Support L2CAP about esp32-nimble

[taks]

There are no immediate plan to support l2cap.
PR is welcome.

[taks]

I have implemented a simple feature of L2CAP.
Are there any additional functions required?

[milewski]

To be honest, I don't really understand how it works. I was trying to connect a Sony controller to an ESP32, and I found that it communicates via L2CAP. My first attempt was trying to use this library, but it didn't work.

Then, in the end, I found a reference code here in C (https://github.com/jvpernis/esp32-ps3/blob/master/src/ps3.c), and since it calls the ESP-IDF framework, I was able to translate the C code to unsafe Rust more or less one-to-one and get the controller working.

Certainly, it would have been much simpler and easier if I could have done all the integration directly with this library. Much of the initialization code was mostly copy/pasted from here:

esp32-nimble/src/ble_device.rs

Lines 54 to 87 in 1a12b5b

	if !INITIALIZED {
	let result = esp_idf_sys::nvs_flash_init();
	if result == esp_idf_sys::ESP_ERR_NVS_NO_FREE_PAGES
	|| result == esp_idf_sys::ESP_ERR_NVS_NEW_VERSION_FOUND
	{
	::log::warn!("NVS initialisation failed. Erasing NVS.");
	esp_nofail!(esp_idf_sys::nvs_flash_erase());
	esp_nofail!(esp_idf_sys::nvs_flash_init());
	}
	esp_idf_sys::esp_bt_controller_mem_release(
	esp_idf_sys::esp_bt_mode_t_ESP_BT_MODE_CLASSIC_BT,
	);
	#[cfg(esp_idf_version_major = "4")]
	esp_nofail!(esp_idf_sys::esp_nimble_hci_and_controller_init());
	esp_idf_sys::nimble_port_init();
	esp_idf_sys::ble_hs_cfg.sync_cb = Some(Self::on_sync);
	esp_idf_sys::ble_hs_cfg.reset_cb = Some(Self::on_reset);
	// Set initial security capabilities
	esp_idf_sys::ble_hs_cfg.sm_io_cap = esp_idf_sys::BLE_HS_IO_NO_INPUT_OUTPUT as _;
	esp_idf_sys::ble_hs_cfg.set_sm_bonding(0);
	esp_idf_sys::ble_hs_cfg.set_sm_mitm(0);
	esp_idf_sys::ble_hs_cfg.set_sm_sc(1);
	esp_idf_sys::ble_hs_cfg.sm_our_key_dist = 1;
	esp_idf_sys::ble_hs_cfg.sm_their_key_dist = 3;
	esp_idf_sys::ble_hs_cfg.store_status_cb = Some(esp_idf_sys::ble_store_util_status_rr);
	ble_store_config_init();
	esp_idf_sys::nimble_port_freertos_init(Some(Self::blecent_host_task));

[taks]

The ps3 controller does not seem to use BLE communication, but bluetooth classic communication.
Unfortunately, the nimble library is available for BLE only, so it cannot be used for communication with ps3 controllers.

[milewski]

Yeah, that was what I found as well. None of the newer ESP chips worked either because they don't support classic Bluetooth. Only an old ESP32 worked out.

I have ordered a ps5 controller which does support BLE, I found this: https://github.com/rodneybakiskan/ps5-esp32 once I get the controller I will try to port the classic code to the ble version and see how it goes.. l2cap still required

[taks]

The ps5 controller also seem to use bluetooth classic communication.
https://bluepad32.readthedocs.io/en/latest/supported_gamepads/#bluetooth-gamepads-and-their-protocol