1 files changed, 131 insertions, 0 deletions
diff --git a/src/drivers/acpi/thermal_zone/thermal_zone.c b/src/drivers/acpi/thermal_zone/thermal_zone.c
new file mode 100644
index 0000000000..1a52997607
--- /dev/null
+++ b/src/drivers/acpi/thermal_zone/thermal_zone.c
@@ -0,0 +1,131 @@
+/* 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,
+};