[Intel-xe] [Intel-gfx] [PATCH v2 23/27] drm/i915/lnl: Start using CDCLK through PLL

[Matt Roper]

On Thu, Sep 07, 2023 at 08:37:53AM -0700, Lucas De Marchi wrote:
> From: Stanislav Lisovskiy <stanislav.lisovskiy at intel.com>
> 
> Introduce correspondent definitions and for choosing between CD2X CDCLK
> and PLL CDCLK as a source. All the entries in cdclk table for xe2lpd are
> defined with PLL CDCLK as source, so simply set it.

There should probably be some mention of removing the cdclk value field
as well since it's technically unrelated to the clock source stuff
described above.

With an extra sentence added,

Reviewed-by: Matt Roper <matthew.d.roper at intel.com>


Matt

> 
> v2:
>   - Remove unneeded comment and use REG_BIT() (Matt Roper)
>   - Rename CDCLK_SOURCE_SEL_CDCLK_PLL() to MDCLK_SOURCE_SEL_CDCLK_PLL
>     to match spec (Lucas)
> 
> Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy at intel.com>
> Signed-off-by: Lucas De Marchi <lucas.demarchi at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_cdclk.c | 9 +++++++--
>  drivers/gpu/drm/i915/i915_reg.h            | 1 +
>  2 files changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.c b/drivers/gpu/drm/i915/display/intel_cdclk.c
> index 7307af2a4af5..abe845906c7c 100644
> --- a/drivers/gpu/drm/i915/display/intel_cdclk.c
> +++ b/drivers/gpu/drm/i915/display/intel_cdclk.c
> @@ -1906,8 +1906,7 @@ static void _bxt_set_cdclk(struct drm_i915_private *dev_priv,
>  		dg2_cdclk_squash_program(dev_priv, waveform);
>  
>  	val = bxt_cdclk_cd2x_div_sel(dev_priv, clock, vco) |
> -		bxt_cdclk_cd2x_pipe(dev_priv, pipe) |
> -		skl_cdclk_decimal(cdclk);
> +		bxt_cdclk_cd2x_pipe(dev_priv, pipe);
>  
>  	/*
>  	 * Disable SSA Precharge when CD clock frequency < 500 MHz,
> @@ -1916,6 +1915,12 @@ static void _bxt_set_cdclk(struct drm_i915_private *dev_priv,
>  	if ((IS_GEMINILAKE(dev_priv) || IS_BROXTON(dev_priv)) &&
>  	    cdclk >= 500000)
>  		val |= BXT_CDCLK_SSA_PRECHARGE_ENABLE;
> +
> +	if (DISPLAY_VER(dev_priv) >= 20)
> +		val |= MDCLK_SOURCE_SEL_CDCLK_PLL;
> +	else
> +		val |= skl_cdclk_decimal(cdclk);
> +
>  	intel_de_write(dev_priv, CDCLK_CTL, val);
>  
>  	if (pipe != INVALID_PIPE)
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index efcf1461988f..c59eb411cf06 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -5884,6 +5884,7 @@ enum skl_power_gate {
>  #define  CDCLK_FREQ_540		REG_FIELD_PREP(CDCLK_FREQ_SEL_MASK, 1)
>  #define  CDCLK_FREQ_337_308		REG_FIELD_PREP(CDCLK_FREQ_SEL_MASK, 2)
>  #define  CDCLK_FREQ_675_617		REG_FIELD_PREP(CDCLK_FREQ_SEL_MASK, 3)
> +#define  MDCLK_SOURCE_SEL_CDCLK_PLL	REG_BIT(25)
>  #define  BXT_CDCLK_CD2X_DIV_SEL_MASK	REG_GENMASK(23, 22)
>  #define  BXT_CDCLK_CD2X_DIV_SEL_1	REG_FIELD_PREP(BXT_CDCLK_CD2X_DIV_SEL_MASK, 0)
>  #define  BXT_CDCLK_CD2X_DIV_SEL_1_5	REG_FIELD_PREP(BXT_CDCLK_CD2X_DIV_SEL_MASK, 1)
> -- 
> 2.40.1
> 

-- 
Matt Roper
Graphics Software Engineer
Linux GPU Platform Enablement
Intel Corporation