[PATCH] scsi: ufs: Add checking lifetime attribute for WriteBooster

[PATCH] scsi: ufs: Add checking lifetime attribute for WriteBooster

[Jinyoung CHOI]

Because WB performs write in SLC mode, it is difficult to use WB
infinitely.

Vendors can set the Lifetime limit value to the device.
If Lifetime exceeds the limit value, the device itself can disable the
WB feature.

WB feature supports "bWriteBoosterBufferLifeTimeEst (IDN = 1E)" attribute.

With Lifetime exceeding the limit value,
the current driver continuously performs the following query.

	- Write Flag: WB_ENABLE / DISABLE
	- Read attr: Available Buffer Size
	- Read attr: Current Buffer Size

This patch recognizes that WriteBooster is no longer supported by the device,
and prevent unnecessary query issues.

Signed-off-by: Jinyoung Choi <j-young.choi@samsung.com>
---
 drivers/scsi/ufs/ufs.h    |  6 +++++
 drivers/scsi/ufs/ufshcd.c | 52 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 58 insertions(+)

diff --git a/drivers/scsi/ufs/ufs.h b/drivers/scsi/ufs/ufs.h
index 0bfdca3e648e..4a00c24a3209 100644
--- a/drivers/scsi/ufs/ufs.h
+++ b/drivers/scsi/ufs/ufs.h
@@ -43,6 +43,12 @@
 /* WriteBooster buffer is available only for the logical unit from 0 to 7 */
 #define UFS_UPIU_MAX_WB_LUN_ID	8
 
+/*
+ * WriteBooster buffer lifetime has a limit setted by vendor.
+ * If it is over the limit, WriteBooster feature will be disabled.
+ */
+#define UFS_WB_EXCEED_LIFETIME		0x0B
+
 /* Well known logical unit id in LUN field of UPIU */
 enum {
 	UFS_UPIU_REPORT_LUNS_WLUN	= 0x81,
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 460d2b440d2e..6088af45633b 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -5778,6 +5778,47 @@ static bool ufshcd_wb_presrv_usrspc_keep_vcc_on(struct ufs_hba *hba,
 	return false;
 }
 
+static void ufshcd_wb_force_disable(struct ufs_hba *hba)
+{
+	if (!(hba->quirks & UFSHCI_QUIRK_SKIP_MANUAL_WB_FLUSH_CTRL))
+		ufshcd_wb_toggle_flush(hba, false);
+
+	ufshcd_wb_toggle_flush_during_h8(hba, false);
+	ufshcd_wb_toggle(hba, false);
+	hba->caps &= ~UFSHCD_CAP_WB_EN;
+
+	dev_info(hba->dev, "%s: WB force disabled\n", __func__);
+}
+
+static bool ufshcd_is_wb_buf_lifetime_available(struct ufs_hba *hba)
+{
+	u32 lifetime;
+	int ret;
+	u8 index;
+
+	index = ufshcd_wb_get_query_index(hba);
+	ret = ufshcd_query_attr_retry(hba, UPIU_QUERY_OPCODE_READ_ATTR,
+				      QUERY_ATTR_IDN_WB_BUFF_LIFE_TIME_EST,
+				      index, 0, &lifetime);
+	if (ret) {
+		dev_err(hba->dev,
+			"%s: bWriteBoosterBufferLifeTimeEst read failed %d\n",
+			__func__, ret);
+		return false;
+	}
+
+	if (lifetime == UFS_WB_EXCEED_LIFETIME) {
+		dev_err(hba->dev, "%s: WB buf lifetime is exhausted 0x%0.2X\n",
+			__func__, lifetime);
+		return false;
+	}
+
+	dev_dbg(hba->dev, "%s: WB buf lifetime is 0x%0.2X\n",
+		__func__, lifetime);
+
+	return true;
+}
+
 static bool ufshcd_wb_need_flush(struct ufs_hba *hba)
 {
 	int ret;
@@ -5786,6 +5827,12 @@ static bool ufshcd_wb_need_flush(struct ufs_hba *hba)
 
 	if (!ufshcd_is_wb_allowed(hba))
 		return false;
+
+	if (!ufshcd_is_wb_buf_lifetime_available(hba)) {
+		ufshcd_wb_force_disable(hba);
+		return false;
+	}
+
 	/*
 	 * The ufs device needs the vcc to be ON to flush.
 	 * With user-space reduction enabled, it's enough to enable flush
@@ -7486,6 +7533,7 @@ static void ufshcd_wb_probe(struct ufs_hba *hba, u8 *desc_buf)
 
 	if (!ufshcd_is_wb_allowed(hba))
 		return;
+
 	/*
 	 * Probe WB only for UFS-2.2 and UFS-3.1 (and later) devices or
 	 * UFS devices with quirk UFS_DEVICE_QUIRK_SUPPORT_EXTENDED_FEATURES
@@ -7537,6 +7585,10 @@ static void ufshcd_wb_probe(struct ufs_hba *hba, u8 *desc_buf)
 		if (!d_lu_wb_buf_alloc)
 			goto wb_disabled;
 	}
+
+	if (!ufshcd_is_wb_buf_lifetime_available(hba))
+		goto wb_disabled;
+
 	return;
 
 wb_disabled:
-- 
2.25.1