linux-kernel - [PATCH AUTOSEL 6.5 10/41] scsi: ufs: core: Poll HCS.UCRDY before issuing a UIC command

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Message-Id: <20230924131529.1275335-10-sashal@kernel.org>
Date:   Sun, 24 Sep 2023 09:14:58 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Kiwoong Kim <kwmad.kim@...sung.com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Chanwoo Lee <cw9316.lee@...sung.com>,
        "Martin K . Petersen" <martin.petersen@...cle.com>,
        Sasha Levin <sashal@...nel.org>, jejb@...ux.ibm.com,
        bvanassche@....org, stanley.chu@...iatek.com,
        quic_cang@...cinc.com, mani@...nel.org, quic_asutoshd@...cinc.com,
        beanhuo@...ron.com, quic_nguyenb@...cinc.com,
        Arthur.Simchaev@....com, linux-scsi@...r.kernel.org
Subject: [PATCH AUTOSEL 6.5 10/41] scsi: ufs: core: Poll HCS.UCRDY before issuing a UIC command

From: Kiwoong Kim <kwmad.kim@...sung.com>

[ Upstream commit d32533d30e2119b0c0aa17596734f1f842f750df ]

With auto hibern8 enabled, UIC could be busy processing a hibern8 operation
and the HCI would reports UIC not ready for a short while through
HCS.UCRDY. The UFS driver doesn't currently handle this situation. The
UFSHCI spec specifies UCRDY like this: whether the host controller is ready
to process UIC COMMAND

The 'ready' could be seen as many different meanings. If the meaning
includes not processing any request from HCI, processing a hibern8
operation can be 'not ready'. In this situation, the driver needs to wait
until the operations is completed.

Signed-off-by: Kiwoong Kim <kwmad.kim@...sung.com>
Link: https://lore.kernel.org/r/550484ffb66300bdcec63d3e304dfd55cb432f1f.1693790060.git.kwmad.kim@samsung.com
Reviewed-by: Adrian Hunter <adrian.hunter@...el.com>
Reviewed-by: Chanwoo Lee <cw9316.lee@...sung.com>
Signed-off-by: Martin K. Petersen <martin.petersen@...cle.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/ufs/core/ufshcd.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index 75c6628af2c0e..80c48eb6bf85c 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -22,6 +22,7 @@
 #include <linux/module.h>
 #include <linux/regulator/consumer.h>
 #include <linux/sched/clock.h>
+#include <linux/iopoll.h>
 #include <scsi/scsi_cmnd.h>
 #include <scsi/scsi_dbg.h>
 #include <scsi/scsi_driver.h>
@@ -2324,7 +2325,11 @@ static inline int ufshcd_hba_capabilities(struct ufs_hba *hba)
  */
 static inline bool ufshcd_ready_for_uic_cmd(struct ufs_hba *hba)
 {
-	return ufshcd_readl(hba, REG_CONTROLLER_STATUS) & UIC_COMMAND_READY;
+	u32 val;
+	int ret = read_poll_timeout(ufshcd_readl, val, val & UIC_COMMAND_READY,
+				    500, UIC_CMD_TIMEOUT * 1000, false, hba,
+				    REG_CONTROLLER_STATUS);
+	return ret == 0 ? true : false;
 }
 
 /**
-- 
2.40.1