nand_util: treat WITH_YAFFS_OOB as a mode

When specified in the flags argument of nand_write, WITH_YAFFS_OOB causes an
operation which is mutually exclusive with the 'usual' way of writing.

Add a check that client code does not specify WITH_YAFFS_OOB along with any
other flags and add a comment indicating that the WITH_YAFFS_OOB flag should
not be mixed with other flags.

Signed-off-by: Ben Gardiner <bengardiner@nanometrics.ca>
CC: Scott Wood <scottwood@freescale.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>

drivers/mtd/nand/nand_util.c

@@ -461,6 +461,9 @@ int nand_write_skip_bad(nand_info_t *nand, loff_t offset, size_t *length,
 
 #ifdef CONFIG_CMD_NAND_YAFFS
 	if (flags & WITH_YAFFS_OOB) {
+		if (flags & ~WITH_YAFFS_OOB)
+			return -EINVAL;
+
 		int pages;
 		pages = nand->erasesize / nand->writesize;
 		blocksize = (pages * nand->oobsize) + nand->erasesize;

include/nand.h

@@ -115,7 +115,9 @@ typedef struct nand_erase_options nand_erase_options_t;
 int nand_read_skip_bad(nand_info_t *nand, loff_t offset, size_t *length,
 		       u_char *buffer);
 
-#define WITH_YAFFS_OOB	(1 << 0) /* whether write with yaffs format */
+#define WITH_YAFFS_OOB	(1 << 0) /* whether write with yaffs format. This flag
+				  * is a 'mode' meaning it cannot be mixed with
+				  * other flags */
 
 int nand_write_skip_bad(nand_info_t *nand, loff_t offset, size_t *length,
 			u_char *buffer, int flags);