This patch makes serial_core to use hardware flow port flags instead of using
the fixed RTS/CTS.
Signed-off-by: Aristeu Rozanski <aris@xxxxxxxxx>
---
drivers/serial/serial_core.c | 154 ++++++++++++++++++++++++++++++++++++-------
include/linux/serial_core.h | 2
2 files changed, 133 insertions(+), 23 deletions(-)
--- linux-next.orig/drivers/serial/serial_core.c 2008-09-25 11:50:49.000000000 -0400
+++ linux-next/drivers/serial/serial_core.c 2008-09-25 11:56:00.000000000 -0400
@@ -133,6 +133,49 @@ uart_update_mctrl(struct uart_port *port
#define uart_set_mctrl(port, set) uart_update_mctrl(port, set, 0)
#define uart_clear_mctrl(port, clear) uart_update_mctrl(port, 0, clear)
+static void uart_flow_input_start(struct uart_port *port)
+{
+ unsigned int bit;
+
+ if (port->flags & UPF_FLOW_RTSXOFF)
+ bit = TIOCM_RTS;
+ else if (port->flags & UPF_FLOW_DTRXOFF)
+ bit = TIOCM_DTR;
+ else
+ return;
+
+ uart_set_mctrl(port, bit);
+}
+
+static void uart_flow_input_stop(struct uart_port *port)
+{
+ unsigned int bit;
+
+ if (port->flags & UPF_FLOW_RTSXOFF)
+ bit = TIOCM_RTS;
+ else if (port->flags & UPF_FLOW_DTRXOFF)
+ bit = TIOCM_DTR;
+ else
+ return;
+
+ uart_clear_mctrl(port, bit);
+}
+
+int uart_flow_output_allowed(struct uart_port *port)
+{
+ unsigned int bit;
+
+ if (port->flags & UPF_FLOW_CTSXON)
+ bit = TIOCM_CTS;
+ else if (port->flags & UPF_FLOW_DSRXON)
+ bit = TIOCM_DSR;
+ else
+ return 1;
+
+ return port->ops->get_mctrl(port) & bit;
+}
+EXPORT_SYMBOL(uart_flow_output_allowed);
+
/*
* Startup the port. This will be called once per open. All calls
* will be serialised by the per-port mutex.
@@ -183,16 +226,16 @@ static int uart_startup(struct uart_stat
* Setup the RTS and DTR signals once the
* port is open and ready to respond.
*/
- if (info->port.tty->termios->c_cflag & CBAUD)
- uart_set_mctrl(port, TIOCM_RTS | TIOCM_DTR);
+ if (info->port.tty->termios->c_cflag & CBAUD) {
+ uart_set_mctrl(port, TIOCM_DTR);
+ uart_flow_input_start(port);
+ }
}
- if (info->flags & UIF_CTS_FLOW) {
- spin_lock_irq(&port->lock);
- if (!(port->ops->get_mctrl(port) & TIOCM_CTS))
- info->port.tty->hw_stopped = 1;
- spin_unlock_irq(&port->lock);
- }
+ spin_lock_irq(&port->lock);
+ if (!uart_flow_output_allowed(port))
+ info->port.tty->hw_stopped = 1;
+ spin_unlock_irq(&port->lock);
info->flags |= UIF_INITIALIZED;
@@ -609,8 +652,7 @@ static void uart_throttle(struct tty_str
if (I_IXOFF(tty))
uart_send_xchar(tty, STOP_CHAR(tty));
- if (tty->termios->c_cflag & CRTSCTS)
- uart_clear_mctrl(state->port, TIOCM_RTS);
+ uart_flow_input_stop(state->port);
}
static void uart_unthrottle(struct tty_struct *tty)
@@ -625,8 +667,7 @@ static void uart_unthrottle(struct tty_s
uart_send_xchar(tty, START_CHAR(tty));
}
- if (tty->termios->c_cflag & CRTSCTS)
- uart_set_mctrl(port, TIOCM_RTS);
+ uart_flow_input_start(port);
}
static int uart_get_info(struct uart_state *state,
@@ -1208,25 +1249,33 @@ static void uart_set_termios(struct tty_
/* Handle transition away from B0 status */
if (!(old_termios->c_cflag & CBAUD) && (cflag & CBAUD)) {
- unsigned int mask = TIOCM_DTR;
- if (!(cflag & CRTSCTS) ||
- !test_bit(TTY_THROTTLED, &tty->flags))
- mask |= TIOCM_RTS;
- uart_set_mctrl(state->port, mask);
+ uart_set_mctrl(state->port, TIOCM_DTR);
+ if (!test_bit(TTY_THROTTLED, &tty->flags))
+ uart_flow_input_start(state->port);
}
/* Handle turning off CRTSCTS */
if ((old_termios->c_cflag & CRTSCTS) && !(cflag & CRTSCTS)) {
spin_lock_irqsave(&state->port->lock, flags);
- tty->hw_stopped = 0;
- __uart_start(tty);
+ tty->termiox->x_cflag &= ~(RTSXOFF | CTSXON);
+ state->port->flags &= ~(UPF_FLOW_RTSXOFF | UPF_FLOW_CTSXON);
+ if (uart_flow_output_allowed(state->port)) {
+ tty->hw_stopped = 0;
+ __uart_start(tty);
+ }
spin_unlock_irqrestore(&state->port->lock, flags);
}
/* Handle turning on CRTSCTS */
if (!(old_termios->c_cflag & CRTSCTS) && (cflag & CRTSCTS)) {
spin_lock_irqsave(&state->port->lock, flags);
- if (!(state->port->ops->get_mctrl(state->port) & TIOCM_CTS)) {
+ tty->termiox->x_cflag |= (RTSXOFF | CTSXON);
+ state->port->flags |= (UPF_FLOW_RTSXOFF | UPF_FLOW_CTSXON);
+ /* not supported right now */
+ tty->termiox->x_cflag &= ~(DTRXOFF | DSRXON);
+ state->port->flags &= ~(UPF_FLOW_DTRXOFF | UPF_FLOW_DSRXON);
+
+ if (!uart_flow_output_allowed(state->port)) {
tty->hw_stopped = 1;
state->port->ops->stop_tx(state->port);
}
@@ -1454,10 +1503,12 @@ static void uart_update_termios(struct u
uart_change_speed(state, NULL);
/*
- * And finally enable the RTS and DTR signals.
+ * And finally enable the DTR signal.
*/
- if (tty->termios->c_cflag & CBAUD)
- uart_set_mctrl(port, TIOCM_DTR | TIOCM_RTS);
+ if (tty->termios->c_cflag & CBAUD) {
+ uart_set_mctrl(port, TIOCM_DTR);
+ uart_flow_input_start(port);
+ }
}
}
@@ -2295,9 +2346,66 @@ static void uart_poll_put_char(struct tt
#ifdef TCSETX
static int uart_set_termiox(struct tty_struct *tty, struct termiox *new)
{
+ struct uart_state *state = tty->driver_data;
+ struct ktermios old_termios;
+ unsigned long flags;
+
+ if (((new->x_cflag & RTSXOFF) && (new->x_cflag & DTRXOFF)) ||
+ ((new->x_cflag & CTSXON) && (new->x_cflag & DSRXON)))
+ /* not supported (yet?) */
+ return 1;
+
+ /* saving current settings */
+ memcpy(&old_termios, tty->termios, sizeof(old_termios));
+
+ /* stop input flow control */
+ uart_flow_input_stop(state->port);
+
+ /* import the settings */
tty->termiox->x_cflag = new->x_cflag &
(RTSXOFF | CTSXON | DTRXOFF | DSRXON);
+ state->port->flags = 0;
+ if (new->x_cflag & RTSXOFF)
+ state->port->flags |= UPF_FLOW_RTSXOFF;
+ if (new->x_cflag & CTSXON)
+ state->port->flags |= UPF_FLOW_CTSXON;
+ if (new->x_cflag & DTRXOFF)
+ state->port->flags |= UPF_FLOW_DTRXOFF;
+ if (new->x_cflag & DSRXON)
+ state->port->flags |= UPF_FLOW_DSRXON;
+ if (new->x_cflag != (RTSXOFF | CTSXON))
+ tty->termios->c_cflag &= ~CRTSCTS;
+
+ /*
+ * we need to call uart_change_speed() to propagate the changes like
+ * disabling CRTSCTS and enabling/disabling interrupts
+ */
+ uart_change_speed(state, &old_termios);
+
+ /* and restart it if it's possible */
+ if ((tty->termios->c_cflag & CBAUD) &&
+ !(test_bit(TTY_THROTTLED, &tty->flags)))
+ uart_flow_input_start(state->port);
+
+ /*
+ * if the TX wasn't enabled before and now it's possible to transmit
+ * due the changes, do it
+ */
+ if (tty->hw_stopped && uart_flow_output_allowed(state->port)) {
+ spin_lock_irqsave(&state->port->lock, flags);
+ tty->hw_stopped = 0;
+ __uart_start(tty);
+ spin_unlock_irqrestore(&state->port->lock, flags);
+ } else if (!tty->hw_stopped) {
+ spin_lock_irqsave(&state->port->lock, flags);
+ if (!uart_flow_output_allowed(state->port)) {
+ tty->hw_stopped = 1;
+ state->port->ops->stop_tx(state->port);
+ }
+ spin_unlock_irqrestore(&state->port->lock, flags);
+ }
+
return 0;
}
#endif
--- linux-next.orig/include/linux/serial_core.h 2008-09-25 11:53:57.000000000 -0400
+++ linux-next/include/linux/serial_core.h 2008-09-25 11:56:00.000000000 -0400
@@ -558,6 +558,8 @@ uart_insert_char(struct uart_port *port,
tty_insert_flip_char(tty, 0, TTY_OVERRUN);
}
+int uart_flow_output_allowed(struct uart_port *port);
+
/*
* UART_ENABLE_MS - determine if port should enable modem status irqs
*/
--
Aristeu
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