mvebu: add support for Fortinet FortiGate 50E

mvebu: add support for Fortinet FortiGate 50E

Fortinet FortiGate 50E (FG-50E) is a UTM, based on Armada 385 (88F6820).

Specification:

- SoC          : Marvell Armada 385 88F6820
- RAM          : DDR3 2 GiB (4x Micron MT41K512M8DA-107, "D9SGQ")
- Flash        : SPI-NOR 128 MiB (Macronix MX66L1G45GMI-10G)
- Ethernet     : 7x 10/100/1000 Mbps
  - LAN 1-5    : Marvell 88E6176
  - WAN 1, 2   : Marvell 88E1512 (2x)
- LEDs/Keys    : 18x/1x
- UART         : "CONSOLE" port (RJ-45, RS-232C level)
  - port       : ttyS0
  - settings   : 9600bps 8n1
  - assignment : 1:NC , 2:NC , 3:TXD, 4:GND,
                 5:GND, 6:RXD, 7:NC , 8:NC
  - note       : compatible with Cisco console cable
- HW Monitoring: nuvoTon NCT7802Y
- Power        : 12 VDC, 2 A
  - plug       : Molex 5557-02R

Flash instruction using initramfs image:

1. Power on FG-50E and interrupt to show bootmenu
2. Call "[R]: Review TFTP parameters.", check TFTP parameters and
   connect computer to "Image download port" in the parameters
3. Prepare TFTP server with the parameters obtained above
4. Rename OpenWrt initramfs image to "image.out" and put to TFTP
   directory
5. Call "[T]: Initiate TFTP firmware transfer." to download initramfs
   image from TFTP server
6. Type "r" key when the following message is showed, to boot initramfs
   image without flashing to spi-nor flash

   "Save as Default firmware/Backup firmware/Run image without saving:[D/B/R]?"

7. On initramfs image, backup mtd if needed

   minimum:

   - "firmware-info"
   - "kernel"
   - "rootfs"

7. On initramfs image, upload sysupgrade image to the device and perform
   sysupgrade
8. Wait ~200 seconds to complete flashing and rebooting.
   If the device is booted with stock firmware, login to bootmenu and
   call "[B]: Boot with backup firmware and set as default." to set the
   first OS image as default and boot it.

Notes:

- All "SPEED" LEDs(Green/Amber) of LAN and 1000M "SPEED" LEDs(Green) of
  WAN1/2 are connected to GPIO expander. There is no way to indicate
  link speed of networking device on Linux Kernel/OpenWrt, so those LEDs
  cannot be handled like stock firmware.
  On OpenWrt, use netdev(link) trigger instead.

- Both colors of Bi-color LEDs on the front panel cannot be turned on at
  the same time.

- "PWR" and "Logo" LEDs are connected to power source directly.

- The following partitions are added for OpenWrt.
  These partitions are contained in "uboot" partition (0x0-0x1fffff) on
  stock firmware.

  - "firmware-info"
  - "dtb"
  - "u-boot-env"
  - "board-info"

Image header for bootmenu tftp:

  0x0 - 0xf  : ?
 0x10 - 0x2f : Image Name
 0x30 - 0x17f: ?
0x180 - 0x183: Kernel Offset*
0x184 - 0x187: Kernel Length*
0x188 - 0x18b: RootFS Offset (ext2)*
0x18c - 0x18f: RootFS Length (ext2)*
0x190 - 0x193: DTB Offset
0x194 - 0x197: DTB Length
0x198 - 0x19b: Data Offset (jffs2)
0x19c - 0x19f: Data Length (jffs2)
0x1a0 - 0x1ff: ?

*: required for initramfs image

MAC addresses:

(eth0): 70:4C:A5:xx:xx:7C (board-info, 0xd880 (hex))
WAN 1 : 70:4C:A5:xx:xx:7D
WAN 2 : 70:4C:A5:xx:xx:7E
LAN 1 : 70:4C:A5:xx:xx:7F
LAN 2 : 70:4C:A5:xx:xx:80
LAN 3 : 70:4C:A5:xx:xx:81
LAN 4 : 70:4C:A5:xx:xx:82
LAN 5 : 70:4C:A5:xx:xx:83

Signed-off-by: INAGAKI Hiroshi <musashino.open@gmail.com>