1 files changed, 73 insertions, 0 deletions
diff --git a/src/drivers/nvs.cpp b/src/drivers/nvs.cpp
new file mode 100644
index 00000000..a2de9518
--- /dev/null
+++ b/src/drivers/nvs.cpp
@@ -0,0 +1,73 @@
+/*
+ * Copyright 2023 jacqueline <me@jacqueline.id.au>
+ *
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+#include "nvs.hpp"
+#include <stdint.h>
+
+#include <cstdint>
+#include <memory>
+
+#include "esp_log.h"
+#include "nvs.h"
+#include "nvs_flash.h"
+
+namespace drivers {
+
+static constexpr char kTag[] = "nvm";
+static constexpr uint8_t kSchemaVersion = 1;
+
+static constexpr char kKeyVersion[] = "ver";
+
+auto NvsStorage::Open() -> NvsStorage* {
+  esp_err_t err = nvs_flash_init();
+  if (err == ESP_ERR_NVS_NO_FREE_PAGES) {
+    ESP_LOGW(kTag, "partition needs initialisation");
+    nvs_flash_erase();
+    err = nvs_flash_init();
+  }
+  if (err != ESP_OK) {
+    ESP_LOGE(kTag, "failed to init nvm");
+    return nullptr;
+  }
+
+  nvs_handle_t handle;
+  if ((err = nvs_open("tangara", NVS_READWRITE, &handle)) != ESP_OK) {
+    ESP_LOGE(kTag, "failed to open nvs namespace");
+    return nullptr;
+  }
+
+  std::unique_ptr<NvsStorage> instance = std::make_unique<NvsStorage>(handle);
+  if (instance->SchemaVersion() < kSchemaVersion) {
+    ESP_LOGW(kTag, "namespace needs downgrading");
+    nvs_erase_all(handle);
+    nvs_set_u8(handle, kKeyVersion, kSchemaVersion);
+    err = nvs_commit(handle);
+    if (err != ESP_OK) {
+      ESP_LOGW(kTag, "failed to init namespace");
+      return nullptr;
+    }
+  }
+
+  ESP_LOGI(kTag, "nvm storage initialised okay");
+  return instance.release();
+}
+
+NvsStorage::NvsStorage(nvs_handle_t handle) : handle_(handle) {}
+
+NvsStorage::~NvsStorage() {
+  nvs_close(handle_);
+  nvs_flash_deinit();
+}
+
+auto NvsStorage::SchemaVersion() -> uint8_t {
+  uint8_t ret;
+  if (nvs_get_u8(handle_, kKeyVersion, &ret) != ESP_OK) {
+    return UINT8_MAX;
+  }
+  return ret;
+}
+
+}  // namespace drivers