[MTD] Improve heuristic for detecting wrong-endian RedBoot partition table

[Linux-MTD Mailing List]

Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=7ca353a428ecbaf77b651fbacfcb2f2f6d813879
Commit:     7ca353a428ecbaf77b651fbacfcb2f2f6d813879
Parent:     11192146e57bc8e58865e7d9c2497f66a4f7e6e7
Author:     David Woodhouse <dwmw2 at infradead.org>
AuthorDate: Sat Feb 10 09:58:31 2007 +0000
Committer:  David Woodhouse <dwmw2 at infradead.org>
CommitDate: Sat Feb 10 09:58:31 2007 +0000

    [MTD] Improve heuristic for detecting wrong-endian RedBoot partition table
    
    Also limit the amount we scan to one eraseblock.
    
    Signed-off-by: David Woodhouse <dwmw2 at infradead.org>
---
 drivers/mtd/redboot.c |   13 +++++++++++--
 1 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/redboot.c b/drivers/mtd/redboot.c
index a459ffa..a61351f 100644
--- a/drivers/mtd/redboot.c
+++ b/drivers/mtd/redboot.c
@@ -94,7 +94,16 @@ static int parse_redboot_partitions(struct mtd_info *master,
 			 * (NOTE: this is 'size' not 'data_length'; size is
 			 * the full size of the entry.)
 			 */
-			if (swab32(buf[i].size) == master->erasesize) {
+
+			/* RedBoot can combine the FIS directory and
+			   config partitions into a single eraseblock;
+			   we assume wrong-endian if either the swapped
+			   'size' matches the eraseblock size precisely,
+			   or if the swapped size actually fits in an
+			   eraseblock while the unswapped size doesn't. */
+			if (swab32(buf[i].size) == master->erasesize ||
+			    (buf[i].size > master->erasesize
+			     && swab32(buf[i].size) < master->erasesize)) {
 				int j;
 				/* Update numslots based on actual FIS directory size */
 				numslots = swab32(buf[i].size) / sizeof (struct fis_image_desc);
@@ -122,7 +131,7 @@ static int parse_redboot_partitions(struct mtd_info *master,
 					swab32s(&buf[j].desc_cksum);
 					swab32s(&buf[j].file_cksum);
 				}
-			} else {
+			} else if (buf[i].size < master->erasesize) {
 				/* Update numslots based on actual FIS directory size */
 				numslots = buf[i].size / sizeof(struct fis_image_desc);
 			}