[Intel-gfx] [PATCH 09/21] drm/i915: Beef up skl_sanitize_cdclk() a bit

[Imre Deak]

On pe, 2016-05-13 at 23:41 +0300, ville.syrjala at linux.intel.com wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> Also verify the DPLL_CTRL1 register value in skl_sanitize_cdclk(), throw
> out a few unneeded variables, and write the CDCLK_CTL check a bit more
> legible way.
> 
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

Reviewed-by: Imre Deak <imre.deak at intel.com>

> ---
>  drivers/gpu/drm/i915/intel_display.c | 18 +++++++++++++-----
>  1 file changed, 13 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 107a7799bdde..493160682b2a 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -5789,9 +5789,7 @@ void skl_init_cdclk(struct drm_i915_private *dev_priv)
>  
>  int skl_sanitize_cdclk(struct drm_i915_private *dev_priv)
>  {
> -	uint32_t lcpll1 = I915_READ(LCPLL1_CTL);
> -	uint32_t cdctl = I915_READ(CDCLK_CTL);
> -	int freq = dev_priv->cdclk_freq;
> +	uint32_t cdctl, expected;
>  
>  	/*
>  	 * check if the pre-os intialized the display
> @@ -5802,7 +5800,14 @@ int skl_sanitize_cdclk(struct drm_i915_private *dev_priv)
>  		goto sanitize;
>  
>  	/* Is PLL enabled and locked ? */
> -	if (!((lcpll1 & LCPLL_PLL_ENABLE) && (lcpll1 & LCPLL_PLL_LOCK)))
> +	if ((I915_READ(LCPLL1_CTL) & (LCPLL_PLL_ENABLE | LCPLL_PLL_LOCK)) !=
> +	    (LCPLL_PLL_ENABLE | LCPLL_PLL_LOCK))
> +		goto sanitize;
> +
> +	if ((I915_READ(DPLL_CTRL1) & (DPLL_CTRL1_HDMI_MODE(SKL_DPLL0) |
> +				      DPLL_CTRL1_SSC(SKL_DPLL0) |
> +				      DPLL_CTRL1_OVERRIDE(SKL_DPLL0))) !=
> +	    DPLL_CTRL1_OVERRIDE(SKL_DPLL0))
>  		goto sanitize;
>  
>  	/* DPLL okay; verify the cdclock
> @@ -5811,7 +5816,10 @@ int skl_sanitize_cdclk(struct drm_i915_private *dev_priv)
>  	 * decimal part is programmed wrong from BIOS where pre-os does not
>  	 * enable display. Verify the same as well.
>  	 */
> -	if (cdctl == ((cdctl & CDCLK_FREQ_SEL_MASK) | skl_cdclk_decimal(freq)))
> +	cdctl = I915_READ(CDCLK_CTL);
> +	expected = (cdctl & CDCLK_FREQ_SEL_MASK) |
> +		skl_cdclk_decimal(dev_priv->cdclk_freq);
> +	if (cdctl == expected)
>  		/* All well; nothing to sanitize */
>  		return false;
>  sanitize: