From c5f78b1fe4e5baf4c4ca30377c2d7e06e2e391ec Mon Sep 17 00:00:00 2001 From: Jeremy Kerr Date: Tue, 27 Mar 2018 11:48:24 +0800 Subject: [PATCH] serial: Introduce UPSTAT_SYNC_FIFO for synchronised FIFOs 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 Tested-by: Eddie James Tested-by: Joel Stanley Signed-off-by: Greg Kroah-Hartman --- 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 */ -- 2.45.2