Hi, Lucas.
On Thu, Sep 08, 2022 at 01:08:15PM -0700, Lucas De Marchi wrote:
> Instead of calling read_clock_frequency() to walk the if/else ladder
> per platform, move the ladder to intel_gt_init_clock_frequency() and
> use one function per branch.
I think the split of current code into separate functions looks good. However,
maybe the correct place to do that would be inside read_clock_frequency()
instead of intel_gt_init_clock_frequency(), since read_clock_frequency() is used
inside intel_gt_check_clock_frequency().
>
> With the new logic, it's now clear the call to
> gen9_get_crystal_clock_freq() was just dead code, as gen9 is handled by
> another function and there is no version 10. Remove that function and
> the caller.
>
> Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> Signed-off-by: Lucas De Marchi <lucas.demarchi@xxxxxxxxx>
>
> 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 93608c9349fd..ebddbf7542bc 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gt_clock_utils.c
> +++ b/drivers/gpu/drm/i915/gt/intel_gt_clock_utils.c
> @@ -26,26 +26,6 @@ static u32 read_reference_ts_freq(struct intel_uncore *uncore)
> return base_freq + frac_freq;
> }
>
> -static u32 gen9_get_crystal_clock_freq(struct intel_uncore *uncore,
> - u32 rpm_config_reg)
> -{
> - u32 f19_2_mhz = 19200000;
> - u32 f24_mhz = 24000000;
> - u32 crystal_clock =
> - (rpm_config_reg & GEN9_RPM_CONFIG0_CRYSTAL_CLOCK_FREQ_MASK) >>
> - GEN9_RPM_CONFIG0_CRYSTAL_CLOCK_FREQ_SHIFT;
> -
> - switch (crystal_clock) {
> - case GEN9_RPM_CONFIG0_CRYSTAL_CLOCK_FREQ_19_2_MHZ:
> - return f19_2_mhz;
> - case GEN9_RPM_CONFIG0_CRYSTAL_CLOCK_FREQ_24_MHZ:
> - return f24_mhz;
> - default:
> - MISSING_CASE(crystal_clock);
> - return 0;
> - }
> -}
> -
> static u32 gen11_get_crystal_clock_freq(struct intel_uncore *uncore,
> u32 rpm_config_reg)
> {
> @@ -72,95 +52,101 @@ static u32 gen11_get_crystal_clock_freq(struct intel_uncore *uncore,
> }
> }
>
> -static u32 read_clock_frequency(struct intel_uncore *uncore)
> +static u32 gen11_read_clock_frequency(struct intel_uncore *uncore)
> {
> - u32 f12_5_mhz = 12500000;
> - u32 f19_2_mhz = 19200000;
> - u32 f24_mhz = 24000000;
> + u32 ctc_reg = intel_uncore_read(uncore, CTC_MODE);
> + u32 freq = 0;
>
> - if (GRAPHICS_VER(uncore->i915) >= 11) {
> - u32 ctc_reg = intel_uncore_read(uncore, CTC_MODE);
> - u32 freq = 0;
> + /*
> + * Note that on gen11+, the clock frequency may be reconfigured.
> + * We do not, and we assume nobody else does.
> + *
> + * 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);
> +
> + freq = gen11_get_crystal_clock_freq(uncore, c0);
>
> /*
> - * 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);
> -
> - /*
> - * 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);
> - }
> -
> - return freq;
> - } else if (GRAPHICS_VER(uncore->i915) >= 9) {
> - u32 ctc_reg = intel_uncore_read(uncore, CTC_MODE);
> - u32 freq = 0;
> -
> - 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;
> -
> - /*
> - * 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);
> - }
> -
> - 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).
> + * Now figure out how the command stream's timestamp
> + * register increments from this frequency (it might
> + * increment only every few clock cycle).
> */
> - return f12_5_mhz;
> + freq >>= 3 - ((c0 & GEN10_RPM_CONFIG0_CTC_SHIFT_PARAMETER_MASK) >>
> + GEN10_RPM_CONFIG0_CTC_SHIFT_PARAMETER_SHIFT);
> + }
> +
> + return freq;
> +}
> +
> +static u32 gen9_read_clock_frequency(struct intel_uncore *uncore)
> +{
> + u32 ctc_reg = intel_uncore_read(uncore, CTC_MODE);
> + u32 freq = 0;
> +
> + if ((ctc_reg & CTC_SOURCE_PARAMETER_MASK) == CTC_SOURCE_DIVIDE_LOGIC) {
> + freq = read_reference_ts_freq(uncore);
> } else {
> + freq = IS_GEN9_LP(uncore->i915) ? 19200000 : 24000000;
> +
> /*
> - * PRMs say:
> - *
> - * "The value in this register increments once every 16
> - * hclks." (through the “Clocking Configuration”
> - * (“CLKCFG”) MCHBAR register)
> + * Now figure out how the command stream's timestamp
> + * register increments from this frequency (it might
> + * increment only every few clock cycle).
> */
> - return RUNTIME_INFO(uncore->i915)->rawclk_freq * 1000 / 16;
> + freq >>= 3 - ((ctc_reg & CTC_SHIFT_PARAMETER_MASK) >>
> + CTC_SHIFT_PARAMETER_SHIFT);
> }
> +
> + return freq;
> }
>
> -void intel_gt_init_clock_frequency(struct intel_gt *gt)
> +static u32 gen5_read_clock_frequency(struct intel_uncore *uncore)
> {
> /*
> - * Note that on gen11+, the clock frequency may be reconfigured.
> - * We do not, and we assume nobody else does.
> + * 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).
> */
> - gt->clock_frequency = read_clock_frequency(gt->uncore);
> - if (gt->clock_frequency)
> - gt->clock_period_ns = intel_gt_clock_interval_to_ns(gt, 1);
> + return 12500000;
> +}
> +
> +static u32 read_clock_frequency(struct intel_uncore *uncore)
> +{
> + /*
> + * 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;
> +}
> +
> +void intel_gt_init_clock_frequency(struct intel_gt *gt)
> +{
> + if (GRAPHICS_VER(gt->i915) >= 11)
> + gt->clock_frequency = gen11_read_clock_frequency(gt->uncore);
> + else if (GRAPHICS_VER(gt->i915) >= 9)
> + gt->clock_frequency = gen9_read_clock_frequency(gt->uncore);
> + else if (GRAPHICS_VER(gt->i915) >= 5)
> + gt->clock_frequency = gen5_read_clock_frequency(gt->uncore);
> + else
> + gt->clock_frequency = read_clock_frequency(gt->uncore);
>
> /* Icelake appears to use another fixed frequency for CTX_TIMESTAMP */
> if (GRAPHICS_VER(gt->i915) == 11)
> gt->clock_period_ns = NSEC_PER_SEC / 13750000;
> + else if (gt->clock_frequency)
> + gt->clock_period_ns = intel_gt_clock_interval_to_ns(gt, 1);
>
> GT_TRACE(gt,
> "Using clock frequency: %dkHz, period: %dns, wrap: %lldms\n",
>
> --
> b4 0.10.0-dev-df873
