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

[Can Guo <can.guo@oss.qualcomm.com>]

On 5/28/2026 2:18 PM, Manivannan Sadhasivam wrote:
> 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@oss.qualcomm.com>
>> ---
>>   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;
>>   }
>>   
>>   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..2db2103a6ac0 100644
>> --- a/drivers/ufs/host/ufshcd-pltfrm.c
>> +++ b/drivers/ufs/host/ufshcd-pltfrm.c
>> @@ -210,6 +210,132 @@ 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) {
>> +		dev_err(dev, "Invalid lanes-per-direction value (%u) provided\n", lpd);
>> +		return;
>> +	}
>> +
> 'lanes_per_direction' can be 0 for platforms that do not support deriving the
> lanes count from DT:
>
> https://lore.kernel.org/linux-scsi/20260520070009epcms2p6542f3abb7660839e9d8140b3f2f145c3@epcms2p6/
>
> You should just drop the err message to avoid spamming those platforms.
Good catch! Will do in next version.

Thanks,
Can Guo.
>
> - Mani
>
>> +	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 +654,8 @@ 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