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authorLinus Torvalds <torvalds@linux-foundation.org>2011-03-15 20:01:36 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-03-15 20:01:36 -0700
commitd10902812c9cd5583130a4ebb9ad19c60b68149d (patch)
treeb1b28587970e8cebf74ba4d61edf49537f619ab7 /arch/x86/kernel/apb_timer.c
parent181f977d134a9f8e3f8839f42af655b045fc059e (diff)
parent25874a299ef8037df03ce4ada570bc4e42f9748f (diff)
downloadtalos-op-linux-d10902812c9cd5583130a4ebb9ad19c60b68149d.tar.gz
talos-op-linux-d10902812c9cd5583130a4ebb9ad19c60b68149d.zip
Merge branch 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (27 commits) x86: Clean up apic.c and apic.h x86: Remove superflous goal definition of tsc_sync x86: dt: Correct local apic documentation in device tree bindings x86: dt: Cleanup local apic setup x86: dt: Fix OLPC=y/INTEL_CE=n build rtc: cmos: Add OF bindings x86: ce4100: Use OF to setup devices x86: ioapic: Add OF bindings for IO_APIC x86: dtb: Add generic bus probe x86: dtb: Add support for PCI devices backed by dtb nodes x86: dtb: Add device tree support for HPET x86: dtb: Add early parsing of IO_APIC x86: dtb: Add irq domain abstraction x86: dtb: Add a device tree for CE4100 x86: Add device tree support x86: e820: Remove conditional early mapping in parse_e820_ext x86: OLPC: Make OLPC=n build again x86: OLPC: Remove extra OLPC_OPENFIRMWARE_DT indirection x86: OLPC: Cleanup config maze completely x86: OLPC: Hide OLPC_OPENFIRMWARE config switch ... Fix up conflicts in arch/x86/platform/ce4100/ce4100.c
Diffstat (limited to 'arch/x86/kernel/apb_timer.c')
-rw-r--r--arch/x86/kernel/apb_timer.c60
1 files changed, 4 insertions, 56 deletions
diff --git a/arch/x86/kernel/apb_timer.c b/arch/x86/kernel/apb_timer.c
index 51d4e1663066..1293c709ee85 100644
--- a/arch/x86/kernel/apb_timer.c
+++ b/arch/x86/kernel/apb_timer.c
@@ -508,64 +508,12 @@ static int apbt_next_event(unsigned long delta,
return 0;
}
-/*
- * APB timer clock is not in sync with pclk on Langwell, which translates to
- * unreliable read value caused by sampling error. the error does not add up
- * overtime and only happens when sampling a 0 as a 1 by mistake. so the time
- * would go backwards. the following code is trying to prevent time traveling
- * backwards. little bit paranoid.
- */
static cycle_t apbt_read_clocksource(struct clocksource *cs)
{
- unsigned long t0, t1, t2;
- static unsigned long last_read;
-
-bad_count:
- t1 = apbt_readl(phy_cs_timer_id,
- APBTMR_N_CURRENT_VALUE);
- t2 = apbt_readl(phy_cs_timer_id,
- APBTMR_N_CURRENT_VALUE);
- if (unlikely(t1 < t2)) {
- pr_debug("APBT: read current count error %lx:%lx:%lx\n",
- t1, t2, t2 - t1);
- goto bad_count;
- }
- /*
- * check against cached last read, makes sure time does not go back.
- * it could be a normal rollover but we will do tripple check anyway
- */
- if (unlikely(t2 > last_read)) {
- /* check if we have a normal rollover */
- unsigned long raw_intr_status =
- apbt_readl_reg(APBTMRS_RAW_INT_STATUS);
- /*
- * cs timer interrupt is masked but raw intr bit is set if
- * rollover occurs. then we read EOI reg to clear it.
- */
- if (raw_intr_status & (1 << phy_cs_timer_id)) {
- apbt_readl(phy_cs_timer_id, APBTMR_N_EOI);
- goto out;
- }
- pr_debug("APB CS going back %lx:%lx:%lx ",
- t2, last_read, t2 - last_read);
-bad_count_x3:
- pr_debug("triple check enforced\n");
- t0 = apbt_readl(phy_cs_timer_id,
- APBTMR_N_CURRENT_VALUE);
- udelay(1);
- t1 = apbt_readl(phy_cs_timer_id,
- APBTMR_N_CURRENT_VALUE);
- udelay(1);
- t2 = apbt_readl(phy_cs_timer_id,
- APBTMR_N_CURRENT_VALUE);
- if ((t2 > t1) || (t1 > t0)) {
- printk(KERN_ERR "Error: APB CS tripple check failed\n");
- goto bad_count_x3;
- }
- }
-out:
- last_read = t2;
- return (cycle_t)~t2;
+ unsigned long current_count;
+
+ current_count = apbt_readl(phy_cs_timer_id, APBTMR_N_CURRENT_VALUE);
+ return (cycle_t)~current_count;
}
static int apbt_clocksource_register(void)
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