ramips: add support for Fon FON2601

FON2601 is a wireless router.

Specification:
- SoC: Mediatek MT7620A (580MHz)
- RAM: 128 MiB
- ROM: 16 MiB SPI Flash
- Wireless:
   for 11b/g/n (upto 300 Mbps):  MT7620A built-in WMAC
   for 11a/n/ac (upto 867 Mbps): MT7662E
- Ethernet LAN: 1 port, upto 100 Mbps
- Ethernet WAN: 1 port, upto 1000 Mbps
- USB: 1 port (USB 2.0 host)
- LEDs: 4 (all can be controlled by SoC's GPIO)
- buttons: 1 (Displayed as "WPS" on enclosure)
- serial port: 57600n8
 pins: Vcc(3.3V), Rx, Tx, GND
(left to right, viewed from outside of board)

Installation (only available via UART):
  1. download sysupgrade binary image by wget command
  2. write sysupgrade binary image to Flash
     command is:
       mtd write sysupgrade.bin firmware
  3. reboot

Important Notice:
  Only one button is displayed as "WPS" on enclosure.
  However, it is configured as "reset" (factory resetting feature).

Signed-off-by: NOGUCHI Hiroshi <drvlabo@gmail.com>
[removed unrelated openwrt-keyring revert, missing -Wall for uimage_padhdr]
Signed-off-by: Petr Štetiar <ynezz@true.cz>

target/linux/generic/files/drivers/mtd/mtdsplit/mtdsplit_uimage.c

@@ -24,9 +24,9 @@
 
 /*
  * uimage_header itself is only 64B, but it may be prepended with another data.
- * Currently the biggest size is for Edimax devices: 20B + 64B
+ * Currently the biggest size is for Fon(Foxconn) devices: 64B + 32B
  */
-#define MAX_HEADER_LEN		84
+#define MAX_HEADER_LEN		96
 
 #define IH_MAGIC	0x27051956	/* Image Magic Number		*/
 #define IH_NMLEN		32	/* Image Name Length		*/
@@ -80,12 +80,12 @@ read_uimage_header(struct mtd_info *mtd, size_t offset, u_char *buf,
  * __mtdsplit_parse_uimage - scan partition and create kernel + rootfs parts
  *
  * @find_header: function to call for a block of data that will return offset
- *      of a valid uImage header if found
+ *      and tail padding length of a valid uImage header if found
  */
 static int __mtdsplit_parse_uimage(struct mtd_info *master,
-				   const struct mtd_partition **pparts,
-				   struct mtd_part_parser_data *data,
-				   ssize_t (*find_header)(u_char *buf, size_t len))
+		   const struct mtd_partition **pparts,
+		   struct mtd_part_parser_data *data,
+		   ssize_t (*find_header)(u_char *buf, size_t len, int *extralen))
 {
 	struct mtd_partition *parts;
 	u_char *buf;
@@ -97,6 +97,7 @@ static int __mtdsplit_parse_uimage(struct mtd_info *master,
 	size_t rootfs_size = 0;
 	int uimage_part, rf_part;
 	int ret;
+	int extralen;
 	enum mtdsplit_part_type type;
 
 	nr_parts = 2;
@@ -120,7 +121,8 @@ static int __mtdsplit_parse_uimage(struct mtd_info *master,
 		if (ret)
 			continue;
 
-		ret = find_header(buf, MAX_HEADER_LEN);
+		extralen = 0;
+		ret = find_header(buf, MAX_HEADER_LEN, &extralen);
 		if (ret < 0) {
 			pr_debug("no valid uImage found in \"%s\" at offset %llx\n",
 				 master->name, (unsigned long long) offset);
@@ -128,7 +130,9 @@ static int __mtdsplit_parse_uimage(struct mtd_info *master,
 		}
 		header = (struct uimage_header *)(buf + ret);
 
-		uimage_size = sizeof(*header) + be32_to_cpu(header->ih_size) + ret;
+		uimage_size = sizeof(*header) +
+				be32_to_cpu(header->ih_size) + ret + extralen;
+
 		if ((offset + uimage_size) > master->size) {
 			pr_debug("uImage exceeds MTD device \"%s\"\n",
 				 master->name);
@@ -206,7 +210,7 @@ err_free_parts:
 	return ret;
 }
 
-static ssize_t uimage_verify_default(u_char *buf, size_t len)
+static ssize_t uimage_verify_default(u_char *buf, size_t len, int *extralen)
 {
 	struct uimage_header *header = (struct uimage_header *)buf;
 
@@ -269,7 +273,7 @@ static struct mtd_part_parser uimage_generic_parser = {
 #define FW_MAGIC_WNDR3700V2	0x33373031
 #define FW_MAGIC_WPN824N	0x31313030
 
-static ssize_t uimage_verify_wndr3700(u_char *buf, size_t len)
+static ssize_t uimage_verify_wndr3700(u_char *buf, size_t len, int *extralen)
 {
 	struct uimage_header *header = (struct uimage_header *)buf;
 	uint8_t expected_type = IH_TYPE_FILESYSTEM;
@@ -332,7 +336,7 @@ static struct mtd_part_parser uimage_netgear_parser = {
 #define FW_EDIMAX_OFFSET	20
 #define FW_MAGIC_EDIMAX		0x43535953
 
-static ssize_t uimage_find_edimax(u_char *buf, size_t len)
+static ssize_t uimage_find_edimax(u_char *buf, size_t len, int *extralen)
 {
 	u32 *magic;
 
@@ -345,7 +349,7 @@ static ssize_t uimage_find_edimax(u_char *buf, size_t len)
 	if (be32_to_cpu(*magic) != FW_MAGIC_EDIMAX)
 		return -EINVAL;
 
-	if (!uimage_verify_default(buf + FW_EDIMAX_OFFSET, len))
+	if (!uimage_verify_default(buf + FW_EDIMAX_OFFSET, len, extralen))
 		return FW_EDIMAX_OFFSET;
 
 	return -EINVAL;
@@ -377,6 +381,49 @@ static struct mtd_part_parser uimage_edimax_parser = {
 	.type = MTD_PARSER_TYPE_FIRMWARE,
 };
 
+
+/**************************************************
+ * Fon(Foxconn)
+ **************************************************/
+
+#define FONFXC_PAD_LEN		32
+
+static ssize_t uimage_find_fonfxc(u_char *buf, size_t len, int *extralen)
+{
+	if (uimage_verify_default(buf, len, extralen) < 0)
+		return -EINVAL;
+
+	*extralen = FONFXC_PAD_LEN;
+
+	return 0;
+}
+
+static int
+mtdsplit_uimage_parse_fonfxc(struct mtd_info *master,
+			      const struct mtd_partition **pparts,
+			      struct mtd_part_parser_data *data)
+{
+	return __mtdsplit_parse_uimage(master, pparts, data,
+				       uimage_find_fonfxc);
+}
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 9, 0)
+static const struct of_device_id mtdsplit_uimage_fonfxc_of_match_table[] = {
+	{ .compatible = "fonfxc,uimage" },
+	{},
+};
+#endif
+
+static struct mtd_part_parser uimage_fonfxc_parser = {
+	.owner = THIS_MODULE,
+	.name = "fonfxc-fw",
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 9, 0)
+	.of_match_table = mtdsplit_uimage_fonfxc_of_match_table,
+#endif
+	.parse_fn = mtdsplit_uimage_parse_fonfxc,
+	.type = MTD_PARSER_TYPE_FIRMWARE,
+};
+
 /**************************************************
  * Init
  **************************************************/
@@ -386,6 +433,7 @@ static int __init mtdsplit_uimage_init(void)
 	register_mtd_parser(&uimage_generic_parser);
 	register_mtd_parser(&uimage_netgear_parser);
 	register_mtd_parser(&uimage_edimax_parser);
+	register_mtd_parser(&uimage_fonfxc_parser);
 
 	return 0;
 }