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 <stefan.tauner@alumni.tuwien.ac.at>
Acked-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
diff --git a/serial.c b/serial.c
index d1e2cea..8e27aa0 100644
--- a/serial.c
+++ b/serial.c
@@ -431,3 +431,75 @@
}
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;
+}