[PATCH v4 03/11] efi_loader: capsule: add back efi_get_public_key_data()

[AKASHI Takahiro]

The commit 47a25e81d35c ("Revert "efi_capsule: Move signature from DTB to
.rodata"") failed to revert the removal of efi_get_public_key_data().

Add back this function and move it under lib/efi_loader so that other
platforms can utilize it. It is now declared as a weak function so that
it can be replaced with a platform-specific implementation.

Fixes: 47a25e81d35c ("Revert "efi_capsule: Move signature from DTB to
        .rodata"")
Signed-off-by: AKASHI Takahiro <takahiro.aka...@linaro.org>
---
 lib/efi_loader/efi_capsule.c | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/lib/efi_loader/efi_capsule.c b/lib/efi_loader/efi_capsule.c
index b75e4bcba1a9..44f5da61a9be 100644
--- a/lib/efi_loader/efi_capsule.c
+++ b/lib/efi_loader/efi_capsule.c
@@ -11,15 +11,20 @@
 #include <common.h>
 #include <efi_loader.h>
 #include <efi_variable.h>
+#include <env.h>
+#include <fdtdec.h>
 #include <fs.h>
 #include <malloc.h>
 #include <mapmem.h>
 #include <sort.h>
+#include <asm/global_data.h>
 
 #include <crypto/pkcs7.h>
 #include <crypto/pkcs7_parser.h>
 #include <linux/err.h>
 
+DECLARE_GLOBAL_DATA_PTR;
+
 const efi_guid_t efi_guid_capsule_report = EFI_CAPSULE_REPORT_GUID;
 static const efi_guid_t efi_guid_firmware_management_capsule_id =
                EFI_FIRMWARE_MANAGEMENT_CAPSULE_ID_GUID;
@@ -251,6 +256,37 @@ out:
 }
 
 #if defined(CONFIG_EFI_CAPSULE_AUTHENTICATE)
+int __weak efi_get_public_key_data(void **pkey, efi_uintn_t *pkey_len)
+{
+       const void *fdt_blob = gd->fdt_blob;
+       const void *blob;
+       const char *cnode_name = "capsule-key";
+       const char *snode_name = "signature";
+       int sig_node;
+       int len;
+
+       sig_node = fdt_subnode_offset(fdt_blob, 0, snode_name);
+       if (sig_node < 0) {
+               log_err("Unable to get signature node offset\n");
+
+               return -FDT_ERR_NOTFOUND;
+       }
+
+       blob = fdt_getprop(fdt_blob, sig_node, cnode_name, &len);
+
+       if (!blob || len < 0) {
+               log_err("Unable to get capsule-key value\n");
+               *pkey = NULL;
+               *pkey_len = 0;
+
+               return -FDT_ERR_NOTFOUND;
+       }
+
+       *pkey = (void *)blob;
+       *pkey_len = len;
+
+       return 0;
+}
 
 efi_status_t efi_capsule_authenticate(const void *capsule, efi_uintn_t 
capsule_size,
                                      void **image, efi_uintn_t *image_size)
-- 
2.33.0