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/mm/ioremap.c b/arch/arm/mm/ioremap.c
index d5350f6..ff0eed2 100644
--- a/arch/arm/mm/ioremap.c
+++ b/arch/arm/mm/ioremap.c
@@ -297,9 +297,10 @@
}
/*
- * Don't allow RAM to be mapped - this causes problems with ARMv6+
+ * Don't allow RAM to be mapped with mismatched attributes - this
+ * causes problems with ARMv6+
*/
- if (WARN_ON(pfn_valid(pfn)))
+ if (WARN_ON(pfn_valid(pfn) && mtype != MT_MEMORY_RW))
return NULL;
area = get_vm_area_caller(size, VM_IOREMAP, caller);
@@ -418,6 +419,13 @@
__builtin_return_address(0));
}
+void *arch_memremap_wb(phys_addr_t phys_addr, size_t size)
+{
+ return (__force void *)arch_ioremap_caller(phys_addr, size,
+ MT_MEMORY_RW,
+ __builtin_return_address(0));
+}
+
void __iounmap(volatile void __iomem *io_addr)
{
void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);