[Intel-gfx] [PATCH 1/3] drm/i915/icl: Add new supported CD clocks

[Ville Syrjälä]

On Tue, Jun 18, 2019 at 03:50:33PM -0700, José Roberto de Souza wrote:
> Now 180, 172.8 and 192 MHz are supported.
> 
> 180 and 172.8 MHz CD clocks will only be used when audio is not
> enabled as state by BSpec and implemented in
> intel_crtc_compute_min_cdclk(), CD clock must be at least twice of
> Azalia BCLK and BCLK by default is 96 MHz, it could be set to 48 MHz
> but we are not reading it.

Do we know whether this thing still suffers from the glk/cnl issue where
we can't even talk to the codec if cdclk is too low? If it does we need
to adjust the platform check for the "force min cdclk for audio" thing.
Also that is going to suck on icl due to the cd2x divider always being
1 and hence we can't do the optimized cdclk change around audio power
requests.

> 
> BSpec: 20598
> BSpec: 15729
> Cc: Clint Taylor <Clinton.A.Taylor at intel.com>
> Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_cdclk.c | 29 +++++++++++++++-------
>  1 file changed, 20 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.c b/drivers/gpu/drm/i915/display/intel_cdclk.c
> index 8993ab283562..d560e25d3fb5 100644
> --- a/drivers/gpu/drm/i915/display/intel_cdclk.c
> +++ b/drivers/gpu/drm/i915/display/intel_cdclk.c
> @@ -1756,9 +1756,10 @@ static void cnl_sanitize_cdclk(struct drm_i915_private *dev_priv)
>  
>  static int icl_calc_cdclk(int min_cdclk, unsigned int ref)
>  {
> -	int ranges_24[] = { 312000, 552000, 648000 };
> -	int ranges_19_38[] = { 307200, 556800, 652800 };
> -	int *ranges;
> +	const int ranges_24[] = { 180000, 192000, 312000, 552000, 648000 };
> +	const int ranges_19_38[] = { 172800, 192000, 307200, 556800, 652800 };
> +	const int *ranges;
> +	unsigned int len, i;
>  
>  	switch (ref) {
>  	default:
> @@ -1766,19 +1767,22 @@ static int icl_calc_cdclk(int min_cdclk, unsigned int ref)
>  		/* fall through */
>  	case 24000:
>  		ranges = ranges_24;
> +		len = ARRAY_SIZE(ranges_24);
>  		break;
>  	case 19200:
>  	case 38400:
>  		ranges = ranges_19_38;
> +		len = ARRAY_SIZE(ranges_19_38);
>  		break;
>  	}
>  
> -	if (min_cdclk > ranges[1])
> -		return ranges[2];
> -	else if (min_cdclk > ranges[0])
> -		return ranges[1];
> -	else
> -		return ranges[0];
> +	for (i = 0; i < len; i++) {
> +		if (min_cdclk <= ranges[i])
> +			return ranges[i];
> +	}
> +
> +	WARN_ON(min_cdclk > ranges[len - 1]);
> +	return ranges[len - 1];
>  }
>  
>  static int icl_calc_cdclk_pll_vco(struct drm_i915_private *dev_priv, int cdclk)
> @@ -1792,16 +1796,23 @@ static int icl_calc_cdclk_pll_vco(struct drm_i915_private *dev_priv, int cdclk)
>  	default:
>  		MISSING_CASE(cdclk);
>  		/* fall through */
> +	case 172800:
>  	case 307200:
>  	case 556800:
>  	case 652800:
>  		WARN_ON(dev_priv->cdclk.hw.ref != 19200 &&
>  			dev_priv->cdclk.hw.ref != 38400);
>  		break;
> +	case 180000:
>  	case 312000:
>  	case 552000:
>  	case 648000:
>  		WARN_ON(dev_priv->cdclk.hw.ref != 24000);
> +		break;
> +	case 192000:
> +		WARN_ON(dev_priv->cdclk.hw.ref != 19200 &&
> +			dev_priv->cdclk.hw.ref != 38400 &&
> +			dev_priv->cdclk.hw.ref != 24000);
>  	}
>  
>  	ratio = cdclk / (dev_priv->cdclk.hw.ref / 2);
> -- 
> 2.22.0
> 
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-- 
Ville Syrjälä
Intel