[sx126x] Optimize send_packet action memory usage - store static data in flash

esphome/components/sx126x/__init__.py

@@ -3,7 +3,7 @@ import esphome.codegen as cg
 from esphome.components import spi
 import esphome.config_validation as cv
 from esphome.const import CONF_BUSY_PIN, CONF_DATA, CONF_FREQUENCY, CONF_ID
-from esphome.core import TimePeriod
+from esphome.core import ID, TimePeriod
 
 MULTI_CONF = True
 CODEOWNERS = ["@swoboda1337"]
@@ -329,5 +329,8 @@ async def send_packet_action_to_code(config, action_id, template_arg, args):
         templ = await cg.templatable(data, args, cg.std_vector.template(cg.uint8))
         cg.add(var.set_data_template(templ))
     else:
-        cg.add(var.set_data_static(data))
+        # Generate static array in flash to avoid RAM copy
+        arr_id = ID(f"{action_id}_data", is_declaration=True, type=cg.uint8)
+        arr = cg.static_const_array(arr_id, cg.ArrayInitializer(*data))
+        cg.add(var.set_data_static(arr, len(data)))
     return var

esphome/components/sx126x/automation.h

@@ -14,28 +14,36 @@ template<typename... Ts> class RunImageCalAction : public Action<Ts...>, public
 
 template<typename... Ts> class SendPacketAction : public Action<Ts...>, public Parented<SX126x> {
  public:
-  void set_data_template(std::function<std::vector<uint8_t>(Ts...)> func) {
-    this->data_func_ = func;
+  void set_data_template(std::vector<uint8_t> (*func)(Ts...)) {
+    this->data_.func = func;
     this->static_ = false;
   }
 
-  void set_data_static(const std::vector<uint8_t> &data) {
-    this->data_static_ = data;
+  void set_data_static(const uint8_t *data, size_t len) {
+    this->data_.static_data.ptr = data;
+    this->data_.static_data.len = len;
     this->static_ = true;
   }
 
   void play(const Ts &...x) override {
+    std::vector<uint8_t> data;
     if (this->static_) {
-      this->parent_->transmit_packet(this->data_static_);
+      data.assign(this->data_.static_data.ptr, this->data_.static_data.ptr + this->data_.static_data.len);
     } else {
-      this->parent_->transmit_packet(this->data_func_(x...));
+      data = this->data_.func(x...);
     }
+    this->parent_->transmit_packet(data);
   }
 
  protected:
-  bool static_{false};
-  std::function<std::vector<uint8_t>(Ts...)> data_func_{};
-  std::vector<uint8_t> data_static_{};
+  bool static_{true};
+  union Data {
+    std::vector<uint8_t> (*func)(Ts...);
+    struct {
+      const uint8_t *ptr;
+      size_t len;
+    } static_data;
+  } data_;
 };
 
 template<typename... Ts> class SetModeTxAction : public Action<Ts...>, public Parented<SX126x> {

tests/components/sx126x/common.yaml

@@ -26,6 +26,15 @@ sx126x:
       - lambda: |-
           ESP_LOGD("lambda", "packet %.2f %.2f %s", rssi, snr, format_hex(x).c_str());
 
+number:
+  - platform: template
+    name: "SX126x Number"
+    id: my_number
+    optimistic: true
+    min_value: 0
+    max_value: 100
+    step: 1
+
 button:
   - platform: template
     name: "SX126x Button"
@@ -37,3 +46,5 @@ button:
         - sx126x.set_mode_rx
         - sx126x.send_packet:
             data: [0xC5, 0x51, 0x78, 0x82, 0xB7, 0xF9, 0x9C, 0x5C]
+        - sx126x.send_packet: !lambda |-
+            return {0x01, 0x02, (uint8_t)id(my_number).state};