scsi: ufs: ufs-mediatek: ensure UniPro is not powered down before linkup

MediaTek Chipsets can enter proprietary UniPro low-power mode during
suspend while link is in hibern8 state. Make sure leaving low-power mode
before every link startup to prevent lockup in any possible error recovery
path.

At the same time, re-factor related funcitons to improve code readability.

Link: https://lore.kernel.org/r/20200129105251.12466-2-stanley.chu@mediatek.comReviewed-by: Alim Akhtar <alim.akhtar@samsung.com>
Reviewed-by: Bean Huo <beanhuo@micron.com>
Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/ufs/ufs-mediatek.c

@@ -30,6 +30,11 @@
 #define ufs_mtk_device_reset_ctrl(high, res) \
 	ufs_mtk_smc(UFS_MTK_SIP_DEVICE_RESET, high, res)
 
+#define ufs_mtk_unipro_powerdown(hba, powerdown) \
+	ufshcd_dme_set(hba, \
+		       UIC_ARG_MIB_SEL(VS_UNIPROPOWERDOWNCONTROL, 0), \
+		       powerdown)
+
 static void ufs_mtk_cfg_unipro_cg(struct ufs_hba *hba, bool enable)
 {
 	u32 tmp;
@@ -290,6 +295,8 @@ static int ufs_mtk_pre_link(struct ufs_hba *hba)
 	int ret;
 	u32 tmp;
 
+	ufs_mtk_unipro_powerdown(hba, 0);
+
 	/* disable deep stall */
 	ret = ufshcd_dme_get(hba, UIC_ARG_MIB(VS_SAVEPOWERCONTROL), &tmp);
 	if (ret)
@@ -390,9 +397,7 @@ static int ufs_mtk_link_set_hpm(struct ufs_hba *hba)
 	if (err)
 		return err;
 
-	err = ufshcd_dme_set(hba,
-			     UIC_ARG_MIB_SEL(VS_UNIPROPOWERDOWNCONTROL, 0),
-			     0);
+	err = ufs_mtk_unipro_powerdown(hba, 0);
 	if (err)
 		return err;
 
@@ -413,14 +418,10 @@ static int ufs_mtk_link_set_lpm(struct ufs_hba *hba)
 {
 	int err;
 
-	err = ufshcd_dme_set(hba,
-			     UIC_ARG_MIB_SEL(VS_UNIPROPOWERDOWNCONTROL, 0),
-			     1);
+	err = ufs_mtk_unipro_powerdown(hba, 1);
 	if (err) {
 		/* Resume UniPro state for following error recovery */
-		ufshcd_dme_set(hba,
-			       UIC_ARG_MIB_SEL(VS_UNIPROPOWERDOWNCONTROL, 0),
-			       0);
+		ufs_mtk_unipro_powerdown(hba, 0);
 		return err;
 	}