[esp32] Place ring buffer functions in flash by default (prep for IDF 6.0)

esphome/components/esp32/__init__.py

@@ -592,6 +592,9 @@ CONF_LOOP_TASK_STACK_SIZE = "loop_task_stack_size"
 KEY_VFS_SELECT_REQUIRED = "vfs_select_required"
 KEY_VFS_DIR_REQUIRED = "vfs_dir_required"
 
+# Ring buffer IRAM requirement tracking
+KEY_RINGBUF_IN_IRAM = "ringbuf_in_iram"
+
 
 def require_vfs_select() -> None:
     """Mark that VFS select support is required by a component.
@@ -611,6 +614,17 @@ def require_vfs_dir() -> None:
     CORE.data[KEY_VFS_DIR_REQUIRED] = True
 
 
+def enable_ringbuf_in_iram() -> None:
+    """Keep ring buffer functions in IRAM instead of moving them to flash.
+
+    Call this from components that use esphome/core/ring_buffer.cpp and need
+    the ring buffer functions to remain in IRAM for performance reasons
+    (e.g., voice assistants, audio components).
+    This prevents CONFIG_RINGBUF_PLACE_FUNCTIONS_INTO_FLASH from being enabled.
+    """
+    CORE.data[KEY_RINGBUF_IN_IRAM] = True
+
+
 def _parse_idf_component(value: str) -> ConfigType:
     """Parse IDF component shorthand syntax like 'owner/component^version'"""
     if "^" not in value:
@@ -1021,6 +1035,18 @@ async def to_code(config):
         # IDF 6.0+: this is the default, option no longer exists
         add_idf_sdkconfig_option("CONFIG_FREERTOS_PLACE_FUNCTIONS_INTO_FLASH", True)
 
+    # Place ring buffer functions into flash instead of IRAM by default
+    # This saves IRAM but may impact performance for audio/voice components.
+    # Components that need ring buffer in IRAM call enable_ringbuf_in_iram().
+    # In ESP-IDF 6.0 flash placement becomes the default.
+    if CORE.data.get(KEY_RINGBUF_IN_IRAM, False):
+        # Component requires ring buffer in IRAM for performance
+        # IDF 6.0+: will need CONFIG_RINGBUF_PLACE_ISR_FUNCTIONS_INTO_FLASH=n
+        add_idf_sdkconfig_option("CONFIG_RINGBUF_PLACE_ISR_FUNCTIONS_INTO_FLASH", False)
+    else:
+        # No component needs it - place in flash to save IRAM
+        add_idf_sdkconfig_option("CONFIG_RINGBUF_PLACE_FUNCTIONS_INTO_FLASH", True)
+
     # Setup watchdog
     add_idf_sdkconfig_option("CONFIG_ESP_TASK_WDT", True)
     add_idf_sdkconfig_option("CONFIG_ESP_TASK_WDT_PANIC", True)

esphome/components/i2s_audio/__init__.py

@@ -1,6 +1,10 @@
 from esphome import pins
 import esphome.codegen as cg
-from esphome.components.esp32 import add_idf_sdkconfig_option, get_esp32_variant
+from esphome.components.esp32 import (
+    add_idf_sdkconfig_option,
+    enable_ringbuf_in_iram,
+    get_esp32_variant,
+)
 from esphome.components.esp32.const import (
     VARIANT_ESP32,
     VARIANT_ESP32C3,
@@ -274,6 +278,9 @@ async def to_code(config):
     # Helps avoid callbacks being skipped due to processor load
     add_idf_sdkconfig_option("CONFIG_I2S_ISR_IRAM_SAFE", True)
 
+    # Keep ring buffer functions in IRAM for audio performance
+    enable_ringbuf_in_iram()
+
     cg.add(var.set_lrclk_pin(config[CONF_I2S_LRCLK_PIN]))
     if CONF_I2S_BCLK_PIN in config:
         cg.add(var.set_bclk_pin(config[CONF_I2S_BCLK_PIN]))

esphome/components/micro_wake_word/__init__.py

@@ -448,6 +448,9 @@ async def to_code(config):
     # The inference task queues detection events that need immediate processing
     socket.require_wake_loop_threadsafe()
 
+    # Keep ring buffer functions in IRAM for audio performance
+    esp32.enable_ringbuf_in_iram()
+
     mic_source = await microphone.microphone_source_to_code(config[CONF_MICROPHONE])
     cg.add(var.set_microphone_source(mic_source))