[power_sampler] Add sampling of CPU temperature via SMC.

Bug: 1254332
Change-Id: I182e694672048cf8d4fa78f40baebd47dd8ec2ae
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3312177
Reviewed-by: Etienne Pierre-Doray <etiennep@chromium.org>
Commit-Queue: Francois Pierre Doray <fdoray@chromium.org>
Cr-Commit-Position: refs/heads/main@{#947662}

components/power_metrics/smc_internal_types_mac.h

@@ -9,12 +9,17 @@
 #include <stdint.h>
 
 // List of known SMC key identifiers.
+//
+// This is a good reference: https://logi.wiki/index.php/SMC_Sensor_Codes
+// Additional keys can be discovered with
+// https://github.com/theopolis/smc-fuzzer
 enum class SMCKeyIdentifier : uint32_t {
-  TotalPower = 'PSTR',  // Power: System Total Rail (watts)
-  CPUPower = 'PCPC',    // Power: CPU Package CPU (watts)
-  iGPUPower = 'PCPG',   // Power: CPU Package GPU (watts)
-  GPU0Power = 'PG0R',   // Power: GPU 0 Rail (watts)
-  GPU1Power = 'PG1R',   // Power: GPU 1 Rail (watts)
+  TotalPower = 'PSTR',      // Power: System Total Rail (watts)
+  CPUPower = 'PCPC',        // Power: CPU Package CPU (watts)
+  iGPUPower = 'PCPG',       // Power: CPU Package GPU (watts)
+  GPU0Power = 'PG0R',       // Power: GPU 0 Rail (watts)
+  GPU1Power = 'PG1R',       // Power: GPU 1 Rail (watts)
+  CPUTemperature = 'TC0F',  // Temperature: CPU Die PECI (Celsius)
 };
 
 // Types from PowerManagement/pmconfigd/PrivateLib.c

components/power_metrics/smc_mac.h

@@ -13,6 +13,7 @@
 
 #include <memory>
 
+#include "base/containers/flat_map.h"
 #include "base/mac/scoped_ioobject.h"
 #include "components/power_metrics/smc_internal_types_mac.h"
 #include "third_party/abseil-cpp/absl/types/optional.h"
@@ -26,13 +27,9 @@ class SMCReader {
 
   virtual ~SMCReader();
 
-  // Returns the power consumption of various hardware components in watts.
+  // Returns the value of a key, or nullopt if not available.
   // Virtual for testing.
-  virtual absl::optional<double> ReadTotalPowerW();
-  virtual absl::optional<double> ReadCPUPackageCPUPowerW();
-  virtual absl::optional<double> ReadCPUPackageGPUPowerW();
-  virtual absl::optional<double> ReadGPU0PowerW();
-  virtual absl::optional<double> ReadGPU1PowerW();
+  virtual absl::optional<double> ReadKey(SMCKeyIdentifier identifier);
 
  protected:
   explicit SMCReader(base::mac::ScopedIOObject<io_object_t> connect);
@@ -42,6 +39,8 @@ class SMCReader {
    public:
     SMCKey(base::mac::ScopedIOObject<io_object_t> connect,
            SMCKeyIdentifier key_identifier);
+    SMCKey(SMCKey&&);
+    SMCKey& operator=(SMCKey&&);
     ~SMCKey();
 
     bool Exists() const;
@@ -51,15 +50,12 @@ class SMCReader {
     bool CallSMCFunction(uint8_t function, SMCParamStruct* out);
 
     base::mac::ScopedIOObject<io_object_t> connect_;
-    const SMCKeyIdentifier key_identifier_;
+    SMCKeyIdentifier key_identifier_;
     SMCKeyInfoData key_info_;
   };
 
-  SMCKey total_power_key_;
-  SMCKey cpu_package_cpu_power_key_;
-  SMCKey cpu_package_gpu_power_key_;
-  SMCKey gpu0_power_key_;
-  SMCKey gpu1_power_key_;
+  base::mac::ScopedIOObject<io_object_t> connect_;
+  base::flat_map<SMCKeyIdentifier, SMCKey> keys_;
 };
 
 }  // namespace power_metrics

components/power_metrics/smc_mac.mm

@@ -35,24 +35,14 @@ std::unique_ptr<SMCReader> SMCReader::Create() {
 
 SMCReader::~SMCReader() = default;
 
-absl::optional<double> SMCReader::ReadTotalPowerW() {
-  return total_power_key_.Read();
-}
+absl::optional<double> SMCReader::ReadKey(SMCKeyIdentifier identifier) {
+  auto it = keys_.find(identifier);
+  if (it == keys_.end()) {
+    auto result = keys_.emplace(identifier, SMCKey(connect_, identifier));
+    it = result.first;
+  }
 
-absl::optional<double> SMCReader::ReadCPUPackageCPUPowerW() {
-  return cpu_package_cpu_power_key_.Read();
-}
-
-absl::optional<double> SMCReader::ReadCPUPackageGPUPowerW() {
-  return cpu_package_gpu_power_key_.Read();
-}
-
-absl::optional<double> SMCReader::ReadGPU0PowerW() {
-  return gpu0_power_key_.Read();
-}
-
-absl::optional<double> SMCReader::ReadGPU1PowerW() {
-  return gpu1_power_key_.Read();
+  return it->second.Read();
 }
 
 SMCReader::SMCKey::SMCKey(base::mac::ScopedIOObject<io_object_t> connect,
@@ -64,6 +54,9 @@ SMCReader::SMCKey::SMCKey(base::mac::ScopedIOObject<io_object_t> connect,
     key_info_ = out.keyInfo;
 }
 
+SMCReader::SMCKey::SMCKey(SMCKey&&) = default;
+SMCReader::SMCKey& SMCReader::SMCKey::operator=(SMCKey&&) = default;
+
 SMCReader::SMCKey::~SMCKey() = default;
 
 bool SMCReader::SMCKey::Exists() const {
@@ -125,10 +118,6 @@ bool SMCReader::SMCKey::CallSMCFunction(uint8_t function, SMCParamStruct* out) {
 }
 
 SMCReader::SMCReader(base::mac::ScopedIOObject<io_object_t> connect)
-    : total_power_key_(connect, SMCKeyIdentifier::TotalPower),
-      cpu_package_cpu_power_key_(connect, SMCKeyIdentifier::CPUPower),
-      cpu_package_gpu_power_key_(connect, SMCKeyIdentifier::iGPUPower),
-      gpu0_power_key_(connect, SMCKeyIdentifier::GPU0Power),
-      gpu1_power_key_(connect, SMCKeyIdentifier::GPU1Power) {}
+    : connect_(std::move(connect)) {}
 
 }  // namespace power_metrics