-#else
-/*
-> Problems to take into account are:
-> -1- Interrupts that empty part of the buffer.
-> -2- page faults on the access to userspace.
-> -3- Other processes that are also trying to do a "write".
-*/
-
-int gs_write(struct tty_struct * tty,
- const unsigned char *buf, int count)
-{
- struct gs_port *port;
- int c, total = 0;
- int t;
- unsigned long flags;
-
- func_enter ();
-
- /* The standard serial driver returns 0 in this case.
- That sounds to me as "No error, I just didn't get to writing any
- bytes. Feel free to try again."
- The "official" way to write n bytes from buf is:
-
- for (nwritten = 0;nwritten < n;nwritten += rv) {
- rv = write (fd, buf+nwritten, n-nwritten);
- if (rv < 0) break; // Error: bail out. //
- }
-
- which will loop endlessly in this case. The manual page for write
- agrees with me. In practise almost everybody writes
- "write (fd, buf,n);" but some people might have had to deal with
- incomplete writes in the past and correctly implemented it by now...
- */
-
- if (!tty) return -EIO;
-
- port = tty->driver_data;
- if (!port || !port->xmit_buf)
- return -EIO;
-
- local_save_flags(flags);
- while (1) {
- cli();
- c = count;
-
- /* This is safe because we "OWN" the "head". Noone else can
- change the "head": we own the port_write_mutex. */
- /* Don't overrun the end of the buffer */
- t = SERIAL_XMIT_SIZE - port->xmit_head;
- if (t < c) c = t;
-
- /* This is safe because the xmit_cnt can only decrease. This
- would increase "t", so we might copy too little chars. */
- /* Don't copy past the "head" of the buffer */
- t = SERIAL_XMIT_SIZE - 1 - port->xmit_cnt;
- if (t < c) c = t;
-
- /* Can't copy more? break out! */
- if (c <= 0) {
- local_restore_flags(flags);
- break;
- }
- memcpy(port->xmit_buf + port->xmit_head, buf, c);
- port->xmit_head = ((port->xmit_head + c) &
- (SERIAL_XMIT_SIZE-1));
- port->xmit_cnt += c;
- local_restore_flags(flags);
- buf += c;
- count -= c;
- total += c;
- }
-
- if (port->xmit_cnt &&
- !tty->stopped &&
- !tty->hw_stopped &&
- !(port->flags & GS_TX_INTEN)) {
- port->flags |= GS_TX_INTEN;
- port->rd->enable_tx_interrupts (port);
- }
- func_exit ();
- return total;
-}
-
-#endif