nandwrite: always check the first erase block

Current code does not check the first erase block when mtdoffset is not erase
block aligned. Fix this.

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 14 insertions, 2 deletions

diff --git a/miscutils/nandwrite.c b/miscutils/nandwrite.c
index 8df0fdc81..f42242687 100644
--- a/miscutils/nandwrite.c
+++ b/miscutils/nandwrite.c
@@ -52,7 +52,7 @@ int nandwrite_main(int argc UNUSED_PARAM, char **argv)
         unsigned opts;
         int fd;
         ssize_t cnt;
-        unsigned mtdoffset, meminfo_writesize;
+        unsigned mtdoffset, meminfo_writesize, blockstart;
         struct mtd_info_user meminfo;
         unsigned char *filebuf;
         const char *opt_s = "0";
@@ -83,9 +83,21 @@ int nandwrite_main(int argc UNUSED_PARAM, char **argv)
 
         filebuf = xmalloc(meminfo_writesize);
 
+        blockstart = mtdoffset & ~(meminfo.erasesize - 1);
+        if (blockstart != mtdoffset) {
+                unsigned tmp;
+                /* mtdoffset is in the middle of an erase block, verify that
+                 * this block is OK. Advance mtdoffset only if this block is
+                 * bad.
+                 */
+                tmp = next_good_eraseblock(fd, &meminfo, blockstart);
+                if (tmp != blockstart) /* bad block(s), advance mtdoffset */
+                        mtdoffset = tmp;
+        }
+
         cnt = -1;
         while (mtdoffset < meminfo.size) {
-                unsigned blockstart = mtdoffset & ~(meminfo.erasesize - 1);
+                blockstart = mtdoffset & ~(meminfo.erasesize - 1);
                 if (blockstart == mtdoffset) {
                         /* starting a new eraseblock */
                         mtdoffset = next_good_eraseblock(fd, &meminfo, blockstart);