ARM: memremap: implement arch_memremap_wb()
The generic memremap() falls back to using ioremap_cache() to create
MEMREMAP_WB mappings if the requested region is not already covered
by the linear mapping, unless the architecture provides an implementation
of arch_memremap_wb().
Since ioremap_cache() is not appropriate on ARM to map memory with the
same attributes used for the linear mapping, implement arch_memremap_wb()
which does exactly that. Also, relax the WARN() check to allow MT_MEMORY_RW
mappings of pfn_valid() pages.
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h
index fb94de2..781ef5f 100644
--- a/arch/arm/include/asm/io.h
+++ b/arch/arm/include/asm/io.h
@@ -392,6 +392,9 @@
#define ioremap ioremap
#define ioremap_nocache ioremap
+/*
+ * Do not use ioremap_cache for mapping memory. Use memremap instead.
+ */
void __iomem *ioremap_cache(resource_size_t res_cookie, size_t size);
#define ioremap_cache ioremap_cache
@@ -408,6 +411,9 @@
void iounmap(volatile void __iomem *iomem_cookie);
#define iounmap iounmap
+void *arch_memremap_wb(phys_addr_t phys_addr, size_t size);
+#define arch_memremap_wb arch_memremap_wb
+
/*
* io{read,write}{16,32}be() macros
*/