Date: Thu, 14 Jun 2018 12:26:38 -0500 From: Kyle Evans <kevans@freebsd.org> To: Emmanuel Vadot <manu@freebsd.org> Cc: src-committers <src-committers@freebsd.org>, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r335156 - head/sys/arm/arm Message-ID: <CACNAnaHP1p_rHo4j_-=durF_E99mWh-U2=azZUML5ksJjRbWTQ@mail.gmail.com> In-Reply-To: <201806141718.w5EHIFnE093607@repo.freebsd.org> References: <201806141718.w5EHIFnE093607@repo.freebsd.org>
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On Thu, Jun 14, 2018 at 12:18 PM, Emmanuel Vadot <manu@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@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/svn-src-head > To unsubscribe, send any mail to "svn-src-head-unsubscribe@freebsd.org"
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