From 00e1608501a0eb270df80a31f0dd0b327b202059 Mon Sep 17 00:00:00 2001 From: Stefan Tauner Date: Mon, 1 Apr 2013 00:45:38 +0000 Subject: Replace sp_sync_read_timeout() with serialport_read_nonblock() It seems useful to have a generic and platform-independent method to read and write to a serial port without blocking. This is the read part. It stores the current blocking properties before disabling blocking and restores them after reading. The timeout is implemented as previously by retrying every millisecond until the timeout is reached or enough characters are available. Corresponding to flashrom svn r1661. Signed-off-by: Stefan Tauner Acked-by: Stefan Tauner --- serial.c | 70 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 70 insertions(+) (limited to 'serial.c') diff --git a/serial.c b/serial.c index 9a759ae..d1e2cea 100644 --- a/serial.c +++ b/serial.c @@ -361,3 +361,73 @@ int serialport_read(unsigned char *buf, unsigned int readcnt) return 0; } + +/* Tries up to timeout ms to read readcnt characters and places them into the array starting at c. Returns + * 0 on success, positive values on temporary errors (e.g. timeouts) and negative ones on permanent errors. + * If really_read is not NULL, this function sets its contents to the number of bytes read successfully. */ +int serialport_read_nonblock(unsigned char *c, unsigned int readcnt, unsigned int timeout, unsigned int *really_read) +{ + int ret = 1; + /* disable blocked i/o and declare platform-specific variables */ +#ifdef _WIN32 + DWORD rv; + COMMTIMEOUTS oldTimeout; + COMMTIMEOUTS newTimeout = { + .ReadIntervalTimeout = MAXDWORD, + .ReadTotalTimeoutMultiplier = 0, + .ReadTotalTimeoutConstant = 0, + .WriteTotalTimeoutMultiplier = 0, + .WriteTotalTimeoutConstant = 0 + }; + if(!GetCommTimeouts(sp_fd, &oldTimeout)) { + msg_perr_strerror("Could not get serial port timeout settings: "); + return -1; + } + if(!SetCommTimeouts(sp_fd, &newTimeout)) { +#else + ssize_t rv; + const int flags = fcntl(sp_fd, F_GETFL); + if (fcntl(sp_fd, F_SETFL, flags | O_NONBLOCK) != 0) { +#endif + msg_perr_strerror("Could not set serial port timeout settings %s"); + return -1; + } + + int i; + int rd_bytes = 0; + for (i = 0; i < timeout; i++) { + msg_pspew("readcnt %d rd_bytes %d\n", readcnt, rd_bytes); +#ifdef _WIN32 + ReadFile(sp_fd, c + rd_bytes, readcnt - rd_bytes, &rv, NULL); + msg_pspew("read %lu bytes\n", rv); +#else + rv = read(sp_fd, c + rd_bytes, readcnt - rd_bytes); + msg_pspew("read %zd bytes\n", rv); +#endif + if ((rv == -1) && (errno != EAGAIN)) { + msg_perr_strerror("Serial port read error: "); + ret = -1; + break; + } + if (rv > 0) + rd_bytes += rv; + if (rd_bytes == readcnt) { + ret = 0; + break; + } + internal_delay(1000); /* 1ms units */ + } + if (really_read != NULL) + *really_read = rd_bytes; + + /* restore original blocking behavior */ +#ifdef _WIN32 + if (!SetCommTimeouts(sp_fd, &oldTimeout)) { +#else + if (fcntl(sp_fd, F_SETFL, flags) != 0) { +#endif + msg_perr_strerror("Could not restore serial port timeout settings: %s\n"); + ret = -1; + } + return ret; +} -- cgit v1.1