On 11/01/17 12:37, Nikita Yushchenko wrote:
>> I actually have a third variation of this problem involving a PCI root
>> complex which *could* drive full-width (40-bit) addresses, but won't,
>> due to the way its PCI<->AXI interface is programmed. That would require
>> even more complicated dma-ran
On Wednesday, January 11, 2017 3:37:22 PM CET Nikita Yushchenko wrote:
> > I actually have a third variation of this problem involving a PCI root
> > complex which *could* drive full-width (40-bit) addresses, but won't,
> > due to the way its PCI<->AXI interface is programmed. That would require
>
> I actually have a third variation of this problem involving a PCI root
> complex which *could* drive full-width (40-bit) addresses, but won't,
> due to the way its PCI<->AXI interface is programmed. That would require
> even more complicated dma-ranges handling to describe the windows of
> valid
On Tuesday, January 10, 2017 2:16:57 PM CET Robin Murphy wrote:
> On 10/01/17 13:42, Arnd Bergmann wrote:
> > On Tuesday, January 10, 2017 1:25:12 PM CET Robin Murphy wrote:
> >> On 10/01/17 12:47, Nikita Yushchenko wrote:
> The point here is that an IOMMU doesn't solve your issue, and the
> >
On Tuesday, January 10, 2017 1:25:12 PM CET Robin Murphy wrote:
> On 10/01/17 12:47, Nikita Yushchenko wrote:
> >> The point here is that an IOMMU doesn't solve your issue, and the
> >> IOMMU-backed DMA ops need the same treatment. In light of that, it really
> >> feels to me like the DMA masks sho
On Tue, Jan 10, 2017 at 02:42:23PM +0100, Arnd Bergmann wrote:
> It's a much rarer problem for the IOMMU case though, because it only
> impacts devices that are restricted to addressing of less than 32-bits.
>
> If you have an IOMMU enabled, the dma-mapping interface does not care
> if the device
On Tue, Jan 10, 2017 at 01:25:12PM +, Robin Murphy wrote:
> We still need a way for drivers to communicate a device's probed
> addressing capability to SWIOTLB, so there's always going to have to be
> *some* sort of public interface. Personally, the change in semantics I'd
> like to see is to m
On Tue, Jan 10, 2017 at 03:47:25PM +0300, Nikita Yushchenko wrote:
> With this direction, semantics of dma mask becomes even more
> questionable. I'd say dma_mask is candidate for removal (or to move to
> swiotlb's or iommu's local area)
We need the dma mask so that the device can advertise what a
On 10/01/17 13:42, Arnd Bergmann wrote:
> On Tuesday, January 10, 2017 1:25:12 PM CET Robin Murphy wrote:
>> On 10/01/17 12:47, Nikita Yushchenko wrote:
The point here is that an IOMMU doesn't solve your issue, and the
IOMMU-backed DMA ops need the same treatment. In light of that, it rea
>> What issue "IOMMU doesn't solve"?
>>
>> Issue I'm trying to address is - inconsistency within swiotlb
>> dma_map_ops, where (1) any wide mask is silently accepted, but (2) then
>> mask is used to decide if bounce buffers are needed or not. This
>> inconsistency causes NVMe+R-Car cobmo not workin
On 10/01/17 12:47, Nikita Yushchenko wrote:
> Hi
>
>> The point here is that an IOMMU doesn't solve your issue, and the
>> IOMMU-backed DMA ops need the same treatment. In light of that, it really
>> feels to me like the DMA masks should be restricted in of_dma_configure
>> so that the parent mask
On Tuesday, January 10, 2017 3:47:25 PM CET Nikita Yushchenko wrote:
>
> > The point here is that an IOMMU doesn't solve your issue, and the
> > IOMMU-backed DMA ops need the same treatment. In light of that, it really
> > feels to me like the DMA masks should be restricted in of_dma_configure
> >
Hi
> The point here is that an IOMMU doesn't solve your issue, and the
> IOMMU-backed DMA ops need the same treatment. In light of that, it really
> feels to me like the DMA masks should be restricted in of_dma_configure
> so that the parent mask is taken into account there, rather than hook
> int
On Mon, Jan 09, 2017 at 10:30:02AM +0300, Nikita Yushchenko wrote:
> It is possible that device is capable of 64-bit DMA addresses, and
> device driver tries to set wide DMA mask, but bridge or bus used to
> connect device to the system can't handle wide addresses.
>
> With swiotlb, memory above 4
It is possible that device is capable of 64-bit DMA addresses, and
device driver tries to set wide DMA mask, but bridge or bus used to
connect device to the system can't handle wide addresses.
With swiotlb, memory above 4G still can be used by drivers for streaming
DMA, but *dev->mask and dev->dma
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