[PATCH 2/4] OPP: Add support for parsing the interconnect bandwidth

[Georgi Djakov]

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.

Also add and export the dev_pm_opp_set_path() and dev_pm_opp_put_path()
helpers, to set (and release) an interconnect path to a device. The
bandwidth of this path will be updated when the OPPs are switched.

Signed-off-by: Georgi Djakov <georgi.djakov@xxxxxxxxxx>
---
 drivers/opp/core.c     | 67 ++++++++++++++++++++++++++++++++++++++++++
 drivers/opp/of.c       | 44 +++++++++++++++++++++++++++
 drivers/opp/opp.h      |  6 ++++
 include/linux/pm_opp.h | 14 +++++++++
 4 files changed, 131 insertions(+)

diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index e06a0ab05ad6..4b019cecaa07 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -19,6 +19,7 @@
 #include <linux/slab.h>
 #include <linux/device.h>
 #include <linux/export.h>
+#include <linux/interconnect.h>
 #include <linux/pm_domain.h>
 #include <linux/regulator/consumer.h>
 
@@ -1645,6 +1646,72 @@ void dev_pm_opp_put_clkname(struct opp_table *opp_table)
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_put_clkname);
 
+/**
+ * dev_pm_opp_set_path() - Set interconnect path for a device
+ * @dev: Device for which interconnect path is being set.
+ * @name: Interconnect path name or NULL.
+ *
+ * This must be called before any OPPs are initialized for the device.
+ */
+struct opp_table *dev_pm_opp_set_path(struct device *dev, const char *name)
+{
+	struct opp_table *opp_table;
+	int ret;
+
+	opp_table = dev_pm_opp_get_opp_table(dev);
+	if (!opp_table)
+		return ERR_PTR(-ENOMEM);
+
+	/* This should be called before OPPs are initialized */
+	if (WARN_ON(!list_empty(&opp_table->opp_list))) {
+		ret = -EBUSY;
+		goto err;
+	}
+
+	/* Another CPU that shares the OPP table has set the path */
+	if (opp_table->path)
+		return opp_table;
+
+	/* Find interconnect path for the device */
+	opp_table->path = of_icc_get(dev, name);
+	if (IS_ERR(opp_table->path)) {
+		ret = PTR_ERR(opp_table->clk);
+		if (ret != -EPROBE_DEFER) {
+			dev_err(dev, "%s: Couldn't find path: %d\n", __func__,
+				ret);
+		}
+		goto err;
+	}
+
+	return opp_table;
+
+err:
+	dev_pm_opp_put_opp_table(opp_table);
+
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_set_path);
+
+/**
+ * dev_pm_opp_put_path() - Release interconnect path resources
+ * @opp_table: OPP table returned from dev_pm_opp_set_path().
+ */
+void dev_pm_opp_put_path(struct opp_table *opp_table)
+{
+	if (!opp_table->path)
+		goto put_opp_table;
+
+	/* Make sure there are no concurrent readers while updating opp_table */
+	WARN_ON(!list_empty(&opp_table->opp_list));
+
+	icc_put(opp_table->path);
+	opp_table->path = NULL;
+
+put_opp_table:
+	dev_pm_opp_put_opp_table(opp_table);
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_put_path);
+
 /**
  * dev_pm_opp_register_set_opp_helper() - Register custom set OPP helper
  * @dev: Device for which the helper is getting registered.
diff --git a/drivers/opp/of.c b/drivers/opp/of.c
index 1779f2c93291..96fb7fdda8c7 100644
--- a/drivers/opp/of.c
+++ b/drivers/opp/of.c
@@ -16,6 +16,7 @@
 #include <linux/cpu.h>
 #include <linux/errno.h>
 #include <linux/device.h>
+#include <linux/interconnect.h>
 #include <linux/of_device.h>
 #include <linux/pm_domain.h>
 #include <linux/slab.h>
@@ -526,6 +527,45 @@ static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev,
 	return ret;
 }
 
+static int opp_parse_icc_bw(struct dev_pm_opp *opp, struct device *dev,
+			    struct opp_table *opp_table)
+{
+	struct property *prop = NULL;
+	char name[NAME_MAX];
+	int count;
+	u32 avg = 0;
+	u32 peak = 0;
+
+	/* Search for "opp-bw-MBs" */
+	sprintf(name, "opp-bw-MBs");
+	prop = of_find_property(opp->np, name, NULL);
+
+	/* Missing property is not a problem */
+	if (!prop) {
+		dev_dbg(dev, "%s: Missing opp-bw-MBs\n", __func__);
+		return 0;
+	}
+
+	count = of_property_count_u32_elems(opp->np, name);
+	if (count != 2) {
+		dev_err(dev, "%s: Invalid number of elements in %s property\n",
+			__func__, name);
+		return -EINVAL;
+	}
+
+	opp->bandwidth = kzalloc(sizeof(*opp->bandwidth), GFP_KERNEL);
+	if (!opp->bandwidth)
+		return -ENOMEM;
+
+	of_property_read_u32_index(opp->np, name, 0, &avg);
+	of_property_read_u32_index(opp->np, name, 1, &peak);
+
+	opp->bandwidth->avg = MBps_to_icc(avg);
+	opp->bandwidth->peak = MBps_to_icc(peak);
+
+	return 0;
+}
+
 /**
  * dev_pm_opp_of_remove_table() - Free OPP table entries created from static DT
  *				  entries
@@ -619,6 +659,10 @@ static struct dev_pm_opp *_opp_add_static_v2(struct opp_table *opp_table,
 	if (ret)
 		goto free_required_opps;
 
+	ret = opp_parse_icc_bw(new_opp, dev, opp_table);
+	if (ret)
+		goto free_required_opps;
+
 	if (opp_table->is_genpd)
 		new_opp->pstate = pm_genpd_opp_to_performance_state(dev, new_opp);
 
diff --git a/drivers/opp/opp.h b/drivers/opp/opp.h
index 4458175aa661..b4287d065c24 100644
--- a/drivers/opp/opp.h
+++ b/drivers/opp/opp.h
@@ -24,6 +24,7 @@
 
 struct clk;
 struct regulator;
+struct icc_path;
 
 /* Lock to allow exclusive modification to the device and opp lists */
 extern struct mutex opp_table_lock;
@@ -62,6 +63,7 @@ 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.
@@ -85,6 +87,8 @@ struct dev_pm_opp {
 
 	struct dev_pm_opp_supply *supplies;
 
+	struct dev_pm_opp_icc_bw *bandwidth;
+
 	unsigned long clock_latency_ns;
 
 	struct dev_pm_opp **required_opps;
@@ -152,6 +156,7 @@ enum opp_table_access {
  * property).
  * @genpd_performance_state: Device's power domain support performance state.
  * @is_genpd: Marks if the OPP table belongs to a genpd.
+ * @path: Interconnect path handle
  * @set_opp: Platform specific set_opp callback
  * @set_opp_data: Data to be passed to set_opp callback
  * @dentry:	debugfs dentry pointer of the real device directory (not links).
@@ -196,6 +201,7 @@ struct opp_table {
 	int regulator_count;
 	bool genpd_performance_state;
 	bool is_genpd;
+	struct icc_path *path;
 
 	int (*set_opp)(struct dev_pm_set_opp_data *data);
 	struct dev_pm_set_opp_data *set_opp_data;
diff --git a/include/linux/pm_opp.h b/include/linux/pm_opp.h
index 900359342965..5edce71a15d6 100644
--- a/include/linux/pm_opp.h
+++ b/include/linux/pm_opp.h
@@ -43,6 +43,18 @@ 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
@@ -127,6 +139,8 @@ struct opp_table *dev_pm_opp_set_regulators(struct device *dev, const char * con
 void dev_pm_opp_put_regulators(struct opp_table *opp_table);
 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);
+struct opp_table *dev_pm_opp_set_path(struct device *dev, const char *name);
+void dev_pm_opp_put_path(struct opp_table *opp_table);
 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);
 struct opp_table *dev_pm_opp_set_genpd_virt_dev(struct device *dev, struct device *virt_dev, int index);