[PATCH v3 05/24] arch: introduce memremap()
From: Luis R. Rodriguez <hidden>
Date: 2015-07-30 21:02:09
Also in:
linux-arch, lkml, nvdimm
On Thu, Jul 30, 2015 at 12:54:07PM -0400, Dan Williams wrote:
quoted hunk ↗ jump to hunk
diff --git a/include/linux/io.h b/include/linux/io.h index fb5a99800e77..3fcf6256c088 100644 --- a/include/linux/io.h +++ b/include/linux/io.h@@ -121,4 +121,13 @@ static inline int arch_phys_wc_index(int handle) #endif #endif +enum { + /* See memremap() kernel-doc for usage description... */ + MEMREMAP_WB = 1 << 0, + MEMREMAP_WT = 1 << 1, +};
Same feedback for enum nameing and also kdoc style.
quoted hunk ↗ jump to hunk
diff --git a/kernel/memremap.c b/kernel/memremap.c new file mode 100644 index 000000000000..27637f42f30d --- /dev/null +++ b/kernel/memremap.c
<-- ... -->
+/** + * 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. Luis