Re: [PATCH 07/12] drm/i915: extend the fsb_freq initialization to more platforms

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Tue, May 28, 2024 at 05:24:56PM +0300, Jani Nikula wrote:
> Initialize fsb frequency for more platforms to be able to use it for GT
> clock and rawclk frequency initialization.
> 
> Note: There's a discrepancy between existing pnv_fsb_freq() and
> i9xx_hrawclk() regarding CLKCFG interpretation. Presume all PNV is
> mobile.
> 
> FIXME: What should the default or failure mode be when the value is
> unknown?
> 
> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
> ---
>  drivers/gpu/drm/i915/soc/intel_dram.c | 54 ++++++++++++++++++++-------
>  1 file changed, 40 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/soc/intel_dram.c b/drivers/gpu/drm/i915/soc/intel_dram.c
> index ace9372244a4..74b5b70e91f9 100644
> --- a/drivers/gpu/drm/i915/soc/intel_dram.c
> +++ b/drivers/gpu/drm/i915/soc/intel_dram.c
> @@ -142,24 +142,50 @@ static void detect_mem_freq(struct drm_i915_private *i915)
>  		drm_dbg(&i915->drm, "DDR speed: %d kHz\n", i915->mem_freq);
>  }
>  
> -static unsigned int pnv_fsb_freq(struct drm_i915_private *i915)
> +static unsigned int i9xx_fsb_freq(struct drm_i915_private *i915)
>  {
>  	u32 fsb;
>  
>  	fsb = intel_uncore_read(&i915->uncore, CLKCFG) & CLKCFG_FSB_MASK;
>  
> -	switch (fsb) {
> -	case CLKCFG_FSB_400:
> -		return 400000;
> -	case CLKCFG_FSB_533:
> -		return 533333;
> -	case CLKCFG_FSB_667:
> -		return 666667;
> -	case CLKCFG_FSB_800:
> -		return 800000;
> +	if (IS_PINEVIEW(i915) || IS_MOBILE(i915)) {
> +		switch (fsb) {
> +		case CLKCFG_FSB_400:
> +			return 400000;
> +		case CLKCFG_FSB_533:
> +			return 533333;
> +		case CLKCFG_FSB_667:
> +			return 666667;
> +		case CLKCFG_FSB_800:
> +			return 800000;
> +		case CLKCFG_FSB_1067:
> +			return 1066667;
> +		case CLKCFG_FSB_1333:
> +			return 1333333;
> +		default:
> +			MISSING_CASE(fsb);
> +			return 1333333;
> +		}
> +	} else {
> +		switch (fsb) {
> +		case CLKCFG_FSB_400_ALT:
> +			return 400000;
> +		case CLKCFG_FSB_533:
> +			return 533333;
> +		case CLKCFG_FSB_667:
> +			return 666667;
> +		case CLKCFG_FSB_800:
> +			return 800000;
> +		case CLKCFG_FSB_1067_ALT:
> +			return 1066667;
> +		case CLKCFG_FSB_1333_ALT:
> +			return 1333333;
> +		case CLKCFG_FSB_1600_ALT:
> +			return 1600000;
> +		default:

No MISSING_CASE() here?

> +			return 533333;

Why a different default value vs. the other branch?

> +		}
>  	}
> -
> -	return 0;
>  }
>  
>  static unsigned int ilk_fsb_freq(struct drm_i915_private *dev_priv)
> @@ -193,8 +219,8 @@ static void detect_fsb_freq(struct drm_i915_private *i915)
>  {
>  	if (GRAPHICS_VER(i915) == 5)
>  		i915->fsb_freq = ilk_fsb_freq(i915);
> -	else if (IS_PINEVIEW(i915))
> -		i915->fsb_freq = pnv_fsb_freq(i915);
> +	else if (GRAPHICS_VER(i915) == 3 || GRAPHICS_VER(i915) == 4)
> +		i915->fsb_freq = i9xx_fsb_freq(i915);
>  
>  	if (i915->fsb_freq)
>  		drm_dbg(&i915->drm, "FSB frequency: %d kHz\n", i915->fsb_freq);
> -- 
> 2.39.2

-- 
Ville Syrjälä
Intel