firmware-utils: bcm4908img: extract bootfs without padding

JFFS2 bootfs partition in a BCM4908 image usually includes some padding.
For flashing it individually (writing to designed MTD partition) we want
just JFFS2 data.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>

diff --git a/tools/firmware-utils/src/bcm4908img.c b/tools/firmware-utils/src/bcm4908img.c
index b82303bf6d9cf848beefe6e7d248a80b9822bf7d..d97e54e0f6b4924cb1d7098c21da8632fc5d0ce8 100644 (file)
--- a/tools/firmware-utils/src/bcm4908img.c
+++ b/tools/firmware-utils/src/bcm4908img.c
@@ -6,6 +6,7 @@
 #include <byteswap.h>
 #include <endian.h>
 #include <errno.h>
+#include <stdbool.h>
 #include <stddef.h>
 #include <stdint.h>
 #include <stdio.h>
@@ -81,6 +82,7 @@ struct bcm4908img_info {
        size_t file_size;
        size_t cferom_offset;
        size_t bootfs_offset;
+       size_t padding_offset;
        size_t rootfs_offset;
        uint32_t crc32;                 /* Calculated checksum */
        struct bcm4908img_tail tail;
@@ -247,6 +249,19 @@ struct chk_header {
        char board_id[0];
 };
 
+static bool bcm4908img_is_all_ff(const void *buf, size_t length)
+{
+       const uint8_t *in = buf;
+       int i;
+
+       for (i = 0; i < length; i++) {
+               if (in[i] != 0xff)
+                       return false;
+       }
+
+       return true;
+}
+
 static int bcm4908img_parse(FILE *fp, struct bcm4908img_info *info) {
        struct bcm4908img_tail *tail = &info->tail;
        struct chk_header *chk;
@@ -304,7 +319,7 @@ static int bcm4908img_parse(FILE *fp, struct bcm4908img_info *info) {
        for (info->rootfs_offset = info->bootfs_offset;
             info->rootfs_offset < info->file_size;
             info->rootfs_offset += 0x20000) {
-               uint32_t magic;
+               uint32_t *magic = (uint32_t *)&buf[0];
 
                if (fseek(fp, info->rootfs_offset, SEEK_SET)) {
                        err = -errno;
@@ -312,13 +327,17 @@ static int bcm4908img_parse(FILE *fp, struct bcm4908img_info *info) {
                        return err;
                }
 
-               bytes = fread(&magic, 1, sizeof(magic), fp);
-               if (bytes != sizeof(magic)) {
-                       fprintf(stderr, "Failed to read %zu bytes\n", sizeof(magic));
+               length = info->padding_offset ? sizeof(*magic) : 256;
+               bytes = fread(buf, 1, length, fp);
+               if (bytes != length) {
+                       fprintf(stderr, "Failed to read %zu bytes\n", length);
                        return -EIO;
                }
 
-               if (be32_to_cpu(magic) == UBI_EC_HDR_MAGIC)
+               if (!info->padding_offset && bcm4908img_is_all_ff(buf, length))
+                       info->padding_offset = info->rootfs_offset;
+
+               if (be32_to_cpu(*magic) == UBI_EC_HDR_MAGIC)
                        break;
        }
        if (info->rootfs_offset >= info->file_size) {
@@ -394,6 +413,8 @@ static int bcm4908img_info(int argc, char **argv) {
        if (info.bootfs_offset != info.cferom_offset)
                printf("cferom offset:\t%zu\n", info.cferom_offset);
        printf("bootfs offset:\t0x%zx\n", info.bootfs_offset);
+       if (info.padding_offset)
+               printf("padding offset:\t0x%zx\n", info.padding_offset);
        printf("rootfs offset:\t0x%zx\n", info.rootfs_offset);
        printf("Checksum:\t0x%08x\n", info.crc32);
 
@@ -589,7 +610,7 @@ static int bcm4908img_extract(int argc, char **argv) {
                }
        } else if (!strcmp(type, "bootfs")) {
                offset = info.bootfs_offset;
-               length = info.rootfs_offset - offset;
+               length = (info.padding_offset ? info.padding_offset : info.rootfs_offset) - offset;
        } else if (!strcmp(type, "rootfs")) {
                offset = info.rootfs_offset;
                length = info.file_size - offset - sizeof(struct bcm4908img_tail);