linux-kernel - Re: [PATCH v4 06/12] cpufreq: qcom: Update the bandwidth levels on frequency change

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Date:   Wed, 27 May 2020 09:35:59 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Sibi Sankar <sibis@...eaurora.org>
Cc:     sboyd@...nel.org, georgi.djakov@...aro.org,
        bjorn.andersson@...aro.org, saravanak@...gle.com, mka@...omium.org,
        nm@...com, agross@...nel.org, david.brown@...aro.org,
        robh+dt@...nel.org, mark.rutland@....com, rjw@...ysocki.net,
        linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        dianders@...omium.org, vincent.guittot@...aro.org,
        amit.kucheria@...aro.org, ulf.hansson@...aro.org,
        lukasz.luba@....com, sudeep.holla@....com
Subject: Re: [PATCH v4 06/12] cpufreq: qcom: Update the bandwidth levels on
 frequency change

On 27-05-20, 09:23, Viresh Kumar wrote:
> On 26-05-20, 23:18, Sibi Sankar wrote:
> > https://patchwork.kernel.org/cover/11548479/
> > GPU driver uses Georgi's series
> > for scaling and will need a way to
> > remove the icc votes in the suspend
> > path, (this looks like a pattern
> > that might be used by other clients
> > as well) I could probably update
> > opp_set_bw to support removing bw
> > when NULL opp is specified. Similarly
> > opp_set_rate will need to support
> > set bw to 0 when set_rate is passed
> > 0 as target freq for the same use case.
> 
> Sure, please send a patch for that.

On a second thought, here is the patch. Please test it.

-------------------------8<-------------------------

Subject: [PATCH] opp: Remove bandwidth votes when target_freq is zero

We already drop several votes when target_freq is set to zero, drop
bandwidth votes as well.

Reported-by: Sibi Sankar <sibis@...eaurora.org>
Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
---
 drivers/opp/core.c | 47 +++++++++++++++++++++++++++++++++++-----------
 1 file changed, 36 insertions(+), 11 deletions(-)

diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index 56d3022c1ca2..0c259d5ed232 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -725,6 +725,34 @@ static int _generic_set_opp_regulator(struct opp_table *opp_table,
 	return ret;
 }
 
+static int _set_opp_bw(const struct opp_table *opp_table,
+		       struct dev_pm_opp *opp, bool remove)
+{
+	u32 avg, peak;
+	int i, ret;
+
+	if (!opp_table->paths)
+		return 0;
+
+	for (i = 0; i < opp_table->path_count; i++) {
+		if (remove) {
+			avg = 0;
+			peak = 0;
+		} else {
+			avg = opp->bandwidth[i].avg;
+			peak = opp->bandwidth[i].peak;
+		}
+		ret = icc_set_bw(opp_table->paths[i], avg, peak);
+		if (ret) {
+			dev_err(dev, "Failed to %s bandwidth[%d]: %d\n",
+				remove ? "remove" : "set", i, ret);
+			retrun ret;
+		}
+	}
+
+	return 0;
+}
+
 static int _set_opp_custom(const struct opp_table *opp_table,
 			   struct device *dev, unsigned long old_freq,
 			   unsigned long freq,
@@ -837,12 +865,17 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
 		if (!_get_opp_count(opp_table))
 			return 0;
 
-		if (!opp_table->required_opp_tables && !opp_table->regulators) {
+		if (!opp_table->required_opp_tables && !opp_table->regulators &&
+		    !opp_table->paths) {
 			dev_err(dev, "target frequency can't be 0\n");
 			ret = -EINVAL;
 			goto put_opp_table;
 		}
 
+		ret = _set_opp_bw(opp_table, opp, true);
+		if (ret)
+			return ret;
+
 		if (opp_table->regulator_enabled) {
 			regulator_disable(opp_table->regulators[0]);
 			opp_table->regulator_enabled = false;
@@ -932,16 +965,8 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
 			dev_err(dev, "Failed to set required opps: %d\n", ret);
 	}
 
-	if (!ret && opp_table->paths) {
-		for (i = 0; i < opp_table->path_count; i++) {
-			ret = icc_set_bw(opp_table->paths[i],
-					 opp->bandwidth[i].avg,
-					 opp->bandwidth[i].peak);
-			if (ret)
-				dev_err(dev, "Failed to set bandwidth[%d]: %d\n",
-					i, ret);
-		}
-	}
+	if (!ret)
+		ret = _set_opp_bw(opp_table, opp, false);
 
 put_opp:
 	dev_pm_opp_put(opp);