1 files changed, 111 insertions, 0 deletions
diff --git a/powerstats/DevfreqStateResidencyDataProvider.cpp b/powerstats/DevfreqStateResidencyDataProvider.cpp
new file mode 100644
index 0000000..d59e1e5
--- /dev/null
+++ b/powerstats/DevfreqStateResidencyDataProvider.cpp
@@ -0,0 +1,111 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include "DevfreqStateResidencyDataProvider.h"
+
+#include <android-base/logging.h>
+
+static const std::string nameSuffix = "-DVFS";
+static const std::string pathSuffix = "/time_in_state";
+
+namespace aidl {
+namespace android {
+namespace hardware {
+namespace power {
+namespace stats {
+
+DevfreqStateResidencyDataProvider::DevfreqStateResidencyDataProvider(const std::string& name,
+        const std::string& path) : mName(name + nameSuffix), mPath(path + pathSuffix) {}
+
+bool DevfreqStateResidencyDataProvider::extractNum(const char *str, char **str_end, int base,
+        int64_t* num) {
+    // errno can be set to any non-zero value by a library function call
+    // regardless of whether there was an error, so it needs to be cleared
+    // in order to check the error set by strtoll
+    errno = 0;
+    *num = std::strtoll(str, str_end, base);
+    return (errno != ERANGE);
+}
+
+std::vector<std::pair<int64_t, int64_t>> DevfreqStateResidencyDataProvider::parseTimeInState() {
+    // Using FILE* instead of std::ifstream for performance reasons
+    std::unique_ptr<FILE, decltype(&fclose)> fp(fopen(mPath.c_str(), "r"), fclose);
+    if (!fp) {
+        PLOG(ERROR) << "Failed to open file " << mPath;
+        return {};
+    }
+
+    std::vector<std::pair<int64_t, int64_t>> timeInState;
+
+    char *line = nullptr;
+    size_t len = 0;
+    while (getline(&line, &len, fp.get()) != -1) {
+        char* pEnd;
+        int64_t frequencyHz, totalTimeMs;
+        if (!extractNum(line, &pEnd, 10, &frequencyHz) ||
+            !extractNum(pEnd, &pEnd, 10, &totalTimeMs)) {
+            PLOG(ERROR) << "Failed to parse " << mPath;
+            free(line);
+            return {};
+        }
+
+        timeInState.push_back({frequencyHz, totalTimeMs});
+    }
+
+    free(line);
+    return timeInState;
+}
+
+bool DevfreqStateResidencyDataProvider::getStateResidencies(
+        std::unordered_map<std::string, std::vector<StateResidency>> *residencies) {
+    std::vector<std::pair<int64_t, int64_t>> timeInState = parseTimeInState();
+
+    if (timeInState.empty()) {
+        return false;
+    }
+
+    int32_t id = 0;
+    std::vector<StateResidency> stateResidencies;
+    for (const auto[frequencyHz, totalTimeMs] : timeInState) {
+        StateResidency s = {.id = id++, .totalTimeInStateMs = totalTimeMs};
+        stateResidencies.push_back(s);
+    }
+
+    residencies->emplace(mName, stateResidencies);
+    return true;
+}
+
+std::unordered_map<std::string, std::vector<State>> DevfreqStateResidencyDataProvider::getInfo() {
+    std::vector<std::pair<int64_t, int64_t>> timeInState = parseTimeInState();
+
+    if (timeInState.empty()) {
+        return {};
+    }
+
+    int32_t id = 0;
+    std::vector<State> states;
+    for (const auto[frequencyHz, totalTimeMs] : timeInState) {
+        State s = {.id = id++, .name = std::to_string(frequencyHz / 1000) + "MHz"};
+        states.push_back(s);
+    }
+
+    return {{mName, states}};
+}
+
+}  // namespace stats
+}  // namespace power
+}  // namespace hardware
+}  // namespace android
+}  // namespace aidl