Add ec_uartd build-side utility

This provides a pty for the EC UART channel on the BD-ICDI-B FTDI
daughtercard for EC debugging.

Signed-off-by: Randall Spangler <rspangler@chromium.org>

BUG=none
TEST=make && build/bds/util/ec_uartd (with EC attached to FTDI board)

Change-Id: I51fe50d0da6345962affb860b923425197a04fa1

1 files changed, 126 insertions, 0 deletions

diff --git a/util/ec_uartd.c b/util/ec_uartd.c
new file mode 100644
index 0000000000..ae2e51a580
--- /dev/null
+++ b/util/ec_uartd.c
@@ -0,0 +1,126 @@
+/* Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+/* ec_uartd.c - UART daemon for BD-ICDI-B board for EC debugging
+ *
+ * based on chromeos_public/src/third_party/hdctools/src/ftdiuart.c
+ *
+ * compile with:
+ *    gcc -o ftdi_uartd ftdi_uartd.c -lftdi
+ */
+
+/* Force header files to define grantpt(), posix_openpt(), cfmakeraw() */
+#define _BSD_SOURCE
+#define _XOPEN_SOURCE 600
+
+#include <fcntl.h>
+#include <ftdi.h>
+#include <getopt.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+#include <termios.h>
+#include <unistd.h>
+
+int main(int argc, char **argv)
+{
+	struct ftdi_context fcontext;
+	struct termios tty_cfg;
+	char ptname[PATH_MAX];
+	char buf[1024];
+	int fd;
+	int rv;
+
+	/* Init */
+	if (ftdi_init(&fcontext) < 0) {
+		fprintf(stderr, "ftdi_init failed\n");
+		return 1;
+	}
+
+	/* Open interface B (UART) in the FTDI device and set 115kbaud */
+	ftdi_set_interface(&fcontext, INTERFACE_B);
+	rv = ftdi_usb_open(&fcontext, 0x0403, 0xbcda);
+	if (rv < 0) {
+		fprintf(stderr, "error opening ftdi device: %d (%s)\n",
+			rv, ftdi_get_error_string(&fcontext));
+		return 2;
+	}
+	rv = ftdi_set_baudrate(&fcontext, 115200);
+	if (rv < 0) {
+		fprintf(stderr, "error setting baudrate: %d (%s)\n",
+			rv, ftdi_get_error_string(&fcontext));
+		return 2;
+	}
+
+	/* Set DTR; this muxes RX on the ICDI board */
+	ftdi_setdtr(&fcontext, 1);
+
+	/* Open the pty */
+	fd = posix_openpt(O_RDWR | O_NOCTTY);
+	if (fd == -1) {
+		perror("opening pty master");
+		return 3;
+	}
+	if (grantpt(fd) == -1) {
+		perror("grantpt");
+		return 3;
+	}
+	if (unlockpt(fd) == -1) {
+		perror("unlockpt");
+		return 3;
+	}
+	if (fcntl(fd, F_SETFL, O_NONBLOCK) == -1) {
+		perror("fcntl setfl -> nonblock");
+		return 3;
+	}
+	if (ptsname_r(fd, ptname, PATH_MAX) != 0) {
+		perror("getting name of pty");
+		return 3;
+	}
+	fprintf(stderr, "pty name = %s\n", ptname);
+	if (!isatty(fd)) {
+		perror("not a TTY device\n");
+		return 3;
+	}
+	cfmakeraw(&tty_cfg);
+	tcsetattr(fd, TCSANOW, &tty_cfg);
+	if (chmod(ptname, 0666) == -1) {
+		perror("setting pty attributes");
+		return 3;
+	}
+
+	/* Read and write data forever */
+	while (1) {
+		int bytes = read(fd, buf, sizeof(buf));
+		if (bytes > 0) {
+			rv = ftdi_write_data(&fcontext, buf, bytes);
+			if (rv != bytes) {
+				perror("writing to uart");
+				break;
+			}
+		}
+
+		usleep(1000);
+
+		bytes = ftdi_read_data(&fcontext, buf, sizeof(buf));
+		if (bytes > 0) {
+			int bytes_remaining = bytes;
+			while ((bytes = write(fd, buf, bytes_remaining)) > 0)
+				bytes_remaining -= bytes;
+
+			if (bytes == -1)
+				perror("writing ftdi data to pty");
+
+		} else if (bytes < 0) {
+			perror("failed ftdi_read_data");
+			break;
+		}
+	}
+
+	/* Cleanup */
+	close(fd);
+	ftdi_usb_close(&fcontext);
+	ftdi_deinit(&fcontext);
+	return 0;
+}