g: add a function to report current board ID mismatch status

Until the Board ID check is moved to RO, it is possible to start an RW
with a mismatching Board ID.

Let's add a function to check for mismatch and report the status.

Also eliminating the unnecessary check for empty header Board ID field
- it is going to match any board ID anyways and fixing a CPRINTF
statement in read_board_id().

BRANCH=cr50
BUG=b:35586335
TEST=verified that empty board ID header does not trigger a mismatch
     on a board with a non-empty INFO1. With the rest of the patches
     applied verified that board ID mismatch is reported properly.

Change-Id: Ie03f8137e494117b7a238e3af72527e0a46369e1
Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/535975
Reviewed-by: Aseda Aboagye <aaboagye@chromium.org>

1 files changed, 16 insertions, 7 deletions

diff --git a/chip/g/board_id.c b/chip/g/board_id.c
index fb3fb8755e..85b84c63ed 100644
--- a/chip/g/board_id.c
+++ b/chip/g/board_id.c
@@ -39,12 +39,6 @@ uint32_t check_board_id_vs_header(const struct board_id *id,
 	header_board_id_mask = SIGNED_HEADER_PADDING ^ h->board_id_type_mask;
 	header_board_id_flags = SIGNED_HEADER_PADDING ^ h->board_id_flags;
 
-	/* Blank header means this is a common image, can run on any device. */
-	if ((header_board_id_type |
-	     header_board_id_mask |
-	     header_board_id_flags) == 0)
-		return 0;
-
 	/*
 	 * Masked bits in header Board ID type must match type and inverse from
 	 * flash.
@@ -92,7 +86,7 @@ int read_board_id(struct board_id *id)
 			 id_p);
 		if (rv != EC_SUCCESS) {
 			CPRINTF("%s: failed to read word %d, error %d\n",
-				i, rv);
+				__func__, i, rv);
 			return rv;
 		}
 		id_p++;
@@ -100,6 +94,21 @@ int read_board_id(struct board_id *id)
 	return EC_SUCCESS;
 }
 
+uint32_t board_id_mismatch(void)
+{
+	struct board_id id;
+	const struct SignedHeader *sh;
+
+	/* Get header of the currently running image. */
+	sh = get_current_image_header();
+
+	/* Get Board ID from INFO1. */
+	if (read_board_id(&id) != EC_SUCCESS)
+		return 1;
+
+	return check_board_id_vs_header(&id, sh);
+}
+
 /**
  * Write board ID into the flash INFO1 space.
  *