qualcommax: ipq50xx: add support for Linksys SPNMX56

qualcommax: ipq50xx: add support for Linksys SPNMX56

The SPNMX56 is an ISP-branded and distributed device similar to the MX5500
with the same Wifi chips (IPQ5018 for 2.4G and QCN9074 for 5G) but has an
additional QCA8081 PHY providing a 2.5gbps ethernet WAN port.

Speficiations:
* SoC: Qualcomm IPQ5018 (64-bit dual-core ARM Cortex-A53 @ 1.0Ghz)
* Memory: Winbond W634GU6NB-11 (512 MiB DDR3-933)
* Serial Port: 3v3 TTL 115200n8
* Wi-Fi: IPQ5018 (2x2 2.4 Ghz 802.11b/g/n/ax)
         QCN9024 (4x4:4 5 Ghz 802.11an/ac/ax)
* Ethernet: IPQ5018 integrated virtual switch connected to an external
            QCA8337 switch (3 Ports 10/100/1000 GBASE-T) and a
            QCA8081 phy (up to 2.5 Gbps)
* Flash: Gigadevice GD5F2GM7RExxG (256 MiB)
* LEDs: 1x multi-color PWM LED
* Buttons: 1x WPS (GPIO 27 Active Low)
           1x Reset (GPIO 28 Acive Low)

Flash instructions:
1. On OEM firmware, login to the device (typically at http://192.168.1.1)
and click 'CA' in the bottom right corner -> Connectivity ->
Manual Upgrade. Alternatively, browse to http://<router IP>/fwupdate.html
Upload openwrt-qualcommax-ipq50xx-linksys_spnmx56-squashfs-factory.bin
Optionally flash 2nd partition, after first boot check actual partition:
fw_printenv -n boot_part
and install firmware on second partition using command in case of 2:
mtd -r -e kernel -n write openwrt-qualcommax-ipq50xx-linksys_spnmx56-squashfs-factory.bin kernel
and in case of 1:
mtd -r -e alt_kernel -n write openwrt-qualcommax-ipq50xx-linksys_spnmx56-squashfs-factory.bin alt_kernel
2. Installation using serial connection from OEM firmware
hit Enter once booted and enter credentials (login: root, password: admin)
fw_printenv -n boot_part
In case of 2:
flash_erase /dev/mtd12 0 0
nandwrite -p /dev/mtd12 openwrt-qualcommax-ipq50xx-linksys_spnmx56-squashfs-factory.bin
or in case of 1:
flash_erase /dev/mtd14 0 0
nandwrite -p /dev/mtd14 openwrt-qualcommax-ipq50xx-linksys_spnmx56-squashfs-factory.bin
After first boot install firmware on second partition:
mtd -r -e kernel -n write openwrt-qualcommax-ipq50xx-linksys_spnmx56-squashfs-factory.bin kernel
or:
mtd -r -e alt_kernel -n write openwrt-qualcommax-ipq50xx-linksys_spnmx56-squashfs-factory.bin alt_kernel
3. Back to the OEM firmware.
Download firmware from OEM website:
Firmware for this device cannot be searched for on the Linksys website.
Instead, we'd have to use serial to intercept the URL of the firmware
while it's trying to update. Firmware is ISP specific:
Toob (UK): http://download.linksys.com/updates/20241125t080737/FW_MX56TB_1.0.1.216218_prod.img

The intention is to collect URLs for different ISPs on a wiki page.

From serial or SSH:
fw_printenv boot_part
in case of 1:
mtd -r -e alt_kernel -n write FW_MX56TB_1.0.1.216218_prod.img alt_kernel
else in case of 2:
mtd -r -e kernel -n write FW_MX56TB_1.0.1.216218_prod.img kernel

Signed-off-by: George Moussalem <george.moussalem@outlook.com>
Link: https://github.com/openwrt/openwrt/pull/17968
Signed-off-by: Robert Marko <robimarko@gmail.com>