On 3 June 2015 at 15:07, Hans Verkuil wrote:
> On 06/03/15 10:41, Russell King - ARM Linux wrote:
>> On Wed, Jun 03, 2015 at 08:39:55AM +0200, Hans Verkuil wrote:
>>> Hi Sumit,
>>>
>>> On 05/05/2015 04:41 PM, Sumit Semwal wrote:
Hi Russell, everyone,
First up, sincere apologies for
On 06/03/15 10:41, Russell King - ARM Linux wrote:
> On Wed, Jun 03, 2015 at 08:39:55AM +0200, Hans Verkuil wrote:
>> Hi Sumit,
>>
>> On 05/05/2015 04:41 PM, Sumit Semwal wrote:
>>> Hi Russell, everyone,
>>>
>>> First up, sincere apologies for being awol for sometime; had some
>>> personal / medica
On Wed, Jun 03, 2015 at 08:39:55AM +0200, Hans Verkuil wrote:
> Hi Sumit,
>
> On 05/05/2015 04:41 PM, Sumit Semwal wrote:
> > Hi Russell, everyone,
> >
> > First up, sincere apologies for being awol for sometime; had some
> > personal / medical things to take care of, and then I thought I'd wait
Hi Sumit,
On 05/05/2015 04:41 PM, Sumit Semwal wrote:
> Hi Russell, everyone,
>
> First up, sincere apologies for being awol for sometime; had some
> personal / medical things to take care of, and then I thought I'd wait
> for the merge window to get over before beginning to discuss this
> again.
On Tue, Feb 03, 2015 at 10:42:26PM +0100, Arnd Bergmann wrote:
> Right, if you have a private iommu, there is no problem. The tricky part
> is using a single driver for the system-level translation and the gpu
> private mappings when there is only one type of iommu in the system.
You've got a prob
On Tue, Feb 3, 2015 at 10:42 PM, Arnd Bergmann wrote:
>> Again assuming I'm not confused can't we just solve this by pushing the
>> dma api abstraction down one layer for just the gpu, and let it use its
>> private iommmu directly? Steps for binding a buffer would be:
>> 1. dma_map_sg
>> 2. Noodle
On Tuesday 03 February 2015 12:35:34 Rob Clark wrote:
>
> I can't think of cases outside of GPU's.. if it were more common I'd
> be in favor of teaching dma api about multiple contexts, but right now
> I think that would just amount to forcing a lot of churn on everyone
> else for the benefit of
On Tuesday 03 February 2015 21:04:35 Daniel Vetter wrote:
> - On many soc people love to reuse iommus with the same or similar
> interface all over the place. The solution thus far adopted on arm
> platforms is to write an iommu driver for those and then implement the
> dma-api on top of thi
On Tue, Feb 03, 2015 at 12:35:34PM -0500, Rob Clark wrote:
> On Tue, Feb 3, 2015 at 11:58 AM, Russell King - ARM Linux
> wrote:
> >
> > Okay, but switching contexts is not something which the DMA API has
> > any knowledge of (so it can't know which context to associate with
> > which mapping.) Wh
On Tue, Feb 03, 2015 at 05:36:59PM +0100, Arnd Bergmann wrote:
> On Tuesday 03 February 2015 11:22:01 Rob Clark wrote:
> > On Tue, Feb 3, 2015 at 11:12 AM, Arnd Bergmann wrote:
> > > I agree for the case you are describing here. From what I understood
> > > from Rob was that he is looking at somet
On Tue, Feb 3, 2015 at 11:58 AM, Russell King - ARM Linux
wrote:
>
> Okay, but switching contexts is not something which the DMA API has
> any knowledge of (so it can't know which context to associate with
> which mapping.) While it knows which device, it has no knowledge
> (nor is there any way
On Tue, Feb 03, 2015 at 11:22:01AM -0500, Rob Clark wrote:
> On Tue, Feb 3, 2015 at 11:12 AM, Arnd Bergmann wrote:
> > I agree for the case you are describing here. From what I understood
> > from Rob was that he is looking at something more like:
> >
> > Fig 3
> > CPU--L1cache--L2cache--Memory--I
On Tue, Feb 03, 2015 at 05:12:40PM +0100, Arnd Bergmann wrote:
> On Tuesday 03 February 2015 15:54:04 Russell King - ARM Linux wrote:
> > On Tue, Feb 03, 2015 at 04:31:13PM +0100, Arnd Bergmann wrote:
> > > The dma_map_* interfaces assign the virtual addresses internally,
> > > using typically eith
On Tuesday 03 February 2015 11:22:01 Rob Clark wrote:
> On Tue, Feb 3, 2015 at 11:12 AM, Arnd Bergmann wrote:
> > I agree for the case you are describing here. From what I understood
> > from Rob was that he is looking at something more like:
> >
> > Fig 3
> > CPU--L1cache--L2cache--Memory--IOMMU-
On Tue, Feb 3, 2015 at 11:12 AM, Arnd Bergmann wrote:
> I agree for the case you are describing here. From what I understood
> from Rob was that he is looking at something more like:
>
> Fig 3
> CPU--L1cache--L2cache--Memory--IOMMU-device
>
> where the IOMMU controls one or more contexts per d
On Tuesday 03 February 2015 15:54:04 Russell King - ARM Linux wrote:
> On Tue, Feb 03, 2015 at 04:31:13PM +0100, Arnd Bergmann wrote:
> > The dma_map_* interfaces assign the virtual addresses internally,
> > using typically either a global address space for all devices, or one
> > address space per
On Tue, Feb 03, 2015 at 04:31:13PM +0100, Arnd Bergmann wrote:
> On Tuesday 03 February 2015 15:22:05 Russell King - ARM Linux wrote:
> > Don't we already have those in the DMA API? dma_sync_*() ?
> >
> > dma_map_sg() - sets up the system MMU and deals with initial cache
> > coherency handling. D
On Tuesday 03 February 2015 15:22:05 Russell King - ARM Linux wrote:
> On Tue, Feb 03, 2015 at 03:52:48PM +0100, Arnd Bergmann wrote:
> > On Tuesday 03 February 2015 14:41:09 Russell King - ARM Linux wrote:
> > > I'd go as far as saying that the "DMA API on top of IOMMU" is more
> > > intended to b
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