scsi: ufshcd: Update the set frequency to devfreq

Currently, the frequency that devfreq provides the driver 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.

Link: https://lore.kernel.org/r/d0c6c22455811e9f0eda01f9bc70d1398b51b2bd.1585160616.git.asutoshd@codeaurora.org
Acked-by: Avri Altman <[email protected]>
Signed-off-by: Asutosh Das <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>

drivers/scsi/ufs/ufshcd.c

@@ -1199,6 +1199,9 @@ 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);
@@ -1213,8 +1216,11 @@ 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;
@@ -1262,6 +1268,8 @@ 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;
@@ -1272,6 +1280,13 @@ 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));