Subject: Re: [PATCH] serial: Use real irq on UART0 (IRQ = 0) on PPC4xx systems

From: Sergei Shtylyov <[email-masked]>
Date: Mon, 20 Nov 2006 16:28:03 +0300

Hello.

Stefan Roese wrote:
> This patch fixes a problem seen on multiple 4xx platforms, where
> the UART0 interrupt number is 0. The macro "is_real_interrupt" lead
> on those systems to not use an real interrupt but the timer based
> implementation.

> This problem was detected and fixed by
> Charles Gales <[email-masked]> and John Baxter <[email-masked]>
> from AMCC.

> Signed-off-by: Stefan Roese <[email-masked]>

> ---
> commit f83094acd3258575c9a5cdb1d65e241c16eff03a
> tree 72582c5eeb2a9c8ea57287616d51e42fff8ed641
> parent f56f68c4e1977f0e884a304af4c617bed4909417
> author Stefan Roese <[email-masked]> Sat, 18 Nov 2006 10:28:50 +0100
> committer Stefan Roese <[email-masked]> Sat, 18 Nov 2006 10:28:50 +0100

>  drivers/serial/8250.c |   22 ++++++++++++++--------
>  1 files changed, 14 insertions(+), 8 deletions(-)

> diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
> index e34bd03..a51679e 100644
> --- a/drivers/serial/8250.c
> +++ b/drivers/serial/8250.c
> @@ -76,8 +76,14 @@ static unsigned int nr_uarts = CONFIG_SE
>   * We default to IRQ0 for the "no irq" hack.   Some
>   * machine types want others as well - they're free
>   * to redefine this in their header file.
> + * NOTE:  Some PPC4xx use IRQ0 for a UART Interrupt, so
> + * we will assume that the IRQ is always real
>   */
> +#ifdef CONFIG_4xx
> +#define is_real_interrupt(irq)	(1)
> +#else
>  #define is_real_interrupt(irq)	((irq) != 0)
> +#endif

    This should have been done in <asm/serial.h> instead, like this:

#undef is_real_interrupt(irq)
#define is_real_interrupt(irq)	1

    Not too smart as well,but at least this wasy you won't be pulluting the 
generic code...

WBR, Sergei