[Intel-gfx] [PATCH 1/3] drm/i915/skl: use previous pll hw readout

[Ville Syrjälä]

On Thu, Mar 21, 2019 at 03:02:55PM -0700, Lucas De Marchi wrote:
> By the time skl_ddi_clock_get() is called - and thus
> skl_calc_wrpll_link() - 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 at intel.com>
> ---
>  drivers/gpu/drm/i915/intel_ddi.c | 49 ++++++++++++++------------------
>  1 file changed, 22 insertions(+), 27 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> index 933df3a57a8a..644541924208 100644
> --- a/drivers/gpu/drm/i915/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/intel_ddi.c
> @@ -1240,24 +1240,15 @@ static int hsw_ddi_calc_wrpll_link(struct drm_i915_private *dev_priv,
>  	return (refclk * n * 100) / (p * r);
>  }
>  
> -static int skl_calc_wrpll_link(struct drm_i915_private *dev_priv,
> -			       enum intel_dpll_id pll_id)
> +static int skl_calc_wrpll_link(struct intel_dpll_hw_state *state)

const

And please call it pll_state or something like that. Bonus points for
unifying the naming convention elsewhere as well.

>  {
> -	i915_reg_t cfgcr1_reg, cfgcr2_reg;
> -	u32 cfgcr1_val, cfgcr2_val;
>  	u32 p0, p1, p2, dco_freq;
>  
> -	cfgcr1_reg = DPLL_CFGCR1(pll_id);
> -	cfgcr2_reg = DPLL_CFGCR2(pll_id);
> +	p0 = state->cfgcr2 & DPLL_CFGCR2_PDIV_MASK;
> +	p2 = state->cfgcr2 & DPLL_CFGCR2_KDIV_MASK;
>  
> -	cfgcr1_val = I915_READ(cfgcr1_reg);
> -	cfgcr2_val = I915_READ(cfgcr2_reg);
> -
> -	p0 = cfgcr2_val & DPLL_CFGCR2_PDIV_MASK;
> -	p2 = cfgcr2_val & DPLL_CFGCR2_KDIV_MASK;
> -
> -	if (cfgcr2_val &  DPLL_CFGCR2_QDIV_MODE(1))
> -		p1 = (cfgcr2_val & DPLL_CFGCR2_QDIV_RATIO_MASK) >> 8;
> +	if (state->cfgcr2 &  DPLL_CFGCR2_QDIV_MODE(1))
> +		p1 = (state->cfgcr2 & DPLL_CFGCR2_QDIV_RATIO_MASK) >> 8;
>  	else
>  		p1 = 1;
>  
> @@ -1292,10 +1283,10 @@ static int skl_calc_wrpll_link(struct drm_i915_private *dev_priv,
>  		break;
>  	}
>  
> -	dco_freq = (cfgcr1_val & DPLL_CFGCR1_DCO_INTEGER_MASK) * 24 * 1000;
> +	dco_freq = (state->cfgcr1 & DPLL_CFGCR1_DCO_INTEGER_MASK) * 24 * 1000;
>  
> -	dco_freq += (((cfgcr1_val & DPLL_CFGCR1_DCO_FRACTION_MASK) >> 9) * 24 *
> -		1000) / 0x8000;
> +	dco_freq += (((state->cfgcr1 & DPLL_CFGCR1_DCO_FRACTION_MASK) >> 9)
> +		     * 24 * 1000) / 0x8000;
>  
>  	if (WARN_ON(p0 == 0 || p1 == 0 || p2 == 0))
>  		return 0;
> @@ -1546,20 +1537,23 @@ static void cnl_ddi_clock_get(struct intel_encoder *encoder,
>  static void skl_ddi_clock_get(struct intel_encoder *encoder,
>  				struct intel_crtc_state *pipe_config)
>  {
> -	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> +	struct intel_dpll_hw_state *state;
>  	int link_clock = 0;
> -	u32 dpll_ctl1;
> -	enum intel_dpll_id pll_id;
>  
> -	pll_id = intel_get_shared_dpll_id(dev_priv, pipe_config->shared_dpll);
> -
> -	dpll_ctl1 = I915_READ(DPLL_CTRL1);
> +	/* For DDI ports we always use a shared PLL. */
> +	if (WARN_ON(!pipe_config->shared_dpll))
> +		goto end;

return 0 will do.

Or maybe eliminate these entirely. I don't see these checks as
particularly useful.

>  
> -	if (dpll_ctl1 & DPLL_CTRL1_HDMI_MODE(pll_id)) {
> -		link_clock = skl_calc_wrpll_link(dev_priv, pll_id);
> +	/*
> +	 * ctrl1 register is already shifted for each pll, just use 0 to get
> +	 * the internal shift for each field
> +	 */
> +	state = &pipe_config->dpll_hw_state;
> +	if (state->ctrl1 & DPLL_CTRL1_HDMI_MODE(0)) {
> +		link_clock = skl_calc_wrpll_link(state);
>  	} else {
> -		link_clock = dpll_ctl1 & DPLL_CTRL1_LINK_RATE_MASK(pll_id);
> -		link_clock >>= DPLL_CTRL1_LINK_RATE_SHIFT(pll_id);
> +		link_clock = state->ctrl1 & DPLL_CTRL1_LINK_RATE_MASK(0);
> +		link_clock >>= DPLL_CTRL1_LINK_RATE_SHIFT(0);
>  
>  		switch (link_clock) {
>  		case DPLL_CTRL1_LINK_RATE_810:
> @@ -1587,6 +1581,7 @@ static void skl_ddi_clock_get(struct intel_encoder *encoder,
>  		link_clock *= 2;
>  	}
>  
> +end:
>  	pipe_config->port_clock = link_clock;
>  
>  	ddi_dotclock_get(pipe_config);
> -- 
> 2.20.1

-- 
Ville Syrjälä
Intel