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authorDan Brown <dan_brown@ieee.org>2005-04-07 15:22:58 +0100
committerThomas Gleixner <tglx@mtd.linutronix.de>2005-05-23 13:11:44 +0200
commitabc37e6771ec92bb4c531d218ad572afbef6aa21 (patch)
treecc30e91741b76c94380748d5c6c0cb82d31a7e3f
parent7e4a1d3e6abec5464169a29a3d34473a59e2e8b7 (diff)
[MTD] DiskOnChip: Add some comments
Add helpful comment about oobfree so I can't claim two years from now that I don't remember what I was thinking. Signed-off-by: Dan Brown <dan_brown@ieee.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
-rw-r--r--drivers/mtd/nand/diskonchip.c12
1 files changed, 11 insertions, 1 deletions
diff --git a/drivers/mtd/nand/diskonchip.c b/drivers/mtd/nand/diskonchip.c
index 9f33f335a39..fdb5d4ad3d5 100644
--- a/drivers/mtd/nand/diskonchip.c
+++ b/drivers/mtd/nand/diskonchip.c
@@ -16,7 +16,7 @@
*
* Interface to generic NAND code for M-Systems DiskOnChip devices
*
- * $Id: diskonchip.c,v 1.53 2005/04/07 13:39:13 dbrown Exp $
+ * $Id: diskonchip.c,v 1.54 2005/04/07 14:22:55 dbrown Exp $
*/
#include <linux/kernel.h>
@@ -1049,6 +1049,16 @@ static int doc200x_correct_data(struct mtd_info *mtd, u_char *dat, u_char *read_
//u_char mydatabuf[528];
+/* The strange out-of-order .oobfree list below is a (possibly unneeded)
+ * attempt to retain compatibility. It used to read:
+ * .oobfree = { {8, 8} }
+ * Since that leaves two bytes unusable, it was changed. But the following
+ * scheme might affect existing jffs2 installs by moving the cleanmarker:
+ * .oobfree = { {6, 10} }
+ * jffs2 seems to handle the above gracefully, but the current scheme seems
+ * safer. The only problem with it is that any code that parses oobfree must
+ * be able to handle out-of-order segments.
+ */
static struct nand_oobinfo doc200x_oobinfo = {
.useecc = MTD_NANDECC_AUTOPLACE,
.eccbytes = 6,