PPC64 & DMA zone

[Aaro Koskinen]

Hi,

On Sat, Aug 18, 2012 at 06:40:56AM +1000, Benjamin Herrenschmidt wrote:
> > The problem I have is that b43 driver (wireless chip) insists a 30-bit
> > DMA mask, but I have 1.5 GB physical memory. So the only way I can get
> > the wireless connection to work is to boot with "mem=1024MB". And as a
> > result my bloaty applications will loose much needed memory...
> 
> Or force the iommu to be enabled, it should be able to service
> constrained DMA (iommu=force on the command line).

I still get the same failure:

DART IOMMU initialized for U3 type chipset
[...]
Kernel command line: ramdisk_size=8192 iommu=force
[...]
Top of RAM: 0x60000000, Total RAM: 0x60000000
Memory hole size: 0MB
Zone ranges:
  DMA      [mem 0x00000000-0x5fffffff]
  Normal   empty
[...]
b43-pci-bridge 0001:01:01.0: Warning: IOMMU window too big for device mask
b43-pci-bridge 0001:01:01.0: mask: 0x3fffffff, table end: 0x80000000
b43-phy0 ERROR: The machine/kernel does not support the required 30-bit DMA mask

A.