1/*-
2 * Copyright (c) 2009 Gallon Sylvestre.  All rights reserved.
3 * Copyright (c) 2010 Greg Ansley.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
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.
13 *
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
24 * SUCH DAMAGE.
25 */
26
27#include "opt_platform.h"
28
29#include <sys/cdefs.h>
30__FBSDID("$FreeBSD: releng/10.2/sys/arm/at91/at91_pit.c 266196 2014-05-15 21:21:47Z ian $");
31
32#include <sys/param.h>
33#include <sys/bus.h>
34#include <sys/kernel.h>
35#include <sys/module.h>
36#include <sys/resource.h>
37#include <sys/systm.h>
38#include <sys/rman.h>
39#include <sys/time.h>
40#include <sys/timetc.h>
41#include <sys/watchdog.h>
42
43#include <machine/bus.h>
44#include <machine/cpu.h>
45#include <machine/cpufunc.h>
46#include <machine/frame.h>
47#include <machine/intr.h>
48#include <machine/resource.h>
49
50#include <arm/at91/at91var.h>
51#include <arm/at91/at91_pitreg.h>
52
53#ifdef FDT
54#include <dev/fdt/fdt_common.h>
55#include <dev/ofw/ofw_bus.h>
56#include <dev/ofw/ofw_bus_subr.h>
57#endif
58
59#ifndef PIT_PRESCALE
60#define PIT_PRESCALE (16)
61#endif
62
63static struct pit_softc {
64	struct resource	*mem_res;	/* Memory resource */
65	void		*intrhand;	/* Interrupt handle */
66	device_t	sc_dev;
67} *sc;
68
69static uint32_t timecount = 0;
70static unsigned at91_pit_get_timecount(struct timecounter *tc);
71static int pit_intr(void *arg);
72
73static inline uint32_t
74RD4(struct pit_softc *sc, bus_size_t off)
75{
76
77	return (bus_read_4(sc->mem_res, off));
78}
79
80static inline void
81WR4(struct pit_softc *sc, bus_size_t off, uint32_t val)
82{
83
84	bus_write_4(sc->mem_res, off, val);
85}
86
87void
88at91_pit_delay(int us)
89{
90	int32_t cnt, last, piv;
91	uint64_t pit_freq;
92	const uint64_t mhz  = 1E6;
93
94	if (sc == NULL)
95		return;
96
97	last = PIT_PIV(RD4(sc, PIT_PIIR));
98
99	/* Max delay ~= 260s. @ 133Mhz */
100	pit_freq = at91_master_clock / PIT_PRESCALE;
101	cnt  = ((pit_freq * us) + (mhz -1)) / mhz;
102	cnt  = (cnt <= 0) ? 1 : cnt;
103
104	while (cnt > 0) {
105		piv = PIT_PIV(RD4(sc, PIT_PIIR));
106			cnt  -= piv - last ;
107		if (piv < last)
108			cnt -= PIT_PIV(~0u) - last;
109		last = piv;
110	}
111}
112
113static struct timecounter at91_pit_timecounter = {
114	at91_pit_get_timecount, /* get_timecount */
115	NULL, /* no poll_pps */
116	0xffffffff, /* counter mask */
117	0 / PIT_PRESCALE, /* frequency */
118	"AT91SAM9 timer", /* name */
119	1000 /* quality */
120};
121
122static int
123at91_pit_probe(device_t dev)
124{
125#ifdef FDT
126	if (!ofw_bus_is_compatible(dev, "atmel,at91sam9260-pit"))
127		return (ENXIO);
128#endif
129	device_set_desc(dev, "AT91SAM9 PIT");
130        return (0);
131}
132
133static int
134at91_pit_attach(device_t dev)
135{
136	void *ih;
137	int rid, err = 0;
138	struct resource *irq;
139
140	sc = device_get_softc(dev);
141	sc->sc_dev = dev;
142
143	rid = 0;
144	sc->mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid,
145	    RF_ACTIVE);
146
147	if (sc->mem_res == NULL)
148		panic("couldn't allocate register resources");
149
150	rid = 0;
151	irq = bus_alloc_resource(dev, SYS_RES_IRQ, &rid, 1, 1, 1,
152	    RF_ACTIVE | RF_SHAREABLE);
153	if (!irq) {
154		device_printf(dev, "could not allocate interrupt resources.\n");
155		err = ENOMEM;
156		goto out;
157	}
158
159	/* Activate the interrupt. */
160	err = bus_setup_intr(dev, irq, INTR_TYPE_CLK, pit_intr, NULL, NULL,
161	    &ih);
162
163	at91_pit_timecounter.tc_frequency =  at91_master_clock / PIT_PRESCALE;
164	tc_init(&at91_pit_timecounter);
165
166	/* Enable the PIT here. */
167	WR4(sc, PIT_MR, PIT_PIV(at91_master_clock / PIT_PRESCALE / hz) |
168	    PIT_EN | PIT_IEN);
169out:
170	return (err);
171}
172
173
174static int
175pit_intr(void *arg)
176{
177	struct trapframe *fp = arg;
178	uint32_t icnt;
179
180	if (RD4(sc, PIT_SR) & PIT_PITS_DONE) {
181		icnt = RD4(sc, PIT_PIVR) >> 20;
182
183		/* Just add in the overflows we just read */
184		timecount +=  PIT_PIV(RD4(sc, PIT_MR)) * icnt;
185
186		hardclock(TRAPF_USERMODE(fp), TRAPF_PC(fp));
187		return (FILTER_HANDLED);
188	}
189	return (FILTER_STRAY);
190}
191
192static unsigned
193at91_pit_get_timecount(struct timecounter *tc)
194{
195	uint32_t piir, icnt;
196
197	piir = RD4(sc, PIT_PIIR); /* Current  count | over flows */
198	icnt = piir >> 20;	/* Overflows */
199	return (timecount + PIT_PIV(piir) + PIT_PIV(RD4(sc, PIT_MR)) * icnt);
200}
201
202static device_method_t at91_pit_methods[] = {
203	DEVMETHOD(device_probe, at91_pit_probe),
204	DEVMETHOD(device_attach, at91_pit_attach),
205	DEVMETHOD_END
206};
207
208static driver_t at91_pit_driver = {
209	"at91_pit",
210	at91_pit_methods,
211	sizeof(struct pit_softc),
212};
213
214static devclass_t at91_pit_devclass;
215
216#ifdef FDT
217DRIVER_MODULE(at91_pit, simplebus, at91_pit_driver, at91_pit_devclass, NULL,
218    NULL);
219#else
220DRIVER_MODULE(at91_pit, atmelarm, at91_pit_driver, at91_pit_devclass, NULL,
221    NULL);
222#endif
223