linux-kernel - [PATCH v3 2/6] OPP: Add support for bandwidth OPP tables

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Date:   Tue,  2 Jul 2019 18:10:16 -0700
From:   Saravana Kannan <saravanak@...gle.com>
To:     Georgi Djakov <georgi.djakov@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Viresh Kumar <vireshk@...nel.org>, Nishanth Menon <nm@...com>,
        Stephen Boyd <sboyd@...nel.org>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>
Cc:     Saravana Kannan <saravanak@...gle.com>, vincent.guittot@...aro.org,
        seansw@....qualcomm.com, daidavid1@...eaurora.org,
        Rajendra Nayak <rnayak@...eaurora.org>, sibis@...eaurora.org,
        bjorn.andersson@...aro.org, evgreen@...omium.org,
        kernel-team@...roid.com, linux-pm@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v3 2/6] OPP: Add support for bandwidth OPP tables

Not all devices quantify their performance points in terms of frequency.
Devices like interconnects quantify their performance points in terms of
bandwidth. We need a way to represent these bandwidth levels in OPP. So,
add support for parsing bandwidth OPPs from DT.

Signed-off-by: Saravana Kannan <saravanak@...gle.com>
---
 drivers/opp/of.c  | 34 ++++++++++++++++++++++++++++++++--
 drivers/opp/opp.h |  4 +++-
 2 files changed, 35 insertions(+), 3 deletions(-)

diff --git a/drivers/opp/of.c b/drivers/opp/of.c
index c10c782d15aa..54fa70ed2adc 100644
--- a/drivers/opp/of.c
+++ b/drivers/opp/of.c
@@ -552,6 +552,35 @@ void dev_pm_opp_of_remove_table(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_of_remove_table);
 
+static int _read_opp_key(struct dev_pm_opp *new_opp, struct device_node *np)
+{
+	int ret;
+	u64 rate;
+	u32 bw;
+
+	ret = of_property_read_u64(np, "opp-hz", &rate);
+	if (!ret) {
+		/*
+		 * Rate is defined as an unsigned long in clk API, and so
+		 * casting explicitly to its type. Must be fixed once rate is 64
+		 * bit guaranteed in clk API.
+		 */
+		new_opp->rate = (unsigned long)rate;
+		return 0;
+	}
+
+	ret = of_property_read_u32(np, "opp-peak-KBps", &bw);
+	if (ret)
+		return ret;
+	new_opp->rate = (unsigned long) &bw;
+
+	ret = of_property_read_u32(np, "opp-avg-KBps", &bw);
+	if (!ret)
+		new_opp->avg_bw = (unsigned long) &bw;
+
+	return 0;
+}
+
 /**
  * _opp_add_static_v2() - Allocate static OPPs (As per 'v2' DT bindings)
  * @opp_table:	OPP table
@@ -589,11 +618,12 @@ static struct dev_pm_opp *_opp_add_static_v2(struct opp_table *opp_table,
 	if (!new_opp)
 		return ERR_PTR(-ENOMEM);
 
-	ret = of_property_read_u64(np, "opp-hz", &rate);
+	ret = _read_opp_key(new_opp, np);
 	if (ret < 0) {
 		/* "opp-hz" is optional for devices like power domains. */
 		if (!opp_table->is_genpd) {
-			dev_err(dev, "%s: opp-hz not found\n", __func__);
+			dev_err(dev, "%s: opp-hz or opp-peak-bw not found\n",
+				__func__);
 			goto free_opp;
 		}
 
diff --git a/drivers/opp/opp.h b/drivers/opp/opp.h
index 569b3525aa67..ead2cdafe957 100644
--- a/drivers/opp/opp.h
+++ b/drivers/opp/opp.h
@@ -59,7 +59,8 @@ extern struct list_head opp_tables;
  * @turbo:	true if turbo (boost) OPP
  * @suspend:	true if suspend OPP
  * @pstate: Device's power domain's performance state.
- * @rate:	Frequency in hertz
+ * @rate:	Frequency in hertz OR Peak bandwidth in kilobytes per second
+ * @avg_bw:	Average bandwidth in kilobytes per second
  * @level:	Performance level
  * @supplies:	Power supplies voltage/current values
  * @clock_latency_ns: Latency (in nanoseconds) of switching to this OPP's
@@ -81,6 +82,7 @@ struct dev_pm_opp {
 	bool suspend;
 	unsigned int pstate;
 	unsigned long rate;
+	unsigned long avg_bw;
 	unsigned int level;
 
 	struct dev_pm_opp_supply *supplies;
-- 
2.22.0.410.gd8fdbe21b5-goog