ath79: add support for NEC Aterm WG1800HP

ath79: add support for NEC Aterm WG1800HP

NEC Aterm WG1800HP is a 2.4/5 GHz band 11ac (Wi-Fi 5) router, based on
QCA9558.

Specification:

- SoC              : Qualcomm Atheros QCA9558
- RAM              : DDR2 128 MiB (2x Nanya NT5TU32M16DG-AC)
- Flash            : SPI-NOR 16 MiB (Macronix MX25L12845EMI-10G)
- WLAN             : 2.4/5 GHz
  - 2.4 GHz        : 3T3R (Qualcomm Atheros QCA9558 (SoC))
  - 5 GHz          : 3T3R (Qualcomm Atheros QCA9880)
- Ethernet         : 5x 10/100/1000 Mbps
  - switch         : Atheros AR8327
- LEDs/Keys (GPIO) : 12x/5x
- UART             : through-hole on PCB
  - assignment     : 3.3V, GND, NC, TX, RX from tri-angle marking
  - settings       : 9600n8
- USB              : 1x USB 2.0 Type-A
  - hub (internal) : NEC uPD720114
- Power            : 12 VDC, 1.5 A (Max. 17 W)
- Stock OS         : NetBSD based

Flash instruction using initramfs-factory.bin image (StockFW WebUI):

1. Boot WG1800HP with router mode normally
2. Access to the WebUI ("http://aterm.me/" or "http://192.168.0.1/") on
   the device and open firmware update page ("ファームウェア更新")
3. Downgrade the stock firmware to v1.0.2
4. After downgrading, select the OpenWrt initramfs-factory.bin image and
   click update ("更新") button
5. After updating, the device will be rebooted and booted with OpenWrt
   initramfs image
6. On the initramfs image, upload (or download) uboot.bin and
   sysupgrade.bin image to the device
7. Replace the bootloader with a uboot.bin image

   mtd write <uboot.bin image> bootloader

8. Perform sysupgrade with a sysupgrade.bin image

   sysupgrade <sysupgrade image>

9. Wait ~120 seconds to complete flashing

Flash instruction using initramfs-factory.bin image (bootloader CLI):

 1. Connect and open serial console
 2. Power on WG1800HP and interrupt bootloader by ESC key
 3. Login to the bootloader CLI with a password "chiron"
 4. Start TFTP server by "tftpd" command
 5. Upload initramfs-factory.bin via tftp from your computer

   example (Windows): tftp -i 192.168.0.1 PUT initramfs-factory.bin

 6. Boot initramfs image by "boot" command
 7. On the initramfs image, back up the stock bootloader and firmware if
   needed
 8. Upload (or download) uboot.bin and sysupgrade.bin image to the device
 9. Replace the bootloader with a uboot.bin image
10. Perform sysupgrade with a sysupgrade.bin image
11. Wait ~120 seconds to complete flashing

Notes:

- All LEDs are connected to the TI TCA6416A (marking: PH416A) I2C
  Expander chip.

- The stock bootloader requires an unknown filesystem on firmware area
  in the flash. Booting of OpenWrt from that filesystem cannot be
  handled, so the bootloader needs to be replaced to mainline U-Boot
  before OpenWrt installation.

- The data length of blocks in firmware image will be checked
  (4M < threshold < 6M) on the stock WebUI on some versions (v1.0.28,
  v1.0.30(latest), ...), so needs to be downgraded before OpenWrt
  installation with initramfs-factory image.

MAC addresses:

LAN    : 10:66:82:xx:xx:04 (config, 0x6 (hex))
WAN    : 10:66:82:xx:xx:05 (config, 0xc (hex))
2.4 GHz: 10:66:82:xx:xx:06 (config, 0x0 (hex))
5 G    : 10:66:82:xx:xx:07 (config, 0x12 (hex))

Signed-off-by: INAGAKI Hiroshi <musashino.open@gmail.com>
Link: https://github.com/openwrt/openwrt/pull/16297
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>