RE: [PATCH v19 05/12] mmc: renesas_sdhi: Add tuning delay support for RZ/G2L

[Biju Das]

Hi All,

> -----Original Message-----
> From: Biju <biju.das.au@xxxxxxxxx>
> Sent: 09 July 2026 20:29
> Subject: [PATCH v19 05/12] mmc: renesas_sdhi: Add tuning delay support for RZ/G2L
> 
> From: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
> 
> Some SoCs, starting with RZ/G2L, require a hardware adjustment delay to be written to SCC_TMPPORT2 when
> switching signal voltage during tuning. The register value differs by voltage: 0x1 for 1.8 V and 0x0 for
> 3.3 V.
> 
> Introduce TMIO_MMC_TUNING_DELAY flag (bit 13) in tmio.h to identify controllers that need this behaviour.
> Add renesas_sdhi_set_hw_adjustment_delay(), which writes the appropriate value to SCC_TMPPORT2 when the
> flag is set, and call it from
> renesas_sdhi_start_signal_voltage_switch() after the regulator is configured. Additionally, reset
> SCC_TMPPORT2 to 0 at the start of
> renesas_sdhi_execute_tuning() when the flag is set and tap_num is 8.
> 
> Introduce a dedicated of_data_rz_g2l descriptor carrying the new flag alongside RZ/G2L-specific
> capabilities, and wire of_rzg2l_compatible to it instead of the generic R-Car Gen3 descriptor.
> 
> Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
> ---
> v18->v19:
>  * No change.
> v18:
>  * New patch.
> ---
>  drivers/mmc/host/renesas_sdhi_core.c          | 86 +++++++++++--------
>  drivers/mmc/host/renesas_sdhi_internal_dmac.c | 21 ++++-
>  include/linux/platform_data/tmio.h            |  3 +
>  3 files changed, 75 insertions(+), 35 deletions(-)
> 
> diff --git a/drivers/mmc/host/renesas_sdhi_core.c b/drivers/mmc/host/renesas_sdhi_core.c
> index 5c478995d660..832a7a7be725 100644
> --- a/drivers/mmc/host/renesas_sdhi_core.c
> +++ b/drivers/mmc/host/renesas_sdhi_core.c
> @@ -256,40 +256,6 @@ static int renesas_sdhi_card_busy(struct mmc_host *mmc)
>  		 TMIO_STAT_DAT0);
>  }
> 
> -static int renesas_sdhi_start_signal_voltage_switch(struct mmc_host *mmc,
> -						    struct mmc_ios *ios)
> -{
> -	struct tmio_mmc_host *host = mmc_priv(mmc);
> -	struct renesas_sdhi *priv = host_to_priv(host);
> -	struct pinctrl_state *pin_state;
> -	int ret;
> -
> -	switch (ios->signal_voltage) {
> -	case MMC_SIGNAL_VOLTAGE_330:
> -		pin_state = priv->pins_default;
> -		break;
> -	case MMC_SIGNAL_VOLTAGE_180:
> -		pin_state = priv->pins_uhs;
> -		break;
> -	default:
> -		return -EINVAL;
> -	}
> -
> -	/*
> -	 * If anything is missing, assume signal voltage is fixed at
> -	 * 3.3V and succeed/fail accordingly.
> -	 */
> -	if (IS_ERR(priv->pinctrl) || IS_ERR(pin_state))
> -		return ios->signal_voltage ==
> -			MMC_SIGNAL_VOLTAGE_330 ? 0 : -EINVAL;
> -
> -	ret = mmc_regulator_set_vqmmc(host->mmc, ios);
> -	if (ret < 0)
> -		return ret;
> -
> -	return pinctrl_select_state(priv->pinctrl, pin_state);
> -}
> -
>  /* SCC registers */
>  #define SH_MOBILE_SDHI_SCC_DTCNTL	0x000
>  #define SH_MOBILE_SDHI_SCC_TAPSET	0x002
> @@ -350,6 +316,55 @@ static inline void sd_scc_write32(struct tmio_mmc_host *host,
>  	writel(val, priv->scc_ctl + (addr << host->bus_shift));  }
> 
> +static void renesas_sdhi_set_hw_adjustment_delay(struct tmio_mmc_host
> +*host) {
> +	struct renesas_sdhi *priv = host_to_priv(host);
> +
> +	if (!(host->pdata->flags & TMIO_MMC_TUNING_DELAY))
> +		return;
> +
> +	if (host->mmc->ios.signal_voltage == MMC_SIGNAL_VOLTAGE_330)
> +		sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_TMPPORT2, 0x0);
> +	else
> +		sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_TMPPORT2, 0x1);

Looks sashiko's comment is false positive as after the tuning only we set HS400
registers. So it it is safe to unconditional writes here.

[1] https://sashiko.dev/#/patchset/20260709192916.630794-1-biju.das.jz%40bp.renesas.com

 }
> +
> +static int renesas_sdhi_start_signal_voltage_switch(struct mmc_host *mmc,
> +						    struct mmc_ios *ios)
> +{
> +	struct tmio_mmc_host *host = mmc_priv(mmc);
> +	struct renesas_sdhi *priv = host_to_priv(host);
> +	struct pinctrl_state *pin_state;
> +	int ret;
> +
> +	switch (ios->signal_voltage) {
> +	case MMC_SIGNAL_VOLTAGE_330:
> +		pin_state = priv->pins_default;
> +		break;
> +	case MMC_SIGNAL_VOLTAGE_180:
> +		pin_state = priv->pins_uhs;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	/*
> +	 * If anything is missing, assume signal voltage is fixed at
> +	 * 3.3V and succeed/fail accordingly.
> +	 */
> +	if (IS_ERR(priv->pinctrl) || IS_ERR(pin_state))
> +		return ios->signal_voltage ==
> +			MMC_SIGNAL_VOLTAGE_330 ? 0 : -EINVAL;
> +
> +	ret = mmc_regulator_set_vqmmc(host->mmc, ios);
> +	if (ret < 0)
> +		return ret;
> +
> +	renesas_sdhi_set_hw_adjustment_delay(host);
> +
> +	return pinctrl_select_state(priv->pinctrl, pin_state); }
> +
>  static unsigned int renesas_sdhi_init_tuning(struct tmio_mmc_host *host)  {
>  	struct renesas_sdhi *priv;
> @@ -709,6 +724,9 @@ static int renesas_sdhi_execute_tuning(struct mmc_host *mmc, u32 opcode)
>  	if (!priv->tap_num)
>  		return 0; /* Tuning is not supported */
> 
> +	if ((host->pdata->flags & TMIO_MMC_TUNING_DELAY) && priv->tap_num == 8)
> +		sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_TMPPORT2, 0);

Same here.

Cheers,
Biju

> +
>  	if (priv->tap_num * 2 >= sizeof(priv->taps) * BITS_PER_BYTE) {
>  		dev_err(&host->pdev->dev,
>  			"Too many taps, please update 'taps' in tmio_mmc_host!\n"); diff --git
> a/drivers/mmc/host/renesas_sdhi_internal_dmac.c b/drivers/mmc/host/renesas_sdhi_internal_dmac.c
> index 2bf354331b2d..8476678d47a6 100644
> --- a/drivers/mmc/host/renesas_sdhi_internal_dmac.c
> +++ b/drivers/mmc/host/renesas_sdhi_internal_dmac.c
> @@ -142,6 +142,25 @@ static const struct renesas_sdhi_of_data of_data_rcar_gen3_no_sdh_fallback = {
>  	.max_divider	= SDHI_MAX_DIVIDER_DEFAULT,
>  };
> 
> +static const struct renesas_sdhi_of_data of_data_rz_g2l = {
> +	.tmio_flags	= TMIO_MMC_HAS_IDLE_WAIT | TMIO_MMC_CLK_ACTUAL |
> +			  TMIO_MMC_HAVE_CBSY | TMIO_MMC_MIN_RCAR2 |
> +			  TMIO_MMC_64BIT_DATA_PORT | TMIO_MMC_TUNING_DELAY,
> +	.capabilities	= MMC_CAP_SD_HIGHSPEED | MMC_CAP_SDIO_IRQ |
> +			  MMC_CAP_CMD23 | MMC_CAP_WAIT_WHILE_BUSY,
> +	.capabilities2	= MMC_CAP2_NO_WRITE_PROTECT | MMC_CAP2_MERGE_CAPABLE,
> +	.bus_shift	= 2,
> +	.scc_offset	= 0x1000,
> +	.taps		= rcar_gen3_scc_taps,
> +	.taps_num	= ARRAY_SIZE(rcar_gen3_scc_taps),
> +	/* DMAC can handle 32bit blk count but only 1 segment */
> +	.max_blk_count	= UINT_MAX / TMIO_MAX_BLK_SIZE,
> +	.max_segs	= 1,
> +	.sdhi_flags	= SDHI_FLAG_NEED_CLKH_FALLBACK,
> +	.clk_mask	= SDHI_CLK_MASK_DEFAULT,
> +	.max_divider	= SDHI_MAX_DIVIDER_DEFAULT,
> +};
> +
>  static const u8 r8a7796_es13_calib_table[2][SDHI_CALIB_TABLE_MAX] = {
>  	{ 3,  3,  3,  3,  3,  3,  3,  4,  4,  5,  6,  7,  8,  9, 10, 15,
>  	 16, 16, 16, 16, 16, 16, 17, 18, 18, 19, 20, 21, 22, 23, 24, 25 }, @@ -263,7 +282,7 @@ static
> const struct renesas_sdhi_of_data_with_quirks of_r8a77990_compatible = {  };
> 
>  static const struct renesas_sdhi_of_data_with_quirks of_rzg2l_compatible = {
> -	.of_data = &of_data_rcar_gen3,
> +	.of_data = &of_data_rz_g2l,
>  	.quirks = &sdhi_quirks_rzg2l,
>  };
> 
> diff --git a/include/linux/platform_data/tmio.h b/include/linux/platform_data/tmio.h
> index 27ea21c00419..868a21842fa5 100644
> --- a/include/linux/platform_data/tmio.h
> +++ b/include/linux/platform_data/tmio.h
> @@ -50,6 +50,9 @@
>  /* Some controllers have a 64-bit wide data port register */
>  #define TMIO_MMC_64BIT_DATA_PORT	BIT(12)
> 
> +/* Some controllers have tuning delay */
> +#define TMIO_MMC_TUNING_DELAY		BIT(13)
> +
>  struct tmio_mmc_data {
>  	void				*chan_priv_tx;
>  	void				*chan_priv_rx;
> --
> 2.43.0