Messages in this thread | | | Date | Fri, 9 May 2008 09:23:29 +0900 | Subject | Re: [RFC][PATCH] x86 calgary: add fallback dma_ops]] | From | FUJITA Tomonori <> |
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On Thu, 08 May 2008 16:41:51 -0700 Alexis Bruemmer <alexisb@us.ibm.com> wrote:
> On Fri, 2008-05-09 at 08:13 +0900, FUJITA Tomonori wrote: > > On Thu, 08 May 2008 14:40:20 -0700 > > Alexis Bruemmer <alexisb@us.ibm.com> wrote: > > > > > Currently the calgary code can give drivers addresses above 4GB which is > > > very bad for hardware that is only 32bit DMA addressable. This patch > > > "teaches" calgary to fallback to the appropriate dma_ops when it > > > encounters a device/bus which is not behind the Calgary/CalIOC2. I > > > believe there is a better way to do this and am open for ideas, but for > > > now this certainly fixes the badness. > > > > I'm not sure that I correctly understand what you want. You mean that > > the Calgary IOMMU code ignores device's dma_mask and gives addresses > > above 4GB or the Calgary IOMMU code wrongly handles devices that are > > not behind the Calgary? > The real issue is the latter-- the Calgary IOMMU code does not properly > handle devices that are not behind the Calgary/CalIO2.
Thanks, now I see why you use swiotlb for such devices in the case of end_pfn > MAX_DMA32_PFN and no_dma_ops works for them in the case of of end_pfn < MAX_DMA32_PFN.
Can we put a pointer to dma_ops in struct device (archdata) like POWER does? The way to setup and handle x86 IOMMUs seems to become hacky day by day.
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