drivers/mmc/renesas-sdhi.c - platform/external/u-boot - Gitiles

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * Copyright (C) 2018 Marek Vasut <marek.vasut@gmail.com>
  */

 #include <common.h>
 #include <clk.h>
 #include <fdtdec.h>
 #include <mmc.h>
 #include <dm.h>
 #include <linux/compat.h>
 #include <linux/dma-direction.h>
 #include <linux/io.h>
 #include <linux/sizes.h>
 #include <power/regulator.h>
 #include <asm/unaligned.h>

 #include "tmio-common.h"

 #if CONFIG_IS_ENABLED(MMC_HS200_SUPPORT)

 /* SCC registers */
 #define RENESAS_SDHI_SCC_DTCNTL			0x800
 #define   RENESAS_SDHI_SCC_DTCNTL_TAPEN		BIT(0)
 #define   RENESAS_SDHI_SCC_DTCNTL_TAPNUM_SHIFT	16
 #define   RENESAS_SDHI_SCC_DTCNTL_TAPNUM_MASK		0xff
 #define RENESAS_SDHI_SCC_TAPSET			0x804
 #define RENESAS_SDHI_SCC_DT2FF			0x808
 #define RENESAS_SDHI_SCC_CKSEL			0x80c
 #define   RENESAS_SDHI_SCC_CKSEL_DTSEL		BIT(0)
 #define RENESAS_SDHI_SCC_RVSCNTL			0x810
 #define   RENESAS_SDHI_SCC_RVSCNTL_RVSEN		BIT(0)
 #define RENESAS_SDHI_SCC_RVSREQ			0x814
 #define   RENESAS_SDHI_SCC_RVSREQ_RVSERR		BIT(2)
 #define RENESAS_SDHI_SCC_SMPCMP			0x818
 #define RENESAS_SDHI_SCC_TMPPORT2			0x81c
 #define   RENESAS_SDHI_SCC_TMPPORT2_HS400EN		BIT(31)
 #define   RENESAS_SDHI_SCC_TMPPORT2_HS400OSEL		BIT(4)

 #define RENESAS_SDHI_MAX_TAP 3

 static unsigned int renesas_sdhi_init_tuning(struct tmio_sd_priv *priv)
 {
 	u32 reg;

 	/* Initialize SCC */
 	tmio_sd_writel(priv, 0, TMIO_SD_INFO1);

 	reg = tmio_sd_readl(priv, TMIO_SD_CLKCTL);
 	reg &= ~TMIO_SD_CLKCTL_SCLKEN;
 	tmio_sd_writel(priv, reg, TMIO_SD_CLKCTL);

 	/* Set sampling clock selection range */
 	tmio_sd_writel(priv, 0x8 << RENESAS_SDHI_SCC_DTCNTL_TAPNUM_SHIFT,
 			   RENESAS_SDHI_SCC_DTCNTL);

 	reg = tmio_sd_readl(priv, RENESAS_SDHI_SCC_DTCNTL);
 	reg |= RENESAS_SDHI_SCC_DTCNTL_TAPEN;
 	tmio_sd_writel(priv, reg, RENESAS_SDHI_SCC_DTCNTL);

 	reg = tmio_sd_readl(priv, RENESAS_SDHI_SCC_CKSEL);
 	reg |= RENESAS_SDHI_SCC_CKSEL_DTSEL;
 	tmio_sd_writel(priv, reg, RENESAS_SDHI_SCC_CKSEL);

 	reg = tmio_sd_readl(priv, RENESAS_SDHI_SCC_RVSCNTL);
 	reg &= ~RENESAS_SDHI_SCC_RVSCNTL_RVSEN;
 	tmio_sd_writel(priv, reg, RENESAS_SDHI_SCC_RVSCNTL);

 	tmio_sd_writel(priv, 0x300 /* scc_tappos */,
 			   RENESAS_SDHI_SCC_DT2FF);

 	reg = tmio_sd_readl(priv, TMIO_SD_CLKCTL);
 	reg |= TMIO_SD_CLKCTL_SCLKEN;
 	tmio_sd_writel(priv, reg, TMIO_SD_CLKCTL);

 	/* Read TAPNUM */
 	return (tmio_sd_readl(priv, RENESAS_SDHI_SCC_DTCNTL) >>
 		RENESAS_SDHI_SCC_DTCNTL_TAPNUM_SHIFT) &
 		RENESAS_SDHI_SCC_DTCNTL_TAPNUM_MASK;
 }

 static void renesas_sdhi_reset_tuning(struct tmio_sd_priv *priv)
 {
 	u32 reg;

 	/* Reset SCC */
 	reg = tmio_sd_readl(priv, TMIO_SD_CLKCTL);
 	reg &= ~TMIO_SD_CLKCTL_SCLKEN;
 	tmio_sd_writel(priv, reg, TMIO_SD_CLKCTL);

 	reg = tmio_sd_readl(priv, RENESAS_SDHI_SCC_CKSEL);
 	reg &= ~RENESAS_SDHI_SCC_CKSEL_DTSEL;
 	tmio_sd_writel(priv, reg, RENESAS_SDHI_SCC_CKSEL);

 	reg = tmio_sd_readl(priv, RENESAS_SDHI_SCC_TMPPORT2);
 	reg &= ~(RENESAS_SDHI_SCC_TMPPORT2_HS400EN |
 		 RENESAS_SDHI_SCC_TMPPORT2_HS400OSEL);
 	tmio_sd_writel(priv, reg, RENESAS_SDHI_SCC_TMPPORT2);

 	reg = tmio_sd_readl(priv, TMIO_SD_CLKCTL);
 	reg |= TMIO_SD_CLKCTL_SCLKEN;
 	tmio_sd_writel(priv, reg, TMIO_SD_CLKCTL);

 	reg = tmio_sd_readl(priv, RENESAS_SDHI_SCC_RVSCNTL);
 	reg &= ~RENESAS_SDHI_SCC_RVSCNTL_RVSEN;
 	tmio_sd_writel(priv, reg, RENESAS_SDHI_SCC_RVSCNTL);

 	reg = tmio_sd_readl(priv, RENESAS_SDHI_SCC_RVSCNTL);
 	reg &= ~RENESAS_SDHI_SCC_RVSCNTL_RVSEN;
 	tmio_sd_writel(priv, reg, RENESAS_SDHI_SCC_RVSCNTL);
 }

 static void renesas_sdhi_prepare_tuning(struct tmio_sd_priv *priv,
 				       unsigned long tap)
 {
 	/* Set sampling clock position */
 	tmio_sd_writel(priv, tap, RENESAS_SDHI_SCC_TAPSET);
 }

 static unsigned int renesas_sdhi_compare_scc_data(struct tmio_sd_priv *priv)
 {
 	/* Get comparison of sampling data */
 	return tmio_sd_readl(priv, RENESAS_SDHI_SCC_SMPCMP);
 }

 static int renesas_sdhi_select_tuning(struct tmio_sd_priv *priv,
 				     unsigned int tap_num, unsigned int taps,
 				     unsigned int smpcmp)
 {
 	unsigned long tap_cnt;  /* counter of tuning success */
 	unsigned long tap_set;  /* tap position */
 	unsigned long tap_start;/* start position of tuning success */
 	unsigned long tap_end;  /* end position of tuning success */
 	unsigned long ntap;     /* temporary counter of tuning success */
 	unsigned long match_cnt;/* counter of matching data */
 	unsigned long i;
 	bool select = false;
 	u32 reg;

 	/* Clear SCC_RVSREQ */
 	tmio_sd_writel(priv, 0, RENESAS_SDHI_SCC_RVSREQ);

 	/* Merge the results */
 	for (i = 0; i < tap_num * 2; i++) {
 		if (!(taps & BIT(i))) {
 			taps &= ~BIT(i % tap_num);
 			taps &= ~BIT((i % tap_num) + tap_num);
 		}
 		if (!(smpcmp & BIT(i))) {
 			smpcmp &= ~BIT(i % tap_num);
 			smpcmp &= ~BIT((i % tap_num) + tap_num);
 		}
 	}

 	/*
 	 * Find the longest consecutive run of successful probes.  If that
 	 * is more than RENESAS_SDHI_MAX_TAP probes long then use the
 	 * center index as the tap.
 	 */
 	tap_cnt = 0;
 	ntap = 0;
 	tap_start = 0;
 	tap_end = 0;
 	for (i = 0; i < tap_num * 2; i++) {
 		if (taps & BIT(i))
 			ntap++;
 		else {
 			if (ntap > tap_cnt) {
 				tap_start = i - ntap;
 				tap_end = i - 1;
 				tap_cnt = ntap;
 			}
 			ntap = 0;
 		}
 	}

 	if (ntap > tap_cnt) {
 		tap_start = i - ntap;
 		tap_end = i - 1;
 		tap_cnt = ntap;
 	}

 	/*
 	 * If all of the TAP is OK, the sampling clock position is selected by
 	 * identifying the change point of data.
 	 */
 	if (tap_cnt == tap_num * 2) {
 		match_cnt = 0;
 		ntap = 0;
 		tap_start = 0;
 		tap_end = 0;
 		for (i = 0; i < tap_num * 2; i++) {
 			if (smpcmp & BIT(i))
 				ntap++;
 			else {
 				if (ntap > match_cnt) {
 					tap_start = i - ntap;
 					tap_end = i - 1;
 					match_cnt = ntap;
 				}
 				ntap = 0;
 			}
 		}
 		if (ntap > match_cnt) {
 			tap_start = i - ntap;
 			tap_end = i - 1;
 			match_cnt = ntap;
 		}
 		if (match_cnt)
 			select = true;
 	} else if (tap_cnt >= RENESAS_SDHI_MAX_TAP)
 		select = true;

 	if (select)
 		tap_set = ((tap_start + tap_end) / 2) % tap_num;
 	else
 		return -EIO;

 	/* Set SCC */
 	tmio_sd_writel(priv, tap_set, RENESAS_SDHI_SCC_TAPSET);

 	/* Enable auto re-tuning */
 	reg = tmio_sd_readl(priv, RENESAS_SDHI_SCC_RVSCNTL);
 	reg |= RENESAS_SDHI_SCC_RVSCNTL_RVSEN;
 	tmio_sd_writel(priv, reg, RENESAS_SDHI_SCC_RVSCNTL);

 	return 0;
 }

 int renesas_sdhi_execute_tuning(struct udevice *dev, uint opcode)
 {
 	struct tmio_sd_priv *priv = dev_get_priv(dev);
 	struct mmc_uclass_priv *upriv = dev_get_uclass_priv(dev);
 	struct mmc *mmc = upriv->mmc;
 	unsigned int tap_num;
 	unsigned int taps = 0, smpcmp = 0;
 	int i, ret = 0;
 	u32 caps;

 	/* Only supported on Renesas RCar */
 	if (!(priv->caps & TMIO_SD_CAP_RCAR_UHS))
 		return -EINVAL;

 	/* clock tuning is not needed for upto 52MHz */
 	if (!((mmc->selected_mode == MMC_HS_200) ||
 	      (mmc->selected_mode == UHS_SDR104) ||
 	      (mmc->selected_mode == UHS_SDR50)))
 		return 0;

 	tap_num = renesas_sdhi_init_tuning(priv);
 	if (!tap_num)
 		/* Tuning is not supported */
 		goto out;

 	if (tap_num * 2 >= sizeof(taps) * 8) {
 		dev_err(dev,
 			"Too many taps, skipping tuning. Please consider updating size of taps field of tmio_mmc_host\n");
 		goto out;
 	}

 	/* Issue CMD19 twice for each tap */
 	for (i = 0; i < 2 * tap_num; i++) {
 		renesas_sdhi_prepare_tuning(priv, i % tap_num);

 		/* Force PIO for the tuning */
 		caps = priv->caps;
 		priv->caps &= ~TMIO_SD_CAP_DMA_INTERNAL;

 		ret = mmc_send_tuning(mmc, opcode, NULL);

 		priv->caps = caps;

 		if (ret == 0)
 			taps |= BIT(i);

 		ret = renesas_sdhi_compare_scc_data(priv);
 		if (ret == 0)
 			smpcmp |= BIT(i);

 		mdelay(1);
 	}

 	ret = renesas_sdhi_select_tuning(priv, tap_num, taps, smpcmp);

 out:
 	if (ret < 0) {
 		dev_warn(dev, "Tuning procedure failed\n");
 		renesas_sdhi_reset_tuning(priv);
 	}

 	return ret;
 }
 #endif

 static int renesas_sdhi_set_ios(struct udevice *dev)
 {
 	int ret = tmio_sd_set_ios(dev);

 	mdelay(10);

 #if CONFIG_IS_ENABLED(MMC_HS200_SUPPORT)
 	struct tmio_sd_priv *priv = dev_get_priv(dev);

 	if (priv->caps & TMIO_SD_CAP_RCAR_UHS)
 		renesas_sdhi_reset_tuning(priv);
 #endif

 	return ret;
 }

 static const struct dm_mmc_ops renesas_sdhi_ops = {
 	.send_cmd = tmio_sd_send_cmd,
 	.set_ios = renesas_sdhi_set_ios,
 	.get_cd = tmio_sd_get_cd,
 #if CONFIG_IS_ENABLED(MMC_HS200_SUPPORT)
 	.execute_tuning = renesas_sdhi_execute_tuning,
 #endif
 };

 #define RENESAS_GEN2_QUIRKS	TMIO_SD_CAP_RCAR_GEN2
 #define RENESAS_GEN3_QUIRKS				\
 	TMIO_SD_CAP_64BIT | TMIO_SD_CAP_RCAR_GEN3 | TMIO_SD_CAP_RCAR_UHS

 static const struct udevice_id renesas_sdhi_match[] = {
 	{ .compatible = "renesas,sdhi-r8a7790", .data = RENESAS_GEN2_QUIRKS },
 	{ .compatible = "renesas,sdhi-r8a7791", .data = RENESAS_GEN2_QUIRKS },
 	{ .compatible = "renesas,sdhi-r8a7792", .data = RENESAS_GEN2_QUIRKS },
 	{ .compatible = "renesas,sdhi-r8a7793", .data = RENESAS_GEN2_QUIRKS },
 	{ .compatible = "renesas,sdhi-r8a7794", .data = RENESAS_GEN2_QUIRKS },
 	{ .compatible = "renesas,sdhi-r8a7795", .data = RENESAS_GEN3_QUIRKS },
 	{ .compatible = "renesas,sdhi-r8a7796", .data = RENESAS_GEN3_QUIRKS },
 	{ .compatible = "renesas,sdhi-r8a77965", .data = RENESAS_GEN3_QUIRKS },
 	{ .compatible = "renesas,sdhi-r8a77970", .data = RENESAS_GEN3_QUIRKS },
 	{ .compatible = "renesas,sdhi-r8a77990", .data = RENESAS_GEN3_QUIRKS },
 	{ .compatible = "renesas,sdhi-r8a77995", .data = RENESAS_GEN3_QUIRKS },
 	{ /* sentinel */ }
 };

 static int renesas_sdhi_probe(struct udevice *dev)
 {
 	struct tmio_sd_priv *priv = dev_get_priv(dev);
 	u32 quirks = dev_get_driver_data(dev);
 	struct fdt_resource reg_res;
 	struct clk clk;
 	DECLARE_GLOBAL_DATA_PTR;
 	int ret;

 	if (quirks == RENESAS_GEN2_QUIRKS) {
 		ret = fdt_get_resource(gd->fdt_blob, dev_of_offset(dev),
 				       "reg", 0, &reg_res);
 		if (ret < 0) {
 			dev_err(dev, "\"reg\" resource not found, ret=%i\n",
 				ret);
 			return ret;
 		}

 		if (fdt_resource_size(&reg_res) == 0x100)
 			quirks |= TMIO_SD_CAP_16BIT;
 	}

 	ret = clk_get_by_index(dev, 0, &clk);
 	if (ret < 0) {
 		dev_err(dev, "failed to get host clock\n");
 		return ret;
 	}

 	/* set to max rate */
 	priv->mclk = clk_set_rate(&clk, ULONG_MAX);
 	if (IS_ERR_VALUE(priv->mclk)) {
 		dev_err(dev, "failed to set rate for host clock\n");
 		clk_free(&clk);
 		return priv->mclk;
 	}

 	ret = clk_enable(&clk);
 	clk_free(&clk);
 	if (ret) {
 		dev_err(dev, "failed to enable host clock\n");
 		return ret;
 	}

 	ret = tmio_sd_probe(dev, quirks);
 #if CONFIG_IS_ENABLED(MMC_HS200_SUPPORT)
 	if (!ret && (priv->caps & TMIO_SD_CAP_RCAR_UHS))
 		renesas_sdhi_reset_tuning(priv);
 #endif
 	return ret;
 }

 U_BOOT_DRIVER(renesas_sdhi) = {
 	.name = "renesas-sdhi",
 	.id = UCLASS_MMC,
 	.of_match = renesas_sdhi_match,
 	.bind = tmio_sd_bind,
 	.probe = renesas_sdhi_probe,
 	.priv_auto_alloc_size = sizeof(struct tmio_sd_priv),
 	.platdata_auto_alloc_size = sizeof(struct tmio_sd_plat),
 	.ops = &renesas_sdhi_ops,
 };
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* Copyright (C) 2018 Marek Vasut <marek.vasut@gmail.com>
	*/

	#include <common.h>
	#include <clk.h>
	#include <fdtdec.h>
	#include <mmc.h>
	#include <dm.h>
	#include <linux/compat.h>
	#include <linux/dma-direction.h>
	#include <linux/io.h>
	#include <linux/sizes.h>
	#include <power/regulator.h>
	#include <asm/unaligned.h>

	#include "tmio-common.h"

	#if CONFIG_IS_ENABLED(MMC_HS200_SUPPORT)

	/* SCC registers */
	#define RENESAS_SDHI_SCC_DTCNTL 0x800
	#define RENESAS_SDHI_SCC_DTCNTL_TAPEN BIT(0)
	#define RENESAS_SDHI_SCC_DTCNTL_TAPNUM_SHIFT 16
	#define RENESAS_SDHI_SCC_DTCNTL_TAPNUM_MASK 0xff
	#define RENESAS_SDHI_SCC_TAPSET 0x804
	#define RENESAS_SDHI_SCC_DT2FF 0x808
	#define RENESAS_SDHI_SCC_CKSEL 0x80c
	#define RENESAS_SDHI_SCC_CKSEL_DTSEL BIT(0)
	#define RENESAS_SDHI_SCC_RVSCNTL 0x810
	#define RENESAS_SDHI_SCC_RVSCNTL_RVSEN BIT(0)
	#define RENESAS_SDHI_SCC_RVSREQ 0x814
	#define RENESAS_SDHI_SCC_RVSREQ_RVSERR BIT(2)
	#define RENESAS_SDHI_SCC_SMPCMP 0x818
	#define RENESAS_SDHI_SCC_TMPPORT2 0x81c
	#define RENESAS_SDHI_SCC_TMPPORT2_HS400EN BIT(31)
	#define RENESAS_SDHI_SCC_TMPPORT2_HS400OSEL BIT(4)

	#define RENESAS_SDHI_MAX_TAP 3

	static unsigned int renesas_sdhi_init_tuning(struct tmio_sd_priv *priv)
	{
	u32 reg;

	/* Initialize SCC */
	tmio_sd_writel(priv, 0, TMIO_SD_INFO1);

	reg = tmio_sd_readl(priv, TMIO_SD_CLKCTL);
	reg &= ~TMIO_SD_CLKCTL_SCLKEN;
	tmio_sd_writel(priv, reg, TMIO_SD_CLKCTL);

	/* Set sampling clock selection range */
	tmio_sd_writel(priv, 0x8 << RENESAS_SDHI_SCC_DTCNTL_TAPNUM_SHIFT,
	RENESAS_SDHI_SCC_DTCNTL);

	reg = tmio_sd_readl(priv, RENESAS_SDHI_SCC_DTCNTL);
	reg \|= RENESAS_SDHI_SCC_DTCNTL_TAPEN;
	tmio_sd_writel(priv, reg, RENESAS_SDHI_SCC_DTCNTL);

	reg = tmio_sd_readl(priv, RENESAS_SDHI_SCC_CKSEL);
	reg \|= RENESAS_SDHI_SCC_CKSEL_DTSEL;
	tmio_sd_writel(priv, reg, RENESAS_SDHI_SCC_CKSEL);

	reg = tmio_sd_readl(priv, RENESAS_SDHI_SCC_RVSCNTL);
	reg &= ~RENESAS_SDHI_SCC_RVSCNTL_RVSEN;
	tmio_sd_writel(priv, reg, RENESAS_SDHI_SCC_RVSCNTL);

	tmio_sd_writel(priv, 0x300 /* scc_tappos */,
	RENESAS_SDHI_SCC_DT2FF);

	reg = tmio_sd_readl(priv, TMIO_SD_CLKCTL);
	reg \|= TMIO_SD_CLKCTL_SCLKEN;
	tmio_sd_writel(priv, reg, TMIO_SD_CLKCTL);

	/* Read TAPNUM */
	return (tmio_sd_readl(priv, RENESAS_SDHI_SCC_DTCNTL) >>
	RENESAS_SDHI_SCC_DTCNTL_TAPNUM_SHIFT) &
	RENESAS_SDHI_SCC_DTCNTL_TAPNUM_MASK;
	}

	static void renesas_sdhi_reset_tuning(struct tmio_sd_priv *priv)
	{
	u32 reg;

	/* Reset SCC */
	reg = tmio_sd_readl(priv, TMIO_SD_CLKCTL);
	reg &= ~TMIO_SD_CLKCTL_SCLKEN;
	tmio_sd_writel(priv, reg, TMIO_SD_CLKCTL);

	reg = tmio_sd_readl(priv, RENESAS_SDHI_SCC_CKSEL);
	reg &= ~RENESAS_SDHI_SCC_CKSEL_DTSEL;
	tmio_sd_writel(priv, reg, RENESAS_SDHI_SCC_CKSEL);

	reg = tmio_sd_readl(priv, RENESAS_SDHI_SCC_TMPPORT2);
	reg &= ~(RENESAS_SDHI_SCC_TMPPORT2_HS400EN \|
	RENESAS_SDHI_SCC_TMPPORT2_HS400OSEL);
	tmio_sd_writel(priv, reg, RENESAS_SDHI_SCC_TMPPORT2);

	reg = tmio_sd_readl(priv, TMIO_SD_CLKCTL);
	reg \|= TMIO_SD_CLKCTL_SCLKEN;
	tmio_sd_writel(priv, reg, TMIO_SD_CLKCTL);

	reg = tmio_sd_readl(priv, RENESAS_SDHI_SCC_RVSCNTL);
	reg &= ~RENESAS_SDHI_SCC_RVSCNTL_RVSEN;
	tmio_sd_writel(priv, reg, RENESAS_SDHI_SCC_RVSCNTL);

	reg = tmio_sd_readl(priv, RENESAS_SDHI_SCC_RVSCNTL);
	reg &= ~RENESAS_SDHI_SCC_RVSCNTL_RVSEN;
	tmio_sd_writel(priv, reg, RENESAS_SDHI_SCC_RVSCNTL);
	}

	static void renesas_sdhi_prepare_tuning(struct tmio_sd_priv *priv,
	unsigned long tap)
	{
	/* Set sampling clock position */
	tmio_sd_writel(priv, tap, RENESAS_SDHI_SCC_TAPSET);
	}

	static unsigned int renesas_sdhi_compare_scc_data(struct tmio_sd_priv *priv)
	{
	/* Get comparison of sampling data */
	return tmio_sd_readl(priv, RENESAS_SDHI_SCC_SMPCMP);
	}

	static int renesas_sdhi_select_tuning(struct tmio_sd_priv *priv,
	unsigned int tap_num, unsigned int taps,
	unsigned int smpcmp)
	{
	unsigned long tap_cnt; /* counter of tuning success */
	unsigned long tap_set; /* tap position */
	unsigned long tap_start;/* start position of tuning success */
	unsigned long tap_end; /* end position of tuning success */
	unsigned long ntap; /* temporary counter of tuning success */
	unsigned long match_cnt;/* counter of matching data */
	unsigned long i;
	bool select = false;
	u32 reg;

	/* Clear SCC_RVSREQ */
	tmio_sd_writel(priv, 0, RENESAS_SDHI_SCC_RVSREQ);

	/* Merge the results */
	for (i = 0; i < tap_num * 2; i++) {
	if (!(taps & BIT(i))) {
	taps &= ~BIT(i % tap_num);
	taps &= ~BIT((i % tap_num) + tap_num);
	}
	if (!(smpcmp & BIT(i))) {
	smpcmp &= ~BIT(i % tap_num);
	smpcmp &= ~BIT((i % tap_num) + tap_num);
	}
	}

	/*
	* Find the longest consecutive run of successful probes. If that
	* is more than RENESAS_SDHI_MAX_TAP probes long then use the
	* center index as the tap.
	*/
	tap_cnt = 0;
	ntap = 0;
	tap_start = 0;
	tap_end = 0;
	for (i = 0; i < tap_num * 2; i++) {
	if (taps & BIT(i))
	ntap++;
	else {
	if (ntap > tap_cnt) {
	tap_start = i - ntap;
	tap_end = i - 1;
	tap_cnt = ntap;
	}
	ntap = 0;
	}
	}

	if (ntap > tap_cnt) {
	tap_start = i - ntap;
	tap_end = i - 1;
	tap_cnt = ntap;
	}

	/*
	* If all of the TAP is OK, the sampling clock position is selected by
	* identifying the change point of data.
	*/
	if (tap_cnt == tap_num * 2) {
	match_cnt = 0;
	ntap = 0;
	tap_start = 0;
	tap_end = 0;
	for (i = 0; i < tap_num * 2; i++) {
	if (smpcmp & BIT(i))
	ntap++;
	else {
	if (ntap > match_cnt) {
	tap_start = i - ntap;
	tap_end = i - 1;
	match_cnt = ntap;
	}
	ntap = 0;
	}
	}
	if (ntap > match_cnt) {
	tap_start = i - ntap;
	tap_end = i - 1;
	match_cnt = ntap;
	}
	if (match_cnt)
	select = true;
	} else if (tap_cnt >= RENESAS_SDHI_MAX_TAP)
	select = true;

	if (select)
	tap_set = ((tap_start + tap_end) / 2) % tap_num;
	else
	return -EIO;

	/* Set SCC */
	tmio_sd_writel(priv, tap_set, RENESAS_SDHI_SCC_TAPSET);

	/* Enable auto re-tuning */
	reg = tmio_sd_readl(priv, RENESAS_SDHI_SCC_RVSCNTL);
	reg \|= RENESAS_SDHI_SCC_RVSCNTL_RVSEN;
	tmio_sd_writel(priv, reg, RENESAS_SDHI_SCC_RVSCNTL);

	return 0;
	}

	int renesas_sdhi_execute_tuning(struct udevice *dev, uint opcode)
	{
	struct tmio_sd_priv *priv = dev_get_priv(dev);
	struct mmc_uclass_priv *upriv = dev_get_uclass_priv(dev);
	struct mmc *mmc = upriv->mmc;
	unsigned int tap_num;
	unsigned int taps = 0, smpcmp = 0;
	int i, ret = 0;
	u32 caps;

	/* Only supported on Renesas RCar */
	if (!(priv->caps & TMIO_SD_CAP_RCAR_UHS))
	return -EINVAL;

	/* clock tuning is not needed for upto 52MHz */
	if (!((mmc->selected_mode == MMC_HS_200) \|\|
	(mmc->selected_mode == UHS_SDR104) \|\|
	(mmc->selected_mode == UHS_SDR50)))
	return 0;

	tap_num = renesas_sdhi_init_tuning(priv);
	if (!tap_num)
	/* Tuning is not supported */
	goto out;

	if (tap_num * 2 >= sizeof(taps) * 8) {
	dev_err(dev,
	"Too many taps, skipping tuning. Please consider updating size of taps field of tmio_mmc_host\n");
	goto out;
	}

	/* Issue CMD19 twice for each tap */
	for (i = 0; i < 2 * tap_num; i++) {
	renesas_sdhi_prepare_tuning(priv, i % tap_num);

	/* Force PIO for the tuning */
	caps = priv->caps;
	priv->caps &= ~TMIO_SD_CAP_DMA_INTERNAL;

	ret = mmc_send_tuning(mmc, opcode, NULL);

	priv->caps = caps;

	if (ret == 0)
	taps \|= BIT(i);

	ret = renesas_sdhi_compare_scc_data(priv);
	if (ret == 0)
	smpcmp \|= BIT(i);

	mdelay(1);
	}

	ret = renesas_sdhi_select_tuning(priv, tap_num, taps, smpcmp);

	out:
	if (ret < 0) {
	dev_warn(dev, "Tuning procedure failed\n");
	renesas_sdhi_reset_tuning(priv);
	}

	return ret;
	}
	#endif

	static int renesas_sdhi_set_ios(struct udevice *dev)
	{
	int ret = tmio_sd_set_ios(dev);

	mdelay(10);

	#if CONFIG_IS_ENABLED(MMC_HS200_SUPPORT)
	struct tmio_sd_priv *priv = dev_get_priv(dev);

	if (priv->caps & TMIO_SD_CAP_RCAR_UHS)
	renesas_sdhi_reset_tuning(priv);
	#endif

	return ret;
	}

	static const struct dm_mmc_ops renesas_sdhi_ops = {
	.send_cmd = tmio_sd_send_cmd,
	.set_ios = renesas_sdhi_set_ios,
	.get_cd = tmio_sd_get_cd,
	#if CONFIG_IS_ENABLED(MMC_HS200_SUPPORT)
	.execute_tuning = renesas_sdhi_execute_tuning,
	#endif
	};

	#define RENESAS_GEN2_QUIRKS TMIO_SD_CAP_RCAR_GEN2
	#define RENESAS_GEN3_QUIRKS \
	TMIO_SD_CAP_64BIT \| TMIO_SD_CAP_RCAR_GEN3 \| TMIO_SD_CAP_RCAR_UHS

	static const struct udevice_id renesas_sdhi_match[] = {
	{ .compatible = "renesas,sdhi-r8a7790", .data = RENESAS_GEN2_QUIRKS },
	{ .compatible = "renesas,sdhi-r8a7791", .data = RENESAS_GEN2_QUIRKS },
	{ .compatible = "renesas,sdhi-r8a7792", .data = RENESAS_GEN2_QUIRKS },
	{ .compatible = "renesas,sdhi-r8a7793", .data = RENESAS_GEN2_QUIRKS },
	{ .compatible = "renesas,sdhi-r8a7794", .data = RENESAS_GEN2_QUIRKS },
	{ .compatible = "renesas,sdhi-r8a7795", .data = RENESAS_GEN3_QUIRKS },
	{ .compatible = "renesas,sdhi-r8a7796", .data = RENESAS_GEN3_QUIRKS },
	{ .compatible = "renesas,sdhi-r8a77965", .data = RENESAS_GEN3_QUIRKS },
	{ .compatible = "renesas,sdhi-r8a77970", .data = RENESAS_GEN3_QUIRKS },
	{ .compatible = "renesas,sdhi-r8a77990", .data = RENESAS_GEN3_QUIRKS },
	{ .compatible = "renesas,sdhi-r8a77995", .data = RENESAS_GEN3_QUIRKS },
	{ /* sentinel */ }
	};

	static int renesas_sdhi_probe(struct udevice *dev)
	{
	struct tmio_sd_priv *priv = dev_get_priv(dev);
	u32 quirks = dev_get_driver_data(dev);
	struct fdt_resource reg_res;
	struct clk clk;
	DECLARE_GLOBAL_DATA_PTR;
	int ret;

	if (quirks == RENESAS_GEN2_QUIRKS) {
	ret = fdt_get_resource(gd->fdt_blob, dev_of_offset(dev),
	"reg", 0, &reg_res);
	if (ret < 0) {
	dev_err(dev, "\"reg\" resource not found, ret=%i\n",
	ret);
	return ret;
	}

	if (fdt_resource_size(&reg_res) == 0x100)
	quirks \|= TMIO_SD_CAP_16BIT;
	}

	ret = clk_get_by_index(dev, 0, &clk);
	if (ret < 0) {
	dev_err(dev, "failed to get host clock\n");
	return ret;
	}

	/* set to max rate */
	priv->mclk = clk_set_rate(&clk, ULONG_MAX);
	if (IS_ERR_VALUE(priv->mclk)) {
	dev_err(dev, "failed to set rate for host clock\n");
	clk_free(&clk);
	return priv->mclk;
	}

	ret = clk_enable(&clk);
	clk_free(&clk);
	if (ret) {
	dev_err(dev, "failed to enable host clock\n");
	return ret;
	}

	ret = tmio_sd_probe(dev, quirks);
	#if CONFIG_IS_ENABLED(MMC_HS200_SUPPORT)
	if (!ret && (priv->caps & TMIO_SD_CAP_RCAR_UHS))
	renesas_sdhi_reset_tuning(priv);
	#endif
	return ret;
	}

	U_BOOT_DRIVER(renesas_sdhi) = {
	.name = "renesas-sdhi",
	.id = UCLASS_MMC,
	.of_match = renesas_sdhi_match,
	.bind = tmio_sd_bind,
	.probe = renesas_sdhi_probe,
	.priv_auto_alloc_size = sizeof(struct tmio_sd_priv),
	.platdata_auto_alloc_size = sizeof(struct tmio_sd_plat),
	.ops = &renesas_sdhi_ops,
	};