dfplayer: batch UART reads to reduce per-loop overhead

esphome/components/cse7766/cse7766.cpp

@@ -7,6 +7,7 @@ namespace esphome {
 namespace cse7766 {
 
 static const char *const TAG = "cse7766";
+static constexpr size_t CSE7766_RAW_DATA_SIZE = 24;
 
 void CSE7766Component::loop() {
   const uint32_t now = App.get_loop_component_start_time();
@@ -15,38 +16,25 @@ void CSE7766Component::loop() {
     this->raw_data_index_ = 0;
   }
 
-  int avail = this->available();
-  if (avail == 0) {
+  if (this->available() == 0) {
     return;
   }
 
   this->last_transmission_ = now;
-
-  // Read all available bytes in batches to reduce UART call overhead.
-  // At 4800 baud (~480 bytes/sec) with ~122 Hz loop rate, typically ~4 bytes per call.
-  uint8_t buf[CSE7766_RAW_DATA_SIZE];
-  while (avail > 0) {
-    size_t to_read = std::min(static_cast<size_t>(avail), sizeof(buf));
-    if (!this->read_array(buf, to_read)) {
-      break;
+  while (this->available() != 0) {
+    this->read_byte(&this->raw_data_[this->raw_data_index_]);
+    if (!this->check_byte_()) {
+      this->raw_data_index_ = 0;
+      this->status_set_warning();
+      continue;
     }
-    avail -= to_read;
 
-    for (size_t i = 0; i < to_read; i++) {
-      this->raw_data_[this->raw_data_index_] = buf[i];
-      if (!this->check_byte_()) {
-        this->raw_data_index_ = 0;
-        this->status_set_warning();
-        continue;
-      }
-
-      if (this->raw_data_index_ == CSE7766_RAW_DATA_SIZE - 1) {
-        this->parse_data_();
-        this->status_clear_warning();
-      }
-
-      this->raw_data_index_ = (this->raw_data_index_ + 1) % CSE7766_RAW_DATA_SIZE;
+    if (this->raw_data_index_ == 23) {
+      this->parse_data_();
+      this->status_clear_warning();
     }
+
+    this->raw_data_index_ = (this->raw_data_index_ + 1) % 24;
   }
 }
 
@@ -65,15 +53,14 @@ bool CSE7766Component::check_byte_() {
     return true;
   }
 
-  if (index == CSE7766_RAW_DATA_SIZE - 1) {
+  if (index == 23) {
     uint8_t checksum = 0;
-    for (uint8_t i = 2; i < CSE7766_RAW_DATA_SIZE - 1; i++) {
+    for (uint8_t i = 2; i < 23; i++) {
       checksum += this->raw_data_[i];
     }
 
-    if (checksum != this->raw_data_[CSE7766_RAW_DATA_SIZE - 1]) {
-      ESP_LOGW(TAG, "Invalid checksum from CSE7766: 0x%02X != 0x%02X", checksum,
-               this->raw_data_[CSE7766_RAW_DATA_SIZE - 1]);
+    if (checksum != this->raw_data_[23]) {
+      ESP_LOGW(TAG, "Invalid checksum from CSE7766: 0x%02X != 0x%02X", checksum, this->raw_data_[23]);
       return false;
     }
     return true;

esphome/components/cse7766/cse7766.h

@@ -8,8 +8,6 @@
 namespace esphome {
 namespace cse7766 {
 
-static constexpr size_t CSE7766_RAW_DATA_SIZE = 24;
-
 class CSE7766Component : public Component, public uart::UARTDevice {
  public:
   void set_voltage_sensor(sensor::Sensor *voltage_sensor) { voltage_sensor_ = voltage_sensor; }
@@ -35,7 +33,7 @@ class CSE7766Component : public Component, public uart::UARTDevice {
                          this->raw_data_[start_index + 2]);
   }
 
-  uint8_t raw_data_[CSE7766_RAW_DATA_SIZE];
+  uint8_t raw_data_[24];
   uint8_t raw_data_index_{0};
   uint32_t last_transmission_{0};
   sensor::Sensor *voltage_sensor_{nullptr};

esphome/components/dfplayer/dfplayer.cpp

@@ -1,4 +1,5 @@
 #include "dfplayer.h"
+#include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 
 namespace esphome {
@@ -132,139 +133,151 @@ void DFPlayer::send_cmd_(uint8_t cmd, uint16_t argument) {
 
 void DFPlayer::loop() {
   // Read message
-  while (this->available()) {
-    uint8_t byte;
-    this->read_byte(&byte);
+  int avail = this->available();
+  if (avail <= 0)
+    return;
 
-    if (this->read_pos_ == DFPLAYER_READ_BUFFER_LENGTH)
-      this->read_pos_ = 0;
-
-    switch (this->read_pos_) {
-      case 0:  // Start mark
-        if (byte != 0x7E)
-          continue;
-        break;
-      case 1:  // Version
-        if (byte != 0xFF) {
-          ESP_LOGW(TAG, "Expected Version 0xFF, got %#02x", byte);
-          this->read_pos_ = 0;
-          continue;
-        }
-        break;
-      case 2:  // Buffer length
-        if (byte != 0x06) {
-          ESP_LOGW(TAG, "Expected Buffer length 0x06, got %#02x", byte);
-          this->read_pos_ = 0;
-          continue;
-        }
-        break;
-      case 9:  // End byte
-#ifdef ESPHOME_LOG_HAS_VERY_VERBOSE
-        char byte_sequence[100];
-        byte_sequence[0] = '\0';
-        for (size_t i = 0; i < this->read_pos_ + 1; ++i) {
-          snprintf(byte_sequence + strlen(byte_sequence), sizeof(byte_sequence) - strlen(byte_sequence), "%02X ",
-                   this->read_buffer_[i]);
-        }
-        ESP_LOGVV(TAG, "Received byte sequence: %s", byte_sequence);
-#endif
-        if (byte != 0xEF) {
-          ESP_LOGW(TAG, "Expected end byte 0xEF, got %#02x", byte);
-          this->read_pos_ = 0;
-          continue;
-        }
-        // Parse valid received command
-        uint8_t cmd = this->read_buffer_[3];
-        uint16_t argument = (this->read_buffer_[5] << 8) | this->read_buffer_[6];
-
-        ESP_LOGV(TAG, "Received message cmd: %#02x arg %#04x", cmd, argument);
-
-        switch (cmd) {
-          case 0x3A:
-            if (argument == 1) {
-              ESP_LOGI(TAG, "USB loaded");
-            } else if (argument == 2) {
-              ESP_LOGI(TAG, "TF Card loaded");
-            }
-            break;
-          case 0x3B:
-            if (argument == 1) {
-              ESP_LOGI(TAG, "USB unloaded");
-            } else if (argument == 2) {
-              ESP_LOGI(TAG, "TF Card unloaded");
-            }
-            break;
-          case 0x3F:
-            if (argument == 1) {
-              ESP_LOGI(TAG, "USB available");
-            } else if (argument == 2) {
-              ESP_LOGI(TAG, "TF Card available");
-            } else if (argument == 3) {
-              ESP_LOGI(TAG, "USB, TF Card available");
-            }
-            break;
-          case 0x40:
-            ESP_LOGV(TAG, "Nack");
-            this->ack_set_is_playing_ = false;
-            this->ack_reset_is_playing_ = false;
-            switch (argument) {
-              case 0x01:
-                ESP_LOGE(TAG, "Module is busy or uninitialized");
-                break;
-              case 0x02:
-                ESP_LOGE(TAG, "Module is in sleep mode");
-                break;
-              case 0x03:
-                ESP_LOGE(TAG, "Serial receive error");
-                break;
-              case 0x04:
-                ESP_LOGE(TAG, "Checksum incorrect");
-                break;
-              case 0x05:
-                ESP_LOGE(TAG, "Specified track is out of current track scope");
-                this->is_playing_ = false;
-                break;
-              case 0x06:
-                ESP_LOGE(TAG, "Specified track is not found");
-                this->is_playing_ = false;
-                break;
-              case 0x07:
-                ESP_LOGE(TAG, "Insertion error (an inserting operation only can be done when a track is being played)");
-                break;
-              case 0x08:
-                ESP_LOGE(TAG, "SD card reading failed (SD card pulled out or damaged)");
-                break;
-              case 0x09:
-                ESP_LOGE(TAG, "Entered into sleep mode");
-                this->is_playing_ = false;
-                break;
-            }
-            break;
-          case 0x41:
-            ESP_LOGV(TAG, "Ack ok");
-            this->is_playing_ |= this->ack_set_is_playing_;
-            this->is_playing_ &= !this->ack_reset_is_playing_;
-            this->ack_set_is_playing_ = false;
-            this->ack_reset_is_playing_ = false;
-            break;
-          case 0x3C:
-            ESP_LOGV(TAG, "Playback finished (USB drive)");
-            this->is_playing_ = false;
-            this->on_finished_playback_callback_.call();
-          case 0x3D:
-            ESP_LOGV(TAG, "Playback finished (SD card)");
-            this->is_playing_ = false;
-            this->on_finished_playback_callback_.call();
-            break;
-          default:
-            ESP_LOGE(TAG, "Received unknown cmd %#02x arg %#04x", cmd, argument);
-        }
-        this->sent_cmd_ = 0;
-        this->read_pos_ = 0;
-        continue;
+  uint8_t buf[64];
+  while (avail > 0) {
+    size_t to_read = std::min(static_cast<size_t>(avail), sizeof(buf));
+    if (!this->read_array(buf, to_read)) {
+      break;
+    }
+    avail -= to_read;
+    for (size_t bi = 0; bi < to_read; bi++) {
+      uint8_t byte = buf[bi];
+
+      if (this->read_pos_ == DFPLAYER_READ_BUFFER_LENGTH)
+        this->read_pos_ = 0;
+
+      switch (this->read_pos_) {
+        case 0:  // Start mark
+          if (byte != 0x7E)
+            continue;
+          break;
+        case 1:  // Version
+          if (byte != 0xFF) {
+            ESP_LOGW(TAG, "Expected Version 0xFF, got %#02x", byte);
+            this->read_pos_ = 0;
+            continue;
+          }
+          break;
+        case 2:  // Buffer length
+          if (byte != 0x06) {
+            ESP_LOGW(TAG, "Expected Buffer length 0x06, got %#02x", byte);
+            this->read_pos_ = 0;
+            continue;
+          }
+          break;
+        case 9:  // End byte
+#ifdef ESPHOME_LOG_HAS_VERY_VERBOSE
+          char byte_sequence[100];
+          byte_sequence[0] = '\0';
+          for (size_t i = 0; i < this->read_pos_ + 1; ++i) {
+            snprintf(byte_sequence + strlen(byte_sequence), sizeof(byte_sequence) - strlen(byte_sequence), "%02X ",
+                     this->read_buffer_[i]);
+          }
+          ESP_LOGVV(TAG, "Received byte sequence: %s", byte_sequence);
+#endif
+          if (byte != 0xEF) {
+            ESP_LOGW(TAG, "Expected end byte 0xEF, got %#02x", byte);
+            this->read_pos_ = 0;
+            continue;
+          }
+          // Parse valid received command
+          uint8_t cmd = this->read_buffer_[3];
+          uint16_t argument = (this->read_buffer_[5] << 8) | this->read_buffer_[6];
+
+          ESP_LOGV(TAG, "Received message cmd: %#02x arg %#04x", cmd, argument);
+
+          switch (cmd) {
+            case 0x3A:
+              if (argument == 1) {
+                ESP_LOGI(TAG, "USB loaded");
+              } else if (argument == 2) {
+                ESP_LOGI(TAG, "TF Card loaded");
+              }
+              break;
+            case 0x3B:
+              if (argument == 1) {
+                ESP_LOGI(TAG, "USB unloaded");
+              } else if (argument == 2) {
+                ESP_LOGI(TAG, "TF Card unloaded");
+              }
+              break;
+            case 0x3F:
+              if (argument == 1) {
+                ESP_LOGI(TAG, "USB available");
+              } else if (argument == 2) {
+                ESP_LOGI(TAG, "TF Card available");
+              } else if (argument == 3) {
+                ESP_LOGI(TAG, "USB, TF Card available");
+              }
+              break;
+            case 0x40:
+              ESP_LOGV(TAG, "Nack");
+              this->ack_set_is_playing_ = false;
+              this->ack_reset_is_playing_ = false;
+              switch (argument) {
+                case 0x01:
+                  ESP_LOGE(TAG, "Module is busy or uninitialized");
+                  break;
+                case 0x02:
+                  ESP_LOGE(TAG, "Module is in sleep mode");
+                  break;
+                case 0x03:
+                  ESP_LOGE(TAG, "Serial receive error");
+                  break;
+                case 0x04:
+                  ESP_LOGE(TAG, "Checksum incorrect");
+                  break;
+                case 0x05:
+                  ESP_LOGE(TAG, "Specified track is out of current track scope");
+                  this->is_playing_ = false;
+                  break;
+                case 0x06:
+                  ESP_LOGE(TAG, "Specified track is not found");
+                  this->is_playing_ = false;
+                  break;
+                case 0x07:
+                  ESP_LOGE(TAG,
+                           "Insertion error (an inserting operation only can be done when a track is being played)");
+                  break;
+                case 0x08:
+                  ESP_LOGE(TAG, "SD card reading failed (SD card pulled out or damaged)");
+                  break;
+                case 0x09:
+                  ESP_LOGE(TAG, "Entered into sleep mode");
+                  this->is_playing_ = false;
+                  break;
+              }
+              break;
+            case 0x41:
+              ESP_LOGV(TAG, "Ack ok");
+              this->is_playing_ |= this->ack_set_is_playing_;
+              this->is_playing_ &= !this->ack_reset_is_playing_;
+              this->ack_set_is_playing_ = false;
+              this->ack_reset_is_playing_ = false;
+              break;
+            case 0x3C:
+              ESP_LOGV(TAG, "Playback finished (USB drive)");
+              this->is_playing_ = false;
+              this->on_finished_playback_callback_.call();
+            case 0x3D:
+              ESP_LOGV(TAG, "Playback finished (SD card)");
+              this->is_playing_ = false;
+              this->on_finished_playback_callback_.call();
+              break;
+            default:
+              ESP_LOGE(TAG, "Received unknown cmd %#02x arg %#04x", cmd, argument);
+          }
+          this->sent_cmd_ = 0;
+          this->read_pos_ = 0;
+          continue;
+      }
+      this->read_buffer_[this->read_pos_] = byte;
+      this->read_pos_++;
     }
-    this->read_buffer_[this->read_pos_] = byte;
-    this->read_pos_++;
   }
 }
 void DFPlayer::dump_config() {