[U-Boot] [PATCH] ns16550: Add WATCHDOG_RESET to putc for short watchdog timeout boards

[Wolfgang Denk]

Dear Stefan Roese,

In message <1285773233-29381-1-git-send-email-sr at denx.de> you wrote:
> This is needed for board with a very short watchdog timeout, like the
> lwmon5 with a 100ms timeout. Without this patch this board resets in the
> commands with long outputs, like "printenv" or "fdt print".
> 
> Note that the image size is not increased with this patch when
> CONFIG_HW_WATCHDOG or CONFIG_WATCHDOG are not defined since the compiler
> optimizes this additional code away.
> 
> Signed-off-by: Stefan Roese <sr at denx.de>
> ---
>  drivers/serial/ns16550.c |    9 ++++++++-
>  1 files changed, 8 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/serial/ns16550.c b/drivers/serial/ns16550.c
> index 7e833fd..25fa521 100644
> --- a/drivers/serial/ns16550.c
> +++ b/drivers/serial/ns16550.c
> @@ -5,6 +5,7 @@
>   */
>  
>  #include <config.h>
> +#include <common.h>
>  #include <ns16550.h>
>  #include <watchdog.h>
>  #include <linux/types.h>
> @@ -68,7 +69,13 @@ void NS16550_reinit (NS16550_t com_port, int baud_divisor)
>  
>  void NS16550_putc (NS16550_t com_port, char c)
>  {
> -	while ((serial_in(&com_port->lsr) & UART_LSR_THRE) == 0);
> +	while ((serial_in(&com_port->lsr) & UART_LSR_THRE) == 0) {
> +		int count = 0;
> +
> +		/* reset watchdog from time to time */
> +		if ((count++ % (256 << 10)) == 0)
> +			WATCHDOG_RESET();
> +	}

This code makes no sense to me. You initialize the variable in the
same loop, so it will never bi different from 0 when you test it.

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
Severe culture shock results when experts from another protocol suite
[...] try to read OSI documents. The term "osified" is used to  refer
to  such  documents. [...] Any relationship to the word "ossified" is
purely intentional.                                - Marshall T. Rose