tools: kwbimage: Refactor kwbimage header size determination

Add functions kwbheader_size() and kwbheader_size_for_csum().

Refactor code determining header size to use these functions.

Refactor header checksum determining function.

Remove stuff that is not needed anymore.

This simplifies the code a little and fixes one instance of validating
header size meant for checksum instead of whole header size.

Signed-off-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Stefan Roese <sr@denx.de>

tools/kwbimage.c

@@ -280,14 +280,6 @@ static uint8_t image_checksum8(void *start, uint32_t len)
 	return csum;
 }
 
-size_t kwbimage_header_size(unsigned char *ptr)
-{
-	if (kwbimage_version((void *)ptr) == 0)
-		return sizeof(struct main_hdr_v0);
-	else
-		return KWBHEADER_V1_SIZE((struct main_hdr_v1 *)ptr);
-}
-
 /*
  * Verify checksum over a complete header that includes the checksum field.
  * Return 1 when OK, otherwise 0.
@@ -298,7 +290,7 @@ static int main_hdr_checksum_ok(void *hdr)
 	struct main_hdr_v0 *main_hdr = (struct main_hdr_v0 *)hdr;
 	uint8_t checksum;
 
-	checksum = image_checksum8(hdr, kwbimage_header_size(hdr));
+	checksum = image_checksum8(hdr, kwbheader_size_for_csum(hdr));
 	/* Calculated checksum includes the header checksum field. Compensate
 	 * for that.
 	 */
@@ -1649,8 +1641,8 @@ static int kwbimage_check_image_types(uint8_t type)
 static int kwbimage_verify_header(unsigned char *ptr, int image_size,
 				  struct image_tool_params *params)
 {
-	uint8_t checksum;
+	size_t header_size = kwbheader_size(ptr);
-	size_t header_size = kwbimage_header_size(ptr);
+	uint8_t csum;
 
 	if (header_size > image_size)
 		return -FDT_ERR_BADSTRUCTURE;
@@ -1663,17 +1655,10 @@ static int kwbimage_verify_header(unsigned char *ptr, int image_size,
 		struct main_hdr_v0 *mhdr = (struct main_hdr_v0 *)ptr;
 
 		if (mhdr->ext & 0x1) {
-			struct ext_hdr_v0 *ext_hdr;
+			struct ext_hdr_v0 *ext_hdr = (void *)(mhdr + 1);
 
-			if (header_size + sizeof(*ext_hdr) > image_size)
+			csum = image_checksum8(ext_hdr, sizeof(*ext_hdr) - 1);
-				return -FDT_ERR_BADSTRUCTURE;
+			if (csum != ext_hdr->checksum)
-
-			ext_hdr = (struct ext_hdr_v0 *)
-				(ptr + sizeof(struct main_hdr_v0));
-			checksum = image_checksum8(ext_hdr,
-						   sizeof(struct ext_hdr_v0)
-						   - sizeof(uint8_t));
-			if (checksum != ext_hdr->checksum)
 				return -FDT_ERR_BADSTRUCTURE;
 		}
 	} else if (kwbimage_version(ptr) == 1) {
@@ -1832,7 +1817,7 @@ static int kwbimage_generate(struct image_tool_params *params,
 static int kwbimage_extract_subimage(void *ptr, struct image_tool_params *params)
 {
 	struct main_hdr_v1 *mhdr = (struct main_hdr_v1 *)ptr;
-	size_t header_size = kwbimage_header_size(ptr);
+	size_t header_size = kwbheader_size(ptr);
 	struct opt_hdr_v1 *ohdr;
 	int idx = params->pflag;
 	int cur_idx = 0;

tools/kwbimage.h

@@ -69,11 +69,6 @@ struct ext_hdr_v0 {
 	uint8_t               checksum;
 } __packed;
 
-struct kwb_header {
-	struct main_hdr_v0	kwb_hdr;
-	struct ext_hdr_v0	kwb_exthdr;
-} __packed;
-
 /* Structure of the main header, version 1 (Armada 370/38x/XP) */
 struct main_hdr_v1 {
 	uint8_t  blockid;               /* 0x0       */
@@ -195,13 +190,6 @@ struct register_set_hdr_v1 {
 #define OPT_HDR_V1_BINARY_TYPE   0x2
 #define OPT_HDR_V1_REGISTER_TYPE 0x3
 
-#define KWBHEADER_V0_SIZE(hdr) \
-	(((hdr)->ext & 0x1) ? sizeof(struct kwb_header) : \
-			      sizeof(struct main_hdr_v0))
-
-#define KWBHEADER_V1_SIZE(hdr) \
-	(((hdr)->headersz_msb << 16) | le16_to_cpu((hdr)->headersz_lsb))
-
 enum kwbimage_cmd {
 	CMD_INVALID,
 	CMD_BOOT_FROM,
@@ -235,6 +223,29 @@ static inline unsigned int kwbimage_version(const void *header)
 	return ptr[8];
 }
 
+static inline size_t kwbheader_size(const void *header)
+{
+	if (kwbimage_version(header) == 0) {
+		const struct main_hdr_v0 *hdr = header;
+
+		return sizeof(*hdr) +
+		       (hdr->ext & 0x1) ? sizeof(struct ext_hdr_v0) : 0;
+	} else {
+		const struct main_hdr_v1 *hdr = header;
+
+		return (hdr->headersz_msb << 16) |
+		       le16_to_cpu(hdr->headersz_lsb);
+	}
+}
+
+static inline size_t kwbheader_size_for_csum(const void *header)
+{
+	if (kwbimage_version(header) == 0)
+		return sizeof(struct main_hdr_v0);
+	else
+		return kwbheader_size(header);
+}
+
 static inline uint32_t opt_hdr_v1_size(const struct opt_hdr_v1 *ohdr)
 {
 	return (ohdr->headersz_msb << 16) | le16_to_cpu(ohdr->headersz_lsb);

tools/kwboot.c

@@ -583,10 +583,7 @@ kwboot_xmodem(int tty, const void *_img, size_t size)
 	int rc, pnum;
 	size_t hdrsz;
 
-	if (kwbimage_version(img) == 0)
+	hdrsz = kwbheader_size(img);
-		hdrsz = KWBHEADER_V0_SIZE((struct main_hdr_v0 *)img);
-	else
-		hdrsz = KWBHEADER_V1_SIZE((struct main_hdr_v1 *)img);
 
 	kwboot_printv("Waiting 2s and flushing tty\n");
 	sleep(2); /* flush isn't effective without it */
@@ -746,9 +743,13 @@ out:
 }
 
 static uint8_t
-kwboot_img_csum8(void *_data, size_t size)
+kwboot_hdr_csum8(const void *hdr)
 {
-	uint8_t *data = _data, csum;
+	const uint8_t *data = hdr;
+	uint8_t csum;
+	size_t size;
+
+	size = kwbheader_size_for_csum(hdr);
 
 	for (csum = 0; size-- > 0; data++)
 		csum += *data;
@@ -794,17 +795,14 @@ kwboot_img_patch_hdr(void *img, size_t size)
 		goto out;
 	}
 
-	if (image_ver == 0)
+	hdrsz = kwbheader_size(hdr);
-		hdrsz = sizeof(*hdr);
-	else
-		hdrsz = KWBHEADER_V1_SIZE(hdr);
 
 	if (size < hdrsz) {
 		errno = EINVAL;
 		goto out;
 	}
 
-	csum = kwboot_img_csum8(hdr, hdrsz) - hdr->checksum;
+	csum = kwboot_hdr_csum8(hdr) - hdr->checksum;
 	if (csum != hdr->checksum) {
 		errno = EINVAL;
 		goto out;
@@ -860,7 +858,7 @@ kwboot_img_patch_hdr(void *img, size_t size)
 		hdr->blockid = IBR_HDR_UART_ID;
 	}
 
-	hdr->checksum = kwboot_img_csum8(hdr, hdrsz) - csum;
+	hdr->checksum = kwboot_hdr_csum8(hdr) - csum;
 
 	rc = 0;
 out: