Re: [PATCH v1] m68k: apollo: Remove a duplicate assignment in dn_timer_int

Geert Uytterhoeven
2023-07-05T12:39:06Z

Hi Minjie,

On Wed, Jul 5, 2023 at 2:13 PM Minjie Du <duminjie@vivo.com> wrote:
> Delete a duplicate statement from this function implementation.
>
> Signed-off-by: Minjie Du <duminjie@vivo.com>

Thanks for your patch, which is presumably untested on real hardware?

> --- a/arch/m68k/apollo/config.c
> +++ b/arch/m68k/apollo/config.c
> @@ -173,7 +173,6 @@ irqreturn_t dn_timer_int(int irq, void *dev_id)
> legacy_timer_tick(1);
> timer_heartbeat();
>
> - x = *(volatile unsigned char *)(apollo_timer + 3);
> x = *(volatile unsigned char *)(apollo_timer + 5);

This is intentional: the use of volatile makes sure the registers at
offsets 3 and 5 are read, in that order.

I agree this could be made more obvious by converting the code to the
more modern READ_ONCE() helper.
But please do not send such a patch without testing.

>
> return IRQ_HANDLED;

NAKed-by: Geert Uytterhoeven <geert@linux-m68k.org>

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds