Re: [PATCH 04/17] drm/i915/cnl: Allow dynamic cdclk changes on CNL

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Thu, Jun 08, 2017 at 03:03:13PM -0700, Rodrigo Vivi wrote:
> All the low level cdclk bits are present, so let's add the required
> hooks to reconfigure cdclk on the fly.
> 
> v2: Rebase due to cnl_sanitize_cdclk()
> v3: Rebased by Rodrigo on top of Ville's cdclk rework.
> v4: Rebase moving cnl_calc_cdclk up to follow same order
>     as previous platforms.
> v2: Squash drm/i915/cnl: Adjust min pixel rate. to address
>     the current limitation where CDCLK cannot be set to 168MHz
>     if audio is used with 96MHz. (Imre)
> 
> Cc: Imre Deak <imre.deak@intel.com>
> Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
> 
> Cannonlake also needs to adjust the minimal pixel rate
> as gen9 platforms. Specially for the Azalia audio case.
> 
> Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
> Cc: Sanyog Kale <sanyog.r.kale@intel.com>
> Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_cdclk.c | 56 ++++++++++++++++++++++++++++++++++++--
>  1 file changed, 53 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_cdclk.c b/drivers/gpu/drm/i915/intel_cdclk.c
> index 35a1432..1d7cfc5 100644
> --- a/drivers/gpu/drm/i915/intel_cdclk.c
> +++ b/drivers/gpu/drm/i915/intel_cdclk.c
> @@ -1400,6 +1400,16 @@ void bxt_uninit_cdclk(struct drm_i915_private *dev_priv)
>  	bxt_set_cdclk(dev_priv, &cdclk_state);
>  }
>  
> +static int cnl_calc_cdclk(int max_pixclk)
> +{
> +	if (max_pixclk > 336000)
> +		return 528000;
> +	else if (max_pixclk > 168000)
> +		return 336000;
> +	else
> +		return 168000;
> +}
> +
>  static void cnl_cdclk_pll_update(struct drm_i915_private *dev_priv,
>  				 struct intel_cdclk_state *cdclk_state)
>  {
> @@ -1641,7 +1651,7 @@ void cnl_init_cdclk(struct drm_i915_private *dev_priv)
>  
>  	cdclk_state = dev_priv->cdclk.hw;
>  
> -	cdclk_state.cdclk = 168000;
> +	cdclk_state.cdclk = cnl_calc_cdclk(0);
>  	cdclk_state.vco = cnl_cdclk_pll_vco(dev_priv, cdclk_state.cdclk);
>  
>  	cnl_set_cdclk(dev_priv, &cdclk_state);
> @@ -1768,7 +1778,7 @@ static int intel_max_pixel_rate(struct drm_atomic_state *state)
>  
>  		pixel_rate = crtc_state->pixel_rate;
>  
> -		if (IS_BROADWELL(dev_priv) || IS_GEN9(dev_priv))
> +		if (IS_BROADWELL(dev_priv) || INTEL_GEN(dev_priv) >= 9)
>  			pixel_rate =
>  				bdw_adjust_min_pipe_pixel_rate(crtc_state,
>  							       pixel_rate);

I think you might also have to adjust some of the clock limits
within bdw_adjust_min_pipe_pixel_rate().

> @@ -1929,6 +1939,40 @@ static int bxt_modeset_calc_cdclk(struct drm_atomic_state *state)
>  	return 0;
>  }
>  
> +static int cnl_modeset_calc_cdclk(struct drm_atomic_state *state)
> +{
> +	struct drm_i915_private *dev_priv = to_i915(state->dev);
> +	struct intel_atomic_state *intel_state =
> +		to_intel_atomic_state(state);
> +	int max_pixclk = intel_max_pixel_rate(state);
> +	int cdclk, vco;
> +
> +	cdclk = cnl_calc_cdclk(max_pixclk);
> +	vco = cnl_cdclk_pll_vco(dev_priv, cdclk);
> +
> +	if (cdclk > dev_priv->max_cdclk_freq) {
> +		DRM_DEBUG_KMS("requested cdclk (%d kHz) exceeds max (%d kHz)\n",
> +			      cdclk, dev_priv->max_cdclk_freq);
> +		return -EINVAL;
> +	}
> +
> +	intel_state->cdclk.logical.vco = vco;
> +	intel_state->cdclk.logical.cdclk = cdclk;
> +
> +	if (!intel_state->active_crtcs) {
> +		cdclk = cnl_calc_cdclk(0);
> +		vco = cnl_cdclk_pll_vco(dev_priv, cdclk);
> +
> +		intel_state->cdclk.actual.vco = vco;
> +		intel_state->cdclk.actual.cdclk = cdclk;
> +	} else {
> +		intel_state->cdclk.actual =
> +			intel_state->cdclk.logical;
> +	}
> +
> +	return 0;
> +}
> +
>  static int intel_compute_max_dotclk(struct drm_i915_private *dev_priv)
>  {
>  	int max_cdclk_freq = dev_priv->max_cdclk_freq;
> @@ -1960,7 +2004,9 @@ static int intel_compute_max_dotclk(struct drm_i915_private *dev_priv)
>   */
>  void intel_update_max_cdclk(struct drm_i915_private *dev_priv)
>  {
> -	if (IS_GEN9_BC(dev_priv)) {
> +	if (IS_CANNONLAKE(dev_priv)) {
> +		dev_priv->max_cdclk_freq = 528000;
> +	} else if (IS_GEN9_BC(dev_priv)) {
>  		u32 limit = I915_READ(SKL_DFSM) & SKL_DFSM_CDCLK_LIMIT_MASK;
>  		int max_cdclk, vco;
>  
> @@ -2157,6 +2203,10 @@ void intel_init_cdclk_hooks(struct drm_i915_private *dev_priv)
>  		dev_priv->display.set_cdclk = skl_set_cdclk;
>  		dev_priv->display.modeset_calc_cdclk =
>  			skl_modeset_calc_cdclk;
> +	} else if (IS_CANNONLAKE(dev_priv)) {
> +		dev_priv->display.set_cdclk = cnl_set_cdclk;
> +		dev_priv->display.modeset_calc_cdclk =
> +			cnl_modeset_calc_cdclk;
>  	}
>  
>  	if (IS_CANNONLAKE(dev_priv))
> -- 
> 1.9.1

-- 
Ville Syrjälä
Intel OTC
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