On Thu, Jul 30, 2015 at 12:54:07PM -0400, Dan Williams wrote:
diff --git a/include/linux/io.h b/include/linux/io.h
index fb5a99800e77..3fcf6256c088 100644
@@ -121,4 +121,13 @@ static inline int arch_phys_wc_index(int handle)
+ /* See memremap() kernel-doc for usage description... */
+ MEMREMAP_WB = 1 << 0,
+ MEMREMAP_WT = 1 << 1,
Same feedback for enum nameing and also kdoc style.
diff --git a/kernel/memremap.c b/kernel/memremap.c
new file mode 100644
<-- ... -->
+ * memremap() - remap an iomem_resource as cacheable memory
+ * @offset: iomem resource start address
+ * @size: size of remap
+ * @flags: either MEMREMAP_WB or MEMREMAP_WT
+ * memremap() is "ioremap" for cases where it is known that the resource
+ * being mapped does not have i/o side effects and the __iomem
+ * annotation is not applicable.
+ * MEMREMAP_WB - matches the default mapping for "System RAM" on
+ * the architecture. This is usually a read-allocate write-back cache.
+ * Morever, if MEMREMAP_WB is specified and the requested remap region is RAM
+ * memremap() will bypass establishing a new mapping and instead return
+ * a pointer into the direct map.
+ * MEMREMAP_WT - establish a mapping whereby writes either bypass the
+ * cache or are written through to memory and never exist in a
+ * cache-dirty state with respect to program visibility. Attempts to
+ * map "System RAM" with this mapping type will fail.
Then you can extrend all this on kdoc on the enum.
+void *memremap(resource_size_t offset, size_t size, unsigned long flags)
+ int is_ram = region_intersects(offset, size, "System RAM");
This could be the enum region_intersect_type, then if the region enum is
extended you'd get a compiler error if one type was not handled.