[PATCH] of: reserved_mem: Introduce devres-managed initialization functions

[Konrad Dybcio]

Introduce devres-based helpers for of_reserved_mem_device_init(_by_idx)
to help fight dangling references and ever so slightly reduce the
number of boilerplate deinitialization calls.

Signed-off-by: Konrad Dybcio <konrad.dybcio@xxxxxxxxxxxxxxxx>
---
 drivers/of/of_reserved_mem.c    | 37 +++++++++++++++++++++++++++++++++
 include/linux/of_reserved_mem.h | 25 ++++++++++++++++++++++
 2 files changed, 62 insertions(+)

diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
index 82222bd45ac6..79fa04d4cf04 100644
--- a/drivers/of/of_reserved_mem.c
+++ b/drivers/of/of_reserved_mem.c
@@ -787,6 +787,43 @@ void of_reserved_mem_device_release(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(of_reserved_mem_device_release);
 
+static void devm_of_reserved_mem_device_release(struct device *dev, void *res)
+{
+	of_reserved_mem_device_release(*(struct device **)res);
+}
+
+/**
+ * devm_of_reserved_mem_device_init_by_idx - Resource managed of_reserved_mem_device_init_by_idx()
+ * @dev: Pointer to the device to configure
+ *
+ * This function assigns respective DMA-mapping operations based on the first
+ * reserved memory region specified by 'memory-region' property in device tree
+ * node of the given device.
+ *
+ * Returns: Negative errno on failure or zero on success.
+ */
+int devm_of_reserved_mem_device_init_by_idx(struct device *dev, struct device_node *np, int idx)
+{
+	struct device **ptr;
+	int ret;
+
+	ptr = devres_alloc(devm_of_reserved_mem_device_release, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return -ENOMEM;
+
+	ret = of_reserved_mem_device_init_by_idx(dev, np, idx);
+	if (ret) {
+		devres_free(ptr);
+		return ret;
+	}
+
+	*ptr = dev;
+	devres_add(dev, ptr);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(devm_of_reserved_mem_device_init_by_idx);
+
 /**
  * of_reserved_mem_lookup() - acquire reserved_mem from a device node
  * @np:		node pointer of the desired reserved-memory region
diff --git a/include/linux/of_reserved_mem.h b/include/linux/of_reserved_mem.h
index e8b20b29fa68..28beeeb91f4e 100644
--- a/include/linux/of_reserved_mem.h
+++ b/include/linux/of_reserved_mem.h
@@ -47,6 +47,8 @@ int of_reserved_mem_region_to_resource_byname(const struct device_node *np,
 					      const char *name, struct resource *res);
 int of_reserved_mem_region_count(const struct device_node *np);
 
+int devm_of_reserved_mem_device_init_by_idx(struct device *dev, struct device_node *np, int idx);
+
 #else
 
 #define RESERVEDMEM_OF_DECLARE(name, compat, ops)			\
@@ -91,6 +93,14 @@ static inline int of_reserved_mem_region_count(const struct device_node *np)
 {
 	return 0;
 }
+
+static inline int devm_of_reserved_mem_device_init_by_idx(struct device *dev,
+							  struct device_node *np,
+							  int idx)
+{
+	return -ENOSYS;
+}
+
 #endif
 
 /**
@@ -108,4 +118,19 @@ static inline int of_reserved_mem_device_init(struct device *dev)
 	return of_reserved_mem_device_init_by_idx(dev, dev->of_node, 0);
 }
 
+/**
+ * of_reserved_mem_device_init() - Devres-managed version of of_reserved_mem_device_init()
+ * @dev:	Pointer to the device to configure
+ *
+ * This function assigns respective DMA-mapping operations based on the first
+ * reserved memory region specified by 'memory-region' property in device tree
+ * node of the given device.
+ *
+ * Returns error code or zero on success.
+ */
+static inline int devm_of_reserved_mem_device_init(struct device *dev)
+{
+	return devm_of_reserved_mem_device_init_by_idx(dev, dev->of_node, 0);
+}
+
 #endif /* __OF_RESERVED_MEM_H */
-- 
2.54.0


Konrad