[PATCH 3/5] tty: serial: 8250 core: allow to set ->throttle / ->unthrottle callbacks

Sebastian Andrzej Siewior
2014-07-16T14:46:22Z

The omap uart provides support for HW assisted flow control. What is
missing is the support to throttle / unthrottle callbacks which are used
by the omap-serial driver at the moment.
This patch adds the callbacks. It should be safe to add them since they
are only invovked from the serial_core (uart_throttle()) if the feature
flags are set.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
drivers/tty/serial/8250/8250_core.c | 14 ++++++++++++++
include/linux/serial_core.h | 2 ++
2 files changed, 16 insertions(+)

diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index bd0e1897..714f954 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -1320,6 +1320,16 @@ static void serial8250_start_tx(struct uart_port *port)
}
}

+static void serial8250_throttle(struct uart_port *port)
+{
+ port->throttle(port);
+}
+
+static void serial8250_unthrottle(struct uart_port *port)
+{
+ port->unthrottle(port);
+}
+
static void serial8250_stop_rx(struct uart_port *port)
{
struct uart_8250_port *up =
@@ -2752,6 +2762,8 @@ static struct uart_ops serial8250_pops = {
.get_mctrl = serial8250_get_mctrl,
.stop_tx = serial8250_stop_tx,
.start_tx = serial8250_start_tx,
+ .throttle = serial8250_throttle,
+ .unthrottle = serial8250_unthrottle,
.stop_rx = serial8250_stop_rx,
.enable_ms = serial8250_enable_ms,
.break_ctl = serial8250_break_ctl,
@@ -3300,6 +3312,8 @@ int serial8250_register_8250_port(struct uart_8250_port *up)
uart->port.fifosize = up->port.fifosize;
uart->tx_loadsz = up->tx_loadsz;
uart->capabilities = up->capabilities;
+ uart->port.throttle = up->port.throttle;
+ uart->port.unthrottle = up->port.unthrottle;

/* Take tx_loadsz from fifosize if it wasn't set separately */
if (uart->port.fifosize && !uart->tx_loadsz)
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 6f20ff0..c380af2 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -124,6 +124,8 @@ struct uart_port {
struct ktermios *old);
int (*startup)(struct uart_port *port);
void (*shutdown)(struct uart_port *port);
+ void (*throttle)(struct uart_port *port);
+ void (*unthrottle)(struct uart_port *port);
int (*handle_irq)(struct uart_port *);
void (*pm)(struct uart_port *, unsigned int state,
unsigned int old);
--
2.0.1