1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2017 Poul-Henning Kamp <phk@FreeBSD.org>
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
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.
14 *
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
25 * SUCH DAMAGE.
26 *
27 */
28
29#include <sys/cdefs.h>
30__FBSDID("$FreeBSD$");
31
32#include <sys/param.h>
33#include <sys/systm.h>
34#include <sys/bus.h>
35#include <sys/cpu.h>
36#include <sys/kernel.h>
37#include <sys/lock.h>
38#include <sys/malloc.h>
39#include <sys/module.h>
40#include <sys/mutex.h>
41#include <sys/rman.h>
42#include <sys/sema.h>
43#include <sys/sysctl.h>
44
45#include <machine/bus.h>
46#include <machine/cpu.h>
47
48#include <dev/ofw/ofw_bus.h>
49#include <dev/ofw/ofw_bus_subr.h>
50
51#include <arm/broadcom/bcm2835/bcm2835_clkman.h>
52
53static struct ofw_compat_data compat_data[] = {
54	{"brcm,bcm2835-cprman",		1},
55	{"broadcom,bcm2835-cprman",	1},
56	{NULL,				0}
57};
58
59struct bcm2835_clkman_softc {
60	device_t		sc_dev;
61
62	struct resource *	sc_m_res;
63	bus_space_tag_t		sc_m_bst;
64	bus_space_handle_t	sc_m_bsh;
65};
66
67#define BCM_CLKMAN_WRITE(_sc, _off, _val)              \
68    bus_space_write_4(_sc->sc_m_bst, _sc->sc_m_bsh, _off, _val)
69#define BCM_CLKMAN_READ(_sc, _off)                     \
70    bus_space_read_4(_sc->sc_m_bst, _sc->sc_m_bsh, _off)
71
72#define W_CMCLK(_sc, unit, _val) BCM_CLKMAN_WRITE(_sc, unit, 0x5a000000 | (_val))
73#define R_CMCLK(_sc, unit) BCM_CLKMAN_READ(_sc, unit)
74#define W_CMDIV(_sc, unit, _val) BCM_CLKMAN_WRITE(_sc, (unit) + 4, 0x5a000000 | (_val))
75#define R_CMDIV(_sc,  unit) BCM_CLKMAN_READ(_sc, (unit) + 4)
76
77static int
78bcm2835_clkman_probe(device_t dev)
79{
80
81	if (!ofw_bus_status_okay(dev))
82		return (ENXIO);
83
84	if (ofw_bus_search_compatible(dev, compat_data)->ocd_data == 0)
85		return (ENXIO);
86
87	device_set_desc(dev, "BCM283x Clock Manager");
88
89	return (BUS_PROBE_DEFAULT);
90}
91
92static int
93bcm2835_clkman_attach(device_t dev)
94{
95	struct bcm2835_clkman_softc *sc;
96	int rid;
97
98	if (device_get_unit(dev) != 0) {
99		device_printf(dev, "only one clk manager supported\n");
100		return (ENXIO);
101	}
102
103	sc = device_get_softc(dev);
104	sc->sc_dev = dev;
105
106	rid = 0;
107	sc->sc_m_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid,
108	    RF_ACTIVE);
109	if (!sc->sc_m_res) {
110		device_printf(dev, "cannot allocate memory window\n");
111		return (ENXIO);
112	}
113
114	sc->sc_m_bst = rman_get_bustag(sc->sc_m_res);
115	sc->sc_m_bsh = rman_get_bushandle(sc->sc_m_res);
116
117	return (bus_generic_attach(dev));
118}
119
120uint32_t
121bcm2835_clkman_set_frequency(device_t dev, uint32_t unit, uint32_t hz)
122{
123	struct bcm2835_clkman_softc *sc;
124	int i;
125	uint32_t u;
126
127	sc = device_get_softc(dev);
128
129	if (unit != BCM_PWM_CLKSRC) {
130		device_printf(sc->sc_dev,
131		    "Unsupported unit 0x%x", unit);
132		return (0);
133	}
134
135	W_CMCLK(sc, unit, 6);
136	for (i = 0; i < 10; i++) {
137		u = R_CMCLK(sc, unit);
138		if (!(u&0x80))
139			break;
140		DELAY(1000);
141	}
142	if (u & 0x80) {
143		device_printf(sc->sc_dev,
144		    "Failed to stop clock for unit 0x%x", unit);
145		return (0);
146	}
147	if (hz == 0)
148		return (0);
149
150	u = 500000000/hz;
151	if (u < 4) {
152		device_printf(sc->sc_dev,
153		    "Frequency too high for unit 0x%x (max: 125 MHz)",
154		    unit);
155		return (0);
156	}
157	if (u > 0xfff) {
158		device_printf(sc->sc_dev,
159		    "Frequency too low for unit 0x%x (min: 123 kHz)",
160		    unit);
161		return (0);
162	}
163	hz = 500000000/u;
164	W_CMDIV(sc, unit, u << 12);
165
166	W_CMCLK(sc, unit, 0x16);
167	for (i = 0; i < 10; i++) {
168		u = R_CMCLK(sc, unit);
169		if ((u&0x80))
170			break;
171		DELAY(1000);
172	}
173	if (!(u & 0x80)) {
174		device_printf(sc->sc_dev,
175		    "Failed to start clock for unit 0x%x", unit);
176		return (0);
177	}
178	return (hz);
179}
180
181static int
182bcm2835_clkman_detach(device_t dev)
183{
184	struct bcm2835_clkman_softc *sc;
185
186	bus_generic_detach(dev);
187
188	sc = device_get_softc(dev);
189	if (sc->sc_m_res)
190		bus_release_resource(dev, SYS_RES_MEMORY, 0, sc->sc_m_res);
191
192	return (0);
193}
194
195static device_method_t bcm2835_clkman_methods[] = {
196	/* Device interface */
197	DEVMETHOD(device_probe,		bcm2835_clkman_probe),
198	DEVMETHOD(device_attach,	bcm2835_clkman_attach),
199	DEVMETHOD(device_detach,	bcm2835_clkman_detach),
200
201	DEVMETHOD_END
202};
203
204static devclass_t bcm2835_clkman_devclass;
205static driver_t bcm2835_clkman_driver = {
206	"bcm2835_clkman",
207	bcm2835_clkman_methods,
208	sizeof(struct bcm2835_clkman_softc),
209};
210
211DRIVER_MODULE(bcm2835_clkman, simplebus, bcm2835_clkman_driver,
212    bcm2835_clkman_devclass, 0, 0);
213MODULE_VERSION(bcm2835_clkman, 1);
214