scsi: ufs: Change power mode on line reset

Line reset can occur during hibernate enter, exit or
during PA_INIT. In some cases, system slowness problem
is observed when line reset happened during hibernate
enter process in auto hibernate mode of operation as
link remains in PWM-G1 mode. To fix this problem, read
PA_PWRmode, PA_TxGear and PA_RxGear if line reset is
detected and if link is in PWM-G1 mode, initiate power
mode change to expected HS gear.

Change-Id: Ic06a11c917e8954743c4dcf80b89fedeec4584ed
Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
Signed-off-by: Sayali Lokhande <sayalil@codeaurora.org>

drivers/scsi/ufs/ufshcd.c

@@ -173,6 +173,9 @@ void ufshcd_update_query_stats(struct ufs_hba *hba,
 }
 #endif
 
+#define PWR_INFO_MASK	0xF
+#define PWR_RX_OFFSET	4
+
 #define UFSHCD_REQ_SENSE_SIZE	18
 
 #define UFSHCD_ENABLE_INTRS	(UTP_TRANSFER_REQ_COMPL |\
@@ -4653,8 +4656,9 @@ int ufshcd_change_power_mode(struct ufs_hba *hba,
 	int ret = 0;
 
 	/* if already configured to the requested pwr_mode */
-	if (pwr_mode->gear_rx == hba->pwr_info.gear_rx &&
-	    pwr_mode->gear_tx == hba->pwr_info.gear_tx &&
+	if (!hba->restore_needed &&
+		pwr_mode->gear_rx == hba->pwr_info.gear_rx &&
+		pwr_mode->gear_tx == hba->pwr_info.gear_tx &&
 	    pwr_mode->lane_rx == hba->pwr_info.lane_rx &&
 	    pwr_mode->lane_tx == hba->pwr_info.lane_tx &&
 	    pwr_mode->pwr_rx == hba->pwr_info.pwr_rx &&
@@ -6275,6 +6279,52 @@ static void ufshcd_update_uic_reg_hist(struct ufs_uic_err_reg_hist *reg_hist,
 	reg_hist->pos = (reg_hist->pos + 1) % UIC_ERR_REG_HIST_LENGTH;
 }
 
+static void ufshcd_rls_handler(struct work_struct *work)
+{
+	struct ufs_hba *hba;
+	int ret = 0;
+	u32 mode;
+
+	hba = container_of(work, struct ufs_hba, rls_work);
+	ufshcd_scsi_block_requests(hba);
+	pm_runtime_get_sync(hba->dev);
+	ret = ufshcd_wait_for_doorbell_clr(hba, U64_MAX);
+	if (ret) {
+		dev_err(hba->dev,
+			"Timed out (%d) waiting for DB to clear\n",
+			ret);
+		goto out;
+	}
+
+	ufshcd_dme_get(hba, UIC_ARG_MIB(PA_PWRMODE), &mode);
+	if (hba->pwr_info.pwr_rx != ((mode >> PWR_RX_OFFSET) & PWR_INFO_MASK))
+		hba->restore_needed = true;
+
+	if (hba->pwr_info.pwr_tx != (mode & PWR_INFO_MASK))
+		hba->restore_needed = true;
+
+	ufshcd_dme_get(hba, UIC_ARG_MIB(PA_RXGEAR), &mode);
+	if (hba->pwr_info.gear_rx != mode)
+		hba->restore_needed = true;
+
+	ufshcd_dme_get(hba, UIC_ARG_MIB(PA_TXGEAR), &mode);
+	if (hba->pwr_info.gear_tx != mode)
+		hba->restore_needed = true;
+
+	if (hba->restore_needed)
+		ret = ufshcd_config_pwr_mode(hba, &(hba->pwr_info));
+
+	if (ret)
+		dev_err(hba->dev, "%s: Failed setting power mode, err = %d\n",
+			__func__, ret);
+	else
+		hba->restore_needed = false;
+
+out:
+	ufshcd_scsi_unblock_requests(hba);
+	pm_runtime_put_sync(hba->dev);
+}
+
 /**
  * ufshcd_update_uic_error - check and set fatal UIC error flags.
  * @hba: per-adapter instance
@@ -6314,6 +6364,8 @@ static irqreturn_t ufshcd_update_uic_error(struct ufs_hba *hba)
 					hba->full_init_linereset = true;
 				}
 			}
+			if (!hba->full_init_linereset)
+				schedule_work(&hba->rls_work);
 		}
 		retval |= IRQ_HANDLED;
 	}
@@ -9922,6 +9974,7 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
 	/* Initialize work queues */
 	INIT_WORK(&hba->eh_work, ufshcd_err_handler);
 	INIT_WORK(&hba->eeh_work, ufshcd_exception_event_handler);
+	INIT_WORK(&hba->rls_work, ufshcd_rls_handler);
 
 	/* Initialize UIC command mutex */
 	mutex_init(&hba->uic_cmd_mutex);

drivers/scsi/ufs/ufshcd.h

@@ -854,6 +854,7 @@ struct ufs_hba {
 	/* Work Queues */
 	struct work_struct eh_work;
 	struct work_struct eeh_work;
+	struct work_struct rls_work;
 
 	/* HBA Errors */
 	u32 errors;
@@ -950,9 +951,10 @@ struct ufs_hba {
 
 	bool full_init_linereset;
 	struct pinctrl *pctrl;
-	
+
 	int			latency_hist_enabled;
 	struct io_latency_state io_lat_s;
+	bool restore_needed;
 };
 
 static inline void ufshcd_mark_shutdown_ongoing(struct ufs_hba *hba)