aarch64 -current support for audio on RPI4

[Mayuresh <mayuresh%acm.org@localhost>]

As per the wiki: https://wiki.netbsd.org/ports/evbarm/raspberry_pi/

    RPI3/RPI4 audio with aarch64 kernels
    
        Previously the driver was only included with 32-bit (ARMv7/ARMv6)
        kernels, now works due to dma-ranges[1].

    [1] https://mail-index.netbsd.org/source-changes-d/2021/01/22/msg013133.html

I have installed aarch64 current (22 Jul image) on RPI4 8G and set the
audio output to audio jack by setting hdmi_ignore_edid_audio=1.

audioplay says:

    audioplay: failed to open /dev/sound0: Device not configured

mplayer says:

    [AO SUN] Can't open audio device /dev/audio, Device not configured  -> nosound.

I am not sure from above notes, whether it is possible to get audio
working on RPI4 using aarch64 current.

Please advise.

-- 
Mayuresh