handle the dual-firmware layout on the WRT1900AC

Signed-off-by: Imre Kaloz <kaloz@openwrt.org>

SVN-Revision: 41384

target/linux/mvebu/patches-3.14/100-find_active_root.patch

@@ -0,0 +1,153 @@
+The WRT1900AC among other Linksys routers uses a dual-firmware layout.
+The bootloader passes the active rootfs in bootargs and also sets the
+rootfstype to jffs2 - which is clearly something we don't want.
+
+Rename both root= and rootfstype= variables to avoid issues and also
+use the former to dynamically rename the active partition to "ubi".
+
+
+Signed-off-by: Imre Kaloz <kaloz@openwrt.org>
+
+--- a/arch/arm/boot/compressed/atags_to_fdt.c
++++ b/arch/arm/boot/compressed/atags_to_fdt.c
+@@ -64,6 +64,18 @@ static uint32_t get_cell_size(const void
+ 	return cell_size;
+ }
+ 
++static void mangle_bootargs(void *fdt, const char *fdt_cmdline)
++{
++	char *rootdev;
++	char *rootfs;
++
++	rootdev = strstr(fdt_cmdline, "root=/dev/mtdblock");
++	strncpy(rootdev, "uboot_active_root=", 18);
++
++	rootfs = strstr(fdt_cmdline, "rootfstype");
++	strncpy(rootfs, "origfstype", 10);
++}
++
+ static void merge_fdt_bootargs(void *fdt, const char *fdt_cmdline)
+ {
+ 	char cmdline[COMMAND_LINE_SIZE];
+@@ -133,6 +145,9 @@ int atags_to_fdt(void *atag_list, void *
+ 
+ 	for_each_tag(atag, atag_list) {
+ 		if (atag->hdr.tag == ATAG_CMDLINE) {
++			/* Rename the original root= and rootfstype= options */
++			mangle_bootargs(fdt,
++					   atag->u.cmdline.cmdline);
+ 			/* Append the ATAGS command line to the device tree
+ 			 * command line.
+ 			 * NB: This means that if the same parameter is set in
+--- a/arch/arm/boot/compressed/string.c
++++ b/arch/arm/boot/compressed/string.c
+@@ -111,6 +111,53 @@ char *strchr(const char *s, int c)
+ 	return (char *)s;
+ }
+ 
++/**
++ * strncpy - Copy a length-limited, %NUL-terminated string
++ * @dest: Where to copy the string to
++ * @src: Where to copy the string from
++ * @count: The maximum number of bytes to copy
++ *
++ * The result is not %NUL-terminated if the source exceeds
++ * @count bytes.
++ *
++ * In the case where the length of @src is less than  that  of
++ * count, the remainder of @dest will be padded with %NUL.
++ *
++ */
++char *strncpy(char *dest, const char *src, size_t count)
++{
++	char *tmp = dest;
++
++	while (count) {
++		if ((*tmp = *src) != 0)
++			src++;
++		tmp++;
++		count--;
++	}
++	return dest;
++}
++
++/**
++ * strstr - Find the first substring in a %NUL terminated string
++ * @s1: The string to be searched
++ * @s2: The string to search for
++ */
++char *strstr(const char *s1, const char *s2)
++{
++	size_t l1, l2;
++
++	l2 = strlen(s2);
++	if (!l2)
++		return (char *)s1;
++	l1 = strlen(s1);
++	while (l1 >= l2) {
++		l1--;
++		if (!memcmp(s1, s2, l2))
++			return (char *)s1;
++		s1++;
++	}
++	return NULL;
++}
+ #undef memset
+ 
+ void *memset(void *s, int c, size_t count)
+--- a/drivers/mtd/ofpart.c
++++ b/drivers/mtd/ofpart.c
+@@ -25,12 +25,15 @@ static bool node_has_compatible(struct d
+ 	return of_get_property(pp, "compatible", NULL);
+ }
+ 
++static int uboot_active_root;
++
+ static int parse_ofpart_partitions(struct mtd_info *master,
+ 				   struct mtd_partition **pparts,
+ 				   struct mtd_part_parser_data *data)
+ {
+ 	struct device_node *node;
+ 	const char *partname;
++	const char *owrtpart = "ubi";
+ 	struct device_node *pp;
+ 	int nr_parts, i;
+ 
+@@ -78,9 +81,15 @@ static int parse_ofpart_partitions(struc
+ 		(*pparts)[i].offset = of_read_number(reg, a_cells);
+ 		(*pparts)[i].size = of_read_number(reg + a_cells, s_cells);
+ 
+-		partname = of_get_property(pp, "label", &len);
+-		if (!partname)
+-			partname = of_get_property(pp, "name", &len);
++		if (uboot_active_root && (i == uboot_active_root)) {
++				partname = owrtpart;
++		} else {
++			partname = of_get_property(pp, "label", &len);
++
++			if (!partname)
++				partname = of_get_property(pp, "name", &len);
++		}
++
+ 		(*pparts)[i].name = partname;
+ 
+ 		if (of_get_property(pp, "read-only", &len))
+@@ -178,6 +187,18 @@ static int __init ofpart_parser_init(voi
+ 	return 0;
+ }
+ 
++static int __init active_root(char *str)
++{
++	get_option(&str, &uboot_active_root);
++
++	if (!uboot_active_root)
++		return 1;
++
++	return 1;
++}
++
++__setup("uboot_active_root=", active_root);
++
+ static void __exit ofpart_parser_exit(void)
+ {
+ 	deregister_mtd_parser(&ofpart_parser);