MT8195 has two H264 encoder cores, they have their own power-domains,
clocks, interrupts, register base. The two H264 encoder cores can work
together to achieve higher performance, it's a core mode called
frame-racing, one core has 4K@30fps performance, two cores can achieve
4K@60fps.
The two encoder core encoding process looks like this:
VENC Core0: frm#0....frm#2....frm#4....
VENC Core1: ..frm#1....frm#3....frm#5....
This series of patches are used to enable the two H264 encoder cores,
encoding process will be changed:
As-Is: Synchronous
V4L2_VIDIOC_QBUF#0 --> device_run(triger encoder) --> wait encoder IRQ -->
encoding done with result --> job_finish
V4l2_VIDIOC_QBUF#1 --> device_run(triger encoder) --> wait encoder IRQ -->
encoding done with result --> job_finish
...
To-Be: Asynchronous
V4L2_VIDIOC_QBUF#0 --> device_run(triger encoder) --> job_finish
..V4l2_VIDIOC_QBUF#1 --> device_run(triger encoder) --> job_finish
(venc core0 may encode done here, done the encoding result to client)
V4L2_VIDIOC_QBUF#2 --> device_run(triger encoder) --> job_finish.
There is no "wait encoder IRQ" synchronous call during frame-racing mode
encoding process, it can full use the two encoder cores to achieve higher
performance.