[PATCH 1/3] drm/etnaviv: move debug register en-/disable into own function

[Philipp Zabel]

On Fr, 2024-06-28 at 12:47 +0200, Lucas Stach wrote:
> The next changes will introduce another place where the debug registers
> need to be en-/disabled. Split into separate functions, so we don't need
> to replicate the code there. Also allow those calls to nest, keeping
> the debug registers enabled until all callers don't need them any longer.
> 
> Signed-off-by: Lucas Stach <l.stach at pengutronix.de>
> ---
>  drivers/gpu/drm/etnaviv/etnaviv_gpu.c | 33 ++++++++++++++++++++-------
>  drivers/gpu/drm/etnaviv/etnaviv_gpu.h |  3 +++
>  2 files changed, 28 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
> index 7c7f97793ddd..ade6f7554706 100644
> --- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
> +++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
> @@ -471,6 +471,29 @@ static void etnaviv_hw_identify(struct etnaviv_gpu *gpu)
>  
>  	etnaviv_hw_specs(gpu);
>  }
> +void etnaviv_gpu_enable_debug_regs(struct etnaviv_gpu *gpu)
> +{
> +	u32 val;
> +
> +	if (atomic_inc_return(&gpu->dbg_ref) > 1)
> +		return;

This is a reference count, any reason not to use refcount_t?

> +
> +	val = gpu_read(gpu, VIVS_HI_CLOCK_CONTROL);
> +	val &= ~VIVS_HI_CLOCK_CONTROL_DISABLE_DEBUG_REGISTERS;
> +	gpu_write(gpu, VIVS_HI_CLOCK_CONTROL, val);

Does this need locking after patch 3, to avoid racing of
sync_point_perfmon_sample_pre/post() with etnaviv_sched_timedout_job()?

regards
Philipp