linux-kernel - [PATCH 7/8] scsi: ufs: core: Toggle Write Booster during clock scaling base on gear speed

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Message-Id: <20250116091150.1167739-8-quic_ziqichen@quicinc.com>
Date: Thu, 16 Jan 2025 17:11:48 +0800
From: Ziqi Chen <quic_ziqichen@...cinc.com>
To: quic_cang@...cinc.com, bvanassche@....org, mani@...nel.org,
        beanhuo@...ron.com, avri.altman@....com, junwoo80.lee@...sung.com,
        martin.petersen@...cle.com, quic_ziqichen@...cinc.com,
        quic_nguyenb@...cinc.com, quic_nitirawa@...cinc.com,
        quic_rampraka@...cinc.com
Cc: linux-scsi@...r.kernel.org, Alim Akhtar <alim.akhtar@...sung.com>,
        "James E.J. Bottomley" <James.Bottomley@...senPartnership.com>,
        Peter Wang <peter.wang@...iatek.com>,
        Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>,
        Andrew Halaney <ahalaney@...hat.com>,
        Maramaina Naresh <quic_mnaresh@...cinc.com>,
        Eric Biggers <ebiggers@...gle.com>, Minwoo Im <minwoo.im@...sung.com>,
        linux-kernel@...r.kernel.org (open list)
Subject: [PATCH 7/8] scsi: ufs: core: Toggle Write Booster during clock scaling base on gear speed

From: Can Guo <quic_cang@...cinc.com>

During clock scaling, Write Booster is toggled on or off based on
whether the clock is scaled up or down. However, with OPP V2 powered
multi-level gear scaling, the gear can be scaled amongst multiple gear
speeds, e.g., it may scale down from G5 to G4, or from G4 to G2. To provide
flexibilities, add a new field for clock scaling such that during clock
scaling Write Booster can be enabled or disabled based on gear speeds but
not based on scaling up or down.

Co-developed-by: Ziqi Chen <quic_ziqichen@...cinc.com>
Signed-off-by: Ziqi Chen <quic_ziqichen@...cinc.com>
Signed-off-by: Can Guo <quic_cang@...cinc.com>
---
 drivers/ufs/core/ufshcd.c | 17 ++++++++++++-----
 include/ufs/ufshcd.h      |  3 +++
 2 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index 721bf9d1a356..31ebf267135b 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -1395,13 +1395,17 @@ static int ufshcd_clock_scaling_prepare(struct ufs_hba *hba, u64 timeout_us)
 	return ret;
 }
 
-static void ufshcd_clock_scaling_unprepare(struct ufs_hba *hba, int err, bool scale_up)
+static void ufshcd_clock_scaling_unprepare(struct ufs_hba *hba, int err)
 {
 	up_write(&hba->clk_scaling_lock);
 
-	/* Enable Write Booster if we have scaled up else disable it */
-	if (ufshcd_enable_wb_if_scaling_up(hba) && !err)
-		ufshcd_wb_toggle(hba, scale_up);
+	/* Enable Write Booster if current gear requires it else disable it */
+	if (ufshcd_enable_wb_if_scaling_up(hba) && !err) {
+		bool wb_en;
+
+		wb_en = hba->pwr_info.gear_rx >= hba->clk_scaling.wb_gear ? true : false;
+		ufshcd_wb_toggle(hba, wb_en);
+	}
 
 	mutex_unlock(&hba->wb_mutex);
 
@@ -1456,7 +1460,7 @@ static int ufshcd_devfreq_scale(struct ufs_hba *hba, unsigned long freq,
 	}
 
 out_unprepare:
-	ufshcd_clock_scaling_unprepare(hba, ret, scale_up);
+	ufshcd_clock_scaling_unprepare(hba, ret);
 	return ret;
 }
 
@@ -1816,6 +1820,9 @@ static void ufshcd_init_clk_scaling(struct ufs_hba *hba)
 	if (!hba->clk_scaling.min_gear)
 		hba->clk_scaling.min_gear = UFS_HS_G1;
 
+	if (!hba->clk_scaling.wb_gear)
+		hba->clk_scaling.wb_gear = UFS_HS_G3;
+
 	INIT_WORK(&hba->clk_scaling.suspend_work,
 		  ufshcd_clk_scaling_suspend_work);
 	INIT_WORK(&hba->clk_scaling.resume_work,
diff --git a/include/ufs/ufshcd.h b/include/ufs/ufshcd.h
index 8c7c497d63d3..8e6c2eb68011 100644
--- a/include/ufs/ufshcd.h
+++ b/include/ufs/ufshcd.h
@@ -448,6 +448,8 @@ struct ufs_clk_gating {
  * @resume_work: worker to resume devfreq
  * @target_freq: frequency requested by devfreq framework
  * @min_gear: lowest HS gear to scale down to
+ * @wb_gear: enable Write Booster when HS gear scales above or equal to it, else
+ *		disable Write Booster
  * @is_enabled: tracks if scaling is currently enabled or not, controlled by
  *		clkscale_enable sysfs node
  * @is_allowed: tracks if scaling is currently allowed or not, used to block
@@ -468,6 +470,7 @@ struct ufs_clk_scaling {
 	struct work_struct resume_work;
 	unsigned long target_freq;
 	u32 min_gear;
+	u32 wb_gear;
 	bool is_enabled;
 	bool is_allowed;
 	bool is_initialized;
-- 
2.34.1