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

[Kyle Evans]

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.

> @@ -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
> To unsubscribe, send any mail to "svn-src-head-unsubscribe at freebsd.org"