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

268 lines
6.8 KiB
C

/* $NetBSD: gtmr.c,v 1.2 2013/06/20 05:30:21 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: gtmr.c,v 1.2 2013/06/20 05:30:21 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/gtmr_var.h>
#include <arm/cortex/mpcore_var.h>
static int gtmr_match(device_t, cfdata_t, void *);
static void gtmr_attach(device_t, device_t, void *);
static int clockhandler(void *);
static u_int gtmr_get_timecount(struct timecounter *);
static struct gtmr_softc gtmr_sc;
static struct timecounter gtmr_timecounter = {
.tc_get_timecount = gtmr_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 = &gtmr_sc,
.tc_next = NULL,
};
CFATTACH_DECL_NEW(armgtmr, 0, gtmr_match, gtmr_attach, NULL, NULL);
/* ARGSUSED */
static int
gtmr_match(device_t parent, cfdata_t cf, void *aux)
{
struct mpcore_attach_args * const mpcaa = aux;
if (gtmr_sc.sc_dev != NULL)
return 0;
if ((armreg_pfr1_read() & ARM_PFR1_GTIMER_MASK) == 0)
return 0;
if (strcmp(mpcaa->mpcaa_name, cf->cf_name) != 0)
return 0;
return 1;
}
static void
gtmr_attach(device_t parent, device_t self, void *aux)
{
struct gtmr_softc *sc = &gtmr_sc;
prop_dictionary_t dict = device_properties(self);
char freqbuf[sizeof("X.XXX SHz")];
/*
* This runs at a fixed frequency of 1 to 50MHz.
*/
prop_dictionary_get_uint32(dict, "frequency", &sc->sc_freq);
humanize_number(freqbuf, sizeof(freqbuf), sc->sc_freq, "Hz", 1000);
aprint_naive("\n");
aprint_normal(": ARMv7 Generic 64-bit Timer (%s)\n", freqbuf);
/*
* Enable the virtual counter to be accessed from usermode.
*/
armreg_cntk_ctl_write(armreg_cntk_ctl_read() | ARM_CNTKCTL_PL0VCTEN);
self->dv_private = sc;
sc->sc_dev = self;
evcnt_attach_dynamic(&sc->sc_ev_missing_ticks, EVCNT_TYPE_MISC, NULL,
device_xname(self), "missing interrupts");
sc->sc_global_ih = intr_establish(IRQ_GTMR_PPI_VTIMER, 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_GTMR_PPI_VTIMER);
}
void
gtmr_init_cpu_clock(struct cpu_info *ci)
{
struct gtmr_softc * const sc = &gtmr_sc;
uint64_t now = armreg_cntv_ct_read();
KASSERT(ci == curcpu());
ci->ci_lastintr = now;
/*
* Schedule the next interrupt.
*/
now += sc->sc_autoinc;
armreg_cntv_tval_write(sc->sc_autoinc);
/*
* enable timer and stop masking the timer.
*/
armreg_cntv_ctl_write(ARM_CNTCTL_ENABLE);
#if 0
printf("%s: %s: ctl %#x cmp %#"PRIx64" now %#"PRIx64"\n",
__func__, ci->ci_data.cpu_name, armreg_cntv_ctl_read(),
armreg_cntv_cval_read(), armreg_cntv_ct_read());
int s = splsched();
uint64_t when = now;
u_int n = 0;
while ((now = armreg_cntv_ct_read()) < 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 %#"PRIx64" now %#"PRIx64"\n",
__func__, ci->ci_data.cpu_name, armreg_cntv_ctl_read(),
armreg_cntv_cval_read(), armreg_cntv_ct_read());
splx(s);
#elif 0
delay(1000000 / hz + 1000);
#endif
}
void
cpu_initclocks(void)
{
struct gtmr_softc * const sc = &gtmr_sc;
KASSERT(sc->sc_dev != NULL);
KASSERT(sc->sc_freq != 0);
sc->sc_autoinc = sc->sc_freq / hz;
gtmr_init_cpu_clock(curcpu());
gtmr_timecounter.tc_name = device_xname(sc->sc_dev);
gtmr_timecounter.tc_frequency = sc->sc_freq;
tc_init(&gtmr_timecounter);
}
void
gtmr_delay(unsigned int n)
{
struct gtmr_softc * const sc = &gtmr_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 = armreg_cntv_ct_read();
const uint64_t finish = base + delta;
while (armreg_cntv_ct_read() < finish) {
/* spin */
}
}
/*
* clockhandler:
*
* Handle the hardclock interrupt.
*/
static int
clockhandler(void *arg)
{
struct clockframe * const cf = arg;
struct gtmr_softc * const sc = &gtmr_sc;
struct cpu_info * const ci = curcpu();
const uint64_t now = armreg_cntv_ct_read();
uint64_t delta = now - ci->ci_lastintr;
#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);
/*
* If we got interrutped too soon (delta < sc->sc_autoinc) or
* we missed a tick (delta >= 2 * sc->sc_autoinc), don't try to
* adjust for jitter.
*/
if (delta < sc->sc_autoinc || delta >= 2 * sc->sc_autoinc) {
delta = 0;
}
armreg_cntv_tval_write(sc->sc_autoinc - delta);
ci->ci_lastintr = now;
hardclock(cf);
if (delta > 2 * sc->sc_autoinc)
sc->sc_ev_missing_ticks.ev_count += (delta / sc->sc_autoinc) - 1;
return 1;
}
void
setstatclockrate(int newhz)
{
}
static u_int
gtmr_get_timecount(struct timecounter *tc)
{
return (u_int) (armreg_cntv_ct_read());
}