Re: [PATCH 28/24] drm/i915/icl: implement DVFS for ICL

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Thu, May 24, 2018 at 04:42:39PM -0700, Paulo Zanoni wrote:
> ICL DVFS is almost the same as CNL, except for the CDCLK/DDICLK
> table. Implement it just like CNL does.
> 
> References: commit 48469eced282 ("drm/i915: Use cdclk_state->voltage
>  on CNL")
> References: commit 53e9bf5e8159 ("drm/i915: Adjust system agent
>  voltage on CNL if required by DDI ports")
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>

Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

> ---
>  drivers/gpu/drm/i915/intel_cdclk.c | 46 +++++++++++++++++++++++++++++++++++---
>  drivers/gpu/drm/i915/intel_ddi.c   |  2 ++
>  2 files changed, 45 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_cdclk.c b/drivers/gpu/drm/i915/intel_cdclk.c
> index 704ddb4d3ca7..642f1e542a62 100644
> --- a/drivers/gpu/drm/i915/intel_cdclk.c
> +++ b/drivers/gpu/drm/i915/intel_cdclk.c
> @@ -1861,11 +1861,35 @@ static void icl_set_cdclk(struct drm_i915_private *dev_priv,
>  			      skl_cdclk_decimal(cdclk));
>  
>  	mutex_lock(&dev_priv->pcu_lock);
> -	/* TODO: add proper DVFS support. */
> -	sandybridge_pcode_write(dev_priv, SKL_PCODE_CDCLK_CONTROL, 2);
> +	sandybridge_pcode_write(dev_priv, SKL_PCODE_CDCLK_CONTROL,
> +				cdclk_state->voltage_level);
>  	mutex_unlock(&dev_priv->pcu_lock);
>  
>  	intel_update_cdclk(dev_priv);
> +
> +	/*
> +	 * Can't read out the voltage level :(
> +	 * Let's just assume everything is as expected.
> +	 */
> +	dev_priv->cdclk.hw.voltage_level = cdclk_state->voltage_level;
> +}
> +
> +static u8 icl_calc_voltage_level(int cdclk)
> +{
> +	switch (cdclk) {
> +	case 50000:
> +	case 307200:
> +	case 312000:
> +		return 0;
> +	case 556800:
> +	case 552000:
> +		return 1;
> +	default:
> +		MISSING_CASE(cdclk);
> +	case 652800:
> +	case 648000:
> +		return 2;
> +	}
>  }
>  
>  static void icl_get_cdclk(struct drm_i915_private *dev_priv,
> @@ -1899,7 +1923,7 @@ static void icl_get_cdclk(struct drm_i915_private *dev_priv,
>  		 */
>  		cdclk_state->vco = 0;
>  		cdclk_state->cdclk = cdclk_state->bypass;
> -		return;
> +		goto out;
>  	}
>  
>  	cdclk_state->vco = (val & BXT_DE_PLL_RATIO_MASK) * cdclk_state->ref;
> @@ -1908,6 +1932,14 @@ static void icl_get_cdclk(struct drm_i915_private *dev_priv,
>  	WARN_ON((val & BXT_CDCLK_CD2X_DIV_SEL_MASK) != 0);
>  
>  	cdclk_state->cdclk = cdclk_state->vco / 2;
> +
> +out:
> +	/*
> +	 * Can't read this out :( Let's assume it's
> +	 * at least what the CDCLK frequency requires.
> +	 */
> +	cdclk_state->voltage_level =
> +		icl_calc_voltage_level(cdclk_state->cdclk);
>  }
>  
>  /**
> @@ -1950,6 +1982,8 @@ void icl_init_cdclk(struct drm_i915_private *dev_priv)
>  	sanitized_state.cdclk = icl_calc_cdclk(0, sanitized_state.ref);
>  	sanitized_state.vco = icl_calc_cdclk_pll_vco(dev_priv,
>  						     sanitized_state.cdclk);
> +	sanitized_state.voltage_level =
> +				icl_calc_voltage_level(sanitized_state.cdclk);
>  
>  	icl_set_cdclk(dev_priv, &sanitized_state);
>  }
> @@ -1967,6 +2001,7 @@ void icl_uninit_cdclk(struct drm_i915_private *dev_priv)
>  
>  	cdclk_state.cdclk = cdclk_state.bypass;
>  	cdclk_state.vco = 0;
> +	cdclk_state.voltage_level = icl_calc_voltage_level(cdclk_state.cdclk);
>  
>  	icl_set_cdclk(dev_priv, &cdclk_state);
>  }
> @@ -2470,6 +2505,9 @@ static int icl_modeset_calc_cdclk(struct drm_atomic_state *state)
>  
>  	intel_state->cdclk.logical.vco = vco;
>  	intel_state->cdclk.logical.cdclk = cdclk;
> +	intel_state->cdclk.logical.voltage_level =
> +		max(icl_calc_voltage_level(cdclk),
> +		    cnl_compute_min_voltage_level(intel_state));
>  
>  	if (!intel_state->active_crtcs) {
>  		cdclk = icl_calc_cdclk(0, ref);
> @@ -2477,6 +2515,8 @@ static int icl_modeset_calc_cdclk(struct drm_atomic_state *state)
>  
>  		intel_state->cdclk.actual.vco = vco;
>  		intel_state->cdclk.actual.cdclk = cdclk;
> +		intel_state->cdclk.actual.voltage_level =
> +			icl_calc_voltage_level(cdclk);
>  	} else {
>  		intel_state->cdclk.actual = intel_state->cdclk.logical;
>  	}
> diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> index 610c2d7d499c..6cdcbf9bf098 100644
> --- a/drivers/gpu/drm/i915/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/intel_ddi.c
> @@ -3073,6 +3073,8 @@ void intel_ddi_compute_min_voltage_level(struct drm_i915_private *dev_priv,
>  {
>  	if (IS_CANNONLAKE(dev_priv) && crtc_state->port_clock > 594000)
>  		crtc_state->min_voltage_level = 2;
> +	else if (IS_ICELAKE(dev_priv) && crtc_state->port_clock > 594000)
> +		crtc_state->min_voltage_level = 1;
>  }
>  
>  void intel_ddi_get_config(struct intel_encoder *encoder,
> -- 
> 2.14.3
> 
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