ath79: add support for KuWFi N650 CPE

ath79: add support for KuWFi N650 CPE

The KuWFi N650 is a 5GHz outdoor wireless bridge based on QCA9563.

Specs
=====

CPU: QCA9563, 775MHz
RAM: 128MiB
Flash: 16MiB
Wireless: QCA9888 (5GHz only)
Ethernet: 2x GBit (via QCA8337), 48V passive PoE

Installation
============

From OEM firmware
-----------------

The OEM firmware has telnet enabled by default. If not, it can be enabled
from the firmware web interface. You need a TFTP server on your computer
and the OpenWrt factory image should be available as "n650factory.bin".
It is assumed that your computer has the IP 192.168.1.1 and the N650
192.168.1.20 (default IP address).

1. Connect via Telnet to the device and log in with the default credentials
   "admin:admin"
2. Exploit the limited interface by typing "ps & /bin/sh"
3. Press <ENTER> to start the shell
4. Enter the following commands:

$ cd /tmp
$ tftp -r n650factory.bin -g 192.168.1.1
$ cat << EOF > /tmp/openwrt.sh
#!/bin/sh

IMAGE_NAME="\$1"

if [ ! -e \${IMAGE_NAME} ]; then
  echo "Image file not found: \${IMAGE_NAME}"
  exit 1
fi

. /usr/sbin/common.sh

kill_remaining TERM
sleep 3
kill_remaining KILL

run_ramfs mtd write \${IMAGE_NAME} firmware
sleep 2
reboot -f
EOF

$ chmod +x /tmp/openwrt.sh
$ /tmp/openwrt.sh n650factory.bin

Once the device reboots, it should load OpenWrt.

From UART
---------

UART installation is possible since the serial header is already soldered
on. The pinout is GND - Tx - Rx - VCC from top to bottom (RJ45 ports are
at the bottom). Connect with 115200 8N1.

First, boot OpenWrt from TFTP. Enter the following commands in the U-Boot
shell, assuming your computer has the IP address 192.168.1.1 and a TFTP
server running where the initramfs image is provided as n650.bin:

  setenv ipaddr 192.168.1.20
  setenv serverip 192.168.1.1
  tftpboot 0x84000000 n650.bin
  bootm

Once booted, transfer -loader.bin and -sysupgrade.bin images to the device
at /tmp. Enter the following commands, replacing the filenames:

  mtd write /tmp/loader.bin loader
  sysupgrade /tmp/sysupgrade.bin

Reboot and OpenWrt should load from flash.

Back to Stock
-------------

Back to stock is only possible if you saved a partition backup before
installing OpenWrt. Assuming you have fullbackup.bin covering the whole
flash, you need to prepare the image as follows:

$ dd if=fullbackup.bin of=fwconcat0.bin bs=65536 skip=4 count=212
$ dd if=fullbackup.bin of=loader.bin bs=65536 skip=216 count=1
$ dd if=fullbackup.bin of=fwconcat1.bin bs=65536 skip=217 count=22
$ cat fwconcat0.bin fwconcat1.bin > firmware.bin

Transfer firmware.bin and loader.bin to the OpenWrt device. First, flash
loader.bin to mtd device loader, then force sysupgrade:

$ mtd write loader.bin loader
$ sysupgrade -F firmware.bin

The reason for the two-step process is the way the flash layout is designed
for OpenWrt in contrast to the OEM firmware partition.

Signed-off-by: Andreas Böhler <dev@aboehler.at>
Link: https://github.com/openwrt/openwrt/pull/17089
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>