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SubjectRe: [PATCH 01/26] Revert "serial: uart: add hw flow control support configuration"
Peter,

On 09/02/2014 05:39 PM, Peter Hurley wrote:
> 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.

What is this? What class of hardware are you referring to?

As discussed, I will send an updated patch for this as discussed..

Regards,

Murali
>
> CC: Murali Karicheri<m-karicheri2@ti.com>
> CC: Rob Herring<robh+dt@kernel.org>
> Signed-off-by: Peter Hurley<peter@hurleysoftware.com>
> ---
> Documentation/devicetree/bindings/serial/of-serial.txt | 1 -
> drivers/tty/serial/8250/8250_core.c | 6 ++----
> drivers/tty/serial/of_serial.c | 4 ----
> drivers/tty/serial/serial_core.c | 12 +++---------
> 4 files changed, 5 insertions(+), 18 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/serial/of-serial.txt b/Documentation/devicetree/bindings/serial/of-serial.txt
> index 7705477..1928a3e 100644
> --- a/Documentation/devicetree/bindings/serial/of-serial.txt
> +++ b/Documentation/devicetree/bindings/serial/of-serial.txt
> @@ -37,7 +37,6 @@ Optional properties:
> - auto-flow-control: one way to enable automatic flow control support. The
> driver is allowed to detect support for the capability even without this
> property.
> -- has-hw-flow-control: the hardware has flow control capability.
>
> Example:
>
> diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
> index 7a91c6d..109da60 100644
> --- a/drivers/tty/serial/8250/8250_core.c
> +++ b/drivers/tty/serial/8250/8250_core.c
> @@ -2333,11 +2333,9 @@ 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;
> diff --git a/drivers/tty/serial/of_serial.c b/drivers/tty/serial/of_serial.c
> index 68d4455..27981e2 100644
> --- a/drivers/tty/serial/of_serial.c
> +++ b/drivers/tty/serial/of_serial.c
> @@ -183,10 +183,6 @@ static int of_platform_serial_probe(struct platform_device *ofdev)
> "auto-flow-control"))
> port8250.capabilities |= UART_CAP_AFE;
>
> - if (of_property_read_bool(ofdev->dev.of_node,
> - "has-hw-flow-control"))
> - port8250.port.flags |= UPF_HARD_FLOW;
> -
> ret = serial8250_register_8250_port(&port8250);
> break;
> }
> diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
> index c2f90ec..261e49e 100644
> --- a/drivers/tty/serial/serial_core.c
> +++ b/drivers/tty/serial/serial_core.c
> @@ -174,12 +174,8 @@ 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;
> @@ -2777,9 +2773,7 @@ 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;



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