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

[Jaehoon Chung <jh80.chung@samsung.com>]

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_ */
>