Re: [PATCH 2/2] scsi: ufs: core: Add support for static TX Equalization settings

[Manivannan Sadhasivam]

On Wed, May 27, 2026 at 07:40:55AM -0700, Can Guo wrote:
> Static TX Equalization settings and TX Precode enable indication from DT
> properties txeq-preshoot-g[1-6], txeq-deemphasis-g[1-6], and
> tx-precode-enable-g6 are board-specific baseline values. Values are
> provided as per-lane tuples:
> 
> <Host_Lane0 Device_Lane0>, [<Host_Lane1 Device_Lane1>]
> 
> Parse DT u32 properties with explicit range checks by using
> of_property_count_u32_elems()/of_property_read_u32_array().
> 
> When adaptive TX Equalization is used, these static settings are not final:
> 
> - If valid settings are retrieved from qTxEQGnSettings/wTxEQGnSettingsExt,
>   those retrieved settings override static DT settings.
> - If retrieval is not available/valid, TX EQTR runs and trained settings
>   override static DT settings.
> 
> So static DT settings are a fallback and are intended for cases where
> adaptive TX Equalization is not enabled/used. Adaptive TX Equalization
> remains the primary path when enabled.
> 
> No behavior changes for platforms that do not provide these properties.
> 
> Signed-off-by: Can Guo <can.guo@xxxxxxxxxxxxxxxx>
> ---
>  drivers/ufs/core/ufs-txeq.c      |   4 +-
>  drivers/ufs/host/ufshcd-pltfrm.c | 128 +++++++++++++++++++++++++++++++
>  include/ufs/ufshcd.h             |   2 +
>  3 files changed, 133 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/ufs/core/ufs-txeq.c b/drivers/ufs/core/ufs-txeq.c
> index 4b264adfdf49..634ec039e129 100644
> --- a/drivers/ufs/core/ufs-txeq.c
> +++ b/drivers/ufs/core/ufs-txeq.c
> @@ -1297,7 +1297,7 @@ int ufshcd_config_tx_eq_settings(struct ufs_hba *hba,
>  	}
>  
>  	params = &hba->tx_eq_params[gear - 1];
> -	if (!params->is_valid || force_tx_eqtr) {
> +	if (!params->is_valid || params->is_static || force_tx_eqtr) {
>  		int ret;
>  
>  		ret = ufshcd_tx_eqtr(hba, params, pwr_mode);
> @@ -1310,6 +1310,7 @@ int ufshcd_config_tx_eq_settings(struct ufs_hba *hba,
>  		/* Mark TX Equalization settings as valid */
>  		params->is_valid = true;
>  		params->is_trained = true;
> +		params->is_static = false;
>  		params->is_applied = false;
>  	}
>  
> @@ -1495,6 +1496,7 @@ static void ufshcd_extract_tx_eq_settings_attrs(struct ufs_hba *hba, u8 gear)
>  	}
>  
>  	params->is_valid = true;
> +	params->is_static = false;

Maybe it's me, but I'm not able to understand how you want to apply these static
EQ settings. In commit message you said, the static values should be used as a
fallback, but you just check for 'params->is_static' while triggering
ufshcd_tx_eqtr() which is supposed to perform adaptive TX EQ training. IMO, you
don't need any check at all for applying static setting. If '(!params->is_valid
|| force_tx_eqtr)' condition is not satisfied, then the static setting should be
used.

- Mani

-- 
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