[PATCH v10 0/2] scsi: ufs: Add support for static TX Equalization settings

[PATCH v10 0/2] scsi: ufs: Add support for static TX Equalization settings

[Can Guo]

Hi,

This series adds support for board-specific static TX Equalization settings
provided through Device Tree.

This series is based on the earlier TX Equalization enablement work and
persistent storage/retrieval of optimal TX Equalization settings work:
https://lore.kernel.org/all/20260325152154.1604082-1-can.guo@oss.qualcomm.com
https://lore.kernel.org/all/20260424151420.111675-1-can.guo@oss.qualcomm.com

Background
==========

UFS v5.0/UFSHCI v5.0 adds HS-G6 support (46.6 Gbps/lane) via UniPro v3.0
and M-PHY v6.0. These specs define TX Equalization for all High-Speed
Gears (not only HS-G6) to compensate channel loss and improve signal
integrity at high speed.

For HS-G6, M-PHY uses PAM4 1b1b line coding. Pre-Coding may also be
required depending on channel characteristics.

This series adds vendor-neutral DT properties:
- patternProperties: txeq-preshoot-g[1-6], txeq-deemphasis-g[1-6]
- fixed property: tx-precode-enable-g6

All properties use per-lane Host/Device tuples and accept 2 or 4 values
for x1/x2 lane configurations:
- txeq-preshoot-g[1-6]: values 0..7
- txeq-deemphasis-g[1-6]: values 0..7
- tx-precode-enable-g6: values 0/1

These properties carry board-level SI characterization data used as static
TX Equalization settings for each High-Speed Gear.

Example DTS snippet
===================

The following x2-lane example shows the expected DT encoding:

	ufs@1d84000 {
		lanes-per-direction = <2>;

		txeq-preshoot-g6 = <1 2>, <3 4>;
		txeq-deemphasis-g6 = <0 1>, <2 3>;
		tx-precode-enable-g6 = <1 0>, <0 1>;
	};

Relationship with Adaptive TX Equalization
==========================================

Adaptive TX Equalization remains the primary path when enabled.

Static TX Equalization settings from DT are board-specific baseline values,
but when adaptive TX Equalization is used, 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.

No behavior changes for platforms that do not provide these properties.

What this series adds
=====================

1. dt-bindings:
- Document txeq-preshoot-g[1-6], txeq-deemphasis-g[1-6], and
  tx-precode-enable-g6 in ufs-common.yaml.
- Define tuple encoding for host/device values per lane.
- Add per-property value validation ranges in schema.

2. UFS core/platform integration:
- Parse and validate per-gear DT TX EQ settings during platform init.
- Store parsed values into per-gear TX EQ params and track DT origin using
  the from_dt flag.
- Integrate static-state handling in TX EQ flow so DT-provided entries are
  fed through the adaptive TX Equalization path and then converted to
  normal runtime params.

v9 -> v10:
- Incorporated review comments from Bart (patch 1).
- Included Reviewed-by tag from Krzysztof Kozlowski (patch 1)
- Included Reviewed-by tag from Manivannan Sadhasivam (patch 1 & 2)
- Included Reviewed-by tag from Peter Wang (patch 1 & 2)

v8 -> v9:
- Fix DT schema shape for TX EQ properties to use proper uint32-matrix tuple
  form (nested rows) for tx-precode-enable-g6, txeq-preshoot-g[1-6], and
  txeq-deemphasis-g[1-6].

v7 -> v8:
- Replace split HS-G6 precode lane-list properties
  (tx-precode-g6-host-lanes/tx-precode-g6-device-lanes) with a single
  tx-precode-enable-g6 tuple property in the binding.
- Update parser in patch 2 to read tx-precode-enable-g6 as Host/Device
  tuples and validate full lane coverage and 0/1 values.
- Rename is_static to from_dt for clearer semantics in TX EQ params.
- Update commit messages for clarity and consistency.

v6 -> v7:
- Add DTS properties example in the cover letter.
- Replace tx-precode-enable-g6 tuple encoding with split lane-list
  properties:
  tx-precode-g6-host-lanes and tx-precode-g6-device-lanes.
- Update parser in patch 2 to read optional u32 lane-index arrays and
  treat unlisted lanes as precode disabled.
- Refactor patch 2 TX EQ property parsing to share a single helper for
  txeq-preshoot-gN/txeq-deemphasis-gN array read and validation.
- Dropped Reviewed-by/Acked-by due to code changes.

v5 -> v6:
- Use num_elems instead of count in the per-property validation loops for
  clarity (patch 2).
- Change else if (lpd > UFS_MAX_LANES) to a plain if after the !lpd early
  return, per kernel style (patch 2).

v4 -> v5:
- Extract the body of the per-gear for-loop in
  ufshcd_parse_static_tx_eq_settings() into a new helper
  ufshcd_parse_tx_eq_settings_for_gear() to reduce indentation depth
  (patch 2).
- Mark lpd and num_elems as const u32; rename sz to num_elems for clarity;
  use %u format specifier to match (patch 2).
- Replace size_t with u32 for the element-count variable (patch 2).
- Emit dev_warn() when lanes_per_direction exceeds UFS_MAX_LANES
  (patch 2).

v3 -> v4:
- Add Acked-by from Manivannan Sadhasivam to patch 1.
- Remove spurious dev_err() on the lpd guard in patch 2 (lpd == 0 is
  normal on platforms without lanes-per-direction in DT, not an error).
- Improve comment above the is_static condition in patch 2 to read
  "valid but static, i.e., populated from DT" for clarity.

v2 -> v3:
- Split the DT TX EQ binding into semantically separate properties:
  txeq-preshoot-g*, txeq-deemphasis-g*, tx-precode-g6-*-lanes.
- Place precode properties in properties (fixed keys) instead of
  patternProperties to satisfy dt-schema meta-schema rules.
- Restrict precode property to HS-G6 and document per-property ranges.
- Update the core parser to consume split properties.
- Drop unrelated arch/arm64/configs/defconfig changes from patch 2.

v1 -> v2:
- Improve the commit message of patch 1.


Can Guo (2):
  dt-bindings: ufs: Document static TX Equalization settings properties
  scsi: ufs: core: Add support for static TX Equalization settings

 .../devicetree/bindings/ufs/ufs-common.yaml   |  58 +++++++
 drivers/ufs/core/ufs-txeq.c                   |  15 +-
 drivers/ufs/host/ufshcd-pltfrm.c              | 155 ++++++++++++++++++
 include/ufs/ufshcd.h                          |   2 +
 4 files changed, 229 insertions(+), 1 deletion(-)

-- 
2.34.1

[PATCH v10 1/2] dt-bindings: ufs: Document static TX Equalization settings properties

[Can Guo]

UFS v5.0/UFSHCI v5.0 adds HS-G6 support (46.6 Gbps/lane) via UniPro
v3.0 and M-PHY v6.0. These specs define TX Equalization for all
High-Speed Gears (not only HS-G6) to compensate channel loss and
improve signal integrity at high speed.

For HS-G6, M-PHY uses PAM4 1b1b line coding. Pre-Coding may also be
required depending on channel characteristics.

Document vendor-neutral properties in ufs-common.yaml:
- txeq-preshoot-g[1-6]
- txeq-deemphasis-g[1-6]
- tx-precode-enable-g6

Values are per-lane Host/Device tuples (2 values for x1, 4 values for
x2). PreShoot/DeEmphasis range from 0..7, and Precode is 0/1.

These are board-specific signal-integrity tuning values. They depend on
channel SI/PHY characterization and validation (host PHY, device PHY,
package, and board routing), and are determined by HW/PHY designers.

Although UFSHCI v5.0 supports TX Equalization Training via UniPro v3.0,
which allows host software to determine optimal TX Equalization at
runtime, static board-specific TX Equalization settings in the Device
Tree are still necessary because:
- TX Equalization Training is not supported for HS-G3 and below
- TX Equalization Training is disabled on some platforms

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>
Reviewed-by: Peter Wang <peter.wang@mediatek.com>
Signed-off-by: Can Guo <can.guo@oss.qualcomm.com>
---
 .../devicetree/bindings/ufs/ufs-common.yaml   | 58 +++++++++++++++++++
 1 file changed, 58 insertions(+)

diff --git a/Documentation/devicetree/bindings/ufs/ufs-common.yaml b/Documentation/devicetree/bindings/ufs/ufs-common.yaml
index ed97f5682509..cc32e1189d50 100644
--- a/Documentation/devicetree/bindings/ufs/ufs-common.yaml
+++ b/Documentation/devicetree/bindings/ufs/ufs-common.yaml
@@ -105,6 +105,64 @@ properties:
       Restricts the UFS controller to rate-a or rate-b for both TX and
       RX directions.
 
+  tx-precode-enable-g6:
+    $ref: /schemas/types.yaml#/definitions/uint32-matrix
+    minItems: 1
+    items:
+      - items:
+          - description: Host_Lane0 precode
+            enum: [0, 1]
+          - description: Device_Lane0 precode
+            enum: [0, 1]
+      - items:
+          - description: Host_Lane1 precode
+            enum: [0, 1]
+          - description: Device_Lane1 precode
+            enum: [0, 1]
+    description:
+      Static TX Precode enable values for HS-G6 only.
+
+patternProperties:
+  "^txeq-preshoot-g[1-6]$":
+    $ref: /schemas/types.yaml#/definitions/uint32-matrix
+    minItems: 1
+    items:
+      - items:
+          - description: Host_Lane0 Preshoot value
+            enum: [0, 1, 2, 3, 4, 5, 6, 7]
+          - description: Device_Lane0 Preshoot value
+            enum: [0, 1, 2, 3, 4, 5, 6, 7]
+      - items:
+          - description: Host_Lane1 Preshoot value
+            enum: [0, 1, 2, 3, 4, 5, 6, 7]
+          - description: Device_Lane1 Preshoot value
+            enum: [0, 1, 2, 3, 4, 5, 6, 7]
+    description: |
+      Static TX Equalization PreShoot settings for High Speed Gears. These
+      values are programmed to the corresponding UniPro PA layer attribute
+      PA_TxEQG[1-6]Setting. Each value selects a Pre-Shoot level as defined
+      by the MIPI M-PHY specification (TX_HS_PreShoot_Setting).
+
+  "^txeq-deemphasis-g[1-6]$":
+    $ref: /schemas/types.yaml#/definitions/uint32-matrix
+    minItems: 1
+    items:
+      - items:
+          - description: Host_Lane0 DeEmphasis value
+            enum: [0, 1, 2, 3, 4, 5, 6, 7]
+          - description: Device_Lane0 DeEmphasis value
+            enum: [0, 1, 2, 3, 4, 5, 6, 7]
+      - items:
+          - description: Host_Lane1 DeEmphasis value
+            enum: [0, 1, 2, 3, 4, 5, 6, 7]
+          - description: Device_Lane1 DeEmphasis value
+            enum: [0, 1, 2, 3, 4, 5, 6, 7]
+    description: |
+      Static TX Equalization DeEmphasis settings for High Speed Gears. These
+      values are programmed to the corresponding UniPro PA layer attribute
+      PA_TxEQG[1-6]Setting. Each value selects a De-Emphasis level as defined
+      by the MIPI M-PHY specification (TX_HS_DeEmphasis_Setting).
+
 dependencies:
   freq-table-hz: [ clocks ]
   operating-points-v2: [ clocks, clock-names ]
-- 
2.34.1

[PATCH v10 2/2] scsi: ufs: core: Add support for static TX Equalization settings

[Can Guo]

Parse board-specific static TX Equalization settings from Device Tree for
each HS gear and store them in hba->tx_eq_params.

Parse txeq-preshoot-g[1-6] and txeq-deemphasis-g[1-6] as per-lane tuples:
<Host_Lane0 Device_Lane0>, [<Host_Lane1 Device_Lane1>].

For HS-G6, parse optional tx-precode-enable-g6 using the same per-lane
Host/Device tuple format. If provided, it must contain values for all
active lanes, and each value must be 0 or 1.

Introduce from_dt in struct ufshcd_tx_eq_params to track whether TX EQ
values came from static Device Tree data.

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 Device Tree settings.
- If retrieval is not available/valid, TX EQTR runs and trained settings
  override static Device Tree settings.

So static Device Tree settings are a fallback for cases where adaptive TX
Equalization is not enabled or not used. Adaptive TX Equalization remains
the primary path when enabled.

No behavior changes for platforms that do not provide these properties.

Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>
Reviewed-by: Peter Wang <peter.wang@mediatek.com>
Signed-off-by: Can Guo <can.guo@oss.qualcomm.com>
---
 drivers/ufs/core/ufs-txeq.c      |  15 ++-
 drivers/ufs/host/ufshcd-pltfrm.c | 154 +++++++++++++++++++++++++++++++
 include/ufs/ufshcd.h             |   2 +
 3 files changed, 170 insertions(+), 1 deletion(-)

diff --git a/drivers/ufs/core/ufs-txeq.c b/drivers/ufs/core/ufs-txeq.c
index 3a2fb5329d27..3c94b94dd7b7 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 from Device Tree.
+	 * 3. TX EQTR procedure is forced.
+	 */
+	if (!params->is_valid || params->from_dt || force_tx_eqtr) {
 		int ret;
 
 		ret = ufshcd_tx_eqtr(hba, params, pwr_mode);
@@ -1310,6 +1316,8 @@ int ufshcd_config_tx_eq_settings(struct ufs_hba *hba,
 		/* Mark TX Equalization settings as valid */
 		params->is_valid = true;
 		params->is_trained = true;
+		/* TX EQTR succeeds, clear from_dt flag */
+		params->from_dt = false;
 		params->is_applied = false;
 	}
 
@@ -1495,6 +1503,11 @@ static void ufshcd_extract_tx_eq_settings_attrs(struct ufs_hba *hba, u8 gear)
 	}
 
 	params->is_valid = true;
+	/*
+	 * Optimal TX EQ settings are retrieved from UFS device attributes,
+	 * clear from_dt flag to avoid TX EQTR procedure.
+	 */
+	params->from_dt = 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..5ac7afe75934 100644
--- a/drivers/ufs/host/ufshcd-pltfrm.c
+++ b/drivers/ufs/host/ufshcd-pltfrm.c
@@ -210,6 +210,158 @@ static void ufshcd_init_lanes_per_dir(struct ufs_hba *hba)
 	}
 }
 
+static int ufshcd_parse_tx_precode_enable(struct ufs_hba *hba,
+					  bool host_precode_en[UFS_MAX_LANES],
+					  bool device_precode_en[UFS_MAX_LANES])
+{
+	const char *prop_name = "tx-precode-enable-g6";
+	u32 num_elems = 2 * hba->lanes_per_direction;
+	const u32 lpd = hba->lanes_per_direction;
+	u32 precode[UFS_MAX_LANES * 2];
+	struct device *dev = hba->dev;
+	int count, err, i;
+
+	count = of_property_count_u32_elems(dev->of_node, prop_name);
+	if (count == -EINVAL || count == -ENODATA)
+		return 0;
+
+	if (count < 0)
+		return count;
+
+	if (count != num_elems) {
+		dev_err(dev, "Property %s has invalid count (%d), expecting %u\n",
+			prop_name, count, num_elems);
+		return -EINVAL;
+	}
+
+	err = of_property_read_u32_array(dev->of_node, prop_name, precode, num_elems);
+	if (err) {
+		dev_err(dev, "Failed to read %s property, %d\n", prop_name, err);
+		return err;
+	}
+
+	for (i = 0; i < num_elems; i++) {
+		if (precode[i] > 1) {
+			dev_err(dev, "Invalid TX precode value (%u) in %s property\n",
+				precode[i], prop_name);
+			return -EINVAL;
+		}
+	}
+
+	for (i = 0; i < lpd; i++) {
+		host_precode_en[i] = precode[i * 2];
+		device_precode_en[i] = precode[i * 2 + 1];
+	}
+
+	return 0;
+}
+
+static int ufshcd_parse_tx_eq_value_array(struct ufs_hba *hba,
+					  const char *prop_name,
+					  const u32 max_value,
+					  u32 values[UFS_MAX_LANES * 2])
+{
+	u32 num_elems = 2 * hba->lanes_per_direction;
+	struct device *dev = hba->dev;
+	int count, err, i;
+
+	count = of_property_count_u32_elems(dev->of_node, prop_name);
+	if (count < 0)
+		return count;
+
+	if (count != num_elems) {
+		dev_err(dev, "Property %s has invalid count (%d), expecting %u\n",
+			prop_name, count, num_elems);
+		return -EINVAL;
+	}
+
+	err = of_property_read_u32_array(dev->of_node, prop_name, values, num_elems);
+	if (err) {
+		dev_err(dev, "Failed to read %s property, %d\n", prop_name, err);
+		return err;
+	}
+
+	for (i = 0; i < num_elems; i++) {
+		if (values[i] >= max_value) {
+			dev_err(dev, "Invalid TX EQ value (%u) in %s property\n",
+				values[i], prop_name);
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * ufshcd_parse_tx_eq_settings_for_gear - Parse static TX EQ DT settings for one gear
+ * @hba: per adapter instance
+ * @gear: target HS gear
+ *
+ * Reads the txeq-preshoot-gN, txeq-deemphasis-gN, and (for G6)
+ * tx-precode-enable-g6 device-tree properties.
+ * If all present values are valid, stores them as static TX Equalization
+ * settings for the given gear.
+ */
+static void ufshcd_parse_tx_eq_settings_for_gear(struct ufs_hba *hba, int gear)
+{
+	bool device_precode_en[UFS_MAX_LANES] = { false };
+	bool host_precode_en[UFS_MAX_LANES] = { false };
+	const u32 lpd = hba->lanes_per_direction;
+	struct ufshcd_tx_eq_params *params;
+	u32 deemphasis[UFS_MAX_LANES * 2];
+	u32 preshoot[UFS_MAX_LANES * 2];
+	char prop_name[MAX_PROP_SIZE];
+	int err, lane;
+
+	snprintf(prop_name, MAX_PROP_SIZE, "txeq-preshoot-g%d", gear);
+	err = ufshcd_parse_tx_eq_value_array(hba, prop_name, TX_HS_NUM_PRESHOOT, preshoot);
+	if (err)
+		return;
+
+	snprintf(prop_name, MAX_PROP_SIZE, "txeq-deemphasis-g%d", gear);
+	err = ufshcd_parse_tx_eq_value_array(hba, prop_name, TX_HS_NUM_DEEMPHASIS, deemphasis);
+	if (err)
+		return;
+
+	if (gear == UFS_HS_G6) {
+		err = ufshcd_parse_tx_precode_enable(hba, host_precode_en, device_precode_en);
+		if (err)
+			return;
+	}
+
+	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 = host_precode_en[lane];
+
+		params->device[lane].preshoot = preshoot[lane * 2 + 1];
+		params->device[lane].deemphasis = deemphasis[lane * 2 + 1];
+		params->device[lane].precode_en = device_precode_en[lane];
+	}
+
+	params->is_valid = true;
+	params->from_dt = true;
+}
+
+static void ufshcd_parse_static_tx_eq_settings(struct ufs_hba *hba)
+{
+	const u32 lpd = hba->lanes_per_direction;
+	int gear;
+
+	if (!lpd)
+		return;
+
+	if (lpd > UFS_MAX_LANES) {
+		dev_warn(hba->dev, "lanes_per_direction (%u) exceeds UFS_MAX_LANES (%u)\n",
+			 lpd, UFS_MAX_LANES);
+		return;
+	}
+
+	for (gear = UFS_HS_G1; gear <= UFS_HS_GEAR_MAX; gear++)
+		ufshcd_parse_tx_eq_settings_for_gear(hba, gear);
+}
+
 /**
  * ufshcd_parse_clock_min_max_freq  - Parse MIN and MAX clocks freq
  * @hba: per adapter instance
@@ -528,6 +680,8 @@ 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..0f87b081b2ff 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
+ * @from_dt: True if settings are from Device Tree
  */
 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 from_dt;
 };
 
 /**
-- 
2.34.1

Re: [PATCH v10 2/2] scsi: ufs: core: Add support for static TX Equalization settings

[Bart Van Assche]

On 6/16/26 4:33 AM, Can Guo wrote:
> Parse board-specific static TX Equalization settings from Device Tree for
> each HS gear and store them in hba->tx_eq_params.
> 
> Parse txeq-preshoot-g[1-6] and txeq-deemphasis-g[1-6] as per-lane tuples:
> <Host_Lane0 Device_Lane0>, [<Host_Lane1 Device_Lane1>].
> 
> For HS-G6, parse optional tx-precode-enable-g6 using the same per-lane
> Host/Device tuple format. If provided, it must contain values for all
> active lanes, and each value must be 0 or 1.
> 
> Introduce from_dt in struct ufshcd_tx_eq_params to track whether TX EQ
> values came from static Device Tree data.
> 
> 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 Device Tree settings.
> - If retrieval is not available/valid, TX EQTR runs and trained settings
>    override static Device Tree settings.
> 
> So static Device Tree settings are a fallback for cases where adaptive TX
> Equalization is not enabled or not used. Adaptive TX Equalization remains
> the primary path when enabled.
> 
> No behavior changes for platforms that do not provide these properties.

Reviewed-by: Bart Van Assche <bvanassche@acm.org>

In the future, please wait at least 24 hours before posting a new
version of a patch series. For this patch series it has happened that a
new version was posted before I had the chance to comment on a previous
version.

Thanks,

Bart.

Re: [PATCH v10 0/2] scsi: ufs: Add support for static TX Equalization settings

[Martin K. Petersen]

Can,

> This series adds support for board-specific static TX Equalization
> settings provided through Device Tree.

Applied to 7.3/scsi-staging, thanks!

-- 
Martin K. Petersen