2 * Copyright (c) 2009 Gallon Sylvestre. All rights reserved.
3 * Copyright (c) 2010 Greg Ansley. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
30 #include <sys/param.h>
32 #include <sys/kernel.h>
33 #include <sys/module.h>
34 #include <sys/resource.h>
35 #include <sys/systm.h>
38 #include <sys/timetc.h>
39 #include <sys/watchdog.h>
41 #include <machine/bus.h>
42 #include <machine/cpu.h>
43 #include <machine/cpufunc.h>
44 #include <machine/frame.h>
45 #include <machine/intr.h>
46 #include <machine/resource.h>
48 #include <arm/at91/at91var.h>
49 #include <arm/at91/at91_pitreg.h>
52 #define PIT_PRESCALE (16)
55 static struct pit_softc {
56 struct resource *mem_res; /* Memory resource */
57 void *intrhand; /* Interrupt handle */
61 static uint32_t timecount = 0;
62 static unsigned at91_pit_get_timecount(struct timecounter *tc);
63 static int pit_intr(void *arg);
65 static inline uint32_t
66 RD4(struct pit_softc *sc, bus_size_t off)
69 return (bus_read_4(sc->mem_res, off));
73 WR4(struct pit_softc *sc, bus_size_t off, uint32_t val)
76 bus_write_4(sc->mem_res, off, val);
80 at91_pit_delay(int us)
82 int32_t cnt, last, piv;
84 const uint64_t mhz = 1E6;
86 last = PIT_PIV(RD4(sc, PIT_PIIR));
88 /* Max delay ~= 260s. @ 133Mhz */
89 pit_freq = at91_master_clock / PIT_PRESCALE;
90 cnt = ((pit_freq * us) + (mhz -1)) / mhz;
91 cnt = (cnt <= 0) ? 1 : cnt;
94 piv = PIT_PIV(RD4(sc, PIT_PIIR));
97 cnt -= PIT_PIV(~0u) - last;
102 static struct timecounter at91_pit_timecounter = {
103 at91_pit_get_timecount, /* get_timecount */
104 NULL, /* no poll_pps */
105 0xffffffff, /* counter mask */
106 0 / PIT_PRESCALE, /* frequency */
107 "AT91SAM9 timer", /* name */
112 at91_pit_probe(device_t dev)
115 device_set_desc(dev, "AT91SAM9 PIT");
120 at91_pit_attach(device_t dev)
124 struct at91_softc *at91_sc;
125 struct resource *irq;
127 at91_sc = device_get_softc(device_get_parent(dev));
128 sc = device_get_softc(dev);
132 sc->mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid,
135 if (sc->mem_res == NULL)
136 panic("couldn't allocate register resources");
139 irq = bus_alloc_resource(dev, SYS_RES_IRQ, &rid, 1, 1, 1,
140 RF_ACTIVE | RF_SHAREABLE);
142 device_printf(dev, "could not allocate interrupt resources.\n");
147 /* Activate the interrupt. */
148 err = bus_setup_intr(dev, irq, INTR_TYPE_CLK, pit_intr, NULL, NULL,
151 at91_pit_timecounter.tc_frequency = at91_master_clock / PIT_PRESCALE;
152 tc_init(&at91_pit_timecounter);
154 /* Enable the PIT here. */
155 WR4(sc, PIT_MR, PIT_PIV(at91_master_clock / PIT_PRESCALE / hz) |
161 static device_method_t at91_pit_methods[] = {
162 DEVMETHOD(device_probe, at91_pit_probe),
163 DEVMETHOD(device_attach, at91_pit_attach),
167 static driver_t at91_pit_driver = {
170 sizeof(struct pit_softc),
173 static devclass_t at91_pit_devclass;
175 DRIVER_MODULE(at91_pit, atmelarm, at91_pit_driver, at91_pit_devclass, NULL,
181 struct trapframe *fp = arg;
184 if (RD4(sc, PIT_SR) & PIT_PITS_DONE) {
185 icnt = RD4(sc, PIT_PIVR) >> 20;
187 /* Just add in the overflows we just read */
188 timecount += PIT_PIV(RD4(sc, PIT_MR)) * icnt;
190 hardclock(TRAPF_USERMODE(fp), TRAPF_PC(fp));
191 return (FILTER_HANDLED);
193 return (FILTER_STRAY);
197 at91_pit_get_timecount(struct timecounter *tc)
201 piir = RD4(sc, PIT_PIIR); /* Current count | over flows */
202 icnt = piir >> 20; /* Overflows */
203 return (timecount + PIT_PIV(piir) + PIT_PIV(RD4(sc, PIT_MR)) * icnt);