src/drivers/acpi/thermal_zone/thermal_zone.c

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2
   3 #include <acpi/acpigen.h>
   4 #include <assert.h>
   5 #include <commonlib/bsd/helpers.h>
   6 #include <console/console.h>
   7 #include <device/device.h>
   8 #include <stdio.h>
   9 #include <stdlib.h>
  10
  11 #include "chip.h"
  12
  13 #define TZ_DEVICE_PATH  "\\_TZ"
  14 /* These defaults should be good enough for most systems */
  15 #define DEFAULT_TC1     2
  16 #define DEFAULT_TC2     5
  17 #define DEFAULT_TSP     10
  18
  19 #define CELSIUS_TO_DECI_KELVIN(temp_c)  ((temp_c) * 10 + 2732)
  20 #define SECONDS_TO_DECI_SECONDS(s)      ((s) * 10)
  21
  22 static const char *thermal_zone_acpi_name(const struct device *dev)
  23 {
  24         char *name;
  25
  26         if (dev->path.type != DEVICE_PATH_GENERIC)
  27                 return NULL;
  28
  29         name = malloc(ACPI_NAME_BUFFER_SIZE);
  30         snprintf(name, ACPI_NAME_BUFFER_SIZE, "TM%02X", dev->path.generic.id);
  31
  32         return name;
  33 }
  34
  35 static void thermal_zone_fill_ssdt(const struct device *dev)
  36 {
  37         struct drivers_acpi_thermal_zone_config *config = config_of(dev);
  38         const char *scope;
  39         const char *name;
  40
  41         assert(dev->path.type == DEVICE_PATH_GENERIC);
  42
  43         if (config->use_acpi1_thermal_zone_scope)
  44                 scope = TZ_DEVICE_PATH;
  45         else
  46                 scope = acpi_device_scope(dev);
  47
  48         name = acpi_device_name(dev);
  49
  50         assert(name);
  51         assert(scope);
  52
  53         if (!config->temperature_controller) {
  54                 printk(BIOS_ERR, "%s: missing temperature_controller\n", dev_path(dev));
  55                 return;
  56         }
  57
  58         printk(BIOS_INFO, "%s.%s: %s at %s\n", scope, name, dev->chip_ops->name, dev_path(dev));
  59
  60         acpigen_write_scope(scope);
  61         acpigen_write_thermal_zone(name);
  62
  63         if (config->description)
  64                 acpigen_write_name_unicode("_STR", config->description);
  65
  66         if (config->polling_period)
  67                 acpigen_write_name_integer(
  68                         "_TZP", SECONDS_TO_DECI_SECONDS(config->polling_period));
  69
  70         if (config->critical_temperature)
  71                 acpigen_write_name_integer(
  72                         "_CRT", CELSIUS_TO_DECI_KELVIN(config->critical_temperature));
  73
  74         if (config->hibernate_temperature)
  75                 acpigen_write_name_integer(
  76                         "_HOT", CELSIUS_TO_DECI_KELVIN(config->hibernate_temperature));
  77
  78         if (config->passive_config.temperature) {
  79                 acpigen_write_name_integer(
  80                         "_PSV", CELSIUS_TO_DECI_KELVIN(config->passive_config.temperature));
  81
  82                 /*
  83                  * The linux kernel currently has an artificial limit of 10 on the number of
  84                  * references that can be returned in a list. If we don't respect this limit,
  85                  * then the passive threshold won't work.
  86                  *
  87                  * See https://source.chromium.org/chromiumos/chromiumos/codesearch/+/main:src/third_party/kernel/v5.10/include/acpi/acpi_bus.h;l=19
  88                  */
  89                 acpigen_write_processor_package("_PSL", 0, MIN(10, dev_count_cpu()));
  90
  91                 acpigen_write_name_integer("_TC1", config->passive_config.time_constant_1
  92                                                            ?: DEFAULT_TC1);
  93                 acpigen_write_name_integer("_TC2", config->passive_config.time_constant_2
  94                                                            ?: DEFAULT_TC2);
  95                 acpigen_write_name_integer(
  96                         "_TSP",
  97                         SECONDS_TO_DECI_SECONDS(config->passive_config.time_sampling_period
  98                                                         ?: DEFAULT_TSP));
  99         }
 100
 101         /*
 102          * Method (_TMP) {
 103          *   Return (<path>.TMP(<sensor_id>))
 104          * }
 105          */
 106         acpigen_write_method_serialized("_TMP", 0);
 107         acpigen_emit_byte(RETURN_OP);
 108         acpigen_emit_namestring(acpi_device_path_join(config->temperature_controller, "TMP"));
 109         acpigen_write_integer(config->sensor_id);
 110         acpigen_write_method_end();
 111
 112         acpigen_write_thermal_zone_end();
 113         acpigen_write_scope_end();
 114 }
 115
 116 static struct device_operations thermal_zone_ops = {
 117         .read_resources         = noop_read_resources,
 118         .set_resources          = noop_set_resources,
 119         .acpi_name              = thermal_zone_acpi_name,
 120         .acpi_fill_ssdt         = thermal_zone_fill_ssdt,
 121 };
 122
 123 static void thermal_zone_enable_dev(struct device *dev)
 124 {
 125         dev->ops = &thermal_zone_ops;
 126 }
 127
 128 struct chip_operations drivers_acpi_thermal_zone_ops = {
 129         .name = "ACPI Thermal Zone",
 130         .enable_dev = thermal_zone_enable_dev,
 131 };