diff options
Diffstat (limited to 'arch/x86/kernel/hpet.c')
| -rw-r--r-- | arch/x86/kernel/hpet.c | 41 |
1 files changed, 31 insertions, 10 deletions
diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c index ad80a1c718c6..7494999141b3 100644 --- a/arch/x86/kernel/hpet.c +++ b/arch/x86/kernel/hpet.c @@ -4,6 +4,7 @@ #include <linux/sysdev.h> #include <linux/delay.h> #include <linux/errno.h> +#include <linux/slab.h> #include <linux/hpet.h> #include <linux/init.h> #include <linux/cpu.h> @@ -15,7 +16,6 @@ #include <asm/hpet.h> #define HPET_MASK CLOCKSOURCE_MASK(32) -#define HPET_SHIFT 22 /* FSEC = 10^-15 NSEC = 10^-9 */ @@ -266,7 +266,7 @@ static void hpet_resume_device(void) force_hpet_resume(); } -static void hpet_resume_counter(void) +static void hpet_resume_counter(struct clocksource *cs) { hpet_resume_device(); hpet_restart_counter(); @@ -399,9 +399,23 @@ static int hpet_next_event(unsigned long delta, * then we might have a real hardware problem. We can not do * much about it here, but at least alert the user/admin with * a prominent warning. + * + * An erratum on some chipsets (ICH9,..), results in + * comparator read immediately following a write returning old + * value. Workaround for this is to read this value second + * time, when first read returns old value. + * + * In fact the write to the comparator register is delayed up + * to two HPET cycles so the workaround we tried to restrict + * the readback to those known to be borked ATI chipsets + * failed miserably. So we give up on optimizations forever + * and penalize all HPET incarnations unconditionally. */ - WARN_ONCE(hpet_readl(HPET_Tn_CMP(timer)) != cnt, - KERN_WARNING "hpet: compare register read back failed.\n"); + if (unlikely((u32)hpet_readl(HPET_Tn_CMP(timer)) != cnt)) { + if (hpet_readl(HPET_Tn_CMP(timer)) != cnt) + printk_once(KERN_WARNING + "hpet: compare register read back failed.\n"); + } return (s32)(hpet_readl(HPET_COUNTER) - cnt) >= 0 ? -ETIME : 0; } @@ -492,7 +506,7 @@ static int hpet_assign_irq(struct hpet_dev *dev) { unsigned int irq; - irq = create_irq(); + irq = create_irq_nr(0, -1); if (!irq) return -EINVAL; @@ -571,7 +585,7 @@ static void init_one_hpet_msi_clockevent(struct hpet_dev *hdev, int cpu) * scaled math multiplication factor for nanosecond to hpet tick * conversion. */ - hpet_freq = 1000000000000000ULL; + hpet_freq = FSEC_PER_SEC; do_div(hpet_freq, hpet_period); evt->mult = div_sc((unsigned long) hpet_freq, NSEC_PER_SEC, evt->shift); @@ -775,7 +789,6 @@ static struct clocksource clocksource_hpet = { .rating = 250, .read = read_hpet, .mask = HPET_MASK, - .shift = HPET_SHIFT, .flags = CLOCK_SOURCE_IS_CONTINUOUS, .resume = hpet_resume_counter, #ifdef CONFIG_X86_64 @@ -786,6 +799,7 @@ static struct clocksource clocksource_hpet = { static int hpet_clocksource_register(void) { u64 start, now; + u64 hpet_freq; cycle_t t1; /* Start the counter */ @@ -820,9 +834,15 @@ static int hpet_clocksource_register(void) * mult = (hpet_period * 2^shift)/10^6 * mult = (hpet_period << shift)/FSEC_PER_NSEC */ - clocksource_hpet.mult = div_sc(hpet_period, FSEC_PER_NSEC, HPET_SHIFT); - clocksource_register(&clocksource_hpet); + /* Need to convert hpet_period (fsec/cyc) to cyc/sec: + * + * cyc/sec = FSEC_PER_SEC/hpet_period(fsec/cyc) + * cyc/sec = (FSEC_PER_NSEC * NSEC_PER_SEC)/hpet_period + */ + hpet_freq = FSEC_PER_SEC; + do_div(hpet_freq, hpet_period); + clocksource_register_hz(&clocksource_hpet, (u32)hpet_freq); return 0; } @@ -952,7 +972,7 @@ fs_initcall(hpet_late_init); void hpet_disable(void) { - if (is_hpet_capable()) { + if (is_hpet_capable() && hpet_virt_address) { unsigned int cfg = hpet_readl(HPET_CFG); if (hpet_legacy_int_enabled) { @@ -1143,6 +1163,7 @@ int hpet_set_periodic_freq(unsigned long freq) do_div(clc, freq); clc >>= hpet_clockevent.shift; hpet_pie_delta = clc; + hpet_pie_limit = 0; } return 1; } |