Message-Id: <20220411154347.491396-5-krzysztof.kozlowski@linaro.org>
Date:   Mon, 11 Apr 2022 17:43:45 +0200
From:   Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To:     Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Viresh Kumar <vireshk@...nel.org>, Nishanth Menon <nm@...com>,
        Alim Akhtar <alim.akhtar@...sung.com>,
        Avri Altman <avri.altman@....com>,
        "James E.J. Bottomley" <jejb@...ux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@...cle.com>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Taniya Das <tdas@...eaurora.org>,
        linux-arm-msm@...r.kernel.org, linux-clk@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-pm@...r.kernel.org, linux-scsi@...r.kernel.org
Cc:     Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
Subject: [RFC PATCH v2 4/6] PM: opp: allow control of multiple clocks

Devices might need to control several clocks when scaling the frequency
and voltage.  Example is the Universal Flash Storage (UFS) which scales
several independent clocks with change of performance levels.

Add parsing of multiple clocks and clock names and scale all of them,
when needed.  If only one clock is provided, the code should behave the
same as before.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
---
 drivers/opp/core.c     | 205 ++++++++++++++++++++++++++++++++---------
 drivers/opp/of.c       |  48 ++++++++++
 drivers/opp/opp.h      |   9 +-
 include/linux/pm_opp.h |  23 +++++
 4 files changed, 242 insertions(+), 43 deletions(-)

diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index 2945f3c1ce09..5dcd7157f6ab 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -66,6 +66,21 @@ static struct opp_table *_find_opp_table_unlocked(struct device *dev)
 	return ERR_PTR(-ENODEV);
 }
 
+static void _put_clocks(struct opp_table *opp_table)
+{
+	int i;
+
+	if (!opp_table->clks)
+		return;
+
+	for (i = opp_table->clk_count - 1; i >= 0; i--)
+		clk_put(opp_table->clks[i]);
+
+	kfree(opp_table->clks);
+	opp_table->clks = NULL;
+	opp_table->clk_count = -1;
+};
+
 /**
  * _find_opp_table() - find opp_table struct using device pointer
  * @dev:	device pointer used to lookup OPP table
@@ -772,6 +787,30 @@ static inline int _generic_set_opp_clk_only(struct device *dev, struct clk *clk,
 	return ret;
 }
 
+static int _generic_set_opp_clks_only(struct device *dev,
+				      struct opp_table *opp_table,
+				      struct dev_pm_opp *opp)
+{
+	int i, ret;
+
+	if (!opp_table->clks)
+		return 0;
+
+	for (i = 0; i < opp_table->clk_count; i++) {
+		if (opp->rates[i]) {
+			ret = _generic_set_opp_clk_only(dev, opp_table->clks[i],
+							opp->rates[i]);
+			if (ret) {
+				dev_err(dev, "%s: failed to set clock %pC rate: %d\n",
+					__func__, opp_table->clks[i], ret);
+				return ret;
+			}
+		}
+	}
+
+	return 0;
+}
+
 static int _generic_set_opp_regulator(struct opp_table *opp_table,
 				      struct device *dev,
 				      struct dev_pm_opp *opp,
@@ -796,7 +835,7 @@ static int _generic_set_opp_regulator(struct opp_table *opp_table,
 	}
 
 	/* Change frequency */
-	ret = _generic_set_opp_clk_only(dev, opp_table->clk, freq);
+	ret = _generic_set_opp_clks_only(dev, opp_table, opp);
 	if (ret)
 		goto restore_voltage;
 
@@ -820,7 +859,7 @@ static int _generic_set_opp_regulator(struct opp_table *opp_table,
 	return 0;
 
 restore_freq:
-	if (_generic_set_opp_clk_only(dev, opp_table->clk, old_opp->rate))
+	if (_generic_set_opp_clks_only(dev, opp_table, old_opp))
 		dev_err(dev, "%s: failed to restore old-freq (%lu Hz)\n",
 			__func__, old_opp->rate);
 restore_voltage:
@@ -880,7 +919,7 @@ static int _set_opp_custom(const struct opp_table *opp_table,
 	}
 
 	data->regulators = opp_table->regulators;
-	data->clk = opp_table->clk;
+	data->clk = (opp_table->clks ? opp_table->clks[0] : NULL);
 	data->dev = dev;
 	data->old_opp.rate = old_opp->rate;
 	data->new_opp.rate = freq;
@@ -969,8 +1008,8 @@ static void _find_current_opp(struct device *dev, struct opp_table *opp_table)
 	struct dev_pm_opp *opp = ERR_PTR(-ENODEV);
 	unsigned long freq;
 
-	if (!IS_ERR(opp_table->clk)) {
-		freq = clk_get_rate(opp_table->clk);
+	if (opp_table->clks && !IS_ERR(opp_table->clks[0])) {
+		freq = clk_get_rate(opp_table->clks[0]);
 		opp = _find_freq_ceil(opp_table, &freq);
 	}
 
@@ -1070,7 +1109,7 @@ static int _set_opp(struct device *dev, struct opp_table *opp_table,
 						 scaling_down);
 	} else {
 		/* Only frequency scaling */
-		ret = _generic_set_opp_clk_only(dev, opp_table->clk, freq);
+		ret = _generic_set_opp_clks_only(dev, opp_table, opp);
 	}
 
 	if (ret)
@@ -1135,11 +1174,15 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
 		 * equivalent to a clk_set_rate()
 		 */
 		if (!_get_opp_count(opp_table)) {
-			ret = _generic_set_opp_clk_only(dev, opp_table->clk, target_freq);
+			if (opp_table->clks)
+				ret = _generic_set_opp_clk_only(dev,
+								opp_table->clks[0],
+								target_freq);
 			goto put_opp_table;
 		}
 
-		freq = clk_round_rate(opp_table->clk, target_freq);
+		if (opp_table->clks)
+			freq = clk_round_rate(opp_table->clks[0], target_freq);
 		if ((long)freq <= 0)
 			freq = target_freq;
 
@@ -1156,6 +1199,11 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
 				__func__, freq, ret);
 			goto put_opp_table;
 		}
+		/*
+		 * opp->rates are used for scaling clocks, so be sure accurate
+		 * 'freq' is used, instead what was defined via e.g. Devicetree.
+		 */
+		opp->rates[0] = freq;
 	}
 
 	ret = _set_opp(dev, opp_table, opp, freq);
@@ -1246,7 +1294,8 @@ static struct opp_table *_allocate_opp_table(struct device *dev, int index)
 	INIT_LIST_HEAD(&opp_table->dev_list);
 	INIT_LIST_HEAD(&opp_table->lazy);
 
-	/* Mark regulator count uninitialized */
+	/* Mark regulator/clk count uninitialized */
+	opp_table->clk_count = -1;
 	opp_table->regulator_count = -1;
 
 	opp_dev = _add_opp_dev(dev, opp_table);
@@ -1295,21 +1344,32 @@ static struct opp_table *_update_opp_table_clk(struct device *dev,
 	 * Return early if we don't need to get clk or we have already tried it
 	 * earlier.
 	 */
-	if (!getclk || IS_ERR(opp_table) || opp_table->clk)
+	if (!getclk || IS_ERR(opp_table) || opp_table->clks)
 		return opp_table;
 
+	opp_table->clks = kmalloc_array(1, sizeof(*opp_table->clks),
+					GFP_KERNEL);
+	if (!opp_table->clks)
+		return ERR_PTR(-ENOMEM);
+
 	/* Find clk for the device */
-	opp_table->clk = clk_get(dev, NULL);
+	opp_table->clks[0] = clk_get(dev, NULL);
 
-	ret = PTR_ERR_OR_ZERO(opp_table->clk);
-	if (!ret)
+	ret = PTR_ERR_OR_ZERO(opp_table->clks[0]);
+	if (!ret) {
+		opp_table->clk_count = 1;
 		return opp_table;
+	}
 
 	if (ret == -ENOENT) {
+		opp_table->clk_count = 0;
 		dev_dbg(dev, "%s: Couldn't find clock: %d\n", __func__, ret);
 		return opp_table;
 	}
 
+	kfree(opp_table->clks);
+	opp_table->clks = NULL;
+	opp_table->clk_count = -1;
 	dev_pm_opp_put_opp_table(opp_table);
 	dev_err_probe(dev, ret, "Couldn't find clock\n");
 
@@ -1408,9 +1468,7 @@ static void _opp_table_kref_release(struct kref *kref)
 
 	_of_clear_opp_table(opp_table);
 
-	/* Release clk */
-	if (!IS_ERR(opp_table->clk))
-		clk_put(opp_table->clk);
+	_put_clocks(opp_table);
 
 	if (opp_table->paths) {
 		for (i = 0; i < opp_table->path_count; i++)
@@ -2144,9 +2202,51 @@ EXPORT_SYMBOL_GPL(devm_pm_opp_set_regulators);
  * This must be called before any OPPs are initialized for the device.
  */
 struct opp_table *dev_pm_opp_set_clkname(struct device *dev, const char *name)
+{
+	return dev_pm_opp_set_clknames(dev, &name, 1);
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_set_clkname);
+
+/**
+ * dev_pm_opp_put_clkname() - Releases resources blocked for clk.
+ * @opp_table: OPP table returned from dev_pm_opp_set_clkname().
+ */
+void dev_pm_opp_put_clkname(struct opp_table *opp_table)
+{
+	return dev_pm_opp_put_clknames(opp_table);
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_put_clkname);
+
+/**
+ * devm_pm_opp_set_clkname() - Set clk name for the device
+ * @dev: Device for which clk name is being set.
+ * @name: Clk name.
+ *
+ * This is a resource-managed variant of dev_pm_opp_set_clkname().
+ *
+ * Return: 0 on success and errorno otherwise.
+ */
+int devm_pm_opp_set_clkname(struct device *dev, const char *name)
+{
+	return devm_pm_opp_set_clknames(dev, &name, 1);
+}
+EXPORT_SYMBOL_GPL(devm_pm_opp_set_clkname);
+
+/**
+ * dev_pm_opp_set_clknames() - Set clk names for the device
+ * @dev: Device for which clock names are being set.
+ * @names: Array of pointers to the names of the clocks.
+ * @count: Number of clocks.
+ *
+ * See: dev_pm_opp_set_clkname()
+ */
+struct opp_table *dev_pm_opp_set_clknames(struct device *dev,
+					  const char * const names[],
+					  unsigned int count)
 {
 	struct opp_table *opp_table;
-	int ret;
+	struct clk *clk;
+	int ret, i;
 
 	opp_table = _add_opp_table(dev, false);
 	if (IS_ERR(opp_table))
@@ -2159,70 +2259,92 @@ struct opp_table *dev_pm_opp_set_clkname(struct device *dev, const char *name)
 	}
 
 	/* clk shouldn't be initialized at this point */
-	if (WARN_ON(opp_table->clk)) {
+	if (WARN_ON(opp_table->clks)) {
 		ret = -EBUSY;
 		goto err;
 	}
 
-	/* Find clk for the device */
-	opp_table->clk = clk_get(dev, name);
-	if (IS_ERR(opp_table->clk)) {
-		ret = dev_err_probe(dev, PTR_ERR(opp_table->clk),
-				    "%s: Couldn't find clock\n", __func__);
+	opp_table->clks = kmalloc_array(count, sizeof(*opp_table->clks),
+					GFP_KERNEL);
+	if (!opp_table->clks) {
+		ret = -ENOMEM;
 		goto err;
 	}
 
+	for (i = 0; i < count; i++) {
+		clk = clk_get(dev, names[i]);
+		if (IS_ERR(clk)) {
+			ret =  dev_err_probe(dev, PTR_ERR(clk),
+					     "%s: Couldn't find clock %s\n",
+					     __func__, names[i]);
+			goto free_clks;
+		}
+
+		opp_table->clks[i] = clk;
+	}
+
+	opp_table->clk_count = count;
+
 	return opp_table;
 
+free_clks:
+	while (i != 0)
+		clk_put(opp_table->clks[--i]);
+
+	kfree(opp_table->clks);
+	opp_table->clks = NULL;
+	opp_table->clk_count = -1;
 err:
 	dev_pm_opp_put_opp_table(opp_table);
 
 	return ERR_PTR(ret);
 }
-EXPORT_SYMBOL_GPL(dev_pm_opp_set_clkname);
+EXPORT_SYMBOL_GPL(dev_pm_opp_set_clknames);
 
 /**
- * dev_pm_opp_put_clkname() - Releases resources blocked for clk.
- * @opp_table: OPP table returned from dev_pm_opp_set_clkname().
+ * dev_pm_opp_put_clknames() - Releases resources blocked for clk.
+ * @opp_table: OPP table returned from dev_pm_opp_set_clknames().
  */
-void dev_pm_opp_put_clkname(struct opp_table *opp_table)
+void dev_pm_opp_put_clknames(struct opp_table *opp_table)
 {
 	if (unlikely(!opp_table))
 		return;
 
-	clk_put(opp_table->clk);
-	opp_table->clk = ERR_PTR(-EINVAL);
+	_put_clocks(opp_table);
 
 	dev_pm_opp_put_opp_table(opp_table);
 }
-EXPORT_SYMBOL_GPL(dev_pm_opp_put_clkname);
+EXPORT_SYMBOL_GPL(dev_pm_opp_put_clknames);
 
-static void devm_pm_opp_clkname_release(void *data)
+static void devm_pm_opp_clknames_release(void *data)
 {
-	dev_pm_opp_put_clkname(data);
+	dev_pm_opp_put_clknames(data);
 }
 
 /**
- * devm_pm_opp_set_clkname() - Set clk name for the device
- * @dev: Device for which clk name is being set.
- * @name: Clk name.
+ * devm_pm_opp_set_clknames() - Set clock names for the device
+ * @dev: Device for which clock names are being set.
+ * @names: Array of pointers to the names of the clocks.
+ * @count: Number of clocks.
  *
- * This is a resource-managed variant of dev_pm_opp_set_clkname().
+ * This is a resource-managed variant of dev_pm_opp_set_clknames().
  *
  * Return: 0 on success and errorno otherwise.
  */
-int devm_pm_opp_set_clkname(struct device *dev, const char *name)
+int devm_pm_opp_set_clknames(struct device *dev,
+			     const char * const names[],
+			     unsigned int count)
 {
 	struct opp_table *opp_table;
 
-	opp_table = dev_pm_opp_set_clkname(dev, name);
+	opp_table = dev_pm_opp_set_clknames(dev, names, count);
 	if (IS_ERR(opp_table))
 		return PTR_ERR(opp_table);
 
-	return devm_add_action_or_reset(dev, devm_pm_opp_clkname_release,
+	return devm_add_action_or_reset(dev, devm_pm_opp_clknames_release,
 					opp_table);
 }
-EXPORT_SYMBOL_GPL(devm_pm_opp_set_clkname);
+EXPORT_SYMBOL_GPL(devm_pm_opp_set_clknames);
 
 /**
  * dev_pm_opp_register_set_opp_helper() - Register custom set OPP helper
@@ -2637,7 +2759,8 @@ int dev_pm_opp_add(struct device *dev, unsigned long freq, unsigned long u_volt)
 	if (IS_ERR(opp_table))
 		return PTR_ERR(opp_table);
 
-	/* Fix regulator count for dynamic OPPs */
+	/* Fix regulator/clk count for dynamic OPPs */
+	opp_table->clk_count = 1;
 	opp_table->regulator_count = 1;
 
 	ret = _opp_add_v1(opp_table, dev, freq, u_volt, true);
diff --git a/drivers/opp/of.c b/drivers/opp/of.c
index 440ab5a03df9..26ab58b71c2d 100644
--- a/drivers/opp/of.c
+++ b/drivers/opp/of.c
@@ -767,6 +767,47 @@ void dev_pm_opp_of_remove_table(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_of_remove_table);
 
+static int _read_clocks(struct dev_pm_opp *opp, struct opp_table *opp_table,
+			struct device_node *np)
+{
+	int count, ret;
+	u64 *freq;
+
+	count = of_property_count_u64_elems(np, "opp-hz");
+	if (count < 0) {
+		pr_err("%s: Invalid %s property (%d)\n",
+			__func__, of_node_full_name(np), count);
+		return count;
+	}
+
+	if (count != opp_table->clk_count) {
+		pr_err("%s: number of rates %d does not match number of clocks %d in %s\n",
+		       __func__, count, opp_table->clk_count,
+		       of_node_full_name(np));
+		return -EINVAL;
+	}
+
+	freq = kmalloc_array(count, sizeof(*freq), GFP_KERNEL);
+	if (!freq)
+		return -ENOMEM;
+
+	ret = of_property_read_u64_array(np, "opp-hz", freq, count);
+	if (ret) {
+		pr_err("%s: error parsing %s: %d\n", __func__,
+		       of_node_full_name(np), ret);
+		ret = -EINVAL;
+		goto free_freq;
+	}
+
+	opp->rates = freq;
+	return 0;
+
+free_freq:
+	kfree(freq);
+
+	return ret;
+}
+
 static int _read_bw(struct dev_pm_opp *new_opp, struct opp_table *table,
 		    struct device_node *np, bool peak)
 {
@@ -827,6 +868,13 @@ static int _read_opp_key(struct dev_pm_opp *new_opp, struct opp_table *table,
 	}
 	*rate_not_available = !!ret;
 
+	if (!ret) {
+		ret = _read_clocks(new_opp, table, np);
+		/* The properties were found but we failed to parse them */
+		if (ret && ret != -ENODEV)
+			return ret;
+	}
+
 	/*
 	 * Bandwidth consists of peak and average (optional) values:
 	 * opp-peak-kBps = <path1_value path2_value>;
diff --git a/drivers/opp/opp.h b/drivers/opp/opp.h
index 45e3a55239a1..2c4502cff3b2 100644
--- a/drivers/opp/opp.h
+++ b/drivers/opp/opp.h
@@ -60,6 +60,7 @@ extern struct list_head opp_tables, lazy_opp_tables;
  * @pstate: Device's power domain's performance state.
  * @rate:	Frequency in hertz
  * @level:	Performance level
+ * @rates:	Frequency rates for the clocks.
  * @supplies:	Power supplies voltage/current values
  * @bandwidth:	Interconnect bandwidth values
  * @clock_latency_ns: Latency (in nanoseconds) of switching to this OPP's
@@ -84,6 +85,7 @@ struct dev_pm_opp {
 	unsigned long rate;
 	unsigned int level;
 
+	u64 *rates;
 	struct dev_pm_opp_supply *supplies;
 	struct dev_pm_opp_icc_bw *bandwidth;
 
@@ -149,7 +151,9 @@ enum opp_table_access {
  * @supported_hw: Array of version number to support.
  * @supported_hw_count: Number of elements in supported_hw array.
  * @prop_name: A name to postfix to many DT properties, while parsing them.
- * @clk: Device's clock handle
+ * @clks: Device clocks handles
+ * @clk_count: Number of clocks. Its value can be -1 (uninitialized), 0 (no
+ * clock handle provided)  or > 0 (has clock handles).
  * @regulators: Supply regulators
  * @regulator_count: Number of power supply regulators. Its value can be -1
  * (uninitialized), 0 (no opp-microvolt property) or > 0 (has opp-microvolt
@@ -200,7 +204,8 @@ struct opp_table {
 	unsigned int *supported_hw;
 	unsigned int supported_hw_count;
 	const char *prop_name;
-	struct clk *clk;
+	struct clk **clks;
+	int clk_count;
 	struct regulator **regulators;
 	int regulator_count;
 	struct icc_path **paths;
diff --git a/include/linux/pm_opp.h b/include/linux/pm_opp.h
index 0d85a63a1f78..cb50ccf6f818 100644
--- a/include/linux/pm_opp.h
+++ b/include/linux/pm_opp.h
@@ -158,6 +158,13 @@ int devm_pm_opp_set_regulators(struct device *dev, const char * const names[], u
 struct opp_table *dev_pm_opp_set_clkname(struct device *dev, const char *name);
 void dev_pm_opp_put_clkname(struct opp_table *opp_table);
 int devm_pm_opp_set_clkname(struct device *dev, const char *name);
+struct opp_table *dev_pm_opp_set_clknames(struct device *dev,
+					  const char * const names[],
+					  unsigned int count);
+void dev_pm_opp_put_clknames(struct opp_table *opp_table);
+int devm_pm_opp_set_clknames(struct device *dev,
+			     const char * const names[],
+			     unsigned int count);
 struct opp_table *dev_pm_opp_register_set_opp_helper(struct device *dev, int (*set_opp)(struct dev_pm_set_opp_data *data));
 void dev_pm_opp_unregister_set_opp_helper(struct opp_table *opp_table);
 int devm_pm_opp_register_set_opp_helper(struct device *dev, int (*set_opp)(struct dev_pm_set_opp_data *data));
@@ -386,6 +393,22 @@ static inline int devm_pm_opp_set_clkname(struct device *dev, const char *name)
 	return -EOPNOTSUPP;
 }
 
+static inline struct opp_table *dev_pm_opp_set_clknames(struct device *dev,
+							const char * const names[],
+							unsigned int count)
+{
+	return ERR_PTR(-EOPNOTSUPP);
+}
+
+static inline void dev_pm_opp_put_clknames(struct opp_table *opp_table) {}
+
+static inline int devm_pm_opp_set_clknames(struct device *dev,
+					   const char * const names[],
+					   unsigned int count)
+{
+	return -EOPNOTSUPP;
+}
+
 static inline struct opp_table *dev_pm_opp_attach_genpd(struct device *dev, const char * const *names, struct device ***virt_devs)
 {
 	return ERR_PTR(-EOPNOTSUPP);
-- 
2.32.0

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