This change adds a flag to indicate that a UART is has an external means
of synchronising its FIFO, without needing CTSRTS or XON/XOFF.
This allows us to use the throttle/unthrottle callbacks, without having
to claim other methods of flow control.
Signed-off-by: Jeremy Kerr <jk@xxxxxxxxxx>
Tested-by: Eddie James <eajames@xxxxxxxxxxxxxxxxxx>
--
v2:
- simplify status mask checks
---
drivers/tty/serial/serial_core.c | 4 ++--
include/linux/serial_core.h | 1 +
2 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 0466f9f08a91..c47158c93202 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -674,8 +674,8 @@ static void uart_send_xchar(struct tty_struct *tty, char ch)
static void uart_throttle(struct tty_struct *tty)
{
struct uart_state *state = tty->driver_data;
+ upstat_t mask = UPSTAT_SYNC_FIFO;
struct uart_port *port;
- upstat_t mask = 0;
port = uart_port_ref(state);
if (!port)
@@ -703,8 +703,8 @@ static void uart_throttle(struct tty_struct *tty)
static void uart_unthrottle(struct tty_struct *tty)
{
struct uart_state *state = tty->driver_data;
+ upstat_t mask = UPSTAT_SYNC_FIFO;
struct uart_port *port;
- upstat_t mask = 0;
port = uart_port_ref(state);
if (!port)
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 1d356105f25a..d224961e1346 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -233,6 +233,7 @@ struct uart_port {
#define UPSTAT_AUTORTS ((__force upstat_t) (1 << 2))
#define UPSTAT_AUTOCTS ((__force upstat_t) (1 << 3))
#define UPSTAT_AUTOXOFF ((__force upstat_t) (1 << 4))
+#define UPSTAT_SYNC_FIFO ((__force upstat_t) (1 << 5))
int hw_stopped; /* sw-assisted CTS flow state */
unsigned int mctrl; /* current modem ctrl settings */
--
2.14.1
--
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