On Wed, Sep 07, 2022 at 01:30:41PM -0700, Lucas De Marchi wrote:
> Continue converting the driver to the convention of last version first,
> extending it to the future platforms. Now, any GRAPHICS_VER >= 11 will
> be handled by the first branch.
> 
> With the new ranges it's easier to see what platform a branch started to
> be taken. Besides the >= 11 change, the branch taken for GRAPHICS_VER == 10
> is also different, but currently there is no such platform in i915.
> 
> Cc: Matt Roper <matthew.d.ro...@intel.com>
> Signed-off-by: Lucas De Marchi <lucas.demar...@intel.com>
> ---
>  .../gpu/drm/i915/gt/intel_gt_clock_utils.c    | 77 +++++++++----------
>  1 file changed, 37 insertions(+), 40 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gt/intel_gt_clock_utils.c 
> b/drivers/gpu/drm/i915/gt/intel_gt_clock_utils.c
> index d5d1b04dbcad..93608c9349fd 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gt_clock_utils.c
> +++ b/drivers/gpu/drm/i915/gt/intel_gt_clock_utils.c
> @@ -78,77 +78,74 @@ static u32 read_clock_frequency(struct intel_uncore 
> *uncore)
>       u32 f19_2_mhz = 19200000;
>       u32 f24_mhz = 24000000;
>  
> -     if (GRAPHICS_VER(uncore->i915) <= 4) {
> -             /*
> -              * PRMs say:
> -              *
> -              *     "The value in this register increments once every 16
> -              *      hclks." (through the “Clocking Configuration”
> -              *      (“CLKCFG”) MCHBAR register)
> -              */
> -             return RUNTIME_INFO(uncore->i915)->rawclk_freq * 1000 / 16;
> -     } else if (GRAPHICS_VER(uncore->i915) <= 8) {
> -             /*
> -              * PRMs say:
> -              *
> -              *     "The PCU TSC counts 10ns increments; this timestamp
> -              *      reflects bits 38:3 of the TSC (i.e. 80ns granularity,
> -              *      rolling over every 1.5 hours).
> -              */
> -             return f12_5_mhz;
> -     } else if (GRAPHICS_VER(uncore->i915) <= 9) {

Is there a good reason each of these branches isn't just its own function?

> +     if (GRAPHICS_VER(uncore->i915) >= 11) {
>               u32 ctc_reg = intel_uncore_read(uncore, CTC_MODE);
>               u32 freq = 0;
>  
> +             /*
> +              * First figure out the reference frequency. There are 2 ways
> +              * we can compute the frequency, either through the
> +              * TIMESTAMP_OVERRIDE register or through RPM_CONFIG. CTC_MODE
> +              * tells us which one we should use.
> +              */
>               if ((ctc_reg & CTC_SOURCE_PARAMETER_MASK) == 
> CTC_SOURCE_DIVIDE_LOGIC) {
>                       freq = read_reference_ts_freq(uncore);
>               } else {
> -                     freq = IS_GEN9_LP(uncore->i915) ? f19_2_mhz : f24_mhz;
> +                     u32 c0 = intel_uncore_read(uncore, RPM_CONFIG0);
> +
> +                     if (GRAPHICS_VER(uncore->i915) >= 11)
> +                             freq = gen11_get_crystal_clock_freq(uncore, c0);
> +                     else
> +                             freq = gen9_get_crystal_clock_freq(uncore, c0);
>  
>                       /*
>                        * Now figure out how the command stream's timestamp
>                        * register increments from this frequency (it might
>                        * increment only every few clock cycle).
>                        */
> -                     freq >>= 3 - ((ctc_reg & CTC_SHIFT_PARAMETER_MASK) >>
> -                                   CTC_SHIFT_PARAMETER_SHIFT);
> +                     freq >>= 3 - ((c0 & 
> GEN10_RPM_CONFIG0_CTC_SHIFT_PARAMETER_MASK) >>
> +                                   
> GEN10_RPM_CONFIG0_CTC_SHIFT_PARAMETER_SHIFT);
>               }
>  
>               return freq;
> -     } else if (GRAPHICS_VER(uncore->i915) <= 12) {
> +     } else if (GRAPHICS_VER(uncore->i915) >= 9) {
>               u32 ctc_reg = intel_uncore_read(uncore, CTC_MODE);
>               u32 freq = 0;
>  
> -             /*
> -              * First figure out the reference frequency. There are 2 ways
> -              * we can compute the frequency, either through the
> -              * TIMESTAMP_OVERRIDE register or through RPM_CONFIG. CTC_MODE
> -              * tells us which one we should use.
> -              */
>               if ((ctc_reg & CTC_SOURCE_PARAMETER_MASK) == 
> CTC_SOURCE_DIVIDE_LOGIC) {
>                       freq = read_reference_ts_freq(uncore);
>               } else {
> -                     u32 c0 = intel_uncore_read(uncore, RPM_CONFIG0);
> -
> -                     if (GRAPHICS_VER(uncore->i915) >= 11)
> -                             freq = gen11_get_crystal_clock_freq(uncore, c0);
> -                     else
> -                             freq = gen9_get_crystal_clock_freq(uncore, c0);
> +                     freq = IS_GEN9_LP(uncore->i915) ? f19_2_mhz : f24_mhz;
>  
>                       /*
>                        * Now figure out how the command stream's timestamp
>                        * register increments from this frequency (it might
>                        * increment only every few clock cycle).
>                        */
> -                     freq >>= 3 - ((c0 & 
> GEN10_RPM_CONFIG0_CTC_SHIFT_PARAMETER_MASK) >>
> -                                   
> GEN10_RPM_CONFIG0_CTC_SHIFT_PARAMETER_SHIFT);
> +                     freq >>= 3 - ((ctc_reg & CTC_SHIFT_PARAMETER_MASK) >>
> +                                   CTC_SHIFT_PARAMETER_SHIFT);
>               }
>  
>               return freq;
> +     } else if (GRAPHICS_VER(uncore->i915) >= 5) {
> +             /*
> +              * PRMs say:
> +              *
> +              *     "The PCU TSC counts 10ns increments; this timestamp
> +              *      reflects bits 38:3 of the TSC (i.e. 80ns granularity,
> +              *      rolling over every 1.5 hours).
> +              */
> +             return f12_5_mhz;
> +     } else {
> +             /*
> +              * PRMs say:
> +              *
> +              *     "The value in this register increments once every 16
> +              *      hclks." (through the “Clocking Configuration”
> +              *      (“CLKCFG”) MCHBAR register)
> +              */
> +             return RUNTIME_INFO(uncore->i915)->rawclk_freq * 1000 / 16;
>       }
> -
> -     MISSING_CASE("Unknown gen, unable to read command streamer timestamp 
> frequency\n");
> -     return 0;
>  }
>  
>  void intel_gt_init_clock_frequency(struct intel_gt *gt)
> -- 
> 2.37.2

-- 
Ville Syrjälä
Intel

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