NetBSD/sys/arch/arm/cortex/a9tmr.c

334 lines
8.8 KiB
C

/* $NetBSD: a9tmr.c,v 1.4 2012/11/29 17:36:56 matt Exp $ */
/*-
* Copyright (c) 2012 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Matt Thomas
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: a9tmr.c,v 1.4 2012/11/29 17:36:56 matt Exp $");
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/device.h>
#include <sys/intr.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/timetc.h>
#include <prop/proplib.h>
#include <arm/cortex/a9tmr_reg.h>
#include <arm/cortex/a9tmr_var.h>
#include <arm/cortex/mpcore_var.h>
static int a9tmr_match(device_t, cfdata_t, void *);
static void a9tmr_attach(device_t, device_t, void *);
static int clockhandler(void *);
static u_int a9tmr_get_timecount(struct timecounter *);
static struct a9tmr_softc a9tmr_sc;
static struct timecounter a9tmr_timecounter = {
.tc_get_timecount = a9tmr_get_timecount,
.tc_poll_pps = 0,
.tc_counter_mask = ~0u,
.tc_frequency = 0, /* set by cpu_initclocks() */
.tc_name = NULL, /* set by attach */
.tc_quality = 500,
.tc_priv = &a9tmr_sc,
.tc_next = NULL,
};
CFATTACH_DECL_NEW(a9tmr, 0, a9tmr_match, a9tmr_attach, NULL, NULL);
static inline uint32_t
a9tmr_global_read(struct a9tmr_softc *sc, bus_size_t o)
{
return bus_space_read_4(sc->sc_memt, sc->sc_global_memh, o);
}
static inline void
a9tmr_global_write(struct a9tmr_softc *sc, bus_size_t o, uint32_t v)
{
bus_space_write_4(sc->sc_memt, sc->sc_global_memh, o, v);
}
/* ARGSUSED */
static int
a9tmr_match(device_t parent, cfdata_t cf, void *aux)
{
struct mpcore_attach_args * const mpcaa = aux;
if (a9tmr_sc.sc_dev != NULL)
return 0;
if (!CPU_ID_CORTEX_A9_P(curcpu()->ci_arm_cpuid))
return 0;
if (strcmp(mpcaa->mpcaa_name, cf->cf_name) != 0)
return 0;
/*
* This isn't present on UP A9s (since CBAR isn't present).
*/
uint32_t mpidr = armreg_mpidr_read();
if (mpidr == 0 || (mpidr & MPIDR_U))
return 0;
return 1;
}
static void
a9tmr_attach(device_t parent, device_t self, void *aux)
{
struct a9tmr_softc *sc = &a9tmr_sc;
struct mpcore_attach_args * const mpcaa = aux;
prop_dictionary_t dict = device_properties(self);
char freqbuf[sizeof("XXX SHz")];
/*
* This runs at the ARM PERIPHCLOCK which should be 1/2 of the CPU clock.
* The MD code should have setup our frequency for us.
*/
prop_number_t pn = prop_dictionary_get(dict, "frequency");
KASSERT(pn != NULL);
sc->sc_freq = prop_number_unsigned_integer_value(pn);
humanize_number(freqbuf, sizeof(freqbuf), sc->sc_freq, "Hz", 1000);
aprint_naive("\n");
aprint_normal(": A9 Global 64-bit Timer (%s)\n", freqbuf);
self->dv_private = sc;
sc->sc_dev = self;
sc->sc_memt = mpcaa->mpcaa_memt;
sc->sc_memh = mpcaa->mpcaa_memh;
evcnt_attach_dynamic(&sc->sc_ev_missing_ticks, EVCNT_TYPE_MISC, NULL,
device_xname(self), "missing interrupts");
bus_space_subregion(sc->sc_memt, sc->sc_memh,
TMR_GLOBAL_BASE, TMR_GLOBAL_BASE, &sc->sc_global_memh);
bus_space_subregion(sc->sc_memt, sc->sc_memh,
TMR_PRIVATE_BASE, TMR_PRIVATE_SIZE, &sc->sc_private_memh);
bus_space_subregion(sc->sc_memt, sc->sc_memh,
TMR_WDOG_BASE, TMR_WDOG_SIZE, &sc->sc_wdog_memh);
sc->sc_global_ih = intr_establish(IRQ_A9TMR_PPI_GTIMER, IPL_CLOCK,
IST_EDGE, clockhandler, NULL);
if (sc->sc_global_ih == NULL)
panic("%s: unable to register timer interrupt", __func__);
aprint_normal_dev(sc->sc_dev, "interrupting on irq %d\n",
IRQ_A9TMR_PPI_GTIMER);
}
static inline uint64_t
a9tmr_gettime(struct a9tmr_softc *sc)
{
uint32_t lo, hi;
do {
hi = a9tmr_global_read(sc, TMR_GBL_CTR_U);
lo = a9tmr_global_read(sc, TMR_GBL_CTR_L);
} while (hi != a9tmr_global_read(sc, TMR_GBL_CTR_U));
return ((uint64_t)hi << 32) | lo;
}
void
a9tmr_init_cpu_clock(struct cpu_info *ci)
{
struct a9tmr_softc * const sc = &a9tmr_sc;
uint64_t now = a9tmr_gettime(sc);
KASSERT(ci == curcpu());
ci->ci_lastintr = now;
a9tmr_global_write(sc, TMR_GBL_AUTOINC, sc->sc_autoinc);
/*
* To update the compare register we have to disable comparisions first.
*/
uint32_t ctl = a9tmr_global_read(sc, TMR_GBL_CTL);
if (ctl & TMR_GBL_CTL_CMP_ENABLE) {
a9tmr_global_write(sc, TMR_GBL_CTL, ctl & ~TMR_GBL_CTL_CMP_ENABLE);
}
/*
* Schedule the next interrupt.
*/
now += sc->sc_autoinc;
a9tmr_global_write(sc, TMR_GBL_CMP_L, (uint32_t) now);
a9tmr_global_write(sc, TMR_GBL_CMP_H, (uint32_t) (now >> 32));
/*
* Re-enable the comparator and now enable interrupts.
*/
a9tmr_global_write(sc, TMR_GBL_INT, 1); /* clear interrupt pending */
ctl |= TMR_GBL_CTL_CMP_ENABLE | TMR_GBL_CTL_INT_ENABLE | TMR_GBL_CTL_AUTO_INC | TMR_CTL_ENABLE;
a9tmr_global_write(sc, TMR_GBL_CTL, ctl);
#if 0
printf("%s: %s: ctl %#x autoinc %u cmp %#x%08x now %#"PRIx64"\n",
__func__, ci->ci_data.cpu_name,
a9tmr_global_read(sc, TMR_GBL_CTL),
a9tmr_global_read(sc, TMR_GBL_AUTOINC),
a9tmr_global_read(sc, TMR_GBL_CMP_H),
a9tmr_global_read(sc, TMR_GBL_CMP_L),
a9tmr_gettime(sc));
int s = splsched();
uint64_t when = now;
u_int n = 0;
while ((now = a9tmr_gettime(sc)) < when) {
/* spin */
n++;
KASSERTMSG(n <= sc->sc_autoinc,
"spun %u times but only %"PRIu64" has passed",
n, when - now);
}
printf("%s: %s: status %#x cmp %#x%08x now %#"PRIx64"\n",
__func__, ci->ci_data.cpu_name,
a9tmr_global_read(sc, TMR_GBL_INT),
a9tmr_global_read(sc, TMR_GBL_CMP_H),
a9tmr_global_read(sc, TMR_GBL_CMP_L),
a9tmr_gettime(sc));
splx(s);
#elif 0
delay(1000000 / hz + 1000);
#endif
}
void
cpu_initclocks(void)
{
struct a9tmr_softc * const sc = &a9tmr_sc;
KASSERT(sc->sc_dev != NULL);
KASSERT(sc->sc_freq != 0);
sc->sc_autoinc = sc->sc_freq / hz;
a9tmr_init_cpu_clock(curcpu());
a9tmr_timecounter.tc_name = device_xname(sc->sc_dev);
a9tmr_timecounter.tc_frequency = sc->sc_freq;
tc_init(&a9tmr_timecounter);
}
void
a9tmr_delay(unsigned int n)
{
struct a9tmr_softc * const sc = &a9tmr_sc;
KASSERT(sc != NULL);
uint32_t freq = sc->sc_freq ? sc->sc_freq : curcpu()->ci_data.cpu_cc_freq / 2;
KASSERT(freq != 0);
/*
* not quite divide by 1000000 but close enough
* (higher by 1.3% which means we wait 1.3% longer).
*/
const uint64_t incr_per_us = (freq >> 20) + (freq >> 24);
const uint64_t delta = n * incr_per_us;
const uint64_t base = a9tmr_gettime(sc);
const uint64_t finish = base + delta;
while (a9tmr_gettime(sc) < finish) {
/* spin */
}
}
/*
* clockhandler:
*
* Handle the hardclock interrupt.
*/
static int
clockhandler(void *arg)
{
struct clockframe * const cf = arg;
struct a9tmr_softc * const sc = &a9tmr_sc;
struct cpu_info * const ci = curcpu();
const uint64_t now = a9tmr_gettime(sc);
uint64_t delta = now - ci->ci_lastintr;
a9tmr_global_write(sc, TMR_GBL_INT, 1); // Ack the interrupt
#if 0
printf("%s(%p): %s: now %#"PRIx64" delta %"PRIu64"\n",
__func__, cf, ci->ci_data.cpu_name, now, delta);
#endif
KASSERTMSG(delta > sc->sc_autoinc / 100,
"%s: interrupting too quickly (delta=%"PRIu64")",
ci->ci_data.cpu_name, delta);
ci->ci_lastintr = now;
hardclock(cf);
#if 0
/*
* Try to make up up to a seconds amount of missed clock interrupts
*/
u_int ticks = hz;
for (delta -= sc->sc_autoinc;
ticks > 0 && delta >= sc->sc_autoinc;
delta -= sc->sc_autoinc, ticks--) {
hardclock(cf);
}
#else
if (delta > sc->sc_autoinc)
sc->sc_ev_missing_ticks.ev_count += delta / sc->sc_autoinc;
#endif
return 1;
}
void
setstatclockrate(int newhz)
{
}
static u_int
a9tmr_get_timecount(struct timecounter *tc)
{
struct a9tmr_softc * const sc = tc->tc_priv;
return (u_int) (a9tmr_gettime(sc));
}