[PATCH 2/4] mmc: mtk-sd: add default tuning parameters for mt7620
AngeloGioacchino Del Regno
angelogioacchino.delregno at collabora.com
Mon Jun 23 02:57:01 PDT 2025
Il 19/06/25 07:35, Shiji Yang ha scritto:
> The MIPS MT762x SoCs require some specific tuning parameters at
> different clock frequencies. These legacy SoCs only support max
> 48~50 MHz High-Speed SD mode. Therefore, the standard tuning step
> is not available. We have to hardcode these tuning parameters to
> make them work properly.
>
> Signed-off-by: Shiji Yang <yangshiji66 at outlook.com>
> ---
> drivers/mmc/host/mtk-sd.c | 18 +++++++++++++++++-
> 1 file changed, 17 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/mtk-sd.c b/drivers/mmc/host/mtk-sd.c
> index 53d63bb4e..52198daef 100644
> --- a/drivers/mmc/host/mtk-sd.c
> +++ b/drivers/mmc/host/mtk-sd.c
> @@ -79,6 +79,8 @@
> #define MSDC_PATCH_BIT2 0xb8
> #define MSDC_PAD_TUNE 0xec
> #define MSDC_PAD_TUNE0 0xf0
> +#define MSDC_DAT_RDDLY0 0xf0
> +#define MSDC_DAT_RDDLY1 0xf4
> #define PAD_DS_TUNE 0x188
> #define PAD_CMD_TUNE 0x18c
> #define EMMC51_CFG0 0x204
> @@ -449,6 +451,7 @@ struct mtk_mmc_compatible {
> bool use_internal_cd;
> bool support_new_tx;
> bool support_new_rx;
> + bool mips_mt762x;
> };
>
> struct msdc_tune_para {
> @@ -595,6 +598,7 @@ static const struct mtk_mmc_compatible mt7620_compat = {
> .enhance_rx = false,
> .support_cmd23 = false,
> .use_internal_cd = true,
> + .mips_mt762x = true,
No, you can't do that - this needs to be done in a clean manner.
Please map that to something that makes sense, as in, add the register definitions
and add something like...
.tune_para = {
.tune0_rval = FIELD_PREP_CONST(MSDC_PAD_TUNE_DATWRDLY, 16) |
FIELD_PREP_CONST(MSDC_PAD_TUNE_DATRDDLY, 16) |
FIELD_PREP_CONST(MSDC_PAD_TUNE_CMDRDLY, 16) |
FIELD_PREP_CONST(MSDC_PAD_TUNE_CMDRRDLY, 4) |
FIELD_PREP_CONST(MSDC_PAD_TUNE_CLKTDLY, 10),
.rddly0_rval = etc etc etc :-)
};
...then, check if .tune_para is present: if it is, apply the static settings,
otherwise, don't.
Cheers,
Angelo
> };
>
> static const struct mtk_mmc_compatible mt7622_compat = {
> @@ -1090,7 +1094,12 @@ static void msdc_set_mclk(struct msdc_host *host, unsigned char timing, u32 hz)
> * mmc_select_hs400() will drop to 50Mhz and High speed mode,
> * tune result of hs200/200Mhz is not suitable for 50Mhz
> */
> - if (mmc->actual_clock <= 52000000) {
> + if (host->dev_comp->mips_mt762x &&
> + mmc->actual_clock > 25000000) {
> + sdr_set_bits(host->base + MSDC_IOCON, MSDC_IOCON_RSPL);
> + sdr_set_bits(host->base + MSDC_IOCON, MSDC_IOCON_DSPL);
> + sdr_set_bits(host->base + MSDC_IOCON, MSDC_IOCON_W_DSPL);
> + } else if (mmc->actual_clock <= 52000000) {
> writel(host->def_tune_para.iocon, host->base + MSDC_IOCON);
> if (host->top_base) {
> writel(host->def_tune_para.emmc_top_control,
> @@ -2028,6 +2037,13 @@ static void msdc_init_hw(struct msdc_host *host)
> MSDC_PAD_TUNE_RXDLYSEL);
> }
>
> + if (host->dev_comp->mips_mt762x) {
> + /* Set default tuning parameters */
> + writel(0x84101010, host->base + tune_reg);
> + writel(0x10101010, host->base + MSDC_DAT_RDDLY0);
> + writel(0x10101010, host->base + MSDC_DAT_RDDLY1);
> + }
> +
> if (mmc->caps2 & MMC_CAP2_NO_SDIO) {
> sdr_clr_bits(host->base + SDC_CFG, SDC_CFG_SDIO);
> sdr_clr_bits(host->base + MSDC_INTEN, MSDC_INTEN_SDIOIRQ);
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