scsi: ufs: core: Toggle Write Booster during clock scaling base on gear speed

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.

Signed-off-by: Can Guo <quic_cang@quicinc.com>
Co-developed-by: Ziqi Chen <quic_ziqichen@quicinc.com>
Signed-off-by: Ziqi Chen <quic_ziqichen@quicinc.com>
Link: https://lore.kernel.org/r/20250213080008.2984807-8-quic_ziqichen@quicinc.com
Reviewed-by: Bean Huo <beanhuo@micron.com>
Tested-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Peter Wang <peter.wang@mediatek.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index e59ce8e5509ed1ce959031c8fbc1fbed1ae6e56b..35a5e2842b5bb3978dcea0f01fbe414eadbe5e95 100644 (file)
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -1398,13 +1398,13 @@ out:
        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 */
+       /* Enable Write Booster if current gear requires it else disable it */
        if (ufshcd_enable_wb_if_scaling_up(hba) && !err)
-               ufshcd_wb_toggle(hba, scale_up);
+               ufshcd_wb_toggle(hba, hba->pwr_info.gear_rx >= hba->clk_scaling.wb_gear);
 
        mutex_unlock(&hba->wb_mutex);
 
@@ -1459,7 +1459,7 @@ 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;
 }
 
@@ -1811,6 +1811,10 @@ 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)
+               /* Use intermediate gear speed HS_G3 as the default 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 199c2cec29d0b598d6ce91e99c4eb9eeb9bb7060..1b9f72ea4c1c343de2b49024fd77465dec1c826b 100644 (file)
--- a/include/ufs/ufshcd.h
+++ b/include/ufs/ufshcd.h
@@ -450,6 +450,8 @@ struct ufs_clk_gating {
  * one keeps track of previous power mode.
  * @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
@@ -473,6 +475,7 @@ struct ufs_clk_scaling {
        struct ufs_pa_layer_attr saved_pwr_info;
        unsigned long target_freq;
        u32 min_gear;
+       u32 wb_gear;
        bool is_enabled;
        bool is_allowed;
        bool is_initialized;