Re: no mmu on videobuf2
2011/6/16 Marek Szyprowski m.szyprow...@samsung.com: 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 RD Center Hi Marek, I used dma-contig allocator. I mean if offset is 0, I must get actual addr from this offset. __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. Regards, Scott -- To unsubscribe from this list: send the line unsubscribe linux-media in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: no mmu on videobuf2
2011/6/16 Scott Jiang scott.jiang.li...@gmail.com: 2011/6/16 Marek Szyprowski m.szyprow...@samsung.com: 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 RD 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 majord...@vger.kernel.org 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 majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: no mmu on videobuf2
Hi Kassey, 2011/6/16 Kassey Lee kassey1...@gmail.com: 2011/6/16 Scott Jiang scott.jiang.li...@gmail.com: 2011/6/16 Marek Szyprowski m.szyprow...@samsung.com: 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 RD 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 yes, it is absolutely right. what do you mean the actual addr ? I should return virtual address of the buffer in get_unmapped_area callback. __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. yes, I have added this method, just copy __find_plane_by_offset code. But it is ugly, it should have a vb2_get_unmapped_area like vb2_mmap. These two operations are called by one system call, so they should have a uniform looks. Regards, Scott -- To unsubscribe from this list: send the line unsubscribe linux-media in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
RE: no mmu on videobuf2
Hello, On Thursday, June 16, 2011 9:57 AM Scott Jiang wrote: (snipped) 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 yes, it is absolutely right. what do you mean the actual addr ? I should return virtual address of the buffer in get_unmapped_area callback. __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. yes, I have added this method, just copy __find_plane_by_offset code. But it is ugly, it should have a vb2_get_unmapped_area like vb2_mmap. These two operations are called by one system call, so they should have a uniform looks. If videobuf2-core and its memory allocator interface lacks some operations that are essential for no-mmu systems, please just add them. Frankly I have no experience with Linux no-mmu systems, so I might have missed something that is required for no-mmu case. Best regards -- Marek Szyprowski Samsung Poland RD Center -- To unsubscribe from this list: send the line unsubscribe linux-media in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: no mmu on videobuf2
Hi Scott, On Thursday 16 June 2011 09:57:05 Scott Jiang wrote: 2011/6/16 Kassey Lee kassey1...@gmail.com: 2011/6/16 Scott Jiang scott.jiang.li...@gmail.com: 2011/6/16 Marek Szyprowski m.szyprow...@samsung.com: 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. I used dma-contig allocator. I mean if offset is 0, I must get actual addr from this offset. if it is single plane, surely the offset is 0 for plane 0 yes, it is absolutely right. what do you mean the actual addr ? I should return virtual address of the buffer in get_unmapped_area callback. __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. yes, I have added this method, just copy __find_plane_by_offset code. But it is ugly, it should have a vb2_get_unmapped_area like vb2_mmap. These two operations are called by one system call, so they should have a uniform looks. I agree with that. get_unmapped_area is a file operation and should be implemented using a videobuf2 helper, like vb2_mmap. -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line unsubscribe linux-media in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
RE: no mmu on videobuf2
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 RD Center -- To unsubscribe from this list: send the line unsubscribe linux-media in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
