Re: [PATCH v4] drm/panthor: Add DEV_QUERY_TIMESTAMP_INFO dev query

[Boris Brezillon <boris.brezillon@collabora.com>]

On Wed, 4 Sep 2024 12:19:11 +0200
Boris Brezillon <boris.brezillon@collabora.com> wrote:

> On Fri, 30 Aug 2024 10:03:50 +0200
> Mary Guillemard <mary.guillemard@collabora.com> wrote:
> 
> > Expose timestamp information supported by the GPU with a new device
> > query.
> > 
> > Mali uses an external timer as GPU system time. On ARM, this is wired to
> > the generic arch timer so we wire cntfrq_el0 as device frequency.
> > 
> > This new uAPI will be used in Mesa to implement timestamp queries and
> > VK_KHR_calibrated_timestamps.
> > 
> > Since this extends the uAPI and because userland needs a way to advertise
> > those features conditionally, this also bumps the driver minor version.
> > 
> > v2:
> > - Rewrote to use GPU timestamp register
> > - Added timestamp_offset to drm_panthor_timestamp_info
> > - Add missing include for arch_timer_get_cntfrq
> > - Rework commit message
> > 
> > v3:
> > - Add panthor_gpu_read_64bit_counter
> > - Change panthor_gpu_read_timestamp to use
> >   panthor_gpu_read_64bit_counter
> > 
> > v4:
> > - Fix multiple typos in uAPI documentation
> > - Mention behavior when the timestamp frequency is unknown
> > - Use u64 instead of unsigned long long
> >   for panthor_gpu_read_timestamp
> > - Apply r-b from Mihail
> > 
> > Signed-off-by: Mary Guillemard <mary.guillemard@collabora.com>
> > Reviewed-by: Mihail Atanassov <mihail.atanassov@arm.com>  
> 
> Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>

Queued to drm-misc-next.