diff options
| -rw-r--r-- | Documentation/x86_64/boot-options.txt | 5 | ||||
| -rw-r--r-- | arch/x86_64/kernel/apic.c | 33 | ||||
| -rw-r--r-- | arch/x86_64/kernel/pmtimer.c | 20 | ||||
| -rw-r--r-- | include/asm-x86_64/proto.h | 1 |
4 files changed, 53 insertions, 6 deletions
diff --git a/Documentation/x86_64/boot-options.txt b/Documentation/x86_64/boot-options.txt index 654ea4fccff88..153740f460a6c 100644 --- a/Documentation/x86_64/boot-options.txt +++ b/Documentation/x86_64/boot-options.txt @@ -47,6 +47,11 @@ APICs noapicmaintimer Don't do time keeping using the APIC timer. Useful when this option was auto selected, but doesn't work. + apicpmtimer + Do APIC timer calibration using the pmtimer. Implies + apicmaintimer. Useful when your PIT timer is totally + broken. + Early Console syntax: earlyprintk=vga diff --git a/arch/x86_64/kernel/apic.c b/arch/x86_64/kernel/apic.c index 673a2fe9923cb..c02218b3ae2b2 100644 --- a/arch/x86_64/kernel/apic.c +++ b/arch/x86_64/kernel/apic.c @@ -40,6 +40,7 @@ int apic_verbosity; int apic_runs_main_timer; +int apic_calibrate_pmtmr __initdata; int disable_apic_timer __initdata; @@ -746,14 +747,27 @@ static int __init calibrate_APIC_clock(void) __setup_APIC_LVTT(1000000000); apic_start = apic_read(APIC_TMCCT); - rdtscl(tsc_start); - - do { +#ifdef CONFIG_X86_PM_TIMER + if (apic_calibrate_pmtmr && pmtmr_ioport) { + pmtimer_wait(5000); /* 5ms wait */ apic = apic_read(APIC_TMCCT); - rdtscl(tsc); - } while ((tsc - tsc_start) < TICK_COUNT && (apic - apic_start) < TICK_COUNT); + result = (apic_start - apic) * 1000L / 5; + } else +#endif + { + rdtscl(tsc_start); + + do { + apic = apic_read(APIC_TMCCT); + rdtscl(tsc); + } while ((tsc - tsc_start) < TICK_COUNT && + (apic - apic_start) < TICK_COUNT); + + result = (apic_start - apic) * 1000L * cpu_khz / + (tsc - tsc_start); + } + printk("result %d\n", result); - result = (apic_start - apic) * 1000L * cpu_khz / (tsc - tsc_start); printk(KERN_INFO "Detected %d.%03d MHz APIC timer.\n", result / 1000 / 1000, result / 1000 % 1000); @@ -1115,6 +1129,13 @@ static __init int setup_noapicmaintimer(char *str) } __setup("noapicmaintimer", setup_noapicmaintimer); +static __init int setup_apicpmtimer(char *s) +{ + apic_calibrate_pmtmr = 1; + return setup_apicmaintimer(NULL); +} +__setup("apicpmtimer", setup_apicpmtimer); + /* dummy parsing: see setup.c */ __setup("disableapic", setup_disableapic); diff --git a/arch/x86_64/kernel/pmtimer.c b/arch/x86_64/kernel/pmtimer.c index 8b2655ae4e61c..5c51d10408a67 100644 --- a/arch/x86_64/kernel/pmtimer.c +++ b/arch/x86_64/kernel/pmtimer.c @@ -80,6 +80,26 @@ int pmtimer_mark_offset(void) return lost - 1; } +static unsigned pmtimer_wait_tick(void) +{ + u32 a, b; + for (a = b = inl(pmtmr_ioport) & ACPI_PM_MASK; + a == b; + b = inl(pmtmr_ioport) & ACPI_PM_MASK) + ; + return b; +} + +/* note: wait time is rounded up to one tick */ +void pmtimer_wait(unsigned us) +{ + u32 a, b; + a = pmtimer_wait_tick(); + do { + b = inl(pmtmr_ioport); + } while (cyc2us(b - a) < us); +} + void pmtimer_resume(void) { last_pmtmr_tick = inl(pmtmr_ioport); diff --git a/include/asm-x86_64/proto.h b/include/asm-x86_64/proto.h index a6748b9568fef..c99832e7bf3f7 100644 --- a/include/asm-x86_64/proto.h +++ b/include/asm-x86_64/proto.h @@ -42,6 +42,7 @@ extern void iommu_hole_init(void); extern void time_init_gtod(void); extern int pmtimer_mark_offset(void); extern void pmtimer_resume(void); +extern void pmtimer_wait(unsigned); extern unsigned int do_gettimeoffset_pm(void); #ifdef CONFIG_X86_PM_TIMER extern u32 pmtmr_ioport; |