Re: [PATCH 5/5] scsi: ufs: mediatek: Rework resets

[Philipp Zabel <p.zabel@pengutronix.de>]

Hi Nicolas,

On Di, 2025-10-14 at 17:10 +0200, Nicolas Frattaroli wrote:
> Rework the reset control getting in the driver's probe function to use
> the "_optional" function instead of defaulting to NULL on IS_ERR, so
> that actual real errors (as opposed to missing resets) can be handled as
> errors in the probe function.
> 
> Also move the MPHY reset into the PHY driver, where it should live, and
> remove all remnants of it ever having been in this driver.

Part of that happened in the previous patch.

> Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
> ---
>  drivers/ufs/host/ufs-mediatek-sip.h |  8 -----
>  drivers/ufs/host/ufs-mediatek.c     | 67 +++++++++++++++++++++----------------
>  drivers/ufs/host/ufs-mediatek.h     |  1 -
>  3 files changed, 38 insertions(+), 38 deletions(-)
> 
> diff --git a/drivers/ufs/host/ufs-mediatek-sip.h b/drivers/ufs/host/ufs-mediatek-sip.h
> index d627dfb4a766..256598cc3b5b 100644
> --- a/drivers/ufs/host/ufs-mediatek-sip.h
> +++ b/drivers/ufs/host/ufs-mediatek-sip.h
> @@ -31,11 +31,6 @@ enum ufs_mtk_vcc_num {
>  	UFS_VCC_MAX
>  };
>  
> -enum ufs_mtk_mphy_op {
> -	UFS_MPHY_BACKUP = 0,
> -	UFS_MPHY_RESTORE
> -};
> -
>  /*
>   * SMC call wrapper function
>   */
> @@ -84,9 +79,6 @@ static inline void _ufs_mtk_smc(struct ufs_mtk_smc_arg s)
>  #define ufs_mtk_device_pwr_ctrl(on, ufs_version, res) \
>  	ufs_mtk_smc(UFS_MTK_SIP_DEVICE_PWR_CTRL, &(res), on, ufs_version)
>  
> -#define ufs_mtk_mphy_ctrl(op, res) \
> -	ufs_mtk_smc(UFS_MTK_SIP_MPHY_CTRL, &(res), op)
> -
>  #define ufs_mtk_mtcmos_ctrl(op, res) \
>  	ufs_mtk_smc(UFS_MTK_SIP_MTCMOS_CTRL, &(res), op)
>  
> diff --git a/drivers/ufs/host/ufs-mediatek.c b/drivers/ufs/host/ufs-mediatek.c
> index 758a393a9de1..ac40d4a3a800 100644
> --- a/drivers/ufs/host/ufs-mediatek.c
> +++ b/drivers/ufs/host/ufs-mediatek.c
> @@ -204,49 +204,60 @@ static void ufs_mtk_crypto_enable(struct ufs_hba *hba)
>  static void ufs_mtk_host_reset(struct ufs_hba *hba)
>  {
>  	struct ufs_mtk_host *host = ufshcd_get_variant(hba);
> -	struct arm_smccc_res res;
> +	int ret;
>  
>  	reset_control_assert(host->hci_reset);
>  	reset_control_assert(host->crypto_reset);
>  	reset_control_assert(host->unipro_reset);
> -	reset_control_assert(host->mphy_reset);
>  
> -	usleep_range(100, 110);
> +	ret = phy_reset(host->mphy);
> +
> +	/*
> +	 * Only sleep if MPHY doesn't have a reset implemented (which already
> +	 * sleeps) or the PHY reset function failed somehow, just to be safe
> +	 */
> +	if (ret) {
> +		usleep_range(100, 110);
> +		if (ret != -EOPNOTSUPP)
> +			dev_warn(hba->dev, "PHY reset failed: %pe\n", ERR_PTR(ret));
> +	}
>  
>  	reset_control_deassert(host->unipro_reset);
>  	reset_control_deassert(host->crypto_reset);
>  	reset_control_deassert(host->hci_reset);
> -	reset_control_deassert(host->mphy_reset);
> -
> -	/* restore mphy setting aftre mphy reset */
> -	if (host->mphy_reset)
> -		ufs_mtk_mphy_ctrl(UFS_MPHY_RESTORE, res);
>  }
>  
> -static void ufs_mtk_init_reset_control(struct ufs_hba *hba,
> -				       struct reset_control **rc,
> -				       char *str)
> +static int ufs_mtk_init_reset_control(struct ufs_hba *hba,
> +				      struct reset_control **rc,
> +				      const char *str)
>  {
> -	*rc = devm_reset_control_get(hba->dev, str);
> +	*rc = devm_reset_control_get_optional(hba->dev, str);

Please use

	devm_reset_control_get_optional_exclusive()

directly, or see below for an alternative suggestion.

>  	if (IS_ERR(*rc)) {
> -		dev_info(hba->dev, "Failed to get reset control %s: %ld\n",
> -			 str, PTR_ERR(*rc));
> -		*rc = NULL;
> +		dev_err(hba->dev, "Failed to get reset control %s: %pe\n", str, *rc);
> +		return PTR_ERR(*rc);
>  	}
> +
> +	return 0;
>  }
>  
> -static void ufs_mtk_init_reset(struct ufs_hba *hba)
> +static int ufs_mtk_init_reset(struct ufs_hba *hba)
>  {
>  	struct ufs_mtk_host *host = ufshcd_get_variant(hba);
> +	int ret;
> +
> +	ret = ufs_mtk_init_reset_control(hba, &host->hci_reset, "hci_rst");
> +	if (ret)
> +		return ret;
> +
> +	ret = ufs_mtk_init_reset_control(hba, &host->unipro_reset, "unipro_rst");
> +	if (ret)
> +		return ret;
> +
> +	ret = ufs_mtk_init_reset_control(hba, &host->crypto_reset, "crypto_rst");
> +	if (ret)
> +		return ret;

It looks to me like you could combine these into a

	devm_reset_control_bulk_get_optional_exclusive()

and operate the three resets with reset_control_bulk_assert/deassert().


regards
Philipp