diff mbox series

[v1,2/3] drm/i915/gt: Extract per-platform function for frequency read

Message ID 20220908-if-ladder-v1-2-9949a713ca08@intel.com (mailing list archive)
State New, archived
Headers show
Series drm/i915: A couple of if/else ladder refactors | expand

Commit Message

Lucas De Marchi Sept. 8, 2022, 8:08 p.m. UTC 
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.

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@linux.intel.com>
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>

Comments

Gustavo Sousa Sept. 13, 2022, 11:17 a.m. UTC | #1 
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@linux.intel.com>
> Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
> 
> 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
Lucas De Marchi Sept. 13, 2022, 3:36 p.m. UTC | #2 
On Tue, Sep 13, 2022 at 08:17:02AM -0300, Gustavo Sousa wrote:
>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().

indeed, good catch. I forgot about the debug thing reading it again
later.

thanks
Lucas De Marchi
diff mbox series

Patch

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",