add devm_memremap_pages

This behaves like devm_memremap except that it ensures we have page
structures available that can back the region.

Signed-off-by: Christoph Hellwig <hch@lst.de>
[djbw: catch attempts to remap RAM, drop flags]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 20 insertions, 0 deletions

diff --git a/include/linux/io.h b/include/linux/io.h
index d8d749a..de64c1e 100644
--- a/include/linux/io.h
+++ b/include/linux/io.h
@@ -20,10 +20,13 @@
 
 #include <linux/types.h>
 #include <linux/init.h>
+#include <linux/bug.h>
+#include <linux/err.h>
 #include <asm/io.h>
 #include <asm/page.h>
 
 struct device;
+struct resource;
 
 __visible void __iowrite32_copy(void __iomem *to, const void *from, size_t count);
 void __iowrite64_copy(void __iomem *to, const void *from, size_t count);
@@ -84,6 +87,23 @@ void *devm_memremap(struct device *dev, resource_size_t offset,
 		size_t size, unsigned long flags);
 void devm_memunmap(struct device *dev, void *addr);
 
+void *__devm_memremap_pages(struct device *dev, struct resource *res);
+
+#ifdef CONFIG_ZONE_DEVICE
+void *devm_memremap_pages(struct device *dev, struct resource *res);
+#else
+static inline void *devm_memremap_pages(struct device *dev, struct resource *res)
+{
+	/*
+	 * Fail attempts to call devm_memremap_pages() without
+	 * ZONE_DEVICE support enabled, this requires callers to fall
+	 * back to plain devm_memremap() based on config
+	 */
+	WARN_ON_ONCE(1);
+	return ERR_PTR(-ENXIO);
+}
+#endif
+
 /*
  * Some systems do not have legacy ISA devices.
  * /dev/port is not a valid interface on these systems.