linux-kernel - [PATCH 3/3] scsi: ufs: core: Add support for frequency PM QoS tuning

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Message-Id: <20250914114549.650671-4-wangjianzheng@vivo.com>
Date: Sun, 14 Sep 2025 19:45:46 +0800
From: Wang Jianzheng <wangjianzheng@...o.com>
To: Jens Axboe <axboe@...nel.dk>,
	Alim Akhtar <alim.akhtar@...sung.com>,
	Avri Altman <avri.altman@....com>,
	Bart Van Assche <bvanassche@....org>,
	"James E.J. Bottomley" <James.Bottomley@...senPartnership.com>,
	"Martin K. Petersen" <martin.petersen@...cle.com>,
	"Rafael J. Wysocki" <rafael@...nel.org>,
	Peter Wang <peter.wang@...iatek.com>,
	Bean Huo <beanhuo@...ron.com>,
	"Bao D. Nguyen" <quic_nguyenb@...cinc.com>,
	Adrian Hunter <adrian.hunter@...el.com>,
	linux-block@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-scsi@...r.kernel.org,
	linux-pm@...r.kernel.org
Cc: Wang Jianzheng <wangjianzheng@...o.com>
Subject: [PATCH 3/3] scsi: ufs: core: Add support for frequency PM QoS tuning

During frequency scaling operations, the host can reads the frequency
constraint configured in the PM QoS framework and updates the target
frequency accordingly.

Signed-off-by: Wang Jianzheng <wangjianzheng@...o.com>
---
 drivers/ufs/core/ufshcd.c | 44 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 44 insertions(+)

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index 9a43102b2b21..1a9bcbc9dab0 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -1546,6 +1546,47 @@ static void ufshcd_clk_scaling_resume_work(struct work_struct *work)
 	devfreq_resume_device(hba->devfreq);
 }
 
+#ifdef CONFIG_PM
+static void ufshcd_pm_qos_freq_read_value(struct ufs_hba *hba,
+					   unsigned long *freq)
+{
+	struct Scsi_Host *shost = hba->host;
+	struct scsi_device *sdev;
+	struct request_queue *q;
+	struct ufs_clk_info *clki;
+	s32 min_qos_freq;
+
+	if (!shost)
+		return;
+
+	shost_for_each_device(sdev, shost) {
+		if (!sdev)
+			continue;
+
+		q = sdev->request_queue;
+		if (IS_ERR_OR_NULL(q))
+			continue;
+
+		if (q->disk && !IS_ERR_OR_NULL(q->dev)) {
+			if (q->disk->dev_freq_timeout) {
+				min_qos_freq = dev_pm_qos_read_value(q->dev,
+								     DEV_PM_QOS_MIN_FREQUENCY);
+				clki = list_first_entry(&hba->clk_list_head,
+							struct ufs_clk_info, list);
+				if (min_qos_freq > clki->max_freq)
+					*freq = clki->max_freq;
+			}
+		}
+	}
+}
+#else
+static void ufshcd_pm_qos_freq_read_value(struct ufs_hba *hba,
+					   unsigned long *freq)
+{
+	return;
+}
+#endif
+
 static int ufshcd_devfreq_target(struct device *dev,
 				unsigned long *freq, u32 flags)
 {
@@ -1559,6 +1600,9 @@ static int ufshcd_devfreq_target(struct device *dev,
 	if (!ufshcd_is_clkscaling_supported(hba))
 		return -EINVAL;
 
+	/* Select the frequency based on the DEV_PM_QOS_MIN_FREQUENCY */
+	ufshcd_pm_qos_freq_read_value(hba, freq);
+
 	if (hba->use_pm_opp) {
 		struct dev_pm_opp *opp;
 
-- 
2.34.1