0020-scsi-ufs-turbo-write-Align-to-QCOM-pm-convention.patch

From 42314026ac72970916fde895b111bbb2ed3e1ea3 Mon Sep 17 00:00:00 2001
From: Avri Altman <avri.altman@wdc.com>
Date: Sat, 6 Apr 2019 12:33:02 +0300
Subject: [PATCH 20/25] scsi: ufs: turbo-write: Align to QCOM pm convention

QCOM relates to turbo-write buffer flushing much like urgent bkops.
According to their runtime suspend flow (enter after 3msec idle),
a deeper sleep state that involve sending SSU is enabled only if urgent
bkops is not needed.

Now that turbo-write is in play - treat it just the same: send SSU
if urgent bkops is not needed, nor urgent turbo-write flush is needed.
They define this critical threshold to be 70% of the turbo-write buffer.

Checking that the turbo-write buffer might not be enough. If the rest of
the user area is full, the device is not able to fold the content of the
turbo-write buffer anyway, so need to check The
bTurboWriteBufferFlushStatus attribute as well. Add a TODO so we'll keep
this in mind.

Change-Id: I66f7f939b0b154358e5720e328f9d501ebac05e4
Signed-off-by: Avri Altman <avri.altman@wdc.com>
---
 drivers/scsi/ufs/ufshcd.c | 47 ++++++++++++++++++++++++++++++++++++++++++++++-
 drivers/scsi/ufs/ufshcd.h |  3 +++
 2 files changed, 49 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 87881e5..bceebb8 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -5054,6 +5054,7 @@ static int ufshcd_get_tw_mode(struct ufs_hba *hba, u8 *desc_buf)
 	hba->tw_size = val;
 	err = ufshcd_turbo_write_enable_flush_on_hibern8(hba);
 	atomic_set(&hba->tw_urgent_flush_ref, 0);
+	hba->tw_urgent_flush_lvl = 3;
 
 out:
 	if (err)
@@ -6343,6 +6344,45 @@ static int ufshcd_verify_dev_init(struct ufs_hba *hba)
 	return err;
 }
 
+static inline int ufshcd_get_tw_buffer_status(struct ufs_hba *hba, u32 *status)
+{
+	return ufshcd_query_attr_retry(hba, UPIU_QUERY_OPCODE_READ_ATTR,
+				       QUERY_ATTR_IDN_TW_AVAIL_BUF_SIZE, 0, 0,
+				       status);
+}
+
+static int ufshcd_tw_flush_ctrl(struct ufs_hba *hba)
+{
+	int err;
+	u32 lvl = 0;
+
+	if (!ufshcd_is_tw_supported(hba))
+		return -EOPNOTSUPP;
+
+	err = ufshcd_get_tw_buffer_status(hba, &lvl);
+	if (err) {
+		dev_err(hba->dev, "failed to get tw buffer status %d\n", err);
+		goto out;
+	} else if (lvl > UFS_TW_BUFFER_LVL_MAX) {
+		dev_err(hba->dev, "invalid tw buffer status %d\n", lvl);
+		err = -EINVAL;
+		goto out;
+	}
+
+	/* TODO: Checking that the turbo-write buffer might not be enough.
+	 * If the rest of the user area is full, the device is not able to fold
+	 * the content of the turbo-write buffer anyway, so need to check the
+	 * bTurboWriteBufferFlushStatus attribute as well.
+	 * Leave it as it is for now.
+	 */
+	if (lvl <= hba->tw_urgent_flush_lvl)
+		err = ufshcd_turbo_write_enable_flush_on_hibern8(hba);
+	else
+		err = ufshcd_turbo_write_disable_flush_on_hibern8(hba);
+out:
+	return err;
+}
+
 static void ufshcd_turbo_write_exception_event_handler(struct ufs_hba *hba)
 {
 
@@ -10781,6 +10821,7 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
 	enum ufs_pm_level pm_lvl;
 	enum ufs_dev_pwr_mode req_dev_pwr_mode;
 	enum uic_link_state req_link_state;
+	bool tw_flush_enabled = false;
 
 	hba->pm_op_in_progress = 1;
 	if (!ufshcd_is_shutdown_pm(pm_op)) {
@@ -10836,11 +10877,15 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
 			/* make sure that auto bkops is disabled */
 			ufshcd_disable_auto_bkops(hba);
 		}
-		ufshcd_turbo_write_enable_flush_on_hibern8(hba);
+		ret = ufshcd_tw_flush_ctrl(hba);
+		if (ret)
+			goto enable_gating;
+		tw_flush_enabled = hba->tw_flush & UFS_TW_FLUSH_HIBERN8;
 	}
 
 	if ((req_dev_pwr_mode != hba->curr_dev_pwr_mode) &&
 	     ((ufshcd_is_runtime_pm(pm_op) && !hba->auto_bkops_enabled) ||
+	      (ufshcd_is_runtime_pm(pm_op) && !tw_flush_enabled) ||
 	       !ufshcd_is_runtime_pm(pm_op))) {
 		/* ensure that bkops is disabled */
 		ufshcd_disable_auto_bkops(hba);
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index d3ed93e..56115b4 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -419,6 +419,8 @@ enum tw_flush_mode {
 	UFS_TW_FLUSH_HIBERN8		= BIT(1),
 };
 
+#define UFS_TW_BUFFER_LVL_MAX 10
+
 /* clock gating state  */
 enum clk_gating_state {
 	CLKS_OFF,
@@ -1077,6 +1079,7 @@ struct ufs_hba {
 	int tw_flush;
 	bool tw_enabled;
 	atomic_t tw_urgent_flush_ref;
+	unsigned int tw_urgent_flush_lvl;
 };
 
 static inline void ufshcd_mark_shutdown_ongoing(struct ufs_hba *hba)
-- 
2.7.4