/* $NetBSD: a64gtmr.c,v 1.1 2014/08/10 05:47:37 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 __KERNEL_RCSID(0, "$NetBSD: a64gtmr.c,v 1.1 2014/08/10 05:47:37 matt Exp $"); #include "locators.h" #include #include #include #include #include #include #include #include #include #include #include #include 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; struct gtmr_percpu { uint32_t pc_delta; }; 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 = >mr_sc, .tc_next = NULL, }; CFATTACH_DECL_NEW(a64gtmr, 0, gtmr_match, gtmr_attach, NULL, NULL); /* ARGSUSED */ static int gtmr_match(device_t parent, cfdata_t cf, void *aux) { struct mainbus_attach_args * const mba = aux; if (gtmr_sc.sc_dev != NULL) return 0; if (strcmp(mba->mba_name, cf->cf_name) != 0) return 0; return 1; } static void gtmr_attach(device_t parent, device_t self, void *aux) { const struct mainbus_attach_args * const mba = aux; struct gtmr_softc *sc = >mr_sc; prop_dictionary_t dict = device_properties(self); char freqbuf[sizeof("X.XXX SHz")]; uint32_t irq; if (mba->mba_intr == MAINBUSCF_INTR_DEFAULT) { prop_dictionary_get_uint32(dict, "intr", &irq); } else { irq = mba->mba_intr; } /* * 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(": ARMv8 Generic 64-bit Timer (%s)\n", freqbuf); /* * Enable the virtual counter to be accessed from usermode. */ reg_cntkctl_el1_write(reg_cntkctl_el1_read() | CNTKCTL_EL0VCTEN); self->dv_private = sc; sc->sc_dev = self; #ifdef DIAGNOSTIC sc->sc_percpu = percpu_alloc(sizeof(struct gtmr_percpu)); #endif evcnt_attach_dynamic(&sc->sc_ev_missing_ticks, EVCNT_TYPE_MISC, NULL, device_xname(self), "missing interrupts"); sc->sc_global_ih = intr_establish(irq, IPL_CLOCK, IST_LEVEL, clockhandler, NULL); if (sc->sc_global_ih == NULL) panic("%s: unable to register timer interrupt", __func__); aprint_normal_dev(self, "interrupting on irq %d\n", irq); const uint32_t cnt_frq = reg_cntfrq_el0_read(); if (cnt_frq == 0) { aprint_verbose_dev(self, "CNTFRQ_EL0 not set\n"); } else if (cnt_frq != sc->sc_freq) { aprint_verbose_dev(self, "CNTFRQ_EL0 (%u) differs from supplied frequency\n", cnt_frq); } } void gtmr_init_cpu_clock(struct cpu_info *ci) { struct gtmr_softc * const sc = >mr_sc; KASSERT(ci == curcpu()); int s = splsched(); /* * enable timer and stop masking the timer. */ reg_cntv_ctl_el0_write(CNTCTL_ENABLE); /* * Get now and update the compare timer. */ ci->ci_lastintr = reg_cntvct_el0_read(); reg_cntv_tval_el0_write(sc->sc_autoinc); #if 0 printf("%s: %s: delta cval = %"PRIu64"\n", __func__, ci->ci_data.cpu_name, reg_cntv_cval_el1_read() - ci->ci_lastintr); #endif splx(s); #if 0 printf("%s: %s: ctl %#x cmp %#"PRIx64" now %#"PRIx64"\n", __func__, ci->ci_data.cpu_name, reg_cntv_ctl_el0_read(), reg_cntv_cval_el0_read(), reg_cntvct_el0_read()); s = splsched(); uint64_t now64; uint64_t start64 = reg_cntvct_el0_read(); do { now64 = reg_cntvct_el0_read(); } while (start64 == now64); start64 = now64; uint64_t end64 = start64 + 64; uint32_t start32 = reg_pmccntr_read(); do { now64 = reg_cntvct_el0_read(); } while (end64 != now64); uint32_t end32 = reg_pmccntr_read(); uint32_t diff32 = end64 - start64; printf("%s: %s: %u cycles per tick\n", __func__, ci->ci_data.cpu_name, (end32 - start32) / diff32); printf("%s: %s: status %#x cmp %#"PRIx64" now %#"PRIx64"\n", __func__, ci->ci_data.cpu_name, reg_cntv_ctl_el0_read(), reg_cntv_cval_el0_read(), reg_cntvct_el0_read()); splx(s); #elif 0 delay(1000000 / hz + 1000); #endif } void cpu_initclocks(void) { struct gtmr_softc * const sc = >mr_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(>mr_timecounter); } void delay(unsigned long n) { struct gtmr_softc * const sc = >mr_sc; KASSERT(sc != NULL); uint32_t freq = sc->sc_freq ? sc->sc_freq : reg_cntfrq_el0_read(); 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 = reg_cntvct_el0_read(); const uint64_t finish = base + delta; while (reg_cntvct_el0_read() < finish) { /* spin */ } } /* * clockhandler: * * Handle the hardclock interrupt. */ static int clockhandler(void *arg) { const uint64_t now = reg_cntvct_el0_read(); struct cpu_info * const ci = curcpu(); uint64_t delta = now - ci->ci_lastintr; struct clockframe * const cf = arg; struct gtmr_softc * const sc = >mr_sc; #ifdef DIAGNOSTIC const uint64_t then = reg_cntv_cval_el0_read(); struct gtmr_percpu * const pc = percpu_getref(sc->sc_percpu); KASSERTMSG(then <= now, "%"PRId64, now - then); KASSERTMSG(then + pc->pc_delta >= ci->ci_lastintr + sc->sc_autoinc, "%"PRId64, then + pc->pc_delta - ci->ci_lastintr - sc->sc_autoinc); #endif #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") autoinc=%lu", ci->ci_data.cpu_name, delta, sc->sc_autoinc); /* * If we got interrupted too soon (delta < sc->sc_autoinc) or * we missed a tick (delta >= 2 * sc->sc_autoinc), don't try to * adjust for jitter. */ delta -= sc->sc_autoinc; if (delta >= sc->sc_autoinc) { delta = 0; } reg_cntv_tval_el0_write(sc->sc_autoinc - delta); ci->ci_lastintr = now; #ifdef DIAGNOSTIC KASSERT(delta == (uint32_t) delta); pc->pc_delta = delta; percpu_putref(sc->sc_percpu); #endif hardclock(cf); sc->sc_ev_missing_ticks.ev_count += delta / sc->sc_autoinc; return 1; } void setstatclockrate(int newhz) { } static u_int gtmr_get_timecount(struct timecounter *tc) { return (u_int) (reg_cntvct_el0_read()); }