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media: videodev2.h: add v4l2_timeval_to_ns inline function
We want to be able to uniquely identify buffers for stateless codecs. The internal timestamp (a u64) as stored internally in the kernel is a suitable candidate for that, but in struct v4l2_buffer it is represented as a struct timeval. Add a v4l2_timeval_to_ns() function that converts the struct timeval into a u64 in the same way that the kernel does. This makes it possible to use this u64 elsewhere as a unique identifier of the buffer. Since timestamps are also copied from the output buffer to the corresponding capture buffer(s) by M2M devices, the u64 can be used to refer to both output and capture buffers. The plan is that in the future we redesign struct v4l2_buffer and use u64 for the timestamp instead of a struct timeval (which has lots of problems with 32 vs 64 bit and y2038 layout changes), and then there is no more need to use this function. Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
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@ -973,6 +973,18 @@ struct v4l2_buffer {
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};
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};
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/**
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* v4l2_timeval_to_ns - Convert timeval to nanoseconds
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* @ts: pointer to the timeval variable to be converted
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*
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* Returns the scalar nanosecond representation of the timeval
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* parameter.
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*/
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static inline __u64 v4l2_timeval_to_ns(const struct timeval *tv)
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{
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return (__u64)tv->tv_sec * 1000000000ULL + tv->tv_usec * 1000;
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}
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/* Flags for 'flags' field */
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/* Buffer is mapped (flag) */
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#define V4L2_BUF_FLAG_MAPPED 0x00000001
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