[PATCH 3/3] rockchip: sdhci: Add HS400 Enhanced Strobe support for RK3568

[Jaehoon Chung]

On 11/1/21 6:07 PM, Alper Nebi Yasak wrote:
> On RK3568, a register bit must be set to enable Enhanced Strobe.
> However, it appears that the address of this register may differ from
> vendor to vendor and should be read from the underlying MMC IP.
> Let the Rockchip SDHCI driver read this address and set the relevant bit
> when Enhanced Strobe configuration is requested.
> 
> This is mostly ported from Linux' Synopsys DWC MSHC driver which happens
> to be the underlying IP. (drivers/mmc/host/sdhci-of-dwcmshc.c in Linux
> tree).
> 
> Signed-off-by: Alper Nebi Yasak <alpernebiyasak at gmail.com>
> ---
> Merely build-tested as I don't have a RK3568 board.

If someone can test this patch on RK3568 board, it will be more better.

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

Best Regards,
Jaehoon Chung

> 
>  drivers/mmc/rockchip_sdhci.c | 23 +++++++++++++++++++++++
>  1 file changed, 23 insertions(+)
> 
> diff --git a/drivers/mmc/rockchip_sdhci.c b/drivers/mmc/rockchip_sdhci.c
> index 7457255fa080..c95f95578672 100644
> --- a/drivers/mmc/rockchip_sdhci.c
> +++ b/drivers/mmc/rockchip_sdhci.c
> @@ -45,6 +45,13 @@
>  #define ARASAN_VENDOR_REGISTER		0x78
>  #define ARASAN_VENDOR_ENHANCED_STROBE	BIT(0)
>  
> +/* DWC IP vendor area 1 pointer */
> +#define DWCMSHC_P_VENDOR_AREA1		0xe8
> +#define DWCMSHC_AREA1_MASK		GENMASK(11, 0)
> +/* Offset inside the vendor area 1 */
> +#define DWCMSHC_EMMC_CONTROL		0x2c
> +#define DWCMSHC_ENHANCED_STROBE		BIT(8)
> +
>  /* Rockchip specific Registers */
>  #define DWCMSHC_EMMC_DLL_CTRL		0x800
>  #define DWCMSHC_EMMC_DLL_CTRL_RESET	BIT(1)
> @@ -284,6 +291,21 @@ static int rk3568_emmc_get_phy(struct udevice *dev)
>  	return 0;
>  }
>  
> +static int rk3568_set_enhanced_strobe(struct sdhci_host *host)
> +{
> +	u32 vendor;
> +	int reg;
> +
> +	reg = (sdhci_readl(host, DWCMSHC_P_VENDOR_AREA1) & DWCMSHC_AREA1_MASK)
> +	      + DWCMSHC_EMMC_CONTROL;
> +
> +	vendor = sdhci_readl(host, reg);
> +	vendor |= DWCMSHC_ENHANCED_STROBE;
> +	sdhci_writel(host, vendor, reg);
> +
> +	return 0;
> +}
> +
>  static int rockchip_sdhci_set_ios_post(struct sdhci_host *host)
>  {
>  	struct rockchip_sdhc *priv = container_of(host, struct rockchip_sdhc, host);
> @@ -473,6 +495,7 @@ static const struct sdhci_data rk3568_data = {
>  	.emmc_set_clock = rk3568_sdhci_emmc_set_clock,
>  	.get_phy = rk3568_emmc_get_phy,
>  	.emmc_phy_init = rk3568_emmc_phy_init,
> +	.set_enhanced_strobe = rk3568_set_enhanced_strobe,
>  };
>  
>  static const struct udevice_id sdhci_ids[] = {
>