2011/6/16 Scott Jiang <scott.jiang.linux@xxxxxxxxx>: > 2011/6/16 Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>: >> Hello Scott, >> >>> Hi Marek and Laurent, >>> >>> I am working on v4l2 drivers for blackfin which is a no mmu soc. >>> I found videobuf allocate memory in mmap not reqbuf, so I turn to videobuf2. >>> But __setup_offsets() use plane offset to fill m.offset, which is >>> always 0 for single-planar buffer. >>> So pgoff in get_unmapped_area callback equals 0. >>> I only found uvc handled get_unmapped_area for no mmu system, but it >>> manages buffers itself. >>> I really want videobuf2 to manage buffers. Please give me some advice. >> >> I'm not really sure if I know the differences between mmu and no-mmu >> systems (from the device driver perspective). I assume that you are using >> videobuf2-vmalloc allocator. Note that memory allocators/managers are well >> separated from the videobuf2 logic. If it the current one doesn't serve you >> well you can make your own no-mmu allocator. Later once we identify all >> differences it might be merged with the standard one or left alone if the >> merge is not really possible or easy. >> >> Best regards >> -- >> Marek Szyprowski >> Samsung Poland R&D Center >> >> >> > > Hi Marek, > > I used dma-contig allocator. I mean if offset is 0, I must get actual > addr from this offset. hi, Scott if it is single plane, surely the offset is 0 for plane 0 what do you mean the actual addr ? > __find_plane_by_offset can do this. But it is an internal function. > I think there should be a function called vb2_get_unmapped_area to do > this in framework side. are you using soc_camera ? you can add your get_unmapped_area in soc_camera. if not, you can add it in your v4l2_file_operations ops, while still using videbuf2 to management your buffer. > > Regards, > Scott > -- > 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 > -- Best regards Kassey Application Processor Systems Engineering, Marvell Technology Group Ltd. Shanghai, China. -- 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
