uartat, le910: initial implementation.

uartat is the underlying UART driver, specifically for use with
AT-style command driven devices like modems.

The le910 support is provided in the form of examples that make use
of the uartat driver to interact with the device.

Signed-off-by: Jon Trulson <jtrulson@ics.com>

src/uartat/uartat_defs.h

@@ -0,0 +1,54 @@
+/*
+ * Author: Jon Trulson <jtrulson@ics.com>
+ * Copyright (c) 2017 Intel Corporation.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+    // possible flow control methods
+    typedef enum {
+        UARTAT_FLOW_CONTROL_NONE           = 0,
+        UARTAT_FLOW_CONTROL_HARD,          // hardware flow control
+        UARTAT_FLOW_CONTROL_SOFT           // software flow control
+    } UARTAT_FLOW_CONTROL_T;
+
+
+    // Numeric response codes via ITU-T V25Ter recommendations
+    typedef enum {
+        UARTAT_RESPONSE_CODE_OK            = 0,
+        UARTAT_RESPONSE_CODE_CONNECT       = 1,
+        UARTAT_RESPONSE_CODE_RING          = 2,
+        UARTAT_RESPONSE_CODE_NO_CARRIER    = 3,
+        UARTAT_RESPONSE_CODE_ERROR         = 4,
+        // 5 unassigned
+        UARTAT_RESPONSE_CODE_NO_DIALTONE   = 6,
+        UARTAT_RESPONSE_CODE_BUSY          = 7,
+        UARTAT_RESPONSE_CODE_NO_ANSWER     = 8
+    } UARTAT_RESPONSE_CODE_T;
+
+#ifdef __cplusplus
+}
+#endif