X-Git-Url: https://sigrok.org/gitweb/?a=blobdiff_plain;f=hardware%2Fcommon%2Fserial.c;h=a18ad0b494073962f1bc7fb182b4e1c95db3b2e3;hb=93357bc3ce484c2e46a9999d4464ce2d5cc976b6;hp=239c718125a911fb8f74d9e2e8820f0f7d987ec0;hpb=a99e0d2a0c9d1bb4db5623ba50f83486238ee793;p=libsigrok.git diff --git a/hardware/common/serial.c b/hardware/common/serial.c index 239c7181..a18ad0b4 100644 --- a/hardware/common/serial.c +++ b/hardware/common/serial.c @@ -3,6 +3,7 @@ * * Copyright (C) 2010-2012 Bert Vermeulen * Copyright (C) 2010-2012 Uwe Hermann + * Copyright (C) 2012 Alexandru Gagniuc * * 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 @@ -28,6 +29,7 @@ #else #include #include +#include #endif #include #include @@ -52,94 +54,148 @@ static HANDLE hdl; /** * 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. + * @param serial Previously initialized serial port structure. + * @param flags Flags to use when opening the serial port. Possible flags + * include SERIAL_RDWR, SERIAL_RDONLY, SERIAL_NONBLOCK. * - * @return 0 upon success, -1 upon failure. + * If the serial structure contains a serialcomm string, it will be + * passed to serial_set_paramstr() after the port is opened. + * + * @return SR_OK on success, SR_ERR on failure. */ -SR_PRIV int serial_open(const char *pathname, int flags) +SR_PRIV int serial_open(struct sr_serial_dev_inst *serial, int flags) { - /* TODO: Abstract 'flags', currently they're OS-specific! */ + int flags_local = 0; +#ifdef _WIN32 + DWORD desired_access = 0, flags_and_attributes = 0; +#endif - sr_dbg("Opening serial port '%s' (flags = %d).", pathname, flags); + if (!serial) { + sr_dbg("Invalid serial port."); + return SR_ERR; + } -#ifdef _WIN32 - pathname = "COM1"; /* FIXME: Don't hardcode COM1. */ + sr_spew("Opening serial port '%s' (flags %d).", serial->port, flags); - hdl = CreateFile(pathname, GENERIC_READ | GENERIC_WRITE, 0, 0, - OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0); +#ifdef _WIN32 + /* Map 'flags' to the OS-specific settings. */ + desired_access |= GENERIC_READ; + flags_and_attributes = FILE_ATTRIBUTE_NORMAL; + if (flags & SERIAL_RDWR) + desired_access |= GENERIC_WRITE; + if (flags & SERIAL_NONBLOCK) + flags_and_attributes |= FILE_FLAG_OVERLAPPED; + + hdl = CreateFile(serial->port, desired_access, 0, 0, + OPEN_EXISTING, flags_and_attributes, 0); if (hdl == INVALID_HANDLE_VALUE) { - sr_err("Error opening serial port '%s'.", pathname); - return -1; + sr_err("Error opening serial port '%s'.", serial->port); + return SR_ERR; } - return 0; #else - 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, + /* Map 'flags' to the OS-specific settings. */ + if (flags & SERIAL_RDWR) + flags_local |= O_RDWR; + if (flags & SERIAL_RDONLY) + flags_local |= O_RDONLY; + if (flags & SERIAL_NONBLOCK) + flags_local |= O_NONBLOCK; + + if ((serial->fd = open(serial->port, flags_local)) < 0) { + sr_err("Error opening serial port '%s': %s.", serial->port, strerror(errno)); - } else { - sr_dbg("Opened serial port '%s' as FD %d.", pathname, fd); + return SR_ERR; } - return fd; + sr_spew("Opened serial port '%s' (fd %d).", serial->port, serial->fd); #endif + + if (serial->serialcomm) + return serial_set_paramstr(serial, serial->serialcomm); + else + return SR_OK; } /** * Close the specified serial port. * - * @param fd File descriptor of the serial port. + * @param serial Previously initialized serial port structure. * - * @return 0 upon success, -1 upon failure. + * @return SR_OK on success, SR_ERR on failure. */ -SR_PRIV int serial_close(int fd) +SR_PRIV int serial_close(struct sr_serial_dev_inst *serial) { - sr_dbg("FD %d: Closing serial port.", fd); + int ret; + + if (!serial) { + sr_dbg("Invalid serial port."); + return SR_ERR; + } + + if (serial->fd == -1) { + sr_dbg("Cannot close unopened serial port %s (fd %d).", + serial->port, serial->fd); + return SR_ERR; + } + + sr_spew("Closing serial port %s (fd %d).", serial->port, serial->fd); + ret = SR_OK; #ifdef _WIN32 /* Returns non-zero upon success, 0 upon failure. */ - return (CloseHandle(hdl) == 0) ? -1 : 0; + if (CloseHandle(hdl) == 0) + ret = SR_ERR; #else - int ret; - /* Returns 0 upon success, -1 upon failure. */ - if ((ret = close(fd)) < 0) { - sr_dbg("FD %d: Error closing serial port: %s.", - fd, strerror(errno)); + if (close(serial->fd) < 0) { + sr_err("Error closing serial port: %s (fd %d).", strerror(errno), + serial->fd); + ret = SR_ERR; } +#endif + + serial->fd = -1; return ret; -#endif } /** - * Flush serial port buffers (if any). + * Flush serial port buffers. * - * @param fd File descriptor of the serial port. + * @param serial Previously initialized serial port structure. * - * @return 0 upon success, -1 upon failure. + * @return SR_OK on success, SR_ERR on failure. */ -SR_PRIV int serial_flush(int fd) +SR_PRIV int serial_flush(struct sr_serial_dev_inst *serial) { - sr_dbg("FD %d: Flushing serial port.", fd); + int ret; + + if (!serial) { + sr_dbg("Invalid serial port."); + return SR_ERR; + } + + if (serial->fd == -1) { + sr_dbg("Cannot flush unopened serial port %s (fd %d).", + serial->port, serial->fd); + return SR_ERR; + } + + sr_spew("Flushing serial port %s (fd %d).", serial->port, serial->fd); + ret = SR_OK; #ifdef _WIN32 /* Returns non-zero upon success, 0 upon failure. */ - return (PurgeComm(hdl, PURGE_RXCLEAR | PURGE_TXCLEAR) == 0) ? -1 : 0; + if (PurgeComm(hdl, PURGE_RXCLEAR | PURGE_TXCLEAR) == 0) { + sr_err("Error flushing serial port: %s.", strerror(errno)); + ret = SR_ERR; + } #else - int ret; - /* Returns 0 upon success, -1 upon failure. */ - if ((ret = tcflush(fd, TCIOFLUSH)) < 0) + if (tcflush(serial->fd, TCIOFLUSH) < 0) { sr_err("Error flushing serial port: %s.", strerror(errno)); + ret = SR_ERR; + } return ret; #endif @@ -148,14 +204,28 @@ SR_PRIV int serial_flush(int fd) /** * Write a number of bytes to the specified serial port. * - * @param fd File descriptor of the serial port. + * @param serial Previously initialized serial port structure. * @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_PRIV int serial_write(struct sr_serial_dev_inst *serial, + const void *buf, size_t count) { + ssize_t ret; + + if (!serial) { + sr_dbg("Invalid serial port."); + return -1; + } + + if (serial->fd == -1) { + sr_dbg("Cannot use unopened serial port %s (fd %d).", + serial->port, serial->fd); + return -1; + } + #ifdef _WIN32 DWORD tmp = 0; @@ -163,30 +233,42 @@ 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. */ - ret = write(fd, buf, count); + ret = write(serial->fd, buf, count); if (ret < 0) - sr_err("FD %d: Write error: %s.", fd, strerror(errno)); + sr_err("Write error: %s.", strerror(errno)); else - sr_spew("FD %d: Wrote %d/%d bytes.", fd, ret, count); + sr_spew("Wrote %d/%d bytes (fd %d).", ret, count, serial->fd); +#endif return ret; -#endif } /** * Read a number of bytes from the specified serial port. * - * @param fd File descriptor of the serial port. + * @param serial Previously initialized serial port structure. * @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_PRIV int serial_read(struct sr_serial_dev_inst *serial, void *buf, + size_t count) { + ssize_t ret; + + if (!serial) { + sr_dbg("Invalid serial port."); + return -1; + } + + if (serial->fd == -1) { + sr_dbg("Cannot use unopened serial port %s (fd %d).", + serial->port, serial->fd); + return -1; + } + #ifdef _WIN32 DWORD tmp = 0; @@ -194,27 +276,25 @@ 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. */ - ret = read(fd, buf, count); - if (ret < 0) { + ret = read(serial->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 { - sr_spew("FD %d: Read %d/%d bytes.", fd, ret, count); - } + sr_spew("Read error: %s (fd %d).", strerror(errno), serial->fd); + else + sr_spew("Read %d/%d bytes (fd %d).", ret, count, serial->fd); +#endif return ret; -#endif } /** * Set serial parameters for the specified serial port. * + * @param serial Previously initialized serial port structure. * @param baudrate The baudrate to set. * @param bits The number of data bits to use. * @param parity The parity setting to use (0 = none, 1 = even, 2 = odd). @@ -224,61 +304,151 @@ SR_PRIV int serial_read(int fd, void *buf, size_t count) * * @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_PRIV int serial_set_params(struct sr_serial_dev_inst *serial, int baudrate, + int bits, int parity, int stopbits, + int flowcontrol, int rts, int dtr) { - sr_dbg("FD %d: Setting serial parameters.", fd); + if (!serial) { + sr_dbg("Invalid serial port."); + return SR_ERR; + } + + if (serial->fd == -1) { + sr_dbg("Cannot configure unopened serial port %s (fd %d).", + serial->port, serial->fd); + return SR_ERR; + } + + sr_spew("Setting serial parameters on port %s (fd %d).", serial->port, + serial->fd); #ifdef _WIN32 DCB dcb; if (!GetCommState(hdl, &dcb)) { - /* TODO: Error handling. */ + sr_err("Failed to get comm state on port %s (fd %d): %d.", + serial->port, serial->fd, GetLastError()); return SR_ERR; } switch (baudrate) { - /* TODO: Support for higher baud rates. */ - case 115200: - dcb.BaudRate = CBR_115200; + /* + * The baudrates 50/75/134/150/200/1800/230400/460800 do not seem to + * have documented CBR_* macros. + */ + case 110: + dcb.BaudRate = CBR_110; break; - case 57600: - dcb.BaudRate = CBR_57600; + case 300: + dcb.BaudRate = CBR_300; break; - case 38400: - dcb.BaudRate = CBR_38400; + case 600: + dcb.BaudRate = CBR_600; break; - case 19200: - dcb.BaudRate = CBR_19200; + case 1200: + dcb.BaudRate = CBR_1200; break; - case 9600: - dcb.BaudRate = CBR_9600; + case 2400: + dcb.BaudRate = CBR_2400; break; case 4800: dcb.BaudRate = CBR_4800; break; - case 2400: - dcb.BaudRate = CBR_2400; + case 9600: + dcb.BaudRate = CBR_9600; + break; + case 14400: + dcb.BaudRate = CBR_14400; /* Not available on Unix? */ + break; + case 19200: + dcb.BaudRate = CBR_19200; + break; + case 38400: + dcb.BaudRate = CBR_38400; + break; + case 57600: + dcb.BaudRate = CBR_57600; + break; + case 115200: + dcb.BaudRate = CBR_115200; + break; + case 128000: + dcb.BaudRate = CBR_128000; /* Not available on Unix? */ + break; + case 256000: + dcb.BaudRate = CBR_256000; /* Not available on Unix? */ break; default: sr_err("Unsupported baudrate: %d.", baudrate); return SR_ERR; } + sr_spew("Configuring baudrate to %d (%d).", baudrate, dcb.BaudRate); + + sr_spew("Configuring %d data bits.", bits); dcb.ByteSize = bits; - dcb.Parity = NOPARITY; /* TODO: Don't hardcode. */ - dcb.StopBits = ONESTOPBIT; /* TODO: Don't hardcode. */ + + sr_spew("Configuring %d stop bits.", stopbits); + switch (stopbits) { + /* Note: There's also ONE5STOPBITS == 1.5 (unneeded so far). */ + case 1: + dcb.StopBits = ONESTOPBIT; + break; + case 2: + dcb.StopBits = TWOSTOPBITS; + break; + default: + sr_err("Unsupported stopbits number: %d.", stopbits); + return SR_ERR; + } + + switch (parity) { + /* Note: There's also SPACEPARITY, MARKPARITY (unneeded so far). */ + case SERIAL_PARITY_NONE: + sr_spew("Configuring no parity."); + dcb.Parity = NOPARITY; + break; + case SERIAL_PARITY_EVEN: + sr_spew("Configuring even parity."); + dcb.Parity = EVENPARITY; + break; + case SERIAL_PARITY_ODD: + sr_spew("Configuring odd parity."); + dcb.Parity = ODDPARITY; + break; + default: + sr_err("Unsupported parity setting: %d.", parity); + return SR_ERR; + } + + if (rts != -1) { + sr_spew("Setting RTS %s.", rts ? "high" : "low"); + if (rts) + dcb.fRtsControl = RTS_CONTROL_ENABLE; + else + dcb.fRtsControl = RTS_CONTROL_DISABLE; + } + + if (dtr != -1) { + sr_spew("Setting DTR %s.", dtr ? "high" : "low"); + if (rts) + dcb.fDtrControl = DTR_CONTROL_ENABLE; + else + dcb.fDtrControl = DTR_CONTROL_DISABLE; + } if (!SetCommState(hdl, &dcb)) { - /* TODO: Error handling. */ + sr_err("Failed to set comm state on port %s (fd %d): %d.", + serial->port, serial->fd, GetLastError()); return SR_ERR; } #else struct termios term; speed_t baud; + int ret, controlbits; - sr_dbg("FD %d: Getting terminal settings.", fd); - if (tcgetattr(fd, &term) < 0) { - sr_err("tcgetattr() error: %s.", strerror(errno)); + if (tcgetattr(serial->fd, &term) < 0) { + sr_err("tcgetattr() error on port %s (fd %d): %s.", + serial->port, serial->fd, strerror(errno)); return SR_ERR; } @@ -347,21 +517,19 @@ SR_PRIV int serial_set_params(int fd, int baudrate, int bits, int parity, return SR_ERR; } - sr_dbg("FD %d: Configuring output baudrate to %d (%d).", - fd, baudrate, baud); + sr_spew("Configuring output baudrate to %d (%d).", baudrate, baud); if (cfsetospeed(&term, baud) < 0) { - sr_err("cfsetospeed() error: %ѕ.", strerror(errno)); + sr_err("cfsetospeed() error: %s.", strerror(errno)); return SR_ERR; } - sr_dbg("FD %d: Configuring input baudrate to %d (%d).", - fd, baudrate, baud); + sr_spew("Configuring input baudrate to %d (%d).", baudrate, baud); if (cfsetispeed(&term, baud) < 0) { - sr_err("cfsetispeed() error: %ѕ.", strerror(errno)); + sr_err("cfsetispeed() error: %s.", strerror(errno)); return SR_ERR; } - sr_dbg("FD %d: Configuring %d data bits.", fd, bits); + sr_spew("Configuring %d data bits.", bits); term.c_cflag &= ~CSIZE; switch (bits) { case 8: @@ -371,21 +539,21 @@ 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); + sr_err("Unsupported data bits number %d.", bits); return SR_ERR; } - sr_dbg("FD %d: Configuring %d stop bits.", fd, stopbits); + sr_spew("Configuring %d stop bits.", stopbits); term.c_cflag &= ~CSTOPB; switch (stopbits) { case 1: - /* Do nothing, a cleared CSTOPB entry means "1 stop bit". */ + term.c_cflag &= ~CSTOPB; break; case 2: term.c_cflag |= CSTOPB; break; default: - sr_err("Unsupported stopbits number: %d.", stopbits); + sr_err("Unsupported stopbits number %d.", stopbits); return SR_ERR; } @@ -394,18 +562,18 @@ 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); + sr_spew("Configuring no flow control."); break; case 1: - sr_dbg("FD %d: Configuring RTS/CTS flow control.", fd); + sr_spew("Configuring RTS/CTS flow control."); term.c_cflag |= CRTSCTS; break; case 2: - sr_dbg("FD %d: Configuring XON/XOFF flow control.", fd); + sr_spew("Configuring XON/XOFF flow control."); term.c_iflag |= IXON | IXOFF; break; default: - sr_err("Unsupported flow control setting: %d.", flowcontrol); + sr_err("Unsupported flow control setting %d.", flowcontrol); return SR_ERR; } @@ -413,47 +581,80 @@ 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); + sr_spew("Configuring no parity."); term.c_iflag |= IGNPAR; break; case SERIAL_PARITY_EVEN: - sr_dbg("FD %d: Configuring even parity.", fd); + sr_spew("Configuring even parity."); term.c_cflag |= PARENB; break; case SERIAL_PARITY_ODD: - sr_dbg("FD %d: Configuring odd parity.", fd); + sr_spew("Configuring odd parity."); term.c_cflag |= PARENB | PARODD; break; default: - sr_err("Unsupported parity setting: %d.", parity); + sr_err("Unsupported parity setting %d.", parity); return SR_ERR; } - /* Do NOT translate carriage return to newline on input. */ + /* 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); /* Write the configured settings. */ - if (tcsetattr(fd, TCSADRAIN, &term) < 0) { - sr_err("tcsetattr() error: %ѕ.", strerror(errno)); + if (tcsetattr(serial->fd, TCSADRAIN, &term) < 0) { + sr_err("tcsetattr() error: %s.", strerror(errno)); return SR_ERR; } + + if (rts != -1) { + sr_spew("Setting RTS %s.", rts ? "high" : "low"); + controlbits = TIOCM_RTS; + if ((ret = ioctl(serial->fd, rts ? TIOCMBIS : TIOCMBIC, + &controlbits)) < 0) { + sr_err("Error setting RTS: %s.", strerror(errno)); + return SR_ERR; + } + } + + if (dtr != -1) { + sr_spew("Setting DTR %s.", dtr ? "high" : "low"); + controlbits = TIOCM_DTR; + if ((ret = ioctl(serial->fd, dtr ? TIOCMBIS : TIOCMBIC, + &controlbits)) < 0) { + sr_err("Error setting DTR: %s.", strerror(errno)); + return SR_ERR; + } + } + #endif return SR_OK; } -#define SERIAL_COMM_SPEC "^(\\d+)/([78])([neo])([12])$" -SR_PRIV int serial_set_paramstr(int fd, const char *paramstr) +/** + * Set serial parameters for the specified serial port. + * + * @param serial Previously initialized serial port structure. + * @param paramstr A serial communication parameters string, in the form + * of /, for example "9600/8n1" or + * "600/7o2". + * + * @return SR_OK upon success, SR_ERR upon failure. + */ +#define SERIAL_COMM_SPEC "^(\\d+)/([78])([neo])([12])(.*)$" +SR_PRIV int serial_set_paramstr(struct sr_serial_dev_inst *serial, + const char *paramstr) { GRegex *reg; GMatchInfo *match; - int speed, databits, parity, stopbits; - char *mstr; + int speed, databits, parity, stopbits, rts, dtr, i; + char *mstr, **opts, **kv; speed = databits = parity = stopbits = 0; + rts = dtr = -1; reg = g_regex_new(SERIAL_COMM_SPEC, 0, 0, NULL); if (g_regex_match(reg, paramstr, 0, &match)) { if ((mstr = g_match_info_fetch(match, 1))) @@ -479,22 +680,80 @@ SR_PRIV int serial_set_paramstr(int fd, const char *paramstr) if ((mstr = g_match_info_fetch(match, 4))) stopbits = strtoul(mstr, NULL, 10); g_free(mstr); + if ((mstr = g_match_info_fetch(match, 5)) && mstr[0] != '\0') { + if (mstr[0] != '/') { + sr_dbg("missing separator before extra options"); + speed = 0; + } else { + /* A set of "key=value" options separated by / */ + opts = g_strsplit(mstr + 1, "/", 0); + for (i = 0; opts[i]; i++) { + kv = g_strsplit(opts[i], "=", 2); + if (!strncmp(kv[0], "rts", 3)) { + if (kv[1][0] == '1') + rts = 1; + else if (kv[1][0] == '0') + rts = 0; + else { + sr_dbg("invalid value for rts: %c", kv[1][0]); + speed = 0; + } + } else if (!strncmp(kv[0], "dtr", 3)) { + if (kv[1][0] == '1') + dtr = 1; + else if (kv[1][0] == '0') + dtr = 0; + else { + sr_dbg("invalid value for dtr: %c", kv[1][0]); + speed = 0; + } + } + g_strfreev(kv); + } + g_strfreev(opts); + } + } + g_free(mstr); } g_match_info_unref(match); g_regex_unref(reg); if (speed) - return serial_set_params(fd, speed, databits, parity, stopbits, 0); + return serial_set_params(serial, speed, databits, parity, stopbits, + 0, rts, dtr); else return SR_ERR_ARG; } -SR_PRIV int serial_readline(int fd, char **buf, int *buflen, - gint64 timeout_ms) +/** + * Read a line from the specified serial port. + * + * @param serial Previously initialized serial port structure. + * @param buf Buffer where to store the bytes that are read. + * @param buflen Size of the buffer. + * @param timeout_ms How long to wait for a line to come in. + * + * Reading stops when CR of LR is found, which is stripped from the buffer. + * + * @return SR_OK on success, SR_ERR on failure. + */ +SR_PRIV int serial_readline(struct sr_serial_dev_inst *serial, char **buf, + int *buflen, gint64 timeout_ms) { gint64 start; int maxlen, len; + if (!serial || serial->fd == -1) { + sr_dbg("Invalid serial port."); + return SR_ERR; + } + + if (serial->fd == -1) { + sr_dbg("Cannot use unopened serial port %s (fd %d).", + serial->port, serial->fd); + return -1; + } + timeout_ms *= 1000; start = g_get_monotonic_time(); @@ -504,7 +763,7 @@ SR_PRIV int serial_readline(int fd, char **buf, int *buflen, len = maxlen - *buflen - 1; if (len < 1) break; - len = serial_read(fd, *buf + *buflen, 1); + len = serial_read(serial, *buf + *buflen, 1); if (len > 0) { *buflen += len; *(*buf + *buflen) = '\0'; @@ -525,3 +784,86 @@ SR_PRIV int serial_readline(int fd, char **buf, int *buflen, return SR_OK; } + +/** + * Try to find a valid packet in a serial data stream. + * + * @param serial Previously initialized serial port structure. + * @param buf Buffer containing the bytes to write. + * @param count Size of the buffer. + * @param packet_size Size, in bytes, of a valid packet. + * @param is_valid Callback that assesses whether the packet is valid or not. + * @param timeout_ms The timeout after which, if no packet is detected, to + * abort scanning. + * @param baudrate The baudrate of the serial port. This parameter is not + * critical, but it helps fine tune the serial port polling + * delay. + * + * @return SR_OK if a valid packet is found within the given timeout, + * SR_ERR upon failure. + */ +SR_PRIV int serial_stream_detect(struct sr_serial_dev_inst *serial, + uint8_t *buf, size_t *buflen, + size_t packet_size, packet_valid_t is_valid, + uint64_t timeout_ms, int baudrate) +{ + uint64_t start, time, byte_delay_us; + size_t ibuf, i, maxlen; + int len; + + maxlen = *buflen; + + sr_dbg("Detecting packets on FD %d (timeout = %" PRIu64 + "ms, baudrate = %d).", serial->fd, timeout_ms, baudrate); + + if (maxlen < (packet_size / 2) ) { + sr_err("Buffer size must be at least twice the packet size."); + return SR_ERR; + } + + /* Assume 8n1 transmission. That is 10 bits for every byte. */ + byte_delay_us = 10 * (1000000 / baudrate); + start = g_get_monotonic_time(); + + i = ibuf = len = 0; + while (ibuf < maxlen) { + len = serial_read(serial, &buf[ibuf], 1); + if (len > 0) { + ibuf += len; + } else if (len == 0) { + sr_spew("Error: Only read 0 bytes."); + } else { + /* Error reading byte, but continuing anyway. */ + } + + time = g_get_monotonic_time() - start; + time /= 1000; + + if ((ibuf - i) >= packet_size) { + /* We have at least a packet's worth of data. */ + if (is_valid(&buf[i])) { + sr_spew("Found valid %d-byte packet after " + "%" PRIu64 "ms.", (ibuf - i), time); + *buflen = ibuf; + return SR_OK; + } else { + sr_spew("Got %d bytes, but not a valid " + "packet.", (ibuf - i)); + } + /* Not a valid packet. Continue searching. */ + i++; + } + if (time >= timeout_ms) { + /* Timeout */ + sr_dbg("Detection timed out after %dms.", time); + break; + } + g_usleep(byte_delay_us); + } + + *buflen = ibuf; + + sr_err("Didn't find a valid packet (read %d bytes).", *buflen); + + return SR_ERR; +}