Re: [PATCH v4 2/2] scsi: ufs: core: Add support for static TX Equalization settings

[Manivannan Sadhasivam]

On Thu, May 28, 2026 at 03:06:14AM -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>

Reviewed-by: Manivannan Sadhasivam <mani@xxxxxxxxxx>

- Mani

> ---
>  drivers/ufs/core/ufs-txeq.c      |  10 ++-
>  drivers/ufs/host/ufshcd-pltfrm.c | 126 +++++++++++++++++++++++++++++++
>  include/ufs/ufshcd.h             |   2 +
>  3 files changed, 137 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/ufs/core/ufs-txeq.c b/drivers/ufs/core/ufs-txeq.c
> index 4b264adfdf49..b645fe5f6d95 100644
> --- a/drivers/ufs/core/ufs-txeq.c
> +++ b/drivers/ufs/core/ufs-txeq.c
> @@ -1297,7 +1297,13 @@ int ufshcd_config_tx_eq_settings(struct ufs_hba *hba,
>  	}
>  
>  	params = &hba->tx_eq_params[gear - 1];
> -	if (!params->is_valid || force_tx_eqtr) {
> +	/*
> +	 * TX EQTR must run for the following cases:
> +	 * 1. TX EQ settings are invalid.
> +	 * 2. TX EQ settings are valid but static, i.e., populated from DT.
> +	 * 3. TX EQTR procedure is forced.
> +	 */
> +	if (!params->is_valid || params->is_static || force_tx_eqtr) {
>  		int ret;
>  
>  		ret = ufshcd_tx_eqtr(hba, params, pwr_mode);
> @@ -1310,6 +1316,7 @@ 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 +1502,7 @@ static void ufshcd_extract_tx_eq_settings_attrs(struct ufs_hba *hba, u8 gear)
>  	}
>  
>  	params->is_valid = true;
> +	params->is_static = false;
>  }
>  
>  void ufshcd_retrieve_tx_eq_settings(struct ufs_hba *hba)
> diff --git a/drivers/ufs/host/ufshcd-pltfrm.c b/drivers/ufs/host/ufshcd-pltfrm.c
> index c2dafb583cf5..6fe360efa80a 100644
> --- a/drivers/ufs/host/ufshcd-pltfrm.c
> +++ b/drivers/ufs/host/ufshcd-pltfrm.c
> @@ -210,6 +210,130 @@ static void ufshcd_init_lanes_per_dir(struct ufs_hba *hba)
>  	}
>  }
>  
> +static void ufshcd_parse_static_tx_eq_settings(struct ufs_hba *hba)
> +{
> +	size_t sz = hba->lanes_per_direction * 2;
> +	u32 lpd = hba->lanes_per_direction;
> +	struct ufshcd_tx_eq_params *params;
> +	u32 deemphasis[UFS_MAX_LANES * 2];
> +	u32 precode_en[UFS_MAX_LANES * 2];
> +	u32 preshoot[UFS_MAX_LANES * 2];
> +	struct device *dev = hba->dev;
> +	char prop_name[MAX_PROP_SIZE];
> +	int i, err, count, gear, lane;
> +
> +	if (!lpd || lpd > UFS_MAX_LANES)
> +		return;
> +
> +	for (gear = UFS_HS_G1; gear <= UFS_HS_GEAR_MAX; gear++) {
> +		snprintf(prop_name, MAX_PROP_SIZE, "txeq-preshoot-g%d", gear);
> +		count = of_property_count_u32_elems(dev->of_node, prop_name);
> +		if (count <= 0)
> +			continue;
> +
> +		if (count != sz) {
> +			dev_err(dev, "Property %s has invalid count (%d), expecting %zu\n",
> +				prop_name, count, sz);
> +			continue;
> +		}
> +
> +		err = of_property_read_u32_array(dev->of_node, prop_name, preshoot, sz);
> +		if (err) {
> +			dev_err(dev, "Failed to read %s property, %d\n",
> +				prop_name, err);
> +			continue;
> +		}
> +
> +		for (i = 0; i < count; i++) {
> +			if (preshoot[i] >= TX_HS_NUM_PRESHOOT) {
> +				dev_err(dev, "An invalid TX EQ PreShoot (%d) provided in %s property\n",
> +					preshoot[i], prop_name);
> +				break;
> +			}
> +		}
> +
> +		if (i != count)
> +			continue;
> +
> +		snprintf(prop_name, MAX_PROP_SIZE, "txeq-deemphasis-g%d", gear);
> +		count = of_property_count_u32_elems(dev->of_node, prop_name);
> +		if (count <= 0) {
> +			dev_err(dev, "Missing required %s property\n", prop_name);
> +			continue;
> +		}
> +
> +		if (count != sz) {
> +			dev_err(dev, "Property %s has invalid count (%d), expecting %zu\n",
> +				prop_name, count, sz);
> +			continue;
> +		}
> +
> +		err = of_property_read_u32_array(dev->of_node, prop_name, deemphasis, sz);
> +		if (err) {
> +			dev_err(dev, "Failed to read %s property, %d\n",
> +				prop_name, err);
> +			continue;
> +		}
> +
> +		for (i = 0; i < count; i++) {
> +			if (deemphasis[i] >= TX_HS_NUM_DEEMPHASIS) {
> +				dev_err(dev, "An invalid TX EQ DeEmphasis (%d) provided in %s property\n",
> +					deemphasis[i], prop_name);
> +				break;
> +			}
> +		}
> +
> +		if (i != count)
> +			continue;
> +
> +		memset(precode_en, 0, sizeof(precode_en));
> +		if (gear == UFS_HS_G6) {
> +			snprintf(prop_name, MAX_PROP_SIZE, "tx-precode-enable-g%d", gear);
> +			count = of_property_count_u32_elems(dev->of_node, prop_name);
> +			if (count > 0) {
> +				if (count != sz) {
> +					dev_err(dev, "Property %s has invalid count (%d), expecting %zu\n",
> +						prop_name, count, sz);
> +					continue;
> +				}
> +
> +				err = of_property_read_u32_array(dev->of_node, prop_name,
> +								 precode_en, sz);
> +				if (err) {
> +					dev_err(dev, "Failed to read %s property, %d\n",
> +						prop_name, err);
> +					continue;
> +				}
> +
> +				for (i = 0; i < count; i++) {
> +					if (precode_en[i] > 1) {
> +						dev_err(dev, "An invalid PrecodeEn (%d) provided in %s property\n",
> +							precode_en[i], prop_name);
> +						break;
> +					}
> +				}
> +
> +				if (i != count)
> +					continue;
> +			}
> +		}
> +
> +		params = &hba->tx_eq_params[gear - 1];
> +		for (lane = 0; lane < lpd; lane++) {
> +			params->host[lane].preshoot = preshoot[lane * 2];
> +			params->host[lane].deemphasis = deemphasis[lane * 2];
> +			params->host[lane].precode_en = precode_en[lane * 2];
> +
> +			params->device[lane].preshoot = preshoot[lane * 2 + 1];
> +			params->device[lane].deemphasis = deemphasis[lane * 2 + 1];
> +			params->device[lane].precode_en = precode_en[lane * 2 + 1];
> +		}
> +
> +		params->is_valid = true;
> +		params->is_static = true;
> +	}
> +}
> +
>  /**
>   * ufshcd_parse_clock_min_max_freq  - Parse MIN and MAX clocks freq
>   * @hba: per adapter instance
> @@ -528,6 +652,8 @@ int ufshcd_pltfrm_init(struct platform_device *pdev,
>  
>  	ufshcd_init_lanes_per_dir(hba);
>  
> +	ufshcd_parse_static_tx_eq_settings(hba);
> +
>  	err = ufshcd_parse_operating_points(hba);
>  	if (err) {
>  		dev_err(dev, "%s: OPP parse failed %d\n", __func__, err);
> diff --git a/include/ufs/ufshcd.h b/include/ufs/ufshcd.h
> index f48d6416e299..c01824576472 100644
> --- a/include/ufs/ufshcd.h
> +++ b/include/ufs/ufshcd.h
> @@ -359,6 +359,7 @@ struct ufshcd_tx_eqtr_record {
>   * @is_valid: True if parameter contains valid TX Equalization settings
>   * @is_applied: True if settings have been applied to UniPro of both sides
>   * @is_trained: True if parameters obtained from TX EQTR procedure
> + * @is_static: True if settings are static
>   */
>  struct ufshcd_tx_eq_params {
>  	struct ufshcd_tx_eq_settings host[UFS_MAX_LANES];
> @@ -367,6 +368,7 @@ struct ufshcd_tx_eq_params {
>  	bool is_valid;
>  	bool is_applied;
>  	bool is_trained;
> +	bool is_static;
>  };
>  
>  /**
> -- 
> 2.34.1
> 

-- 
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