ACPI: Export interfaces for ioremapping/iounmapping ACPI registers

Export remapping and unmapping interfaces - acpi_os_map_generic_address()
and acpi_os_unmap_generic_address() - for ACPI generic registers that are
backed by memory mapped I/O (MMIO).

The acpi_os_map_generic_address() and acpi_os_unmap_generic_address()
declarations may more properly belong in include/acpi/acpiosxf.h next to
acpi_os_read_memory() but I believe that would require the ACPI CA making
them an official part of the ACPI CA - OS interface.

ACPI Generic Address Structure (GAS) reference (ACPI's fixed/generic
hardware registers use the GAS format):
ACPI Specification, Revision 4.0, Section 5.2.3.1, "Generic Address
Structure"

Signed-off-by: Myron Stowe <[e-mail]>
Acked-by: Rafael J. Wysocki <[e-mail]>
Signed-off-by: Len Brown <[e-mail]>

drivers/acpi/osl.c

···
 		__acpi_unmap_table(virt, size);
 }
 
-static int acpi_os_map_generic_address(struct acpi_generic_address *gas)
+int acpi_os_map_generic_address(struct acpi_generic_address *gas)
 {
 	u64 addr;
 	void __iomem *virt;
···
 
 	return 0;
 }
+EXPORT_SYMBOL(acpi_os_map_generic_address);
 
-static void acpi_os_unmap_generic_address(struct acpi_generic_address *gas)
+void acpi_os_unmap_generic_address(struct acpi_generic_address *gas)
 {
 	u64 addr;
 	struct acpi_ioremap *map;
···
 
 	acpi_os_map_cleanup(map);
 }
+EXPORT_SYMBOL(acpi_os_unmap_generic_address);
 
 #ifdef ACPI_FUTURE_USAGE
 acpi_status

include/linux/acpi_io.h

···
 
 void __iomem *acpi_os_get_iomem(acpi_physical_address phys, unsigned int size);
 
+int acpi_os_map_generic_address(struct acpi_generic_address *addr);
+void acpi_os_unmap_generic_address(struct acpi_generic_address *addr);
+
 #endif