1 files changed, 90 insertions, 18 deletions

diff --git a/package/system/mtd/src/linksys_bootcount.c b/package/system/mtd/src/linksys_bootcount.c
index 500ede4972..bd06728696 100644
--- a/package/system/mtd/src/linksys_bootcount.c
+++ b/package/system/mtd/src/linksys_bootcount.c
@@ -2,6 +2,7 @@
  * Linksys boot counter reset code for mtd
  *
  * Copyright (C) 2013 Jonas Gorski <jogo@openwrt.org>
+ * Portions Copyright (c) 2019, Jeff Kletsky
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License v2
@@ -29,6 +30,7 @@
 #include <string.h>
 #include <errno.h>
 #include <stdint.h>
+#include <syslog.h>
 
 #include <sys/ioctl.h>
 #include <mtd/mtd-user.h>
@@ -37,6 +39,30 @@
 
 #define BOOTCOUNT_MAGIC	0x20110811
 
+/*
+ * EA6350v3, and potentially other NOR-boot devices,
+ * use an offset increment of 16 between records,
+ * not mtd_info_user.writesize (often 1 on NOR devices).
+ */
+
+#define BC_OFFSET_INCREMENT_MIN 16
+
+
+
+#define DLOG_OPEN()
+
+#define DLOG_ERR(...) do {						       \
+		fprintf(stderr, "ERROR: " __VA_ARGS__); fprintf(stderr, "\n"); \
+	} while (0)
+
+#define DLOG_NOTICE(...) do {						\
+		fprintf(stderr, __VA_ARGS__); fprintf(stderr, "\n");	\
+	} while (0)
+
+#define DLOG_DEBUG(...)
+
+
+
 struct bootcounter {
 	uint32_t magic;
 	uint32_t count;
@@ -50,25 +76,50 @@ int mtd_resetbc(const char *mtd)
 	struct mtd_info_user mtd_info;
 	struct bootcounter *curr = (struct bootcounter *)page;
 	unsigned int i;
+	unsigned int bc_offset_increment;
 	int last_count = 0;
 	int num_bc;
 	int fd;
 	int ret;
+	int retval = 0;
+
+	DLOG_OPEN();
 
 	fd = mtd_check_open(mtd);
 
 	if (ioctl(fd, MEMGETINFO, &mtd_info) < 0) {
-		fprintf(stderr, "failed to get mtd info!\n");
-		return -1;
+		DLOG_ERR("Unable to obtain mtd_info for given partition name.");
+
+		retval = -1;
+		goto out;
+	}
+
+
+	/* Detect need to override increment (for EA6350v3) */
+
+	if (mtd_info.writesize < BC_OFFSET_INCREMENT_MIN) {
+
+		bc_offset_increment = BC_OFFSET_INCREMENT_MIN;
+		DLOG_DEBUG("Offset increment set to %i for writesize of %i",
+			   bc_offset_increment, mtd_info.writesize);
+	} else {
+
+		bc_offset_increment = mtd_info.writesize;
 	}
 
-	num_bc = mtd_info.size / mtd_info.writesize;
+	num_bc = mtd_info.size / bc_offset_increment;
 
 	for (i = 0; i < num_bc; i++) {
-		pread(fd, curr, sizeof(*curr), i * mtd_info.writesize);
+		pread(fd, curr, sizeof(*curr), i * bc_offset_increment);
+
+		/* Existing code assumes erase is to 0xff; left as-is (2019) */
 
-		if (curr->magic != BOOTCOUNT_MAGIC && curr->magic != 0xffffffff) {
-			fprintf(stderr, "unexpected magic %08x, bailing out\n", curr->magic);
+		if (curr->magic != BOOTCOUNT_MAGIC &&
+		    curr->magic != 0xffffffff) {
+			DLOG_ERR("Unexpected magic %08x at offset %08x; aborting.",
+				 curr->magic, i * bc_offset_increment);
+
+			retval = -2;
 			goto out;
 		}
 
@@ -78,38 +129,59 @@ int mtd_resetbc(const char *mtd)
 		last_count = curr->count;
 	}
 
-	/* no need to do writes when last boot count is already 0 */
-	if (last_count == 0)
+
+	if (last_count == 0) {	/* bootcount is already 0 */
+
+		retval = 0;
 		goto out;
+	}
 
 
 	if (i == num_bc) {
+		DLOG_NOTICE("Boot-count log full with %i entries; erasing (expected occasionally).",
+			    i);
+
 		struct erase_info_user erase_info;
 		erase_info.start = 0;
 		erase_info.length = mtd_info.size;
 
-		/* erase block */
 		ret = ioctl(fd, MEMERASE, &erase_info);
 		if (ret < 0) {
-			fprintf(stderr, "failed to erase block: %i\n", ret);
-			return -1;
+			DLOG_ERR("Failed to erase boot-count log MTD; ioctl() MEMERASE returned %i",
+				 ret);
+
+			retval = -3;
+			goto out;
 		}
 
 		i = 0;
 	}
 
-	memset(curr, 0xff, mtd_info.writesize);
+	memset(curr, 0xff, bc_offset_increment);
 
 	curr->magic = BOOTCOUNT_MAGIC;
 	curr->count = 0;
 	curr->checksum = BOOTCOUNT_MAGIC;
 
-	ret = pwrite(fd, curr, mtd_info.writesize, i * mtd_info.writesize);
-	if (ret < 0)
-		fprintf(stderr, "failed to write: %i\n", ret);
-	sync();
+	/* Assumes bc_offset_increment is a multiple of mtd_info.writesize */
+
+	ret = pwrite(fd, curr, bc_offset_increment, i * bc_offset_increment);
+	if (ret < 0) {
+		DLOG_ERR("Failed to write boot-count log entry; pwrite() returned %i",
+			 errno);
+		retval = -4;
+		goto out;
+
+	} else {
+		sync();
+
+		DLOG_NOTICE("Boot count sucessfully reset to zero.");
+
+		retval = 0;
+		goto out;
+	}
+
 out:
 	close(fd);
-
-	return 0;
+	return retval;
 }