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From:   Geert Uytterhoeven <geert@linux-m68k.org>
Date:   Fri, 13 May 2022 09:12:28 +0200
Message-ID: <CAMuHMdVWRM7U9_SxbtDUE0a-sB5_PDiO2009Cu3QKMP3wNc=yw@mail.gmail.com>
Subject: Re: [PATCH] m68knommu: fix undefined reference to `mach_get_rtc_pll'
To:     Greg Ungerer <gerg@linux-m68k.org>
Cc:     "Linux/m68k" <linux-m68k@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Arnd Bergmann <arnd@arndb.de>,
        kernel test robot <lkp@intel.com>
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Hi Greg,

On Fri, May 13, 2022 at 8:50 AM Greg Ungerer <gerg@linux-m68k.org> wrote:
> Configuring for a nommu classic m68k target and enabling the generic rtc
> driver (CONFIG_RTC_DRV_GENERIC) will result in the following compile
> error:
>
>    m68k-linux-ld: arch/m68k/kernel/time.o: in function `rtc_ioctl':
>    time.c:(.text+0x82): undefined reference to `mach_get_rtc_pll'
>    m68k-linux-ld: time.c:(.text+0xbc): undefined reference to `mach_set_rtc_pll'
>    m68k-linux-ld: time.c:(.text+0xf4): undefined reference to `mach_set_rtc_pll'
>
> "mach_set_rtc_pll" and "mach_get_rtc_pll" are only defined in the common
> MMU setup code, and are really only implemented in any meaningful way on
> classic M68K MMU enabled machines. So conditionally limit their use to

And only on Q40/Q60.

> MMU enabled classic M68K systems.
>
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>

Thanks for your patch!

> --- a/arch/m68k/kernel/time.c
> +++ b/arch/m68k/kernel/time.c
> @@ -62,7 +62,7 @@ void timer_heartbeat(void)
>  }
>  #endif /* CONFIG_HEARTBEAT */
>
> -#ifdef CONFIG_M68KCLASSIC
> +#if defined(CONFIG_M68KCLASSIC) && defined(CONFIG_MMU)
>  #if !IS_BUILTIN(CONFIG_RTC_DRV_GENERIC)
>  void read_persistent_clock64(struct timespec64 *ts)
>  {

read_persistent_clock64() uses mach_hwclk(), which is provided by
both setup_mm.c and setup_no.c, so it's always available?
Albeit not populated by coldfire or nommu platform code, so I see
the point in depending on MMU (no nommu Amiga support yet ;-).

Perhaps rtc_ioctl() should depend on CONFIG_Q40?

> @@ -140,7 +140,7 @@ static int __init rtc_init(void)
>
>  module_init(rtc_init);
>  #endif /* CONFIG_RTC_DRV_GENERIC */
> -#endif /* CONFIG M68KCLASSIC */
> +#endif /* CONFIG M68KCLASSIC && CONFIG_MMU */
>
>  void __init time_init(void)
>  {

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