Add devm_arch_io_reserve_memtype_wc() as managed wrapper around
arch_io_reserve_memtype_wc(). Useful for several grahpics drivers
that set framebuffer memory to write combining.

Signed-off-by: Thomas Zimmermann <tzimmerm...@suse.de>
---
 include/linux/io.h |  3 +++
 lib/devres.c       | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 49 insertions(+)

diff --git a/include/linux/io.h b/include/linux/io.h
index fcd8ea79c5df..5fc800390fe4 100644
--- a/include/linux/io.h
+++ b/include/linux/io.h
@@ -168,4 +168,7 @@ static inline void arch_io_free_memtype_wc(resource_size_t 
base,
 }
 #endif
 
+int devm_arch_io_reserve_memtype_wc(struct device *dev, resource_size_t start,
+                                   resource_size_t size);
+
 #endif /* _LINUX_IO_H */
diff --git a/lib/devres.c b/lib/devres.c
index 24d4d849ff67..14664bbb4875 100644
--- a/lib/devres.c
+++ b/lib/devres.c
@@ -564,3 +564,49 @@ int devm_arch_phys_wc_add(struct device *dev, unsigned 
long base, unsigned long
        return ret;
 }
 EXPORT_SYMBOL(devm_arch_phys_wc_add);
+
+struct arch_io_reserve_memtype_wc_devres {
+       resource_size_t start;
+       resource_size_t size;
+};
+
+static void devm_arch_io_free_memtype_wc_release(struct device *dev, void *res)
+{
+       const struct arch_io_reserve_memtype_wc_devres *this = res;
+
+       arch_io_free_memtype_wc(this->start, this->size);
+}
+
+/**
+ * devm_arch_io_reserve_memtype_wc - Managed arch_io_reserve_memtype_wc()
+ * @dev: Managed device
+ * @start: Memory base address
+ * @size: Size of memory range
+ *
+ * Reserves a memory range with WC caching using arch_io_reserve_memtype_wc()
+ * and sets up a release callback See arch_io_reserve_memtype_wc() for more
+ * information.
+ */
+int devm_arch_io_reserve_memtype_wc(struct device *dev, resource_size_t start,
+                                   resource_size_t size)
+{
+       struct arch_io_reserve_memtype_wc_devres *dr;
+       int ret;
+
+       dr = devres_alloc(devm_arch_io_free_memtype_wc_release, sizeof(*dr), 
GFP_KERNEL);
+       if (!dr)
+               return -ENOMEM;
+
+       ret = arch_io_reserve_memtype_wc(start, size);
+       if (ret < 0) {
+               devres_free(dr);
+               return ret;
+       }
+
+       dr->start = start;
+       dr->size = size;
+       devres_add(dev, dr);
+
+       return ret;
+}
+EXPORT_SYMBOL(devm_arch_io_reserve_memtype_wc);
-- 
2.33.0

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