diff options
Diffstat (limited to 'arch/x86/kernel/hpet.c')
| -rw-r--r-- | arch/x86/kernel/hpet.c | 82 |
1 files changed, 39 insertions, 43 deletions
diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c index 33dbcc4..4ff5968 100644 --- a/arch/x86/kernel/hpet.c +++ b/arch/x86/kernel/hpet.c @@ -27,6 +27,9 @@ #define HPET_DEV_FSB_CAP 0x1000 #define HPET_DEV_PERI_CAP 0x2000 +#define HPET_MIN_CYCLES 128 +#define HPET_MIN_PROG_DELTA (HPET_MIN_CYCLES + (HPET_MIN_CYCLES >> 1)) + #define EVT_TO_HPET_DEV(evt) container_of(evt, struct hpet_dev, evt) /* @@ -35,7 +38,6 @@ unsigned long hpet_address; u8 hpet_blockid; /* OS timer block num */ u8 hpet_msi_disable; -u8 hpet_readback_cmp; #ifdef CONFIG_PCI_MSI static unsigned long hpet_num_timers; @@ -300,8 +302,9 @@ static void hpet_legacy_clockevent_register(void) /* Calculate the min / max delta */ hpet_clockevent.max_delta_ns = clockevent_delta2ns(0x7FFFFFFF, &hpet_clockevent); - /* 5 usec minimum reprogramming delta. */ - hpet_clockevent.min_delta_ns = 5000; + /* Setup minimum reprogramming delta. */ + hpet_clockevent.min_delta_ns = clockevent_delta2ns(HPET_MIN_PROG_DELTA, + &hpet_clockevent); /* * Start hpet with the boot cpu mask and make it @@ -381,40 +384,37 @@ static int hpet_next_event(unsigned long delta, struct clock_event_device *evt, int timer) { u32 cnt; + s32 res; cnt = hpet_readl(HPET_COUNTER); cnt += (u32) delta; hpet_writel(cnt, HPET_Tn_CMP(timer)); /* - * We need to read back the CMP register on certain HPET - * implementations (ATI chipsets) which seem to delay the - * transfer of the compare register into the internal compare - * logic. With small deltas this might actually be too late as - * the counter could already be higher than the compare value - * at that point and we would wait for the next hpet interrupt - * forever. We found out that reading the CMP register back - * forces the transfer so we can rely on the comparison with - * the counter register below. - * - * That works fine on those ATI chipsets, but on newer Intel - * chipsets (ICH9...) this triggers due to an erratum: Reading - * the comparator immediately following a write is returning - * the old value. - * - * We restrict the read back to the affected ATI chipsets (set - * by quirks) and also run it with hpet=verbose for debugging - * purposes. + * HPETs are a complete disaster. The compare register is + * based on a equal comparison and neither provides a less + * than or equal functionality (which would require to take + * the wraparound into account) nor a simple count down event + * mode. Further the write to the comparator register is + * delayed internally up to two HPET clock cycles in certain + * chipsets (ATI, ICH9,10). Some newer AMD chipsets have even + * longer delays. We worked around that by reading back the + * compare register, but that required another workaround for + * ICH9,10 chips where the first readout after write can + * return the old stale value. We already had a minimum + * programming delta of 5us enforced, but a NMI or SMI hitting + * between the counter readout and the comparator write can + * move us behind that point easily. Now instead of reading + * the compare register back several times, we make the ETIME + * decision based on the following: Return ETIME if the + * counter value after the write is less than HPET_MIN_CYCLES + * away from the event or if the counter is already ahead of + * the event. The minimum programming delta for the generic + * clockevents code is set to 1.5 * HPET_MIN_CYCLES. */ - if (hpet_readback_cmp || hpet_verbose) { - u32 cmp = hpet_readl(HPET_Tn_CMP(timer)); + res = (s32)(cnt - hpet_readl(HPET_COUNTER)); - if (cmp != cnt) - printk_once(KERN_WARNING - "hpet: compare register read back failed.\n"); - } - - return (s32)(hpet_readl(HPET_COUNTER) - cnt) >= 0 ? -ETIME : 0; + return res < HPET_MIN_CYCLES ? -ETIME : 0; } static void hpet_legacy_set_mode(enum clock_event_mode mode, @@ -437,9 +437,9 @@ static int hpet_legacy_next_event(unsigned long delta, static DEFINE_PER_CPU(struct hpet_dev *, cpu_hpet_dev); static struct hpet_dev *hpet_devs; -void hpet_msi_unmask(unsigned int irq) +void hpet_msi_unmask(struct irq_data *data) { - struct hpet_dev *hdev = get_irq_data(irq); + struct hpet_dev *hdev = data->handler_data; unsigned int cfg; /* unmask it */ @@ -448,10 +448,10 @@ void hpet_msi_unmask(unsigned int irq) hpet_writel(cfg, HPET_Tn_CFG(hdev->num)); } -void hpet_msi_mask(unsigned int irq) +void hpet_msi_mask(struct irq_data *data) { + struct hpet_dev *hdev = data->handler_data; unsigned int cfg; - struct hpet_dev *hdev = get_irq_data(irq); /* mask it */ cfg = hpet_readl(HPET_Tn_CFG(hdev->num)); @@ -459,18 +459,14 @@ void hpet_msi_mask(unsigned int irq) hpet_writel(cfg, HPET_Tn_CFG(hdev->num)); } -void hpet_msi_write(unsigned int irq, struct msi_msg *msg) +void hpet_msi_write(struct hpet_dev *hdev, struct msi_msg *msg) { - struct hpet_dev *hdev = get_irq_data(irq); - hpet_writel(msg->data, HPET_Tn_ROUTE(hdev->num)); hpet_writel(msg->address_lo, HPET_Tn_ROUTE(hdev->num) + 4); } -void hpet_msi_read(unsigned int irq, struct msi_msg *msg) +void hpet_msi_read(struct hpet_dev *hdev, struct msi_msg *msg) { - struct hpet_dev *hdev = get_irq_data(irq); - msg->data = hpet_readl(HPET_Tn_ROUTE(hdev->num)); msg->address_lo = hpet_readl(HPET_Tn_ROUTE(hdev->num) + 4); msg->address_hi = 0; @@ -503,7 +499,7 @@ 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; @@ -582,7 +578,7 @@ 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); @@ -723,7 +719,7 @@ static int hpet_cpuhp_notify(struct notifier_block *n, switch (action & 0xf) { case CPU_ONLINE: - INIT_DELAYED_WORK_ON_STACK(&work.work, hpet_work); + INIT_DELAYED_WORK_ONSTACK(&work.work, hpet_work); init_completion(&work.complete); /* FIXME: add schedule_work_on() */ schedule_delayed_work_on(cpu, &work.work, 0); @@ -837,7 +833,7 @@ static int hpet_clocksource_register(void) * cyc/sec = FSEC_PER_SEC/hpet_period(fsec/cyc) * cyc/sec = (FSEC_PER_NSEC * NSEC_PER_SEC)/hpet_period */ - hpet_freq = FSEC_PER_NSEC * NSEC_PER_SEC; + hpet_freq = FSEC_PER_SEC; do_div(hpet_freq, hpet_period); clocksource_register_hz(&clocksource_hpet, (u32)hpet_freq); |
