Re: [PATCH 1/3] drm/i915/icl: Add new supported CD clocks

Ville Syrjälä
2019-06-19T11:48:52Z

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.
>
> BSpec: 20598
> BSpec: 15729
> Cc: Clint Taylor <Clinton.A.Taylor@intel.com>
> Signed-off-by: José Roberto de Souza <jose.souza@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 };

static?

> + const int *ranges;
> + unsigned int len, i;

just 'int' please

>
> 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);

I'd probably put a break here too for symmetry.

> }
>
> ratio = cdclk / (dev_priv->cdclk.hw.ref / 2);
> --
> 2.22.0
>
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--
Ville Syrjälä
Intel