-/* $OpenBSD: gptimer.c,v 1.17 2023/01/22 18:36:38 cheloha Exp $ */
+/* $OpenBSD: gptimer.c,v 1.18 2023/01/25 14:14:39 cheloha Exp $ */
/*
* Copyright (c) 2007,2009 Dale Rahn <drahn@openbsd.org>
*
#include <sys/param.h>
#include <sys/systm.h>
+#include <sys/clockintr.h>
#include <sys/kernel.h>
#include <sys/evcount.h>
#include <sys/device.h>
+#include <sys/stdint.h>
#include <sys/timetc.h>
#include <machine/bus.h>
#include <armv7/armv7/armv7var.h>
#define TIMER_FREQUENCY 32768 /* 32kHz is used, selectable */
-static struct evcount clk_count;
-static struct evcount stat_count;
-
void gptimer_attach(struct device *parent, struct device *self, void *args);
int gptimer_intr(void *frame);
void gptimer_wait(int reg);
void gptimer_cpu_initclocks(void);
void gptimer_delay(u_int);
+void gptimer_reset_tisr(void);
void gptimer_setstatclockrate(int newhz);
bus_space_tag_t gptimer_iot;
.tc_user = 0,
};
-volatile u_int32_t nexttickevent;
-volatile u_int32_t nextstatevent;
-u_int32_t ticks_per_second;
-u_int32_t ticks_per_intr;
-u_int32_t ticks_err_cnt;
-u_int32_t ticks_err_sum;
-u_int32_t statvar, statmin;
+uint64_t gptimer_nsec_cycle_ratio;
+uint64_t gptimer_nsec_max;
+
+void gptimer_rearm(void *, uint64_t);
+void gptimer_trigger(void *);
+
+const struct intrclock gptimer_intrclock = {
+ .ic_rearm = gptimer_rearm,
+ .ic_trigger = gptimer_trigger
+};
const struct cfattach gptimer_ca = {
sizeof (struct device), NULL, gptimer_attach
gptimer_setstatclockrate, NULL);
}
-/*
- * See comment in arm/xscale/i80321_clock.c
- *
- * counter is count up, but with autoreload timers it is not possible
- * to detect how many interrupts passed while interrupts were blocked.
- * also it is not possible to atomically add to the register
- * get get it to precisely fire at a non-fixed interval.
- *
- * To work around this two timers are used, GPT1 is used as a reference
- * clock without reload , however we just ignore the interrupt it
- * would (may?) generate.
- *
- * Internally this keeps track of when the next timer should fire
- * and based on that time and the current value of the reference
- * clock a number is written into the timer count register to schedule
- * the next event.
- */
-
int
gptimer_intr(void *frame)
{
- u_int32_t now, r;
- u_int32_t nextevent, duration;
-
- /* clear interrupt */
- now = bus_space_read_4(gptimer_iot, gptimer_ioh1, GP_TCRR);
-
- while ((int32_t) (nexttickevent - now) < 0) {
- nexttickevent += ticks_per_intr;
- ticks_err_sum += ticks_err_cnt;
-#if 0
- if (ticks_err_sum > hz) {
- u_int32_t match_error;
- match_error = ticks_err_sum / hz
- ticks_err_sum -= (match_error * hz);
- }
-#else
- /* looping a few times is faster than divide */
- while (ticks_err_sum > hz) {
- nexttickevent += 1;
- ticks_err_sum -= hz;
- }
-#endif
- clk_count.ec_count++;
- hardclock(frame);
- }
- while ((int32_t) (nextstatevent - now) < 0) {
- do {
- r = random() & (statvar -1);
- } while (r == 0); /* random == 0 not allowed */
- nextstatevent += statmin + r;
- /* XXX - correct nextstatevent? */
- stat_count.ec_count++;
- statclock(frame);
- }
- if ((nexttickevent - now) < (nextstatevent - now))
- nextevent = nexttickevent;
- else
- nextevent = nextstatevent;
-
-/* XXX */
- duration = nextevent -
- bus_space_read_4(gptimer_iot, gptimer_ioh1, GP_TCRR);
-#if 0
- printf("duration 0x%x %x %x\n", nextevent -
- bus_space_read_4(gptimer_iot, gptimer_ioh1, GP_TCRR),
- bus_space_read_4(gptimer_iot, gptimer_ioh0, GP_TCRR),
- bus_space_read_4(gptimer_iot, gptimer_ioh1, GP_TCRR));
-#endif
-
-
- if (duration <= 0)
- duration = 1; /* trigger immediately. */
-
- if (duration > ticks_per_intr) {
- /*
- * If interrupts are blocked too long, like during
- * the root prompt or ddb, the timer can roll over,
- * this will allow the system to continue to run
- * even if time is lost.
- */
- duration = ticks_per_intr;
- nexttickevent = now;
- nextstatevent = now;
- }
-
- gptimer_wait(GP_TWPS_ALL);
- bus_space_write_4(gptimer_iot, gptimer_ioh0, GP_TISR,
- bus_space_read_4(gptimer_iot, gptimer_ioh0, GP_TISR));
- gptimer_wait(GP_TWPS_ALL);
- bus_space_write_4(gptimer_iot, gptimer_ioh0, GP_TCRR, -duration);
-
+ clockintr_dispatch(frame);
return 1;
}
void
gptimer_cpu_initclocks(void)
{
- stathz = 128;
- profhz = 1024;
-
- ticks_per_second = TIMER_FREQUENCY;
+ stathz = hz;
+ profhz = stathz * 10;
+ clockintr_init(CL_RNDSTAT);
- setstatclockrate(stathz);
-
- ticks_per_intr = ticks_per_second / hz;
- ticks_err_cnt = ticks_per_second % hz;
- ticks_err_sum = 0;
+ gptimer_nsec_cycle_ratio = TIMER_FREQUENCY * (1ULL << 32) / 1000000000;
+ gptimer_nsec_max = UINT64_MAX / gptimer_nsec_cycle_ratio;
prcm_setclock(1, PRCM_CLK_SPEED_32);
prcm_setclock(2, PRCM_CLK_SPEED_32);
+
/* establish interrupts */
arm_intr_establish(gptimer_irq, IPL_CLOCK, gptimer_intr,
NULL, "tick");
/* setup timer 0 (hardware timer 2) */
/* reset? - XXX */
-
- bus_space_write_4(gptimer_iot, gptimer_ioh0, GP_TLDR, 0);
-
- nexttickevent = nextstatevent = bus_space_read_4(gptimer_iot,
- gptimer_ioh1, GP_TCRR) + ticks_per_intr;
-
gptimer_wait(GP_TWPS_ALL);
bus_space_write_4(gptimer_iot, gptimer_ioh0, GP_TIER, GP_TIER_OVF_EN);
gptimer_wait(GP_TWPS_ALL);
bus_space_write_4(gptimer_iot, gptimer_ioh0, GP_TWER, GP_TWER_OVF_EN);
gptimer_wait(GP_TWPS_ALL);
- bus_space_write_4(gptimer_iot, gptimer_ioh0, GP_TCLR,
- GP_TCLR_AR | GP_TCLR_ST);
- gptimer_wait(GP_TWPS_ALL);
- bus_space_write_4(gptimer_iot, gptimer_ioh0, GP_TISR,
- bus_space_read_4(gptimer_iot, gptimer_ioh0, GP_TISR));
- gptimer_wait(GP_TWPS_ALL);
- bus_space_write_4(gptimer_iot, gptimer_ioh0, GP_TCRR, -ticks_per_intr);
- gptimer_wait(GP_TWPS_ALL);
+
+ /* start the clock interrupt cycle */
+ clockintr_cpu_init(&gptimer_intrclock);
+ clockintr_trigger();
}
void
;
}
+/*
+ * Clear all interrupt status bits.
+ */
+void
+gptimer_reset_tisr(void)
+{
+ u_int32_t tisr;
+
+ tisr = bus_space_read_4(gptimer_iot, gptimer_ioh0, GP_TISR);
+ bus_space_write_4(gptimer_iot, gptimer_ioh0, GP_TISR, tisr);
+}
+
+void
+gptimer_rearm(void *unused, uint64_t nsecs)
+{
+ uint32_t cycles;
+ u_long s;
+
+ if (nsecs > gptimer_nsec_max)
+ nsecs = gptimer_nsec_max;
+ cycles = (nsecs * gptimer_nsec_cycle_ratio) >> 32;
+
+ s = intr_disable();
+ gptimer_reset_tisr();
+ bus_space_write_4(gptimer_iot, gptimer_ioh0, GP_TCRR,
+ UINT32_MAX - cycles);
+ bus_space_write_4(gptimer_iot, gptimer_ioh0, GP_TCLR, GP_TCLR_ST);
+ gptimer_wait(GP_TWPS_ALL);
+ intr_restore(s);
+}
+
+void
+gptimer_trigger(void *unused)
+{
+ u_long s;
+
+ s = intr_disable();
+
+ /* stop timer. */
+ bus_space_write_4(gptimer_iot, gptimer_ioh0, GP_TCLR, 0);
+ gptimer_wait(GP_TWPS_ALL);
+
+ /* clear interrupt status bits. */
+ gptimer_reset_tisr();
+
+ /* set shortest possible timeout. */
+ bus_space_write_4(gptimer_iot, gptimer_ioh0, GP_TCRR, UINT32_MAX);
+
+ /* start timer, wait for writes to post. */
+ bus_space_write_4(gptimer_iot, gptimer_ioh0, GP_TCLR, GP_TCLR_ST);
+ gptimer_wait(GP_TWPS_ALL);
+
+ intr_restore(s);
+}
+
void
gptimer_delay(u_int usecs)
{
void
gptimer_setstatclockrate(int newhz)
{
- int minint, statint;
- int s;
-
- s = splclock();
-
- statint = ticks_per_second / newhz;
- /* calculate largest 2^n which is smaller that just over half statint */
- statvar = 0x40000000; /* really big power of two */
- minint = statint / 2 + 100;
- while (statvar > minint)
- statvar >>= 1;
-
- statmin = statint - (statvar >> 1);
-
- splx(s);
-
- /*
- * XXX this allows the next stat timer to occur then it switches
- * to the new frequency. Rather than switching instantly.
- */
+ clockintr_setstatclockrate(newhz);
}
projects / openbsd / commitdiff