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ufs: allow host driver to disable wb toggling during clock scaling

PATCH New [email protected] 1 participant 1 message Aug 4, 2022

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SCSI Arm Qualcomm mailing list Arm MediaTek UFS host controller +1 more subsystems
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PATCH v5 1/1 ufs: allow host driver to disable wb toggling during clock scaling

From: Peter Wang <[email protected]>

Mediatek ufs do not want to toggle write booster during clock scaling. This patch allow host driver to disable wb toggling during clock scaling.

So, introduce a flag UFSHCD_CAP_WB_WITH_CLK_SCALING to decouple WB and clock scaling. UFSHCD_CAP_WB_WITH_CLK_SCALING only valid when UFSHCD_CAP_CLK_SCALING is set. Just like UFSHCD_CAP_HIBERN8_WITH_CLK_GATING is valid only when UFSHCD_CAP_CLK_GATING set.

Set UFSHCD_CAP_WB_WITH_CLK_SCALING for qcom to compatible legacy design in the same time.

Signed-off-by Peter Wang <[email protected]>
Reviewed-by Stanley Chu <[email protected]>
---
 drivers/ufs/core/ufs-sysfs.c |  3 ++-
 drivers/ufs/core/ufshcd.c    |  8 +++++---
 drivers/ufs/host/ufs-qcom.c  |  2 +-
 include/ufs/ufshcd.h         | 11 +++++++++++
 4 files changed, 19 insertions(+), 5 deletions(-)
drivers/ufs/core/ufs-sysfs.c +2 -1
index 0a088b47d557..7f41f2a69b04 100644
@@ -225,7 +225,8 @@ static ssize_t wb_on_store(struct device *dev, struct
 device_attribute *attr,
 	unsigned int wb_enable;
 	ssize_t res;
 
-	if (!ufshcd_is_wb_allowed(hba) || ufshcd_is_clkscaling_supported(hba)) {
+	if (!ufshcd_is_wb_allowed(hba) || (ufshcd_is_clkscaling_supported(hba)
+		&& ufshcd_enable_wb_if_scaling_up(hba))) {
 		/*
 		 * If the platform supports UFSHCD_CAP_CLK_SCALING, turn WB

* on/off will be done while clock scaling up/down.

drivers/ufs/core/ufshcd.c +5 -3
index c7b337480e3e..ac50fbe8aeb8 100644
@@ -1301,9 +1301,11 @@ static int ufshcd_devfreq_scale(struct ufs_hba *hba,
 bool scale_up)
 	}
 
 	/* Enable Write Booster if we have scaled up else disable it */
-	downgrade_write(&hba->clk_scaling_lock);
-	is_writelock = false;
-	ufshcd_wb_toggle(hba, scale_up);
+	if (ufshcd_enable_wb_if_scaling_up(hba)) {
+		downgrade_write(&hba->clk_scaling_lock);
+		is_writelock = false;
+		ufshcd_wb_toggle(hba, scale_up);
+	}
 
 out_unprepare:

ufshcd_clock_scaling_unprepare(hba, is_writelock);

drivers/ufs/host/ufs-qcom.c +1 -1
index f10d4668814c..f8c9a78e7776 100644
@@ -869,7 +869,7 @@ static void ufs_qcom_set_caps(struct ufs_hba *hba)
 	struct ufs_qcom_host *host = ufshcd_get_variant(hba);
 
 	hba->caps |= UFSHCD_CAP_CLK_GATING | UFSHCD_CAP_HIBERN8_WITH_CLK_GATING;
-	hba->caps |= UFSHCD_CAP_CLK_SCALING;
+	hba->caps |= UFSHCD_CAP_CLK_SCALING | UFSHCD_CAP_WB_WITH_CLK_SCALING;
 	hba->caps |= UFSHCD_CAP_AUTO_BKOPS_SUSPEND;
 	hba->caps |= UFSHCD_CAP_WB_EN;
 	hba->caps |= UFSHCD_CAP_CRYPTO;
include/ufs/ufshcd.h +11 -0
index a92271421718..bed6fb1da78d 100644
@@ -648,6 +648,12 @@ enum ufshcd_caps {
 	 * notification if it is supported by the UFS device.
 	 */
 	UFSHCD_CAP_TEMP_NOTIF				= 1 << 11,
+
+	/*
+	 * Enable WriteBooster when scaling up the clock and disable
+	 * WriteBooster when scaling the clock down.
+	 */
+	UFSHCD_CAP_WB_WITH_CLK_SCALING			= 1 << 12,
 };
 
 struct ufs_hba_variant_params {

@@ -1005,6 +1011,11 @@ static inline bool ufshcd_is_wb_allowed(struct
 ufs_hba *hba)
 	return hba->caps & UFSHCD_CAP_WB_EN;
 }
 
+static inline bool ufshcd_enable_wb_if_scaling_up(struct ufs_hba *hba)
+{
+	return hba->caps & UFSHCD_CAP_WB_WITH_CLK_SCALING;
+}
+
 #define ufshcd_writel(hba, val, reg)	\
 	writel((val), (hba)->mmio_base + (reg))

#define ufshcd_readl(hba, reg) \

Signature · 1 line
2.18.0