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Subject[PATCH 2/4] OPP: Add support for parsing the interconnect bandwidth
Date
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@linaro.org>
---
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);
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