linux-kernel - [PATCH] scsi: ufs: Try to save power mode change and UIC cmd completion timeout

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Date:   Mon,  2 Nov 2020 22:24:41 -0800
From:   Can Guo <cang@...eaurora.org>
To:     asutoshd@...eaurora.org, nguyenb@...eaurora.org,
        hongwus@...eaurora.org, rnayak@...eaurora.org,
        linux-scsi@...r.kernel.org, kernel-team@...roid.com,
        saravanak@...gle.com, salyzyn@...gle.com, cang@...eaurora.org
Cc:     Alim Akhtar <alim.akhtar@...sung.com>,
        Avri Altman <avri.altman@....com>,
        "James E.J. Bottomley" <jejb@...ux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@...cle.com>,
        Stanley Chu <stanley.chu@...iatek.com>,
        Bean Huo <beanhuo@...ron.com>,
        Bart Van Assche <bvanassche@....org>,
        linux-kernel@...r.kernel.org (open list)
Subject: [PATCH] scsi: ufs: Try to save power mode change and UIC cmd completion timeout

Use the uic_cmd->cmd_active as a flag to track the lifecycle of an UIC cmd.
The flag is set before send the UIC cmd and cleared after the completion is
raised in IRQ handler. For a power mode change operation, including hibern8
enter/exit, the flag is cleared only after hba->uic_async_done completion
is raised. When completion timeout happens, if the flag is cleared, instead
of returning timeout error, simply ignore it.

Change-Id: Ie3cd6ae6221a44619925fb2cf78136a5617fdd5d
Signed-off-by: Can Guo <cang@...eaurora.org>
---
 drivers/scsi/ufs/ufshcd.c | 26 ++++++++++++++++++++++++--
 1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 252e022..8b291c3 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -2131,10 +2131,20 @@ ufshcd_wait_for_uic_cmd(struct ufs_hba *hba, struct uic_command *uic_cmd)
 	unsigned long flags;
 
 	if (wait_for_completion_timeout(&uic_cmd->done,
-					msecs_to_jiffies(UIC_CMD_TIMEOUT)))
+					msecs_to_jiffies(UIC_CMD_TIMEOUT))) {
 		ret = uic_cmd->argument2 & MASK_UIC_COMMAND_RESULT;
-	else
+	} else {
 		ret = -ETIMEDOUT;
+		dev_err(hba->dev,
+			"uic cmd 0x%x with arg3 0x%x completion timeout\n",
+			uic_cmd->command, uic_cmd->argument3);
+
+		if (!uic_cmd->cmd_active) {
+			dev_err(hba->dev, "%s: UIC cmd has been completed, return the result\n",
+				__func__);
+			ret = uic_cmd->argument2 & MASK_UIC_COMMAND_RESULT;
+		}
+	}
 
 	spin_lock_irqsave(hba->host->host_lock, flags);
 	hba->active_uic_cmd = NULL;
@@ -2166,6 +2176,7 @@ __ufshcd_send_uic_cmd(struct ufs_hba *hba, struct uic_command *uic_cmd,
 	if (completion)
 		init_completion(&uic_cmd->done);
 
+	uic_cmd->cmd_active = 1;
 	ufshcd_dispatch_uic_cmd(hba, uic_cmd);
 
 	return 0;
@@ -3944,10 +3955,18 @@ static int ufshcd_uic_pwr_ctrl(struct ufs_hba *hba, struct uic_command *cmd)
 		dev_err(hba->dev,
 			"pwr ctrl cmd 0x%x with mode 0x%x completion timeout\n",
 			cmd->command, cmd->argument3);
+
+		if (!cmd->cmd_active) {
+			dev_err(hba->dev, "%s: Power Mode Change operation has been completed, go check UPMCRS\n",
+				__func__);
+			goto check_upmcrs;
+		}
+
 		ret = -ETIMEDOUT;
 		goto out;
 	}
 
+check_upmcrs:
 	status = ufshcd_get_upmcrs(hba);
 	if (status != PWR_LOCAL) {
 		dev_err(hba->dev,
@@ -5060,11 +5079,14 @@ static irqreturn_t ufshcd_uic_cmd_compl(struct ufs_hba *hba, u32 intr_status)
 		hba->active_uic_cmd->argument3 =
 			ufshcd_get_dme_attr_val(hba);
 		complete(&hba->active_uic_cmd->done);
+		if (!hba->uic_async_done)
+			hba->active_uic_cmd->cmd_active = 0;
 		retval = IRQ_HANDLED;
 	}
 
 	if ((intr_status & UFSHCD_UIC_PWR_MASK) && hba->uic_async_done) {
 		complete(hba->uic_async_done);
+		hba->active_uic_cmd->cmd_active = 0;
 		retval = IRQ_HANDLED;
 	}
 	return retval;
-- 
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