux/of.h>
 #include <linux/module.h>
 #include <linux/err.h>
 #include <linux/mmc/host.h>
 #include <linux/reset.h>
 #include "sdhci-pltfm.h"

 struct st_mmc_platform_data {
 	struct  reset_control *rstc;
 	struct  clk *icnclk;
 	void __iomem *top_ioaddr;
 };

 /* MMCSS glue logic to setup the HC on some ST SoCs (e.g. STiH407 family) */

 #define ST_MMC_CCONFIG_REG_1		0x400
 #define ST_MMC_CCONFIG_TIMEOUT_CLK_UNIT	BIT(24)
 #define ST_MMC_CCONFIG_TIMEOUT_CLK_FREQ	BIT(12)
 #define ST_MMC_CCONFIG_TUNING_COUNT_DEFAULT	BIT(8)
 #define ST_MMC_CCONFIG_ASYNC_WAKEUP	BIT(0)
 #define ST_MMC_CCONFIG_1_DEFAULT	\
 				((ST_MMC_CCONFIG_TIMEOUT_CLK_UNIT) | \
 				 (ST_MMC_CCONFIG_TIMEOUT_CLK_FREQ) | \
 				 (ST_MMC_CCONFIG_TUNING_COUNT_DEFAULT))

 #define ST_MMC_CCONFIG_REG_2		0x404
 #define ST_MMC_CCONFIG_HIGH_SPEED	BIT(28)
 #define ST_MMC_CCONFIG_ADMA2		BIT(24)
 #define ST_MMC_CCONFIG_8BIT		BIT(20)
 #define ST_MMC_CCONFIG_MAX_BLK_LEN	16
 #define  MAX_BLK_LEN_1024		1
 #define  MAX_BLK_LEN_2048		2
 #define BASE_CLK_FREQ_200		0xc8
 #define BASE_CLK_FREQ_100		0x64
 #define BASE_CLK_FREQ_50		0x32
 #define ST_MMC_CCONFIG_2_DEFAULT \
 	(ST_MMC_CCONFIG_HIGH_SPEED | ST_MMC_CCONFIG_ADMA2 | \
 	 ST_MMC_CCONFIG_8BIT | \
 	 (MAX_BLK_LEN_1024 << ST_MMC_CCONFIG_MAX_BLK_LEN))

 #define ST_MMC_CCONFIG_REG_3			0x408
 #define ST_MMC_CCONFIG_EMMC_SLOT_TYPE		BIT(28)
 #define ST_MMC_CCONFIG_64BIT			BIT(24)
 #define ST_MMC_CCONFIG_ASYNCH_INTR_SUPPORT	BIT(20)
 #define ST_MMC_CCONFIG_1P8_VOLT			BIT(16)
 #define ST_MMC_CCONFIG_3P0_VOLT			BIT(12)
 #define ST_MMC_CCONFIG_3P3_VOLT			BIT(8)
 #define ST_MMC_CCONFIG_SUSP_RES_SUPPORT		BIT(4)
 #define ST_MMC_CCONFIG_SDMA			BIT(0)
 #define ST_MMC_CCONFIG_3_DEFAULT	\
 			 (ST_MMC_CCONFIG_ASYNCH_INTR_SUPPORT	| \
 			  ST_MMC_CCONFIG_3P3_VOLT		| \
 			  ST_MMC_CCONFIG_SUSP_RES_SUPPORT	| \
 			  ST_MMC_CCONFIG_SDMA)

 #define ST_MMC_CCONFIG_REG_4	0x40c
 #define ST_MMC_CCONFIG_D_DRIVER	BIT(20)
 #define ST_MMC_CCONFIG_C_DRIVER	BIT(16)
 #define ST_MMC_CCONFIG_A_DRIVER	BIT(12)
 #define ST_MMC_CCONFIG_DDR50	BIT(8)
 #define ST_MMC_CCONFIG_SDR104	BIT(4)
 #define ST_MMC_CCONFIG_SDR50	BIT(0)
 #define ST_MMC_CCONFIG_4_DEFAULT	0

 #define ST_MMC_CCONFIG_REG_5		0x410
 #define ST_MMC_CCONFIG_TUNING_FOR_SDR50	BIT(8)
 #define RETUNING_TIMER_CNT_MAX		0xf
 #define ST_MMC_CCONFIG_5_DEFAULT	0

 /* I/O configuration for Arasan IP */
 #define ST_MMC_GP_OUTPUT	0x450
 #define ST_MMC_GP_OUTPUT_CD	BIT(12)

 #define ST_MMC_STATUS_R		0x460

 #define ST_TOP_MMC_DLY_FIX_OFF(x)	(x - 0x8)

 /* TOP config registers to manage static and dynamic delay */
 #define ST_TOP_MMC_TX_CLK_DLY			ST_TOP_MMC_DLY_FIX_OFF(0x8)
 #define ST_TOP_MMC_RX_CLK_DLY			ST_TOP_MMC_DLY_FIX_OFF(0xc)
 /* MMC delay control register */
 #define ST_TOP_MMC_DLY_CTRL			ST_TOP_MMC_DLY_FIX_OFF(0x18)
 #define ST_TOP_MMC_DLY_CTRL_DLL_BYPASS_CMD	BIT(0)
 #define ST_TOP_MMC_DLY_CTRL_DLL_BYPASS_PH_SEL	BIT(1)
 #define ST_TOP_MMC_DLY_CTRL_TX_DLL_ENABLE	BIT(8)
 #define ST_TOP_MMC_DLY_CTRL_RX_DLL_ENABLE	BIT(9)
 #define ST_TOP_MMC_DLY_CTRL_ATUNE_NOT_CFG_DLY	BIT(10)
 #define ST_TOP_MMC_START_DLL_LOCK		BIT(11)

 /* register to provide the phase-shift value for DLL */
 #define ST_TOP_MMC_TX_DLL_STEP_DLY		ST_TOP_MMC_DLY_FIX_OFF(0x1c)
 #define ST_TOP_MMC_RX_DLL_STEP_DLY		ST_TOP_MMC_DLY_FIX_OFF(0x20)
 #define ST_TOP_MMC_RX_CMD_STEP_DLY		ST_TOP_MMC_DLY_FIX_OFF(0x24)

 /* phase shift delay on the tx clk 2.188ns */
 #define ST_TOP_MMC_TX_DLL_STEP_DLY_VALID	0x6

 #define ST_TOP_MMC_DLY_MAX			0xf

 #define ST_TOP_MMC_DYN_DLY_CONF	\
 		(ST_TOP_MMC_DLY_CTRL_TX_DLL_ENABLE | \
 		 ST_TOP_MMC_DLY_CTRL_ATUNE_NOT_CFG_DLY | \
 		 ST_TOP_MMC_START_DLL_LOCK)

 /*
  * For clock speeds greater than 90MHz, we need to check that the
  * DLL procedure has finished before switching to ultra-speed modes.
  */
 #define	CLK_TO_CHECK_DLL_LOCK	90000000

 static inline void st_mmcss_set_static_delay(void __iomem *ioaddr)
 {
 	if (!ioaddr)
 		return;

 	writel_relaxed(0x0, ioaddr + ST_TOP_MMC_DLY_CTRL);
 	writel_relaxed(ST_TOP_MMC_DLY_MAX,
 			ioaddr + ST_TOP_MMC_TX_CLK_DLY);
 }

 /**
  * st_mmcss_cconfig: configure the Arasan HC inside the flashSS.
  * @np: dt device node.
  * @host: sdhci host
  * Description: this function is to configure the Arasan host controller.
  * On some ST SoCs, i.e. STiH407 family, the MMC devices inside a dedicated
  * flashSS sub-system which needs to be configured to be compliant to eMMC 4.5
  * or eMMC4.3.  This has to be done before registering the sdhci host.
  */
 static void st_mmcss_cconfig(struct device_node *np, struct sdhci_host *host)
 {
 	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
 	struct mmc_host *mhost = host->mmc;
 	u32 cconf2, cconf3, cconf4, cconf5;

 	if (!of_device_is_compatible(np, "st,sdhci-stih407"))
 		return;

 	cconf2 = ST_MMC_CCONFIG_2_DEFAULT;
 	cconf3 = ST_MMC_CCONFIG_3_DEFAULT;
 	cconf4 = ST_MMC_CCONFIG_4_DEFAULT;
 	cconf5 = ST_MMC_CCONFIG_5_DEFAULT;

 	writel_relaxed(ST_MMC_CCONFIG_1_DEFAULT,
 			host->ioaddr + ST_MMC_CCONFIG_REG_1);

 	/* Set clock frequency, default to 50MHz if max-frequency is not
 	 * provided */

 	switch (mhost->f_max) {
 	case 200000000:
 		clk_set_rate(pltfm_host->clk, mhost->f_max);
 		cconf2 |= BASE_CLK_FREQ_200;
 		break;
 	case 100000000:
 		clk_set_rate(pltfm_host->clk, mhost->f_max);
 		cconf2 |= BASE_CLK_FREQ_100;
 		break;
 	default:
 		clk_set_rate(pltfm_host->clk, 50000000);
 		cconf2 |= BASE_CLK_FREQ_50;
 	}

 	writel_relaxed(cconf2, host->ioaddr + ST_MMC_CCONFIG_REG_2);

 	if (!mmc_card_is_removable(mhost))
 		cconf3 |= ST_MMC_CCONFIG_EMMC_SLOT_TYPE;
 	else
 		/* CARD _D ET_CTRL */
 		writel_relaxed(ST_MMC_GP_OUTPUT_CD,
 				host->ioaddr + ST_MMC_GP_OUTPUT);

 	if (mhost->caps & MMC_CAP_UHS_SDR50) {
 		/* use 1.8V */
 		cconf3 |= ST_MMC_CCONFIG_1P8_VOLT;
 		cconf4 |= ST_MMC_CCONFIG_SDR50;
 		/* Use tuning */
 		cconf5 |= ST_MMC_CCONFIG_TUNING_FOR_SDR50;
 		/* Max timeout for retuning */
 		cconf5 |= RETUNING_TIMER_CNT_MAX;
 	}

 	if (mhost->caps & MMC_CAP_UHS_SDR104) {
 		/*
 		 * SDR104 implies the HC can support HS200 mode, so
 		 * it's mandatory to use 1.8V
 		 */
 		cconf3 |= ST_MMC_CCONFIG_1P8_VOLT;
 		cconf4 |= ST_MMC_CCONFIG_SDR104;
 		/* Max timeout for retuning */
 		cconf5 |= RETUNING_TIMER_CNT_MAX;
 	}

 	if (mhost->caps & MMC_CAP_UHS_DDR50)
 		cconf4 |= ST_MMC_CCONFIG_DDR50;

 	writel_relaxed(cconf3, host->ioaddr + ST_MMC_CCONFIG_REG_3);
 	writel_relaxed(cconf4, host->ioaddr + ST_MMC_CCONFIG_REG_4);
 	writel_relaxed(cconf5, host->ioaddr + ST_MMC_CCONFIG_REG_5);
 }

 static inline void st_mmcss_set_dll(void __iomem *ioaddr)
 {
 	if (!ioaddr)
 		return;

 	writel_relaxed(ST_TOP_MMC_DYN_DLY_CONF,	ioaddr + ST_TOP_MMC_DLY_CTRL);
 	writel_relaxed(ST_TOP_MMC_TX_DLL_STEP_DLY_VALID,
 			ioaddr + ST_TOP_MMC_TX_DLL_STEP_DLY);
 }

 static int st_mmcss_lock_dll(void __iomem *ioaddr)
 {
 	unsigned long curr, value;
 	unsigned long finish = jiffies + HZ;

 	/* Checks if the DLL procedure is finished */
 	do {
 		curr = jiffies;
 		value = readl(ioaddr + ST_MMC_STATUS_R);
 		if (value & 0x1)
 			return 0;

 		cpu_relax();
 	} while (!time_after_eq(curr, finish));

 	return -EBUSY;
 }

 static int sdhci_st_set_dll_for_clock(struct sdhci_host *host)
 {
 	int ret = 0;
 	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
 	struct st_mmc_platform_data *pdata = sdhci_pltfm_priv(pltfm_host);

 	if (host->clock > CLK_TO_CHECK_DLL_LOCK) {
 		st_mmcss_set_dll(pdata->top_ioaddr);
 		ret = st_mmcss_lock_dll(host->ioaddr);
 	}

 	return ret;
 }

 static void sdhci_st_set_uhs_signaling(struct sdhci_host *host,
 					unsigned int uhs)
 {
 	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
 	struct st_mmc_platform_data *pdata = sdhci_pltfm_priv(pltfm_host);
 	u16 ctrl_2 = sdhci_readw(host, SDHCI_HOST_CONTROL2);
 	int ret = 0;

 	/* Select Bus Speed Mode for host */
 	ctrl_2 &= ~SDHCI_CTRL_UHS_MASK;
 	switch (uhs) {
 	/*
 	 * Set V18_EN -- UHS modes do not work without this.
 	 * does not change signaling voltage
 	 */

 	case MMC_TIMING_UHS_SDR12:
 		st_mmcss_set_static_delay(pdata->top_ioaddr);
 		ctrl_2 |= SDHCI_CTRL_UHS_SDR12 | SDHCI_CTRL_VDD_180;
 		break;
 	case MMC_TIMING_UHS_SDR25:
 		st_mmcss_set_static_delay(pdata->top_ioaddr);
 		ctrl_2 |= SDHCI_CTRL_UHS_SDR25 | SDHCI_CTRL_VDD_180;
 		break;
 	case MMC_TIMING_UHS_SDR50:
 		st_mmcss_set_static_delay(pdata->top_ioaddr);
 		ctrl_2 |= SDHCI_CTRL_UHS_SDR50 | SDHCI_CTRL_VDD_180;
 		ret = sdhci_st_set_dll_for_clock(host);
 		break;
 	case MMC_TIMING_UHS_SDR104:
 	case MMC_TIMING_MMC_HS200:
 		st_mmcss_set_static_delay(pdata->top_ioaddr);
 		ctrl_2 |= SDHCI_CTRL_UHS_SDR104 | SDHCI_CTRL_VDD_180;
 		ret =  sdhci_st_set_dll_for_clock(host);
 		break;
 	case MMC_TIMING_UHS_DDR50:
 	case MMC_TIMING_MMC_DDR52:
 		st_mmcss_set_static_delay(pdata->top_ioaddr);
 		ctrl_2 |= SDHCI_CTRL_UHS_DDR50 | SDHCI_CTRL_VDD_180;
 		break;
 	}

 	if (ret)
 		dev_warn(mmc_dev(host->mmc), "Error setting dll for clock "
 						"(uhs %d)\n", uhs);

 	dev_dbg(mmc_dev(host->mmc), "uhs %d, ctrl_2 %04X\n", uhs, ctrl_2);

 	sdhci_writew(host, ctrl_2, SDHCI_HOST_CONTROL2);
 }

 static u32 sdhci_st_readl(struct sdhci_host *host, int reg)
 {
 	u32 ret;

 	switch (reg) {
 	case SDHCI_CAPABILITIES:
 		ret = readl_relaxed(host->ioaddr + reg);
 		/* Support 3.3V and 1.8V */
 		ret &= ~SDHCI_CAN_VDD_300;
 		break;
 	default:
 		ret = readl_relaxed(host->ioaddr + reg);
 	}
 	return ret;
 }

 static const struct sdhci_ops sdhci_st_ops = {
 	.get_max_clock = sdhci_pltfm_clk_get_max_clock,
 	.set_clock = sdhci_set_clock,
 	.set_bus_width = sdhci_set_bus_width,
 	.read_l = sdhci_st_readl,
 	.reset = sdhci_reset,
 	.set_uhs_signaling = sdhci_st_set_uhs_signaling,
 };

 static const struct sdhci_pltfm_data sdhci_st_pdata = {
 	.ops = &sdhci_st_ops,
 	.quirks = SDHCI_QUIRK_NO_ENDATTR_IN_NOPDESC |
 		SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN |
 		SDHCI_QUIRK_NO_HISPD_BIT,
 	.quirks2 = SDHCI_QUIRK2_PRESET_VALUE_BROKEN |
 		SDHCI_QUIRK2_STOP_WITH_TC,
 };


 static int sdhci_st_probe(struct platform_device *pdev)
 {
 	struct device_node *np = pdev->dev.of_node;
 	struct sdhci_host *host;
 	struct st_mmc_platform_data *pdata;
 	struct sdhci_pltfm_host *pltfm_host;
 	struct clk *clk, *icnclk;
 	int ret = 0;
 	u16 host_version;
 	struct resource *res;
 	struct reset_control *rstc;

 	clk =  devm_clk_get(&pdev->dev, "mmc");
 	if (IS_ERR(clk)) {
 		dev_err(&pdev->dev, "Peripheral clk not found\n");
 		return PTR_ERR(clk);
 	}

 	/* ICN clock isn't compulsory, but use it if it's provided. */
 	icnclk = devm_clk_get(&pdev->dev, "icn");
 	if (IS_ERR(icnclk))
 		icnclk = NULL;

 	rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
 	if (IS_ERR(rstc))
 		rstc = NULL;
 	else
 		reset_control_deassert(rstc);

 	host = sdhci_pltfm_init(pdev, &sdhci_st_pdata, sizeof(*pdata));
 	if (IS_ERR(host)) {
 		dev_err(&pdev->dev, "Failed sdhci_pltfm_init\n");
 		ret = PTR_ERR(host);
 		goto err_pltfm_init;
 	}

 	pltfm_host = sdhci_priv(host);
 	pdata = sdhci_pltfm_priv(pltfm_host);
 	pdata->rstc = rstc;

 	ret = mmc_of_parse(host->mmc);
 	if (ret) {
 		dev_err(&pdev->dev, "Failed mmc_of_parse\n");
 		goto err_of;
 	}

 	ret = clk_prepare_enable(clk);
 	if (ret) {
 		dev_err(&pdev->dev, "Failed to prepare clock\n");
 		goto err_of;
 	}

 	ret = clk_prepare_enable(icnclk);
 	if (ret) {
 		dev_err(&pdev->dev, "Failed to prepare icn clock\n");
 		goto err_icnclk;
 	}

 	/* Configure the FlashSS Top registers for setting eMMC TX/RX delay */
 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
 					   "top-mmc-delay");
 	pdata->top_ioaddr = devm_ioremap_resource(&pdev->dev, res);
 	if (IS_ERR(pdata->top_ioaddr)) {
 		dev_warn(&pdev->dev, "FlashSS Top Dly registers not available");
 		pdata->top_ioaddr = NULL;
 	}

 	pltfm_host->clk = clk;
 	pdata->icnclk = icnclk;

 	/* Configure the Arasan HC inside the flashSS */
 	st_mmcss_cconfig(np, host);

 	ret = sdhci_add_host(host);
 	if (ret) {
 		dev_err(&pdev->dev, "Failed sdhci_add_host\n");
 		goto err_out;
 	}

 	host_version = readw_relaxed((host->ioaddr + SDHCI_HOST_VERSION));

 	dev_info(&pdev->dev, "SDHCI ST Initialised: Host Version: 0x%x Vendor Version 0x%x\n",
 		((host_version & SDHCI_SPEC_VER_MASK) >> SDHCI_SPEC_VER_SHIFT),
 		((host_version & SDHCI_VENDOR_VER_MASK) >>
 		SDHCI_VENDOR_VER_SHIFT));

 	return 0;

 err_out:
 	clk_disable_unprepare(icnclk);
 err_icnclk:
 	clk_disable_unprepare(clk);
 err_of:
 	sdhci_pltfm_free(pdev);
 err_pltfm_init:
 	if (rstc)
 		reset_control_assert(rstc);

 	return ret;
 }

 static int sdhci_st_remove(struct platform_device *pdev)
 {
 	struct sdhci_host *host = platform_get_drvdata(pdev);
 	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
 	struct st_mmc_platform_data *pdata = sdhci_pltfm_priv(pltfm_host);
 	struct reset_control *rstc = pdata->rstc;
 	int ret;

 	ret = sdhci_pltfm_unregister(pdev);

 	clk_disable_unprepare(pdata->icnclk);

 	if (rstc)
 		reset_control_assert(rstc);

 	return ret;
 }

 #ifdef CONFIG_PM_SLEEP
 static int sdhci_st_suspend(struct device *dev)
 {
 	struct sdhci_host *host = dev_get_drvdata(dev);
 	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
 	struct st_mmc_platform_data *pdata = sdhci_pltfm_priv(pltfm_host);
 	int ret;

 	if (host->tuning_mode != SDHCI_TUNING_MODE_3)
 		mmc_retune_needed(host->mmc);

 	ret = sdhci_suspend_host(host);
 	if (ret)
 		goto out;

 	if (pdata->rstc)
 		reset_control_assert(pdata->rstc);

 	clk_disable_unprepare(pdata->icnclk);
 	clk_disable_unprepare(pltfm_host->clk);
 out:
 	return ret;
 }

 static int sdhci_st_resume(struct device *dev)
 {
 	struct sdhci_host *host = dev_get_drvdata(dev);
 	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
 	struct st_mmc_platform_data *pdata = sdhci_pltfm_priv(pltfm_host);
 	struct device_node *np = dev->of_node;
 	int ret;

 	ret = clk_prepare_enable(pltfm_host->clk);
 	if (ret)
 		return ret;

 	ret = clk_prepare_enable(pdata->icnclk);
 	if (ret) {
 		clk_disable_unprepare(pltfm_host->clk);
 		return ret;
 	}

 	if (pdata->rstc)
 		reset_control_deassert(pdata->rstc);

 	st_mmcss_cconfig(np, host);

 	return sdhci_resume_host(host);
 }
 #endif

 static SIMPLE_DEV_PM_OPS(sdhci_st_pmops, sdhci_st_suspend, sdhci_st_resume);

 static const struct of_device_id st_sdhci_match[] = {
 	{ .compatible = "st,sdhci" },
 	{},
 };

 MODULE_DEVICE_TABLE(of, st_sdhci_match);

 static struct platform_driver sdhci_st_driver = {
 	.probe = sdhci_st_probe,
 	.remove = sdhci_st_remove,
 	.driver = {
 		   .name = "sdhci-st",
 		   .pm = &sdhci_st_pmops,
 		   .of_match_table = of_match_ptr(st_sdhci_match),
 		  },
 };

 module_platform_driver(sdhci_st_driver);

 MODULE_DESCRIPTION("SDHCI driver for STMicroelectronics SoCs");
 MODULE_AUTHOR("Giuseppe Cavallaro <peppe.cavallaro@st.com>");
 MODULE_LICENSE("GPL v2");
 MODULE_ALIAS("platform:sdhci-st");
	/*
	* Support for SDHCI on STMicroelectronics SoCs
	*
	* Copyright (C) 2014 STMicroelectronics Ltd
	* Author: Giuseppe Cavallaro <peppe.cavallaro@st.com>
	* Contributors: Peter Griffin <peter.griffin@linaro.org>
	*
	* Based on sdhci-cns3xxx.c
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 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.
	*
	*/

	#include <linux/io.h>
	#include <linux/of.h>
	#include <linux/module.h>
	#include <linux/err.h>
	#include <linux/mmc/host.h>
	#include <linux/reset.h>
	#include "sdhci-pltfm.h"

	struct st_mmc_platform_data {
	struct reset_control *rstc;
	struct clk *icnclk;
	void __iomem *top_ioaddr;
	};

	/* MMCSS glue logic to setup the HC on some ST SoCs (e.g. STiH407 family) */

	#define ST_MMC_CCONFIG_REG_1 0x400
	#define ST_MMC_CCONFIG_TIMEOUT_CLK_UNIT BIT(24)
	#define ST_MMC_CCONFIG_TIMEOUT_CLK_FREQ BIT(12)
	#define ST_MMC_CCONFIG_TUNING_COUNT_DEFAULT BIT(8)
	#define ST_MMC_CCONFIG_ASYNC_WAKEUP BIT(0)
	#define ST_MMC_CCONFIG_1_DEFAULT \
	((ST_MMC_CCONFIG_TIMEOUT_CLK_UNIT) \| \
	(ST_MMC_CCONFIG_TIMEOUT_CLK_FREQ) \| \
	(ST_MMC_CCONFIG_TUNING_COUNT_DEFAULT))

	#define ST_MMC_CCONFIG_REG_2 0x404
	#define ST_MMC_CCONFIG_HIGH_SPEED BIT(28)
	#define ST_MMC_CCONFIG_ADMA2 BIT(24)
	#define ST_MMC_CCONFIG_8BIT BIT(20)
	#define ST_MMC_CCONFIG_MAX_BLK_LEN 16
	#define MAX_BLK_LEN_1024 1
	#define MAX_BLK_LEN_2048 2
	#define BASE_CLK_FREQ_200 0xc8
	#define BASE_CLK_FREQ_100 0x64
	#define BASE_CLK_FREQ_50 0x32
	#define ST_MMC_CCONFIG_2_DEFAULT \
	(ST_MMC_CCONFIG_HIGH_SPEED \| ST_MMC_CCONFIG_ADMA2 \| \
	ST_MMC_CCONFIG_8BIT \| \
	(MAX_BLK_LEN_1024 << ST_MMC_CCONFIG_MAX_BLK_LEN))

	#define ST_MMC_CCONFIG_REG_3 0x408
	#define ST_MMC_CCONFIG_EMMC_SLOT_TYPE BIT(28)
	#define ST_MMC_CCONFIG_64BIT BIT(24)
	#define ST_MMC_CCONFIG_ASYNCH_INTR_SUPPORT BIT(20)
	#define ST_MMC_CCONFIG_1P8_VOLT BIT(16)
	#define ST_MMC_CCONFIG_3P0_VOLT BIT(12)
	#define ST_MMC_CCONFIG_3P3_VOLT BIT(8)
	#define ST_MMC_CCONFIG_SUSP_RES_SUPPORT BIT(4)
	#define ST_MMC_CCONFIG_SDMA BIT(0)
	#define ST_MMC_CCONFIG_3_DEFAULT \
	(ST_MMC_CCONFIG_ASYNCH_INTR_SUPPORT \| \
	ST_MMC_CCONFIG_3P3_VOLT \| \
	ST_MMC_CCONFIG_SUSP_RES_SUPPORT \| \
	ST_MMC_CCONFIG_SDMA)

	#define ST_MMC_CCONFIG_REG_4 0x40c
	#define ST_MMC_CCONFIG_D_DRIVER BIT(20)
	#define ST_MMC_CCONFIG_C_DRIVER BIT(16)
	#define ST_MMC_CCONFIG_A_DRIVER BIT(12)
	#define ST_MMC_CCONFIG_DDR50 BIT(8)
	#define ST_MMC_CCONFIG_SDR104 BIT(4)
	#define ST_MMC_CCONFIG_SDR50 BIT(0)
	#define ST_MMC_CCONFIG_4_DEFAULT 0

	#define ST_MMC_CCONFIG_REG_5 0x410
	#define ST_MMC_CCONFIG_TUNING_FOR_SDR50 BIT(8)
	#define RETUNING_TIMER_CNT_MAX 0xf
	#define ST_MMC_CCONFIG_5_DEFAULT 0

	/* I/O configuration for Arasan IP */
	#define ST_MMC_GP_OUTPUT 0x450
	#define ST_MMC_GP_OUTPUT_CD BIT(12)

	#define ST_MMC_STATUS_R 0x460

	#define ST_TOP_MMC_DLY_FIX_OFF(x) (x - 0x8)

	/* TOP config registers to manage static and dynamic delay */
	#define ST_TOP_MMC_TX_CLK_DLY ST_TOP_MMC_DLY_FIX_OFF(0x8)
	#define ST_TOP_MMC_RX_CLK_DLY ST_TOP_MMC_DLY_FIX_OFF(0xc)
	/* MMC delay control register */
	#define ST_TOP_MMC_DLY_CTRL ST_TOP_MMC_DLY_FIX_OFF(0x18)
	#define ST_TOP_MMC_DLY_CTRL_DLL_BYPASS_CMD BIT(0)
	#define ST_TOP_MMC_DLY_CTRL_DLL_BYPASS_PH_SEL BIT(1)
	#define ST_TOP_MMC_DLY_CTRL_TX_DLL_ENABLE BIT(8)
	#define ST_TOP_MMC_DLY_CTRL_RX_DLL_ENABLE BIT(9)
	#define ST_TOP_MMC_DLY_CTRL_ATUNE_NOT_CFG_DLY BIT(10)
	#define ST_TOP_MMC_START_DLL_LOCK BIT(11)

	/* register to provide the phase-shift value for DLL */
	#define ST_TOP_MMC_TX_DLL_STEP_DLY ST_TOP_MMC_DLY_FIX_OFF(0x1c)
	#define ST_TOP_MMC_RX_DLL_STEP_DLY ST_TOP_MMC_DLY_FIX_OFF(0x20)
	#define ST_TOP_MMC_RX_CMD_STEP_DLY ST_TOP_MMC_DLY_FIX_OFF(0x24)

	/* phase shift delay on the tx clk 2.188ns */
	#define ST_TOP_MMC_TX_DLL_STEP_DLY_VALID 0x6

	#define ST_TOP_MMC_DLY_MAX 0xf

	#define ST_TOP_MMC_DYN_DLY_CONF \
	(ST_TOP_MMC_DLY_CTRL_TX_DLL_ENABLE \| \
	ST_TOP_MMC_DLY_CTRL_ATUNE_NOT_CFG_DLY \| \
	ST_TOP_MMC_START_DLL_LOCK)

	/*
	* For clock speeds greater than 90MHz, we need to check that the
	* DLL procedure has finished before switching to ultra-speed modes.
	*/
	#define CLK_TO_CHECK_DLL_LOCK 90000000

	static inline void st_mmcss_set_static_delay(void __iomem *ioaddr)
	{
	if (!ioaddr)
	return;

	writel_relaxed(0x0, ioaddr + ST_TOP_MMC_DLY_CTRL);
	writel_relaxed(ST_TOP_MMC_DLY_MAX,
	ioaddr + ST_TOP_MMC_TX_CLK_DLY);
	}

	/**
	* st_mmcss_cconfig: configure the Arasan HC inside the flashSS.
	* @np: dt device node.
	* @host: sdhci host
	* Description: this function is to configure the Arasan host controller.
	* On some ST SoCs, i.e. STiH407 family, the MMC devices inside a dedicated
	* flashSS sub-system which needs to be configured to be compliant to eMMC 4.5
	* or eMMC4.3. This has to be done before registering the sdhci host.
	*/
	static void st_mmcss_cconfig(struct device_node np, struct sdhci_host host)
	{
	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
	struct mmc_host *mhost = host->mmc;
	u32 cconf2, cconf3, cconf4, cconf5;

	if (!of_device_is_compatible(np, "st,sdhci-stih407"))
	return;

	cconf2 = ST_MMC_CCONFIG_2_DEFAULT;
	cconf3 = ST_MMC_CCONFIG_3_DEFAULT;
	cconf4 = ST_MMC_CCONFIG_4_DEFAULT;
	cconf5 = ST_MMC_CCONFIG_5_DEFAULT;

	writel_relaxed(ST_MMC_CCONFIG_1_DEFAULT,
	host->ioaddr + ST_MMC_CCONFIG_REG_1);

	/* Set clock frequency, default to 50MHz if max-frequency is not
	* provided */

	switch (mhost->f_max) {
	case 200000000:
	clk_set_rate(pltfm_host->clk, mhost->f_max);
	cconf2 \|= BASE_CLK_FREQ_200;
	break;
	case 100000000:
	clk_set_rate(pltfm_host->clk, mhost->f_max);
	cconf2 \|= BASE_CLK_FREQ_100;
	break;
	default:
	clk_set_rate(pltfm_host->clk, 50000000);
	cconf2 \|= BASE_CLK_FREQ_50;
	}

	writel_relaxed(cconf2, host->ioaddr + ST_MMC_CCONFIG_REG_2);

	if (!mmc_card_is_removable(mhost))
	cconf3 \|= ST_MMC_CCONFIG_EMMC_SLOT_TYPE;
	else
	/* CARD _D ET_CTRL */
	writel_relaxed(ST_MMC_GP_OUTPUT_CD,
	host->ioaddr + ST_MMC_GP_OUTPUT);

	if (mhost->caps & MMC_CAP_UHS_SDR50) {
	/* use 1.8V */
	cconf3 \|= ST_MMC_CCONFIG_1P8_VOLT;
	cconf4 \|= ST_MMC_CCONFIG_SDR50;
	/* Use tuning */
	cconf5 \|= ST_MMC_CCONFIG_TUNING_FOR_SDR50;
	/* Max timeout for retuning */
	cconf5 \|= RETUNING_TIMER_CNT_MAX;
	}

	if (mhost->caps & MMC_CAP_UHS_SDR104) {
	/*
	* SDR104 implies the HC can support HS200 mode, so
	* it's mandatory to use 1.8V
	*/
	cconf3 \|= ST_MMC_CCONFIG_1P8_VOLT;
	cconf4 \|= ST_MMC_CCONFIG_SDR104;
	/* Max timeout for retuning */
	cconf5 \|= RETUNING_TIMER_CNT_MAX;
	}

	if (mhost->caps & MMC_CAP_UHS_DDR50)
	cconf4 \|= ST_MMC_CCONFIG_DDR50;

	writel_relaxed(cconf3, host->ioaddr + ST_MMC_CCONFIG_REG_3);
	writel_relaxed(cconf4, host->ioaddr + ST_MMC_CCONFIG_REG_4);
	writel_relaxed(cconf5, host->ioaddr + ST_MMC_CCONFIG_REG_5);
	}

	static inline void st_mmcss_set_dll(void __iomem *ioaddr)
	{
	if (!ioaddr)
	return;

	writel_relaxed(ST_TOP_MMC_DYN_DLY_CONF, ioaddr + ST_TOP_MMC_DLY_CTRL);
	writel_relaxed(ST_TOP_MMC_TX_DLL_STEP_DLY_VALID,
	ioaddr + ST_TOP_MMC_TX_DLL_STEP_DLY);
	}

	static int st_mmcss_lock_dll(void __iomem *ioaddr)
	{
	unsigned long curr, value;
	unsigned long finish = jiffies + HZ;

	/* Checks if the DLL procedure is finished */
	do {
	curr = jiffies;
	value = readl(ioaddr + ST_MMC_STATUS_R);
	if (value & 0x1)
	return 0;

	cpu_relax();
	} while (!time_after_eq(curr, finish));

	return -EBUSY;
	}

	static int sdhci_st_set_dll_for_clock(struct sdhci_host *host)
	{
	int ret = 0;
	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
	struct st_mmc_platform_data *pdata = sdhci_pltfm_priv(pltfm_host);

	if (host->clock > CLK_TO_CHECK_DLL_LOCK) {
	st_mmcss_set_dll(pdata->top_ioaddr);
	ret = st_mmcss_lock_dll(host->ioaddr);
	}

	return ret;
	}

	static void sdhci_st_set_uhs_signaling(struct sdhci_host *host,
	unsigned int uhs)
	{
	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
	struct st_mmc_platform_data *pdata = sdhci_pltfm_priv(pltfm_host);
	u16 ctrl_2 = sdhci_readw(host, SDHCI_HOST_CONTROL2);
	int ret = 0;

	/* Select Bus Speed Mode for host */
	ctrl_2 &= ~SDHCI_CTRL_UHS_MASK;
	switch (uhs) {
	/*
	* Set V18_EN -- UHS modes do not work without this.
	* does not change signaling voltage
	*/

	case MMC_TIMING_UHS_SDR12:
	st_mmcss_set_static_delay(pdata->top_ioaddr);
	ctrl_2 \|= SDHCI_CTRL_UHS_SDR12 \| SDHCI_CTRL_VDD_180;
	break;
	case MMC_TIMING_UHS_SDR25:
	st_mmcss_set_static_delay(pdata->top_ioaddr);
	ctrl_2 \|= SDHCI_CTRL_UHS_SDR25 \| SDHCI_CTRL_VDD_180;
	break;
	case MMC_TIMING_UHS_SDR50:
	st_mmcss_set_static_delay(pdata->top_ioaddr);
	ctrl_2 \|= SDHCI_CTRL_UHS_SDR50 \| SDHCI_CTRL_VDD_180;
	ret = sdhci_st_set_dll_for_clock(host);
	break;
	case MMC_TIMING_UHS_SDR104:
	case MMC_TIMING_MMC_HS200:
	st_mmcss_set_static_delay(pdata->top_ioaddr);
	ctrl_2 \|= SDHCI_CTRL_UHS_SDR104 \| SDHCI_CTRL_VDD_180;
	ret = sdhci_st_set_dll_for_clock(host);
	break;
	case MMC_TIMING_UHS_DDR50:
	case MMC_TIMING_MMC_DDR52:
	st_mmcss_set_static_delay(pdata->top_ioaddr);
	ctrl_2 \|= SDHCI_CTRL_UHS_DDR50 \| SDHCI_CTRL_VDD_180;
	break;
	}

	if (ret)
	dev_warn(mmc_dev(host->mmc), "Error setting dll for clock "
	"(uhs %d)\n", uhs);

	dev_dbg(mmc_dev(host->mmc), "uhs %d, ctrl_2 %04X\n", uhs, ctrl_2);

	sdhci_writew(host, ctrl_2, SDHCI_HOST_CONTROL2);
	}

	static u32 sdhci_st_readl(struct sdhci_host *host, int reg)
	{
	u32 ret;

	switch (reg) {
	case SDHCI_CAPABILITIES:
	ret = readl_relaxed(host->ioaddr + reg);
	/* Support 3.3V and 1.8V */
	ret &= ~SDHCI_CAN_VDD_300;
	break;
	default:
	ret = readl_relaxed(host->ioaddr + reg);
	}
	return ret;
	}

	static const struct sdhci_ops sdhci_st_ops = {
	.get_max_clock = sdhci_pltfm_clk_get_max_clock,
	.set_clock = sdhci_set_clock,
	.set_bus_width = sdhci_set_bus_width,
	.read_l = sdhci_st_readl,
	.reset = sdhci_reset,
	.set_uhs_signaling = sdhci_st_set_uhs_signaling,
	};

	static const struct sdhci_pltfm_data sdhci_st_pdata = {
	.ops = &sdhci_st_ops,
	.quirks = SDHCI_QUIRK_NO_ENDATTR_IN_NOPDESC \|
	SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN \|
	SDHCI_QUIRK_NO_HISPD_BIT,
	.quirks2 = SDHCI_QUIRK2_PRESET_VALUE_BROKEN \|
	SDHCI_QUIRK2_STOP_WITH_TC,
	};


	static int sdhci_st_probe(struct platform_device *pdev)
	{
	struct device_node *np = pdev->dev.of_node;
	struct sdhci_host *host;
	struct st_mmc_platform_data *pdata;
	struct sdhci_pltfm_host *pltfm_host;
	struct clk clk, icnclk;
	int ret = 0;
	u16 host_version;
	struct resource *res;
	struct reset_control *rstc;

	clk = devm_clk_get(&pdev->dev, "mmc");
	if (IS_ERR(clk)) {
	dev_err(&pdev->dev, "Peripheral clk not found\n");
	return PTR_ERR(clk);
	}

	/* ICN clock isn't compulsory, but use it if it's provided. */
	icnclk = devm_clk_get(&pdev->dev, "icn");
	if (IS_ERR(icnclk))
	icnclk = NULL;

	rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
	if (IS_ERR(rstc))
	rstc = NULL;
	else
	reset_control_deassert(rstc);

	host = sdhci_pltfm_init(pdev, &sdhci_st_pdata, sizeof(*pdata));
	if (IS_ERR(host)) {
	dev_err(&pdev->dev, "Failed sdhci_pltfm_init\n");
	ret = PTR_ERR(host);
	goto err_pltfm_init;
	}

	pltfm_host = sdhci_priv(host);
	pdata = sdhci_pltfm_priv(pltfm_host);
	pdata->rstc = rstc;

	ret = mmc_of_parse(host->mmc);
	if (ret) {
	dev_err(&pdev->dev, "Failed mmc_of_parse\n");
	goto err_of;
	}

	ret = clk_prepare_enable(clk);
	if (ret) {
	dev_err(&pdev->dev, "Failed to prepare clock\n");
	goto err_of;
	}

	ret = clk_prepare_enable(icnclk);
	if (ret) {
	dev_err(&pdev->dev, "Failed to prepare icn clock\n");
	goto err_icnclk;
	}

	/* Configure the FlashSS Top registers for setting eMMC TX/RX delay */
	res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
	"top-mmc-delay");
	pdata->top_ioaddr = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(pdata->top_ioaddr)) {
	dev_warn(&pdev->dev, "FlashSS Top Dly registers not available");
	pdata->top_ioaddr = NULL;
	}

	pltfm_host->clk = clk;
	pdata->icnclk = icnclk;

	/* Configure the Arasan HC inside the flashSS */
	st_mmcss_cconfig(np, host);

	ret = sdhci_add_host(host);
	if (ret) {
	dev_err(&pdev->dev, "Failed sdhci_add_host\n");
	goto err_out;
	}

	host_version = readw_relaxed((host->ioaddr + SDHCI_HOST_VERSION));

	dev_info(&pdev->dev, "SDHCI ST Initialised: Host Version: 0x%x Vendor Version 0x%x\n",
	((host_version & SDHCI_SPEC_VER_MASK) >> SDHCI_SPEC_VER_SHIFT),
	((host_version & SDHCI_VENDOR_VER_MASK) >>
	SDHCI_VENDOR_VER_SHIFT));

	return 0;

	err_out:
	clk_disable_unprepare(icnclk);
	err_icnclk:
	clk_disable_unprepare(clk);
	err_of:
	sdhci_pltfm_free(pdev);
	err_pltfm_init:
	if (rstc)
	reset_control_assert(rstc);

	return ret;
	}

	static int sdhci_st_remove(struct platform_device *pdev)
	{
	struct sdhci_host *host = platform_get_drvdata(pdev);
	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
	struct st_mmc_platform_data *pdata = sdhci_pltfm_priv(pltfm_host);
	struct reset_control *rstc = pdata->rstc;
	int ret;

	ret = sdhci_pltfm_unregister(pdev);

	clk_disable_unprepare(pdata->icnclk);

	if (rstc)
	reset_control_assert(rstc);

	return ret;
	}

	#ifdef CONFIG_PM_SLEEP
	static int sdhci_st_suspend(struct device *dev)
	{
	struct sdhci_host *host = dev_get_drvdata(dev);
	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
	struct st_mmc_platform_data *pdata = sdhci_pltfm_priv(pltfm_host);
	int ret;

	if (host->tuning_mode != SDHCI_TUNING_MODE_3)
	mmc_retune_needed(host->mmc);

	ret = sdhci_suspend_host(host);
	if (ret)
	goto out;

	if (pdata->rstc)
	reset_control_assert(pdata->rstc);

	clk_disable_unprepare(pdata->icnclk);
	clk_disable_unprepare(pltfm_host->clk);
	out:
	return ret;
	}

	static int sdhci_st_resume(struct device *dev)
	{
	struct sdhci_host *host = dev_get_drvdata(dev);
	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
	struct st_mmc_platform_data *pdata = sdhci_pltfm_priv(pltfm_host);
	struct device_node *np = dev->of_node;
	int ret;

	ret = clk_prepare_enable(pltfm_host->clk);
	if (ret)
	return ret;

	ret = clk_prepare_enable(pdata->icnclk);
	if (ret) {
	clk_disable_unprepare(pltfm_host->clk);
	return ret;
	}

	if (pdata->rstc)
	reset_control_deassert(pdata->rstc);

	st_mmcss_cconfig(np, host);

	return sdhci_resume_host(host);
	}
	#endif

	static SIMPLE_DEV_PM_OPS(sdhci_st_pmops, sdhci_st_suspend, sdhci_st_resume);

	static const struct of_device_id st_sdhci_match[] = {
	{ .compatible = "st,sdhci" },
	{},
	};

	MODULE_DEVICE_TABLE(of, st_sdhci_match);

	static struct platform_driver sdhci_st_driver = {
	.probe = sdhci_st_probe,
	.remove = sdhci_st_remove,
	.driver = {
	.name = "sdhci-st",
	.pm = &sdhci_st_pmops,
	.of_match_table = of_match_ptr(st_sdhci_match),
	},
	};

	module_platform_driver(sdhci_st_driver);

	MODULE_DESCRIPTION("SDHCI driver for STMicroelectronics SoCs");
	MODULE_AUTHOR("Giuseppe Cavallaro <peppe.cavallaro@st.com>");
	MODULE_LICENSE("GPL v2");
	MODULE_ALIAS("platform:sdhci-st");