linux-kernel - [PATCH RFC 1/8] opp: core: implement dev_pm_opp_get

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Message-Id: <20241113-topic-sm8x50-gpu-bw-vote-v1-1-3b8d39737a9b@linaro.org>
Date: Wed, 13 Nov 2024 16:48:27 +0100
From: Neil Armstrong <neil.armstrong@...aro.org>
To: Akhil P Oommen <quic_akhilpo@...cinc.com>, 
 Viresh Kumar <vireshk@...nel.org>, Nishanth Menon <nm@...com>, 
 Stephen Boyd <sboyd@...nel.org>, "Rafael J. Wysocki" <rafael@...nel.org>, 
 Rob Clark <robdclark@...il.com>, Sean Paul <sean@...rly.run>, 
 Konrad Dybcio <konradybcio@...nel.org>, 
 Abhinav Kumar <quic_abhinavk@...cinc.com>, 
 Dmitry Baryshkov <dmitry.baryshkov@...aro.org>, 
 Marijn Suijten <marijn.suijten@...ainline.org>, 
 David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>, 
 Bjorn Andersson <andersson@...nel.org>, Rob Herring <robh@...nel.org>, 
 Krzysztof Kozlowski <krzk+dt@...nel.org>, 
 Conor Dooley <conor+dt@...nel.org>
Cc: Connor Abbott <cwabbott0@...il.com>, linux-pm@...r.kernel.org, 
 linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org, 
 dri-devel@...ts.freedesktop.org, freedreno@...ts.freedesktop.org, 
 devicetree@...r.kernel.org, Neil Armstrong <neil.armstrong@...aro.org>
Subject: [PATCH RFC 1/8] opp: core: implement dev_pm_opp_get_bandwidth

Add and implement the dev_pm_opp_get_bandwidth() to retrieve
the OPP's bandwidth in the same was as the dev_pm_opp_get_voltage()
helper.

Retrieving bandwidth is required in the case of the Adreno GPU
where the GPU Management Unit can handle the Bandwidth scaling.

The helper can get the peak or everage bandwidth for any of
the interconnect path.

Signed-off-by: Neil Armstrong <neil.armstrong@...aro.org>
---
 drivers/opp/core.c     | 25 +++++++++++++++++++++++++
 include/linux/pm_opp.h |  7 +++++++
 2 files changed, 32 insertions(+)

diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index 494f8860220d97fc690ebab5ed3b7f5f04f22d73..19fb82033de26b74e9604c33b9781689df2fe80a 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -106,6 +106,31 @@ static bool assert_single_clk(struct opp_table *opp_table)
 	return !WARN_ON(opp_table->clk_count > 1);
 }

+/**
+ * dev_pm_opp_get_bandwidth() - Gets the peak bandwidth corresponding to an opp
+ * @opp:	opp for which voltage has to be returned for
+ * @peak:	select peak or average bandwidth
+ * @index:	bandwidth index
+ *
+ * Return: peak bandwidth in kBps, else return 0
+ */
+unsigned long dev_pm_opp_get_bandwidth(struct dev_pm_opp *opp, bool peak, int index)
+{
+	if (IS_ERR_OR_NULL(opp)) {
+		pr_err("%s: Invalid parameters\n", __func__);
+		return 0;
+	}
+
+	if (index > opp->opp_table->path_count)
+		return 0;
+
+	if (!opp->bandwidth)
+		return 0;
+
+	return peak ? opp->bandwidth[index].peak : opp->bandwidth[index].avg;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_get_bandwidth);
+
 /**
  * dev_pm_opp_get_voltage() - Gets the voltage corresponding to an opp
  * @opp:	opp for which voltage has to be returned for
diff --git a/include/linux/pm_opp.h b/include/linux/pm_opp.h
index 6424692c30b71fca471a1b7d63e018605dd9324b..526b707a8d61204227222f8c28394dc3a85c4c9a 100644
--- a/include/linux/pm_opp.h
+++ b/include/linux/pm_opp.h
@@ -106,6 +106,8 @@ struct dev_pm_opp_data {
 struct opp_table *dev_pm_opp_get_opp_table(struct device *dev);
 void dev_pm_opp_put_opp_table(struct opp_table *opp_table);

+unsigned long dev_pm_opp_get_bandwidth(struct dev_pm_opp *opp, bool peak, int index);
+
 unsigned long dev_pm_opp_get_voltage(struct dev_pm_opp *opp);

 int dev_pm_opp_get_supplies(struct dev_pm_opp *opp, struct dev_pm_opp_supply *supplies);
@@ -209,6 +211,11 @@ static inline struct opp_table *dev_pm_opp_get_opp_table_indexed(struct device *

 static inline void dev_pm_opp_put_opp_table(struct opp_table *opp_table) {}

+static inline unsigned long dev_pm_opp_get_bandwidth(struct dev_pm_opp *opp, bool peak, int index)
+{
+	return 0;
+}
+
 static inline unsigned long dev_pm_opp_get_voltage(struct dev_pm_opp *opp)
 {
 	return 0;

-- 
2.34.1