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From:   Andreas Schwab <schwab@linux-m68k.org>
To:     Mathieu Malaterre <malat@debian.org>
Cc:     Arnd Bergmann <arnd@arndb.de>, Paul Mackerras <paulus@samba.org>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Geert Uytterhoeven <geert@linux-m68k.org>, funaho@jurai.org,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        gerg@linux-m68k.org, linux-m68k@lists.linux-m68k.org,
        linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
        LKML <linux-kernel@vger.kernel.org>, y2038@lists.linaro.org,
        Meelis Roos <mroos@linux.ee>,
        Alexandre Belloni <alexandre.belloni@free-electrons.com>
Subject: Re: [PATCH 1/3] powerpc: mac: fix rtc read functions
References: <20180618140518.2920804-1-arnd@arndb.de>
        <CA+7wUswcgxLz_GAqkyVLpdAmTNEPUZ-cXJ8Ej7Xx9+OgjGUo=Q@mail.gmail.com>
Date:   Mon, 18 Jun 2018 22:04:49 +0200
In-Reply-To: <CA+7wUswcgxLz_GAqkyVLpdAmTNEPUZ-cXJ8Ej7Xx9+OgjGUo=Q@mail.gmail.com>
        (Mathieu Malaterre's message of "Mon, 18 Jun 2018 21:10:06 +0200")
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On Jun 18 2018, Mathieu Malaterre <malat@debian.org> wrote:

> Sadly, trying again today does not work anymore. Adding some printk
> just before WARN_ON:
>
> +printk(KERN_ERR " rtc DBG pmu_get_time1: %lld %d %lld \n", now,
> RTC_OFFSET, now - RTC_OFFSET );
> +printk(KERN_ERR " rtc DBG pmu_get_time2: %x %x %x %x %d \n",
> req.reply[0], req.reply[1], req.reply[2], req.reply[3] ,
> req.reply_len);
>
> leads to:
>
> [    0.000000]  rtc DBG pmu_get_time1: 14096662 2082844800 -2068748138
> [    0.000000]  rtc DBG pmu_get_time2: 0 d7 19 16 4

A good value would have 0xd7 in the first byte.  The problem is that
pmu_set_rtc_time is also broken, and leads to an invalid time value
stored in the RTC.  Since pmu_request is a varargs function passing
values of type time64_t without casting won't work.

You need to reset your RTC before you can continue.

I think the right fix is to change nowtime in pmu_set_rtc_time and
cuda_set_rtc_time back to unsigned int (or to u32).

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510  2552 DF73 E780 A9DA AEC1
"And now for something completely different."