2 * Copyright (c) 2012 Oleksandr Tymoshenko <gonzo@freebsd.org>
3 * Copyright (c) 2012 Damjan Marion <dmarion@freebsd.org>
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 #include <sys/cdefs.h>
29 __FBSDID("$FreeBSD$");
31 #include <sys/param.h>
32 #include <sys/systm.h>
34 #include <sys/kernel.h>
35 #include <sys/module.h>
36 #include <sys/malloc.h>
38 #include <sys/timeet.h>
39 #include <sys/timetc.h>
40 #include <sys/watchdog.h>
41 #include <machine/bus.h>
42 #include <machine/cpu.h>
43 #include <machine/intr.h>
45 #include <dev/fdt/fdt_common.h>
46 #include <dev/ofw/openfirm.h>
47 #include <dev/ofw/ofw_bus.h>
48 #include <dev/ofw/ofw_bus_subr.h>
50 #include <machine/bus.h>
51 #include <machine/fdt.h>
53 #define BCM2835_NUM_TIMERS 4
55 #define DEFAULT_TIMER 3
56 #define DEFAULT_FREQUENCY 1000000
57 #define MIN_PERIOD 5LLU
59 #define SYSTIMER_CS 0x00
60 #define SYSTIMER_CLO 0x04
61 #define SYSTIMER_CHI 0x08
62 #define SYSTIMER_C0 0x0C
63 #define SYSTIMER_C1 0x10
64 #define SYSTIMER_C2 0x14
65 #define SYSTIMER_C3 0x18
73 struct bcm_systimer_softc {
74 struct resource* mem_res;
75 struct resource* irq_res[BCM2835_NUM_TIMERS];
76 void* intr_hl[BCM2835_NUM_TIMERS];
79 bus_space_handle_t bsh;
80 struct systimer st[BCM2835_NUM_TIMERS];
83 static struct resource_spec bcm_systimer_irq_spec[] = {
84 { SYS_RES_IRQ, 0, RF_ACTIVE },
85 { SYS_RES_IRQ, 1, RF_ACTIVE },
86 { SYS_RES_IRQ, 2, RF_ACTIVE },
87 { SYS_RES_IRQ, 3, RF_ACTIVE },
91 static struct bcm_systimer_softc *bcm_systimer_sc = NULL;
93 /* Read/Write macros for Timer used as timecounter */
94 #define bcm_systimer_tc_read_4(reg) \
95 bus_space_read_4(bcm_systimer_sc->bst, \
96 bcm_systimer_sc->bsh, reg)
98 #define bcm_systimer_tc_write_4(reg, val) \
99 bus_space_write_4(bcm_systimer_sc->bst, \
100 bcm_systimer_sc->bsh, reg, val)
102 static unsigned bcm_systimer_tc_get_timecount(struct timecounter *);
104 static struct timecounter bcm_systimer_tc = {
105 .tc_name = "BCM2835 Timecounter",
106 .tc_get_timecount = bcm_systimer_tc_get_timecount,
108 .tc_counter_mask = ~0u,
114 bcm_systimer_tc_get_timecount(struct timecounter *tc)
116 return bcm_systimer_tc_read_4(SYSTIMER_CLO);
120 bcm_systimer_start(struct eventtimer *et, sbintime_t first, sbintime_t period)
122 struct systimer *st = et->et_priv;
129 count = ((uint32_t)et->et_frequency * first) >> 32;
132 clo = bcm_systimer_tc_read_4(SYSTIMER_CLO);
136 * Clear pending interrupts
138 bcm_systimer_tc_write_4(SYSTIMER_CS, (1 << st->index));
139 bcm_systimer_tc_write_4(SYSTIMER_C0 + st->index*4, clo);
140 clo1 = bcm_systimer_tc_read_4(SYSTIMER_CLO);
141 if ((int32_t)(clo1 - clo) >= 0) {
156 bcm_systimer_stop(struct eventtimer *et)
158 struct systimer *st = et->et_priv;
165 bcm_systimer_intr(void *arg)
167 struct systimer *st = (struct systimer *)arg;
170 cs = bcm_systimer_tc_read_4(SYSTIMER_CS);
171 if ((cs & (1 << st->index)) == 0)
172 return (FILTER_STRAY);
175 bcm_systimer_tc_write_4(SYSTIMER_CS, (1 << st->index));
177 if (st->et.et_active) {
178 st->et.et_event_cb(&st->et, st->et.et_arg);
182 return (FILTER_HANDLED);
186 bcm_systimer_probe(device_t dev)
189 if (!ofw_bus_status_okay(dev))
192 if (ofw_bus_is_compatible(dev, "broadcom,bcm2835-system-timer")) {
193 device_set_desc(dev, "BCM2835 System Timer");
194 return (BUS_PROBE_DEFAULT);
201 bcm_systimer_attach(device_t dev)
203 struct bcm_systimer_softc *sc = device_get_softc(dev);
207 if (bcm_systimer_sc != NULL)
210 sc->mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid, RF_ACTIVE);
211 if (sc->mem_res == NULL) {
212 device_printf(dev, "could not allocate memory resource\n");
216 sc->bst = rman_get_bustag(sc->mem_res);
217 sc->bsh = rman_get_bushandle(sc->mem_res);
219 /* Request the IRQ resources */
220 err = bus_alloc_resources(dev, bcm_systimer_irq_spec,
223 device_printf(dev, "Error: could not allocate irq resources\n");
227 /* TODO: get frequency from FDT */
228 sc->sysclk_freq = DEFAULT_FREQUENCY;
230 /* Setup and enable the timer */
231 if (bus_setup_intr(dev, sc->irq_res[DEFAULT_TIMER], INTR_TYPE_CLK,
232 bcm_systimer_intr, NULL, &sc->st[DEFAULT_TIMER],
233 &sc->intr_hl[DEFAULT_TIMER]) != 0) {
234 bus_release_resources(dev, bcm_systimer_irq_spec,
236 device_printf(dev, "Unable to setup the clock irq handler.\n");
240 sc->st[DEFAULT_TIMER].index = DEFAULT_TIMER;
241 sc->st[DEFAULT_TIMER].enabled = 0;
242 sc->st[DEFAULT_TIMER].et.et_name = malloc(64, M_DEVBUF, M_NOWAIT | M_ZERO);
243 sprintf(sc->st[DEFAULT_TIMER].et.et_name, "BCM2835 Event Timer %d", DEFAULT_TIMER);
244 sc->st[DEFAULT_TIMER].et.et_flags = ET_FLAGS_ONESHOT;
245 sc->st[DEFAULT_TIMER].et.et_quality = 1000;
246 sc->st[DEFAULT_TIMER].et.et_frequency = sc->sysclk_freq;
247 sc->st[DEFAULT_TIMER].et.et_min_period =
248 (MIN_PERIOD << 32) / sc->st[DEFAULT_TIMER].et.et_frequency + 1;
249 sc->st[DEFAULT_TIMER].et.et_max_period =
250 (0x7ffffffeLLU << 32) / sc->st[DEFAULT_TIMER].et.et_frequency;
251 sc->st[DEFAULT_TIMER].et.et_start = bcm_systimer_start;
252 sc->st[DEFAULT_TIMER].et.et_stop = bcm_systimer_stop;
253 sc->st[DEFAULT_TIMER].et.et_priv = &sc->st[DEFAULT_TIMER];
254 et_register(&sc->st[DEFAULT_TIMER].et);
256 bcm_systimer_sc = sc;
258 bcm_systimer_tc.tc_frequency = DEFAULT_FREQUENCY;
259 tc_init(&bcm_systimer_tc);
264 static device_method_t bcm_systimer_methods[] = {
265 DEVMETHOD(device_probe, bcm_systimer_probe),
266 DEVMETHOD(device_attach, bcm_systimer_attach),
270 static driver_t bcm_systimer_driver = {
272 bcm_systimer_methods,
273 sizeof(struct bcm_systimer_softc),
276 static devclass_t bcm_systimer_devclass;
278 DRIVER_MODULE(bcm_systimer, simplebus, bcm_systimer_driver, bcm_systimer_devclass, 0, 0);
284 uint32_t first, last;
286 if (bcm_systimer_sc == NULL) {
287 for (; usec > 0; usec--)
288 for (counts = 200; counts > 0; counts--)
289 /* Prevent gcc from optimizing out the loop */
294 /* Get the number of times to count */
295 counts = usec * (bcm_systimer_tc.tc_frequency / 1000000) + 1;
297 first = bcm_systimer_tc_read_4(SYSTIMER_CLO);
300 last = bcm_systimer_tc_read_4(SYSTIMER_CLO);
304 counts -= (int32_t)(last - first);
306 counts -= (int32_t)((0xFFFFFFFF - first) + last);