Adding OpenWrt support for CAN Star Treasure Box router

Hi, I would like to add a new brand and a new device. CAN Star Treasure Box comes with OpenWrt installed. Here's info from the datasheet:
Wireless B/G/N/AC speed up to 1200Mbps Support AP,WISP wireless mode WAN port support PoE Out, PoE voltage 12v=2.0a Support PoE Pass-through 2x2 MIMO Technology Passive PoE supports up to 100 meter 512MB SDRAM 128MB Flash,770Mhz CPU IPQ 4109 OPENWRT and DDWRT Firmware

Looks like it's IPQ4019. So you can probably use an existing IPQ4019 device as a start. At least it isn't Broadcom-based...

Since it appears to be only marketed in mainland China, there is unfortunately a high chance that the OEM is violating the GPL and not providing kernel source. Otherwise, you'd probably be able to find a lot of the "important" parameters such as flash memory layout in the kernel sources...

They claim OpenWRT - so ideally if they're marketing it, they've already provided their changes somewhere that could potentially be integrated into master.

(Sometimes this is easier said than done - see GL.iNet NAND support as an example, as many of GL.iNet's modifications were considered not acceptable upstream as-is.)