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 <georgi.djakov@linaro.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
[ 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 <viresh.kumar@linaro.org>

drivers/opp/of.c

@@ -332,6 +332,62 @@ free_required_opps:
 	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;
 }