[v3,2/4] mmc: dw_mmc: exynos: support eMMC's HS400 mode

From: Seungwon Jeon <tgih.jun@samsung.com>

Implements HS400 support for exynos host driver.
And this patch includes some updates as new mode is added.

Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com>
Signed-off-by: Alim Akhtar <alim.akhtar@samsung.com>
---
 .../devicetree/bindings/mmc/exynos-dw-mshc.txt     |    6 +
 drivers/mmc/host/dw_mmc-exynos.c                   |  177 +++++++++++++++-----
 drivers/mmc/host/dw_mmc-exynos.h                   |   17 +-
 drivers/mmc/host/dw_mmc.c                          |   16 +-
 drivers/mmc/host/dw_mmc.h                          |    2 +
 5 files changed, 178 insertions(+), 40 deletions(-)

On 12/31/2014 03:43 PM, Alim Akhtar wrote:
> From: Seungwon Jeon <tgih.jun@samsung.com>
> 
> Implements HS400 support for exynos host driver.
> And this patch includes some updates as new mode is added.
> 
> Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com>
> Signed-off-by: Alim Akhtar <alim.akhtar@samsung.com>
> ---
>  .../devicetree/bindings/mmc/exynos-dw-mshc.txt     |    6 +
>  drivers/mmc/host/dw_mmc-exynos.c                   |  177 +++++++++++++++-----
>  drivers/mmc/host/dw_mmc-exynos.h                   |   17 +-
>  drivers/mmc/host/dw_mmc.c                          |   16 +-
>  drivers/mmc/host/dw_mmc.h                          |    2 +
>  5 files changed, 178 insertions(+), 40 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/mmc/exynos-dw-mshc.txt b/Documentation/devicetree/bindings/mmc/exynos-dw-mshc.txt
> index 06455de..be30c94 100644
> --- a/Documentation/devicetree/bindings/mmc/exynos-dw-mshc.txt
> +++ b/Documentation/devicetree/bindings/mmc/exynos-dw-mshc.txt
> @@ -34,6 +34,7 @@ Required Properties:
>    valid values.
>  
>  * samsung,dw-mshc-hs200-timing: Similar with dw-mshc-sdr-timing.
> +* samsung,dw-mshc-hs400-timing: Similar with dw-mshc-ddr-timing.
>  
>    Notes for the sdr-timing and ddr-timing values:
>  
> @@ -51,6 +52,9 @@ Required Properties:
>        - if CIU clock divider value is 0 (that is divide by 1), both tx and rx
>          phase shift clocks should be 0.
>  
> +* read-strobe-delay: RCLK (Data strobe) delay to control HS400 mode
> +  (Latency value for delay line in Read path)
> +
>  Required properties for a slot (Deprecated - Recommend to use one slot per host):
>  
>  * gpios: specifies a list of gpios used for command, clock and data bus. The
> @@ -83,5 +87,7 @@ Example:
>  		samsung,dw-mshc-sdr-timing = <2 3 3>;
>  		samsung,dw-mshc-ddr-timing = <1 2 3>;
>  		samsung,dw-mshc-hs200-timing = <0 2 3>;
> +		samsung,dw-mshc-hs400-timing = <0 2 1>;
> +		read-strobe-delay = <90>;
>  		bus-width = <8>;
>  	};
> diff --git a/drivers/mmc/host/dw_mmc-exynos.c b/drivers/mmc/host/dw_mmc-exynos.c
> index be6530e..d37a631 100644
> --- a/drivers/mmc/host/dw_mmc-exynos.c
> +++ b/drivers/mmc/host/dw_mmc-exynos.c
> @@ -41,7 +41,12 @@ struct dw_mci_exynos_priv_data {
>  	u32				sdr_timing;
>  	u32				ddr_timing;
>  	u32				hs200_timing;
> +	u32				hs400_timing;
> +	u32				tuned_sample;
>  	u32				cur_speed;
> +	u32				dqs_delay;
> +	u32				saved_dqs_en;
> +	u32				saved_strobe_ctrl;
>  };
>  
>  static struct dw_mci_exynos_compatible {
> @@ -101,6 +106,16 @@ static int dw_mci_exynos_priv_init(struct dw_mci *host)
>  			   SDMMC_MPSCTRL_NON_SECURE_WRITE_BIT);
>  	}
>  
> +	if (priv->ctrl_type >= DW_MCI_TYPE_EXYNOS5420) {
> +		priv->saved_strobe_ctrl = mci_readl(host, HS400_DLINE_CTRL);
> +		priv->saved_dqs_en = mci_readl(host, HS400_DQS_EN);
> +		priv->saved_dqs_en |= AXI_NON_BLOCKING_WR;
> +		mci_writel(host, HS400_DQS_EN, priv->saved_dqs_en);
> +		if (!priv->dqs_delay)
> +			priv->dqs_delay =
> +				DQS_CTRL_GET_RD_DELAY(priv->saved_strobe_ctrl);
> +	}
> +
>  	priv->ciu_div = dw_mci_exynos_get_ciu_div(host);
>  
>  	return 0;
> @@ -115,6 +130,25 @@ static int dw_mci_exynos_setup_clock(struct dw_mci *host)
>  	return 0;
>  }
>  
> +static void dw_mci_exynos_set_clksel_timing(struct dw_mci *host, u32 timing)
> +{
> +	struct dw_mci_exynos_priv_data *priv = host->priv;
> +	u32 clksel;
> +
> +	if (priv->ctrl_type == DW_MCI_TYPE_EXYNOS7 ||
> +		priv->ctrl_type == DW_MCI_TYPE_EXYNOS7_SMU)
> +		clksel = mci_readl(host, CLKSEL64);
> +	else
> +		clksel = mci_readl(host, CLKSEL);
> +
> +	clksel = (clksel & ~SDMMC_CLKSEL_TIMING_MASK) | timing;
> +	if (priv->ctrl_type == DW_MCI_TYPE_EXYNOS7 ||
> +		priv->ctrl_type == DW_MCI_TYPE_EXYNOS7_SMU)
> +		mci_writel(host, CLKSEL64, clksel);
> +	else
> +		mci_writel(host, CLKSEL, clksel);
> +}
> +
>  #ifdef CONFIG_PM_SLEEP
>  static int dw_mci_exynos_suspend(struct device *dev)
>  {
> @@ -190,35 +224,37 @@ static void dw_mci_exynos_prepare_command(struct dw_mci *host, u32 *cmdr)
>  	}
>  }
>  
> -static void dw_mci_exynos_set_ios(struct dw_mci *host, struct mmc_ios *ios)
> +static void dw_mci_exynos_config_hs400(struct dw_mci *host, u32 timing)
>  {
>  	struct dw_mci_exynos_priv_data *priv = host->priv;
> -	unsigned int wanted = ios->clock;
> -	unsigned long actual;
> +	u32 dqs, strobe;
>  
> -	if (ios->timing == MMC_TIMING_MMC_HS200) {
> -		if (priv->ctrl_type == DW_MCI_TYPE_EXYNOS7 ||
> -			priv->ctrl_type == DW_MCI_TYPE_EXYNOS7_SMU)
> -			mci_writel(host, CLKSEL64, priv->hs200_timing);
> -		else
> -			mci_writel(host, CLKSEL, priv->hs200_timing);
> -	} else if (ios->timing == MMC_TIMING_MMC_DDR52) {
> -		if (priv->ctrl_type == DW_MCI_TYPE_EXYNOS7 ||
> -			priv->ctrl_type == DW_MCI_TYPE_EXYNOS7_SMU)
> -			mci_writel(host, CLKSEL64, priv->ddr_timing);
> -		else
> -			mci_writel(host, CLKSEL, priv->ddr_timing);
> -		/* Should be double rate for DDR mode */
> -		if (ios->bus_width == MMC_BUS_WIDTH_8)
> -			wanted <<= 1;
> +	/*
> +	 * Exynos5420 and above controller supports HS400 mode
> +	 */
> +	if (priv->ctrl_type < DW_MCI_TYPE_EXYNOS5420)
> +		return;
> +
> +	dqs = priv->saved_dqs_en;
> +	strobe = priv->saved_strobe_ctrl;
> +
> +	if (timing == MMC_TIMING_MMC_HS400) {
> +		dqs |= DATA_STROBE_EN;
> +		strobe = DQS_CTRL_RD_DELAY(strobe, priv->dqs_delay);
>  	} else {
> -		if (priv->ctrl_type == DW_MCI_TYPE_EXYNOS7 ||
> -			priv->ctrl_type == DW_MCI_TYPE_EXYNOS7_SMU)
> -			mci_writel(host, CLKSEL64, priv->sdr_timing);
> -		else
> -			mci_writel(host, CLKSEL, priv->sdr_timing);
> +		dqs &= ~DATA_STROBE_EN;
>  	}
>  
> +	mci_writel(host, HS400_DQS_EN, dqs);
> +	mci_writel(host, HS400_DLINE_CTRL, strobe);
> +}
> +
> +static void dw_mci_exynos_adjust_clock(struct dw_mci *host, unsigned int wanted)
> +{
> +	struct dw_mci_exynos_priv_data *priv = host->priv;
> +	unsigned long actual;
> +	u8 div;
> +	int ret;
>  	/*
>  	 * Don't care if wanted clock is zero or
>  	 * ciu clock is unavailable
> @@ -230,18 +266,55 @@ static void dw_mci_exynos_set_ios(struct dw_mci *host, struct mmc_ios *ios)
>  	if (wanted < EXYNOS_CCLKIN_MIN)
>  		wanted = EXYNOS_CCLKIN_MIN;
>  
> -	if (wanted != priv->cur_speed) {
> -		u8 div = dw_mci_exynos_get_ciu_div(host);
> -		int ret = clk_set_rate(host->ciu_clk, wanted * div);
> -		if (ret)
> -			dev_warn(host->dev,
> -				"failed to set clk-rate %u error: %d\n",
> -				 wanted * div, ret);
> -		actual = clk_get_rate(host->ciu_clk);
> -		host->bus_hz = actual / div;
> -		priv->cur_speed = wanted;
> -		host->current_speed = 0;
> +	if (wanted == priv->cur_speed)
> +		return;
> +
> +	div = dw_mci_exynos_get_ciu_div(host);
> +	ret = clk_set_rate(host->ciu_clk, wanted * div);
> +	if (ret)
> +		dev_warn(host->dev,
> +			"failed to set clk-rate %u error: %d\n",
> +			wanted * div, ret);
> +	actual = clk_get_rate(host->ciu_clk);
> +	host->bus_hz = actual / div;
> +	priv->cur_speed = wanted;
> +	host->current_speed = 0;
> +}
> +
> +static void dw_mci_exynos_set_ios(struct dw_mci *host, struct mmc_ios *ios)
> +{
> +	struct dw_mci_exynos_priv_data *priv = host->priv;
> +	unsigned int wanted = ios->clock;
> +	u32 timing = ios->timing, clksel;
> +
> +	switch (timing) {
> +	case MMC_TIMING_MMC_HS400:
> +		/* Update tuned sample timing */
> +		clksel = SDMMC_CLKSEL_UP_SAMPLE(
> +				priv->hs400_timing, priv->tuned_sample);
> +		wanted <<= 1;
> +		break;
> +	case MMC_TIMING_MMC_HS200:
> +		clksel = priv->hs200_timing;
> +		break;
> +	case MMC_TIMING_MMC_DDR52:
> +		clksel = priv->ddr_timing;
> +		/* Should be double rate for DDR mode */
> +		if (ios->bus_width == MMC_BUS_WIDTH_8)
> +			wanted <<= 1;
> +		break;
> +	default:
> +		clksel = priv->sdr_timing;
>  	}
> +
> +	/* Set clock timing for the requested speed mode*/
> +	dw_mci_exynos_set_clksel_timing(host, clksel);
> +
> +	/* Configure setting for HS400 */
> +	dw_mci_exynos_config_hs400(host, timing);
> +
> +	/* Configure clock rate */
> +	dw_mci_exynos_adjust_clock(host, wanted);
>  }
>  
>  static int dw_mci_exynos_dt_populate_timing(struct dw_mci *host,
> @@ -294,6 +367,14 @@ static int dw_mci_exynos_parse_dt(struct dw_mci *host)
>  
>  	dw_mci_exynos_dt_populate_timing(host, priv->ctrl_type,
>  		"samsung,dw-mshc-hs200-timing", &priv->hs200_timing);
> +
> +	ret = dw_mci_exynos_dt_populate_timing(host, priv->ctrl_type,
> +			"samsung,dw-mshc-hs400-timing", &priv->hs400_timing);
> +	if (!ret && of_property_read_u32(np,
> +				"read-strobe-delay", &priv->dqs_delay))
> +		dev_info(host->dev,
> +			"read-strobe-delay is not found, assuming usage of default value\n");
> +
>  	host->priv = priv;
>  
>  	return 0;
> @@ -320,7 +401,9 @@ static inline void dw_mci_exynos_set_clksmpl(struct dw_mci *host, u8 sample)
>  		clksel = mci_readl(host, CLKSEL64);
>  	else
>  		clksel = mci_readl(host, CLKSEL);
> -	clksel = (clksel & ~0x7) | SDMMC_CLKSEL_CCLK_SAMPLE(sample);
> +
> +	clksel = SDMMC_CLKSEL_UP_SAMPLE(clksel, sample);
> +
>  	if (priv->ctrl_type == DW_MCI_TYPE_EXYNOS7 ||
>  		priv->ctrl_type == DW_MCI_TYPE_EXYNOS7_SMU)
>  		mci_writel(host, CLKSEL64, clksel);
> @@ -339,13 +422,16 @@ static inline u8 dw_mci_exynos_move_next_clksmpl(struct dw_mci *host)
>  		clksel = mci_readl(host, CLKSEL64);
>  	else
>  		clksel = mci_readl(host, CLKSEL);
> +
>  	sample = (clksel + 1) & 0x7;
> -	clksel = (clksel & ~0x7) | sample;
> +	clksel = SDMMC_CLKSEL_UP_SAMPLE(clksel, sample);
> +
>  	if (priv->ctrl_type == DW_MCI_TYPE_EXYNOS7 ||
>  		priv->ctrl_type == DW_MCI_TYPE_EXYNOS7_SMU)
>  		mci_writel(host, CLKSEL64, clksel);
>  	else
>  		mci_writel(host, CLKSEL, clksel);
> +
>  	return sample;
>  }
>  
> @@ -378,6 +464,7 @@ out:
>  static int dw_mci_exynos_execute_tuning(struct dw_mci_slot *slot)
>  {
>  	struct dw_mci *host = slot->host;
> +	struct dw_mci_exynos_priv_data *priv = host->priv;
>  	struct mmc_host *mmc = slot->mmc;
>  	u8 start_smpl, smpl, candiates = 0;
>  	s8 found = -1;
> @@ -395,14 +482,27 @@ static int dw_mci_exynos_execute_tuning(struct dw_mci_slot *slot)
>  	} while (start_smpl != smpl);
>  
>  	found = dw_mci_exynos_get_best_clksmpl(candiates);
> -	if (found >= 0)
> +	if (found >= 0) {
>  		dw_mci_exynos_set_clksmpl(host, found);
> -	else
> +		priv->tuned_sample = found;
> +	} else {
>  		ret = -EIO;
> +	}
>  
>  	return ret;
>  }
>  
> +int dw_mci_exynos_prepare_hs400_tuning(struct dw_mci *host,
> +					struct mmc_ios *ios)
> +{
> +	struct dw_mci_exynos_priv_data *priv = host->priv;
> +
> +	dw_mci_exynos_set_clksel_timing(host, priv->hs400_timing);
> +	dw_mci_exynos_adjust_clock(host, (ios->clock) << 1);
> +
> +	return 0;
> +}
> +
>  /* Common capabilities of Exynos4/Exynos5 SoC */
>  static unsigned long exynos_dwmmc_caps[4] = {
>  	MMC_CAP_1_8V_DDR | MMC_CAP_8_BIT_DATA | MMC_CAP_CMD23,
> @@ -419,6 +519,7 @@ static const struct dw_mci_drv_data exynos_drv_data = {
>  	.set_ios		= dw_mci_exynos_set_ios,
>  	.parse_dt		= dw_mci_exynos_parse_dt,
>  	.execute_tuning		= dw_mci_exynos_execute_tuning,
> +	.prepare_hs400_tuning	= dw_mci_exynos_prepare_hs400_tuning,
>  };
>  
>  static const struct of_device_id dw_mci_exynos_match[] = {
> diff --git a/drivers/mmc/host/dw_mmc-exynos.h b/drivers/mmc/host/dw_mmc-exynos.h
> index c04ecef..e7faffe 100644
> --- a/drivers/mmc/host/dw_mmc-exynos.h
> +++ b/drivers/mmc/host/dw_mmc-exynos.h
> @@ -12,21 +12,36 @@
>  #ifndef _DW_MMC_EXYNOS_H_
>  #define _DW_MMC_EXYNOS_H_
>  
> -/* Extended Register's Offset */
>  #define SDMMC_CLKSEL			0x09C
>  #define SDMMC_CLKSEL64			0x0A8
>  
> +/* Extended Register's Offset */
> +#define SDMMC_HS400_DQS_EN		0x180
> +#define SDMMC_HS400_ASYNC_FIFO_CTRL	0x184
> +#define SDMMC_HS400_DLINE_CTRL		0x188
> +
>  /* CLKSEL register defines */
>  #define SDMMC_CLKSEL_CCLK_SAMPLE(x)	(((x) & 7) << 0)
>  #define SDMMC_CLKSEL_CCLK_DRIVE(x)	(((x) & 7) << 16)
>  #define SDMMC_CLKSEL_CCLK_DIVIDER(x)	(((x) & 7) << 24)
>  #define SDMMC_CLKSEL_GET_DRV_WD3(x)	(((x) >> 16) & 0x7)
>  #define SDMMC_CLKSEL_GET_DIV(x)		(((x) >> 24) & 0x7)
> +#define SDMMC_CLKSEL_UP_SAMPLE(x, y)	(((x) & ~SDMMC_CLKSEL_CCLK_SAMPLE(7)) |\
> +					 SDMMC_CLKSEL_CCLK_SAMPLE(y))
>  #define SDMMC_CLKSEL_TIMING(x, y, z)	(SDMMC_CLKSEL_CCLK_SAMPLE(x) |	\
>  					 SDMMC_CLKSEL_CCLK_DRIVE(y) |	\
>  					 SDMMC_CLKSEL_CCLK_DIVIDER(z))
> +#define SDMMC_CLKSEL_TIMING_MASK	SDMMC_CLKSEL_TIMING(0x7, 0x7, 0x7)
>  #define SDMMC_CLKSEL_WAKEUP_INT		BIT(11)
>  
> +/* HS400 control defines */
> +#define DATA_STROBE_EN			BIT(0)
Add comment "xxx register defines."

> +#define AXI_NON_BLOCKING_WR	BIT(7)

I can't find this bit and comment..where?

> +
> +/* Delay Line Control defines */
> +#define DQS_CTRL_RD_DELAY(x, y)		(((x) & ~0x3FF) | ((y) & 0x3FF))

I'm not understanding this define... clear and set?

Best Regards,
Jaehoon Chung

> +#define DQS_CTRL_GET_RD_DELAY(x)	((x) & 0x3FF)
> +
>  /* Protector Register */
>  #define SDMMC_EMMCP_BASE	0x1000
>  #define SDMMC_MPSECURITY	(SDMMC_EMMCP_BASE + 0x0010)
> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> index 2e8abc8..43a3a5b 100644
> --- a/drivers/mmc/host/dw_mmc.c
> +++ b/drivers/mmc/host/dw_mmc.c
> @@ -1084,7 +1084,8 @@ static void dw_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
>  	regs = mci_readl(slot->host, UHS_REG);
>  
>  	/* DDR mode set */
> -	if (ios->timing == MMC_TIMING_MMC_DDR52)
> +	if (ios->timing == MMC_TIMING_MMC_DDR52 ||
> +	    ios->timing == MMC_TIMING_MMC_HS400)
>  		regs |= ((0x1 << slot->id) << 16);
>  	else
>  		regs &= ~((0x1 << slot->id) << 16);
> @@ -1321,6 +1322,18 @@ static int dw_mci_execute_tuning(struct mmc_host *mmc, u32 opcode)
>  	return err;
>  }
>  
> +int dw_mci_prepare_hs400_tuning(struct mmc_host *mmc, struct mmc_ios *ios)
> +{
> +	struct dw_mci_slot *slot = mmc_priv(mmc);
> +	struct dw_mci *host = slot->host;
> +	const struct dw_mci_drv_data *drv_data = host->drv_data;
> +
> +	if (drv_data && drv_data->prepare_hs400_tuning)
> +		return drv_data->prepare_hs400_tuning(host, ios);
> +
> +	return 0;
> +}
> +
>  static const struct mmc_host_ops dw_mci_ops = {
>  	.request		= dw_mci_request,
>  	.pre_req		= dw_mci_pre_req,
> @@ -1333,6 +1346,7 @@ static const struct mmc_host_ops dw_mci_ops = {
>  	.card_busy		= dw_mci_card_busy,
>  	.start_signal_voltage_switch = dw_mci_switch_voltage,
>  	.init_card		= dw_mci_init_card,
> +	.prepare_hs400_tuning	= dw_mci_prepare_hs400_tuning,
>  };
>  
>  static void dw_mci_request_end(struct dw_mci *host, struct mmc_request *mrq)
> diff --git a/drivers/mmc/host/dw_mmc.h b/drivers/mmc/host/dw_mmc.h
> index 18c4afe..d239867 100644
> --- a/drivers/mmc/host/dw_mmc.h
> +++ b/drivers/mmc/host/dw_mmc.h
> @@ -271,5 +271,7 @@ struct dw_mci_drv_data {
>  	void		(*set_ios)(struct dw_mci *host, struct mmc_ios *ios);
>  	int		(*parse_dt)(struct dw_mci *host);
>  	int		(*execute_tuning)(struct dw_mci_slot *slot);
> +	int		(*prepare_hs400_tuning)(struct dw_mci *host,
> +						struct mmc_ios *ios);
>  };
>  #endif /* _DW_MMC_H_ */
> 

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Hi Jaehoon,

On Thu, Jan 8, 2015 at 7:16 AM, Jaehoon Chung <jh80.chung@samsung.com> wrote:
> On 12/31/2014 03:43 PM, Alim Akhtar wrote:
>> From: Seungwon Jeon <tgih.jun@samsung.com>
>>
>> Implements HS400 support for exynos host driver.
>> And this patch includes some updates as new mode is added.
>>
>> Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com>
>> Signed-off-by: Alim Akhtar <alim.akhtar@samsung.com>
>> ---
>>  .../devicetree/bindings/mmc/exynos-dw-mshc.txt     |    6 +
>>  drivers/mmc/host/dw_mmc-exynos.c                   |  177 +++++++++++++++-----
>>  drivers/mmc/host/dw_mmc-exynos.h                   |   17 +-
>>  drivers/mmc/host/dw_mmc.c                          |   16 +-
>>  drivers/mmc/host/dw_mmc.h                          |    2 +
>>  5 files changed, 178 insertions(+), 40 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/mmc/exynos-dw-mshc.txt b/Documentation/devicetree/bindings/mmc/exynos-dw-mshc.txt
>> index 06455de..be30c94 100644
>> --- a/Documentation/devicetree/bindings/mmc/exynos-dw-mshc.txt
>> +++ b/Documentation/devicetree/bindings/mmc/exynos-dw-mshc.txt
>> @@ -34,6 +34,7 @@ Required Properties:
>>    valid values.
>>
>>  * samsung,dw-mshc-hs200-timing: Similar with dw-mshc-sdr-timing.
>> +* samsung,dw-mshc-hs400-timing: Similar with dw-mshc-ddr-timing.
>>
>>    Notes for the sdr-timing and ddr-timing values:
>>
>> @@ -51,6 +52,9 @@ Required Properties:
>>        - if CIU clock divider value is 0 (that is divide by 1), both tx and rx
>>          phase shift clocks should be 0.
>>
>> +* read-strobe-delay: RCLK (Data strobe) delay to control HS400 mode
>> +  (Latency value for delay line in Read path)
>> +
>>  Required properties for a slot (Deprecated - Recommend to use one slot per host):
>>
>>  * gpios: specifies a list of gpios used for command, clock and data bus. The
>> @@ -83,5 +87,7 @@ Example:
>>               samsung,dw-mshc-sdr-timing = <2 3 3>;
>>               samsung,dw-mshc-ddr-timing = <1 2 3>;
>>               samsung,dw-mshc-hs200-timing = <0 2 3>;
>> +             samsung,dw-mshc-hs400-timing = <0 2 1>;
>> +             read-strobe-delay = <90>;
>>               bus-width = <8>;
>>       };
>> diff --git a/drivers/mmc/host/dw_mmc-exynos.c b/drivers/mmc/host/dw_mmc-exynos.c
>> index be6530e..d37a631 100644
>> --- a/drivers/mmc/host/dw_mmc-exynos.c
>> +++ b/drivers/mmc/host/dw_mmc-exynos.c
>> @@ -41,7 +41,12 @@ struct dw_mci_exynos_priv_data {
>>       u32                             sdr_timing;
>>       u32                             ddr_timing;
>>       u32                             hs200_timing;
>> +     u32                             hs400_timing;
>> +     u32                             tuned_sample;
>>       u32                             cur_speed;
>> +     u32                             dqs_delay;
>> +     u32                             saved_dqs_en;
>> +     u32                             saved_strobe_ctrl;
>>  };
>>
>>  static struct dw_mci_exynos_compatible {
>> @@ -101,6 +106,16 @@ static int dw_mci_exynos_priv_init(struct dw_mci *host)
>>                          SDMMC_MPSCTRL_NON_SECURE_WRITE_BIT);
>>       }
>>
>> +     if (priv->ctrl_type >= DW_MCI_TYPE_EXYNOS5420) {
>> +             priv->saved_strobe_ctrl = mci_readl(host, HS400_DLINE_CTRL);
>> +             priv->saved_dqs_en = mci_readl(host, HS400_DQS_EN);
>> +             priv->saved_dqs_en |= AXI_NON_BLOCKING_WR;
>> +             mci_writel(host, HS400_DQS_EN, priv->saved_dqs_en);
>> +             if (!priv->dqs_delay)
>> +                     priv->dqs_delay =
>> +                             DQS_CTRL_GET_RD_DELAY(priv->saved_strobe_ctrl);
>> +     }
>> +
>>       priv->ciu_div = dw_mci_exynos_get_ciu_div(host);
>>
>>       return 0;
>> @@ -115,6 +130,25 @@ static int dw_mci_exynos_setup_clock(struct dw_mci *host)
>>       return 0;
>>  }
>>
>> +static void dw_mci_exynos_set_clksel_timing(struct dw_mci *host, u32 timing)
>> +{
>> +     struct dw_mci_exynos_priv_data *priv = host->priv;
>> +     u32 clksel;
>> +
>> +     if (priv->ctrl_type == DW_MCI_TYPE_EXYNOS7 ||
>> +             priv->ctrl_type == DW_MCI_TYPE_EXYNOS7_SMU)
>> +             clksel = mci_readl(host, CLKSEL64);
>> +     else
>> +             clksel = mci_readl(host, CLKSEL);
>> +
>> +     clksel = (clksel & ~SDMMC_CLKSEL_TIMING_MASK) | timing;
>> +     if (priv->ctrl_type == DW_MCI_TYPE_EXYNOS7 ||
>> +             priv->ctrl_type == DW_MCI_TYPE_EXYNOS7_SMU)
>> +             mci_writel(host, CLKSEL64, clksel);
>> +     else
>> +             mci_writel(host, CLKSEL, clksel);
>> +}
>> +
>>  #ifdef CONFIG_PM_SLEEP
>>  static int dw_mci_exynos_suspend(struct device *dev)
>>  {
>> @@ -190,35 +224,37 @@ static void dw_mci_exynos_prepare_command(struct dw_mci *host, u32 *cmdr)
>>       }
>>  }
>>
>> -static void dw_mci_exynos_set_ios(struct dw_mci *host, struct mmc_ios *ios)
>> +static void dw_mci_exynos_config_hs400(struct dw_mci *host, u32 timing)
>>  {
>>       struct dw_mci_exynos_priv_data *priv = host->priv;
>> -     unsigned int wanted = ios->clock;
>> -     unsigned long actual;
>> +     u32 dqs, strobe;
>>
>> -     if (ios->timing == MMC_TIMING_MMC_HS200) {
>> -             if (priv->ctrl_type == DW_MCI_TYPE_EXYNOS7 ||
>> -                     priv->ctrl_type == DW_MCI_TYPE_EXYNOS7_SMU)
>> -                     mci_writel(host, CLKSEL64, priv->hs200_timing);
>> -             else
>> -                     mci_writel(host, CLKSEL, priv->hs200_timing);
>> -     } else if (ios->timing == MMC_TIMING_MMC_DDR52) {
>> -             if (priv->ctrl_type == DW_MCI_TYPE_EXYNOS7 ||
>> -                     priv->ctrl_type == DW_MCI_TYPE_EXYNOS7_SMU)
>> -                     mci_writel(host, CLKSEL64, priv->ddr_timing);
>> -             else
>> -                     mci_writel(host, CLKSEL, priv->ddr_timing);
>> -             /* Should be double rate for DDR mode */
>> -             if (ios->bus_width == MMC_BUS_WIDTH_8)
>> -                     wanted <<= 1;
>> +     /*
>> +      * Exynos5420 and above controller supports HS400 mode
>> +      */
>> +     if (priv->ctrl_type < DW_MCI_TYPE_EXYNOS5420)
>> +             return;
>> +
>> +     dqs = priv->saved_dqs_en;
>> +     strobe = priv->saved_strobe_ctrl;
>> +
>> +     if (timing == MMC_TIMING_MMC_HS400) {
>> +             dqs |= DATA_STROBE_EN;
>> +             strobe = DQS_CTRL_RD_DELAY(strobe, priv->dqs_delay);
>>       } else {
>> -             if (priv->ctrl_type == DW_MCI_TYPE_EXYNOS7 ||
>> -                     priv->ctrl_type == DW_MCI_TYPE_EXYNOS7_SMU)
>> -                     mci_writel(host, CLKSEL64, priv->sdr_timing);
>> -             else
>> -                     mci_writel(host, CLKSEL, priv->sdr_timing);
>> +             dqs &= ~DATA_STROBE_EN;
>>       }
>>
>> +     mci_writel(host, HS400_DQS_EN, dqs);
>> +     mci_writel(host, HS400_DLINE_CTRL, strobe);
>> +}
>> +
>> +static void dw_mci_exynos_adjust_clock(struct dw_mci *host, unsigned int wanted)
>> +{
>> +     struct dw_mci_exynos_priv_data *priv = host->priv;
>> +     unsigned long actual;
>> +     u8 div;
>> +     int ret;
>>       /*
>>        * Don't care if wanted clock is zero or
>>        * ciu clock is unavailable
>> @@ -230,18 +266,55 @@ static void dw_mci_exynos_set_ios(struct dw_mci *host, struct mmc_ios *ios)
>>       if (wanted < EXYNOS_CCLKIN_MIN)
>>               wanted = EXYNOS_CCLKIN_MIN;
>>
>> -     if (wanted != priv->cur_speed) {
>> -             u8 div = dw_mci_exynos_get_ciu_div(host);
>> -             int ret = clk_set_rate(host->ciu_clk, wanted * div);
>> -             if (ret)
>> -                     dev_warn(host->dev,
>> -                             "failed to set clk-rate %u error: %d\n",
>> -                              wanted * div, ret);
>> -             actual = clk_get_rate(host->ciu_clk);
>> -             host->bus_hz = actual / div;
>> -             priv->cur_speed = wanted;
>> -             host->current_speed = 0;
>> +     if (wanted == priv->cur_speed)
>> +             return;
>> +
>> +     div = dw_mci_exynos_get_ciu_div(host);
>> +     ret = clk_set_rate(host->ciu_clk, wanted * div);
>> +     if (ret)
>> +             dev_warn(host->dev,
>> +                     "failed to set clk-rate %u error: %d\n",
>> +                     wanted * div, ret);
>> +     actual = clk_get_rate(host->ciu_clk);
>> +     host->bus_hz = actual / div;
>> +     priv->cur_speed = wanted;
>> +     host->current_speed = 0;
>> +}
>> +
>> +static void dw_mci_exynos_set_ios(struct dw_mci *host, struct mmc_ios *ios)
>> +{
>> +     struct dw_mci_exynos_priv_data *priv = host->priv;
>> +     unsigned int wanted = ios->clock;
>> +     u32 timing = ios->timing, clksel;
>> +
>> +     switch (timing) {
>> +     case MMC_TIMING_MMC_HS400:
>> +             /* Update tuned sample timing */
>> +             clksel = SDMMC_CLKSEL_UP_SAMPLE(
>> +                             priv->hs400_timing, priv->tuned_sample);
>> +             wanted <<= 1;
>> +             break;
>> +     case MMC_TIMING_MMC_HS200:
>> +             clksel = priv->hs200_timing;
>> +             break;
>> +     case MMC_TIMING_MMC_DDR52:
>> +             clksel = priv->ddr_timing;
>> +             /* Should be double rate for DDR mode */
>> +             if (ios->bus_width == MMC_BUS_WIDTH_8)
>> +                     wanted <<= 1;
>> +             break;
>> +     default:
>> +             clksel = priv->sdr_timing;
>>       }
>> +
>> +     /* Set clock timing for the requested speed mode*/
>> +     dw_mci_exynos_set_clksel_timing(host, clksel);
>> +
>> +     /* Configure setting for HS400 */
>> +     dw_mci_exynos_config_hs400(host, timing);
>> +
>> +     /* Configure clock rate */
>> +     dw_mci_exynos_adjust_clock(host, wanted);
>>  }
>>
>>  static int dw_mci_exynos_dt_populate_timing(struct dw_mci *host,
>> @@ -294,6 +367,14 @@ static int dw_mci_exynos_parse_dt(struct dw_mci *host)
>>
>>       dw_mci_exynos_dt_populate_timing(host, priv->ctrl_type,
>>               "samsung,dw-mshc-hs200-timing", &priv->hs200_timing);
>> +
>> +     ret = dw_mci_exynos_dt_populate_timing(host, priv->ctrl_type,
>> +                     "samsung,dw-mshc-hs400-timing", &priv->hs400_timing);
>> +     if (!ret && of_property_read_u32(np,
>> +                             "read-strobe-delay", &priv->dqs_delay))
>> +             dev_info(host->dev,
>> +                     "read-strobe-delay is not found, assuming usage of default value\n");
>> +
>>       host->priv = priv;
>>
>>       return 0;
>> @@ -320,7 +401,9 @@ static inline void dw_mci_exynos_set_clksmpl(struct dw_mci *host, u8 sample)
>>               clksel = mci_readl(host, CLKSEL64);
>>       else
>>               clksel = mci_readl(host, CLKSEL);
>> -     clksel = (clksel & ~0x7) | SDMMC_CLKSEL_CCLK_SAMPLE(sample);
>> +
>> +     clksel = SDMMC_CLKSEL_UP_SAMPLE(clksel, sample);
>> +
>>       if (priv->ctrl_type == DW_MCI_TYPE_EXYNOS7 ||
>>               priv->ctrl_type == DW_MCI_TYPE_EXYNOS7_SMU)
>>               mci_writel(host, CLKSEL64, clksel);
>> @@ -339,13 +422,16 @@ static inline u8 dw_mci_exynos_move_next_clksmpl(struct dw_mci *host)
>>               clksel = mci_readl(host, CLKSEL64);
>>       else
>>               clksel = mci_readl(host, CLKSEL);
>> +
>>       sample = (clksel + 1) & 0x7;
>> -     clksel = (clksel & ~0x7) | sample;
>> +     clksel = SDMMC_CLKSEL_UP_SAMPLE(clksel, sample);
>> +
>>       if (priv->ctrl_type == DW_MCI_TYPE_EXYNOS7 ||
>>               priv->ctrl_type == DW_MCI_TYPE_EXYNOS7_SMU)
>>               mci_writel(host, CLKSEL64, clksel);
>>       else
>>               mci_writel(host, CLKSEL, clksel);
>> +
>>       return sample;
>>  }
>>
>> @@ -378,6 +464,7 @@ out:
>>  static int dw_mci_exynos_execute_tuning(struct dw_mci_slot *slot)
>>  {
>>       struct dw_mci *host = slot->host;
>> +     struct dw_mci_exynos_priv_data *priv = host->priv;
>>       struct mmc_host *mmc = slot->mmc;
>>       u8 start_smpl, smpl, candiates = 0;
>>       s8 found = -1;
>> @@ -395,14 +482,27 @@ static int dw_mci_exynos_execute_tuning(struct dw_mci_slot *slot)
>>       } while (start_smpl != smpl);
>>
>>       found = dw_mci_exynos_get_best_clksmpl(candiates);
>> -     if (found >= 0)
>> +     if (found >= 0) {
>>               dw_mci_exynos_set_clksmpl(host, found);
>> -     else
>> +             priv->tuned_sample = found;
>> +     } else {
>>               ret = -EIO;
>> +     }
>>
>>       return ret;
>>  }
>>
>> +int dw_mci_exynos_prepare_hs400_tuning(struct dw_mci *host,
>> +                                     struct mmc_ios *ios)
>> +{
>> +     struct dw_mci_exynos_priv_data *priv = host->priv;
>> +
>> +     dw_mci_exynos_set_clksel_timing(host, priv->hs400_timing);
>> +     dw_mci_exynos_adjust_clock(host, (ios->clock) << 1);
>> +
>> +     return 0;
>> +}
>> +
>>  /* Common capabilities of Exynos4/Exynos5 SoC */
>>  static unsigned long exynos_dwmmc_caps[4] = {
>>       MMC_CAP_1_8V_DDR | MMC_CAP_8_BIT_DATA | MMC_CAP_CMD23,
>> @@ -419,6 +519,7 @@ static const struct dw_mci_drv_data exynos_drv_data = {
>>       .set_ios                = dw_mci_exynos_set_ios,
>>       .parse_dt               = dw_mci_exynos_parse_dt,
>>       .execute_tuning         = dw_mci_exynos_execute_tuning,
>> +     .prepare_hs400_tuning   = dw_mci_exynos_prepare_hs400_tuning,
>>  };
>>
>>  static const struct of_device_id dw_mci_exynos_match[] = {
>> diff --git a/drivers/mmc/host/dw_mmc-exynos.h b/drivers/mmc/host/dw_mmc-exynos.h
>> index c04ecef..e7faffe 100644
>> --- a/drivers/mmc/host/dw_mmc-exynos.h
>> +++ b/drivers/mmc/host/dw_mmc-exynos.h
>> @@ -12,21 +12,36 @@
>>  #ifndef _DW_MMC_EXYNOS_H_
>>  #define _DW_MMC_EXYNOS_H_
>>
>> -/* Extended Register's Offset */
>>  #define SDMMC_CLKSEL                 0x09C
>>  #define SDMMC_CLKSEL64                       0x0A8
>>
>> +/* Extended Register's Offset */
>> +#define SDMMC_HS400_DQS_EN           0x180
>> +#define SDMMC_HS400_ASYNC_FIFO_CTRL  0x184
>> +#define SDMMC_HS400_DLINE_CTRL               0x188
>> +
>>  /* CLKSEL register defines */
>>  #define SDMMC_CLKSEL_CCLK_SAMPLE(x)  (((x) & 7) << 0)
>>  #define SDMMC_CLKSEL_CCLK_DRIVE(x)   (((x) & 7) << 16)
>>  #define SDMMC_CLKSEL_CCLK_DIVIDER(x) (((x) & 7) << 24)
>>  #define SDMMC_CLKSEL_GET_DRV_WD3(x)  (((x) >> 16) & 0x7)
>>  #define SDMMC_CLKSEL_GET_DIV(x)              (((x) >> 24) & 0x7)
>> +#define SDMMC_CLKSEL_UP_SAMPLE(x, y) (((x) & ~SDMMC_CLKSEL_CCLK_SAMPLE(7)) |\
>> +                                      SDMMC_CLKSEL_CCLK_SAMPLE(y))
>>  #define SDMMC_CLKSEL_TIMING(x, y, z) (SDMMC_CLKSEL_CCLK_SAMPLE(x) |  \
>>                                        SDMMC_CLKSEL_CCLK_DRIVE(y) |   \
>>                                        SDMMC_CLKSEL_CCLK_DIVIDER(z))
>> +#define SDMMC_CLKSEL_TIMING_MASK     SDMMC_CLKSEL_TIMING(0x7, 0x7, 0x7)
>>  #define SDMMC_CLKSEL_WAKEUP_INT              BIT(11)
>>
>> +/* HS400 control defines */
>> +#define DATA_STROBE_EN                       BIT(0)
> Add comment "xxx register defines."
>
Ok, will add
>> +#define AXI_NON_BLOCKING_WR  BIT(7)
>
> I can't find this bit and comment..where?
>
This is Bit[7] of RCLK_EN register.
>> +
>> +/* Delay Line Control defines */
>> +#define DQS_CTRL_RD_DELAY(x, y)              (((x) & ~0x3FF) | ((y) & 0x3FF))
>
> I'm not understanding this define... clear and set?
>
yes, clear default and set the one pass from Device Tree.
> Best Regards,
> Jaehoon Chung
>
>> +#define DQS_CTRL_GET_RD_DELAY(x)     ((x) & 0x3FF)
>> +
>>  /* Protector Register */
>>  #define SDMMC_EMMCP_BASE     0x1000
>>  #define SDMMC_MPSECURITY     (SDMMC_EMMCP_BASE + 0x0010)
>> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
>> index 2e8abc8..43a3a5b 100644
>> --- a/drivers/mmc/host/dw_mmc.c
>> +++ b/drivers/mmc/host/dw_mmc.c
>> @@ -1084,7 +1084,8 @@ static void dw_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
>>       regs = mci_readl(slot->host, UHS_REG);
>>
>>       /* DDR mode set */
>> -     if (ios->timing == MMC_TIMING_MMC_DDR52)
>> +     if (ios->timing == MMC_TIMING_MMC_DDR52 ||
>> +         ios->timing == MMC_TIMING_MMC_HS400)
>>               regs |= ((0x1 << slot->id) << 16);
>>       else
>>               regs &= ~((0x1 << slot->id) << 16);
>> @@ -1321,6 +1322,18 @@ static int dw_mci_execute_tuning(struct mmc_host *mmc, u32 opcode)
>>       return err;
>>  }
>>
>> +int dw_mci_prepare_hs400_tuning(struct mmc_host *mmc, struct mmc_ios *ios)
>> +{
>> +     struct dw_mci_slot *slot = mmc_priv(mmc);
>> +     struct dw_mci *host = slot->host;
>> +     const struct dw_mci_drv_data *drv_data = host->drv_data;
>> +
>> +     if (drv_data && drv_data->prepare_hs400_tuning)
>> +             return drv_data->prepare_hs400_tuning(host, ios);
>> +
>> +     return 0;
>> +}
>> +
>>  static const struct mmc_host_ops dw_mci_ops = {
>>       .request                = dw_mci_request,
>>       .pre_req                = dw_mci_pre_req,
>> @@ -1333,6 +1346,7 @@ static const struct mmc_host_ops dw_mci_ops = {
>>       .card_busy              = dw_mci_card_busy,
>>       .start_signal_voltage_switch = dw_mci_switch_voltage,
>>       .init_card              = dw_mci_init_card,
>> +     .prepare_hs400_tuning   = dw_mci_prepare_hs400_tuning,
>>  };
>>
>>  static void dw_mci_request_end(struct dw_mci *host, struct mmc_request *mrq)
>> diff --git a/drivers/mmc/host/dw_mmc.h b/drivers/mmc/host/dw_mmc.h
>> index 18c4afe..d239867 100644
>> --- a/drivers/mmc/host/dw_mmc.h
>> +++ b/drivers/mmc/host/dw_mmc.h
>> @@ -271,5 +271,7 @@ struct dw_mci_drv_data {
>>       void            (*set_ios)(struct dw_mci *host, struct mmc_ios *ios);
>>       int             (*parse_dt)(struct dw_mci *host);
>>       int             (*execute_tuning)(struct dw_mci_slot *slot);
>> +     int             (*prepare_hs400_tuning)(struct dw_mci *host,
>> +                                             struct mmc_ios *ios);
>>  };
>>  #endif /* _DW_MMC_H_ */
>>
>