Re: [PATCH v2 1/2] serial: 8250_early: do not save and restore IER in write callback

From: Peter Hurley
Date: Tue Oct 27 2015 - 09:54:45 EST


Hi Masahiro,

On 10/24/2015 12:17 AM, Masahiro Yamada wrote:
> The IER has already been masked in early_serial8250_setup(), there is
> no reason to save and restore it every time early_serial8250_write()
> is called.
>
> Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
> ---
>
> drivers/tty/serial/8250/8250_early.c | 12 ------------
> 1 file changed, 12 deletions(-)
>
> diff --git a/drivers/tty/serial/8250/8250_early.c b/drivers/tty/serial/8250/8250_early.c
> index 7aff3d8..559b681 100644
> --- a/drivers/tty/serial/8250/8250_early.c
> +++ b/drivers/tty/serial/8250/8250_early.c
> @@ -99,20 +99,8 @@ static void __init early_serial8250_write(struct console *console,
> {
> struct earlycon_device *device = console->data;
> struct uart_port *port = &device->port;
> - unsigned int ier;
> -
> - /* Save the IER and disable interrupts preserving the UUE bit */
> - ier = serial8250_early_in(port, UART_IER);
> - if (ier)
> - serial8250_early_out(port, UART_IER, ier & UART_IER_UUE);
>
> uart_console_write(port, s, count, serial_putc);



> -
> - /* Wait for transmitter to become empty and restore the IER */
> - wait_for_xmitr(port);

This wait_for_xmitr() change needs to be in patch 2/2.

Regards,
Peter Hurley

> -
> - if (ier)
> - serial8250_early_out(port, UART_IER, ier);
> }
>
> static void __init init_port(struct earlycon_device *device)
>

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