serial: More error-checking & logging, add baudrates.

This mostly affects the non-Windows code so far, the rest will follow.

hardware/common/serial.c

@@ -2,6 +2,7 @@
  * This file is part of the sigrok project.
  *
  * Copyright (C) 2010-2012 Bert Vermeulen <bert@biot.com>
+ * Copyright (C) 2010-2012 Uwe Hermann <uwe@hermann-uwe.de>
  *
  * 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
@@ -29,10 +30,20 @@
 #include <termios.h>
 #endif
 #include <stdlib.h>
+#include <errno.h>
 #include <glib.h>
 #include "libsigrok.h"
 #include "libsigrok-internal.h"
 
+/* Message logging helpers with driver-specific prefix string. */
+#define DRIVER_LOG_DOMAIN "serial: "
+#define sr_log(l, s, args...) sr_log(l, DRIVER_LOG_DOMAIN s, ## args)
+#define sr_spew(s, args...) sr_spew(DRIVER_LOG_DOMAIN s, ## args)
+#define sr_dbg(s, args...) sr_dbg(DRIVER_LOG_DOMAIN s, ## args)
+#define sr_info(s, args...) sr_info(DRIVER_LOG_DOMAIN s, ## args)
+#define sr_warn(s, args...) sr_warn(DRIVER_LOG_DOMAIN s, ## args)
+#define sr_err(s, args...) sr_err(DRIVER_LOG_DOMAIN s, ## args)
+
 // FIXME: Must be moved, or rather passed as function argument.
 #ifdef _WIN32
 static HANDLE hdl;
@@ -54,6 +65,8 @@ SR_PRIV GSList *list_serial_ports(void)
 {
 	GSList *ports;
 
+	sr_dbg("Getting list of serial ports on the system.");
+
 #ifdef _WIN32
 	/* TODO */
 	ports = NULL;
@@ -66,8 +79,10 @@ SR_PRIV GSList *list_serial_ports(void)
 	for (i = 0; serial_port_glob[i]; i++) {
 		if (glob(serial_port_glob[i], 0, NULL, &g))
 			continue;
-		for (j = 0; j < g.gl_pathc; j++)
+		for (j = 0; j < g.gl_pathc; j++) {
 			ports = g_slist_append(ports, g_strdup(g.gl_pathv[j]));
+			sr_dbg("Found serial port '%s'.", g.gl_pathv[j]);
+		}
 		globfree(&g);
 	}
 #endif
@@ -75,57 +90,113 @@ SR_PRIV GSList *list_serial_ports(void)
 	return ports;
 }
 
+/**
+ * Open the specified serial port.
+ *
+ * @param pathname OS-specific serial port specification. Examples:
+ *                 "/dev/ttyUSB0", "/dev/ttyACM1", "/dev/tty.Modem-0", "COM1".
+ * @param flags Flags to use when opening the serial port.
+ *
+ * @return 0 upon success, -1 upon failure.
+ */
 SR_PRIV int serial_open(const char *pathname, int flags)
 {
+	/* TODO: Abstract 'flags', currently they're OS-specific! */
+
+	sr_dbg("Opening serial port '%s' (flags = %d).", pathname, flags);
+
 #ifdef _WIN32
-	/* FIXME: Don't hardcode COM1. */
+	pathname = "COM1"; /* FIXME: Don't hardcode COM1. */
-	hdl = CreateFile("COM1", GENERIC_READ | GENERIC_WRITE, 0, 0,
+
+	hdl = CreateFile(pathname, GENERIC_READ | GENERIC_WRITE, 0, 0,
 			 OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);
 	if (hdl == INVALID_HANDLE_VALUE) {
-		/* TODO: Error handling. */
+		sr_err("Error opening serial port '%s'.", pathname);
+		return -1;
 	}
 	return 0;
 #else
-	return open(pathname, flags);
+	int fd;
+
+	if ((fd = open(pathname, flags)) < 0) {
+		/*
+		 * Should be sr_err(), but since some drivers try to open all
+		 * ports on a system and see if they succeed, this would
+		 * yield ugly output for e.g. "sigrok-cli -D".
+		 */
+		sr_dbg("Error opening serial port '%s': %s.", pathname,
+		       strerror(errno));
+	}
+
+	return fd;
 #endif
 }
 
-/*
+/**
- * Close the serial port.
+ * Close the specified serial port.
- * Returns 0 upon success, -1 upon failure.
+ *
+ * @param fd File descriptor of the serial port.
+ *
+ * @return 0 upon success, -1 upon failure.
  */
 SR_PRIV int serial_close(int fd)
 {
+	sr_dbg("FD %d: Closing serial port.", fd);
+
 #ifdef _WIN32
 	/* Returns non-zero upon success, 0 upon failure. */
 	return (CloseHandle(hdl) == 0) ? -1 : 0;
 #else
+	int ret;
+
 	/* Returns 0 upon success, -1 upon failure. */
-	return close(fd);
+	if ((ret = close(fd)) < 0) {
+		sr_dbg("FD %d: Error closing serial port: %s.",
+		       fd, strerror(errno));
+	}
+
+	return ret;
 #endif
 }
 
-/*
+/**
  * Flush serial port buffers (if any).
- * Returns 0 upon success, -1 upon failure.
+ *
+ * @param fd File descriptor of the serial port.
+ *
+ * @return 0 upon success, -1 upon failure.
  */
 SR_PRIV int serial_flush(int fd)
 {
+	sr_dbg("FD %d: Flushing serial port.", fd);
+
 #ifdef _WIN32
 	/* Returns non-zero upon success, 0 upon failure. */
 	return (PurgeComm(hdl, PURGE_RXCLEAR | PURGE_TXCLEAR) == 0) ? -1 : 0;
 #else
+	int ret;
+
 	/* Returns 0 upon success, -1 upon failure. */
-	return tcflush(fd, TCIOFLUSH);
+	if ((ret = tcflush(fd, TCIOFLUSH)) < 0)
+		sr_err("Error flushing serial port: %s.", strerror(errno));
+
+	return ret;
 #endif
 }
 
-/*
+/**
  * Write a number of bytes to the specified serial port.
- * Returns the number of bytes written, or -1 upon failure.
+ *
+ * @param fd File descriptor of the serial port.
+ * @param buf Buffer containing the bytes to write.
+ * @param count Number of bytes to write.
+ *
+ * @return The number of bytes written, or -1 upon failure.
  */
 SR_PRIV int serial_write(int fd, const void *buf, size_t count)
 {
+	sr_spew("FD %d: Writing %d bytes.", fd, count);
+
 #ifdef _WIN32
 	DWORD tmp = 0;
 
@@ -133,17 +204,32 @@ SR_PRIV int serial_write(int fd, const void *buf, size_t count)
 	/* Returns non-zero upon success, 0 upon failure. */
 	WriteFile(hdl, buf, count, &tmp, NULL);
 #else
+	ssize_t ret;
+
 	/* Returns the number of bytes written, or -1 upon failure. */
-	return write(fd, buf, count);
+	ret = write(fd, buf, count);
+	if (ret < 0)
+		sr_err("FD %d: Write error: %s.", fd, strerror(errno));
+	else if ((size_t)ret != count)
+		sr_spew("FD %d: Only wrote %d/%d bytes.", fd, ret, count);
+
+	return ret;
 #endif
 }
 
-/*
+/**
  * Read a number of bytes from the specified serial port.
- * Returns the number of bytes read, or -1 upon failure.
+ *
+ * @param fd File descriptor of the serial port.
+ * @param buf Buffer where to store the bytes that are read.
+ * @param count The number of bytes to read.
+ *
+ * @return The number of bytes read, or -1 upon failure.
  */
 SR_PRIV int serial_read(int fd, void *buf, size_t count)
 {
+	sr_spew("FD %d: Reading %d bytes.", fd, count);
+
 #ifdef _WIN32
 	DWORD tmp = 0;
 
@@ -151,48 +237,104 @@ SR_PRIV int serial_read(int fd, void *buf, size_t count)
 	/* Returns non-zero upon success, 0 upon failure. */
 	return ReadFile(hdl, buf, count, &tmp, NULL);
 #else
+	ssize_t ret;
+
 	/* Returns the number of bytes read, or -1 upon failure. */
-	return read(fd, buf, count);
+	ret = read(fd, buf, count);
+	if (ret < 0) {
+		/*
+ 		 * Should be sr_err(), but that would yield lots of
+		 * "Resource temporarily unavailable" messages.
+		 */
+		sr_spew("FD %d: Read error: %s.", fd, strerror(errno));
+	} else if ((size_t)ret != count) {
+		sr_spew("FD %d: Only read %d/%d bytes.", fd, ret, count);
+	}
+
+	return ret;
 #endif
 }
 
+/**
+ * Create a backup of the current parameters of the specified serial port.
+ *
+ * @param fd File descriptor of the serial port.
+ *
+ * @return Pointer to a struct termios upon success, NULL upon errors.
+ *         It is the caller's responsibility to g_free() the pointer if no
+ *         longer needed.
+ */
 SR_PRIV void *serial_backup_params(int fd)
 {
+	sr_dbg("FD %d: Creating serial parameters backup.", fd);
+
 #ifdef _WIN32
 	/* TODO */
 #else
 	struct termios *term;
 
-	/* TODO: 'term' is never g_free()'d? */
 	if (!(term = g_try_malloc(sizeof(struct termios)))) {
-		sr_err("serial: %s: term malloc failed", __func__);
+		sr_err("termios struct malloc failed.");
-		return -1;
+		return NULL;
 	}
 
-	tcgetattr(fd, term);
+	/* Returns 0 upon success, -1 upon failure. */
+	if (tcgetattr(fd, term) < 0) {
+		sr_err("FD %d: Error getting serial parameters: %s.",
+		       strerror(errno));
+		g_free(term);
+		return NULL;
+	}
 
 	return term;
 #endif
 }
 
-SR_PRIV void serial_restore_params(int fd, void *backup)
+/**
+ * Restore serial port settings from a previously created backup.
+ *
+ * @param fd File descriptor of the serial port.
+ * @param backup Pointer to a struct termios which contains the settings
+ *               to restore.
+ *
+ * @return 0 upon success, -1 upon failure.
+ */
+SR_PRIV int serial_restore_params(int fd, void *backup)
 {
+	sr_dbg("FD %d: Restoring serial parameters from backup.", fd);
+
 #ifdef _WIN32
 	/* TODO */
 #else
-	tcsetattr(fd, TCSADRAIN, (struct termios *)backup);
+	int ret;
+
+	/* Returns 0 upon success, -1 upon failure. */
+	if ((ret = tcsetattr(fd, TCSADRAIN, (struct termios *)backup)) < 0) {
+		sr_err("FD %d: Error restoring serial parameters: %s.",
+		       strerror(errno));
+	}
+
+	return ret;
 #endif
 }
 
-/*
+/**
- * Set serial parameters.
+ * Set serial parameters for the specified serial port.
  *
- * flowcontrol: 1 = rts/cts, 2 = xon/xoff
+ * @param baudrate The baudrate to set.
- * parity: 0 = none, 1 = even, 2 = odd
+ * @param bits The number of data bits to use.
+ * @param parity The parity setting to use (0 = none, 1 = even, 2 = odd).
+ * @param stopbits The number of stop bits to use (1 or 2).
+ * @param flowcontrol The flow control settings to use (0 = none, 1 = RTS/CTS,
+ *                    2 = XON/XOFF).
+ *
+ * @return SR_OK upon success, SR_ERR upon failure.
  */
 SR_PRIV int serial_set_params(int fd, int baudrate, int bits, int parity,
 			      int stopbits, int flowcontrol)
 {
+	sr_dbg("FD %d: Setting serial parameters.", fd);
+
 #ifdef _WIN32
 	DCB dcb;
 
@@ -225,8 +367,8 @@ SR_PRIV int serial_set_params(int fd, int baudrate, int bits, int parity,
 		dcb.BaudRate = CBR_2400;
 		break;
 	default:
-		/* TODO: Error handling. */
+		sr_err("Unsupported baudrate: %d.", baudrate);
-		break;
+		return SR_ERR;
 	}
 	dcb.ByteSize = bits;
 	dcb.Parity = NOPARITY; /* TODO: Don't hardcode. */
@@ -240,10 +382,43 @@ SR_PRIV int serial_set_params(int fd, int baudrate, int bits, int parity,
 	struct termios term;
 	speed_t baud;
 
-	if (tcgetattr(fd, &term) < 0)
+	sr_dbg("FD %d: Getting terminal settings.", fd);
+	if (tcgetattr(fd, &term) < 0) {
+		sr_err("tcgetattr() error: %ѕ.", strerror(errno));
 		return SR_ERR;
+	}
 
 	switch (baudrate) {
+	case 50:
+		baud = B50;
+		break;
+	case 75:
+		baud = B75;
+		break;
+	case 110:
+		baud = B110;
+		break;
+	case 134:
+		baud = B134;
+		break;
+	case 150:
+		baud = B150;
+		break;
+	case 200:
+		baud = B200;
+		break;
+	case 300:
+		baud = B300;
+		break;
+	case 600:
+		baud = B600;
+		break;
+	case 1200:
+		baud = B1200;
+		break;
+	case 1800:
+		baud = B1800;
+		break;
 	case 2400:
 		baud = B2400;
 		break;
@@ -253,6 +428,9 @@ SR_PRIV int serial_set_params(int fd, int baudrate, int bits, int parity,
 	case 9600:
 		baud = B9600;
 		break;
+	case 19200:
+		baud = B19200;
+		break;
 	case 38400:
 		baud = B38400;
 		break;
@@ -262,19 +440,34 @@ SR_PRIV int serial_set_params(int fd, int baudrate, int bits, int parity,
 	case 115200:
 		baud = B115200;
 		break;
+	case 230400:
+		baud = B230400;
+		break;
 #ifndef __APPLE__
 	case 460800:
 		baud = B460800;
 		break;
 #endif
 	default:
+		sr_err("Unsupported baudrate: %d.", baudrate);
 		return SR_ERR;
 	}
-	if (cfsetospeed(&term, baud) < 0)
-		return SR_ERR;
-	if (cfsetispeed(&term, baud) < 0)
-		return SR_ERR;
 
+	sr_dbg("FD %d: Configuring output baudrate to %d (%d).",
+		fd, baudrate, baud);
+	if (cfsetospeed(&term, baud) < 0) {
+		sr_err("cfsetospeed() error: %ѕ.", strerror(errno));
+		return SR_ERR;
+	}
+
+	sr_dbg("FD %d: Configuring input baudrate to %d (%d).",
+		fd, baudrate, baud);
+	if (cfsetispeed(&term, baud) < 0) {
+		sr_err("cfsetispeed() error: %ѕ.", strerror(errno));
+		return SR_ERR;
+	}
+
+	sr_dbg("FD %d: Configuring %d data bits.", fd, bits);
 	term.c_cflag &= ~CSIZE;
 	switch (bits) {
 	case 8:
@@ -284,17 +477,21 @@ SR_PRIV int serial_set_params(int fd, int baudrate, int bits, int parity,
 		term.c_cflag |= CS7;
 		break;
 	default:
+		sr_err("Unsupported data bits number: %d.", bits);
 		return SR_ERR;
 	}
 
+	sr_dbg("FD %d: Configuring %d stop bits.", fd, stopbits);
 	term.c_cflag &= ~CSTOPB;
 	switch (stopbits) {
 	case 1:
+		/* Do nothing, a cleared CSTOPB entry means "1 stop bit". */
 		break;
 	case 2:
 		term.c_cflag |= CSTOPB;
 		break;
 	default:
+		sr_err("Unsupported stopbits number: %d.", stopbits);
 		return SR_ERR;
 	}
 
@@ -303,14 +500,18 @@ SR_PRIV int serial_set_params(int fd, int baudrate, int bits, int parity,
 	switch (flowcontrol) {
 	case 0:
 		/* No flow control. */
+		sr_dbg("FD %d: Configuring no flow control.", fd);
 		break;
 	case 1:
+		sr_dbg("FD %d: Configuring RTS/CTS flow control.", fd);
 		term.c_cflag |= CRTSCTS;
 		break;
 	case 2:
+		sr_dbg("FD %d: Configuring XON/XOFF flow control.", fd);
 		term.c_iflag |= IXON | IXOFF;
 		break;
 	default:
+		sr_err("Unsupported flow control setting: %d.", flowcontrol);
 		return SR_ERR;
 	}
 
@@ -318,24 +519,33 @@ SR_PRIV int serial_set_params(int fd, int baudrate, int bits, int parity,
 	term.c_cflag &= ~(PARODD | PARENB);
 	switch (parity) {
 	case SERIAL_PARITY_NONE:
+		sr_dbg("FD %d: Configuring no parity.", fd);
 		term.c_iflag |= IGNPAR;
 		break;
 	case SERIAL_PARITY_EVEN:
+		sr_dbg("FD %d: Configuring even parity.", fd);
 		term.c_cflag |= PARENB;
 		break;
 	case SERIAL_PARITY_ODD:
+		sr_dbg("FD %d: Configuring odd parity.", fd);
 		term.c_cflag |= PARENB | PARODD;
 		break;
 	default:
+		sr_err("Unsupported parity setting: %d.", parity);
 		return SR_ERR;
 	}
 
-	/* Some default parameters */
+	/* Do NOT translate carriage return to newline on input. */
 	term.c_iflag &= ~(ICRNL);
+
+	/* Disable canonical mode, and don't echo input characters. */
 	term.c_lflag &= ~(ICANON | ECHO);
 
-	if (tcsetattr(fd, TCSADRAIN, &term) < 0)
+	/* Write the configured settings. */
+	if (tcsetattr(fd, TCSADRAIN, &term) < 0) {
+		sr_err("tcsetattr() error: %ѕ.", strerror(errno));
 		return SR_ERR;
+	}
 #endif
 
 	return SR_OK;

libsigrok-internal.h

@@ -131,7 +131,7 @@ SR_PRIV int serial_flush(int fd);
 SR_PRIV int serial_write(int fd, const void *buf, size_t count);
 SR_PRIV int serial_read(int fd, void *buf, size_t count);
 SR_PRIV void *serial_backup_params(int fd);
-SR_PRIV void serial_restore_params(int fd, void *backup);
+SR_PRIV int serial_restore_params(int fd, void *backup);
 SR_PRIV int serial_set_params(int fd, int baudrate, int bits, int parity,
 			      int stopbits, int flowcontrol);
 SR_PRIV int serial_set_paramstr(int fd, const char *paramstr);