From ae3d83765cbb306696b3e0caa92e535e522b32d2 Mon Sep 17 00:00:00 2001 From: Stefan Tauner Date: Mon, 1 Apr 2013 00:45:45 +0000 Subject: Introduce serialport_write_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 write part. This allows to get rid of the explicit temporary disabling of blocking I/O in serprog's sp_synchronize(). Corresponding to flashrom svn r1662. Signed-off-by: Stefan Tauner Acked-by: Stefan Tauner --- serial.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 72 insertions(+) (limited to 'serial.c') diff --git a/serial.c b/serial.c index d1e2cea..8e27aa0 100644 --- a/serial.c +++ b/serial.c @@ -431,3 +431,75 @@ int serialport_read_nonblock(unsigned char *c, unsigned int readcnt, unsigned in } return ret; } + +/* Tries up to timeout ms to write writecnt characters from the array starting at buf. Returns + * 0 on success, positive values on temporary errors (e.g. timeouts) and negative ones on permanent errors. + * If really_wrote is not NULL, this function sets its contents to the number of bytes written successfully. */ +int serialport_write_nonblock(unsigned char *buf, unsigned int writecnt, unsigned int timeout, unsigned int *really_wrote) +{ + 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)) { + msg_perr_strerror("Could not set serial port timeout settings: "); + return -1; + } +#else + ssize_t rv; + const int flags = fcntl(sp_fd, F_GETFL); + fcntl(sp_fd, F_SETFL, flags | O_NONBLOCK); +#endif + + int i; + int wr_bytes = 0; + for (i = 0; i < timeout; i++) { + msg_pspew("writecnt %d wr_bytes %d\n", writecnt, wr_bytes); +#ifdef _WIN32 + WriteFile(sp_fd, buf + wr_bytes, writecnt - wr_bytes, &rv, NULL); + msg_pspew("wrote %lu bytes\n", rv); +#else + rv = write(sp_fd, buf + wr_bytes, writecnt - wr_bytes); + msg_pspew("wrote %zd bytes\n", rv); +#endif + if ((rv == -1) && (errno != EAGAIN)) { + msg_perr_strerror("Serial port write error: "); + ret = -1; + break; + } + if (rv > 0) { + wr_bytes += rv; + if (wr_bytes == writecnt) { + msg_pspew("write successful\n"); + ret = 0; + break; + } + } + internal_delay(1000); /* 1ms units */ + } + if (really_wrote != NULL) + *really_wrote = wr_bytes; + + /* restore original blocking behavior */ +#ifdef _WIN32 + if (!SetCommTimeouts(sp_fd, &oldTimeout)) { + msg_perr_strerror("Could not restore serial port timeout settings: "); +#else + if (fcntl(sp_fd, F_SETFL, flags) != 0) { +#endif + return -1; + } + return ret; +} -- cgit v1.1