[Intel-gfx] [PATCH 1/2] drm/i915/pmu: Use functions common with sysfs to read actual freq

Tvrtko Ursulin tvrtko.ursulin at linux.intel.com
Wed Mar 15 09:43:30 UTC 2023


On 10/03/2023 00:59, Ashutosh Dixit wrote:
> Expose intel_rps_read_actual_frequency_fw to read the actual freq without
> taking forcewake for use by PMU. The code is refactored to use a common set
> of functions across sysfs and PMU. Using common functions with sysfs in PMU
> solves the issues of missing support for MTL and missing support for older
> generations (prior to Gen6). It also future proofs the PMU where sometimes
> code has been updated for sysfs and PMU has been missed.
> 
> v2: Remove runtime_pm_if_in_use from read_actual_frequency_fw (Tvrtko)
> 
> Fixes: 22009b6dad66 ("drm/i915/mtl: Modify CAGF functions for MTL")
> Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/8280
> Signed-off-by: Ashutosh Dixit <ashutosh.dixit at intel.com>
> ---
>   drivers/gpu/drm/i915/gt/intel_rps.c | 34 ++++++++++++++++-------------
>   drivers/gpu/drm/i915/gt/intel_rps.h |  2 +-
>   drivers/gpu/drm/i915/i915_pmu.c     | 10 ++++-----
>   3 files changed, 24 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gt/intel_rps.c b/drivers/gpu/drm/i915/gt/intel_rps.c
> index 4d0dc9de23f9..9d9ac35691fc 100644
> --- a/drivers/gpu/drm/i915/gt/intel_rps.c
> +++ b/drivers/gpu/drm/i915/gt/intel_rps.c
> @@ -2046,16 +2046,6 @@ void intel_rps_sanitize(struct intel_rps *rps)
>   		rps_disable_interrupts(rps);
>   }
>   
> -u32 intel_rps_read_rpstat_fw(struct intel_rps *rps)
> -{
> -	struct drm_i915_private *i915 = rps_to_i915(rps);
> -	i915_reg_t rpstat;
> -
> -	rpstat = (GRAPHICS_VER(i915) >= 12) ? GEN12_RPSTAT1 : GEN6_RPSTAT1;
> -
> -	return intel_uncore_read_fw(rps_to_gt(rps)->uncore, rpstat);
> -}
> -
>   u32 intel_rps_read_rpstat(struct intel_rps *rps)
>   {
>   	struct drm_i915_private *i915 = rps_to_i915(rps);
> @@ -2089,10 +2079,11 @@ u32 intel_rps_get_cagf(struct intel_rps *rps, u32 rpstat)
>   	return cagf;
>   }
>   
> -static u32 read_cagf(struct intel_rps *rps)
> +static u32 __read_cagf(struct intel_rps *rps, bool take_fw)
>   {
>   	struct drm_i915_private *i915 = rps_to_i915(rps);
>   	struct intel_uncore *uncore = rps_to_uncore(rps);
> +	i915_reg_t r = INVALID_MMIO_REG;
>   	u32 freq;
>   
>   	/*
> @@ -2100,22 +2091,30 @@ static u32 read_cagf(struct intel_rps *rps)
>   	 * registers will return 0 freq when GT is in RC6
>   	 */
>   	if (GRAPHICS_VER_FULL(i915) >= IP_VER(12, 70)) {
> -		freq = intel_uncore_read(uncore, MTL_MIRROR_TARGET_WP1);
> +		r = MTL_MIRROR_TARGET_WP1;
>   	} else if (GRAPHICS_VER(i915) >= 12) {
> -		freq = intel_uncore_read(uncore, GEN12_RPSTAT1);
> +		r = GEN12_RPSTAT1;
>   	} else if (IS_VALLEYVIEW(i915) || IS_CHERRYVIEW(i915)) {
>   		vlv_punit_get(i915);
>   		freq = vlv_punit_read(i915, PUNIT_REG_GPU_FREQ_STS);
>   		vlv_punit_put(i915);
> +		goto exit;

Alternatively you could avoid the goto by making the read below 
conditional on r being set. One more conditional though for avoiding 
gotos.. up to you.

>   	} else if (GRAPHICS_VER(i915) >= 6) {
> -		freq = intel_uncore_read(uncore, GEN6_RPSTAT1);
> +		r = GEN6_RPSTAT1;
>   	} else {
> -		freq = intel_uncore_read(uncore, MEMSTAT_ILK);
> +		r = MEMSTAT_ILK;
>   	}
>   
> +	freq = take_fw ? intel_uncore_read(uncore, r) : intel_uncore_read_fw(uncore, r);
> +exit:
>   	return intel_rps_get_cagf(rps, freq);
>   }
>   
> +static u32 read_cagf(struct intel_rps *rps)
> +{
> +	return __read_cagf(rps, true);
> +}

There is only one caller so up to you if you think a helper is needed or 
not.

> +
>   u32 intel_rps_read_actual_frequency(struct intel_rps *rps)
>   {
>   	struct intel_runtime_pm *rpm = rps_to_uncore(rps)->rpm;
> @@ -2128,6 +2127,11 @@ u32 intel_rps_read_actual_frequency(struct intel_rps *rps)
>   	return freq;
>   }
>   
> +u32 intel_rps_read_actual_frequency_fw(struct intel_rps *rps)
> +{
> +	return intel_gpu_freq(rps, __read_cagf(rps, false));
> +}
> +
>   u32 intel_rps_read_punit_req(struct intel_rps *rps)
>   {
>   	struct intel_uncore *uncore = rps_to_uncore(rps);
> diff --git a/drivers/gpu/drm/i915/gt/intel_rps.h b/drivers/gpu/drm/i915/gt/intel_rps.h
> index c622962c6bef..2d5b3ef58606 100644
> --- a/drivers/gpu/drm/i915/gt/intel_rps.h
> +++ b/drivers/gpu/drm/i915/gt/intel_rps.h
> @@ -39,6 +39,7 @@ int intel_gpu_freq(struct intel_rps *rps, int val);
>   int intel_freq_opcode(struct intel_rps *rps, int val);
>   u32 intel_rps_get_cagf(struct intel_rps *rps, u32 rpstat1);
>   u32 intel_rps_read_actual_frequency(struct intel_rps *rps);
> +u32 intel_rps_read_actual_frequency_fw(struct intel_rps *rps);
>   u32 intel_rps_get_requested_frequency(struct intel_rps *rps);
>   u32 intel_rps_get_min_frequency(struct intel_rps *rps);
>   u32 intel_rps_get_min_raw_freq(struct intel_rps *rps);
> @@ -52,7 +53,6 @@ u32 intel_rps_get_rpn_frequency(struct intel_rps *rps);
>   u32 intel_rps_read_punit_req(struct intel_rps *rps);
>   u32 intel_rps_read_punit_req_frequency(struct intel_rps *rps);
>   u32 intel_rps_read_rpstat(struct intel_rps *rps);
> -u32 intel_rps_read_rpstat_fw(struct intel_rps *rps);
>   void gen6_rps_get_freq_caps(struct intel_rps *rps, struct intel_rps_freq_caps *caps);
>   void intel_rps_raise_unslice(struct intel_rps *rps);
>   void intel_rps_lower_unslice(struct intel_rps *rps);
> diff --git a/drivers/gpu/drm/i915/i915_pmu.c b/drivers/gpu/drm/i915/i915_pmu.c
> index a76c5ce9513d..7ece883a7d95 100644
> --- a/drivers/gpu/drm/i915/i915_pmu.c
> +++ b/drivers/gpu/drm/i915/i915_pmu.c
> @@ -392,14 +392,12 @@ frequency_sample(struct intel_gt *gt, unsigned int period_ns)
>   		 * case we assume the system is running at the intended
>   		 * frequency. Fortunately, the read should rarely fail!
>   		 */
> -		val = intel_rps_read_rpstat_fw(rps);
> -		if (val)
> -			val = intel_rps_get_cagf(rps, val);

I think you can un-export this one now.

With that looks okay to me, with or without the other stuff:

Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>

Regards,

Tvrtko

> -		else
> -			val = rps->cur_freq;
> +		val = intel_rps_read_actual_frequency_fw(rps);
> +		if (!val)
> +			val = intel_gpu_freq(rps, rps->cur_freq);
>   
>   		add_sample_mult(&pmu->sample[__I915_SAMPLE_FREQ_ACT],
> -				intel_gpu_freq(rps, val), period_ns / 1000);
> +				val, period_ns / 1000);
>   	}
>   
>   	if (pmu->enable & config_mask(I915_PMU_REQUESTED_FREQUENCY)) {


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