Re: Alpha: virt_to_bus/GFP_DMA problem
Richard Henderson (rth@cygnus.com)
Fri, 10 Dec 1999 08:22:14 -0800
On Fri, Dec 10, 1999 at 04:13:32PM +0100, Thomas Sailer wrote:
> > handle = pci_map_single(pci_dev *dev, void *addr, long len, int flags)
> > or
> > handle = pci_map_sg(pci_dev *dev, struct scatterlist *sg, int flags)
>
> Hm? How is that supposed to work? In our case, the DMA controller
> sits in the PCI device, and the problem is the inadequacy of this
> controller.
No, Jakub does in fact have the correct answer. On both Alpha
and Sparc we have fairly sophisticated control over how bus
addresses map back to memory addresses. Efficient use of that
control, however, requires driver assistance.
r~
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