linux-kernel - Re: [PATCH 1/2] platform/chrome: Add CrOS USB PD logging driver

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Date:   Fri, 5 Apr 2019 23:09:27 +0200
From:   Enric Balletbo Serra <eballetbo@...il.com>
To:     Guenter Roeck <groeck@...gle.com>
Cc:     Enric Balletbo i Serra <enric.balletbo@...labora.com>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Gwendal Grignou <gwendal@...omium.org>, jflat@...omium.org,
        kernel@...labora.com, Lee Jones <lee.jones@...aro.org>,
        Benson Leung <bleung@...omium.org>,
        Guenter Roeck <groeck@...omium.org>,
        Rajat Jain <rajatja@...gle.com>,
        Dmitry Torokhov <dtor@...omium.org>
Subject: Re: [PATCH 1/2] platform/chrome: Add CrOS USB PD logging driver

Hi Guenter,

Missatge de Guenter Roeck <groeck@...gle.com> del dia dv., 5 d’abr.
2019 a les 21:59:
>
> Hi Enric,
>
> On Wed, Apr 3, 2019 at 6:54 AM Enric Balletbo i Serra
> <enric.balletbo@...labora.com> wrote:
> >
> > From: Guenter Roeck <groeck@...omium.org>
> >
> > The CrOS USB PD logging feature is logically separate functionality of
> > the charge manager, hence has its own driver. The driver logs the event
> > data for the USB PD charger available in some ChromeOS Embedded
> > Controllers.
> >
> > Signed-off-by: Guenter Roeck <groeck@...omium.org>
> > [remove APPEND_STRING macro and minor cleanups]
> > Signed-off-by: Enric Balletbo i Serra <enric.balletbo@...labora.com>
> > ---
> >
> [ ... ]
>
> > +
> > +static void cros_usbpd_print_log_entry(struct ec_response_pd_log *r,
> > +                                      ktime_t tstamp)
> > +{
> [ ... ]
> > +
> > +       pr_info("PDLOG %d/%02d/%02d %02d:%02d:%02d.%03lld P%d %s\n",
> > +               rt.tm_year + 1900, rt.tm_mon + 1, rt.tm_mday,
> > +               rt.tm_hour, rt.tm_min, rt.tm_sec,
> > +               ktime_to_ms(tstamp) % MSEC_PER_SEC,
>
> 0day rightfully complains that this introduces a 64-bit divide
> operation. I don't know if do_div() works here since it tries to
> modify the first parameter. Maybe we need an interim variable to store
> ktime_to_ms(tstamp). Something like
>
>     s64 temp = ktime_to_ms(tstamp);
>     ...
>                     do_div(temp, MSEC_PER_SEC),
>

I did something similar this afternoon and pushed again for the auto
builders to play with.

+ div_s64_rem(ktime_to_ms(tstamp), MSEC_PER_SEC, &rem);

Unfortunately, 0day now reports another error

drivers/platform/chrome/cros_usbpd_logger.o: In function
`cros_usbpd_print_log_entry':
>> cros_usbpd_logger.c:(.text+0x5a0): undefined reference to `__aeabi_ldivmod'

I'll investigate in more detail Monday morning.

Thanks
- Enric

> Guenter