efi: Add functions for decoding the EFI tables

The EFI stub can pass a table to U-Boot with information about the memory map
Potentially other things will follow. Add a way to access this table.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

diff --git a/lib/efi/Makefile b/lib/efi/Makefile
index 4bc67f01f95319e32e08b3062a95a9f0cd02f761..e32dc14f3d61645a22262d5ba38e1d29feaf5968 100644 (file)
--- a/lib/efi/Makefile
+++ b/lib/efi/Makefile
@@ -5,6 +5,7 @@
 #
 
 obj-$(CONFIG_EFI_APP) += efi_app.o efi.o
+obj-$(CONFIG_EFI_STUB) += efi_info.o
 
 CFLAGS_REMOVE_efi_stub.o := -mregparm=3 \
        $(if $(CONFIG_EFI_STUB_64BIT),-march=i386 -m32)

diff --git a/lib/efi/efi_info.c b/lib/efi/efi_info.c
new file mode 100644 (file)
index 0000000..0cd9a7e
--- /dev/null
+++ b/lib/efi/efi_info.c
@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2015 Google, Inc
+ *
+ * SPDX-License-Identifier:    GPL-2.0+
+ *
+ * Access to the EFI information table
+ */
+
+#include <common.h>
+#include <efi.h>
+#include <errno.h>
+#include <mapmem.h>
+
+int efi_info_get(enum efi_entry_t type, void **datap, int *sizep)
+{
+       struct efi_entry_hdr *entry;
+       struct efi_info_hdr *info;
+       int ret;
+
+       if (!gd->arch.table)
+               return -ENODATA;
+
+       info = map_sysmem(gd->arch.table, 0);
+       if (info->version != EFI_TABLE_VERSION) {
+               ret = -EPROTONOSUPPORT;
+               goto err;
+       }
+
+       entry = (struct efi_entry_hdr *)((ulong)info + info->hdr_size);
+       while (entry->type != EFIET_END) {
+               if (entry->type == type) {
+                       if (entry->addr)
+                               *datap = map_sysmem(entry->addr, entry->size);
+                       else
+                               *datap = entry + 1;
+                       *sizep = entry->size;
+                       return 0;
+               }
+               entry = (struct efi_entry_hdr *)((ulong)entry + entry->link);
+       }
+
+       ret = -ENOENT;
+err:
+       unmap_sysmem(info);
+
+       return ret;
+}