scsi: ufs: scale up the gear in 2 steps

Some UFS devices may stop responding after switching from HS-G1 to HS-G3.
Also, it is found that these devices work fine if we do 2 steps switch:
HS-G1 to HS-G2 followed by HS-G2 to HS-G3.
This change introduce UFS_DEVICE_QUIRK_HS_G1_TO_HS_G3_SWITCH quirk for
these devices to apply this 2 steps gear switch workaround.

Change-Id: I38eec2e1bfa842169cbfec441d900a807e715f8c
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>

3 files changed, 53 insertions, 6 deletions

diff --git a/drivers/scsi/ufs/ufs_quirks.c b/drivers/scsi/ufs/ufs_quirks.c
index 176c3888aa34..7a501d6d7c84 100644
--- a/drivers/scsi/ufs/ufs_quirks.c
+++ b/drivers/scsi/ufs/ufs_quirks.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013-2015, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2013-2017, The Linux Foundation. All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 and
@@ -30,6 +30,20 @@ static struct ufs_card_fix ufs_fixups[] = {
 		UFS_DEVICE_QUIRK_HOST_PA_TACTIVATE),
 	UFS_FIX(UFS_VENDOR_HYNIX, UFS_ANY_MODEL,
 		UFS_DEVICE_QUIRK_HOST_PA_SAVECONFIGTIME),
+	UFS_FIX(UFS_VENDOR_HYNIX, "hB8aL1",
+		UFS_DEVICE_QUIRK_HS_G1_TO_HS_G3_SWITCH),
+	UFS_FIX(UFS_VENDOR_HYNIX, "hC8aL1",
+		UFS_DEVICE_QUIRK_HS_G1_TO_HS_G3_SWITCH),
+	UFS_FIX(UFS_VENDOR_HYNIX, "hD8aL1",
+		UFS_DEVICE_QUIRK_HS_G1_TO_HS_G3_SWITCH),
+	UFS_FIX(UFS_VENDOR_HYNIX, "hC8aM1",
+		UFS_DEVICE_QUIRK_HS_G1_TO_HS_G3_SWITCH),
+	UFS_FIX(UFS_VENDOR_HYNIX, "h08aM1",
+		UFS_DEVICE_QUIRK_HS_G1_TO_HS_G3_SWITCH),
+	UFS_FIX(UFS_VENDOR_HYNIX, "hC8GL1",
+		UFS_DEVICE_QUIRK_HS_G1_TO_HS_G3_SWITCH),
+	UFS_FIX(UFS_VENDOR_HYNIX, "hC8HL1",
+		UFS_DEVICE_QUIRK_HS_G1_TO_HS_G3_SWITCH),
 
 	END_FIX
 };
diff --git a/drivers/scsi/ufs/ufs_quirks.h b/drivers/scsi/ufs/ufs_quirks.h
index b8ab5948f12d..3102517e841c 100644
--- a/drivers/scsi/ufs/ufs_quirks.h
+++ b/drivers/scsi/ufs/ufs_quirks.h
@@ -1,4 +1,4 @@
-/* Copyright (c) 2014-2015, The Linux Foundation. All rights reserved.
+/* Copyright (c) 2014-2017, The Linux Foundation. All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 and
@@ -139,6 +139,14 @@ struct ufs_card_fix {
  */
 #define UFS_DEVICE_QUIRK_HOST_PA_SAVECONFIGTIME	(1 << 7)
 
+/*
+ * Some UFS devices may stop responding after switching from HS-G1 to HS-G3.
+ * Also, it is found that these devices work fine if we do 2 steps switch:
+ * HS-G1 to HS-G2 followed by HS-G2 to HS-G3. Enabling this quirk for such
+ * device would apply this 2 steps gear switch workaround.
+ */
+#define UFS_DEVICE_QUIRK_HS_G1_TO_HS_G3_SWITCH (1 << 8)
+
 struct ufs_hba;
 void ufs_advertise_fixup_device(struct ufs_hba *hba);
 #endif /* UFS_QUIRKS_H_ */
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 2c46fd61fa47..a02c8a2c756c 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -509,7 +509,7 @@ out:
 /* replace non-printable or non-ASCII characters with spaces */
 static inline void ufshcd_remove_non_printable(char *val)
 {
-	if (!val)
+	if (!val || !*val)
 		return;
 
 	if (*val < 0x20 || *val > 0x7e)
@@ -3651,7 +3651,7 @@ int ufshcd_read_string_desc(struct ufs_hba *hba, int desc_index, u8 *buf,
 			goto out;
 		}
 
-		buff_ascii = kmalloc(ascii_len, GFP_KERNEL);
+		buff_ascii = kzalloc(ascii_len, GFP_KERNEL);
 		if (!buff_ascii) {
 			dev_err(hba->dev, "%s: Failed allocating %d bytes\n",
 					__func__, ascii_len);
@@ -9207,6 +9207,31 @@ static int ufshcd_scale_gear(struct ufs_hba *hba, bool scale_up)
 	if (scale_up) {
 		memcpy(&new_pwr_info, &hba->clk_scaling.saved_pwr_info.info,
 		       sizeof(struct ufs_pa_layer_attr));
+		/*
+		 * Some UFS devices may stop responding after switching from
+		 * HS-G1 to HS-G3. Also, it is found that these devices work
+		 * fine if we do 2 steps switch: HS-G1 to HS-G2 followed by
+		 * HS-G2 to HS-G3. If UFS_DEVICE_QUIRK_HS_G1_TO_HS_G3_SWITCH
+		 * quirk is enabled for such devices, this 2 steps gear switch
+		 * workaround will be applied.
+		 */
+		if ((hba->dev_quirks & UFS_DEVICE_QUIRK_HS_G1_TO_HS_G3_SWITCH)
+		    && (hba->pwr_info.gear_tx == UFS_HS_G1)
+		    && (new_pwr_info.gear_tx == UFS_HS_G3)) {
+			/* scale up to G2 first */
+			new_pwr_info.gear_tx = UFS_HS_G2;
+			new_pwr_info.gear_rx = UFS_HS_G2;
+			ret = ufshcd_change_power_mode(hba, &new_pwr_info);
+			if (ret)
+				goto out;
+
+			/* scale up to G3 now */
+			new_pwr_info.gear_tx = UFS_HS_G3;
+			new_pwr_info.gear_rx = UFS_HS_G3;
+			ret = ufshcd_change_power_mode(hba, &new_pwr_info);
+			if (ret)
+				goto out;
+		}
 	} else {
 		memcpy(&new_pwr_info, &hba->pwr_info,
 		       sizeof(struct ufs_pa_layer_attr));
@@ -9226,10 +9251,10 @@ static int ufshcd_scale_gear(struct ufs_hba *hba, bool scale_up)
 				new_pwr_info.pwr_rx = FASTAUTO_MODE;
 			}
 		}
+		ret = ufshcd_change_power_mode(hba, &new_pwr_info);
 	}
 
-	ret = ufshcd_change_power_mode(hba, &new_pwr_info);
-
+out:
 	if (ret)
 		dev_err(hba->dev, "%s: failed err %d, old gear: (tx %d rx %d), new gear: (tx %d rx %d), scale_up = %d",
 			__func__, ret,