Merge tag 'ofs-pull-tag-1' of git://git.kernel.org/pub/scm/linux/kernel/git/hubcap...

[cascardo/linux.git] / kernel / memremap.c

diff --git a/kernel/memremap.c b/kernel/memremap.c
index 6cf5461..a6d3823 100644 (file)
--- a/kernel/memremap.c
+++ b/kernel/memremap.c
@@ -41,13 +41,15 @@ static void *try_ram_remap(resource_size_t offset, size_t size)
  * memremap() - remap an iomem_resource as cacheable memory
  * @offset: iomem resource start address
  * @size: size of remap
- * @flags: either MEMREMAP_WB or MEMREMAP_WT
+ * @flags: any of MEMREMAP_WB, MEMREMAP_WT and MEMREMAP_WC
  *
  * 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.
+ * annotation is not applicable. In the case of multiple flags, the different
+ * mapping types will be attempted in the order listed below until one of
+ * them succeeds.
  *
- * MEMREMAP_WB - matches the default mapping for "System RAM" on
+ * 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
@@ -56,13 +58,21 @@ static void *try_ram_remap(resource_size_t offset, size_t size)
  * 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.
+ * map System RAM with this mapping type will fail.
+ *
+ * MEMREMAP_WC - establish a writecombine mapping, whereby writes may
+ * be coalesced together (e.g. in the CPU's write buffers), but is otherwise
+ * uncached. Attempts to map System RAM with this mapping type will fail.
  */
 void *memremap(resource_size_t offset, size_t size, unsigned long flags)
 {
-       int is_ram = region_intersects(offset, size, "System RAM");
+       int is_ram = region_intersects(offset, size,
+                                      IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE);
        void *addr = NULL;
 
+       if (!flags)
+               return NULL;
+
        if (is_ram == REGION_MIXED) {
                WARN_ONCE(1, "memremap attempted on mixed range %pa size: %#lx\n",
                                &offset, (unsigned long) size);
@@ -71,12 +81,11 @@ void *memremap(resource_size_t offset, size_t size, unsigned long flags)
 
        /* Try all mapping types requested until one returns non-NULL */
        if (flags & MEMREMAP_WB) {
-               flags &= ~MEMREMAP_WB;
                /*
                 * MEMREMAP_WB is special in that it can be satisifed
                 * from the direct map.  Some archs depend on the
                 * capability of memremap() to autodetect cases where
-                * the requested range is potentially in "System RAM"
+                * the requested range is potentially in System RAM.
                 */
                if (is_ram == REGION_INTERSECTS)
                        addr = try_ram_remap(offset, size);
@@ -85,21 +94,22 @@ void *memremap(resource_size_t offset, size_t size, unsigned long flags)
        }
 
        /*
-        * If we don't have a mapping yet and more request flags are
-        * pending then we will be attempting to establish a new virtual
+        * If we don't have a mapping yet and other request flags are
+        * present then we will be attempting to establish a new virtual
         * address mapping.  Enforce that this mapping is not aliasing
-        * "System RAM"
+        * System RAM.
         */
-       if (!addr && is_ram == REGION_INTERSECTS && flags) {
+       if (!addr && is_ram == REGION_INTERSECTS && flags != MEMREMAP_WB) {
                WARN_ONCE(1, "memremap attempted on ram %pa size: %#lx\n",
                                &offset, (unsigned long) size);
                return NULL;
        }
 
-       if (!addr && (flags & MEMREMAP_WT)) {
-               flags &= ~MEMREMAP_WT;
+       if (!addr && (flags & MEMREMAP_WT))
                addr = ioremap_wt(offset, size);
-       }
+
+       if (!addr && (flags & MEMREMAP_WC))
+               addr = ioremap_wc(offset, size);
 
        return addr;
 }
@@ -279,7 +289,8 @@ void *devm_memremap_pages(struct device *dev, struct resource *res,
        align_start = res->start & ~(SECTION_SIZE - 1);
        align_size = ALIGN(res->start + resource_size(res), SECTION_SIZE)
                - align_start;
-       is_ram = region_intersects(align_start, align_size, "System RAM");
+       is_ram = region_intersects(align_start, align_size,
+               IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE);
 
        if (is_ram == REGION_MIXED) {
                WARN_ONCE(1, "%s attempted on mixed region %pr\n",
@@ -389,7 +400,7 @@ struct vmem_altmap *to_vmem_altmap(unsigned long memmap_start)
        /*
         * 'memmap_start' is the virtual address for the first "struct
         * page" in this range of the vmemmap array.  In the case of
-        * CONFIG_SPARSE_VMEMMAP a page_to_pfn conversion is simple
+        * CONFIG_SPARSEMEM_VMEMMAP a page_to_pfn conversion is simple
         * pointer arithmetic, so we can perform this to_vmem_altmap()
         * conversion without concern for the initialization state of
         * the struct page fields.
@@ -398,7 +409,7 @@ struct vmem_altmap *to_vmem_altmap(unsigned long memmap_start)
        struct dev_pagemap *pgmap;
 
        /*
-        * Uncoditionally retrieve a dev_pagemap associated with the
+        * Unconditionally retrieve a dev_pagemap associated with the
         * given physical address, this is only for use in the
         * arch_{add|remove}_memory() for setting up and tearing down
         * the memmap.