On 10/22/2015 04:21 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.
>
> Let wait_for_xmitr() melt into serial_putc().
Both of these changes are ok with me, but please split this into
2 patches so reverting either one in case of regression is trivial.
Regards,
Peter Hurley
> Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
> ---
>
> drivers/tty/serial/8250/8250_early.c | 20 ++------------------
> 1 file changed, 2 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/tty/serial/8250/8250_early.c b/drivers/tty/serial/8250/8250_early.c
> index 7aff3d8..19aca19 100644
> --- a/drivers/tty/serial/8250/8250_early.c
> +++ b/drivers/tty/serial/8250/8250_early.c
> @@ -76,21 +76,17 @@ static void __init serial8250_early_out(struct uart_port *port, int offset, int
>
> #define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)
>
> -static void __init wait_for_xmitr(struct uart_port *port)
> +static void __init serial_putc(struct uart_port *port, int c)
> {
> unsigned int status;
>
> for (;;) {
> status = serial8250_early_in(port, UART_LSR);
> if ((status & BOTH_EMPTY) == BOTH_EMPTY)
> - return;
> + break;
> cpu_relax();
> }
> -}
>
> -static void __init serial_putc(struct uart_port *port, int c)
> -{
> - wait_for_xmitr(port);
> serial8250_early_out(port, UART_TX, c);
> }
>
> @@ -99,20 +95,8 @@ 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);
> -
> - if (ier)
> - serial8250_early_out(port, UART_IER, ier);
> }
>
> static void __init init_port(struct earlycon_device *device)
>
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