tools/usbwait/: new tool to wait for a USB device to appear

- usbwait/usbwait.c: update the USB device tree until the specified
  device is detected
- usbwait/Makefile: build usbwait (host only)
- Makefile (DIRS, BEN_DIRS, upload): separated subdirectories with tools
  that can run on the Ben from those that can't
- Makefile (DIRS): added usbwait/

tools/usbwait/usbwait.c

@@ -0,0 +1,102 @@
+/*
+ * usbwait/usbwait.c - Wait for a USB device to appear
+ *
+ * Written 2011 by Werner Almesberger
+ * Copyright 2011 Werner Almesberger
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/time.h>
+
+#include "usbopen.h"
+
+
+#define	DEFAULT_POLL_S	0.1
+
+
+static useconds_t interval_us = DEFAULT_POLL_S*1000000;
+static unsigned long timeout = 0;
+
+
+static void wait_for_usb(void)
+{
+	struct timeval to, now;
+
+	gettimeofday(&to, NULL);
+	to.tv_sec += timeout;
+
+	while (1) {
+		usb_rescan();
+		if (open_usb(0, 0))
+			return;
+		if (timeout) {
+			gettimeofday(&now, NULL);
+			if (now.tv_sec > to.tv_sec)
+				break;
+			if (now.tv_sec == to.tv_sec &&
+			    now.tv_usec > to.tv_usec)
+				break;
+		}
+		if (usleep(interval_us) < 0) {
+			perror("usleep");
+			exit(1);
+		}
+	}
+
+	fprintf(stderr, "timeout\n");
+	exit(1);
+}
+
+
+static void usage(const char *name)
+{
+	fprintf(stderr,
+"usage: %s [-i poll_s] [-p path] [-t timeout_s] [vendor]:[product]\n\n"
+"  -i poll_s     poll interval in seconds (default: %g s)\n"
+"  -p path       USB device path\n"
+"  -t timeout_s  timeout in seconds (default: infinite)\n"
+  , name, DEFAULT_POLL_S);
+	exit(1);
+}
+
+
+int main(int argc, char **argv)
+{
+	char *end;
+	int c;
+
+	while ((c = getopt(argc, argv, "i:p:t:")) != EOF)
+		switch (c) {
+		case 'i':
+			interval_us = strtod(optarg, &end)*1000000;
+			if (*end || interval_us < 0)
+				usage(*argv);
+			break;
+		case 'p':
+			restrict_usb_path(optarg);
+			break;
+		case 't':
+			timeout = strtoul(optarg, &end, 0);
+			if (*end || !timeout)
+				usage(*argv);
+			break;
+		default:
+			usage(*argv);
+		}
+
+	if (argc != optind+1)
+		usage(*argv);
+
+	parse_usb_id(argv[optind]);
+	wait_for_usb();
+
+	return 0;
+}