[U-Boot] [PATCH 1/5] mmc: sunxi: add support for automatic delay calibration

[André Przywara]

On 9/30/18 12:45 AM, Vagrant Cascadian wrote:
> From: Vasily Khoruzhick <anarsoul at gmail.com>
> 
> A64 supports automatic delay calibration and Linux driver uses it
> instead of hardcoded delays. Add support for it to u-boot driver.

So technically that should be derived from the node's compatible string,
like we do in Linux. But I see that we are not there yet in U-Boot.
Meanwhile I don't think you should introduce a new Kconfig option, you
could keep the hacky U-Boot style and just add an
#if defined(CONFIG_MACH_SUN50I) || defined(CONFIG_MACH_SUN50I_H6)
to the two places instead.
A better way would be to introduce a "can_calibrate" member to struct
sunxi_mmc_priv, then set this once in sunxi_mmc_init(), guarded by the
two MACH symbols as above. This would allow an easy transition to being
DT driven later and would prevent us from forgetting about this.

Cheers,
Andre.

> Signed-off-by: Vasily Khoruzhick <anarsoul at gmail.com>
> Signed-off-by: Vagrant Cascadian <vagrant at debian.org>
> ---
> 
>  arch/arm/include/asm/arch-sunxi/mmc.h |  6 +++++-
>  arch/arm/mach-sunxi/Kconfig           |  1 +
>  drivers/mmc/Kconfig                   |  4 ++++
>  drivers/mmc/sunxi_mmc.c               | 20 +++++++++++++++++++-
>  4 files changed, 29 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm/include/asm/arch-sunxi/mmc.h b/arch/arm/include/asm/arch-sunxi/mmc.h
> index d98c53faaa..f2deafddd2 100644
> --- a/arch/arm/include/asm/arch-sunxi/mmc.h
> +++ b/arch/arm/include/asm/arch-sunxi/mmc.h
> @@ -46,7 +46,9 @@ struct sunxi_mmc {
>  	u32 cbda;		/* 0x94 */
>  	u32 res2[26];
>  #if defined(CONFIG_SUNXI_GEN_SUN6I) || defined(CONFIG_MACH_SUN50I_H6)
> -	u32 res3[64];
> +	u32 res3[17];
> +	u32 samp_dl;
> +	u32 res4[46];
>  #endif
>  	u32 fifo;		/* 0x100 / 0x200 FIFO access address */
>  };
> @@ -130,5 +132,7 @@ struct sunxi_mmc {
>  #define SUNXI_MMC_COMMON_CLK_GATE		(1 << 16)
>  #define SUNXI_MMC_COMMON_RESET			(1 << 18)
>  
> +#define SUNXI_MMC_CAL_DL_SW_EN		(0x1 << 7)
> +
>  struct mmc *sunxi_mmc_init(int sdc_no);
>  #endif /* _SUNXI_MMC_H */
> diff --git a/arch/arm/mach-sunxi/Kconfig b/arch/arm/mach-sunxi/Kconfig
> index 686f38fec4..ae77ee9e8e 100644
> --- a/arch/arm/mach-sunxi/Kconfig
> +++ b/arch/arm/mach-sunxi/Kconfig
> @@ -271,6 +271,7 @@ config MACH_SUN50I
>  	bool "sun50i (Allwinner A64)"
>  	select ARM64
>  	select DM_I2C
> +	select MMC_SUNXI_SUPPORTS_CALIBRATION
>  	select PHY_SUN4I_USB
>  	select SUNXI_DE2
>  	select SUNXI_GEN_SUN6I
> diff --git a/drivers/mmc/Kconfig b/drivers/mmc/Kconfig
> index 0a0d4aaf6c..fb8f6697d4 100644
> --- a/drivers/mmc/Kconfig
> +++ b/drivers/mmc/Kconfig
> @@ -569,6 +569,10 @@ config MMC_SUNXI_HAS_NEW_MODE
>  	bool
>  	depends on MMC_SUNXI
>  
> +config MMC_SUNXI_SUPPORTS_CALIBRATION
> +	bool
> +	depends on MMC_SUNXI
> +
>  config GENERIC_ATMEL_MCI
>  	bool "Atmel Multimedia Card Interface support"
>  	depends on DM_MMC && BLK && ARCH_AT91
> diff --git a/drivers/mmc/sunxi_mmc.c b/drivers/mmc/sunxi_mmc.c
> index 39f15eb423..7b064b482c 100644
> --- a/drivers/mmc/sunxi_mmc.c
> +++ b/drivers/mmc/sunxi_mmc.c
> @@ -99,11 +99,15 @@ static int mmc_set_mod_clk(struct sunxi_mmc_priv *priv, unsigned int hz)
>  {
>  	unsigned int pll, pll_hz, div, n, oclk_dly, sclk_dly;
>  	bool new_mode = false;
> +	bool calibrate = false;
>  	u32 val = 0;
>  
>  	if (IS_ENABLED(CONFIG_MMC_SUNXI_HAS_NEW_MODE) && (priv->mmc_no == 2))
>  		new_mode = true;
>  
> +	if (IS_ENABLED(CONFIG_MMC_SUNXI_SUPPORTS_CALIBRATION))
> +		calibrate = true;
> +
>  	/*
>  	 * The MMC clock has an extra /2 post-divider when operating in the new
>  	 * mode.
> @@ -174,7 +178,11 @@ static int mmc_set_mod_clk(struct sunxi_mmc_priv *priv, unsigned int hz)
>  		val = CCM_MMC_CTRL_MODE_SEL_NEW;
>  		setbits_le32(&priv->reg->ntsr, SUNXI_MMC_NTSR_MODE_SEL_NEW);
>  #endif
> -	} else {
> +	} else if (!calibrate) {
> +		/*
> +		 * Use hardcoded delay values if controller doesn't support
> +		 * calibration
> +		 */
>  		val = CCM_MMC_CTRL_OCLK_DLY(oclk_dly) |
>  			CCM_MMC_CTRL_SCLK_DLY(sclk_dly);
>  	}
> @@ -228,6 +236,16 @@ static int mmc_config_clock(struct sunxi_mmc_priv *priv, struct mmc *mmc)
>  	rval &= ~SUNXI_MMC_CLK_DIVIDER_MASK;
>  	writel(rval, &priv->reg->clkcr);
>  
> +#ifdef CONFIG_MMC_SUNXI_SUPPORTS_CALIBRATION
> +	/* A64 supports calibration of delays on MMC controller and we
> +	 * have to set delay of zero before starting calibration.
> +	 * Allwinner BSP driver sets a delay only in the case of
> +	 * using HS400 which is not supported by mainline U-Boot or
> +	 * Linux at the moment
> +	 */
> +	writel(SUNXI_MMC_CAL_DL_SW_EN, &priv->reg->samp_dl);
> +#endif
> +
>  	/* Re-enable Clock */
>  	rval |= SUNXI_MMC_CLK_ENABLE;
>  	writel(rval, &priv->reg->clkcr);
>