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authorLinus Torvalds <torvalds@linux-foundation.org>2009-09-18 14:05:47 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-09-18 14:05:47 -0700
commit78f28b7c555359c67c2a0d23f7436e915329421e (patch)
tree7f8197f82f83c0c19fd9bc85b5d10b5a755d0656 /arch/x86/kernel/tsc.c
parent3240a77b515f4a15e24d8a3a2135bc87b02cf1d6 (diff)
parent7bd867dfb4e0357e06a3211ab2bd0e714110def3 (diff)
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: (38 commits) x86: Move get/set_wallclock to x86_platform_ops x86: platform: Fix section annotations x86: apic namespace cleanup x86: Distangle ioapic and i8259 x86: Add Moorestown early detection x86: Add hardware_subarch ID for Moorestown x86: Add early platform detection x86: Move tsc_init to late_time_init x86: Move tsc_calibration to x86_init_ops x86: Replace the now identical time_32/64.c by time.c x86: time_32/64.c unify profile_pc x86: Move calibrate_cpu to tsc.c x86: Make timer setup and global variables the same in time_32/64.c x86: Remove mca bus ifdef from timer interrupt x86: Simplify timer_ack magic in time_32.c x86: Prepare unification of time_32/64.c x86: Remove do_timer hook x86: Add timer_init to x86_init_ops x86: Move percpu clockevents setup to x86_init_ops x86: Move xen_post_allocator_init into xen_pagetable_setup_done ... Fix up conflicts in arch/x86/include/asm/io_apic.h
Diffstat (limited to 'arch/x86/kernel/tsc.c')
-rw-r--r--arch/x86/kernel/tsc.c72
1 files changed, 61 insertions, 11 deletions
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index fc3672a303d6..17409e8d1097 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -17,6 +17,8 @@
#include <asm/time.h>
#include <asm/delay.h>
#include <asm/hypervisor.h>
+#include <asm/nmi.h>
+#include <asm/x86_init.h>
unsigned int __read_mostly cpu_khz; /* TSC clocks / usec, not used here */
EXPORT_SYMBOL(cpu_khz);
@@ -400,15 +402,9 @@ unsigned long native_calibrate_tsc(void)
{
u64 tsc1, tsc2, delta, ref1, ref2;
unsigned long tsc_pit_min = ULONG_MAX, tsc_ref_min = ULONG_MAX;
- unsigned long flags, latch, ms, fast_calibrate, hv_tsc_khz;
+ unsigned long flags, latch, ms, fast_calibrate;
int hpet = is_hpet_enabled(), i, loopmin;
- hv_tsc_khz = get_hypervisor_tsc_freq();
- if (hv_tsc_khz) {
- printk(KERN_INFO "TSC: Frequency read from the hypervisor\n");
- return hv_tsc_khz;
- }
-
local_irq_save(flags);
fast_calibrate = quick_pit_calibrate();
local_irq_restore(flags);
@@ -566,7 +562,7 @@ int recalibrate_cpu_khz(void)
unsigned long cpu_khz_old = cpu_khz;
if (cpu_has_tsc) {
- tsc_khz = calibrate_tsc();
+ tsc_khz = x86_platform.calibrate_tsc();
cpu_khz = tsc_khz;
cpu_data(0).loops_per_jiffy =
cpufreq_scale(cpu_data(0).loops_per_jiffy,
@@ -860,15 +856,71 @@ static void __init init_tsc_clocksource(void)
clocksource_register(&clocksource_tsc);
}
+#ifdef CONFIG_X86_64
+/*
+ * calibrate_cpu is used on systems with fixed rate TSCs to determine
+ * processor frequency
+ */
+#define TICK_COUNT 100000000
+static unsigned long __init calibrate_cpu(void)
+{
+ int tsc_start, tsc_now;
+ int i, no_ctr_free;
+ unsigned long evntsel3 = 0, pmc3 = 0, pmc_now = 0;
+ unsigned long flags;
+
+ for (i = 0; i < 4; i++)
+ if (avail_to_resrv_perfctr_nmi_bit(i))
+ break;
+ no_ctr_free = (i == 4);
+ if (no_ctr_free) {
+ WARN(1, KERN_WARNING "Warning: AMD perfctrs busy ... "
+ "cpu_khz value may be incorrect.\n");
+ i = 3;
+ rdmsrl(MSR_K7_EVNTSEL3, evntsel3);
+ wrmsrl(MSR_K7_EVNTSEL3, 0);
+ rdmsrl(MSR_K7_PERFCTR3, pmc3);
+ } else {
+ reserve_perfctr_nmi(MSR_K7_PERFCTR0 + i);
+ reserve_evntsel_nmi(MSR_K7_EVNTSEL0 + i);
+ }
+ local_irq_save(flags);
+ /* start measuring cycles, incrementing from 0 */
+ wrmsrl(MSR_K7_PERFCTR0 + i, 0);
+ wrmsrl(MSR_K7_EVNTSEL0 + i, 1 << 22 | 3 << 16 | 0x76);
+ rdtscl(tsc_start);
+ do {
+ rdmsrl(MSR_K7_PERFCTR0 + i, pmc_now);
+ tsc_now = get_cycles();
+ } while ((tsc_now - tsc_start) < TICK_COUNT);
+
+ local_irq_restore(flags);
+ if (no_ctr_free) {
+ wrmsrl(MSR_K7_EVNTSEL3, 0);
+ wrmsrl(MSR_K7_PERFCTR3, pmc3);
+ wrmsrl(MSR_K7_EVNTSEL3, evntsel3);
+ } else {
+ release_perfctr_nmi(MSR_K7_PERFCTR0 + i);
+ release_evntsel_nmi(MSR_K7_EVNTSEL0 + i);
+ }
+
+ return pmc_now * tsc_khz / (tsc_now - tsc_start);
+}
+#else
+static inline unsigned long calibrate_cpu(void) { return cpu_khz; }
+#endif
+
void __init tsc_init(void)
{
u64 lpj;
int cpu;
+ x86_init.timers.tsc_pre_init();
+
if (!cpu_has_tsc)
return;
- tsc_khz = calibrate_tsc();
+ tsc_khz = x86_platform.calibrate_tsc();
cpu_khz = tsc_khz;
if (!tsc_khz) {
@@ -876,11 +928,9 @@ void __init tsc_init(void)
return;
}
-#ifdef CONFIG_X86_64
if (cpu_has(&boot_cpu_data, X86_FEATURE_CONSTANT_TSC) &&
(boot_cpu_data.x86_vendor == X86_VENDOR_AMD))
cpu_khz = calibrate_cpu();
-#endif
printk("Detected %lu.%03lu MHz processor.\n",
(unsigned long)cpu_khz / 1000,