Re: [PATCH] drm/i915/pmu: Use existing uncore helper to read gpm_timestamp

[Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxxxxxxx>]

On 27/04/2022 01:35, Umesh Nerlige Ramappa wrote:
> Use intel_uncore_read64_2x32 to read upper and lower fields of the GPM
> timestamp.
>
> v2: Fix compile error
>
> Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@xxxxxxxxx>
> ---
>   .../gpu/drm/i915/gt/uc/intel_guc_submission.c   | 17 ++---------------
>   1 file changed, 2 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> index 61a6f2424e24..33e695adfd6a 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> @@ -1200,20 +1200,6 @@ static u32 gpm_timestamp_shift(struct intel_gt *gt)
>   	return 3 - shift;
>   }
>   
> -static u64 gpm_timestamp(struct intel_gt *gt)
> -{
> -	u32 lo, hi, old_hi, loop = 0;
> -
> -	hi = intel_uncore_read(gt->uncore, MISC_STATUS1);
> -	do {
> -		lo = intel_uncore_read(gt->uncore, MISC_STATUS0);
> -		old_hi = hi;
> -		hi = intel_uncore_read(gt->uncore, MISC_STATUS1);
> -	} while (old_hi != hi && loop++ < 2);
> -
> -	return ((u64)hi << 32) | lo;
> -}
> -
>   static void guc_update_pm_timestamp(struct intel_guc *guc, ktime_t *now)
>   {
>   	struct intel_gt *gt = guc_to_gt(guc);
> @@ -1223,7 +1209,8 @@ static void guc_update_pm_timestamp(struct intel_guc *guc, ktime_t *now)
>   	lockdep_assert_held(&guc->timestamp.lock);
>   
>   	gt_stamp_hi = upper_32_bits(guc->timestamp.gt_stamp);
> -	gpm_ts = gpm_timestamp(gt) >> guc->timestamp.shift;
> +	gpm_ts = intel_uncore_read64_2x32(gt->uncore, MISC_STATUS0,
> +					  MISC_STATUS1) >> guc->timestamp.shift;
>   	gt_stamp_lo = lower_32_bits(gpm_ts);
>   	*now = ktime_get();
>   

Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>

Regards,

Tvrtko