Re: [U-Boot] [PATCH] mmc: fsl_esdhc: Add support for DDR mode

[Pantelis Antoniou]

Hi Volodymyr,

> On Jan 14, 2015, at 22:46 , Volodymyr Riazantsev 
> <volodymyr.riazant...@globallogic.com> wrote:
> 
> Add support of the DDR mode for eSDHC driver.
> Enable it for i.MX6 SoC family only.
> 
> Change-Id: Ie27a945c9fe79d044cc886e269b60747f1744116
> Signed-off-by: Volodymyr Riazantsev <volodymyr.riazant...@globallogic.com>
> ---
> drivers/mmc/fsl_esdhc.c | 8 ++++++--
> include/fsl_esdhc.h     | 1 +
> 2 files changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/mmc/fsl_esdhc.c b/drivers/mmc/fsl_esdhc.c
> index c55eb28..abec45f 100644
> --- a/drivers/mmc/fsl_esdhc.c
> +++ b/drivers/mmc/fsl_esdhc.c
> @@ -319,7 +319,8 @@ esdhc_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd, 
> struct mmc_data *data)
>       esdhc_write32(&regs->cmdarg, cmd->cmdarg);
> #if defined(CONFIG_FSL_USDHC)
>       esdhc_write32(&regs->mixctrl,
> -     (esdhc_read32(&regs->mixctrl) & 0xFFFFFF80) | (xfertyp & 0x7F));
> +     (esdhc_read32(&regs->mixctrl) & 0xFFFFFF80) | (xfertyp & 0x7F)
> +                     | (mmc->ddr_mode ? XFERTYP_DDREN : 0));
>       esdhc_write32(&regs->xfertyp, xfertyp & 0xFFFF0000);
> #else
>       esdhc_write32(&regs->xfertyp, xfertyp);
> @@ -442,7 +443,7 @@ static void set_sysctl(struct mmc *mmc, uint clock)
>               if ((sdhc_clk / (div * pre_div)) <= clock)
>                       break;
> 
> -     pre_div >>= 1;
> +     pre_div >>= mmc->ddr_mode ? 2 : 1;
>       div -= 1;
> 
>       clk = (pre_div << 8) | (div << 4);
> @@ -601,6 +602,9 @@ int fsl_esdhc_initialize(bd_t *bis, struct fsl_esdhc_cfg 
> *cfg)
>       }
> 
>       cfg->cfg.host_caps = MMC_MODE_4BIT | MMC_MODE_8BIT | MMC_MODE_HC;
> +#ifdef CONFIG_MX6
> +     cfg->cfg.host_caps |= MMC_MODE_DDR_52MHz;
> +#endif
> 
>       if (cfg->max_bus_width > 0) {
>               if (cfg->max_bus_width < 8)
> diff --git a/include/fsl_esdhc.h b/include/fsl_esdhc.h
> index c1b6648..313fa1e 100644
> --- a/include/fsl_esdhc.h
> +++ b/include/fsl_esdhc.h
> @@ -108,6 +108,7 @@
> #define XFERTYP_RSPTYP_48_BUSY        0x00030000
> #define XFERTYP_MSBSEL                0x00000020
> #define XFERTYP_DTDSEL                0x00000010
> +#define XFERTYP_DDREN                0x00000008
> #define XFERTYP_AC12EN                0x00000004
> #define XFERTYP_BCEN          0x00000002
> #define XFERTYP_DMAEN         0x00000001
> -- 
> 2.2.0

The patch is OK, but I don’t like the use of CONFIG_MX6 for enabling it.
The meaning is that the MMC IP block in MX6 supports DDR mode, so make it a 
quirk
that’s enabled for MX6.

Subsequent SoCs might use the same mode, so I don’t like having to do endless 
defines
of SoC families.

Please rework.

Regards

— Pantelis

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