[PATCH v4 3/4] rockchip: sdhci: Add HS400 Enhanced Strobe support for RK3399

[Jaehoon Chung]

On 1/29/22 07:42, Alper Nebi Yasak wrote:
> On RK3399, a register bit must be set to enable Enhanced Strobe.
> Let the Rockchip SDHCI driver set it when Enhanced Strobe configuration
> is requested. However, having it set makes the lower-speed modes stop
> working and makes reinitialization fail, so let it be unset as needed in
> set_control_reg().
> 
> This is mostly ported from Linux's Arasan SDHCI driver which happens
> to be the underlying IP. (drivers/mmc/host/sdhci-of-arasan.c in Linux
> tree).
> 
> Signed-off-by: Alper Nebi Yasak <alpernebiyasak at gmail.com>

Reviewed-by: Jaehoon Chung <jh80.chung at samsung.com>

Best Regards,
Jaehoon Chung

> ---
> 
> Changes in v4:
> - Add comment for Rockchip SDHCI set_enhanced_strobe() driver data op
> 
> Changes in v2:
> - Unset ES bit in rk3399 set_control_reg() to fix a reinit issue
> - Don't use unnecessary & for function pointer in ops struct
> - Rename rk3399_set_enhanced_strobe -> rk3399_sdhci_set_enhanced_strobe
> - Let set_enhanced_strobe() unset the ES bit if mode is not HS400_ES
> 
>  drivers/mmc/rockchip_sdhci.c | 53 ++++++++++++++++++++++++++++++++++++
>  1 file changed, 53 insertions(+)
> 
> diff --git a/drivers/mmc/rockchip_sdhci.c b/drivers/mmc/rockchip_sdhci.c
> index b91df05de4ff..f4d5a59036a2 100644
> --- a/drivers/mmc/rockchip_sdhci.c
> +++ b/drivers/mmc/rockchip_sdhci.c
> @@ -42,6 +42,9 @@
>  	((((x) >> PHYCTRL_DLLRDY_SHIFT) & PHYCTRL_DLLRDY_MASK) ==\
>  	PHYCTRL_DLLRDY_DONE)
>  
> +#define ARASAN_VENDOR_REGISTER		0x78
> +#define ARASAN_VENDOR_ENHANCED_STROBE	BIT(0)
> +
>  /* Rockchip specific Registers */
>  #define DWCMSHC_EMMC_DLL_CTRL		0x800
>  #define DWCMSHC_EMMC_DLL_CTRL_RESET	BIT(1)
> @@ -117,6 +120,19 @@ struct sdhci_data {
>  	 * Return: 0 if successful, -ve on error
>  	 */
>  	int (*set_ios_post)(struct sdhci_host *host);
> +
> +	/**
> +	 * set_enhanced_strobe() - Set HS400 Enhanced Strobe config
> +	 *
> +	 * This is the set_enhanced_strobe() SDHCI operation that should
> +	 * be used for the hardware this driver data is associated with.
> +	 * Normally, this is used to set any host-specific configuration
> +	 * necessary for HS400 ES.
> +	 *
> +	 * @host: SDHCI host structure
> +	 * Return: 0 if successful, -ve on error
> +	 */
> +	int (*set_enhanced_strobe)(struct sdhci_host *host);
>  };
>  
>  static int rk3399_emmc_phy_init(struct udevice *dev)
> @@ -206,6 +222,21 @@ static int rk3399_emmc_get_phy(struct udevice *dev)
>  	return 0;
>  }
>  
> +static int rk3399_sdhci_set_enhanced_strobe(struct sdhci_host *host)
> +{
> +	struct mmc *mmc = host->mmc;
> +	u32 vendor;
> +
> +	vendor = sdhci_readl(host, ARASAN_VENDOR_REGISTER);
> +	if (mmc->selected_mode == MMC_HS_400_ES)
> +		vendor |= ARASAN_VENDOR_ENHANCED_STROBE;
> +	else
> +		vendor &= ~ARASAN_VENDOR_ENHANCED_STROBE;
> +	sdhci_writel(host, vendor, ARASAN_VENDOR_REGISTER);
> +
> +	return 0;
> +}
> +
>  static void rk3399_sdhci_set_control_reg(struct sdhci_host *host)
>  {
>  	struct rockchip_sdhc *priv = container_of(host, struct rockchip_sdhc, host);
> @@ -217,6 +248,15 @@ static void rk3399_sdhci_set_control_reg(struct sdhci_host *host)
>  		rk3399_emmc_phy_power_off(priv->phy);
>  
>  	sdhci_set_control_reg(host);
> +
> +	/*
> +	 * Reinitializing the device tries to set it to lower-speed modes
> +	 * first, which fails if the Enhanced Strobe bit is set, making
> +	 * the device impossible to use. Set the correct value here to
> +	 * let reinitialization attempts succeed.
> +	 */
> +	if (CONFIG_IS_ENABLED(MMC_HS400_ES_SUPPORT))
> +		rk3399_sdhci_set_enhanced_strobe(host);
>  };
>  
>  static int rk3399_sdhci_set_ios_post(struct sdhci_host *host)
> @@ -409,10 +449,22 @@ static int rockchip_sdhci_execute_tuning(struct mmc *mmc, u8 opcode)
>  	return ret;
>  }
>  
> +static int rockchip_sdhci_set_enhanced_strobe(struct sdhci_host *host)
> +{
> +	struct rockchip_sdhc *priv = container_of(host, struct rockchip_sdhc, host);
> +	struct sdhci_data *data = (struct sdhci_data *)dev_get_driver_data(priv->dev);
> +
> +	if (data->set_enhanced_strobe)
> +		return data->set_enhanced_strobe(host);
> +
> +	return -ENOTSUPP;
> +}
> +
>  static struct sdhci_ops rockchip_sdhci_ops = {
>  	.set_ios_post	= rockchip_sdhci_set_ios_post,
>  	.platform_execute_tuning = &rockchip_sdhci_execute_tuning,
>  	.set_control_reg = rockchip_sdhci_set_control_reg,
> +	.set_enhanced_strobe = rockchip_sdhci_set_enhanced_strobe,
>  };
>  
>  static int rockchip_sdhci_probe(struct udevice *dev)
> @@ -495,6 +547,7 @@ static const struct sdhci_data rk3399_data = {
>  	.emmc_phy_init = rk3399_emmc_phy_init,
>  	.set_control_reg = rk3399_sdhci_set_control_reg,
>  	.set_ios_post = rk3399_sdhci_set_ios_post,
> +	.set_enhanced_strobe = rk3399_sdhci_set_enhanced_strobe,
>  };
>  
>  static const struct sdhci_data rk3568_data = {