espnet: WIP support for on-chip WiFi on an ESP32C3

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "espnet/esp-idf"]
+	path = espnet/esp-idf
+	url = https://github.com/espressif/esp-idf.git

espnet/ap.go

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+package espnet
+
+/*
+#cgo CFLAGS: -DCONFIG_IDF_TARGET_ESP32C3
+#cgo CFLAGS: -Iinclude
+#cgo CFLAGS: -Iesp-idf/components/esp_common/include
+#cgo CFLAGS: -Iesp-idf/components/esp_event/include
+#cgo CFLAGS: -Iesp-idf/components/esp_netif/include
+#cgo CFLAGS: -Iesp-idf/components/esp_wifi/include
+
+#cgo LDFLAGS: -Lesp-idf/components/esp_wifi/lib/esp32c3 -lnet80211 -lpp -lphy -lmesh -lcore
+#cgo LDFLAGS: -Tesp-idf/components/esp_rom/esp32c3/ld/esp32c3.rom.ld
+
+#include "esp_private/wifi.h"
+#include "esp_wifi_types.h"
+#include "espnet.h"
+*/
+import "C"
+
+import _ "compat/freertos"
+
+type ESPWiFi struct {
+}
+
+var WiFi = &ESPWiFi{}
+
+type Config struct {
+}
+
+var internalConfig = C.wifi_init_config_t{
+	osi_funcs:           &C.g_wifi_osi_funcs,
+	wpa_crypto_funcs:    C.g_wifi_default_wpa_crypto_funcs,
+	static_rx_buf_num:   10,
+	static_tx_buf_num:   10,
+	mgmt_sbuf_num:       6,
+	sta_disconnected_pm: true,
+	magic:               C.WIFI_INIT_CONFIG_MAGIC,
+}
+
+func (wifi ESPWiFi) Configure(config Config) error {
+	C.esp_wifi_internal_set_log_level(5)
+	return makeError(C.esp_wifi_init_internal(&internalConfig))
+}
+
+func (wifi ESPWiFi) AccessPointMAC() ([6]byte, error) {
+	var mac [6]byte
+	errCode := C.esp_wifi_get_mac(C.ESP_IF_WIFI_AP, &mac[0])
+	return mac, makeError(errCode)
+}

espnet/error.go

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+package espnet
+
+// #include <esp_err.h>
+// #include <esp_wifi.h>
+import "C"
+
+// Wrapper for C.esp_err_t. Don't convert a C.esp_err_t to an Error type,
+// instead use makeError to handle ESP_OK.
+type Error C.esp_err_t
+
+// makeError converts a C.esp_err_t into an error or nil depending on whether
+// errCode indicates an error or not.
+func makeError(errCode C.esp_err_t) error {
+	if errCode == C.ESP_OK {
+		return nil
+	}
+	return Error(errCode)
+}
+
+func (e Error) Error() string {
+	switch {
+	case e < C.ESP_ERR_WIFI_BASE:
+		// esp-idf/components/esp_common/include/esp_err.h
+		switch e {
+		case C.ESP_OK:
+			return "OK" // not an error
+		case C.ESP_FAIL:
+			return "ESP FAIL"
+		case C.ESP_ERR_NO_MEM:
+			return "Out of memory"
+		case C.ESP_ERR_INVALID_ARG:
+			return "Invalid argument"
+		case C.ESP_ERR_INVALID_STATE:
+			return "Invalid state"
+		case C.ESP_ERR_INVALID_SIZE:
+			return "Invalid size"
+		case C.ESP_ERR_NOT_FOUND:
+			return "Requested resource not found"
+		case C.ESP_ERR_NOT_SUPPORTED:
+			return "Operation or feature not supported"
+		case C.ESP_ERR_TIMEOUT:
+			return "Operation timed out"
+		case C.ESP_ERR_INVALID_RESPONSE:
+			return "Received response was invalid"
+		case C.ESP_ERR_INVALID_CRC:
+			return "CRC or checksum was invalid"
+		case C.ESP_ERR_INVALID_VERSION:
+			return "Version was invalid"
+		case C.ESP_ERR_INVALID_MAC:
+			return "MAC address was invalid"
+		default:
+			return "Unknown error"
+		}
+	case e >= C.ESP_ERR_WIFI_BASE && e < C.ESP_ERR_MESH_BASE:
+		// esp-idf/components/esp_wifi/include/esp_wifi.h
+		switch e {
+		case C.ESP_ERR_WIFI_NOT_INIT:
+			return "WiFi driver was not installed by esp_wifi_init"
+		case C.ESP_ERR_WIFI_NOT_STARTED:
+			return "WiFi driver was not started by esp_wifi_start"
+		case C.ESP_ERR_WIFI_NOT_STOPPED:
+			return "WiFi driver was not stopped by esp_wifi_stop"
+		case C.ESP_ERR_WIFI_IF:
+			return "WiFi interface error"
+		case C.ESP_ERR_WIFI_MODE:
+			return "WiFi mode error"
+		case C.ESP_ERR_WIFI_STATE:
+			return "WiFi internal state error"
+		case C.ESP_ERR_WIFI_CONN:
+			return "WiFi internal control block of station or soft-AP error"
+		case C.ESP_ERR_WIFI_NVS:
+			return "WiFi internal NVS module error"
+		case C.ESP_ERR_WIFI_MAC:
+			return "MAC address is invalid"
+		case C.ESP_ERR_WIFI_SSID:
+			return " SSID is invalid"
+		case C.ESP_ERR_WIFI_PASSWORD:
+			return "Password is invalid"
+		case C.ESP_ERR_WIFI_TIMEOUT:
+			return "Timeout error"
+		case C.ESP_ERR_WIFI_WAKE_FAIL:
+			return "WiFi is in sleep state(RF closed) and wakeup fail"
+		case C.ESP_ERR_WIFI_WOULD_BLOCK:
+			return "The caller would block"
+		case C.ESP_ERR_WIFI_NOT_CONNECT:
+			return "Station still in disconnect status"
+		case C.ESP_ERR_WIFI_POST:
+			return "Failed to post the event to WiFi task"
+		case C.ESP_ERR_WIFI_INIT_STATE:
+			return "Invalid WiFi state when init/deinit is called"
+		case C.ESP_ERR_WIFI_STOP_STATE:
+			return "Returned when WiFi is stopping"
+		case C.ESP_ERR_WIFI_NOT_ASSOC:
+			return "The WiFi connection is not associated"
+		case C.ESP_ERR_WIFI_TX_DISALLOW:
+			return "The WiFi TX is disallowed"
+		default:
+			return "Other WiFi error"
+		}
+	default:
+		return "Other error"
+	}
+}