Initial PRU port for libgloss and newlib

Signed-off-by: Dimitar Dimitrov <dimitar@dinux.eu>

libgloss/pru/inbyte.c

@@ -0,0 +1,51 @@
+/* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
+ * inbyte.c -- inbyte function for remoteproc
+ *
+ * Copyright (c) 2018-2019 Dimitar Dimitrov <dimitar@dinux.eu>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+#include <errno.h>
+#include <_ansi.h>
+#include <stdio.h>
+#include <unistd.h>
+#include "glue.h"
+
+extern ssize_t _read(int fd, void *b, size_t count);
+
+int
+inbyte (void)
+{
+  ssize_t n;
+  char c;
+
+  /* PRU has no interrupts, so it is inherently thread-safe. */
+  n = _read(STDIN_FILENO, &c, 1);
+  if (n < 0)
+    return n;
+  else if (n == 0)
+    return -ENODATA;
+  else
+    return 1;
+}
+