awg: Move MAC soft reset around to avoid soft reset timeout

[kevans]

Summary

From NetBSD: Since the MAC can get stuck in reset state with no link, ignore reset timeouts and continue with
initializing the device.

Fixes "soft reset timeout" issue at boot with no network cable plugged in.

awg_init may be called multiple times throughout normal interface usage, so the tx/rx descriptor base address registers must be written after each MAC reset and are moved as such.

This problem has been observed on FreeBSD, H3/H2+ devices with an internal phy (includes OrangePi R1, OrangePi One at least).

Obtained from: NetBSD

Test Plan

Test w/ OrangePi R1 as well as other boards not previously experiencing any issues.

[manu]

sys/arm/allwinner/if_awg.c

798

Is this really needed ?
I don't really see how moving dma setup here change things.

[kevans]

sys/arm/allwinner/if_awg.c

798

Right, I kind of suspect it's not critical, but I didn't put much time into thinking about it since it was in jmcneill's commit and I think there's good value in staying relatively in-sync

[kevans]

Remove unrelated DMA change

[kevans]

Further testing reveals that awg doesn't consistently work without the removed DMA change. I don't know much about network drivers, but I suspect awg_init is being called multiple times and the soft reset wipes out EMAC_{TX,RX}_DMA_LIST. They aren't being reset in this path, only on attach.

[kevans]

Restore the original version; awg_init will be called as an interface is down'd and up'd throughout the course of normal usage that the MAC reset will wipe out these registers. Otherwise, you end up with a not-actually-stable awg interface.

[manu]

In D18844#402482, @kevans wrote:

Restore the original version; awg_init will be called as an interface is down'd and up'd throughout the course of normal usage that the MAC reset will wipe out these registers. Otherwise, you end up with a not-actually-stable awg interface.

Ah ok, make sense now.
Thanks.