svn commit: r335156 - head/sys/arm/arm

[Emmanuel Vadot]

On Thu, 14 Jun 2018 12:26:38 -0500
Kyle Evans <kevans at freebsd.org> wrote:

> On Thu, Jun 14, 2018 at 12:18 PM, Emmanuel Vadot <manu at freebsd.org> wrote:
> > Author: manu
> > Date: Thu Jun 14 17:18:15 2018
> > New Revision: 335156
> > URL: https://svnweb.freebsd.org/changeset/base/335156
> >
> > Log:
> >   arm timer: Add workaround for Allwinner A64 timer
> >
> >   The timer present in allwinner A64 SoC is unstable, value can jump backward
> >   or forward.
> >   It was found that when bit 11 and upper roll over the low bits can sometimes
> >   being read as all as 1 or all as 0.
> >   Simply ignore the values for those cases.
> >
> > Modified:
> >   head/sys/arm/arm/generic_timer.c
> >
> > Modified: head/sys/arm/arm/generic_timer.c
> > ==============================================================================
> > --- head/sys/arm/arm/generic_timer.c    Thu Jun 14 17:09:33 2018        (r335155)
> > +++ head/sys/arm/arm/generic_timer.c    Thu Jun 14 17:18:15 2018        (r335156)
> > @@ -92,6 +92,7 @@ __FBSDID("$FreeBSD$");
> >  struct arm_tmr_softc {
> >         struct resource         *res[4];
> >         void                    *ihl[4];
> > +       uint64_t                (*get_cntxct)(bool);
> >         uint32_t                clkfreq;
> >         struct eventtimer       et;
> >         bool                    physical;
> > @@ -142,6 +143,28 @@ get_freq(void)
> >  }
> >
> >  static uint64_t
> > +get_cntxct_a64_unstable(bool physical)
> > +{
> > +       uint64_t val
> > +;
> > +       isb();
> > +       if (physical) {
> > +               do {
> > +                       val = get_el0(cntpct);
> > +               }
> > +               while (((val + 1) & 0x7FF) <= 1);
> > +       }
> > +       else {
> > +               do {
> > +                       val = get_el0(cntvct);
> > +               }
> > +               while (((val + 1) & 0x7FF) <= 1);
> > +       }
> > +
> > +       return (val);
> > +}
> > +
> > +static uint64_t
> >  get_cntxct(bool physical)
> >  {
> >         uint64_t val;
> > @@ -226,7 +249,7 @@ static unsigned
> >  arm_tmr_get_timecount(struct timecounter *tc)
> >  {
> >
> > -       return (get_cntxct(arm_tmr_sc->physical));
> > +       return (arm_tmr_sc->get_cntxct(arm_tmr_sc->physical));
> >  }
> >
> >  static int
> > @@ -379,6 +402,7 @@ arm_tmr_attach(device_t dev)
> >         if (arm_tmr_sc)
> >                 return (ENXIO);
> >
> > +       sc->get_cntxct = &get_cntxct_a64_unstable;
> >  #ifdef FDT
> >         /* Get the base clock frequency */
> >         node = ofw_bus_get_node(dev);
> 
> Was it intentional to set sc->get_cntxct to get_cntxct_a64_unstable in
> the general case? Seems like this should've been get_cntxct.

 Fixed in 335161.
 Thanks,

> > @@ -387,6 +411,13 @@ arm_tmr_attach(device_t dev)
> >                     sizeof(clock));
> >                 if (error > 0)
> >                         sc->clkfreq = clock;
> > +
> > +               if (OF_hasprop(node, "allwinner,sun50i-a64-unstable-timer")) {
> > +                       sc->get_cntxct = &get_cntxct_a64_unstable;
> > +                       if (bootverbose)
> > +                               device_printf(dev,
> > +                                   "Enabling allwinner unstable timer workaround\n");
> > +               }
> >         }
> >  #endif
> >
> 
> Since the a64-specific get_cntxct is set here.
> 
> > @@ -518,10 +549,10 @@ arm_tmr_do_delay(int usec, void *arg)
> >         else
> >                 counts = usec * counts_per_usec;
> >
> > -       first = get_cntxct(sc->physical);
> > +       first = sc->get_cntxct(sc->physical);
> >
> >         while (counts > 0) {
> > -               last = get_cntxct(sc->physical);
> > +               last = sc->get_cntxct(sc->physical);
> >                 counts -= (int32_t)(last - first);
> >                 first = last;
> >         }
> > _______________________________________________
> > svn-src-head at freebsd.org mailing list
> > https://lists.freebsd.org/mailman/listinfo/svn-src-head
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-- 
Emmanuel Vadot <manu at bidouilliste.com> <manu at freebsd.org>