4 files changed, 49 insertions, 2 deletions

diff --git a/drivers/of/address.c b/drivers/of/address.c
index 5edfcb0da37d..e3718250d66e 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -702,6 +702,42 @@ void __iomem *of_iomap(struct device_node *np, int index)
 }
 EXPORT_SYMBOL(of_iomap);
 
+/*
+ * of_io_request_and_map - Requests a resource and maps the memory mapped IO
+ *                         for a given device_node
+ * @device:     the device whose io range will be mapped
+ * @index:      index of the io range
+ * @name:       name of the resource
+ *
+ * Returns a pointer to the requested and mapped memory or an ERR_PTR() encoded
+ * error code on failure. Usage example:
+ *
+ *      base = of_io_request_and_map(node, 0, "foo");
+ *      if (IS_ERR(base))
+ *              return PTR_ERR(base);
+ */
+void __iomem *of_io_request_and_map(struct device_node *np, int index,
+                                        char *name)
+{
+        struct resource res;
+        void __iomem *mem;
+
+        if (of_address_to_resource(np, index, &res))
+                return IOMEM_ERR_PTR(-EINVAL);
+
+        if (!request_mem_region(res.start, resource_size(&res), name))
+                return IOMEM_ERR_PTR(-EBUSY);
+
+        mem = ioremap(res.start, resource_size(&res));
+        if (!mem) {
+                release_mem_region(res.start, resource_size(&res));
+                return IOMEM_ERR_PTR(-ENOMEM);
+        }
+
+        return mem;
+}
+EXPORT_SYMBOL(of_io_request_and_map);
+
 /**
  * of_dma_get_range - Get DMA range info
  * @np:         device node to get DMA range info
diff --git a/include/linux/io.h b/include/linux/io.h
index b76e6e545806..d5fc9b8d8b03 100644
--- a/include/linux/io.h
+++ b/include/linux/io.h
@@ -58,6 +58,8 @@ static inline void devm_ioport_unmap(struct device *dev, void __iomem *addr)
 }
 #endif
 
+#define IOMEM_ERR_PTR(err) (__force void __iomem *)ERR_PTR(err)
+
 void __iomem *devm_ioremap(struct device *dev, resource_size_t offset,
                             unsigned long size);
 void __iomem *devm_ioremap_nocache(struct device *dev, resource_size_t offset,
diff --git a/include/linux/of_address.h b/include/linux/of_address.h
index c13b8782a4eb..fb7b7221e063 100644
--- a/include/linux/of_address.h
+++ b/include/linux/of_address.h
@@ -109,7 +109,12 @@ static inline bool of_dma_is_coherent(struct device_node *np)
 extern int of_address_to_resource(struct device_node *dev, int index,
                                   struct resource *r);
 void __iomem *of_iomap(struct device_node *node, int index);
+void __iomem *of_io_request_and_map(struct device_node *device,
+                                        int index, char *name);
 #else
+
+#include <linux/io.h>
+
 static inline int of_address_to_resource(struct device_node *dev, int index,
                                          struct resource *r)
 {
@@ -120,6 +125,12 @@ static inline void __iomem *of_iomap(struct device_node *device, int index)
 {
         return NULL;
 }
+
+static inline void __iomem *of_io_request_and_map(struct device_node *device,
+                                        int index, char *name)
+{
+        return IOMEM_ERR_PTR(-EINVAL);
+}
 #endif
 
 #if defined(CONFIG_OF_ADDRESS) && defined(CONFIG_PCI)
diff --git a/lib/devres.c b/lib/devres.c
index f562bf6ff71d..bb632484a860 100644
--- a/lib/devres.c
+++ b/lib/devres.c
@@ -86,8 +86,6 @@ void devm_iounmap(struct device *dev, void __iomem *addr)
 }
 EXPORT_SYMBOL(devm_iounmap);
 
-#define IOMEM_ERR_PTR(err) (__force void __iomem *)ERR_PTR(err)
-
 /**
  * devm_ioremap_resource() - check, request region, and ioremap resource
  * @dev: generic device to handle the resource for