serial: Support custom baud rates on linux

The function to do this is contained in custom_baud.c because
of broken include stuff.

Change-Id: I2a20f9182cb85e7bce5d6654a2caf20e6202b195
Signed-off-by: Urja Rannikko <urjaman@gmail.com>
Reviewed-on: https://review.coreboot.org/20224
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

1 files changed, 78 insertions, 0 deletions

diff --git a/custom_baud.c b/custom_baud.c
new file mode 100644
index 00000000..0caca80f
--- /dev/null
+++ b/custom_baud.c
@@ -0,0 +1,78 @@
+/*
+ * This file is part of the flashrom project.
+ *
+ * Copyright (C) 2017 Urja Rannikko <urjaman@gmail.com>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+ */
+
+#include "platform.h"
+#include "custom_baud.h"
+
+#if IS_LINUX
+#include <sys/ioctl.h>
+#include <fcntl.h>
+#include <asm-generic/termbits.h>
+#include <asm-generic/ioctls.h>
+
+/*
+ * This include hell above is why this is in a separate source file. See eg.
+ * https://www.downtowndougbrown.com/2013/11/linux-custom-serial-baud-rates/
+ * https://stackoverflow.com/questions/12646324/how-to-set-a-custom-baud-rate-on-linux
+ * https://github.com/jbkim/Linux-custom-baud-rate
+ * for more info.
+ */
+
+int set_custom_baudrate(int fd, unsigned int baud)
+{
+	struct termios2 tio;
+	if (ioctl(fd, TCGETS2, &tio)) {
+		return -1;
+	}
+	tio.c_cflag &= ~CBAUD;
+	tio.c_cflag |= BOTHER;
+	tio.c_ispeed = baud;
+	tio.c_ospeed = baud;
+	return ioctl(fd, TCSETS2, &tio);
+}
+
+int use_custom_baud(unsigned int baud, const struct baudentry *baudtable)
+{
+	int i;
+	for (i = 0; baudtable[i].baud; i++) {
+		if (baudtable[i].baud == baud)
+			return 0;
+
+		if (baudtable[i].baud > baud)
+			return 1;
+	}
+	return 1;
+}
+
+#else
+#include <errno.h>
+
+/* Stub, should not get called. */
+int set_custom_baudrate(int fd, unsigned int baud)
+{
+	errno = ENOSYS; /* Hoping "Function not supported" will make you look here. */
+	return -1;
+}
+
+int use_custom_baud(unsigned int baud, const struct baudentry *baudtable)
+{
+	return 0;
+}
+#endif