thermal_zone.c

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/* SPDX-License-Identifier: GPL-2.0-only */
 
#include <acpi/acpigen.h>
#include <assert.h>
#include <commonlib/bsd/helpers.h>
#include <console/console.h>
#include <device/device.h>
#include <stdlib.h>
#include <string.h>
 
#include "chip.h"
 
#define TZ_DEVICE_PATH  "\\_TZ"
/* These defaults should be good enough for most systems */
#define DEFAULT_TC1     2
#define DEFAULT_TC2     5
#define DEFAULT_TSP     10
 
#define CELSIUS_TO_DECI_KELVIN(temp_c)  ((temp_c) * 10 + 2731)
#define SECONDS_TO_DECI_SECONDS(s)      ((s) * 10)
 
static const char *thermal_zone_acpi_name(const struct device *dev)
{
        char *name;
 
        if (dev->path.type != DEVICE_PATH_GENERIC)
                return NULL;
 
        name = malloc(ACPI_NAME_BUFFER_SIZE);
        snprintf(name, ACPI_NAME_BUFFER_SIZE, "TM%02X", dev->path.generic.id);
 
        return name;
}
 
static void thermal_zone_fill_ssdt(const struct device *dev)
{
        struct drivers_acpi_thermal_zone_config *config = config_of(dev);
        const char *scope;
        const char *name;
 
        assert(dev->path.type == DEVICE_PATH_GENERIC);
 
        if (config->use_acpi1_thermal_zone_scope)
                scope = TZ_DEVICE_PATH;
        else
                scope = acpi_device_scope(dev);
 
        name = acpi_device_name(dev);
 
        assert(name);
        assert(scope);
 
        if (!config->temperature_controller) {
                printk(BIOS_ERR, "%s: missing temperature_controller\n", dev_path(dev));
                return;
        }
 
        printk(BIOS_INFO, "%s.%s: %s at %s\n", scope, name, dev->chip_ops->name, dev_path(dev));
 
        acpigen_write_scope(scope);
        acpigen_write_thermal_zone(name);
 
        if (config->description)
                acpigen_write_name_string("_STR", config->description);
 
        if (config->polling_period)
                acpigen_write_name_integer(
                        "_TZP", SECONDS_TO_DECI_SECONDS(config->polling_period));
 
        if (config->critical_temperature)
                acpigen_write_name_integer(
                        "_CRT", CELSIUS_TO_DECI_KELVIN(config->critical_temperature));
 
        if (config->hibernate_temperature)
                acpigen_write_name_integer(
                        "_HOT", CELSIUS_TO_DECI_KELVIN(config->hibernate_temperature));
 
        if (config->passive_config.temperature) {
                acpigen_write_name_integer(
                        "_PSV", CELSIUS_TO_DECI_KELVIN(config->passive_config.temperature));
 
                /*
                 * The linux kernel currently has an artificial limit of 10 on the number of
                 * references that can be returned in a list. If we don't respect this limit,
                 * then the passive threshold won't work.
                 *
                 * See https://source.chromium.org/chromiumos/chromiumos/codesearch/+/main:src/third_party/kernel/v5.10/include/acpi/acpi_bus.h;l=19
                 */
                acpigen_write_processor_package("_PSL", 0, MIN(10, dev_count_cpu()));
 
                acpigen_write_name_integer("_TC1", config->passive_config.time_constant_1
                                                           ?: DEFAULT_TC1);
                acpigen_write_name_integer("_TC2", config->passive_config.time_constant_2
                                                           ?: DEFAULT_TC2);
                acpigen_write_name_integer(
                        "_TSP",
                        SECONDS_TO_DECI_SECONDS(config->passive_config.time_sampling_period
                                                        ?: DEFAULT_TSP));
        }
 
        /*
         * Method (_TMP) {
         *   Return (<path>.TMP(<sensor_id>))
         * }
         */
        acpigen_write_method_serialized("_TMP", 0);
        acpigen_emit_byte(RETURN_OP);
        acpigen_emit_namestring(acpi_device_path_join(config->temperature_controller, "TMP"));
        acpigen_write_integer(config->sensor_id);
        acpigen_write_method_end();
 
        acpigen_write_thermal_zone_end();
        acpigen_write_scope_end();
}
 
static struct device_operations thermal_zone_ops = {
        .read_resources         = noop_read_resources,
        .set_resources          = noop_set_resources,
        .acpi_name              = thermal_zone_acpi_name,
        .acpi_fill_ssdt         = thermal_zone_fill_ssdt,
};
 
static void thermal_zone_enable_dev(struct device *dev)
{
        dev->ops = &thermal_zone_ops;
}
 
struct chip_operations drivers_acpi_thermal_zone_ops = {
        CHIP_NAME("ACPI Thermal Zone")
        .enable_dev = thermal_zone_enable_dev,
};