RPi-3 brcmfmac errors on boot

[Gerd Hoffmann]

  Hi,

> > When trying again on 4.9 I get the same firmware load error as Don.
> > Kernel with the downstream brcm patch cherry-picked still building atm.
> 
> Hi Gerd,
> 
> I was trying your latest wifi-testing (recently rebased) branch.  I wanted
> to play with the DMA stuff.  For some reason that isn't working for me.
> Both the mmc0 and mmc1 are in PIO mode.
> 
> Looking at your code, I was curious why you are enabling DMA for the sdhost
> controller (mmc card) instead of the SDHCI controller (wifi/bt)?

I'm trying to cleanup/fix the sdhost driver for upstream merge (I
suspect I will not find time to seriously work on in before january,
pre-xmas time is pretty packed), so I tried to enable dma (wifi-testing
branch) for that one, so make sure I don't break dma, only to find that
dma doesn't work even without my cleanup patches.  So, debugging why dma
doesn't work is #1 on my sdhost todo list ...

Didn't try yet to enable dma for sdhci.  Feel free to go ahead ;)
It's dma channel 11 according to the docs (p62):

https://github.com/raspberrypi/documentation/blob/master/hardware/raspberrypi/bcm2835/BCM2835-ARM-Peripherals.pdf

cheers,
  Gerd