diff options
| author | Peter Hurley <peter@hurleysoftware.com> | 2014-09-03 01:39:10 +0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-09-09 03:21:35 +0400 |
| commit | a6eec92ec0815ce8ce57e4746e9f717d4146d869 (patch) | |
| tree | 1362131aff20ceb27fb8575d26a30ff081f3c28c /drivers/tty/serial/serial_core.c | |
| parent | 95562e7fdfe3fae2a10bb7ab16fc1260fe8dd810 (diff) | |
| download | linux-a6eec92ec0815ce8ce57e4746e9f717d4146d869.tar.xz | |
Revert "serial: uart: add hw flow control support configuration"
This reverts commit 06aa82e498c144c7784a6f3d3b55458b272d6146.
This commit purports to enable auto CTS flow control for the 8250
UART driver. However, the 8250 UART driver already supports auto
CTS flow control via UART_CAP_AFE and UART_CAP_EFR. Indeed, this
patch introduces another DT attribute for which an existing firmware
flag already exists ("auto-flow-control"). Furthermore, the use of
UPF_HARD_FLOW requires the UART driver to define .throttle and
.unthrottle methods, neither of which are defined for the 8250 UART
driver (which will result in a NULL ptr dereference). Finally, this patch
supposes to fix existing bugs in the serial core for auto CTS-enabled
hardware, but does not include the class of hardware for which these
bugs exist.
CC: Murali Karicheri <m-karicheri2@ti.com>
CC: Rob Herring <robh+dt@kernel.org>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/serial/serial_core.c')
| -rw-r--r-- | drivers/tty/serial/serial_core.c | 12 |
1 files changed, 3 insertions, 9 deletions
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index 079f18d84b03..2e57d5b6347d 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -175,12 +175,8 @@ static int uart_port_startup(struct tty_struct *tty, struct uart_state *state, if (tty->termios.c_cflag & CBAUD) uart_set_mctrl(uport, TIOCM_RTS | TIOCM_DTR); } - /* - * if hw support flow control without software intervention, - * then skip the below check - */ - if (tty_port_cts_enabled(port) && - !(uport->flags & UPF_HARD_FLOW)) { + + if (tty_port_cts_enabled(port)) { spin_lock_irq(&uport->lock); if (!(uport->ops->get_mctrl(uport) & TIOCM_CTS)) tty->hw_stopped = 1; @@ -2789,9 +2785,7 @@ void uart_handle_cts_change(struct uart_port *uport, unsigned int status) uport->icount.cts++; - /* skip below code if the hw flow control is supported */ - if (tty_port_cts_enabled(port) && - !(uport->flags & UPF_HARD_FLOW)) { + if (tty_port_cts_enabled(port)) { if (tty->hw_stopped) { if (status) { tty->hw_stopped = 0; |