From: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
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 invoked from the serial_core (uart_throttle()) if the feature
flags are set.
Reviewed-by: Tony Lindgren <tony@xxxxxxxxxxx>
Tested-by: Tony Lindgren <tony@xxxxxxxxxxx>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
(cherry picked from commit 234abab143aef82c0ef1f2de409c0db96b666f3c)
Signed-off-by: Chang Rebecca Swee Fun <rebecca.swee.fun.chang@xxxxxxxxx>
---
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 97b4d33..70d68d5 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -1319,6 +1319,16 @@ 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 = up_to_u8250p(port);
@@ -2913,6 +2923,8 @@ 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,
@@ -3468,6 +3480,8 @@ int serial8250_register_8250_port(struct uart_8250_port *up)
uart->capabilities = up->capabilities;
uart->rs485_config = up->rs485_config;
uart->rs485 = up->rs485;
+ 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 689467f..a6aa89c 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);
--
1.7.9.5
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