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Subject[PATCH 2/3] PM / OPP: Parse 'opp-supported-hw' binding
Date
OPP bindings allow a platform to enable OPPs based on the version of the
hardware they are used for.

Add support to the OPP-core to parse these bindings, by introducing
dev_pm_opp_{set|put}_supported_hw() APIs.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
drivers/base/power/opp/core.c | 153 ++++++++++++++++++++++++++++++++++++++++++
drivers/base/power/opp/opp.h | 5 ++
include/linux/pm_opp.h | 12 ++++
3 files changed, 170 insertions(+)

diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c
index 6aa172be6e8e..29fe251bf9ec 100644
--- a/drivers/base/power/opp/core.c
+++ b/drivers/base/power/opp/core.c
@@ -559,6 +559,9 @@ static void _remove_device_opp(struct device_opp *dev_opp)
if (!list_empty(&dev_opp->opp_list))
return;

+ if (dev_opp->supported_hw)
+ return;
+
list_dev = list_first_entry(&dev_opp->dev_list, struct device_list_opp,
node);

@@ -834,6 +837,150 @@ static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev)
}

/**
+ * dev_pm_opp_set_supported_hw() - Set supported platforms
+ * @dev: Device for which the regulator has to be set.
+ * @versions: Array of hierarchy of versions to match.
+ * @count: Number of elements in the array.
+ *
+ * This is required only for the V2 bindings, and it enables a platform to
+ * specify the hierarchy of versions it supports. OPP layer will then enable
+ * OPPs, which are available for those versions, based on its 'opp-supported-hw'
+ * property.
+ */
+int dev_pm_opp_set_supported_hw(struct device *dev, u32 *versions,
+ unsigned int count)
+{
+ struct device_opp *dev_opp;
+ int ret = 0;
+
+ if (!dev || !versions || !count) {
+ pr_err("%s: Invalid arguments, dev:0x%p, ver:0x%p, count:%u\n",
+ __func__, dev, versions, count);
+ return -EINVAL;
+ }
+
+ /* Operations on OPP structures must be done from within rcu locks */
+ rcu_read_lock();
+
+ dev_opp = _add_device_opp(dev);
+ if (!dev_opp)
+ return -ENOMEM;
+
+ /* Do we already have a version hierarchy associated with dev_opp? */
+ if (dev_opp->supported_hw) {
+ dev_err(dev, "%s: Already have supported hardware list\n",
+ __func__);
+ ret = -EINVAL;
+ goto unlock;
+ }
+
+ dev_opp->supported_hw = kmemdup(versions, count * sizeof(*versions),
+ GFP_KERNEL);
+ if (!dev_opp->supported_hw) {
+ ret = -ENOMEM;
+ goto unlock;
+ }
+
+ dev_opp->supported_hw_count = count;
+
+unlock:
+ rcu_read_unlock();
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_set_supported_hw);
+
+/**
+ * dev_pm_opp_put_supported_hw() - Releases resources blocked for supported hw
+ * @dev: Device for which the regulator has to be set.
+ *
+ * This is required only for the V2 bindings, and is called for a matching
+ * dev_pm_opp_set_supported_hw(). Until this is called, the device_opp structure
+ * will not be freed.
+ */
+void dev_pm_opp_put_supported_hw(struct device *dev)
+{
+ struct device_opp *dev_opp;
+
+ if (!dev) {
+ pr_err("%s: Invalid argument dev:0x%p\n", __func__, dev);
+ return;
+ }
+
+ /* Operations on OPP structures must be done from within rcu locks */
+ rcu_read_lock();
+
+ /* Check for existing list for 'dev' first */
+ dev_opp = _find_device_opp(dev);
+ if (IS_ERR(dev_opp)) {
+ dev_err(dev, "Failed to find dev_opp: %ld\n", PTR_ERR(dev_opp));
+ goto unlock;
+ }
+
+ if (!dev_opp->supported_hw) {
+ dev_err(dev, "%s: Doesn't have supported hardware list\n",
+ __func__);
+ goto unlock;
+ }
+
+ kfree(dev_opp->supported_hw);
+ dev_opp->supported_hw = NULL;
+ dev_opp->supported_hw_count = 0;
+
+ /* Try freeing device_opp if this was the last blocking resource */
+ _remove_device_opp(dev_opp);
+
+unlock:
+ rcu_read_unlock();
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_put_supported_hw);
+
+static bool _opp_is_supported(struct device *dev, struct device_opp *dev_opp,
+ struct device_node *np)
+{
+ unsigned int count;
+ u32 *versions;
+ bool supported = true;
+ int ret;
+
+ if (!dev_opp->supported_hw)
+ return true;
+
+ count = of_property_count_u32_elems(np, "opp-supported-hw");
+ if (count != dev_opp->supported_hw_count) {
+ dev_warn(dev, "%s: supported-hw count mismatch, plat:%u != DT:%u\n",
+ __func__, dev_opp->supported_hw_count, count);
+ return false;
+ }
+
+ versions = kcalloc(count, sizeof(*versions), GFP_KERNEL);
+ if (!versions)
+ return false;
+
+ ret = of_property_read_u32_array(np, "opp-supported-hw", versions,
+ count);
+ if (ret) {
+ dev_warn(dev, "%s: failed to read opp-supported-hw property: %d\n",
+ __func__, ret);
+ supported = false;
+ goto free_versions;
+ }
+
+ while (count--) {
+ /* Both of these are bitwise masks of the versions */
+ if (!(versions[count] & dev_opp->supported_hw[count])) {
+ supported = false;
+ break;
+ }
+ }
+
+free_versions:
+ kfree(versions);
+
+ return supported;
+}
+
+/**
* _opp_add_static_v2() - Allocate static OPPs (As per 'v2' DT bindings)
* @dev: device for which we do this operation
* @np: device node
@@ -879,6 +1026,12 @@ static int _opp_add_static_v2(struct device *dev, struct device_node *np)
goto free_opp;
}

+ /* Check if the OPP supports hardware's hierarchy of versions or not */
+ if (!_opp_is_supported(dev, dev_opp, np)) {
+ dev_dbg(dev, "OPP not supported by hardware: %llu\n", rate);
+ goto free_opp;
+ }
+
/*
* Rate is defined as an unsigned long in clk API, and so casting
* explicitly to its type. Must be fixed once rate is 64 bit
diff --git a/drivers/base/power/opp/opp.h b/drivers/base/power/opp/opp.h
index b8880c7f8be1..70f4564a6ab9 100644
--- a/drivers/base/power/opp/opp.h
+++ b/drivers/base/power/opp/opp.h
@@ -129,6 +129,8 @@ struct device_list_opp {
* @clock_latency_ns_max: Max clock latency in nanoseconds.
* @shared_opp: OPP is shared between multiple devices.
* @suspend_opp: Pointer to OPP to be used during device suspend.
+ * @supported_hw: Array of version number to support.
+ * @supported_hw_count: Number of elements in supported_hw array.
* @dentry: debugfs dentry pointer of the real device directory (not links).
* @dentry_name: Name of the real dentry.
*
@@ -153,6 +155,9 @@ struct device_opp {
bool shared_opp;
struct dev_pm_opp *suspend_opp;

+ unsigned int *supported_hw;
+ unsigned int supported_hw_count;
+
#ifdef CONFIG_DEBUG_FS
struct dentry *dentry;
char dentry_name[NAME_MAX];
diff --git a/include/linux/pm_opp.h b/include/linux/pm_opp.h
index 9a2e50337af9..d12471ed14a2 100644
--- a/include/linux/pm_opp.h
+++ b/include/linux/pm_opp.h
@@ -55,6 +55,9 @@ int dev_pm_opp_enable(struct device *dev, unsigned long freq);
int dev_pm_opp_disable(struct device *dev, unsigned long freq);

struct srcu_notifier_head *dev_pm_opp_get_notifier(struct device *dev);
+int dev_pm_opp_set_supported_hw(struct device *dev, u32 *versions,
+ unsigned int count);
+void dev_pm_opp_put_supported_hw(struct device *dev);
#else
static inline unsigned long dev_pm_opp_get_voltage(struct dev_pm_opp *opp)
{
@@ -129,6 +132,15 @@ static inline struct srcu_notifier_head *dev_pm_opp_get_notifier(
{
return ERR_PTR(-EINVAL);
}
+
+static inline int dev_pm_opp_set_supported_hw(struct device *dev, u32 *versions,
+ unsigned int count)
+{
+ return -EINVAL;
+}
+
+static inline void dev_pm_opp_put_supported_hw(struct device *dev) {}
+
#endif /* CONFIG_PM_OPP */

#if defined(CONFIG_PM_OPP) && defined(CONFIG_OF)
--
2.6.2.198.g614a2ac


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