Implement new event timers infrastructure. It provides unified APIs for

writing event timer drivers, for choosing best possible drivers by machine
independent code and for operating them to supply kernel with hardclock(),
statclock() and profclock() events in unified fashion on various hardware.

Infrastructure provides support for both per-CPU (independent for every CPU
core) and global timers in periodic and one-shot modes. MI management code
at this moment uses only periodic mode, but one-shot mode use planned for
later, as part of tickless kernel project.

For this moment infrastructure used on i386 and amd64 architectures. Other
archs are welcome to follow, while their current operation should not be
affected.

This patch updates existing drivers (i8254, RTC and LAPIC) for the new
order, and adds event timers support into the HPET driver. These drivers
have different capabilities:
 LAPIC - per-CPU timer, supports periodic and one-shot operation, may
freeze in C3 state, calibrated on first use, so may be not exactly precise.
 HPET - depending on hardware can work as per-CPU or global, supports
periodic and one-shot operation, usually provides several event timers.
 i8254 - global, limited to periodic mode, because same hardware used also
as time counter.
 RTC - global, supports only periodic mode, set of frequencies in Hz
limited by powers of 2.

Depending on hardware capabilities, drivers preferred in following orders,
either LAPIC, HPETs, i8254, RTC or HPETs, LAPIC, i8254, RTC.
User may explicitly specify wanted timers via loader tunables or sysctls:
kern.eventtimer.timer1 and kern.eventtimer.timer2.
If requested driver is unavailable or unoperational, system will try to
replace it. If no more timers available or "NONE" specified for second,
system will operate using only one timer, multiplying it's frequency by few
times and uing respective dividers to honor hz, stathz and profhz values,
set during initial setup.

1 files changed, 22 insertions, 39 deletions

diff --git a/sys/pc98/cbus/clock.c b/sys/pc98/cbus/clock.c
index 2f2c08c..2596571 100644
--- a/sys/pc98/cbus/clock.c
+++ b/sys/pc98/cbus/clock.c
@@ -93,16 +93,12 @@ TUNABLE_INT("hw.i8254.freq", &i8254_freq);
 int	i8254_max_count;
 static int i8254_real_max_count;
 
-static int lapic_allclocks = 1;
-TUNABLE_INT("machdep.lapic_allclocks", &lapic_allclocks);
-
 static	struct mtx clock_lock;
 static	struct intsrc *i8254_intsrc;
 static	u_int32_t i8254_lastcount;
 static	u_int32_t i8254_offset;
 static	int	(*i8254_pending)(struct intsrc *);
 static	int	i8254_ticked;
-static	enum lapic_clock using_lapic_timer = LAPIC_CLOCK_NONE;
 
 /* Values for timerX_state: */
 #define	RELEASED	0
@@ -113,7 +109,9 @@ static	enum lapic_clock using_lapic_timer = LAPIC_CLOCK_NONE;
 static	u_char	timer1_state;
 
 static	unsigned i8254_get_timecount(struct timecounter *tc);
+#if 0
 static	unsigned i8254_simple_get_timecount(struct timecounter *tc);
+#endif
 static	void	set_i8254_freq(u_int freq, int intr_freq);
 
 static struct timecounter i8254_timecounter = {
@@ -155,8 +153,6 @@ clkintr(struct trapframe *frame)
 		clkintr_pending = 0;
 		mtx_unlock_spin(&clock_lock);
 	}
-	KASSERT(using_lapic_timer == LAPIC_CLOCK_NONE,
-	    ("clk interrupt enabled with lapic timer"));
 
 #ifdef KDTRACE_HOOKS
 	/*
@@ -352,7 +348,7 @@ set_i8254_freq(u_int freq, int intr_freq)
 	i8254_timecounter.tc_frequency = freq;
 	mtx_lock_spin(&clock_lock);
 	i8254_freq = freq;
-	if (using_lapic_timer != LAPIC_CLOCK_NONE)
+	if (intr_freq == 0)
 		new_i8254_real_max_count = 0x10000;
 	else
 		new_i8254_real_max_count = TIMER_DIV(intr_freq);
@@ -425,45 +421,30 @@ startrtclock()
 void
 cpu_initclocks()
 {
-#if defined(DEV_APIC)
-	enum lapic_clock tlsca;
 
-	tlsca = lapic_allclocks == 0 ? LAPIC_CLOCK_HARDCLOCK : LAPIC_CLOCK_ALL;
-	using_lapic_timer = lapic_setup_clock(tlsca);
-#endif
-	/*
-	 * If we aren't using the local APIC timer to drive the kernel
-	 * clocks, setup the interrupt handler for the 8254 timer 0 so
-	 * that it can drive hardclock().  Otherwise, change the 8254
-	 * timecounter to user a simpler algorithm.
-	 */
-	if (using_lapic_timer == LAPIC_CLOCK_NONE) {
-		timer1hz = hz;
-		intr_add_handler("clk", 0, (driver_filter_t *)clkintr, NULL,
-		    NULL, INTR_TYPE_CLK, NULL);
-		i8254_intsrc = intr_lookup_source(0);
-		if (i8254_intsrc != NULL)
-			i8254_pending =
-			    i8254_intsrc->is_pic->pic_source_pending;
-	} else {
-		i8254_timecounter.tc_get_timecount =
-		    i8254_simple_get_timecount;
-		i8254_timecounter.tc_counter_mask = 0xffff;
-		set_i8254_freq(i8254_freq, hz);
-	}
-	if (using_lapic_timer != LAPIC_CLOCK_ALL) {
-		profhz = hz;
-		if (hz < 128)
-			stathz = hz;
-		else
-			stathz = hz / (hz / 128);
-	}
+	timer1hz = hz;
+	intr_add_handler("clk", 0, (driver_filter_t *)clkintr, NULL,
+	    NULL, INTR_TYPE_CLK, NULL);
+	i8254_intsrc = intr_lookup_source(0);
+	if (i8254_intsrc != NULL)
+		i8254_pending =
+		    i8254_intsrc->is_pic->pic_source_pending;
+	profhz = hz;
+	if (hz < 128)
+		stathz = hz;
+	else
+		stathz = hz / (hz / 128);
 	timer2hz = 0;
 
 	init_TSC_tc();
 }
 
 void
+cpu_initclocks_ap(void)
+{
+}
+
+void
 cpu_startprofclock(void)
 {
 }
@@ -493,12 +474,14 @@ sysctl_machdep_i8254_freq(SYSCTL_HANDLER_ARGS)
 SYSCTL_PROC(_machdep, OID_AUTO, i8254_freq, CTLTYPE_INT | CTLFLAG_RW,
     0, sizeof(u_int), sysctl_machdep_i8254_freq, "IU", "");
 
+#if 0
 static unsigned
 i8254_simple_get_timecount(struct timecounter *tc)
 {
 
 	return (i8254_max_count - getit());
 }
+#endif
 
 static unsigned
 i8254_get_timecount(struct timecounter *tc)