[PATCH 2/6] scsi: ufs: ufs-qcom: Add support for UFS device version detection

[Can Guo]

From: "Bao D. Nguyen" <quic_nguyenb@xxxxxxxxxxx>

Retrieve UFS device version from UFS host controller's spare register
which is populated by bootloader, and use the UFS device version together
with host controller's HW version to decide the proper power modes which
should be used to configure the UFS PHY.

Signed-off-by: Bao D. Nguyen <quic_nguyenb@xxxxxxxxxxx>
Signed-off-by: Can Guo <quic_cang@xxxxxxxxxxx>
---
 drivers/ufs/host/ufs-qcom.c | 30 +++++++++++++++++++++++-------
 drivers/ufs/host/ufs-qcom.h |  2 ++
 2 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
index 710f079..8a9d54f 100644
--- a/drivers/ufs/host/ufs-qcom.c
+++ b/drivers/ufs/host/ufs-qcom.c
@@ -1030,7 +1030,7 @@ static void ufs_qcom_advertise_quirks(struct ufs_hba *hba)
 				| UFSHCD_QUIRK_BROKEN_PA_RXHSUNTERMCAP);
 	}
 
-	if (host->hw_ver.major > 0x3)
+	if (host->hw_ver.major > 0x3 && host->hw_ver.major < 0x5)
 		hba->quirks |= UFSHCD_QUIRK_REINIT_AFTER_MAX_GEAR_SWITCH;
 }
 
@@ -1038,11 +1038,33 @@ static void ufs_qcom_set_pwr_mode_limits(struct ufs_hba *hba)
 {
 	struct ufs_qcom_host *host = ufshcd_get_variant(hba);
 	struct ufs_dev_params *host_pwr_cap = &host->host_pwr_cap;
+	u32 val, dev_major = 0;
 
 	ufshcd_init_pwr_dev_param(host_pwr_cap);
 
 	/* This driver only supports symmetic gear setting i.e., hs_tx_gear == hs_rx_gear */
 	host_pwr_cap->hs_tx_gear = host_pwr_cap->hs_rx_gear = ufs_qcom_get_hs_gear(hba);
+	host->phy_gear = host_pwr_cap->hs_rx_gear;
+
+	if (host->hw_ver.major < 0x5) {
+		/*
+		 * Power up the PHY using the minimum supported gear (UFS_HS_G2).
+		 * Switching to max gear will be performed during reinit if supported.
+		 */
+		host->phy_gear = UFS_HS_G2;
+	} else {
+		val = ufshcd_readl(host->hba, REG_UFS_DEBUG_SPARE_CFG);
+		dev_major = FIELD_GET(GENMASK(7, 4), val);
+
+		if (host->hw_ver.major == 0x5 && (dev_major >= 0x4 ||
+						  dev_major == 0)) {
+			/* For UFS 4.0 and newer, or dev version is not populated */
+			host_pwr_cap->hs_rate = PA_HS_MODE_A;
+		} else if (dev_major < 0x4 && dev_major > 0) {
+			/* For UFS 3.1 and older, apply HS-G4 PHY settings to save power */
+			host->phy_gear = UFS_HS_G4;
+		}
+	}
 }
 
 static void ufs_qcom_set_caps(struct ufs_hba *hba)
@@ -1287,12 +1309,6 @@ static int ufs_qcom_init(struct ufs_hba *hba)
 		dev_warn(dev, "%s: failed to configure the testbus %d\n",
 				__func__, err);
 
-	/*
-	 * Power up the PHY using the minimum supported gear (UFS_HS_G2).
-	 * Switching to max gear will be performed during reinit if supported.
-	 */
-	host->phy_gear = UFS_HS_G2;
-
 	return 0;
 
 out_variant_clear:
diff --git a/drivers/ufs/host/ufs-qcom.h b/drivers/ufs/host/ufs-qcom.h
index 4db64d9..e10889f 100644
--- a/drivers/ufs/host/ufs-qcom.h
+++ b/drivers/ufs/host/ufs-qcom.h
@@ -56,6 +56,8 @@ enum {
 	UFS_AH8_CFG				= 0xFC,
 
 	REG_UFS_CFG3				= 0x271C,
+
+	REG_UFS_DEBUG_SPARE_CFG			= 0x284C,
 };
 
 /* QCOM UFS host controller vendor specific debug registers */
-- 
2.7.4