[PATCH 09/10] opp: Add helpers for initializing CPU OPPs

Viresh Kumar
2015-06-15T11:58:29Z

With "operating-points-v2" its possible to tell which devices share
OPPs. We already have infrastructure to decode that information.

This patch adds following APIs:
- of_get_cpus_sharing_opps: Returns cpumask of CPUs sharing OPPs (only
valid with v2 bindings).
- of_cpumask_init_opp_table: Initializes OPPs for all CPUs present in
cpumask.
- of_cpumask_free_opp_table: Frees OPPs for all CPUs present in cpumask.

- set_cpus_sharing_opps: Sets which CPUs share OPPs (only valid with old
OPP bindings, as this information isn't present in DT).

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
drivers/base/power/opp.c | 175 +++++++++++++++++++++++++++++++++++++++++++++++
include/linux/pm_opp.h | 23 +++++++
2 files changed, 198 insertions(+)

diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
index 0022453e4b60..e24502a2692f 100644
--- a/drivers/base/power/opp.c
+++ b/drivers/base/power/opp.c
@@ -11,6 +11,7 @@
* published by the Free Software Foundation.
*/

+#include <linux/cpu.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/err.h>
@@ -1162,6 +1163,26 @@ void of_free_opp_table(struct device *dev)
}
EXPORT_SYMBOL_GPL(of_free_opp_table);

+void of_cpumask_free_opp_table(cpumask_var_t cpumask)
+{
+ struct device *cpu_dev;
+ int cpu;
+
+ WARN_ON(cpumask_empty(cpumask));
+
+ for_each_cpu(cpu, cpumask) {
+ cpu_dev = get_cpu_device(cpu);
+ if (!cpu_dev) {
+ pr_err("%s: failed to get cpu%d device\n", __func__,
+ cpu);
+ continue;
+ }
+
+ of_free_opp_table(cpu_dev);
+ }
+}
+EXPORT_SYMBOL_GPL(of_cpumask_free_opp_table);
+
/* Returns opp descriptor node from its phandle. Caller must do of_node_put() */
static struct device_node *
_of_get_opp_desc_node_from_prop(struct device *dev, const struct property *prop)
@@ -1178,6 +1199,31 @@ _of_get_opp_desc_node_from_prop(struct device *dev, const struct property *prop)
return opp_np;
}

+/* Returns opp descriptor node for a device. Caller must do of_node_put() */
+static struct device_node *_of_get_opp_desc_node(struct device *dev)
+{
+ const struct property *prop;
+
+ prop = of_find_property(dev->of_node, "operating-points-v2", NULL);
+ if (!prop)
+ return ERR_PTR(-ENODEV);
+ if (!prop->value)
+ return ERR_PTR(-ENODATA);
+
+ /*
+ * TODO: Support for multiple OPP tables.
+ *
+ * There should be only ONE phandle present in "operating-points-v2"
+ * property.
+ */
+ if (prop->length != sizeof(__be32)) {
+ dev_err(dev, "%s: Invalid opp desc phandle\n", __func__);
+ return ERR_PTR(-EINVAL);
+ }
+
+ return _of_get_opp_desc_node_from_prop(dev, prop);
+}
+
/* Initializes OPP tables based on new bindings */
static int _of_init_opp_table_v2(struct device *dev,
const struct property *prop)
@@ -1338,4 +1384,133 @@ int of_init_opp_table(struct device *dev)
return _of_init_opp_table_v2(dev, prop);
}
EXPORT_SYMBOL_GPL(of_init_opp_table);
+
+int of_cpumask_init_opp_table(cpumask_var_t cpumask)
+{
+ struct device *cpu_dev;
+ int cpu, ret = 0;
+
+ WARN_ON(cpumask_empty(cpumask));
+
+ for_each_cpu(cpu, cpumask) {
+ cpu_dev = get_cpu_device(cpu);
+ if (!cpu_dev) {
+ pr_err("%s: failed to get cpu%d device\n", __func__,
+ cpu);
+ continue;
+ }
+
+ ret = of_init_opp_table(cpu_dev);
+ if (ret) {
+ pr_err("%s: couldn't find opp table for cpu:%d, %d\n",
+ __func__, cpu, ret);
+
+ /* Free all other OPPs */
+ of_cpumask_free_opp_table(cpumask);
+ break;
+ }
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(of_cpumask_init_opp_table);
+
+/* Required only for V1 bindings, as v2 can manage it from DT itself */
+int set_cpus_sharing_opps(struct device *cpu_dev, cpumask_var_t cpumask)
+{
+ struct device_list_opp *list_dev;
+ struct device_opp *dev_opp;
+ struct device *dev;
+ int cpu, ret = 0;
+
+ rcu_read_lock();
+
+ dev_opp = _find_device_opp(cpu_dev);
+ if (IS_ERR(dev_opp)) {
+ ret = -EINVAL;
+ goto out_rcu_read_unlock;
+ }
+
+ for_each_cpu(cpu, cpumask) {
+ if (cpu == cpu_dev->id)
+ continue;
+
+ dev = get_cpu_device(cpu);
+ if (!dev) {
+ dev_err(cpu_dev, "%s: failed to get cpu%d device\n",
+ __func__, cpu);
+ continue;
+ }
+
+ list_dev = _add_list_dev(dev, dev_opp);
+ if (!list_dev) {
+ dev_err(dev, "%s: failed to add list-dev for cpu%d device\n",
+ __func__, cpu);
+ continue;
+ }
+ }
+out_rcu_read_unlock:
+ rcu_read_unlock();
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(set_cpus_sharing_opps);
+
+/*
+ * Works only for OPP v2 bindings.
+ *
+ * cpumask should be already set to mask of cpu_dev->id.
+ * Returns -ENOENT if operating-points-v2 bindings aren't supported.
+ */
+int of_get_cpus_sharing_opps(struct device *cpu_dev, cpumask_var_t cpumask)
+{
+ struct device_node *np, *tmp_np;
+ struct device *tcpu_dev;
+ int cpu, ret = 0;
+
+ /* Get OPP descriptor node */
+ np = _of_get_opp_desc_node(cpu_dev);
+ if (IS_ERR(np)) {
+ dev_dbg(cpu_dev, "%s: Couldn't find opp node: %ld\n", __func__,
+ PTR_ERR(np));
+ return -ENOENT;
+ }
+
+ /* OPPs are shared ? */
+ if (!of_get_property(np, "opp-shared", NULL))
+ goto put_cpu_node;
+
+ for_each_possible_cpu(cpu) {
+ if (cpu == cpu_dev->id)
+ continue;
+
+ tcpu_dev = get_cpu_device(cpu);
+ if (!tcpu_dev) {
+ dev_err(cpu_dev, "%s: failed to get cpu%d device\n",
+ __func__, cpu);
+ ret = -ENODEV;
+ goto put_cpu_node;
+ }
+
+ /* Get OPP descriptor node */
+ tmp_np = _of_get_opp_desc_node(tcpu_dev);
+ if (IS_ERR(tmp_np)) {
+ dev_info(tcpu_dev, "%s: Couldn't find opp node: %ld\n",
+ __func__, PTR_ERR(tmp_np));
+ ret = -EINVAL;
+ goto put_cpu_node;
+ }
+
+ /* CPUs are sharing opp node */
+ if (np == tmp_np)
+ cpumask_set_cpu(cpu, cpumask);
+
+ of_node_put(tmp_np);
+ }
+
+put_cpu_node:
+ of_node_put(np);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(of_get_cpus_sharing_opps);
#endif
diff --git a/include/linux/pm_opp.h b/include/linux/pm_opp.h
index 20324b579adc..bb52fae5b921 100644
--- a/include/linux/pm_opp.h
+++ b/include/linux/pm_opp.h
@@ -121,6 +121,10 @@ static inline struct srcu_notifier_head *dev_pm_opp_get_notifier(
#if defined(CONFIG_PM_OPP) && defined(CONFIG_OF)
int of_init_opp_table(struct device *dev);
void of_free_opp_table(struct device *dev);
+int of_cpumask_init_opp_table(cpumask_var_t cpumask);
+void of_cpumask_free_opp_table(cpumask_var_t cpumask);
+int of_get_cpus_sharing_opps(struct device *cpu_dev, cpumask_var_t cpumask);
+int set_cpus_sharing_opps(struct device *cpu_dev, cpumask_var_t cpumask);
#else
static inline int of_init_opp_table(struct device *dev)
{
@@ -130,6 +134,25 @@ static inline int of_init_opp_table(struct device *dev)
static inline void of_free_opp_table(struct device *dev)
{
}
+
+static inline int of_cpumask_init_opp_table(cpumask_var_t cpumask)
+{
+ return -ENOSYS;
+}
+
+static inline void of_cpumask_free_opp_table(cpumask_var_t cpumask)
+{
+}
+
+static inline int of_get_cpus_sharing_opps(struct device *cpu_dev, cpumask_var_t cpumask)
+{
+ return -ENOSYS;
+}
+
+static inline int set_cpus_sharing_opps(struct device *cpu_dev, cpumask_var_t cpumask)
+{
+ return -ENOSYS;
+}
#endif

#endif /* __LINUX_OPP_H__ */
--
2.4.0