[PATCH v4 22/23] scsi: ufs: ufs-qcom: Add support for finding max gear on new platforms

[Manivannan Sadhasivam]

Starting from Qcom UFS version 4.0, vendor specific REG_UFS_PARAM0 register
can be used to determine the maximum gear supported by the controller.

Suggested-by: Can Guo <quic_cang at quicinc.com>
Reviewed-by: Andrew Halaney <ahalaney at redhat.com>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam at linaro.org>
---
 drivers/ufs/host/ufs-qcom.c | 2 ++
 drivers/ufs/host/ufs-qcom.h | 4 ++++
 2 files changed, 6 insertions(+)

diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
index 3efef2f36e69..607fddb7b4c3 100644
--- a/drivers/ufs/host/ufs-qcom.c
+++ b/drivers/ufs/host/ufs-qcom.c
@@ -291,6 +291,8 @@ static u32 ufs_qcom_get_hs_gear(struct ufs_hba *hba)
 		 * Hence downgrade the maximum supported gear to HS-G2.
 		 */
 		return UFS_HS_G2;
+	} else if (host->hw_ver.major >= 0x4) {
+		return UFS_QCOM_MAX_GEAR(ufshcd_readl(hba, REG_UFS_PARAM0));
 	}
 
 	/* Default is HS-G3 */
diff --git a/drivers/ufs/host/ufs-qcom.h b/drivers/ufs/host/ufs-qcom.h
index 4b00c67e9d7f..dd3abd23ec22 100644
--- a/drivers/ufs/host/ufs-qcom.h
+++ b/drivers/ufs/host/ufs-qcom.h
@@ -94,6 +94,10 @@ enum {
 #define TMRLUT_HW_CGC_EN	BIT(6)
 #define OCSC_HW_CGC_EN		BIT(7)
 
+/* bit definitions for REG_UFS_PARAM0 */
+#define MAX_HS_GEAR_MASK	GENMASK(6, 4)
+#define UFS_QCOM_MAX_GEAR(x)	FIELD_GET(MAX_HS_GEAR_MASK, (x))
+
 /* bit definition for UFS_UFS_TEST_BUS_CTRL_n */
 #define TEST_BUS_SUB_SEL_MASK	GENMASK(4, 0)  /* All XXX_SEL fields are 5 bits wide */
 
-- 
2.25.1