Merge patch series "scsi: ufs: Harden TX EQTR error handling paths"

Can Guo <can.guo@oss.qualcomm.com> says:

TX Equalization training currently has a few error-path gaps that can
make the flow brittle and can leave variant/device cleanup incomplete.

This series hardens TX EQTR in three places:

 1. ufs-qcom: route SW FOM setup failures through the shared cleanup
    path so temporary device TX EQ settings are restored and link
    recovery is always attempted before exit.

 2. core: treat RX_FOM DME read failures as best effort so TX EQTR can
    continue, and force failed lanes to deterministic 0 FOM.

 3. core: always run tx_eqtr POST_CHANGE notify once PRE_CHANGE
    succeeds, even when TX EQTR fails, so variant cleanup is not
    skipped.

Together these changes improve TX EQTR robustness without changing the
normal success path.

Link: https://patch.msgid.link/20260625121306.1655467-1-can.guo@oss.qualcomm.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

2 files changed, 28 insertions, 14 deletions

diff --git a/drivers/ufs/core/ufs-txeq.c b/drivers/ufs/core/ufs-txeq.c
index a083094a0465..fa5f539632eb 100644
--- a/drivers/ufs/core/ufs-txeq.c
+++ b/drivers/ufs/core/ufs-txeq.c
@@ -482,7 +482,8 @@ static void ufshcd_evaluate_tx_eqtr_fom(struct ufs_hba *hba,
  * @h_iter: host TX EQTR iterator data structure
  * @d_iter: device TX EQTR iterator data structure
  *
- * Returns 0 on success, negative error code otherwise
+ * Returns 0 on success, negative error code if get_rx_fom vops fails.
+ * RX_FOM DME get failures are logged and treated as 0 FOM for that lane.
  */
 static int ufshcd_get_rx_fom(struct ufs_hba *hba,
 			     struct ufs_pa_layer_attr *pwr_mode,
@@ -497,8 +498,12 @@ static int ufshcd_get_rx_fom(struct ufs_hba *hba,
 		ret = ufshcd_dme_peer_get(hba, UIC_ARG_MIB_SEL(RX_FOM,
 					  UIC_ARG_MPHY_RX_GEN_SEL_INDEX(lane)),
 					  &fom);
-		if (ret)
-			return ret;
+		if (ret) {
+			h_iter->fom[lane] = 0;
+			dev_dbg(hba->dev, "Failed to get FOM for Host TX Lane %d: %d\n",
+				 lane, ret);
+			continue;
+		}
 
 		h_iter->fom[lane] = (u8)fom;
 	}
@@ -508,8 +513,12 @@ static int ufshcd_get_rx_fom(struct ufs_hba *hba,
 		ret = ufshcd_dme_get(hba, UIC_ARG_MIB_SEL(RX_FOM,
 				     UIC_ARG_MPHY_RX_GEN_SEL_INDEX(lane)),
 				     &fom);
-		if (ret)
-			return ret;
+		if (ret) {
+			d_iter->fom[lane] = 0;
+			dev_dbg(hba->dev, "Failed to get FOM for Device TX Lane %d: %d\n",
+				 lane, ret);
+			continue;
+		}
 
 		d_iter->fom[lane] = (u8)fom;
 	}
@@ -1218,6 +1227,7 @@ static int ufshcd_tx_eqtr(struct ufs_hba *hba,
 {
 	struct ufs_pa_layer_attr old_pwr_info;
 	unsigned int noio_flag;
+	int notify_ret;
 	int ret;
 
 	/*
@@ -1247,14 +1257,19 @@ static int ufshcd_tx_eqtr(struct ufs_hba *hba,
 	}
 
 	ret = ufshcd_vops_tx_eqtr_notify(hba, PRE_CHANGE, pwr_mode);
-	if (ret)
+	if (ret) {
+		dev_err(hba->dev, "TX EQTR PRE_CHANGE notify failed: %d\n", ret);
 		goto out_unprepare;
+	}
 
 	ret = __ufshcd_tx_eqtr(hba, params, pwr_mode);
-	if (ret)
-		goto out_unprepare;
 
-	ret = ufshcd_vops_tx_eqtr_notify(hba, POST_CHANGE, pwr_mode);
+	notify_ret = ufshcd_vops_tx_eqtr_notify(hba, POST_CHANGE, pwr_mode);
+	if (notify_ret)
+		dev_err(hba->dev, "TX EQTR POST_CHANGE notify failed: %d\n", notify_ret);
+
+	if (!ret)
+		ret = notify_ret;
 
 out_unprepare:
 	if (ret)
diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
index 291c43448764..0500320545c4 100644
--- a/drivers/ufs/host/ufs-qcom.c
+++ b/drivers/ufs/host/ufs-qcom.c
@@ -2794,7 +2794,7 @@ static int ufs_qcom_get_rx_fom(struct ufs_hba *hba,
 	if (ret) {
 		dev_err(hba->dev, "%s: Failed to apply TX EQ settings for HS-G%u: %d\n",
 			__func__, gear, ret);
-		return ret;
+		goto link_recover_and_restore;
 	}
 
 	/* Force PMC to target HS Gear to use new TX Equalization settings. */
@@ -2802,16 +2802,15 @@ static int ufs_qcom_get_rx_fom(struct ufs_hba *hba,
 	if (ret) {
 		dev_err(hba->dev, "%s: Failed to change power mode to HS-G%u, Rate-%s: %d\n",
 			__func__, gear, ufs_hs_rate_to_str(rate), ret);
-		return ret;
+		goto link_recover_and_restore;
 	}
 
 	ret = ufs_qcom_host_sw_rx_fom(hba, pwr_mode->lane_rx, fom);
-	if (ret) {
+	if (ret)
 		dev_err(hba->dev, "Failed to get SW FOM of TX (PreShoot: %u, DeEmphasis: %u): %d\n",
 			d_iter->preshoot, d_iter->deemphasis, ret);
-		return ret;
-	}
 
+link_recover_and_restore:
 	/* Restore Device's TX Equalization settings. */
 	ret = ufshcd_apply_tx_eq_settings(hba, &hba->tx_eq_params[gear - 1], gear);
 	if (ret) {