LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Boris Brezillon <boris.brezillon@bootlin.com>
Cc: linux-m68k <linux-m68k@vger.kernel.org>,
	David Woodhouse <dwmw2@infradead.org>,
	Brian Norris <computersforpeace@gmail.com>,
	Marek Vasut <marek.vasut@gmail.com>,
	Richard Weinberger <richard@nod.at>,
	MTD Maling List <linux-mtd@lists.infradead.org>,
	Miquel Raynal <miquel.raynal@bootlin.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Michael Schmitz <schmitzmic@gmail.com>
Subject: Re: [PATCH] m68k: Implement ndelay() as an inline function to force type checking/casting
Date: Mon, 14 May 2018 11:29:57 +0200	[thread overview]
Message-ID: <CAMuHMdVdteVYjXkmZW+PouVsvPehT_GMfvEKo7OKqs4XYdiSpA@mail.gmail.com> (raw)
In-Reply-To: <20180513140212.3961-1-boris.brezillon@bootlin.com>

Hi Boris,

On Sun, May 13, 2018 at 4:02 PM, Boris Brezillon
<boris.brezillon@bootlin.com> wrote:
> ndelay() is supposed to take an unsigned long, but if you define
> ndelay() as a macro and the caller pass an unsigned long long instead
> of an unsigned long, the unsigned long long to unsigned long cast is
> not done and we end up with an "undefined reference to `__udivdi3'"
> error at link time.
>
> Fix that by making ndelay() an inline function and then defining dummy
> ndelay() macro that redirects to the ndelay() function (it's how most
> archs do to implement ndelay()).
>
> Fixes: c8ee038bd148 ("m68k: Implement ndelay() based on the existing udelay() logic")
> Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
> ---
> Hello Geert,
>
> This patch is fixing the bug reported by kbuild test robot here [1].
> I could have patched the PSEC_TO_NSEC() macro to cast the result of
> the division on a u32, but I thought making m68k consistent with what
> other archs do would be preferable.
>
> Let me know if don't like the solution, and I'll patch the ndelay()
> caller instead.

Thanks for your patch!

With the comment a few lines above removed:

    - * This is a macro so that the const version can factor out the first
    - * multiply and shift.

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

>
> Regards,
>
> Boris
>
> [1]https://lkml.org/lkml/2018/5/13/72
> ---
>  arch/m68k/include/asm/delay.h | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/arch/m68k/include/asm/delay.h b/arch/m68k/include/asm/delay.h
> index 7f474121e4ca..66ba159002a3 100644
> --- a/arch/m68k/include/asm/delay.h
> +++ b/arch/m68k/include/asm/delay.h
> @@ -115,6 +115,13 @@ static inline void __udelay(unsigned long usecs)
>   */
>  #define        HZSCALE         (268435456 / (1000000 / HZ))
>
> -#define ndelay(n) __delay(DIV_ROUND_UP((n) * ((((HZSCALE) >> 11) * (loops_per_jiffy >> 11)) >> 6), 1000))
> +static inline void ndelay(unsigned long nsec)
> +{
> +       __delay(DIV_ROUND_UP(nsec *
> +                            ((((HZSCALE) >> 11) *
> +                              (loops_per_jiffy >> 11)) >> 6),
> +                            1000));
> +}
> +#define ndelay(n) ndelay(n)
>
>  #endif /* defined(_M68K_DELAY_H) */

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

  parent reply	other threads:[~2018-05-14  9:30 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-13 14:02 Boris Brezillon
2018-05-13 22:38 ` Andy Shevchenko
2018-05-14  7:23 ` Miquel Raynal
2018-05-14  9:29 ` Geert Uytterhoeven [this message]
2018-05-14 10:52   ` Geert Uytterhoeven

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=CAMuHMdVdteVYjXkmZW+PouVsvPehT_GMfvEKo7OKqs4XYdiSpA@mail.gmail.com \
    --to=geert@linux-m68k.org \
    --cc=boris.brezillon@bootlin.com \
    --cc=computersforpeace@gmail.com \
    --cc=dwmw2@infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-m68k@vger.kernel.org \
    --cc=linux-mtd@lists.infradead.org \
    --cc=marek.vasut@gmail.com \
    --cc=miquel.raynal@bootlin.com \
    --cc=richard@nod.at \
    --cc=schmitzmic@gmail.com \
    --subject='Re: [PATCH] m68k: Implement ndelay() as an inline function to force type checking/casting' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).