uart_component_esp8266.cpp

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#ifdef USE_ESP8266
#include "uart_component_esp8266.h"
#include <esp8266_peri.h>
#include "esphome/core/application.h"
#include "esphome/core/defines.h"
#include "esphome/core/helpers.h"
#include "esphome/core/log.h"
#ifdef USE_UART_WAKE_LOOP_ON_RX
#include "esphome/core/wake.h"
#endif
 
#ifdef USE_LOGGER
#include "esphome/components/logger/logger.h"
#endif
 
namespace esphome::uart {
 
ESPHOME_LOG_TAG(TAG, "uart");
// Edge decoder up to this baud rate; at 38400 WiFi interrupt latency corrupts bytes.
static constexpr uint32_t SW_SERIAL_EDGE_MODE_MAX_BAUD = 19200;
// Edge decoder time base: 1/16 us from the 1 MHz system timer, which keeps its rate during a
// CpuFrequencyBoost; the cycle counter does not.
static constexpr uint32_t RX_TICKS_PER_SECOND = 16000000;
__attribute__((always_inline)) static inline uint32_t rx_now() { return micros() << 4; }
bool ESP8266UartComponent::serial0_in_use = false;  // NOLINT(cppcoreguidelines-avoid-non-const-global-variables)
 
bool ESP8266UartComponent::serial0_swapped = false;  // NOLINT(cppcoreguidelines-avoid-non-const-global-variables)
 
uint32_t ESP8266UartComponent::get_config() {
  uint32_t config = 0;
 
  if (this->parity_ == UART_CONFIG_PARITY_NONE) {
    config |= UART_PARITY_NONE;
  } else if (this->parity_ == UART_CONFIG_PARITY_EVEN) {
    config |= UART_PARITY_EVEN;
  } else if (this->parity_ == UART_CONFIG_PARITY_ODD) {
    config |= UART_PARITY_ODD;
  }
 
  switch (this->data_bits_) {
    case 5:
      config |= UART_NB_BIT_5;
      break;
    case 6:
      config |= UART_NB_BIT_6;
      break;
    case 7:
      config |= UART_NB_BIT_7;
      break;
    case 8:
      config |= UART_NB_BIT_8;
      break;
  }
 
  if (this->stop_bits_ == 1) {
    config |= UART_NB_STOP_BIT_1;
  } else {
    config |= UART_NB_STOP_BIT_2;
  }
 
  if (this->tx_pin_ != nullptr && this->tx_pin_->is_inverted())
    config |= BIT(22);
  if (this->rx_pin_ != nullptr && this->rx_pin_->is_inverted())
    config |= BIT(19);
 
  return config;
}
 
void ESP8266UartComponent::setup() {
  auto setup_pin_if_needed = [](InternalGPIOPin *pin) {
    if (!pin) {
      return;
    }
    const auto mask = gpio::Flags::FLAG_OPEN_DRAIN | gpio::Flags::FLAG_PULLUP | gpio::Flags::FLAG_PULLDOWN;
    if ((pin->get_flags() & mask) != gpio::Flags::FLAG_NONE) {
      pin->setup();
    }
  };
 
  setup_pin_if_needed(this->rx_pin_);
  if (this->rx_pin_ != this->tx_pin_) {
    setup_pin_if_needed(this->tx_pin_);
  }
 
  // Use Arduino HardwareSerial UARTs if all used pins match the ones
  // preconfigured by the platform. For example if RX disabled but TX pin
  // is 1 we still want to use Serial.
  SerialConfig config = static_cast<SerialConfig>(get_config());
 
#ifdef USE_ESP8266_UART_SERIAL
  if (!ESP8266UartComponent::serial0_in_use && (tx_pin_ == nullptr || tx_pin_->get_pin() == 1) &&
      (rx_pin_ == nullptr || rx_pin_->get_pin() == 3)
#ifdef USE_LOGGER
      // we will use UART0 if logger isn't using it in swapped mode
      && (logger::global_logger->get_hw_serial() == nullptr ||
          logger::global_logger->get_uart() != logger::UART_SELECTION_UART0_SWAP)
#endif
  ) {
    this->hw_serial_ = &Serial;
    this->hw_serial_->begin(this->baud_rate_, config);
    this->hw_serial_->setRxBufferSize(this->rx_buffer_size_);
    ESP8266UartComponent::serial0_in_use = true;
  } else if (!ESP8266UartComponent::serial0_in_use && (tx_pin_ == nullptr || tx_pin_->get_pin() == 15) &&
             (rx_pin_ == nullptr || rx_pin_->get_pin() == 13)
#ifdef USE_LOGGER
             // we will use UART0 swapped if logger isn't using it in regular mode
             && (logger::global_logger->get_hw_serial() == nullptr ||
                 logger::global_logger->get_uart() != logger::UART_SELECTION_UART0)
#endif
  ) {
    this->hw_serial_ = &Serial;
    this->hw_serial_->begin(this->baud_rate_, config);
    this->hw_serial_->setRxBufferSize(this->rx_buffer_size_);
    this->hw_serial_->swap();
    ESP8266UartComponent::serial0_in_use = true;
    ESP8266UartComponent::serial0_swapped = true;
  } else
#endif  // USE_ESP8266_UART_SERIAL
#ifdef USE_ESP8266_UART_SERIAL1
      if ((tx_pin_ == nullptr || tx_pin_->get_pin() == 2) && (rx_pin_ == nullptr || rx_pin_->get_pin() == 8)) {
    this->hw_serial_ = &Serial1;
    this->hw_serial_->begin(this->baud_rate_, config);
    this->hw_serial_->setRxBufferSize(this->rx_buffer_size_);
  } else
#endif  // USE_ESP8266_UART_SERIAL1
  {
    this->sw_serial_ = new ESP8266SoftwareSerial();  // NOLINT
    this->sw_serial_->setup(tx_pin_, rx_pin_, this->baud_rate_, this->stop_bits_, this->data_bits_, this->parity_,
                            this->rx_buffer_size_);
  }
}
 
void ESP8266UartComponent::load_settings(bool dump_config) {
  ESP_LOGCONFIG(TAG, "Loading UART bus settings");
  if (this->hw_serial_ != nullptr) {
    SerialConfig config = static_cast<SerialConfig>(get_config());
    this->hw_serial_->begin(this->baud_rate_, config);
    this->hw_serial_->setRxBufferSize(this->rx_buffer_size_);
#ifdef USE_ESP8266_UART_SERIAL
    // begin() puts UART0 back on GPIO1/GPIO3, so swap it again like setup() did for GPIO15/GPIO13
    if (this->hw_serial_ == &Serial && ESP8266UartComponent::serial0_swapped)
      this->hw_serial_->swap();
#endif  // USE_ESP8266_UART_SERIAL
  } else {
    this->sw_serial_->setup(this->tx_pin_, this->rx_pin_, this->baud_rate_, this->stop_bits_, this->data_bits_,
                            this->parity_, this->rx_buffer_size_);
  }
  if (dump_config) {
    ESP_LOGCONFIG(TAG, "UART bus was reloaded.");
    this->dump_config();
  }
}
 
void ESP8266UartComponent::dump_config() {
  ESP_LOGCONFIG(TAG, "UART Bus:");
  LOG_PIN("  TX Pin: ", this->tx_pin_);
  LOG_PIN("  RX Pin: ", this->rx_pin_);
  if (this->rx_pin_ != nullptr) {
    ESP_LOGCONFIG(TAG, "  RX Buffer Size: %u", this->rx_buffer_size_);  // NOLINT
  }
  ESP_LOGCONFIG(TAG,
                "  Baud Rate: %u baud\n"
                "  Data Bits: %u\n"
                "  Parity: %s\n"
                "  Stop bits: %u",
                this->baud_rate_, this->data_bits_, LOG_STR_ARG(parity_to_str(this->parity_)), this->stop_bits_);
  if (this->hw_serial_ != nullptr) {
    ESP_LOGCONFIG(TAG, "  Using hardware serial interface.");
  } else {
    ESP_LOGCONFIG(TAG, "  Using software serial"
#ifdef USE_UART_WAKE_LOOP_ON_RX
                       "\n  Wake on data RX: ENABLED"
#endif
    );
    if (this->rx_pin_ != nullptr) {
      ESP_LOGCONFIG(TAG, "  RX decoder: %s",
                    this->baud_rate_ <= SW_SERIAL_EDGE_MODE_MAX_BAUD ? LOG_STR_LITERAL("edge")
                                                                     : LOG_STR_LITERAL("start bit sampler"));
    }
  }
  this->check_logger_conflict();
}
 
void ESP8266UartComponent::check_logger_conflict() {
#ifdef USE_LOGGER
  if (this->hw_serial_ == nullptr || logger::global_logger->get_baud_rate() == 0) {
    return;
  }
 
  if (this->hw_serial_ == logger::global_logger->get_hw_serial()) {
    ESP_LOGW(TAG, "  You're using the same serial port for logging and the UART component. Please "
                  "disable logging over the serial port by setting logger->baud_rate to 0.");
  }
#endif
}
 
void ESP8266UartComponent::write_array(const uint8_t *data, size_t len) {
  if (this->hw_serial_ != nullptr) {
    this->hw_serial_->write(data, len);
  } else {
    for (size_t i = 0; i < len; i++)
      this->sw_serial_->write_byte(data[i]);
  }
#ifdef USE_UART_DEBUGGER
  for (size_t i = 0; i < len; i++) {
    this->debug_callback_.call(UART_DIRECTION_TX, data[i]);
  }
#endif
}
bool ESP8266UartComponent::peek_byte(uint8_t *data) {
  if (!this->check_read_timeout_())
    return false;
  if (this->hw_serial_ != nullptr) {
    *data = this->hw_serial_->peek();
  } else {
    *data = this->sw_serial_->peek_byte();
  }
  return true;
}
bool ESP8266UartComponent::read_array(uint8_t *data, size_t len) {
  if (!this->check_read_timeout_(len))
    return false;
  if (this->hw_serial_ != nullptr) {
    this->hw_serial_->readBytes(data, len);
  } else {
    for (size_t i = 0; i < len; i++)
      data[i] = this->sw_serial_->read_byte();
  }
#ifdef USE_UART_DEBUGGER
  for (size_t i = 0; i < len; i++) {
    this->debug_callback_.call(UART_DIRECTION_RX, data[i]);
  }
#endif
  return true;
}
size_t ESP8266UartComponent::available() {
  if (this->hw_serial_ != nullptr) {
    return this->hw_serial_->available();
  } else {
    return this->sw_serial_->available();
  }
}
size_t ESP8266UartComponent::available_for_write() {
  if (this->hw_serial_ != nullptr) {
    return this->hw_serial_->availableForWrite();
  }
  return SIZE_MAX;  // software serial bit-bangs each byte synchronously; there is no buffer to fill
}
UARTFlushResult ESP8266UartComponent::flush() {
  ESP_LOGVV(TAG, "    Flushing");
  if (this->hw_serial_ != nullptr) {
    this->hw_serial_->flush();
  } else {
    this->sw_serial_->flush();
  }
  return UARTFlushResult::UART_FLUSH_RESULT_ASSUMED_SUCCESS;
}
void ESP8266SoftwareSerial::setup(InternalGPIOPin *tx_pin, InternalGPIOPin *rx_pin, uint32_t baud_rate,
                                  uint8_t stop_bits, uint32_t data_bits, UARTParityOptions parity,
                                  size_t rx_buffer_size) {
  // load_settings() re-enters here
  if (this->gpio_rx_pin_ != nullptr)
    this->gpio_rx_pin_->detach_interrupt();
  this->bit_time_ = F_CPU / baud_rate;
  this->stop_bits_ = stop_bits;
  this->data_bits_ = data_bits;
  this->parity_ = parity;
  // to_isr() allocates, so call it only for a new or changed pin
  if (tx_pin != nullptr) {
    if (tx_pin != this->gpio_tx_pin_)
      this->tx_pin_ = tx_pin->to_isr();
    gpio_tx_pin_ = tx_pin;
    gpio_tx_pin_->setup();
    tx_pin_.digital_write(true);
  }
  if (rx_pin != nullptr) {
    if (rx_pin != this->gpio_rx_pin_)
      this->rx_pin_ = rx_pin->to_isr();
    gpio_rx_pin_ = rx_pin;
    gpio_rx_pin_->setup();
    uint8_t *buffer = this->rx_.buffer();
    if (this->rx_.buffer_size() != rx_buffer_size) {
      delete[] buffer;                       // NOLINT
      buffer = new uint8_t[rx_buffer_size];  // NOLINT
    }
    this->rx_.setup((RX_TICKS_PER_SECOND + baud_rate / 2) / baud_rate, data_bits, parity != UART_CONFIG_PARITY_NONE,
                    stop_bits, buffer, rx_buffer_size);
    this->rx_.reset(rx_now(), this->rx_pin_.digital_read());
    if (baud_rate <= SW_SERIAL_EDGE_MODE_MAX_BAUD) {
      gpio_rx_pin_->attach_interrupt(ESP8266SoftwareSerial::gpio_intr_edge, this, gpio::INTERRUPT_ANY_EDGE);
    } else {
      gpio_rx_pin_->attach_interrupt(ESP8266SoftwareSerial::gpio_intr, this, gpio::INTERRUPT_FALLING_EDGE);
    }
  }
}
// A byte can arrive while a CpuFrequencyBoost has an 80 MHz build at 160 MHz; the clock select bit doubles
// the bit time then. The whole byte is read inside the ISR, so the clock cannot change partway through.
__attribute__((always_inline)) static inline uint32_t rx_bit_time(uint32_t bit_time) {
#if F_CPU != 160000000L
  // NOLINTNEXTLINE(clang-analyzer-core.FixedAddressDereference) -- CPU2X is MMIO at a fixed address
  return bit_time << (CPU2X & 1);
#else
  return bit_time;
#endif
}
 
void IRAM_ATTR ESP8266SoftwareSerial::gpio_intr(ESP8266SoftwareSerial *arg) {
  const uint32_t bit_time = rx_bit_time(arg->bit_time_);
  uint32_t wait = bit_time + bit_time / 3 - 500;
  const uint32_t start = arch_get_cpu_cycle_count();
  uint8_t rec = 0;
  // Manually unroll the loop
  for (int i = 0; i < arg->data_bits_; i++)
    rec |= arg->read_bit_(&wait, start, bit_time) << i;
 
  /* If parity is enabled, just read it and ignore it. */
  /* TODO: Should we check parity? Or is it too slow for nothing added..*/
  if (arg->parity_ == UART_CONFIG_PARITY_EVEN || arg->parity_ == UART_CONFIG_PARITY_ODD)
    arg->read_bit_(&wait, start, bit_time);
 
  // Stop bit
  arg->wait_(&wait, start, bit_time);
  if (arg->stop_bits_ == 2)
    arg->wait_(&wait, start, bit_time);
 
  arg->rx_.push_byte(rec);
  // Clear RX pin so that the interrupt doesn't re-trigger right away again.
  arg->rx_pin_.clear_interrupt();
#ifdef USE_UART_WAKE_LOOP_ON_RX
  // Wake the main loop so the consuming component drains the byte promptly
  // instead of waiting for the next loop_interval_ tick. Important for timing
  // sensitive setups that poll read() in a tight loop (e.g. fingerprint_grow).
  wake_loop_isrsafe();
#endif
}
void IRAM_ATTR ESP8266SoftwareSerial::gpio_intr_edge(ESP8266SoftwareSerial *arg) {
  const uint32_t now = rx_now();
  const bool level = arg->rx_pin_.digital_read();
  [[maybe_unused]] const bool wake = arg->rx_.on_edge(now, level);
#ifdef USE_UART_WAKE_LOOP_ON_RX
  if (wake)
    wake_loop_isrsafe();
#endif
}
void ESP8266SoftwareSerial::rx_finalize_pending_() {
  if (!this->rx_.finalize_due(rx_now())) {
#ifdef USE_UART_WAKE_LOOP_ON_RX
    // Tail not elapsed; wake again only once drained
    if (this->rx_.available() == 0)
      wake_loop_threadsafe();
#endif
    return;
  }
  InterruptLock lock;
  this->rx_.finalize(rx_now());
}
void IRAM_ATTR HOT ESP8266SoftwareSerial::write_byte(uint8_t data) {
  if (this->gpio_tx_pin_ == nullptr) {
    ESP_LOGE(TAG, "UART doesn't have TX pins set!");
    return;
  }
  bool parity_bit = false;
  bool need_parity_bit = true;
  if (this->parity_ == UART_CONFIG_PARITY_EVEN) {
    parity_bit = false;
  } else if (this->parity_ == UART_CONFIG_PARITY_ODD) {
    parity_bit = true;
  } else {
    need_parity_bit = false;
  }
 
  {
    // Transmit runs from the main loop and never overlaps a CpuFrequencyBoost
    InterruptLock lock;
    const uint32_t bit_time = this->bit_time_;
    uint32_t wait = bit_time;
    const uint32_t start = arch_get_cpu_cycle_count();
    // Start bit
    this->write_bit_(false, &wait, start, bit_time);
    for (int i = 0; i < this->data_bits_; i++) {
      bool bit = data & (1 << i);
      this->write_bit_(bit, &wait, start, bit_time);
      if (need_parity_bit)
        parity_bit ^= bit;
    }
    if (need_parity_bit)
      this->write_bit_(parity_bit, &wait, start, bit_time);
    // Stop bit
    this->write_bit_(true, &wait, start, bit_time);
    if (this->stop_bits_ == 2)
      this->wait_(&wait, start, bit_time);
  }
}
void IRAM_ATTR ESP8266SoftwareSerial::wait_(uint32_t *wait, const uint32_t &start, uint32_t bit_time) {
  while (arch_get_cpu_cycle_count() - start < *wait)
    ;
  *wait += bit_time;
}
bool IRAM_ATTR ESP8266SoftwareSerial::read_bit_(uint32_t *wait, const uint32_t &start, uint32_t bit_time) {
  this->wait_(wait, start, bit_time);
  return this->rx_pin_.digital_read();
}
void IRAM_ATTR ESP8266SoftwareSerial::write_bit_(bool bit, uint32_t *wait, const uint32_t &start, uint32_t bit_time) {
  this->tx_pin_.digital_write(bit);
  this->wait_(wait, start, bit_time);
}
uint8_t ESP8266SoftwareSerial::read_byte() {
  this->rx_sync_();
  return this->rx_.read_byte();
}
uint8_t ESP8266SoftwareSerial::peek_byte() {
  this->rx_sync_();
  return this->rx_.peek_byte();
}
void ESP8266SoftwareSerial::flush() {
  // Flush is a NO-OP with software serial, all bytes are written immediately.
}
size_t ESP8266SoftwareSerial::available() {
  this->rx_sync_();
  return this->rx_.available();
}
 
}  // namespace esphome::uart
#endif  // USE_ESP8266