Re: use generic DMA mapping code in powerpc V4

[Christian Zigotzky]

On 28 November 2018 at 12:05PM, Michael Ellerman wrote:
> Christoph Hellwig <hch@xxxxxx> writes:
>
> > Any comments?  I'd like to at least get the ball moving on the easy
> > bits.
> Nothing specific yet.
>
> I'm a bit worried it might break one of the many old obscure platforms
> we have that aren't well tested.
>
> There's not much we can do about that, but I'll just try and test it on
> everything I can find.
>
> Is the plan that you take these via the dma-mapping tree or that they go
> via powerpc?
>
> cheers
Hi All,

I compiled a test kernel from the following Git today.

http://git.infradead.org/users/hch/misc.git/shortlog/refs/heads/powerpc-dma.4

Command: git clone git://git.infradead.org/users/hch/misc.git -b 
powerpc-dma.4 a

Unfortunately I get some DMA error messages and the PASEMI ethernet 
doesn't work anymore.

[Â 367.627623] pci 0000:00:1a.0: dma_direct_map_page: overflow 
0x000000026bcb5002+110 of device mask ffffffff bus mask 0
[Â 367.627631] pci 0000:00:1a.0: dma_direct_map_page: overflow 
0x000000026bcb5002+110 of device mask ffffffff bus mask 0
[Â 367.627639] pci 0000:00:1a.0: dma_direct_map_page: overflow 
0x000000026bcb5002+110 of device mask ffffffff bus mask 0
[Â 367.627647] pci 0000:00:1a.0: dma_direct_map_page: overflow 
0x000000026bcb5002+110 of device mask ffffffff bus mask 0
[Â 367.627655] pci 0000:00:1a.0: dma_direct_map_page: overflow 
0x000000026bcb5002+110 of device mask ffffffff bus mask 0
[Â 367.627686] pci 0000:00:1a.0: dma_direct_map_page: overflow 
0x000000026bcb5002+110 of device mask ffffffff bus mask 0
[Â 367.628418] pci 0000:00:1a.0: dma_direct_map_page: overflow 
0x000000026bcb5002+110 of device mask ffffffff bus mask 0
[Â 367.628505] pci 0000:00:1a.0: dma_direct_map_page: overflow 
0x000000026bcb5002+110 of device mask ffffffff bus mask 0
[Â 367.628592] pci 0000:00:1a.0: dma_direct_map_page: overflow 
0x000000026bcb5002+110 of device mask ffffffff bus mask 0
[Â 367.629324] pci 0000:00:1a.0: dma_direct_map_page: overflow 
0x000000026bcb5002+110 of device mask ffffffff bus mask 0
[Â 367.629417] pci 0000:00:1a.0: dma_direct_map_page: overflow 
0x000000026bcb5002+110 of device mask ffffffff bus mask 0
[Â 367.629495] pci 0000:00:1a.0: dma_direct_map_page: overflow 
0x000000026bcb5002+110 of device mask ffffffff bus mask 0
[Â 367.629589] pci 0000:00:1a.0: dma_direct_map_page: overflow 
0x000000026bcb5002+110 of device mask ffffffff bus mask 0

[Â 430.424732]pasemi_mac: rcmdsta error: 0x04ef3001

I tested this kernel with the Nemo board (CPU: PWRficient PA6T-1682M). 
The PASEMI ethernet works with the RC4 of kernel 4.20.

Cheers,
Christian