#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)
/*
/* 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
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. If the read back from the
- * compare register does not match the value we programmed
- * 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.
+ * 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 (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");
- }
+ res = (s32)(cnt - hpet_readl(HPET_COUNTER));
- 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,
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 */
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));
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;
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);
projects / mv-sheeva.git / blobdiff