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. Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
