Re: [PATCH 3/3] drm/i915/icl: use previous pll hw readout

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

On Thu, Mar 21, 2019 at 03:02:57PM -0700, Lucas De Marchi wrote:
> By the time icl_ddi_clock_get() is called we've just got the hw state
> from the pll registers. We don't need to read them again: we can rather
> reuse what was cached in the dpll_hw_state.
> 
> Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_ddi.c | 39 +++++++++++++++-----------------
>  1 file changed, 18 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> index fe52af9fa4aa..0ea5a97dfe9d 100644
> --- a/drivers/gpu/drm/i915/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/intel_ddi.c
> @@ -1372,26 +1372,20 @@ static int icl_calc_tbt_pll_link(struct drm_i915_private *dev_priv,
>  	}
>  }
>  
> -static int icl_calc_mg_pll_link(struct drm_i915_private *dev_priv,
> -				enum port port)
> +
> +static int icl_calc_mg_pll_link(struct intel_dpll_hw_state *state, u32 refclk)

Inconsistent with the cnl variant.

>  {
> -	enum tc_port tc_port = intel_port_to_tc(dev_priv, port);
> -	u32 mg_pll_div0, mg_clktop_hsclkctl;
> -	u32 m1, m2_int, m2_frac, div1, div2, refclk;
> +	u32 m1, m2_int, m2_frac, div1, div2;
>  	u64 tmp;
>  
> -	refclk = dev_priv->cdclk.hw.ref;
> -
> -	mg_pll_div0 = I915_READ(MG_PLL_DIV0(tc_port));
> -	mg_clktop_hsclkctl = I915_READ(MG_CLKTOP2_HSCLKCTL(tc_port));
> -
> -	m1 = I915_READ(MG_PLL_DIV1(tc_port)) & MG_PLL_DIV1_FBPREDIV_MASK;
> -	m2_int = mg_pll_div0 & MG_PLL_DIV0_FBDIV_INT_MASK;
> -	m2_frac = (mg_pll_div0 & MG_PLL_DIV0_FRACNEN_H) ?
> -		  (mg_pll_div0 & MG_PLL_DIV0_FBDIV_FRAC_MASK) >>
> +	m1 = state->mg_pll_div1 & MG_PLL_DIV1_FBPREDIV_MASK;
> +	m2_int = state->mg_pll_div0 & MG_PLL_DIV0_FBDIV_INT_MASK;
> +	m2_frac = (state->mg_pll_div0 & MG_PLL_DIV0_FRACNEN_H) ?
> +		  (state->mg_pll_div0 & MG_PLL_DIV0_FBDIV_FRAC_MASK) >>
>  		  MG_PLL_DIV0_FBDIV_FRAC_SHIFT : 0;
>  
> -	switch (mg_clktop_hsclkctl & MG_CLKTOP2_HSCLKCTL_HSDIV_RATIO_MASK) {
> +	switch (state->mg_clktop2_hsclkctl &
> +		MG_CLKTOP2_HSCLKCTL_HSDIV_RATIO_MASK) {
>  	case MG_CLKTOP2_HSCLKCTL_HSDIV_RATIO_2:
>  		div1 = 2;
>  		break;
> @@ -1405,12 +1399,14 @@ static int icl_calc_mg_pll_link(struct drm_i915_private *dev_priv,
>  		div1 = 7;
>  		break;
>  	default:
> -		MISSING_CASE(mg_clktop_hsclkctl);
> +		MISSING_CASE(state->mg_clktop2_hsclkctl);
>  		return 0;
>  	}
>  
> -	div2 = (mg_clktop_hsclkctl & MG_CLKTOP2_HSCLKCTL_DSDIV_RATIO_MASK) >>
> +	div2 = (state->mg_clktop2_hsclkctl &
> +		MG_CLKTOP2_HSCLKCTL_DSDIV_RATIO_MASK) >>
>  		MG_CLKTOP2_HSCLKCTL_DSDIV_RATIO_SHIFT;
> +
>  	/* div2 value of 0 is same as 1 means no div */
>  	if (div2 == 0)
>  		div2 = 1;
> @@ -1457,9 +1453,6 @@ static void icl_ddi_clock_get(struct intel_encoder *encoder,
>  	struct intel_dpll_hw_state *state;
>  	enum port port = encoder->port;
>  	int link_clock = 0;
> -	u32 pll_id;
> -
> -	pll_id = intel_get_shared_dpll_id(dev_priv, pipe_config->shared_dpll);
>  
>  	/* For DDI ports we always use a shared PLL. */
>  	if (WARN_ON(!pipe_config->shared_dpll))
> @@ -1470,10 +1463,14 @@ static void icl_ddi_clock_get(struct intel_encoder *encoder,
>  	if (intel_port_is_combophy(dev_priv, port)) {
>  		link_clock = cnl_calc_wrpll_link(dev_priv, state);
>  	} else {
> +		enum intel_dpll_id pll_id = intel_get_shared_dpll_id(dev_priv,
> +				pipe_config->shared_dpll);
> +
>  		if (pll_id == DPLL_ID_ICL_TBTPLL)
>  			link_clock = icl_calc_tbt_pll_link(dev_priv, port);
>  		else
> -			link_clock = icl_calc_mg_pll_link(dev_priv, port);
> +			link_clock = icl_calc_mg_pll_link(
> +					state, dev_priv->cdclk.hw.ref);
>  	}
>  
>  end:
> -- 
> 2.20.1

-- 
Ville Syrjälä
Intel
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