espradio: implement support for wifi/BLE on the ESP32-C3

This is a work in progress. It does not yet work.

espradio/error.go

@@ -0,0 +1,44 @@
+package espradio
+
+/*
+#include "include.h"
+*/
+import "C"
+
+// Error is an error from the radio stack.
+type Error C.esp_err_t
+
+func (e Error) Error() string {
+	switch {
+	case e >= C.ESP_ERR_MEMPROT_BASE:
+		return "espradio: unknown memprot error"
+	case e >= C.ESP_ERR_HW_CRYPTO_BASE:
+		return "espradio: unknown hw crypto error"
+	case e >= C.ESP_ERR_FLASH_BASE:
+		return "espradio: unknown flash error"
+	case e >= C.ESP_ERR_MESH_BASE:
+		return "espradio: unknown mesh error"
+	case e >= C.ESP_ERR_WIFI_BASE:
+		return "espradio: unknown wifi error"
+	default:
+		switch e {
+		case C.ESP_OK:
+			return "espradio: no error" // invalid usage of the Error type
+		case C.ESP_ERR_NO_MEM:
+			return "espradio: no memory"
+		case C.ESP_ERR_INVALID_ARG:
+			return "espradio: invalid argument"
+		default:
+			return "espradio: unknown error"
+		}
+	}
+}
+
+// makeError returns an error (using the Error type) if the error code is
+// non-zero, otherwise it returns nil.
+func makeError(errCode C.esp_err_t) error {
+	if errCode != 0 {
+		return Error(errCode)
+	}
+	return nil
+}