Change in ...coreboot[master]: soc/intel/common/block/acpi: fix P-States extra entry

[Patrick Georgi (Code Review)]

Patrick Georgi has submitted this change and it was merged. ( https://review.coreboot.org/c/coreboot/+/25429 )

Change subject: soc/intel/common/block/acpi: fix P-States extra entry
......................................................................

soc/intel/common/block/acpi: fix P-States extra entry

The ratio_max step is appearing twice when (ratio_max - ratio_min)
is evenly divisible by the ratio step.

This is because in this case there are no rounding down of ratio_max in
the for loop.

Thanks Jay Talbott for the step calculation algorithm.

Change-Id: I91090b4d87eb82b57055c24271d679d1cbb3b7a7
Signed-off-by: Julien Viard de Galbert 
Reviewed-on: https://review.coreboot.org/c/25429
Tested-by: build bot (Jenkins) 
Reviewed-by: Patrick Georgi 
---
M src/soc/intel/common/block/acpi/acpi.c
1 file changed, 16 insertions(+), 10 deletions(-)

Approvals:
  build bot (Jenkins): Verified
  Patrick Georgi: Looks good to me, approved

diff --git a/src/soc/intel/common/block/acpi/acpi.c b/src/soc/intel/common/block/acpi/acpi.c
index 0ea6cb9..21d877b 100644
--- a/src/soc/intel/common/block/acpi/acpi.c
+++ b/src/soc/intel/common/block/acpi/acpi.c
@@ -299,11 +299,13 @@
    int ratio_min, ratio_max, ratio_turbo, ratio_step;
    int coord_type, power_max, num_entries;
    int ratio, power, clock, clock_max;
+	bool turbo;

coord_type = cpu_get_coord_type();
    ratio_min = cpu_get_min_ratio();
    ratio_max = cpu_get_max_ratio();
    clock_max = (ratio_max * cpu_get_bus_clock()) / KHz;
+	turbo = (get_turbo_state() == TURBO_ENABLED);

/* Calculate CPU TDP in mW */
    power_max = cpu_get_power_max();
@@ -321,16 +323,21 @@

/* Determine ratio points */
    ratio_step = PSS_RATIO_STEP;
-	num_entries = ((ratio_max - ratio_min) / ratio_step) + 1;
-	if (num_entries > PSS_MAX_ENTRIES) {
-		ratio_step += 1;
+	do {
    	num_entries = ((ratio_max - ratio_min) / ratio_step) + 1;
-	}
+		if (((ratio_max - ratio_min) % ratio_step) > 0)
+			num_entries += 1;
+		if (turbo)
+			num_entries += 1;
+		if (num_entries > PSS_MAX_ENTRIES)
+			ratio_step += 1;
+	} while (num_entries > PSS_MAX_ENTRIES);
+
+	/* _PSS package count depends on Turbo */
+	acpigen_write_package(num_entries);

/* P[T] is Turbo state if enabled */
-	if (get_turbo_state() == TURBO_ENABLED) {
-		/* _PSS package count including Turbo */
-		acpigen_write_package(num_entries + 2);
+	if (turbo) {
    	ratio_turbo = cpu_get_max_turbo_ratio();

/* Add entry for Turbo ratio */
@@ -340,9 +347,7 @@
    				  PSS_LATENCY_BUSMASTER,/* lat2 */
    				  ratio_turbo << 8,	/* control */
    				  ratio_turbo << 8);	/* status */
-	} else {
-		/* _PSS package count without Turbo */
-		acpigen_write_package(num_entries + 1);
+		num_entries -= 1;
    }

/* First regular entry is max non-turbo ratio */
@@ -352,6 +357,7 @@
    			  PSS_LATENCY_BUSMASTER,/* lat2 */
    			  ratio_max << 8,	/* control */
    			  ratio_max << 8);	/* status */
+	num_entries -= 1;

/* Generate the remaining entries */
    for (ratio = ratio_min + ((num_entries - 1) * ratio_step);