opp: Add support for parsing interconnect bandwidth

The OPP bindings now support bandwidth values, so add support to parse it
from device tree and store it into the new dev_pm_opp_icc_bw struct, which
is part of the dev_pm_opp.

Signed-off-by: Georgi Djakov <[email protected]>
Reviewed-by: Matthias Kaehlcke <[email protected]>
[ Viresh: Create _read_bw() and use it, renamed _of_find_icc_paths() to
	  dev_pm_opp_of_find_icc_paths(), exported it and made opp_table
	  argument optional. Also drop the depends on from Kconfig. ]
Signed-off-by: Viresh Kumar <[email protected]>

Author: Georgi Djakov

drivers/opp/core.c

@@ -999,6 +999,12 @@ static struct opp_table *_allocate_opp_table(struct device *dev, int index)
 				ret);
 	}
 
+	/* Find interconnect path(s) for the device */
+	ret = dev_pm_opp_of_find_icc_paths(dev, opp_table);
+	if (ret)
+		dev_warn(dev, "%s: Error finding interconnect paths: %d\n",
+			 __func__, ret);
+
 	BLOCKING_INIT_NOTIFIER_HEAD(&opp_table->head);
 	INIT_LIST_HEAD(&opp_table->opp_list);
 	kref_init(&opp_table->kref);
@@ -1057,13 +1063,20 @@ static void _opp_table_kref_release(struct kref *kref)
 {
 	struct opp_table *opp_table = container_of(kref, struct opp_table, kref);
 	struct opp_device *opp_dev, *temp;
+	int i;
 
 	_of_clear_opp_table(opp_table);
 
 	/* Release clk */
 	if (!IS_ERR(opp_table->clk))
 		clk_put(opp_table->clk);
 
+	if (opp_table->paths) {
+		for (i = 0; i < opp_table->path_count; i++)
+			icc_put(opp_table->paths[i]);
+		kfree(opp_table->paths);
+	}
+
 	WARN_ON(!list_empty(&opp_table->opp_list));
 
 	list_for_each_entry_safe(opp_dev, temp, &opp_table->dev_list, node) {
@@ -1243,19 +1256,23 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_remove_all_dynamic);
 struct dev_pm_opp *_opp_allocate(struct opp_table *table)
 {
 	struct dev_pm_opp *opp;
-	int count, supply_size;
+	int supply_count, supply_size, icc_size;
 
 	/* Allocate space for at least one supply */
-	count = table->regulator_count > 0 ? table->regulator_count : 1;
-	supply_size = sizeof(*opp->supplies) * count;
+	supply_count = table->regulator_count > 0 ? table->regulator_count : 1;
+	supply_size = sizeof(*opp->supplies) * supply_count;
+	icc_size = sizeof(*opp->bandwidth) * table->path_count;
 
 	/* allocate new OPP node and supplies structures */
-	opp = kzalloc(sizeof(*opp) + supply_size, GFP_KERNEL);
+	opp = kzalloc(sizeof(*opp) + supply_size + icc_size, GFP_KERNEL);
+
 	if (!opp)
 		return NULL;
 
 	/* Put the supplies at the end of the OPP structure as an empty array */
 	opp->supplies = (struct dev_pm_opp_supply *)(opp + 1);
+	if (icc_size)
+		opp->bandwidth = (struct dev_pm_opp_icc_bw *)(opp->supplies + supply_count);
 	INIT_LIST_HEAD(&opp->node);
 
 	return opp;
@@ -1290,6 +1307,9 @@ int _opp_compare_key(struct dev_pm_opp *opp1, struct dev_pm_opp *opp2)
 {
 	if (opp1->rate != opp2->rate)
 		return opp1->rate < opp2->rate ? -1 : 1;
+	if (opp1->bandwidth && opp2->bandwidth &&
+	    opp1->bandwidth[0].peak != opp2->bandwidth[0].peak)
+		return opp1->bandwidth[0].peak < opp2->bandwidth[0].peak ? -1 : 1;
 	if (opp1->level != opp2->level)
 		return opp1->level < opp2->level ? -1 : 1;
 	return 0;

drivers/opp/of.c

@@ -332,6 +332,62 @@ static int _of_opp_alloc_required_opps(struct opp_table *opp_table,
 	return ret;
 }
 
+int dev_pm_opp_of_find_icc_paths(struct device *dev,
+				 struct opp_table *opp_table)
+{
+	struct device_node *np;
+	int ret = 0, i, count, num_paths;
+	struct icc_path **paths;
+
+	np = of_node_get(dev->of_node);
+	if (!np)
+		return 0;
+
+	count = of_count_phandle_with_args(np, "interconnects",
+					   "#interconnect-cells");
+	of_node_put(np);
+	if (count < 0)
+		return 0;
+
+	/* two phandles when #interconnect-cells = <1> */
+	if (count % 2) {
+		dev_err(dev, "%s: Invalid interconnects values\n", __func__);
+		return -EINVAL;
+	}
+
+	num_paths = count / 2;
+	paths = kcalloc(num_paths, sizeof(*paths), GFP_KERNEL);
+	if (!paths)
+		return -ENOMEM;
+
+	for (i = 0; i < num_paths; i++) {
+		paths[i] = of_icc_get_by_index(dev, i);
+		if (IS_ERR(paths[i])) {
+			ret = PTR_ERR(paths[i]);
+			if (ret != -EPROBE_DEFER) {
+				dev_err(dev, "%s: Unable to get path%d: %d\n",
+					__func__, i, ret);
+			}
+			goto err;
+		}
+	}
+
+	if (opp_table) {
+		opp_table->paths = paths;
+		opp_table->path_count = num_paths;
+		return 0;
+	}
+
+err:
+	while (i--)
+		icc_put(paths[i]);
+
+	kfree(paths);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_of_find_icc_paths);
+
 static bool _opp_is_supported(struct device *dev, struct opp_table *opp_table,
 			      struct device_node *np)
 {
@@ -521,9 +577,45 @@ void dev_pm_opp_of_remove_table(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_of_remove_table);
 
+static int _read_bw(struct dev_pm_opp *new_opp, struct device_node *np,
+		    bool peak)
+{
+	const char *name = peak ? "opp-peak-kBps" : "opp-avg-kBps";
+	struct property *prop;
+	int i, count, ret;
+	u32 *bw;
+
+	prop = of_find_property(np, name, NULL);
+	if (!prop)
+		return -ENODEV;
+
+	count = prop->length / sizeof(u32);
+	bw = kmalloc_array(count, sizeof(*bw), GFP_KERNEL);
+	if (!bw)
+		return -ENOMEM;
+
+	ret = of_property_read_u32_array(np, name, bw, count);
+	if (ret) {
+		pr_err("%s: Error parsing %s: %d\n", __func__, name, ret);
+		goto out;
+	}
+
+	for (i = 0; i < count; i++) {
+		if (peak)
+			new_opp->bandwidth[i].peak = kBps_to_icc(bw[i]);
+		else
+			new_opp->bandwidth[i].avg = kBps_to_icc(bw[i]);
+	}
+
+out:
+	kfree(bw);
+	return ret;
+}
+
 static int _read_opp_key(struct dev_pm_opp *new_opp, struct device_node *np,
 			 bool *rate_not_available)
 {
+	bool found = false;
 	u64 rate;
 	int ret;
 
@@ -535,10 +627,30 @@ static int _read_opp_key(struct dev_pm_opp *new_opp, struct device_node *np,
 		 * bit guaranteed in clk API.
 		 */
 		new_opp->rate = (unsigned long)rate;
+		found = true;
 	}
 	*rate_not_available = !!ret;
 
-	of_property_read_u32(np, "opp-level", &new_opp->level);
+	/*
+	 * Bandwidth consists of peak and average (optional) values:
+	 * opp-peak-kBps = <path1_value path2_value>;
+	 * opp-avg-kBps = <path1_value path2_value>;
+	 */
+	ret = _read_bw(new_opp, np, true);
+	if (!ret) {
+		found = true;
+		ret = _read_bw(new_opp, np, false);
+	}
+
+	/* The properties were found but we failed to parse them */
+	if (ret && ret != -ENODEV)
+		return ret;
+
+	if (!of_property_read_u32(np, "opp-level", &new_opp->level))
+		found = true;
+
+	if (found)
+		return 0;
 
 	return ret;
 }

drivers/opp/opp.h

@@ -12,6 +12,7 @@
 #define __DRIVER_OPP_H__
 
 #include <linux/device.h>
+#include <linux/interconnect.h>
 #include <linux/kernel.h>
 #include <linux/kref.h>
 #include <linux/list.h>
@@ -59,6 +60,7 @@ extern struct list_head opp_tables;
  * @rate:	Frequency in hertz
  * @level:	Performance level
  * @supplies:	Power supplies voltage/current values
+ * @bandwidth:	Interconnect bandwidth values
  * @clock_latency_ns: Latency (in nanoseconds) of switching to this OPP's
  *		frequency from any other OPP's frequency.
  * @required_opps: List of OPPs that are required by this OPP.
@@ -81,6 +83,7 @@ struct dev_pm_opp {
 	unsigned int level;
 
 	struct dev_pm_opp_supply *supplies;
+	struct dev_pm_opp_icc_bw *bandwidth;
 
 	unsigned long clock_latency_ns;
 
@@ -146,6 +149,8 @@ enum opp_table_access {
  * @regulator_count: Number of power supply regulators. Its value can be -1
  * (uninitialized), 0 (no opp-microvolt property) or > 0 (has opp-microvolt
  * property).
+ * @paths: Interconnect path handles
+ * @path_count: Number of interconnect paths
  * @genpd_performance_state: Device's power domain support performance state.
  * @is_genpd: Marks if the OPP table belongs to a genpd.
  * @set_opp: Platform specific set_opp callback
@@ -189,6 +194,8 @@ struct opp_table {
 	struct clk *clk;
 	struct regulator **regulators;
 	int regulator_count;
+	struct icc_path **paths;
+	unsigned int path_count;
 	bool genpd_performance_state;
 	bool is_genpd;
 

include/linux/pm_opp.h

@@ -41,6 +41,18 @@ struct dev_pm_opp_supply {
 	unsigned long u_amp;
 };
 
+/**
+ * struct dev_pm_opp_icc_bw - Interconnect bandwidth values
+ * @avg:	Average bandwidth corresponding to this OPP (in icc units)
+ * @peak:	Peak bandwidth corresponding to this OPP (in icc units)
+ *
+ * This structure stores the bandwidth values for a single interconnect path.
+ */
+struct dev_pm_opp_icc_bw {
+	u32 avg;
+	u32 peak;
+};
+
 /**
  * struct dev_pm_opp_info - OPP freq/voltage/current values
  * @rate:	Target clk rate in hz
@@ -360,6 +372,7 @@ int dev_pm_opp_of_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpuma
 struct device_node *dev_pm_opp_of_get_opp_desc_node(struct device *dev);
 struct device_node *dev_pm_opp_get_of_node(struct dev_pm_opp *opp);
 int of_get_required_opp_performance_state(struct device_node *np, int index);
+int dev_pm_opp_of_find_icc_paths(struct device *dev, struct opp_table *opp_table);
 void dev_pm_opp_of_register_em(struct cpumask *cpus);
 #else
 static inline int dev_pm_opp_of_add_table(struct device *dev)
@@ -408,6 +421,11 @@ static inline int of_get_required_opp_performance_state(struct device_node *np,
 {
 	return -ENOTSUPP;
 }
+
+static inline int dev_pm_opp_of_find_icc_paths(struct device *dev, struct opp_table *opp_table)
+{
+	return -ENOTSUPP;
+}
 #endif
 
 #endif		/* __LINUX_OPP_H__ */