[PATCH v2 01/10] scsi: ufs: Allowing power mode change

[Asutosh Das]

From: Yaniv Gardi <ygardi@xxxxxxxxxxxxxx>

Due to M-PHY issues, moving from HS to any other mode or gear or
even Hibern8 may cause some un-predicted behavior
of the device.
This patch adds provides a quirk to address that.

Signed-off-by: Yaniv Gardi <ygardi@xxxxxxxxxxxxxx>
Signed-off-by: Subhash Jadavani <subhashj@xxxxxxxxxxxxxx>
Signed-off-by: Can Guo <cang@xxxxxxxxxxxxxx>
Signed-off-by: Asutosh Das <asutoshd@xxxxxxxxxxxxxx>
---
 drivers/scsi/ufs/ufshcd.c | 8 +++++++-
 drivers/scsi/ufs/ufshcd.h | 7 +++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 5bc9dc1..f3083fe 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -4162,9 +4162,15 @@ static int ufshcd_link_startup(struct ufs_hba *hba)
 			goto out;
 	} while (ret && retries--);
 
-	if (ret)
+	if (ret) {
 		/* failed to get the link up... retire */
 		goto out;
+	}
+
+	if (hba->quirks & UFSHCD_QUIRK_BROKEN_PWR_MODE_CHANGE) {
+		ufshcd_dme_set(hba, UIC_ARG_MIB(TX_LCC_ENABLE), 0);
+		ufshcd_dme_set(hba, UIC_ARG_MIB(TX_LCC_ENABLE), 1);
+	}
 
 	if (link_startup_again) {
 		link_startup_again = false;
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index cbe46f6..bb4ecfb 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -591,6 +591,13 @@ struct ufs_hba {
 	 */
 	#define UFSHCD_QUIRK_PRDT_BYTE_GRAN			UFS_BIT(7)
 
+	/*
+	 * Needs to be enabled if moving from HS to any other gear/mode or even
+	 * hibern8 causes unpredicted behavior of device.
+	 * If this quirk is enabled, standard UFS driver will disable/enable
+	 * TX_LCC.
+	 */
+	#define UFSHCD_QUIRK_BROKEN_PWR_MODE_CHANGE		UFS_BIT(8)
 	unsigned int quirks;	/* Deviations from standard UFSHCI spec. */
 
 	/* Device deviations from standard UFS device spec. */
-- 
Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc. 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.