dptf: Add support for Passive Policies
This patch adds support for emitting the Thermal Relationship Table, as
well as _PSV Methods, which together form the basis for DPTF Passive
Policies.
BUG=b:143539650
TEST=compiles
Change-Id: I82e1c9022999b0a2a733aa6cd9c98a850e6f5408
Signed-off-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/41886
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>
diff --git a/src/acpi/acpigen_dptf.c b/src/acpi/acpigen_dptf.c
index 74e9191..abd99c1 100644
--- a/src/acpi/acpigen_dptf.c
+++ b/src/acpi/acpigen_dptf.c
@@ -9,6 +9,7 @@
/* Defaults */
enum {
ART_REVISION = 0,
+ DEFAULT_PRIORITY = 100,
DEFAULT_WEIGHT = 100,
DPTF_MAX_ART_THRESHOLDS = 10,
};
@@ -19,6 +20,12 @@
return deg_c * 10 + 2732;
}
+/* Converts ms to 1/10th second for ACPI */
+static int to_acpi_time(int ms)
+{
+ return ms / 100;
+}
+
/* Writes out a 0-argument non-Serialized Method that returns an Integer */
static void write_simple_return_method(const char *name, int value)
{
@@ -27,6 +34,13 @@
acpigen_pop_len(); /* Method */
}
+/* Writes out 'count' ZEROs in a row */
+static void write_zeros(int count)
+{
+ for (; count; --count)
+ acpigen_write_integer(0);
+}
+
/* Return the assigned namestring of any participant */
static const char *namestring_of(enum dptf_participant participant)
{
@@ -164,3 +178,87 @@
write_active_relationship_table(policies, max_count);
write_active_cooling_methods(policies, max_count);
}
+
+/*
+ * This writes out the Thermal Relationship Table, which describes the thermal relationships
+ * between participants in a thermal zone. This information is used to passively cool (i.e.,
+ * throttle) the Source (source of heat), in order to indirectly cool the Target (temperature
+ * sensor).
+ */
+static void write_thermal_relationship_table(const struct dptf_passive_policy *policies,
+ int max_count)
+{
+ char *pkg_count;
+ int i;
+
+ /* Nothing to do */
+ if (!max_count || policies[0].source == DPTF_NONE)
+ return;
+
+ acpigen_write_scope(TOPLEVEL_DPTF_SCOPE);
+
+ /*
+ * A _TRT Revision (TRTR) of 1 means that the 'Priority' field is an arbitrary priority
+ * value to be used for this specific relationship. The priority value determines the
+ * order in which various sources are used in a passive thermal action for a given
+ * target.
+ */
+ acpigen_write_name_integer("TRTR", 1);
+
+ /* Thermal Relationship Table */
+ acpigen_write_method("_TRT", 0);
+
+ /* Return this package */
+ acpigen_emit_byte(RETURN_OP);
+ pkg_count = acpigen_write_package(0);
+
+ for (i = 0; i < max_count; ++i) {
+ /* Stop writing the table once an entry is empty */
+ if (policies[i].source == DPTF_NONE)
+ break;
+
+ /* Keep track of outer package item count */
+ (*pkg_count)++;
+
+ acpigen_write_package(8);
+
+ /* Source, Target, Priority, Sampling Period */
+ acpigen_emit_namestring(namestring_of(policies[i].source));
+ acpigen_emit_namestring(namestring_of(policies[i].target));
+ acpigen_write_integer(DEFAULT_IF_0(policies[i].priority, DEFAULT_PRIORITY));
+ acpigen_write_integer(to_acpi_time(policies[i].period));
+
+ /* Reserved */
+ write_zeros(4);
+
+ acpigen_pop_len(); /* Package */
+ }
+
+ acpigen_pop_len(); /* Package */
+ acpigen_pop_len(); /* Method */
+ acpigen_pop_len(); /* Scope */
+}
+
+/*
+ * When a temperature sensor measures above its the temperature returned in its _PSV Method,
+ * DPTF will begin throttling Sources in order to indirectly cool the sensor.
+ */
+static void write_all_PSV(const struct dptf_passive_policy *policies, int max_count)
+{
+ int i;
+
+ for (i = 0; i < max_count; ++i) {
+ if (policies[i].source == DPTF_NONE)
+ break;
+
+ dptf_write_scope(policies[i].target);
+ write_simple_return_method("_PSV", to_acpi_temp(policies[i].temp));
+ acpigen_pop_len(); /* Scope */
+ }
+}
+
+void dptf_write_passive_policies(const struct dptf_passive_policy *policies, int max_count)
+{
+ write_thermal_relationship_table(policies, max_count);
+ write_all_PSV(policies, max_count);
+}
diff --git a/src/drivers/intel/dptf/chip.h b/src/drivers/intel/dptf/chip.h
index 730d23e..0cd2ad2 100644
--- a/src/drivers/intel/dptf/chip.h
+++ b/src/drivers/intel/dptf/chip.h
@@ -8,6 +8,7 @@
struct drivers_intel_dptf_config {
struct {
struct dptf_active_policy active[DPTF_MAX_ACTIVE_POLICIES];
+ struct dptf_passive_policy passive[DPTF_MAX_PASSIVE_POLICIES];
} policies;
};
diff --git a/src/drivers/intel/dptf/dptf.c b/src/drivers/intel/dptf/dptf.c
index 20f8d9b..74f4812 100644
--- a/src/drivers/intel/dptf/dptf.c
+++ b/src/drivers/intel/dptf/dptf.c
@@ -35,6 +35,12 @@
if (config->policies.active[i].target == participant)
return true;
+ /* Passive? */
+ for (i = 0; i < DPTF_MAX_PASSIVE_POLICIES; ++i)
+ if (config->policies.passive[i].source == participant ||
+ config->policies.passive[i].target == participant)
+ return true;
+
/* Check fan as well (its use is implicit in the Active policy) */
if (participant == DPTF_FAN && config->policies.active[0].target != DPTF_NONE)
return true;
@@ -55,6 +61,9 @@
dptf_write_active_policies(config->policies.active,
DPTF_MAX_ACTIVE_POLICIES);
+ dptf_write_passive_policies(config->policies.passive,
+ DPTF_MAX_PASSIVE_POLICIES);
+
printk(BIOS_INFO, "\\_SB.DPTF: %s at %s\n", dev->chip_ops->name, dev_path(dev));
}
diff --git a/src/include/acpi/acpigen_dptf.h b/src/include/acpi/acpigen_dptf.h
index a082b62..214578a 100644
--- a/src/include/acpi/acpigen_dptf.h
+++ b/src/include/acpi/acpigen_dptf.h
@@ -27,6 +27,7 @@
/* A device can only define _AC0 .. _AC9 i.e. between 0 and 10 Active Cooling Methods */
DPTF_MAX_ACX = 10,
DPTF_MAX_ACTIVE_POLICIES = (DPTF_PARTICIPANT_COUNT-1),
+ DPTF_MAX_PASSIVE_POLICIES = (DPTF_PARTICIPANT_COUNT-1),
};
/* Active Policy */
@@ -44,6 +45,20 @@
} thresholds[DPTF_MAX_ACX];
};
+/* Passive Policy */
+struct dptf_passive_policy {
+ /* The device that can be throttled */
+ enum dptf_participant source;
+ /* The device that controls the throttling */
+ enum dptf_participant target;
+ /* How often to check the temperature for required throttling (ms) */
+ uint16_t period;
+ /* The trip point for turning on throttling (degrees C) */
+ uint8_t temp;
+ /* Relative priority between Policies */
+ uint8_t priority;
+};
+
/*
* This function provides tables of temperature and corresponding fan or percent. When the
* temperature thresholds are met (_AC0 - _AC9), the fan is driven to corresponding percentage
@@ -51,6 +66,14 @@
*/
void dptf_write_active_policies(const struct dptf_active_policy *policies, int max_count);
+/*
+ * This function uses the definition of the passive policies to write out _PSV Methods on all
+ * participants that define it. It also writes out the Thermal Relationship Table
+ * (\_SB.DPTF._TRT), which describes various passive (i.e., throttling) policies that can be
+ * applies when temperature sensors reach the _PSV threshold.
+ */
+void dptf_write_passive_policies(const struct dptf_passive_policy *policies, int max_count);
+
/* Helper method to open the scope for a given participant. */
void dptf_write_scope(enum dptf_participant participant);