Re: [PATCH 05/13] iommu/io-pgtable-arm: Allow appropriate DMA API use

2015-08-06 Thread Laurent Pinchart
Hi Will, On Wednesday 05 August 2015 17:24:52 Will Deacon wrote: > On Tue, Aug 04, 2015 at 09:54:27PM +0100, Laurent Pinchart wrote: > > On Tuesday 04 August 2015 15:56:42 Russell King - ARM Linux wrote: > > > On Tue, Aug 04, 2015 at 03:47:13PM +0100, Robin Murphy wrote: > > > > On 04/08/15 14:16,

Re: [PATCH 05/13] iommu/io-pgtable-arm: Allow appropriate DMA API use

2015-08-05 Thread Will Deacon
Hi Laurent, On Tue, Aug 04, 2015 at 09:54:27PM +0100, Laurent Pinchart wrote: > On Tuesday 04 August 2015 15:56:42 Russell King - ARM Linux wrote: > > On Tue, Aug 04, 2015 at 03:47:13PM +0100, Robin Murphy wrote: > > > On 04/08/15 14:16, Laurent Pinchart wrote: > > >> This is what I believe to be

Re: [PATCH 05/13] iommu/io-pgtable-arm: Allow appropriate DMA API use

2015-08-04 Thread Laurent Pinchart
Hi Russell, On Tuesday 04 August 2015 15:56:42 Russell King - ARM Linux wrote: > On Tue, Aug 04, 2015 at 03:47:13PM +0100, Robin Murphy wrote: > > Hi Laurent, > > > > [ +RMK, as his patch is indirectly involved here ] > > > > On 04/08/15 14:16, Laurent Pinchart wrote: > >> This is what I believe

Re: [PATCH 05/13] iommu/io-pgtable-arm: Allow appropriate DMA API use

2015-08-04 Thread Russell King - ARM Linux
On Tue, Aug 04, 2015 at 03:47:13PM +0100, Robin Murphy wrote: > Hi Laurent, > > [ +RMK, as his patch is indirectly involved here ] > > On 04/08/15 14:16, Laurent Pinchart wrote: > >This is what I believe to be an API abuse. The dma_sync_single_for_device() > >API is meant to pass ownership of a b

Re: [PATCH 05/13] iommu/io-pgtable-arm: Allow appropriate DMA API use

2015-08-04 Thread Robin Murphy
Hi Laurent, [ +RMK, as his patch is indirectly involved here ] On 04/08/15 14:16, Laurent Pinchart wrote: Hi Will and Robin, Thank you for the patch. On Monday 03 August 2015 14:25:47 Will Deacon wrote: From: Robin Murphy Currently, users of the LPAE page table code are (ab)using dma_map_p

Re: [PATCH 05/13] iommu/io-pgtable-arm: Allow appropriate DMA API use

2015-08-04 Thread Laurent Pinchart
Hi Will and Robin, Thank you for the patch. On Monday 03 August 2015 14:25:47 Will Deacon wrote: > From: Robin Murphy > > Currently, users of the LPAE page table code are (ab)using dma_map_page() > as a means to flush page table updates for non-coherent IOMMUs. Since > from the CPU's point of v

[PATCH 05/13] iommu/io-pgtable-arm: Allow appropriate DMA API use

2015-08-03 Thread Will Deacon
From: Robin Murphy Currently, users of the LPAE page table code are (ab)using dma_map_page() as a means to flush page table updates for non-coherent IOMMUs. Since from the CPU's point of view, creating IOMMU page tables *is* passing DMA buffers to a device (the IOMMU's page table walker), there's