diff options
| author | Russell King <rmk+kernel@arm.linux.org.uk> | 2012-04-17 16:23:14 (GMT) |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2012-11-04 11:25:56 (GMT) |
| commit | 9aba8d5b011193c8e01d565c5b585df5b94f1db2 (patch) | |
| tree | 4f45580d7310ea7ea7dba87a237732f0580ecb36 /drivers/tty | |
| parent | dba05832cbe4f305dfd998fb26d7c685d91fbbd8 (diff) | |
| download | linux-fsl-qoriq-9aba8d5b011193c8e01d565c5b585df5b94f1db2.tar.xz | |
SERIAL: core: add throttle/unthrottle callbacks for hardware assisted flow control
Add two callbacks for hardware assisted flow control; we need to know
when the tty layers want us to stop and restart due to their buffer
levels.
Call a driver specific throttle/unthrottle function if and only if the
driver indicates that it is using an enabled hardware assisted flow
control method, otherwise fall back to the non-hardware assisted
methods.
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'drivers/tty')
| -rw-r--r-- | drivers/tty/serial/serial_core.c | 31 |
1 files changed, 27 insertions, 4 deletions
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index 9d8796e..098bb99 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -610,27 +610,50 @@ 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; + struct uart_port *port = state->uart_port; + uint32_t mask = 0; if (I_IXOFF(tty)) + mask |= UPF_SOFT_FLOW; + if (tty->termios.c_cflag & CRTSCTS) + mask |= UPF_HARD_FLOW; + + if (port->flags & mask) { + port->ops->throttle(port); + mask &= ~port->flags; + } + + if (mask & UPF_SOFT_FLOW) uart_send_xchar(tty, STOP_CHAR(tty)); - if (tty->termios.c_cflag & CRTSCTS) - uart_clear_mctrl(state->uart_port, TIOCM_RTS); + if (mask & UPF_HARD_FLOW) + uart_clear_mctrl(port, TIOCM_RTS); } static void uart_unthrottle(struct tty_struct *tty) { struct uart_state *state = tty->driver_data; struct uart_port *port = state->uart_port; + uint32_t mask = 0; - if (I_IXOFF(tty)) { + if (I_IXOFF(tty)) + mask |= UPF_SOFT_FLOW; + if (tty->termios.c_cflag & CRTSCTS) + mask |= UPF_HARD_FLOW; + + if (port->flags & mask) { + port->ops->unthrottle(port); + mask &= ~port->flags; + } + + if (mask & UPF_SOFT_FLOW) { if (port->x_char) port->x_char = 0; else uart_send_xchar(tty, START_CHAR(tty)); } - if (tty->termios.c_cflag & CRTSCTS) + if (mask & UPF_HARD_FLOW) uart_set_mctrl(port, TIOCM_RTS); } |