mtd: add linksys_bootcount to the ipq40xx target

This commit adds the object 'linksys_bootcount_fix.o' to the ipq40xx
target.

This is needed for the Linksys EA6350v3 device. Without this patch, the
device will switch-back between the current and the last flashed firmware
every 3 (three) reboots. With this patch, the device works as expected.

Signed-off-by: Ryan Pannell <ryan@osukl.com>
Signed-off-by: Oever González <notengobattery@gmail.com>

package/system/mtd/src/Makefile

@@ -15,6 +15,7 @@ obj.ramips = $(obj.seama) $(obj.wrg)
 obj.mvebu = linksys_bootcount.o
 obj.kirkwood = linksys_bootcount.o
 obj.ipq806x = linksys_bootcount.o
+obj.ipq40xx = linksys_bootcount_fix.o
 
 ifdef FIS_SUPPORT
   obj += fis.o

package/system/mtd/src/linksys_bootcount_fix.c

@@ -0,0 +1,115 @@
+/*
+ * Linksys boot counter reset code for mtd
+ *
+ * Copyright (C) 2013 Jonas Gorski <jogo@openwrt.org>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License v2
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stddef.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <endian.h>
+#include <string.h>
+#include <errno.h>
+#include <stdint.h>
+
+#include <sys/ioctl.h>
+#include <mtd/mtd-user.h>
+
+#include "mtd.h"
+
+#define BOOTCOUNT_MAGIC	0x20110811
+
+struct bootcounter {
+	uint32_t magic;
+	uint32_t count;
+	uint32_t checksum;
+};
+
+static char page[2048];
+
+int mtd_resetbc(const char *mtd)
+{
+	struct mtd_info_user mtd_info;
+	struct bootcounter *curr = (struct bootcounter *)page;
+	unsigned int i;
+	int last_count = 0;
+	int num_bc;
+	int fd;
+	int ret;
+
+	fd = mtd_check_open(mtd);
+
+	if (ioctl(fd, MEMGETINFO, &mtd_info) < 0) {
+		fprintf(stderr, "failed to get mtd info!\n");
+		return -1;
+	}
+
+	num_bc = mtd_info.size / 16;
+
+	for (i = 0; i < num_bc; i++) {
+		pread(fd, curr, sizeof(*curr), i * 16);
+
+		if (curr->magic != (BOOTCOUNT_MAGIC) && curr->magic != 0xffffffff) {
+			fprintf(stderr, "unexpected magic %08x, bailing out\n", curr->magic);
+			goto out;
+		}
+
+		if (curr->magic == 0xffffffff)
+			break;
+
+		last_count = curr->count;
+	}
+
+	/* no need to do writes when last boot count is already 0 */
+	if (last_count == 0)
+		goto out;
+
+
+	if (i == num_bc) {
+		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;
+		}
+
+		i = 0;
+	}
+
+	memset(curr, 0xff, 16);
+
+	curr->magic = BOOTCOUNT_MAGIC;
+	curr->count = 0;
+	curr->checksum = BOOTCOUNT_MAGIC;
+
+	ret = pwrite(fd, curr, 16, i * 16);
+	if (ret < 0)
+		fprintf(stderr, "failed to write: %i\n", ret);
+	sync();
+out:
+	close(fd);
+
+	return 0;
+}