ACPI: fix acpi_os_ioremap for arm64

The acpi_os_ioremap() function may be used to map normal RAM or IO
regions. The current implementation simply uses ioremap_cache(). This
will work for some architectures, but arm64 ioremap_cache() cannot be
used to map IO regions which don't support caching. So for arm64, use
ioremap() for non-RAM regions.

CC: Rafael J Wysocki <rjw@rjwysocki.net>
CC: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Robert Richter <rrichter@cavium.com>
Tested-by: Timur Tabi <timur@codeaurora.org>
Acked-by: Robert Richter <rrichter@cavium.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Grant Likely <grant.likely@linaro.org>
Signed-off-by: Mark Salter <msalter@redhat.com>
Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

arch/arm64/include/asm/acpi.h

@@ -12,8 +12,21 @@
 #ifndef _ASM_ACPI_H
 #define _ASM_ACPI_H
 
+#include <linux/mm.h>
+
 /* Basic configuration for ACPI */
 #ifdef	CONFIG_ACPI
+/* ACPI table mapping after acpi_gbl_permanent_mmap is set */
+static inline void __iomem *acpi_os_ioremap(acpi_physical_address phys,
+					    acpi_size size)
+{
+	if (!page_is_ram(phys >> PAGE_SHIFT))
+		return ioremap(phys, size);
+
+	return ioremap_cache(phys, size);
+}
+#define acpi_os_ioremap acpi_os_ioremap
+
 #define acpi_strict 1	/* No out-of-spec workarounds on ARM64 */
 extern int acpi_disabled;
 extern int acpi_noirq;

include/acpi/acpi_io.h

@@ -3,11 +3,15 @@
 
 #include <linux/io.h>
 
+#include <asm/acpi.h>
+
+#ifndef acpi_os_ioremap
 static inline void __iomem *acpi_os_ioremap(acpi_physical_address phys,
 					    acpi_size size)
 {
        return ioremap_cache(phys, size);
 }
+#endif
 
 void __iomem *__init_refok
 acpi_os_map_iomem(acpi_physical_address phys, acpi_size size);