chip/g: Add support for deprecated RO version_struct

Master chip/g FW still needs to support deprecated RO, so re-add support
for the old version_struct. This CL can be reverted once we no longer
need to support deprecated RO on master.

BUG=chromium:698881,chromium:698882
TEST=Flash old FW (f51fdf2) to RW_B slot and updated FW to RW_A. Verify
cr50 boots into RW_A, and "version" on the console prints RW_B version,
not "Error".
BRANCH=None

Signed-off-by: Shawn Nematbakhsh <shawnn@chromium.org>
Change-Id: I3c255afcd12da5694ca128960de8d2abe41686dc
Reviewed-on: https://chromium-review.googlesource.com/450860
Commit-Ready: Shawn N <shawnn@chromium.org>
Tested-by: Shawn N <shawnn@chromium.org>
Reviewed-by: Vadim Bendebury <vbendeb@chromium.org>

1 files changed, 37 insertions, 7 deletions

diff --git a/chip/g/system.c b/chip/g/system.c
index 0e33bcef00..1dbf3882a4 100644
--- a/chip/g/system.c
+++ b/chip/g/system.c
@@ -259,6 +259,19 @@ enum system_image_copy_t system_get_ro_image_copy(void)
 }
 
 /*
+ * TODO(crbug.com/698882): Remove support for version_struct_deprecated once
+ * we no longer care about supporting legacy RO.
+ */
+struct version_struct_deprecated {
+	uint32_t cookie1;
+	char version[32];
+	uint32_t cookie2;
+};
+
+#define CROS_EC_IMAGE_DATA_COOKIE1_DEPRECATED 0xce112233
+#define CROS_EC_IMAGE_DATA_COOKIE2_DEPRECATED 0xce445566
+
+/*
  * The RW images contain version strings. The RO images don't, so we'll make
  * some here.
  */
@@ -268,6 +281,9 @@ static char vers_str[MAX_RO_VER_LEN];
 const char *system_get_version(enum system_image_copy_t copy)
 {
 	const struct image_data *data;
+	const struct version_struct_deprecated *data_deprecated;
+	const char *version;
+
 	const struct SignedHeader *h;
 	enum system_image_copy_t this_copy;
 	uintptr_t vaddr, delta;
@@ -314,21 +330,35 @@ const char *system_get_version(enum system_image_copy_t copy)
 		if (vaddr == INVALID_ADDR)
 			break;
 		h = (const struct SignedHeader *)vaddr;
+		/* Corrupted header's magic is set to zero. */
+		if (!h->magic)
+			break;
+
 		vaddr += delta;
 		data = (const struct image_data *)vaddr;
+		data_deprecated = (const struct version_struct_deprecated *)
+				  vaddr;
 
 		/*
 		 * Make sure the version struct cookies match before returning
 		 * the version string.
 		 */
 		if (data->cookie1 == current_image_data.cookie1 &&
-		    data->cookie2 == current_image_data.cookie2 &&
-		    h->magic) { /* Corrupted header's magic is set to zero. */
-			snprintf(vers_str, sizeof(vers_str), "%d.%d.%d/%s",
-				 h->epoch_, h->major_, h->minor_,
-				 data->version);
-			return vers_str;
-		}
+		    data->cookie2 == current_image_data.cookie2)
+			version = data->version;
+		/* Check for old / deprecated structure. */
+		else if (data_deprecated->cookie1 ==
+			 CROS_EC_IMAGE_DATA_COOKIE1_DEPRECATED &&
+			 data_deprecated->cookie2 ==
+			 CROS_EC_IMAGE_DATA_COOKIE2_DEPRECATED)
+			version = data_deprecated->version;
+		else
+			break;
+
+		snprintf(vers_str, sizeof(vers_str), "%d.%d.%d/%s",
+			 h->epoch_, h->major_, h->minor_, version);
+		return vers_str;
+
 	default:
 		break;
 	}