Messages in this thread | | | From | dillon min <> | Date | Wed, 10 Jun 2020 10:24:10 +0800 | Subject | Re: [PATCH 2/2] arm-nommu: Add use_reserved_mem() to check if device support reserved memory |
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Hi Vladimir,
I tested your changes, it's working fine on stm32f429-disco(armv7m, without cache) board. you can submit a separate patch for dma-direct support on non-mmu platform, i will drop mine.
thanks.
best regards.
Dillon, On Wed, Jun 10, 2020 at 1:34 AM Christoph Hellwig <hch@lst.de> wrote: > > On Tue, Jun 09, 2020 at 05:25:04PM +0100, Vladimir Murzin wrote: > > Even though commit mentions ARM, I do not see how mmap would continue > > to work for NOMMU with dma-direct. ARM NOMMU needs it's own DMA operations > > only in cases where caches are implemented or active, in other cases it > > fully relies on dma-direct. > > > It looks to me that we either should provide NOMMU variant for mmap in > > dma/direct or (carefully) fix dma/mapping. > > I think dma-direct is the right place, the common helpers in > dma/mapping.c are basically the red headed stepchilds for misc > IOMMU drivers not covered by dma-iommu only.
Yes, thanks Christoph's input.
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