Realtek 8188eu on kernel 4.4 for A13

[matteosilex]

Hello,

we are running OpenWRT (kernel v4.4.120) on a custom board based on your A13-SOM-256 module.
On it, we use the WM294-V2 by CC&C, a wifi module based on the Realtek 8188eu chip.
At the moment we are using the opensource 8188eu driver by lfinger, but we have really bad bandwidth (40Kbps) and occasional disconnections.
We have tested the official Realtek driver on the official debian image by Olimex (which is based on the sunxi kernel) and the performance is much better, so we would like to use the Realtek driver on our system.

Unfortunately the Realtek driver we have depends on the sunxi kernel, while we need to use mainline kernel 4.4. The official Realtek driver that the module manufacturer gave us, even the latest, supports our SoC (Allwinner A13 sun5i) on sunxi kernels only (so, up to version 3.x, no 4.x support).
It does support kernels up to 4.14, but on Intel, not on on sunxi Arm.

To go into the details, the Realtek driver build for A13 chips depends on kernel functions that have since been deprecated on mainline (even after the sunxi support has been brought in) and removed.
Mostly they are functions to deal with fex files, which have been superseded by Linux's device tree (e.g. script_get_item())
However there are also some calls to USB HCD functions that were also specific to sunxi kernerl 3.x and that are no longer present, (e.g. sw_usb_enable_hcd(), sw_usb_disable_hcd()...)

Is anybody aware of a version of the Realtek 8188eu driver that builds on mainline kernel 4.4 for sunxi architectures?

(Just to clarify, we did try the obvious option of getting in touch with Realtek, but we have had no response...)