ota_adafruit_ble.cpp

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#include "ota_adafruit_ble.h"
 
#if defined(USE_ZEPHYR) && defined(USE_NRF52)
#include "esphome/core/application.h"
#include "esphome/core/log.h"
 
#include <cstring>
#include <hal/nrf_power.h>
#include <zephyr/bluetooth/gatt.h>
 
namespace esphome::adafruit_ble {
 
ESPHOME_LOG_TAG(TAG, "adafruit_ble");
 
// Written by the upload tool (dfu.py) to ask for a restart into the bootloader,
// which then serves the DFU transfer. The bootloader only advertises its own DFU
// service while it is in DFU mode, so this service is what identifies the
// running application.
static constexpr uint8_t DFU_TRIGGER_MAGIC[] = {'D', 'F', 'U'};
// GPREGRET value the Adafruit nRF52 bootloader reads to enter OTA (BLE DFU) mode
static constexpr uint8_t DFU_GPREGRET_OTA = 0xA8;
 
// Matches the MCUmgr BLE transport default: a paired (authenticated) link once pairing is enabled
#ifdef CONFIG_BT_SMP
static constexpr uint16_t DFU_TRIGGER_PERM = BT_GATT_PERM_WRITE_AUTHEN;
#else
static constexpr uint16_t DFU_TRIGGER_PERM = BT_GATT_PERM_WRITE;
#endif
 
static OTAComponent *global_ota_component;  // NOLINT(cppcoreguidelines-avoid-non-const-global-variables)
 
static ssize_t dfu_trigger_write(struct bt_conn *conn, const struct bt_gatt_attr *attr, const void *buf, uint16_t len,
                                 uint16_t offset, uint8_t flags) {
  if (offset != 0) {
    return BT_GATT_ERR(BT_ATT_ERR_INVALID_OFFSET);
  }
  if (len != sizeof(DFU_TRIGGER_MAGIC) || memcmp(buf, DFU_TRIGGER_MAGIC, sizeof(DFU_TRIGGER_MAGIC)) != 0) {
    return BT_GATT_ERR(BT_ATT_ERR_VALUE_NOT_ALLOWED);
  }
  global_ota_component->request_dfu_mode();
  return len;
}
 
// Registered by bt_enable(), which zephyr_ble_server calls during its setup.
BT_GATT_SERVICE_DEFINE(  // NOLINT
    dfu_trigger_svc,
    BT_GATT_PRIMARY_SERVICE(BT_UUID_DECLARE_128(BT_UUID_128_ENCODE(0xe5b10001, 0x9c3a, 0x4f5d, 0x8a1b,
                                                                   0x2c3d4e5f6071))),
    BT_GATT_CHARACTERISTIC(BT_UUID_DECLARE_128(BT_UUID_128_ENCODE(0xe5b10002, 0x9c3a, 0x4f5d, 0x8a1b, 0x2c3d4e5f6071)),
                           BT_GATT_CHRC_WRITE, DFU_TRIGGER_PERM, nullptr, dfu_trigger_write, nullptr));
 
OTAComponent::OTAComponent() { global_ota_component = this; }
 
void OTAComponent::request_dfu_mode() {
  // Restart from the main loop, so the OTA listeners run there and the write is answered first
  this->defer([this]() {
    ESP_LOGI(TAG, "DFU mode requested, restarting into the bootloader");
#ifdef USE_OTA_STATE_LISTENER
    this->notify_state_(ota::OTA_STARTED, 0.0f, 0);
#endif
    // NOLINTNEXTLINE(clang-analyzer-core.FixedAddressDereference) -- NRF_POWER is MMIO at a fixed address
    NRF_POWER->GPREGRET = DFU_GPREGRET_OTA;
    App.reboot();
  });
}
 
void OTAComponent::dump_config() {
  ESP_LOGCONFIG(TAG, "Over-The-Air Updates:\n"
                     "  bootloader: Adafruit nRF52 (BLE DFU)");
}
 
}  // namespace esphome::adafruit_ble
#endif