1/*
2 * SPDX-License-Identifier: BSD-2-Clause
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/param.h>
31#include <sys/systm.h>
32#include <sys/bus.h>
33#include <sys/kernel.h>
34#include <sys/module.h>
35#include <sys/malloc.h>
36#include <sys/rman.h>
37#include <sys/timeet.h>
38#include <sys/timetc.h>
39#include <sys/watchdog.h>
40#include <machine/bus.h>
41#include <machine/cpu.h>
42#include <machine/intr.h>
43#include <machine/machdep.h>
44
45#include <dev/ofw/openfirm.h>
46#include <dev/ofw/ofw_bus.h>
47#include <dev/ofw/ofw_bus_subr.h>
48
49#include <machine/bus.h>
50
51#define	BCM2835_NUM_TIMERS	4
52
53#define	DEFAULT_TIMER		3
54#define	DEFAULT_TIMER_NAME	"BCM2835-3"
55#define	DEFAULT_FREQUENCY	1000000
56#define	MIN_PERIOD		5LLU
57
58#define	SYSTIMER_CS	0x00
59#define	SYSTIMER_CLO	0x04
60#define	SYSTIMER_CHI	0x08
61#define	SYSTIMER_C0	0x0C
62#define	SYSTIMER_C1	0x10
63#define	SYSTIMER_C2	0x14
64#define	SYSTIMER_C3	0x18
65
66struct systimer {
67	int			index;
68	bool			enabled;
69	struct eventtimer	et;
70};
71
72struct bcm_systimer_softc {
73	struct resource*	mem_res;
74	struct resource*	irq_res[BCM2835_NUM_TIMERS];
75	void*			intr_hl[BCM2835_NUM_TIMERS];
76	uint32_t		sysclk_freq;
77	bus_space_tag_t		bst;
78	bus_space_handle_t	bsh;
79	struct systimer		st[BCM2835_NUM_TIMERS];
80};
81
82static struct resource_spec bcm_systimer_irq_spec[] = {
83	{ SYS_RES_IRQ,      0,  RF_ACTIVE },
84	{ SYS_RES_IRQ,      1,  RF_ACTIVE },
85	{ SYS_RES_IRQ,      2,  RF_ACTIVE },
86	{ SYS_RES_IRQ,      3,  RF_ACTIVE },
87	{ -1,               0,  0 }
88};
89
90static struct ofw_compat_data compat_data[] = {
91	{"broadcom,bcm2835-system-timer",	1},
92	{"brcm,bcm2835-system-timer",		1},
93	{NULL,					0}
94};
95
96static struct bcm_systimer_softc *bcm_systimer_sc = NULL;
97
98/* Read/Write macros for Timer used as timecounter */
99#define bcm_systimer_tc_read_4(reg)		\
100	bus_space_read_4(bcm_systimer_sc->bst, \
101		bcm_systimer_sc->bsh, reg)
102
103#define bcm_systimer_tc_write_4(reg, val)	\
104	bus_space_write_4(bcm_systimer_sc->bst, \
105		bcm_systimer_sc->bsh, reg, val)
106
107static unsigned bcm_systimer_tc_get_timecount(struct timecounter *);
108
109static delay_func bcm_systimer_delay;
110
111static struct timecounter bcm_systimer_tc = {
112	.tc_name           = DEFAULT_TIMER_NAME,
113	.tc_get_timecount  = bcm_systimer_tc_get_timecount,
114	.tc_poll_pps       = NULL,
115	.tc_counter_mask   = ~0u,
116	.tc_frequency      = 0,
117	.tc_quality        = 1000,
118};
119
120static unsigned
121bcm_systimer_tc_get_timecount(struct timecounter *tc)
122{
123	if (bcm_systimer_sc == NULL)
124		return (0);
125
126	return bcm_systimer_tc_read_4(SYSTIMER_CLO);
127}
128
129static int
130bcm_systimer_start(struct eventtimer *et, sbintime_t first, sbintime_t period)
131{
132	struct systimer *st = et->et_priv;
133	uint32_t clo, clo1;
134	uint32_t count;
135	register_t s;
136
137	if (first != 0) {
138		count = ((uint32_t)et->et_frequency * first) >> 32;
139
140		s = intr_disable();
141		clo = bcm_systimer_tc_read_4(SYSTIMER_CLO);
142restart:
143		clo += count;
144		/*
145		 * Clear pending interrupts
146		 */
147		bcm_systimer_tc_write_4(SYSTIMER_CS, (1 << st->index));
148		bcm_systimer_tc_write_4(SYSTIMER_C0 + st->index*4, clo);
149		clo1 = bcm_systimer_tc_read_4(SYSTIMER_CLO);
150		if ((int32_t)(clo1 - clo) >= 0) {
151			count *= 2;
152			clo = clo1;
153			goto restart;
154		}
155		st->enabled = 1;
156		intr_restore(s);
157
158		return (0);
159	}
160
161	return (EINVAL);
162}
163
164static int
165bcm_systimer_stop(struct eventtimer *et)
166{
167	struct systimer *st = et->et_priv;
168	st->enabled = 0;
169
170	return (0);
171}
172
173static int
174bcm_systimer_intr(void *arg)
175{
176	struct systimer *st = (struct systimer *)arg;
177	uint32_t cs;
178
179	cs = bcm_systimer_tc_read_4(SYSTIMER_CS);
180	if ((cs & (1 << st->index)) == 0)
181		return (FILTER_STRAY);
182
183	/* ACK interrupt */
184	bcm_systimer_tc_write_4(SYSTIMER_CS, (1 << st->index));
185	if (st->enabled) {
186		if (st->et.et_active) {
187			st->et.et_event_cb(&st->et, st->et.et_arg);
188		}
189	}
190
191	return (FILTER_HANDLED);
192}
193
194static int
195bcm_systimer_probe(device_t dev)
196{
197
198	if (!ofw_bus_status_okay(dev))
199		return (ENXIO);
200
201	if (ofw_bus_search_compatible(dev, compat_data)->ocd_data == 0)
202		return (ENXIO);
203
204	return (BUS_PROBE_DEFAULT);
205}
206
207static int
208bcm_systimer_attach(device_t dev)
209{
210	struct bcm_systimer_softc *sc = device_get_softc(dev);
211	int err;
212	int rid = 0;
213
214	if (bcm_systimer_sc != NULL)
215		return (EINVAL);
216
217	sc->mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid, RF_ACTIVE);
218	if (sc->mem_res == NULL) {
219		device_printf(dev, "could not allocate memory resource\n");
220		return (ENXIO);
221	}
222
223	sc->bst = rman_get_bustag(sc->mem_res);
224	sc->bsh = rman_get_bushandle(sc->mem_res);
225
226	/* Request the IRQ resources */
227	err = bus_alloc_resources(dev, bcm_systimer_irq_spec,
228		sc->irq_res);
229	if (err) {
230		device_printf(dev, "Error: could not allocate irq resources\n");
231		return (ENXIO);
232	}
233
234	/* TODO: get frequency from FDT */
235	sc->sysclk_freq = DEFAULT_FREQUENCY;
236
237	/* Setup and enable the timer */
238	if (bus_setup_intr(dev, sc->irq_res[DEFAULT_TIMER], INTR_TYPE_CLK,
239			bcm_systimer_intr, NULL, &sc->st[DEFAULT_TIMER],
240			&sc->intr_hl[DEFAULT_TIMER]) != 0) {
241		bus_release_resources(dev, bcm_systimer_irq_spec,
242			sc->irq_res);
243		device_printf(dev, "Unable to setup the clock irq handler.\n");
244		return (ENXIO);
245	}
246
247	sc->st[DEFAULT_TIMER].index = DEFAULT_TIMER;
248	sc->st[DEFAULT_TIMER].enabled = 0;
249	sc->st[DEFAULT_TIMER].et.et_name = DEFAULT_TIMER_NAME;
250	sc->st[DEFAULT_TIMER].et.et_flags = ET_FLAGS_ONESHOT;
251	sc->st[DEFAULT_TIMER].et.et_quality = 1000;
252	sc->st[DEFAULT_TIMER].et.et_frequency = sc->sysclk_freq;
253	sc->st[DEFAULT_TIMER].et.et_min_period =
254	    (MIN_PERIOD << 32) / sc->st[DEFAULT_TIMER].et.et_frequency + 1;
255	sc->st[DEFAULT_TIMER].et.et_max_period =
256	    (0x7ffffffeLLU << 32) / sc->st[DEFAULT_TIMER].et.et_frequency;
257	sc->st[DEFAULT_TIMER].et.et_start = bcm_systimer_start;
258	sc->st[DEFAULT_TIMER].et.et_stop = bcm_systimer_stop;
259	sc->st[DEFAULT_TIMER].et.et_priv = &sc->st[DEFAULT_TIMER];
260	et_register(&sc->st[DEFAULT_TIMER].et);
261
262	bcm_systimer_sc = sc;
263
264	if (device_get_unit(dev) == 0)
265		arm_set_delay(bcm_systimer_delay, sc);
266
267	bcm_systimer_tc.tc_frequency = DEFAULT_FREQUENCY;
268	tc_init(&bcm_systimer_tc);
269
270	return (0);
271}
272
273static device_method_t bcm_systimer_methods[] = {
274	DEVMETHOD(device_probe,		bcm_systimer_probe),
275	DEVMETHOD(device_attach,	bcm_systimer_attach),
276	{ 0, 0 }
277};
278
279static driver_t bcm_systimer_driver = {
280	"systimer",
281	bcm_systimer_methods,
282	sizeof(struct bcm_systimer_softc),
283};
284
285DRIVER_MODULE(bcm_systimer, simplebus, bcm_systimer_driver, 0, 0);
286
287static void
288bcm_systimer_delay(int usec, void *arg)
289{
290	int32_t counts;
291	uint32_t first, last;
292
293	/* Get the number of times to count */
294	counts = usec * (bcm_systimer_tc.tc_frequency / 1000000) + 1;
295
296	first = bcm_systimer_tc_read_4(SYSTIMER_CLO);
297
298	while (counts > 0) {
299		last = bcm_systimer_tc_read_4(SYSTIMER_CLO);
300		if (last == first)
301			continue;
302		if (last>first) {
303			counts -= (int32_t)(last - first);
304		} else {
305			counts -= (int32_t)((0xFFFFFFFF - first) + last);
306		}
307		first = last;
308	}
309}
310