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From:   Stanley Chu <stanley.chu@mediatek.com>
To:     <linux-scsi@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <martin.petersen@oracle.com>, <avri.altman@wdc.com>,
        <alim.akhtar@samsung.com>, <jejb@linux.ibm.com>,
        <bvanassche@acm.org>
CC:     <peter.wang@mediatek.com>, <chun-hung.wu@mediatek.com>,
        <alice.chao@mediatek.com>, <powen.kao@mediatek.com>,
        <mason.zhang@mediatek.com>, <qilin.tan@mediatek.com>,
        <lin.gui@mediatek.com>, <eddie.huang@mediatek.com>,
        <tun-yu.yu@mediatek.com>, <cc.chou@mediatek.com>,
        <chaotian.jing@mediatek.com>, <jiajie.hao@mediatek.com>,
        <stanley.chu@mediatek.com>
Subject: [PATCH v1] scsi: ufs: Fix ufshcd_scale_clks decision in recovery flow
Date:   Fri, 29 Jul 2022 15:55:19 +0800
Message-ID: <20220729075519.4665-1-stanley.chu@mediatek.com>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

When someone toggles clk-scaling feature via sysfs interface,
the flag "hba->clk_scaling.is_enabled" shall be changed after
ufshcd_devfreq_scale() is finished.

By this change, we can use this flag to make right decision for
invoking ufshcd_scale_clks() in host recovery flow, i.e., in
ufshcd_host_reset_and_restore().

ufshcd_scale_clks() shall be invoked only if both conditions
are satisfied,

1. Clk-scaling is supported, and
2. Clk-scaling is enabled

Otherwise, the clk and gear which would be scaled by
ufshcd_scale_clks() shall be already in the default state
so the scaling is not required anymore.

Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
---
 drivers/ufs/core/ufshcd.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index 581d88af07ab..dc57a7988023 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -1574,8 +1574,6 @@ static ssize_t ufshcd_clkscale_enable_store(struct device *dev,
 	ufshcd_rpm_get_sync(hba);
 	ufshcd_hold(hba, false);
 
-	hba->clk_scaling.is_enabled = value;
-
 	if (value) {
 		ufshcd_resume_clkscaling(hba);
 	} else {
@@ -1586,6 +1584,8 @@ static ssize_t ufshcd_clkscale_enable_store(struct device *dev,
 					__func__, err);
 	}
 
+	hba->clk_scaling.is_enabled = value;
+
 	ufshcd_release(hba);
 	ufshcd_rpm_put_sync(hba);
 out:
@@ -7259,7 +7259,8 @@ static int ufshcd_host_reset_and_restore(struct ufs_hba *hba)
 	hba->silence_err_logs = false;
 
 	/* scale up clocks to max frequency before full reinitialization */
-	ufshcd_scale_clks(hba, true);
+	if (ufshcd_is_clkscaling_supported(hba) && hba->clk_scaling.is_enabled)
+		ufshcd_scale_clks(hba, true);
 
 	err = ufshcd_hba_enable(hba);
 
-- 
2.18.0