Hello, On Tuesday, April 26, 2011 4:10 PM Arnd Bergmann wrote: > On Friday 22 April 2011, Marek Szyprowski wrote: > > > * Create two codec devices in parallel and bind to both with your > > > driver, ideally splitting up the resources between the two > > > devices in a meaningful way. > > > > Video codec has only standard 2 resources - ioregs and irq, so there > > is not much left for such splitting. > > Ok, I see. > > > > None of them are extremely nice, but it's not that hard either. > > > You should probably prototype a few of these approaches to see > > > which one is the least ugly one. > > > > Ok. Today while iterating over the hardware requirements I noticed > > one more thing. Our codec hardware has one more, odd requirement for > > video buffers. The DMA addresses need to be aligned to 8KiB or 16KiB > > (depending on buffer type). Do you have any idea how this can be > > handled in a generic way? > > I don't think you can force the mappings to be aligned to that size > in the streaming mapping, but you should be able to just align inside > of dma_map_single etc and map a larger region. > > For the allocation functions (dma_alloc_coherent, dma_alloc_noncoherent), > using alloc_pages to allocate multiples of the size you need should > always give you aligned buffers because of the way that the underlying > buddy allocator works. Well, I thought about the alignment of the IOVA mapping. I will probably handle it with some additional archdata stuff. I've started hacking ARM dma-mapping interface to get support for dma-mapping-common.h and then to integrate with Samsung IOMMU driver. I hope to post the initial version before Linaro meeting in Budapest. Best regards -- Marek Szyprowski Samsung Poland R&D Center -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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