[PATCH v7 1/3] thermal: ACPI: Add ACPI trip point routines

Rafael J. Wysocki
2023-01-23T18:41:56Z

From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Add library routines to populate a generic thermal trip point
structure with data obtained by evaluating a specific object in the
ACPI Namespace.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Co-developed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
drivers/thermal/Kconfig | 4 +
drivers/thermal/Makefile | 1
drivers/thermal/thermal_acpi.c | 150 +++++++++++++++++++++++++++++++++++++++++
include/linux/thermal.h | 8 ++
4 files changed, 163 insertions(+)
create mode 100644 drivers/thermal/thermal_acpi.c

Index: linux-pm/drivers/thermal/Kconfig
===================================================================
--- linux-pm.orig/drivers/thermal/Kconfig
+++ linux-pm/drivers/thermal/Kconfig
@@ -76,6 +76,10 @@ config THERMAL_OF
Say 'Y' here if you need to build thermal infrastructure
based on device tree.

+config THERMAL_ACPI
+ depends on ACPI
+ bool
+
config THERMAL_WRITABLE_TRIPS
bool "Enable writable trip points"
help
Index: linux-pm/drivers/thermal/Makefile
===================================================================
--- linux-pm.orig/drivers/thermal/Makefile
+++ linux-pm/drivers/thermal/Makefile
@@ -13,6 +13,7 @@ thermal_sys-$(CONFIG_THERMAL_NETLINK) +
# interface to/from other layers providing sensors
thermal_sys-$(CONFIG_THERMAL_HWMON) += thermal_hwmon.o
thermal_sys-$(CONFIG_THERMAL_OF) += thermal_of.o
+thermal_sys-$(CONFIG_THERMAL_ACPI) += thermal_acpi.o

# governors
thermal_sys-$(CONFIG_THERMAL_GOV_FAIR_SHARE) += gov_fair_share.o
Index: linux-pm/drivers/thermal/thermal_acpi.c
===================================================================
--- /dev/null
+++ linux-pm/drivers/thermal/thermal_acpi.c
@@ -0,0 +1,150 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2023 Linaro Limited
+ * Copyright 2023 Intel Corporation
+ *
+ * Library routines for populating a generic thermal trip point structure
+ * with data obtained by evaluating a specific object in the ACPI Namespace.
+ */
+#include <linux/acpi.h>
+#include <linux/units.h>
+
+#include "thermal_core.h"
+
+/*
+ * Minimum temperature for full military grade is 218°K (-55°C) and
+ * max temperature is 448°K (175°C). We can consider those values as
+ * the boundaries for the [trips] temperature returned by the
+ * firmware. Any values out of these boundaries may be considered
+ * bogus and we can assume the firmware has no data to provide.
+ */
+#define TEMP_MIN_DECIK 2180
+#define TEMP_MAX_DECIK 4480
+
+static int thermal_acpi_trip_init(struct acpi_device *adev,
+ enum thermal_trip_type type, int id,
+ struct thermal_trip *trip)
+{
+ unsigned long long temp;
+ acpi_status status;
+ char obj_name[5];
+
+ switch (type) {
+ case THERMAL_TRIP_ACTIVE:
+ if (id < 0 || id > 9)
+ return -EINVAL;
+
+ obj_name[1] = 'A';
+ obj_name[2] = 'C';
+ obj_name[3] = '0' + id;
+ break;
+ case THERMAL_TRIP_PASSIVE:
+ obj_name[1] = 'P';
+ obj_name[2] = 'S';
+ obj_name[3] = 'V';
+ break;
+ case THERMAL_TRIP_HOT:
+ obj_name[1] = 'H';
+ obj_name[2] = 'O';
+ obj_name[3] = 'T';
+ break;
+ case THERMAL_TRIP_CRITICAL:
+ obj_name[1] = 'C';
+ obj_name[2] = 'R';
+ obj_name[3] = 'T';
+ break;
+ }
+
+ obj_name[0] = '_';
+ obj_name[4] = '\0';
+
+ status = acpi_evaluate_integer(adev->handle, obj_name, NULL, &temp);
+ if (ACPI_FAILURE(status)) {
+ acpi_handle_debug(adev->handle, "%s evaluation failed\n", obj_name);
+ return -ENODATA;
+ }
+
+ if (temp < TEMP_MIN_DECIK || temp >= TEMP_MAX_DECIK) {
+ acpi_handle_debug(adev->handle, "%s result %llu out of range\n",
+ obj_name, temp);
+ return -ENODATA;
+ }
+
+ trip->temperature = deci_kelvin_to_millicelsius(temp);
+ trip->hysteresis = 0;
+ trip->type = type;
+
+ return 0;
+}
+
+/**
+ * thermal_acpi_trip_active - Get the specified active trip point
+ * @adev: Thermal zone ACPI device object to get the description from.
+ * @id: Active cooling level (0 - 9).
+ * @trip: Trip point structure to be populated on success.
+ *
+ * Evaluate the _ACx object for the thermal zone represented by @adev to obtain
+ * the temperature of the active cooling trip point corresponding to the active
+ * cooling level given by @id and initialize @trip as an active trip point using
+ * that temperature value.
+ *
+ * Return 0 on success or a negative error value on failure.
+ */
+int thermal_acpi_trip_active(struct acpi_device *adev, int id,
+ struct thermal_trip *trip)
+{
+ return thermal_acpi_trip_init(adev, THERMAL_TRIP_ACTIVE, id, trip);
+}
+EXPORT_SYMBOL_GPL(thermal_acpi_trip_active);
+
+/**
+ * thermal_acpi_trip_passive - Get the passive trip point
+ * @adev: Thermal zone ACPI device object to get the description from.
+ * @trip: Trip point structure to be populated on success.
+ *
+ * Evaluate the _PSV object for the thermal zone represented by @adev to obtain
+ * the temperature of the passive cooling trip point and initialize @trip as a
+ * passive trip point using that temperature value.
+ *
+ * Return 0 on success or -ENODATA on failure.
+ */
+int thermal_acpi_trip_passive(struct acpi_device *adev, struct thermal_trip *trip)
+{
+ return thermal_acpi_trip_init(adev, THERMAL_TRIP_PASSIVE, INT_MAX, trip);
+}
+EXPORT_SYMBOL_GPL(thermal_acpi_trip_passive);
+
+/**
+ * thermal_acpi_trip_hot - Get the near critical trip point
+ * @adev: the ACPI device to get the description from.
+ * @trip: a &struct thermal_trip to be filled if the function succeed.
+ *
+ * Evaluate the _HOT object for the thermal zone represented by @adev to obtain
+ * the temperature of the trip point at which the system is expected to be put
+ * into the S4 sleep state and initialize @trip as a hot trip point using that
+ * temperature value.
+ *
+ * Return 0 on success or -ENODATA on failure.
+ */
+int thermal_acpi_trip_hot(struct acpi_device *adev, struct thermal_trip *trip)
+{
+ return thermal_acpi_trip_init(adev, THERMAL_TRIP_HOT, INT_MAX, trip);
+}
+EXPORT_SYMBOL_GPL(thermal_acpi_trip_hot);
+
+/**
+ * thermal_acpi_trip_critical - Get the critical trip point
+ * @adev: the ACPI device to get the description from.
+ * @trip: a &struct thermal_trip to be filled if the function succeed.
+ *
+ * Evaluate the _CRT object for the thermal zone represented by @adev to obtain
+ * the temperature of the critical cooling trip point and initialize @trip as a
+ * critical trip point using that temperature value.
+ *
+ * Return 0 on success or -ENODATA on failure.
+ */
+int thermal_acpi_trip_critical(struct acpi_device *adev, struct thermal_trip *trip)
+{
+ return thermal_acpi_trip_init(adev, THERMAL_TRIP_CRITICAL, INT_MAX, trip);
+}
+EXPORT_SYMBOL_GPL(thermal_acpi_trip_critical);
Index: linux-pm/include/linux/thermal.h
===================================================================
--- linux-pm.orig/include/linux/thermal.h
+++ linux-pm/include/linux/thermal.h
@@ -346,6 +346,14 @@ int thermal_zone_get_num_trips(struct th

int thermal_zone_get_crit_temp(struct thermal_zone_device *tz, int *temp);

+#ifdef CONFIG_THERMAL_ACPI
+int thermal_acpi_trip_active(struct acpi_device *adev, int id,
+ struct thermal_trip *trip);
+int thermal_acpi_trip_passive(struct acpi_device *adev, struct thermal_trip *trip);
+int thermal_acpi_trip_hot(struct acpi_device *adev, struct thermal_trip *trip);
+int thermal_acpi_trip_critical(struct acpi_device *adev, struct thermal_trip *trip);
+#endif
+
#ifdef CONFIG_THERMAL
struct thermal_zone_device *thermal_zone_device_register(const char *, int, int,
void *, struct thermal_zone_device_ops *,