> Date: Fri, 9 Dec 2022 11:28:43 -0600
> From: Scott Cheloha <scottchel...@gmail.com>
>
> sxitimer(4) is the fourth and final armv7 clock interrupt driver that
> needs to switch to clockintr.
>
> - Remove everything related to STATTIMER. We can multiplex TICKTIMER
> to handle all clock interrupt events.
> - Remove sxitimer-specific clock interrupt scheduling bits and randomized
> statclock bits.
> - Wire up sxitimer_intrclock.
>
> This is not compile-tested. When we get it to compile, it ought to
> survive a release build if that's practical for machines sporting
> sxitimer(4).
>
> What sort of machine has one of these?
I have a board with an allwinner A10 here that has it. I'll see if I
can dig it out over the weekend.
> Index: sys/arch/arm/include/cpu.h
> ===================================================================
> RCS file: /cvs/src/sys/arch/arm/include/cpu.h,v
> retrieving revision 1.61
> diff -u -p -r1.61 cpu.h
> --- sys/arch/arm/include/cpu.h 6 Jul 2021 09:34:06 -0000 1.61
> +++ sys/arch/arm/include/cpu.h 9 Dec 2022 17:27:13 -0000
> @@ -149,6 +149,7 @@ void arm32_vector_init(vaddr_t, int);
> * Per-CPU information. For now we assume one CPU.
> */
>
> +#include <sys/clockintr.h>
> #include <sys/device.h>
> #include <sys/sched.h>
> #include <sys/srp.h>
> @@ -198,7 +199,7 @@ struct cpu_info {
> #ifdef GPROF
> struct gmonparam *ci_gmon;
> #endif
> -
> + struct clockintr_queue ci_queue;
> char ci_panicbuf[512];
> };
>
> Index: sys/arch/arm/include/_types.h
> ===================================================================
> RCS file: /cvs/src/sys/arch/arm/include/_types.h,v
> retrieving revision 1.19
> diff -u -p -r1.19 _types.h
> --- sys/arch/arm/include/_types.h 5 Mar 2018 01:15:25 -0000 1.19
> +++ sys/arch/arm/include/_types.h 9 Dec 2022 17:27:13 -0000
> @@ -35,6 +35,8 @@
> #ifndef _ARM__TYPES_H_
> #define _ARM__TYPES_H_
>
> +#define __HAVE_CLOCKINTR
> +
> #if defined(_KERNEL)
> typedef struct label_t {
> long val[11];
> Index: sys/arch/armv7/sunxi/sxitimer.c
> ===================================================================
> RCS file: /cvs/src/sys/arch/armv7/sunxi/sxitimer.c,v
> retrieving revision 1.18
> diff -u -p -r1.18 sxitimer.c
> --- sys/arch/armv7/sunxi/sxitimer.c 24 Oct 2021 17:52:28 -0000 1.18
> +++ sys/arch/armv7/sunxi/sxitimer.c 9 Dec 2022 17:27:14 -0000
> @@ -20,7 +20,9 @@
> #include <sys/param.h>
> #include <sys/systm.h>
> #include <sys/kernel.h>
> +#include <sys/clockintr.h>
> #include <sys/device.h>
> +#include <sys/stdint.h>
> #include <sys/timetc.h>
>
> #include <machine/bus.h>
> @@ -94,6 +96,17 @@ static struct timecounter sxitimer_timec
> .tc_user = 0,
> };
>
> +uint64_t sxitimer_nsec_cycle_ratio;
> +uint64_t sxitimer_nsec_max;
> +
> +void sxitimer_rearm(void *, uint64_t);
> +void sxitimer_trigger(void *);
> +
> +const struct intrclock sxitimer_intrclock = {
> + .ic_rearm = sxitimer_rearm,
> + .ic_trigger = sxitimer_trigger
> +};
> +
> bus_space_tag_t sxitimer_iot;
> bus_space_handle_t sxitimer_ioh;
>
> @@ -111,11 +124,6 @@ uint32_t sxitimer_irq[] = {
> 0
> };
>
> -uint32_t sxitimer_stat_tpi, sxitimer_tick_tpi;
> -uint32_t sxitimer_statvar, sxitimer_statmin;
> -uint32_t sxitimer_tick_nextevt, sxitimer_stat_nextevt;
> -uint32_t sxitimer_ticks_err_cnt, sxitimer_ticks_err_sum;
> -
> struct sxitimer_softc {
> struct device sc_dev;
> };
> @@ -147,7 +155,6 @@ void
> sxitimer_attach(struct device *parent, struct device *self, void *aux)
> {
> struct fdt_attach_args *faa = aux;
> - uint32_t freq, ival, now;
>
> KASSERT(faa->fa_nreg > 0);
>
> @@ -163,61 +170,32 @@ sxitimer_attach(struct device *parent, s
> & CNT64_CLR_EN)
> continue;
>
> - /* timers are down-counters, from interval to 0 */
> - now = 0xffffffff; /* known big value */
> - freq = sxitimer_freq[TICKTIMER];
> -
> /* stop timer, and set clk src */
> bus_space_write_4(sxitimer_iot, sxitimer_ioh,
> TIMER_CTRL(TICKTIMER), TIMER_OSC24M);
>
> - ival = sxitimer_tick_tpi = freq / hz;
> - sxitimer_tick_nextevt = now - ival;
> -
> - sxitimer_ticks_err_cnt = freq % hz;
> - sxitimer_ticks_err_sum = 0;
> -
> - bus_space_write_4(sxitimer_iot, sxitimer_ioh,
> - TIMER_INTV(TICKTIMER), ival);
> -
> - /* timers are down-counters, from interval to 0 */
> - now = 0xffffffff; /* known big value */
> - freq = sxitimer_freq[STATTIMER];
> -
> - /* stop timer, and set clk src */
> - bus_space_write_4(sxitimer_iot, sxitimer_ioh,
> - TIMER_CTRL(STATTIMER), TIMER_OSC24M);
> + sxitimer_nsec_cycle_ratio =
> + sxitimer_freq[TICKTIMER] * (1ULL << 32) / 1000000000;
> + sxitimer_nsec_max = UINT64_MAX / sxitimer_nsec_cycle_ratio;
>
> /* 100/1000 or 128/1024 ? */
> stathz = 128;
> profhz = 1024;
> - sxitimer_setstatclockrate(stathz);
> -
> - ival = sxitimer_stat_tpi = freq / stathz;
> - sxitimer_stat_nextevt = now - ival;
> -
> - bus_space_write_4(sxitimer_iot, sxitimer_ioh,
> - TIMER_INTV(STATTIMER), ival);
> -
> - /* timers are down-counters, from interval to 0 */
> - now = 0xffffffff; /* known big value */
> - freq = sxitimer_freq[CNTRTIMER];
> + clockintr_init(CL_RNDSTAT);
>
> /* stop timer, and set clk src */
> bus_space_write_4(sxitimer_iot, sxitimer_ioh,
> TIMER_CTRL(CNTRTIMER), TIMER_OSC24M);
> + bus_space_write_4(sxitimer_iot, sxitimer_ioh,
> + TIMER_INTV(CNTRTIMER), UINT32_MAX);
>
> - ival = now;
> -
> - sxitimer_timecounter.tc_frequency = freq;
> + sxitimer_timecounter.tc_frequency = sxitimer_freq[CNTRTIMER];
> tc_init(&sxitimer_timecounter);
> +
> arm_clock_register(sxitimer_cpu_initclocks, sxitimer_delay,
> sxitimer_setstatclockrate, NULL);
>
> - printf(": %d kHz", freq / 1000);
> -
> - bus_space_write_4(sxitimer_iot, sxitimer_ioh,
> - TIMER_INTV(CNTRTIMER), ival);
> + printf(": %d kHz", sxitimer_freq[CNTRTIMER] / 1000);
>
> printf("\n");
> }
> @@ -233,20 +211,18 @@ sxitimer_cpu_initclocks(void)
> {
> uint32_t isr, ier, ctrl;
>
> - /* establish interrupts */
> + /* establish interrupt */
> arm_intr_establish(sxitimer_irq[TICKTIMER], IPL_CLOCK,
> sxitimer_tickintr, NULL, "tick");
> - arm_intr_establish(sxitimer_irq[STATTIMER], IPL_STATCLOCK,
> - sxitimer_statintr, NULL, "stattick");
>
> /* clear timer interrupt pending bits */
> isr = bus_space_read_4(sxitimer_iot, sxitimer_ioh, TIMER_ISR);
> - isr |= TIMER_IRQ(STATTIMER) | TIMER_IRQ(TICKTIMER);
> + isr |= TIMER_IRQ(TICKTIMER);
> bus_space_write_4(sxitimer_iot, sxitimer_ioh, TIMER_ISR, isr);
>
> - /* enable timer IRQs */
> + /* enable timer IRQ */
> ier = bus_space_read_4(sxitimer_iot, sxitimer_ioh, TIMER_IER);
> - ier |= TIMER_IRQ(STATTIMER) | TIMER_IRQ(TICKTIMER);
> + ier |= TIMER_IRQ(TICKTIMER);
> bus_space_write_4(sxitimer_iot, sxitimer_ioh, TIMER_IER, ier);
>
> /* enable timers */
> @@ -256,153 +232,21 @@ sxitimer_cpu_initclocks(void)
> TIMER_CTRL(CNTRTIMER),
> ctrl | TIMER_ENABLE | TIMER_RELOAD | TIMER_CONTINOUS);
>
> - ctrl = bus_space_read_4(sxitimer_iot, sxitimer_ioh,
> - TIMER_CTRL(STATTIMER));
> - bus_space_write_4(sxitimer_iot, sxitimer_ioh,
> - TIMER_CTRL(STATTIMER),
> - ctrl | TIMER_ENABLE | TIMER_RELOAD | TIMER_SINGLESHOT);
> -
> - ctrl = bus_space_read_4(sxitimer_iot, sxitimer_ioh,
> - TIMER_CTRL(TICKTIMER));
> - bus_space_write_4(sxitimer_iot, sxitimer_ioh,
> - TIMER_CTRL(TICKTIMER),
> - ctrl | TIMER_ENABLE | TIMER_RELOAD | TIMER_SINGLESHOT);
> + /* start clock interrupt cycle */
> + clockintr_cpu_init(&sxitimer_intrclock);
> + clockintr_trigger();
> }
>
> -/*
> - * 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.
> - *
> - * To work around this two timers are used, one is used as a reference
> - * clock without reload, however we just disable the interrupt it
> - * could 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.
> - */
> -/* XXX update above comment */
> int
> sxitimer_tickintr(void *frame)
> {
> - uint32_t now, nextevent;
> - uint32_t val;
> - int rc = 0;
> -
> splassert(IPL_CLOCK);
>
> /* clear timer pending interrupt bit */
> bus_space_write_4(sxitimer_iot, sxitimer_ioh,
> TIMER_ISR, TIMER_IRQ(TICKTIMER));
>
> - now = sxitimer_readcnt32();
> -
> - while ((int32_t)(now - sxitimer_tick_nextevt) < 0) {
> - sxitimer_tick_nextevt -= sxitimer_tick_tpi;
> - sxitimer_ticks_err_sum += sxitimer_ticks_err_cnt;
> -
> - while (sxitimer_ticks_err_sum > hz) {
> - sxitimer_tick_nextevt += 1;
> - sxitimer_ticks_err_sum -= hz;
> - }
> -
> - rc = 1;
> - hardclock(frame);
> - }
> - nextevent = now - sxitimer_tick_nextevt;
> - if (nextevent < 10 /* XXX */)
> - nextevent = 10;
> -
> - if (nextevent > sxitimer_tick_tpi) {
> - /*
> - * 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.
> - */
> - nextevent = sxitimer_tick_tpi;
> - sxitimer_tick_nextevt = now;
> - }
> -
> - val = bus_space_read_4(sxitimer_iot, sxitimer_ioh,
> - TIMER_CTRL(TICKTIMER));
> - bus_space_write_4(sxitimer_iot, sxitimer_ioh,
> - TIMER_CTRL(TICKTIMER), val & ~TIMER_ENABLE);
> -
> - sxitimer_sync();
> -
> - bus_space_write_4(sxitimer_iot, sxitimer_ioh,
> - TIMER_INTV(TICKTIMER), nextevent);
> -
> - val = bus_space_read_4(sxitimer_iot, sxitimer_ioh,
> - TIMER_CTRL(TICKTIMER));
> - bus_space_write_4(sxitimer_iot, sxitimer_ioh,
> - TIMER_CTRL(TICKTIMER),
> - val | TIMER_ENABLE | TIMER_RELOAD | TIMER_SINGLESHOT);
> -
> - return rc;
> -}
> -
> -int
> -sxitimer_statintr(void *frame)
> -{
> - uint32_t now, nextevent, r;
> - uint32_t val;
> - int rc = 0;
> -
> - splassert(IPL_STATCLOCK);
> -
> - /* clear timer pending interrupt bit */
> - bus_space_write_4(sxitimer_iot, sxitimer_ioh,
> - TIMER_ISR, TIMER_IRQ(STATTIMER));
> -
> - now = sxitimer_readcnt32();
> - while ((int32_t)(now - sxitimer_stat_nextevt) < 0) {
> - do {
> - r = random() & (sxitimer_statvar -1);
> - } while (r == 0); /* random == 0 not allowed */
> - sxitimer_stat_nextevt -= sxitimer_statmin + r;
> - rc = 1;
> - statclock(frame);
> - }
> -
> - nextevent = now - sxitimer_stat_nextevt;
> -
> - if (nextevent < 10 /* XXX */)
> - nextevent = 10;
> -
> - if (nextevent > sxitimer_stat_tpi) {
> - /*
> - * 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.
> - */
> - nextevent = sxitimer_stat_tpi;
> - sxitimer_stat_nextevt = now;
> - }
> -
> - val = bus_space_read_4(sxitimer_iot, sxitimer_ioh,
> - TIMER_CTRL(STATTIMER));
> - bus_space_write_4(sxitimer_iot, sxitimer_ioh,
> - TIMER_CTRL(STATTIMER), val & ~TIMER_ENABLE);
> -
> - sxitimer_sync();
> -
> - bus_space_write_4(sxitimer_iot, sxitimer_ioh,
> - TIMER_INTV(STATTIMER), nextevent);
> -
> - val = bus_space_read_4(sxitimer_iot, sxitimer_ioh,
> - TIMER_CTRL(STATTIMER));
> - bus_space_write_4(sxitimer_iot, sxitimer_ioh,
> - TIMER_CTRL(STATTIMER),
> - val | TIMER_ENABLE | TIMER_RELOAD | TIMER_SINGLESHOT);
> -
> - return rc;
> + return clockintr_dispatch(frame);
> }
>
> uint64_t
> @@ -457,29 +301,62 @@ sxitimer_delay(u_int usecs)
> void
> sxitimer_setstatclockrate(int newhz)
> {
> - int minint, statint, s;
> -
> - s = splstatclock();
> -
> - statint = sxitimer_freq[STATTIMER] / newhz;
> - /* calculate largest 2^n which is smaller than just over half statint */
> - sxitimer_statvar = 0x40000000; /* really big power of two */
> - minint = statint / 2 + 100;
> - while (sxitimer_statvar > minint)
> - sxitimer_statvar >>= 1;
> -
> - sxitimer_statmin = statint - (sxitimer_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);
> }
>
> u_int
> sxitimer_get_timecount(struct timecounter *tc)
> {
> return (u_int)UINT_MAX - sxitimer_readcnt32();
> +}
> +
> +void
> +sxitimer_rearm(void *unused, uint64_t nsecs)
> +{
> + uint32_t ctrl, cycles;
> +
> + if (nsecs > sxitimer_nsec_max)
> + nsecs = sxitimer_nsec_max;
> + cycles = (nsecs * sxitimer_nsec_cycle_ratio) >> 32;
> + if (cycles < 10)
> + cycles = 10; /* XXX Why do we need to round up to 10? */
> +
> + ctrl = bus_space_read_4(sxitimer_iot, sxitimer_ioh,
> + TIMER_CTRL(TICKTIMER));
> + bus_space_write_4(sxitimer_iot, sxitimer_ioh,
> + TIMER_CTRL(TICKTIMER), ctrl & ~TIMER_ENABLE);
> +
> + sxitimer_sync();
> +
> + bus_space_write_4(sxitimer_iot, sxitimer_ioh,
> + TIMER_INTV(TICKTIMER), cycles);
> +
> + ctrl = bus_space_read_4(sxitimer_iot, sxitimer_ioh,
> + TIMER_CTRL(TICKTIMER));
> + bus_space_write_4(sxitimer_iot, sxitimer_ioh,
> + TIMER_CTRL(TICKTIMER),
> + ctrl | TIMER_ENABLE | TIMER_RELOAD | TIMER_SINGLESHOT);
> +}
> +
> +void
> +sxitimer_trigger(void *unused)
> +{
> + uint32_t ctrl;
> +
> + ctrl = bus_space_read_4(sxitimer_iot, sxitimer_ioh,
> + TIMER_CTRL(TICKTIMER));
> + bus_space_write_4(sxitimer_iot, sxitimer_ioh,
> + TIMER_CTRL(TICKTIMER), ctrl & ~TIMER_ENABLE);
> +
> + sxitimer_sync();
> +
> + /* XXX Why do we need to round up to 10? */
> + bus_space_write_4(sxitimer_iot, sxitimer_ioh,
> + TIMER_INTV(TICKTIMER), 10);
> +
> + ctrl = bus_space_read_4(sxitimer_iot, sxitimer_ioh,
> + TIMER_CTRL(TICKTIMER));
> + bus_space_write_4(sxitimer_iot, sxitimer_ioh,
> + TIMER_CTRL(TICKTIMER),
> + ctrl | TIMER_ENABLE | TIMER_RELOAD | TIMER_SINGLESHOT);
> }
>
>
