libusb1_common, ftdi: clarify libusb_open error message

Print a user-friendly message when libusb_open() fails, e.g.
Error: libusb_open() failed with LIBUSB_ERROR_ACCESS
when there's a permissions problem.

Also output a configure warning if libusb older than 1.0.9 is detected.

Change-Id: I800f71f06672fe06c0a98a4e469f853b5021bcfe
Signed-off-by: Paul Fertser <fercerpav@gmail.com>
Reviewed-on: http://openocd.zylin.com/1430
Tested-by: jenkins
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>

configure.ac

@@ -1200,9 +1200,14 @@ use_libusb0=no
 use_libusb1=no
 if test $build_usb = yes -o $build_usb_ng = yes; then
   if test $check_libusb0 = no -a $build_usb_ng = yes; then
-	AC_CHECK_HEADER([libusb-1.0/libusb.h],
-			[AC_DEFINE(HAVE_LIBUSB1, 1, [Define if you have libusb-1.0]) check_libusb0=no use_libusb1=yes ],
-			[ check_libusb0=yes use_libusb1=no ])
+	AC_CHECK_HEADER([libusb-1.0/libusb.h], [
+	    AC_DEFINE(HAVE_LIBUSB1, 1, [Define if you have libusb-1.0])
+	    check_libusb0=no use_libusb1=yes
+	    AC_SEARCH_LIBS([libusb_error_name], [usb-1.0],
+	      [AC_DEFINE(HAVE_LIBUSB_ERROR_NAME, 1, [Define if your libusb has libusb_error_name()])],
+	      [AC_MSG_WARN([libusb-1 older than 1.0.9 detected, consider updating])])
+	  ], [
+	    check_libusb0=yes use_libusb1=no ])
   fi
 
   if test $check_libusb0 = yes -o $build_usb = yes; then

src/helper/replacements.c

@@ -276,3 +276,45 @@ int win_select(int max_fd, fd_set *rfds, fd_set *wfds, fd_set *efds, struct time
 	return retcode;
 }
 #endif
+
+#if defined HAVE_LIBUSB1 && !defined HAVE_LIBUSB_ERROR_NAME
+#include <libusb-1.0/libusb.h>
+/* Verbatim from git://git.libusb.org/libusb.git tag 1.0.9
+ * The libusb_error enum is compatible down to v0.9.1
+ */
+const char *libusb_error_name(int error_code)
+{
+	enum libusb_error error = error_code;
+	switch (error) {
+	case LIBUSB_SUCCESS:
+		return "LIBUSB_SUCCESS";
+	case LIBUSB_ERROR_IO:
+		return "LIBUSB_ERROR_IO";
+	case LIBUSB_ERROR_INVALID_PARAM:
+		return "LIBUSB_ERROR_INVALID_PARAM";
+	case LIBUSB_ERROR_ACCESS:
+		return "LIBUSB_ERROR_ACCESS";
+	case LIBUSB_ERROR_NO_DEVICE:
+		return "LIBUSB_ERROR_NO_DEVICE";
+	case LIBUSB_ERROR_NOT_FOUND:
+		return "LIBUSB_ERROR_NOT_FOUND";
+	case LIBUSB_ERROR_BUSY:
+		return "LIBUSB_ERROR_BUSY";
+	case LIBUSB_ERROR_TIMEOUT:
+		return "LIBUSB_ERROR_TIMEOUT";
+	case LIBUSB_ERROR_OVERFLOW:
+		return "LIBUSB_ERROR_OVERFLOW";
+	case LIBUSB_ERROR_PIPE:
+		return "LIBUSB_ERROR_PIPE";
+	case LIBUSB_ERROR_INTERRUPTED:
+		return "LIBUSB_ERROR_INTERRUPTED";
+	case LIBUSB_ERROR_NO_MEM:
+		return "LIBUSB_ERROR_NO_MEM";
+	case LIBUSB_ERROR_NOT_SUPPORTED:
+		return "LIBUSB_ERROR_NOT_SUPPORTED";
+	case LIBUSB_ERROR_OTHER:
+		return "LIBUSB_ERROR_OTHER";
+	}
+	return "**UNKNOWN**";
+}
+#endif

src/helper/replacements.h

@@ -279,4 +279,8 @@ typedef struct {
 
 #endif	/* HAVE_ELF_H */
 
+#if defined HAVE_LIBUSB1 && !defined HAVE_LIBUSB_ERROR_NAME
+const char *libusb_error_name(int error_code);
+#endif /* defined HAVE_LIBUSB1 && !defined HAVE_LIBUSB_ERROR_NAME */
+
 #endif	/* REPLACEMENTS_H */

src/jtag/drivers/libusb1_common.c

@@ -62,8 +62,11 @@ int jtag_libusb_open(const uint16_t vids[], const uint16_t pids[],
 		/** Free the device list **/
 		libusb_free_device_list(devs, 1);
 
-		if (errCode < 0)
+		if (errCode) {
+			LOG_ERROR("libusb_open() failed with %s",
+				  libusb_error_name(errCode));
 			return errCode;
+		}
 		return 0;
 	}
 	return -ENODEV;

src/jtag/drivers/mpsse.c

@@ -135,7 +135,8 @@ static bool open_matching_device(struct mpsse_ctx *ctx, const uint16_t *vid, con
 
 		err = libusb_open(device, &ctx->usb_dev);
 		if (err != LIBUSB_SUCCESS) {
-			LOG_ERROR("libusb_open() failed with %d", err);
+			LOG_ERROR("libusb_open() failed with %s",
+				  libusb_error_name(err));
 			continue;
 		}