efi: x86: make efi_lookup_mapped_addr() a common function

efi_lookup_mapped_addr() is a handy utility for other platforms than
x86. Move it from arch/x86 to drivers/firmware. Add memmap pointer
to global efi structure, and initialise it on x86.

Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>

1 files changed, 32 insertions, 0 deletions

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index e1010d450b65..2e2fbdec0845 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -150,6 +150,38 @@ err_put:
 subsys_initcall(efisubsys_init);
 
 
+/*
+ * We can't ioremap data in EFI boot services RAM, because we've already mapped
+ * it as RAM.  So, look it up in the existing EFI memory map instead.  Only
+ * callable after efi_enter_virtual_mode and before efi_free_boot_services.
+ */
+void __iomem *efi_lookup_mapped_addr(u64 phys_addr)
+{
+        struct efi_memory_map *map;
+        void *p;
+        map = efi.memmap;
+        if (!map)
+                return NULL;
+        if (WARN_ON(!map->map))
+                return NULL;
+        for (p = map->map; p < map->map_end; p += map->desc_size) {
+                efi_memory_desc_t *md = p;
+                u64 size = md->num_pages << EFI_PAGE_SHIFT;
+                u64 end = md->phys_addr + size;
+                if (!(md->attribute & EFI_MEMORY_RUNTIME) &&
+                    md->type != EFI_BOOT_SERVICES_CODE &&
+                    md->type != EFI_BOOT_SERVICES_DATA)
+                        continue;
+                if (!md->virt_addr)
+                        continue;
+                if (phys_addr >= md->phys_addr && phys_addr < end) {
+                        phys_addr += md->virt_addr - md->phys_addr;
+                        return (__force void __iomem *)(unsigned long)phys_addr;
+                }
+        }
+        return NULL;
+}
+
 static __initdata efi_config_table_type_t common_tables[] = {
         {ACPI_20_TABLE_GUID, "ACPI 2.0", &efi.acpi20},
         {ACPI_TABLE_GUID, "ACPI", &efi.acpi},