[PATCH v4 1/2] dma-fence: allow signaling drivers to set fence timestamp

[John Stultz]

On Fri, Jan 15, 2021 at 4:31 PM Veera Sundaram Sankaran
<veeras at codeaurora.org> wrote:
>
> Some drivers have hardware capability to get the precise HW timestamp
> of certain events based on which the fences are triggered. The delta
> between the event HW timestamp & current HW reference timestamp can
> be used to calculate the timestamp in kernel's CLOCK_MONOTONIC time
> domain. This allows it to set accurate timestamp factoring out any
> software and IRQ latencies. Add a timestamp variant of fence signal
> function, dma_fence_signal_timestamp to allow drivers to update the
> precise timestamp for fences.
>
> Changes in v2:
> - Add a new fence signal variant instead of modifying fence struct
>
> Changes in v3:
> - Add timestamp domain information to commit-text and
> dma_fence_signal_timestamp documentation
>
> Signed-off-by: Veera Sundaram Sankaran <veeras at codeaurora.org>
> ---
>  drivers/dma-buf/dma-fence.c | 70 ++++++++++++++++++++++++++++++++++++++++-----
>  include/linux/dma-fence.h   |  3 ++
>  2 files changed, 66 insertions(+), 7 deletions(-)

Thanks for respinning this!

Reviewed-by: John Stultz <john.stultz at linaro.org>

-john