2 * Copyright (c) 2015-2017 Ruslan Bukin <br@bsdpad.com>
5 * Portions of this software were developed by SRI International and the
6 * University of Cambridge Computer Laboratory under DARPA/AFRL contract
7 * FA8750-10-C-0237 ("CTSRD"), as part of the DARPA CRASH research programme.
9 * Portions of this software were developed by the University of Cambridge
10 * Computer Laboratory as part of the CTSRD Project, with support from the
11 * UK Higher Education Innovation Fund (HEIF).
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
16 * 1. Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution.
22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
39 #include "opt_platform.h"
41 #include <sys/cdefs.h>
42 __FBSDID("$FreeBSD$");
44 #include <sys/param.h>
45 #include <sys/systm.h>
47 #include <sys/kernel.h>
48 #include <sys/module.h>
49 #include <sys/timeet.h>
50 #include <sys/timetc.h>
52 #include <sys/watchdog.h>
54 #include <machine/cpufunc.h>
55 #include <machine/intr.h>
56 #include <machine/sbi.h>
58 #include <dev/ofw/openfirm.h>
60 struct riscv_timer_softc {
65 static struct riscv_timer_softc *riscv_timer_sc = NULL;
67 static timecounter_get_t riscv_timer_tc_get_timecount;
68 static timecounter_fill_vdso_timehands_t riscv_timer_tc_fill_vdso_timehands;
70 static struct timecounter riscv_timer_timecount = {
71 .tc_name = "RISC-V Timecounter",
72 .tc_get_timecount = riscv_timer_tc_get_timecount,
74 .tc_counter_mask = ~0u,
77 .tc_fill_vdso_timehands = riscv_timer_tc_fill_vdso_timehands,
80 static inline uint64_t
88 get_counts(struct riscv_timer_softc *sc)
92 counts = get_cycles();
98 riscv_timer_tc_get_timecount(struct timecounter *tc)
100 struct riscv_timer_softc *sc;
104 return (get_counts(sc));
108 riscv_timer_tc_fill_vdso_timehands(struct vdso_timehands *vdso_th,
109 struct timecounter *tc)
111 vdso_th->th_algo = VDSO_TH_ALGO_RISCV_RDTIME;
112 bzero(vdso_th->th_res, sizeof(vdso_th->th_res));
117 riscv_timer_et_start(struct eventtimer *et, sbintime_t first, sbintime_t period)
122 counts = ((uint32_t)et->et_frequency * first) >> 32;
123 sbi_set_timer(get_cycles() + counts);
124 csr_set(sie, SIE_STIE);
133 riscv_timer_et_stop(struct eventtimer *et)
136 /* Disable timer interrupts. */
137 csr_clear(sie, SIE_STIE);
143 riscv_timer_intr(void *arg)
145 struct riscv_timer_softc *sc;
147 sc = (struct riscv_timer_softc *)arg;
149 csr_clear(sip, SIP_STIP);
151 if (sc->et.et_active)
152 sc->et.et_event_cb(&sc->et, sc->et.et_arg);
154 return (FILTER_HANDLED);
158 riscv_timer_get_timebase(device_t dev, uint32_t *freq)
163 node = OF_finddevice("/cpus");
166 device_printf(dev, "Can't find cpus node.\n");
170 len = OF_getproplen(node, "timebase-frequency");
174 "Can't find timebase-frequency property.\n");
178 OF_getencprop(node, "timebase-frequency", freq, len);
184 riscv_timer_probe(device_t dev)
187 device_set_desc(dev, "RISC-V Timer");
189 return (BUS_PROBE_DEFAULT);
193 riscv_timer_attach(device_t dev)
195 struct riscv_timer_softc *sc;
198 sc = device_get_softc(dev);
199 if (riscv_timer_sc != NULL)
202 if (device_get_unit(dev) != 0)
205 if (riscv_timer_get_timebase(dev, &sc->clkfreq) != 0) {
206 device_printf(dev, "No clock frequency specified\n");
212 /* Setup IRQs handler */
213 error = riscv_setup_intr(device_get_nameunit(dev), riscv_timer_intr,
214 NULL, sc, IRQ_TIMER_SUPERVISOR, INTR_TYPE_CLK, &sc->ih);
216 device_printf(dev, "Unable to alloc int resource.\n");
220 riscv_timer_timecount.tc_frequency = sc->clkfreq;
221 riscv_timer_timecount.tc_priv = sc;
222 tc_init(&riscv_timer_timecount);
224 sc->et.et_name = "RISC-V Eventtimer";
225 sc->et.et_flags = ET_FLAGS_ONESHOT | ET_FLAGS_PERCPU;
226 sc->et.et_quality = 1000;
228 sc->et.et_frequency = sc->clkfreq;
229 sc->et.et_min_period = (0x00000002LLU << 32) / sc->et.et_frequency;
230 sc->et.et_max_period = (0xfffffffeLLU << 32) / sc->et.et_frequency;
231 sc->et.et_start = riscv_timer_et_start;
232 sc->et.et_stop = riscv_timer_et_stop;
234 et_register(&sc->et);
236 set_cputicker(get_timecount, sc->clkfreq, false);
241 static device_method_t riscv_timer_methods[] = {
242 DEVMETHOD(device_probe, riscv_timer_probe),
243 DEVMETHOD(device_attach, riscv_timer_attach),
247 static driver_t riscv_timer_driver = {
250 sizeof(struct riscv_timer_softc),
253 static devclass_t riscv_timer_devclass;
255 EARLY_DRIVER_MODULE(timer, nexus, riscv_timer_driver, riscv_timer_devclass,
256 0, 0, BUS_PASS_TIMER + BUS_PASS_ORDER_MIDDLE);
261 int64_t counts, counts_per_usec;
262 uint64_t first, last;
265 * Check the timers are setup, if not just
266 * use a for loop for the meantime
268 if (riscv_timer_sc == NULL) {
269 for (; usec > 0; usec--)
270 for (counts = 200; counts > 0; counts--)
272 * Prevent the compiler from optimizing
280 /* Get the number of times to count */
281 counts_per_usec = ((riscv_timer_timecount.tc_frequency / 1000000) + 1);
284 * Clamp the timeout at a maximum value (about 32 seconds with
285 * a 66MHz clock). *Nobody* should be delay()ing for anywhere
286 * near that length of time and if they are, they should be hung
289 if (usec >= (0x80000000U / counts_per_usec))
290 counts = (0x80000000U / counts_per_usec) - 1;
292 counts = usec * counts_per_usec;
294 first = get_counts(riscv_timer_sc);
297 last = get_counts(riscv_timer_sc);
298 counts -= (int64_t)(last - first);