esphome/esphome/components/uart/uart_component_esp8266.cpp

#ifdef USE_ESP8266
#include "uart_component_esp8266.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 {

static const char *const TAG = "uart";
// Edge decoder up to this baud rate; above it the start bit sampler, whose
// whole-byte block in the ISR is short there and whose timing still holds up.
static constexpr uint32_t SW_SERIAL_EDGE_MODE_MAX_BAUD = 38400;
bool ESP8266UartComponent::serial0_in_use = 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;
  } 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_);
  } 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
    );
  }
  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();
  }
}
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) {
  this->bit_time_ = F_CPU / baud_rate;
  this->rx_buffer_size_ = rx_buffer_size;
  this->stop_bits_ = stop_bits;
  this->data_bits_ = data_bits;
  this->parity_ = parity;
  this->rx_stop_bit_ = data_bits + (parity != UART_CONFIG_PARITY_NONE ? 1 : 0);
  // Runs longer than a whole frame plus one bit are idle; cap them there.
  this->rx_max_run_cycles_ = this->bit_time_ * (this->rx_stop_bit_ + stop_bits + 2);
  if (tx_pin != nullptr) {
    gpio_tx_pin_ = tx_pin;
    gpio_tx_pin_->setup();
    tx_pin_ = gpio_tx_pin_->to_isr();
    tx_pin_.digital_write(true);
  }
  if (rx_pin != nullptr) {
    gpio_rx_pin_ = rx_pin;
    gpio_rx_pin_->setup();
    rx_pin_ = gpio_rx_pin_->to_isr();
    if (this->rx_buffer_ == nullptr) {
      this->rx_buffer_ = new uint8_t[this->rx_buffer_size_];  // NOLINT
    }
    // load_settings() re-enters here, so reset the decoder before re-attaching.
    this->rx_bit_ = RX_IDLE;
    this->rx_last_level_ = this->rx_pin_.digital_read();
    this->rx_last_edge_ = arch_get_cpu_cycle_count();
    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);
    }
  }
}
inline bool ESPHOME_ALWAYS_INLINE ESP8266SoftwareSerial::rx_push_byte_(uint8_t data) {
  size_t in = this->rx_in_pos_;
  size_t next = in + 1;
  if (next == this->rx_buffer_size_)
    next = 0;
  if (next == this->rx_out_pos_)
    return false;  // full, drop the byte
  this->rx_buffer_[in] = data;
  this->rx_in_pos_ = next;
  return true;
}
void IRAM_ATTR ESP8266SoftwareSerial::gpio_intr(ESP8266SoftwareSerial *arg) {
  uint32_t wait = arg->bit_time_ + arg->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) << 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);

  // Stop bit
  arg->wait_(&wait, start);
  if (arg->stop_bits_ == 2)
    arg->wait_(&wait, start);

  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
}
inline bool ESPHOME_ALWAYS_INLINE ESP8266SoftwareSerial::rx_consume_run_(uint32_t bits, bool level) {
  uint8_t bit = this->rx_bit_;
  uint8_t cur = this->rx_cur_byte_;
  bool pushed = false;
  while (bits > 0) {
    if (bit == RX_IDLE) {
      // Idle line, or what is left of a run after a framing error.
      if (level)
        break;
      // Start bit
      bit = 0;
      cur = 0;
      bits--;
    } else if (bit < this->data_bits_) {
      uint8_t n = this->data_bits_ - bit;
      if (n > bits)
        n = bits;
      if (level)
        cur |= ((1U << n) - 1) << bit;
      bit += n;
      bits -= n;
    } else if (bit < this->rx_stop_bit_) {
      // Parity bit: consumed but not checked, same as gpio_intr.
      bit++;
      bits--;
    } else {
      // Stop bit; a low level here is a framing error, drop the byte.
      if (level)
        pushed = this->rx_push_byte_(cur);
      bit = RX_IDLE;
      break;
    }
  }
  this->rx_bit_ = bit;
  this->rx_cur_byte_ = cur;
  return pushed;
}
void IRAM_ATTR ESP8266SoftwareSerial::gpio_intr_edge(ESP8266SoftwareSerial *arg) {
  const uint32_t now = arch_get_cpu_cycle_count();
  const bool level = arg->rx_pin_.digital_read();
  const bool last_level = arg->rx_last_level_;
  // Two edges collapsed into one interrupt: skip it so the run is still
  // measured from the last real edge and the frame stays aligned.
  if (level == last_level)
    return;
  // Bits since the last edge, rounded to nearest; no hardware divider on the LX106, so count.
  uint32_t delta = now - arg->rx_last_edge_;
  if (delta > arg->rx_max_run_cycles_)
    delta = arg->rx_max_run_cycles_;
  delta += arg->bit_time_ / 2;
  uint32_t bits = 0;
  while (delta >= arg->bit_time_) {
    delta -= arg->bit_time_;
    bits++;
  }
  const bool pushed = arg->rx_consume_run_(bits, last_level);
  arg->rx_last_edge_ = now;
  arg->rx_last_level_ = level;
#ifdef USE_UART_WAKE_LOOP_ON_RX
  // A frame's last edge is always rising and its tail is completed by
  // rx_finalize_pending_() on the main loop, so wake on those as well.
  if (pushed || (level && arg->rx_bit_ != RX_IDLE))
    wake_loop_isrsafe();
#endif
}
void ESP8266SoftwareSerial::rx_finalize_pending_() {
  const uint8_t bit = this->rx_bit_;
  const uint32_t edge = this->rx_last_edge_;
  // Bits still needed up to and including the first stop bit.
  const uint32_t remaining = this->rx_stop_bit_ + 1 - bit;
  if (arch_get_cpu_cycle_count() - edge < remaining * this->bit_time_ + this->bit_time_ / 2) {
#ifdef USE_UART_WAKE_LOOP_ON_RX
    // Not old enough yet: run the loop again right away instead of after a full loop_interval_.
    wake_loop_threadsafe();
#endif
    return;
  }
  InterruptLock lock;
  // If the ISR moved on in the meantime the next call picks it up.
  if (this->rx_bit_ == bit && this->rx_last_edge_ == edge && this->rx_last_level_)
    this->rx_consume_run_(remaining, true);
}
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;
  }

  {
    InterruptLock lock;
    uint32_t wait = this->bit_time_;
    const uint32_t start = arch_get_cpu_cycle_count();
    // Start bit
    this->write_bit_(false, &wait, start);
    for (int i = 0; i < this->data_bits_; i++) {
      bool bit = data & (1 << i);
      this->write_bit_(bit, &wait, start);
      if (need_parity_bit)
        parity_bit ^= bit;
    }
    if (need_parity_bit)
      this->write_bit_(parity_bit, &wait, start);
    // Stop bit
    this->write_bit_(true, &wait, start);
    if (this->stop_bits_ == 2)
      this->wait_(&wait, start);
  }
}
void IRAM_ATTR ESP8266SoftwareSerial::wait_(uint32_t *wait, const uint32_t &start) {
  while (arch_get_cpu_cycle_count() - start < *wait)
    ;
  *wait += this->bit_time_;
}
bool IRAM_ATTR ESP8266SoftwareSerial::read_bit_(uint32_t *wait, const uint32_t &start) {
  this->wait_(wait, start);
  return this->rx_pin_.digital_read();
}
void IRAM_ATTR ESP8266SoftwareSerial::write_bit_(bool bit, uint32_t *wait, const uint32_t &start) {
  this->tx_pin_.digital_write(bit);
  this->wait_(wait, start);
}
uint8_t ESP8266SoftwareSerial::read_byte() {
  this->rx_sync_();
  if (this->rx_in_pos_ == this->rx_out_pos_)
    return 0;
  uint8_t data = this->rx_buffer_[this->rx_out_pos_];
  this->rx_out_pos_ = (this->rx_out_pos_ + 1) % this->rx_buffer_size_;
  return data;
}
uint8_t ESP8266SoftwareSerial::peek_byte() {
  this->rx_sync_();
  if (this->rx_in_pos_ == this->rx_out_pos_)
    return 0;
  return this->rx_buffer_[this->rx_out_pos_];
}
void ESP8266SoftwareSerial::flush() {
  // Flush is a NO-OP with software serial, all bytes are written immediately.
}
size_t ESP8266SoftwareSerial::available() {
  this->rx_sync_();
  // Read volatile rx_in_pos_ once to avoid TOCTOU race with ISR.
  // When in >= out, data is contiguous: [out..in).
  // When in < out, data wraps: [out..buf_size) + [0..in).
  size_t in = this->rx_in_pos_;
  if (in >= this->rx_out_pos_)
    return in - this->rx_out_pos_;
  return this->rx_buffer_size_ - this->rx_out_pos_ + in;
}

}  // namespace esphome::uart
#endif  // USE_ESP8266