diff options
| author | Peter Hurley <peter@hurleysoftware.com> | 2014-09-02 17:39:10 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-09-08 16:21:35 -0700 |
| commit | a6eec92ec0815ce8ce57e4746e9f717d4146d869 (patch) | |
| tree | 1362131aff20ceb27fb8575d26a30ff081f3c28c /drivers/tty/serial/8250 | |
| parent | 95562e7fdfe3fae2a10bb7ab16fc1260fe8dd810 (diff) | |
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/8250')
| -rw-r--r-- | drivers/tty/serial/8250/8250_core.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c index b28ed1beb50f..46c1f5fc44d3 100644 --- a/drivers/tty/serial/8250/8250_core.c +++ b/drivers/tty/serial/8250/8250_core.c @@ -2319,11 +2319,9 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios, * the trigger, or the MCR RTS bit is cleared. In the case where * the remote UART is not using CTS auto flow control, we must * have sufficient FIFO entries for the latency of the remote - * UART to respond. IOW, at least 32 bytes of FIFO. Also enable - * AFE if hw flow control is supported + * UART to respond. IOW, at least 32 bytes of FIFO. */ - if ((up->capabilities & UART_CAP_AFE && (port->fifosize >= 32)) || - (port->flags & UPF_HARD_FLOW)) { + if (up->capabilities & UART_CAP_AFE && port->fifosize >= 32) { up->mcr &= ~UART_MCR_AFE; if (termios->c_cflag & CRTSCTS) up->mcr |= UART_MCR_AFE; |