[PATCH 2/3] rockchip: sdhci: Add HS400 Enhanced Strobe support for RK3399

[Jaehoon Chung]

On 11/1/21 6:07 PM, 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.
> 
> This is mostly ported from Linux' 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

> ---
> 
>  drivers/mmc/rockchip_sdhci.c | 28 ++++++++++++++++++++++++++++
>  1 file changed, 28 insertions(+)
> 
> diff --git a/drivers/mmc/rockchip_sdhci.c b/drivers/mmc/rockchip_sdhci.c
> index 278473899c7c..7457255fa080 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)
> @@ -93,6 +96,7 @@ struct sdhci_data {
>  	int (*emmc_set_clock)(struct sdhci_host *host, unsigned int clock);
>  	int (*emmc_phy_init)(struct udevice *dev);
>  	int (*get_phy)(struct udevice *dev);
> +	int (*set_enhanced_strobe)(struct sdhci_host *host);
>  };
>  
>  static int rk3399_emmc_phy_init(struct udevice *dev)
> @@ -198,6 +202,17 @@ static int rk3399_sdhci_emmc_set_clock(struct sdhci_host *host, unsigned int clo
>  	return 0;
>  }
>  
> +static int rk3399_set_enhanced_strobe(struct sdhci_host *host)
> +{
> +	u32 vendor;
> +
> +	vendor = sdhci_readl(host, ARASAN_VENDOR_REGISTER);
> +	vendor |= ARASAN_VENDOR_ENHANCED_STROBE;
> +	sdhci_writel(host, vendor, ARASAN_VENDOR_REGISTER);
> +
> +	return 0;
> +}
> +
>  static int rk3568_emmc_phy_init(struct udevice *dev)
>  {
>  	struct rockchip_sdhc *prv = dev_get_priv(dev);
> @@ -355,9 +370,21 @@ 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_enhanced_strobe = &rockchip_sdhci_set_enhanced_strobe,
>  };
>  
>  static int rockchip_sdhci_probe(struct udevice *dev)
> @@ -439,6 +466,7 @@ static const struct sdhci_data rk3399_data = {
>  	.emmc_set_clock = rk3399_sdhci_emmc_set_clock,
>  	.get_phy = rk3399_emmc_get_phy,
>  	.emmc_phy_init = rk3399_emmc_phy_init,
> +	.set_enhanced_strobe = rk3399_set_enhanced_strobe,
>  };
>  
>  static const struct sdhci_data rk3568_data = {
>