[PATCH RFC u-boot-mvebu 15/59] tools: kwboot: Fix parsing UART image without data checksum

[Pali Rohár]

The 32-bit data checksum in UART image is not checked by the BootROM and
also Marvell tools do not generate it.

So if data checksum stored in UART image does not match calculated checksum
from the image then treat those checksum bytes as part of the executable
image code (and not as the checksum) and for compatibility with the rest of
the code manually insert data checksum into the in-memory image after the
executable code, without overwriting it.

This should allow to boot UART images generated by Marvell tools.

Signed-off-by: Pali Rohár <pali at kernel.org>
---
 tools/kwboot.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/tools/kwboot.c b/tools/kwboot.c
index 7a7dd5bf3d7b..da840864b565 100644
--- a/tools/kwboot.c
+++ b/tools/kwboot.c
@@ -1990,8 +1990,18 @@ kwboot_img_patch(void *img, size_t *size, int baudrate)
 	    *size < le32_to_cpu(hdr->srcaddr) + le32_to_cpu(hdr->blocksize))
 		goto err;
 
-	if (kwboot_img_csum32(img) != *kwboot_img_csum32_ptr(img))
-		goto err;
+	/*
+	 * The 32-bit data checksum is optional for UART image. If it is not
+	 * present (checksum detected as invalid) then grow data part of the
+	 * image for the checksum, so it can be inserted there.
+	 */
+	if (kwboot_img_csum32(img) != *kwboot_img_csum32_ptr(img)) {
+		if (hdr->blockid != IBR_HDR_UART_ID) {
+			fprintf(stderr, "Image has invalid data checksum\n");
+			goto err;
+		}
+		kwboot_img_grow_data_right(img, size, sizeof(uint32_t));
+	}
 
 	is_secure = kwboot_img_is_secure(img);
 
@@ -2256,6 +2266,7 @@ main(int argc, char **argv)
 				 KWBOOT_XM_BLKSZ +
 				 sizeof(kwboot_baud_code) +
 				 sizeof(kwboot_baud_code_data_jump) +
+				 sizeof(uint32_t) +
 				 KWBOOT_XM_BLKSZ;
 
 	if (imgpath) {
-- 
2.20.1