[PATCH v2 2/4] nanddump: add options --bb=skipbad and padbad

[Richard Genoud]

In mtd-utils, the bad block options changed in favor of
--bb=[skipbad|padbad|dumpbad] and omitbad has been removed.

This patch add the --bb=skipbad and padbad methods to busybox' nanddump.
padbad is the current default behaviour.
The difference between skipbad and omitbad is this one:
On a 16K block NAND, if the 1st block of mtd0 is bad, we'll have:
nanddump  -b -l 16384 /dev/mtd0 | wc -c
0
nanddump  --bb=skipbad -l 16384 /dev/mtd0 | wc -c
16384 <- data from 1st good block

Signed-off-by: Richard Genoud <richard.genoud at gmail.com>
---
 miscutils/nandwrite.c | 65 ++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 56 insertions(+), 9 deletions(-)

diff --git a/miscutils/nandwrite.c b/miscutils/nandwrite.c
index 8c4da802f6b3..ec133bd55071 100644
--- a/miscutils/nandwrite.c
+++ b/miscutils/nandwrite.c
@@ -36,7 +36,7 @@
 //usage:     "\n	-s ADDR	Start address"
 
 //usage:#define nanddump_trivial_usage
-//usage:	"[-o] [-b] [-s ADDR] [-l LEN] [-f FILE] MTD_DEVICE"
+//usage:	"[-o] [-b|--bb=padbad|skipbad] [-s ADDR] [-l LEN] [-f FILE] MTD_DEVICE"
 //usage:#define nanddump_full_usage "\n\n"
 //usage:	"Dump MTD_DEVICE\n"
 //usage:     "\n	-o	Dump oob data"
@@ -44,6 +44,12 @@
 //usage:     "\n	-s ADDR	Start address"
 //usage:     "\n	-l LEN	Length"
 //usage:     "\n	-f FILE	Dump to file ('-' for stdout)"
+//usage:     "\n	--bb=METHOD, where METHOD can be `skipbad', `padbad':"
+//usage:     "\n	    skipbad: dump good data, completely skipping any bad blocks"
+//usage:     "\n	    padbad: dump flash data, substituting 0xFF for any bad blocks (default)"
+//usage:     "\n	The difference between omit and skip bad block is that in the omit"
+//usage:     "\n	case, the length of the bad block is counted as part of the total"
+//usage:     "\n	dump length, and in the skip case, it's not."
 
 #include "libbb.h"
 #include <mtd/mtd-user.h>
@@ -57,6 +63,11 @@
 #define OPT_b  (1 << 2)
 #define OPT_f  (1 << 3)
 #define OPT_l  (1 << 4)
+#define OPT_bb (1 << 5) /* must be the last one in the list */
+
+#define BB_PADBAD (1 << 0)
+#define BB_SKIPBAD (1 << 1)
+#define BB_OMITBAD (1 << 2)
 
 /* helper for writing out 0xff for bad blocks pad */
 static void dump_bad(struct mtd_info_user *meminfo, unsigned len, int oob)
@@ -102,6 +113,7 @@ int nandwrite_main(int argc UNUSED_PARAM, char **argv)
 	/* Buffer for OOB data */
 	unsigned char *oobbuf;
 	unsigned opts;
+	unsigned bb_method = BB_PADBAD;
 	int fd;
 	ssize_t cnt;
 	unsigned mtdoffset, meminfo_writesize, blockstart, limit;
@@ -109,11 +121,14 @@ int nandwrite_main(int argc UNUSED_PARAM, char **argv)
 	struct mtd_info_user meminfo;
 	struct mtd_oob_buf oob;
 	unsigned char *filebuf;
-	const char *opt_s = "0", *opt_f = "-", *opt_l;
+	const char *opt_s = "0", *opt_f = "-", *opt_l, *opt_bb;
+	static const char nanddump_longopts[] ALIGN1 =
+		"bb\0" Required_argument "\xff"; /* no short equivalent */
 
 	if (IS_NANDDUMP) {
 		opt_complementary = "=1";
-		opts = getopt32(argv, "os:bf:l:", &opt_s, &opt_f, &opt_l);
+		applet_long_options = nanddump_longopts;
+		opts = getopt32(argv, "os:bf:l:", &opt_s, &opt_f, &opt_l, &opt_bb);
 	} else { /* nandwrite */
 		opt_complementary = "-1:?2";
 		opts = getopt32(argv, "ps:", &opt_s);
@@ -138,6 +153,20 @@ int nandwrite_main(int argc UNUSED_PARAM, char **argv)
 		if (length < meminfo.size - mtdoffset)
 			end_addr = mtdoffset + length;
 	}
+	if (IS_NANDDUMP) {
+	       if ((opts & OPT_b) && (opts & OPT_bb))
+		       bb_show_usage();
+	       if (opts & OPT_b)
+		       bb_method = BB_OMITBAD;
+	       if (opts & OPT_bb) {
+		       if (!strcmp("skipbad", opt_bb))
+			       bb_method = BB_SKIPBAD;
+		       else if (!strcmp("padbad", opt_bb))
+			       bb_method = BB_PADBAD;
+		       else
+			       bb_show_usage();
+	       }
+	}
 
 	/* Pull it into a CPU register (hopefully) - smaller code that way */
 	meminfo_writesize = meminfo.writesize;
@@ -162,9 +191,16 @@ int nandwrite_main(int argc UNUSED_PARAM, char **argv)
 		tmp = next_good_eraseblock(fd, &meminfo, blockstart);
 		if (tmp != blockstart) {
 			/* bad block(s), advance mtdoffset */
-			if (IS_NANDDUMP && !(opts & OPT_b)) {
-				int bad_len = MIN(tmp, end_addr) - mtdoffset;
-				dump_bad(&meminfo, bad_len, opts & OPT_o);
+			if (IS_NANDDUMP) {
+				if (bb_method == BB_PADBAD) {
+					int bad_len = MIN(tmp, end_addr) - mtdoffset;
+					dump_bad(&meminfo, bad_len, opts & OPT_o);
+				}
+				/* with option skipbad, increase the total length */
+				if (bb_method == BB_SKIPBAD) {
+					end_addr += (tmp - blockstart);
+				}
+				/* omitbad: do nothing */
 			}
 			mtdoffset = tmp;
 		}
@@ -182,9 +218,20 @@ int nandwrite_main(int argc UNUSED_PARAM, char **argv)
 			mtdoffset = next_good_eraseblock(fd, &meminfo, blockstart);
 			if (IS_NANDWRITE)
 				printf("Writing at 0x%08x\n", mtdoffset);
-			else if (mtdoffset > blockstart && !(opts & OPT_b)) {
-				int bad_len = MIN(mtdoffset, limit) - blockstart;
-				dump_bad(&meminfo, bad_len, opts & OPT_o);
+			else if (mtdoffset > blockstart) {
+				if (bb_method == BB_PADBAD) {
+					/* dump FF padded bad block */
+					int bad_len = MIN(mtdoffset, limit) - blockstart;
+					dump_bad(&meminfo, bad_len, opts & OPT_o);
+				} else if (bb_method == BB_SKIPBAD) {
+					/* for skipbad, increase the length */
+					if ((end_addr + mtdoffset - blockstart) > end_addr)
+						end_addr += (mtdoffset - blockstart);
+					else
+						end_addr = ~0;
+					limit = MIN(meminfo.size, end_addr);
+				}
+				/* omitbad: do nothing */
 			}
 			if (mtdoffset >= limit)
 				break;
-- 
2.0.0