1/*
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2012 Oleksandr Tymoshenko <gonzo@freebsd.org>
5 * Copyright (c) 2012 Damjan Marion <dmarion@freebsd.org>
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#include <sys/cdefs.h>
31__FBSDID("$FreeBSD$");
32
33#include <sys/param.h>
34#include <sys/systm.h>
35#include <sys/bus.h>
36#include <sys/kernel.h>
37#include <sys/module.h>
38#include <sys/malloc.h>
39#include <sys/rman.h>
40#include <sys/timeet.h>
41#include <sys/timetc.h>
42#include <sys/watchdog.h>
43#include <machine/bus.h>
44#include <machine/cpu.h>
45#include <machine/intr.h>
46#include <machine/machdep.h>
47
48#include <dev/ofw/openfirm.h>
49#include <dev/ofw/ofw_bus.h>
50#include <dev/ofw/ofw_bus_subr.h>
51
52#include <machine/bus.h>
53
54#define	BCM2835_NUM_TIMERS	4
55
56#define	DEFAULT_TIMER		3
57#define	DEFAULT_TIMER_NAME	"BCM2835-3"
58#define	DEFAULT_FREQUENCY	1000000
59#define	MIN_PERIOD		5LLU
60
61#define	SYSTIMER_CS	0x00
62#define	SYSTIMER_CLO	0x04
63#define	SYSTIMER_CHI	0x08
64#define	SYSTIMER_C0	0x0C
65#define	SYSTIMER_C1	0x10
66#define	SYSTIMER_C2	0x14
67#define	SYSTIMER_C3	0x18
68
69struct systimer {
70	int			index;
71	bool			enabled;
72	struct eventtimer	et;
73};
74
75struct bcm_systimer_softc {
76	struct resource*	mem_res;
77	struct resource*	irq_res[BCM2835_NUM_TIMERS];
78	void*			intr_hl[BCM2835_NUM_TIMERS];
79	uint32_t		sysclk_freq;
80	bus_space_tag_t		bst;
81	bus_space_handle_t	bsh;
82	struct systimer		st[BCM2835_NUM_TIMERS];
83};
84
85static struct resource_spec bcm_systimer_irq_spec[] = {
86	{ SYS_RES_IRQ,      0,  RF_ACTIVE },
87	{ SYS_RES_IRQ,      1,  RF_ACTIVE },
88	{ SYS_RES_IRQ,      2,  RF_ACTIVE },
89	{ SYS_RES_IRQ,      3,  RF_ACTIVE },
90	{ -1,               0,  0 }
91};
92
93static struct ofw_compat_data compat_data[] = {
94	{"broadcom,bcm2835-system-timer",	1},
95	{"brcm,bcm2835-system-timer",		1},
96	{NULL,					0}
97};
98
99static struct bcm_systimer_softc *bcm_systimer_sc = NULL;
100
101/* Read/Write macros for Timer used as timecounter */
102#define bcm_systimer_tc_read_4(reg)		\
103	bus_space_read_4(bcm_systimer_sc->bst, \
104		bcm_systimer_sc->bsh, reg)
105
106#define bcm_systimer_tc_write_4(reg, val)	\
107	bus_space_write_4(bcm_systimer_sc->bst, \
108		bcm_systimer_sc->bsh, reg, val)
109
110static unsigned bcm_systimer_tc_get_timecount(struct timecounter *);
111
112static delay_func bcm_systimer_delay;
113
114static struct timecounter bcm_systimer_tc = {
115	.tc_name           = DEFAULT_TIMER_NAME,
116	.tc_get_timecount  = bcm_systimer_tc_get_timecount,
117	.tc_poll_pps       = NULL,
118	.tc_counter_mask   = ~0u,
119	.tc_frequency      = 0,
120	.tc_quality        = 1000,
121};
122
123static unsigned
124bcm_systimer_tc_get_timecount(struct timecounter *tc)
125{
126	if (bcm_systimer_sc == NULL)
127		return (0);
128
129	return bcm_systimer_tc_read_4(SYSTIMER_CLO);
130}
131
132static int
133bcm_systimer_start(struct eventtimer *et, sbintime_t first, sbintime_t period)
134{
135	struct systimer *st = et->et_priv;
136	uint32_t clo, clo1;
137	uint32_t count;
138	register_t s;
139
140	if (first != 0) {
141		count = ((uint32_t)et->et_frequency * first) >> 32;
142
143		s = intr_disable();
144		clo = bcm_systimer_tc_read_4(SYSTIMER_CLO);
145restart:
146		clo += count;
147		/*
148		 * Clear pending interrupts
149		 */
150		bcm_systimer_tc_write_4(SYSTIMER_CS, (1 << st->index));
151		bcm_systimer_tc_write_4(SYSTIMER_C0 + st->index*4, clo);
152		clo1 = bcm_systimer_tc_read_4(SYSTIMER_CLO);
153		if ((int32_t)(clo1 - clo) >= 0) {
154			count *= 2;
155			clo = clo1;
156			goto restart;
157		}
158		st->enabled = 1;
159		intr_restore(s);
160
161		return (0);
162	}
163
164	return (EINVAL);
165}
166
167static int
168bcm_systimer_stop(struct eventtimer *et)
169{
170	struct systimer *st = et->et_priv;
171	st->enabled = 0;
172
173	return (0);
174}
175
176static int
177bcm_systimer_intr(void *arg)
178{
179	struct systimer *st = (struct systimer *)arg;
180	uint32_t cs;
181
182	cs = bcm_systimer_tc_read_4(SYSTIMER_CS);
183	if ((cs & (1 << st->index)) == 0)
184		return (FILTER_STRAY);
185
186	/* ACK interrupt */
187	bcm_systimer_tc_write_4(SYSTIMER_CS, (1 << st->index));
188	if (st->enabled) {
189		if (st->et.et_active) {
190			st->et.et_event_cb(&st->et, st->et.et_arg);
191		}
192	}
193
194	return (FILTER_HANDLED);
195}
196
197static int
198bcm_systimer_probe(device_t dev)
199{
200
201	if (!ofw_bus_status_okay(dev))
202		return (ENXIO);
203
204	if (ofw_bus_search_compatible(dev, compat_data)->ocd_data == 0)
205		return (ENXIO);
206
207	return (BUS_PROBE_DEFAULT);
208}
209
210static int
211bcm_systimer_attach(device_t dev)
212{
213	struct bcm_systimer_softc *sc = device_get_softc(dev);
214	int err;
215	int rid = 0;
216
217	if (bcm_systimer_sc != NULL)
218		return (EINVAL);
219
220	sc->mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid, RF_ACTIVE);
221	if (sc->mem_res == NULL) {
222		device_printf(dev, "could not allocate memory resource\n");
223		return (ENXIO);
224	}
225
226	sc->bst = rman_get_bustag(sc->mem_res);
227	sc->bsh = rman_get_bushandle(sc->mem_res);
228
229	/* Request the IRQ resources */
230	err = bus_alloc_resources(dev, bcm_systimer_irq_spec,
231		sc->irq_res);
232	if (err) {
233		device_printf(dev, "Error: could not allocate irq resources\n");
234		return (ENXIO);
235	}
236
237	/* TODO: get frequency from FDT */
238	sc->sysclk_freq = DEFAULT_FREQUENCY;
239
240	/* Setup and enable the timer */
241	if (bus_setup_intr(dev, sc->irq_res[DEFAULT_TIMER], INTR_TYPE_CLK,
242			bcm_systimer_intr, NULL, &sc->st[DEFAULT_TIMER],
243			&sc->intr_hl[DEFAULT_TIMER]) != 0) {
244		bus_release_resources(dev, bcm_systimer_irq_spec,
245			sc->irq_res);
246		device_printf(dev, "Unable to setup the clock irq handler.\n");
247		return (ENXIO);
248	}
249
250	sc->st[DEFAULT_TIMER].index = DEFAULT_TIMER;
251	sc->st[DEFAULT_TIMER].enabled = 0;
252	sc->st[DEFAULT_TIMER].et.et_name = DEFAULT_TIMER_NAME;
253	sc->st[DEFAULT_TIMER].et.et_flags = ET_FLAGS_ONESHOT;
254	sc->st[DEFAULT_TIMER].et.et_quality = 1000;
255	sc->st[DEFAULT_TIMER].et.et_frequency = sc->sysclk_freq;
256	sc->st[DEFAULT_TIMER].et.et_min_period =
257	    (MIN_PERIOD << 32) / sc->st[DEFAULT_TIMER].et.et_frequency + 1;
258	sc->st[DEFAULT_TIMER].et.et_max_period =
259	    (0x7ffffffeLLU << 32) / sc->st[DEFAULT_TIMER].et.et_frequency;
260	sc->st[DEFAULT_TIMER].et.et_start = bcm_systimer_start;
261	sc->st[DEFAULT_TIMER].et.et_stop = bcm_systimer_stop;
262	sc->st[DEFAULT_TIMER].et.et_priv = &sc->st[DEFAULT_TIMER];
263	et_register(&sc->st[DEFAULT_TIMER].et);
264
265	bcm_systimer_sc = sc;
266
267	if (device_get_unit(dev) == 0)
268		arm_set_delay(bcm_systimer_delay, sc);
269
270	bcm_systimer_tc.tc_frequency = DEFAULT_FREQUENCY;
271	tc_init(&bcm_systimer_tc);
272
273	return (0);
274}
275
276static device_method_t bcm_systimer_methods[] = {
277	DEVMETHOD(device_probe,		bcm_systimer_probe),
278	DEVMETHOD(device_attach,	bcm_systimer_attach),
279	{ 0, 0 }
280};
281
282static driver_t bcm_systimer_driver = {
283	"systimer",
284	bcm_systimer_methods,
285	sizeof(struct bcm_systimer_softc),
286};
287
288static devclass_t bcm_systimer_devclass;
289
290DRIVER_MODULE(bcm_systimer, simplebus, bcm_systimer_driver, bcm_systimer_devclass, 0, 0);
291
292static void
293bcm_systimer_delay(int usec, void *arg)
294{
295	struct bcm_systimer_softc *sc;
296	int32_t counts;
297	uint32_t first, last;
298
299	sc = (struct bcm_systimer_softc *) arg;
300
301	/* Get the number of times to count */
302	counts = usec * (bcm_systimer_tc.tc_frequency / 1000000) + 1;
303
304	first = bcm_systimer_tc_read_4(SYSTIMER_CLO);
305
306	while (counts > 0) {
307		last = bcm_systimer_tc_read_4(SYSTIMER_CLO);
308		if (last == first)
309			continue;
310		if (last>first) {
311			counts -= (int32_t)(last - first);
312		} else {
313			counts -= (int32_t)((0xFFFFFFFF - first) + last);
314		}
315		first = last;
316	}
317}
318