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

[Jani Nikula <jani.nikula@intel.com>]

On Wed, 05 Jun 2024, Ville Syrjälä <ville.syrjala@linux.intel.com> wrote:
> 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?

Whoops.

>
>> +			return 533333;
>
> Why a different default value vs. the other branch?

No idea. :/

>
>> +		}
>>  	}
>> -
>> -	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

-- 
Jani Nikula, Intel