PM / OPP: Parse 'opp-supported-hw' binding

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>
Tested-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
(cherry picked from commit 7de36b0aa51a5a59e28fb2da768fa3ab07de0674)
Signed-off-by: Alex Shi <alex.shi@linaro.org>

diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c
index 6aa172be6e8e8b26cb0ece81bd7fab71546e5ce8..55cf1a99b532caf5bcd30bab27787aaf0b192617 100644 (file)
--- 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);
 
@@ -833,6 +836,145 @@ static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev)
        return 0;
 }
 
+/**
+ * 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 enable
+ * OPPs, which are available for those versions, based on its 'opp-supported-hw'
+ * property.
+ *
+ * Locking: The internal device_opp and opp structures are RCU protected.
+ * Hence this function internally uses RCU updater strategy with mutex locks
+ * to keep the integrity of the internal data structures. Callers should ensure
+ * that this function is *NOT* called under RCU protection or in contexts 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 = 0;
+
+       /* Hold our list modification lock here */
+       mutex_lock(&dev_opp_list_lock);
+
+       dev_opp = _add_device_opp(dev);
+       if (!dev_opp) {
+               ret = -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 = -EBUSY;
+               goto err;
+       }
+
+       dev_opp->supported_hw = kmemdup(versions, count * sizeof(*versions),
+                                       GFP_KERNEL);
+       if (!dev_opp->supported_hw) {
+               ret = -ENOMEM;
+               goto err;
+       }
+
+       dev_opp->supported_hw_count = 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 supported hw
+ * @dev: Device for which supported-hw 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.
+ *
+ * Locking: The internal device_opp and opp structures are RCU protected.
+ * Hence this function internally uses RCU updater strategy with mutex locks
+ * to keep the integrity of the internal data structures. Callers should ensure
+ * that this function is *NOT* called under RCU protection or in contexts 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 = _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 = NULL;
+       dev_opp->supported_hw_count = 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 = dev_opp->supported_hw_count;
+       u32 version;
+       int ret;
+
+       if (!dev_opp->supported_hw)
+               return true;
+
+       while (count--) {
+               ret = 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
@@ -879,6 +1021,12 @@ 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 b8880c7f8be1c6c47b5ebf94663c79e47098c65f..70f4564a6ab9d5274fd7f95b18777fad58eab42b 100644 (file)
--- 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 9a2e50337af9fd233656b8fb6f06a91c10b2e7bf..3a85110242f004c78d4fab8ff007659e2b2be265 100644 (file)
--- 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, 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 *opp)
 {
@@ -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 */
 
 #if defined(CONFIG_PM_OPP) && defined(CONFIG_OF)