linux-kernel - [PATCH v2 1/3] scsi: ufshcd: Update the set frequency to devfreq

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Date:   Wed, 25 Mar 2020 11:29:00 -0700
From:   Asutosh Das <asutoshd@...eaurora.org>
To:     Avri.Altman@....com, cang@...eaurora.org,
        martin.petersen@...cle.com, linux-scsi@...r.kernel.org
Cc:     Asutosh Das <asutoshd@...eaurora.org>,
        linux-arm-msm@...r.kernel.org,
        Alim Akhtar <alim.akhtar@...sung.com>,
        Avri Altman <avri.altman@....com>,
        "James E.J. Bottomley" <jejb@...ux.ibm.com>,
        Stanley Chu <stanley.chu@...iatek.com>,
        Bean Huo <beanhuo@...ron.com>,
        Bart Van Assche <bvanassche@....org>,
        Venkat Gopalakrishnan <venkatg@...eaurora.org>,
        Tomas Winkler <tomas.winkler@...el.com>,
        linux-kernel@...r.kernel.org (open list)
Subject: [PATCH v2 1/3] scsi: ufshcd: Update the set frequency to devfreq

Currently, the frequency that devfreq provides the
driver to set always leads the clocks to be scaled up.
Hence, round the clock-rate to the nearest frequency
before deciding to scale.

Also update the devfreq statistics of current frequency.

Signed-off-by: Asutosh Das <asutoshd@...eaurora.org>
---
 drivers/scsi/ufs/ufshcd.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 2a2a63b..7916c8b 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -1187,6 +1187,9 @@ static int ufshcd_devfreq_target(struct device *dev,
 	if (!ufshcd_is_clkscaling_supported(hba))
 		return -EINVAL;
 
+	clki = list_first_entry(&hba->clk_list_head, struct ufs_clk_info, list);
+	/* Override with the closest supported frequency */
+	*freq = (unsigned long) clk_round_rate(clki->clk, *freq);
 	spin_lock_irqsave(hba->host->host_lock, irq_flags);
 	if (ufshcd_eh_in_progress(hba)) {
 		spin_unlock_irqrestore(hba->host->host_lock, irq_flags);
@@ -1201,8 +1204,11 @@ static int ufshcd_devfreq_target(struct device *dev,
 		goto out;
 	}
 
-	clki = list_first_entry(&hba->clk_list_head, struct ufs_clk_info, list);
+	/* Decide based on the rounded-off frequency and update */
 	scale_up = (*freq == clki->max_freq) ? true : false;
+	if (!scale_up)
+		*freq = clki->min_freq;
+	/* Update the frequency */
 	if (!ufshcd_is_devfreq_scaling_required(hba, scale_up)) {
 		spin_unlock_irqrestore(hba->host->host_lock, irq_flags);
 		ret = 0;
@@ -1250,6 +1256,8 @@ static int ufshcd_devfreq_get_dev_status(struct device *dev,
 	struct ufs_hba *hba = dev_get_drvdata(dev);
 	struct ufs_clk_scaling *scaling = &hba->clk_scaling;
 	unsigned long flags;
+	struct list_head *clk_list = &hba->clk_list_head;
+	struct ufs_clk_info *clki;
 
 	if (!ufshcd_is_clkscaling_supported(hba))
 		return -EINVAL;
@@ -1260,6 +1268,13 @@ static int ufshcd_devfreq_get_dev_status(struct device *dev,
 	if (!scaling->window_start_t)
 		goto start_window;
 
+	clki = list_first_entry(clk_list, struct ufs_clk_info, list);
+	/*
+	 * If current frequency is 0, then the ondemand governor considers
+	 * there's no initial frequency set. And it always requests to set
+	 * to max. frequency.
+	 */
+	stat->current_frequency = clki->curr_freq;
 	if (scaling->is_busy_started)
 		scaling->tot_busy_t += ktime_to_us(ktime_sub(ktime_get(),
 					scaling->busy_start_t));
-- 
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