[PATCH 4.4.y-cip v3 07/14] PM / OPP: Parse 'opp-supported-hw' binding


Chen-Yu Tsai (Moxa) <wens@...>
 

From: Viresh Kumar <viresh.kumar@...>

commit 7de36b0aa51a5a59e28fb2da768fa3ab07de0674 upstream.

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@...>
Tested-by: Lee Jones <lee.jones@...>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...>
Signed-off-by: Chen-Yu Tsai (Moxa) <wens@...>
---
drivers/base/power/opp/core.c | 148 ++++++++++++++++++++++++++++++++++
drivers/base/power/opp/opp.h | 5 ++
include/linux/pm_opp.h | 13 +++
3 files changed, 166 insertions(+)

diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.=
c
index 22d91d9b1b037..a73433c3cbe45 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;
=20
+ if (dev_opp->supported_hw)
+ return;
+
list_dev =3D list_first_entry(&dev_opp->dev_list, struct device_list_op=
p,
node);
=20
@@ -839,6 +842,145 @@ static int opp_parse_supplies(struct dev_pm_opp *op=
p, struct device *dev)
return 0;
}
=20
+/**
+ * dev_pm_opp_set_supported_hw() - Set supported platforms
+ * @dev: Device for which supported-hw 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 en=
able
+ * OPPs, which are available for those versions, based on its 'opp-suppo=
rted-hw'
+ * property.
+ *
+ * Locking: The internal device_opp and opp structures are RCU protected=
.
+ * Hence this function internally uses RCU updater strategy with mutex l=
ocks
+ * to keep the integrity of the internal data structures. Callers should=
ensure
+ * that this function is *NOT* called under RCU protection or in context=
s where
+ * mutex cannot be locked.
+ */
+int dev_pm_opp_set_supported_hw(struct device *dev, const u32 *versions,
+ unsigned int count)
+{
+ struct device_opp *dev_opp;
+ int ret =3D 0;
+
+ /* Hold our list modification lock here */
+ mutex_lock(&dev_opp_list_lock);
+
+ dev_opp =3D _add_device_opp(dev);
+ if (!dev_opp) {
+ ret =3D -ENOMEM;
+ goto unlock;
+ }
+
+ /* Make sure there are no concurrent readers while updating dev_opp */
+ WARN_ON(!list_empty(&dev_opp->opp_list));
+
+ /* 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 =3D -EBUSY;
+ goto err;
+ }
+
+ dev_opp->supported_hw =3D kmemdup(versions, count * sizeof(*versions),
+ GFP_KERNEL);
+ if (!dev_opp->supported_hw) {
+ ret =3D -ENOMEM;
+ goto err;
+ }
+
+ dev_opp->supported_hw_count =3D count;
+ mutex_unlock(&dev_opp_list_lock);
+ return 0;
+
+err:
+ _remove_device_opp(dev_opp);
+unlock:
+ mutex_unlock(&dev_opp_list_lock);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_set_supported_hw);
+
+/**
+ * dev_pm_opp_put_supported_hw() - Releases resources blocked for suppor=
ted hw
+ * @dev: Device for which supported-hw has to be set.
+ *
+ * This is required only for the V2 bindings, and is called for a matchi=
ng
+ * dev_pm_opp_set_supported_hw(). Until this is called, the device_opp s=
tructure
+ * will not be freed.
+ *
+ * Locking: The internal device_opp and opp structures are RCU protected=
.
+ * Hence this function internally uses RCU updater strategy with mutex l=
ocks
+ * to keep the integrity of the internal data structures. Callers should=
ensure
+ * that this function is *NOT* called under RCU protection or in context=
s where
+ * mutex cannot be locked.
+ */
+void dev_pm_opp_put_supported_hw(struct device *dev)
+{
+ struct device_opp *dev_opp;
+
+ /* Hold our list modification lock here */
+ mutex_lock(&dev_opp_list_lock);
+
+ /* Check for existing list for 'dev' first */
+ dev_opp =3D _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;
+ }
+
+ /* Make sure there are no concurrent readers while updating dev_opp */
+ WARN_ON(!list_empty(&dev_opp->opp_list));
+
+ 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 =3D NULL;
+ dev_opp->supported_hw_count =3D 0;
+
+ /* Try freeing device_opp if this was the last blocking resource */
+ _remove_device_opp(dev_opp);
+
+unlock:
+ mutex_unlock(&dev_opp_list_lock);
+}
+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 =3D dev_opp->supported_hw_count;
+ u32 version;
+ int ret;
+
+ if (!dev_opp->supported_hw)
+ return true;
+
+ while (count--) {
+ ret =3D of_property_read_u32_index(np, "opp-supported-hw", count,
+ &version);
+ if (ret) {
+ dev_warn(dev, "%s: failed to read opp-supported-hw property at index =
%d: %d\n",
+ __func__, count, ret);
+ return false;
+ }
+
+ /* Both of these are bitwise masks of the versions */
+ if (!(version & dev_opp->supported_hw[count]))
+ return false;
+ }
+
+ return true;
+}
+
/**
* _opp_add_static_v2() - Allocate static OPPs (As per 'v2' DT bindings)
* @dev: device for which we do this operation
@@ -885,6 +1027,12 @@ static int _opp_add_static_v2(struct device *dev, s=
truct device_node *np)
goto free_opp;
}
=20
+ /* 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 b8880c7f8be1c..70f4564a6ab9d 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 lin=
ks).
* @dentry_name: Name of the real dentry.
*
@@ -153,6 +155,9 @@ struct device_opp {
bool shared_opp;
struct dev_pm_opp *suspend_opp;
=20
+ 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 9a2e50337af9f..3a85110242f00 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);
=20
struct srcu_notifier_head *dev_pm_opp_get_notifier(struct device *dev);
+int dev_pm_opp_set_supported_hw(struct device *dev, const 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 *op=
p)
{
@@ -129,6 +132,16 @@ 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,
+ const u32 *versions,
+ unsigned int count)
+{
+ return -EINVAL;
+}
+
+static inline void dev_pm_opp_put_supported_hw(struct device *dev) {}
+
#endif /* CONFIG_PM_OPP */
=20
#if defined(CONFIG_PM_OPP) && defined(CONFIG_OF)
--=20
2.27.0.rc0

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