linux-kernel - Re: [PATCH RESEND] scsi: ufs: Add checking lifetime attribute for WriteBooster

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Date:   Fri, 28 Jan 2022 08:05:02 -0800
From:   Asutosh Das <quic_asutoshd@...cinc.com>
To:     Jinyoung CHOI <j-young.choi@...sung.com>
CC:     ALIM AKHTAR <alim.akhtar@...sung.com>,
        "avri.altman@....com" <avri.altman@....com>,
        "jejb@...ux.ibm.com" <jejb@...ux.ibm.com>,
        "martin.petersen@...cle.com" <martin.petersen@...cle.com>,
        "bvanassche@....org" <bvanassche@....org>,
        "cang@...eaurora.org" <cang@...eaurora.org>,
        "adrian.hunter@...el.com" <adrian.hunter@...el.com>,
        "asutoshd@...eaurora.org" <asutoshd@...eaurora.org>,
        "linux-scsi@...r.kernel.org" <linux-scsi@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "huobean@...il.com" <huobean@...il.com>
Subject: Re: [PATCH RESEND] scsi: ufs: Add checking lifetime attribute for
 WriteBooster

On Thu, Jan 27 2022 at 19:07 -0800, Jinyoung CHOI wrote:
>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@...sung.com>
>---

LGTM.

Reviewed-by: Asutosh Das <quic_asutoshd@...cinc.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..41d85b69fa50 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%02X\n",
>+			__func__, lifetime);
>+		return false;
>+	}
>+
>+	dev_dbg(hba->dev, "%s: WB buf lifetime is 0x%02X\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