[U-Boot] [PATCH] nand: adjust erase/read/write partition/chip size for bad blocks

[Harvey Chapman]

From: Harvey Chapman <hchapman at 3gfp.com>

Adjust the sizes calculated for whole partition/chip operations by
removing the size of bad blocks so we don't try to erase/read/write
past a partition/chip boundary.

Signed-off-by: Harvey Chapman <hchapman at 3gfp.com>
---
 common/cmd_nand.c |   51 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)

diff --git a/common/cmd_nand.c b/common/cmd_nand.c
index 495610c..657ea23 100644
--- a/common/cmd_nand.c
+++ b/common/cmd_nand.c
@@ -428,6 +428,32 @@ static int raw_access(nand_info_t *nand, ulong addr, loff_t off, ulong count,
 	return ret;
 }
 
+static int adjust_size_for_badblocks(loff_t *size, loff_t offset, int dev) {
+	/* We grab the nand info object here fresh because this is usually
+	 * called after arg_off_size() which can change the value of dev.
+	 */
+	nand_info_t *nand = &nand_info[dev];
+	loff_t original_size = *size;
+	loff_t maxoffset = offset + *size;
+	int badblocks = 0;
+
+	/* count badblocks in NAND from offset to offset + size */
+	for (; offset < maxoffset; offset += nand->erasesize)
+		if (nand_block_isbad(nand, offset)) {
+			badblocks++;
+		}
+	/* adjust size if any bad blocks found */
+	if (badblocks) {
+		*size -= badblocks * nand->erasesize;
+		printf("size adjusted to 0x%llx (%d bad blocks)\n",
+		       (unsigned long long)*size, badblocks);
+	}
+	/* return size adjusted as a positive value so callers
+	 * can use the return code to determine if anything happened
+	 */
+	return (original_size - *size);
+}
+
 static int do_nand(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
 	int i, ret = 0;
@@ -524,6 +550,7 @@ static int do_nand(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 		int scrub = !strncmp(cmd, "scrub", 5);
 		int spread = 0;
 		int args = 2;
+		int adjust_size = 0;
 		const char *scrub_warn =
 			"Warning: "
 			"scrub option will erase all factory set bad blocks!\n"
@@ -540,8 +567,10 @@ static int do_nand(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 				spread = 1;
 			} else if (!strcmp(&cmd[5], ".part")) {
 				args = 1;
+				adjust_size = 1;
 			} else if (!strcmp(&cmd[5], ".chip")) {
 				args = 0;
+				adjust_size = 1;
 			} else {
 				goto usage;
 			}
@@ -560,6 +589,15 @@ static int do_nand(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 		if (arg_off_size(argc - o, argv + o, &dev, &off, &size) != 0)
 			return 1;
 
+		/* The size for erase.part and erase.chip has been calculated
+		 * for us as the remainder of the chip/partition from offset.
+		 * Adjust down for bad blocks, if necessary, so we don't
+		 * erase past the end of the chip/partition by accident.
+		 */
+		if (adjust_size && !scrub) {
+			adjust_size_for_badblocks(&size, off, dev);
+		}
+
 		nand = &nand_info[dev];
 
 		memset(&opts, 0, sizeof(opts));
@@ -644,6 +682,19 @@ static int do_nand(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 						&off, &size) != 0)
 				return 1;
 
+			/* If no size was given, it has been calculated for us as
+			 * the remainder of the chip/partition from offset. Adjust
+			 * down for bad blocks, if necessary, so we don't
+			 * read/write past the end of the partition by accident.
+			 *
+			 * nand read addr part size     "size" is arg 5
+			 */
+			if (argc < 5) {
+				/* Don't try to use rwsize here, it's not the
+				 * right type
+				 */
+				adjust_size_for_badblocks(&size, off, dev);
+			}
 			rwsize = size;
 		}
 
-- 
1.7.10.4