1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2015 Michal Meloun
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29/*
30 * This is a generic syscon driver, whose purpose is to provide access to
31 * various unrelated bits packed in a single register space. It is usually used
32 * as a fallback to more specific driver, but works well enough for simple
33 * access.
34 */
35
36#include <sys/cdefs.h>
37__FBSDID("$FreeBSD$");
38#include <sys/param.h>
39#include <sys/systm.h>
40#include <sys/bus.h>
41#include <sys/kernel.h>
42#include <sys/lock.h>
43#include <sys/module.h>
44#include <sys/rman.h>
45
46#include <machine/bus.h>
47
48#include <dev/ofw/ofw_bus.h>
49#include <dev/ofw/ofw_bus_subr.h>
50
51#include "syscon_if.h"
52#include "syscon.h"
53#include "syscon_generic.h"
54
55MALLOC_DECLARE(M_SYSCON);
56
57static uint32_t syscon_generic_unlocked_read_4(struct syscon *syscon,
58    bus_size_t offset);
59static int syscon_generic_unlocked_write_4(struct syscon *syscon,
60    bus_size_t offset, uint32_t val);
61static int syscon_generic_unlocked_modify_4(struct syscon *syscon,
62    bus_size_t offset, uint32_t clear_bits, uint32_t set_bits);
63static int syscon_generic_detach(device_t dev);
64/*
65 * Generic syscon driver (FDT)
66 */
67static struct ofw_compat_data compat_data[] = {
68	{"syscon",	1},
69	{NULL,		0}
70};
71
72#define SYSCON_LOCK(_sc)		mtx_lock_spin(&(_sc)->mtx)
73#define	SYSCON_UNLOCK(_sc)		mtx_unlock_spin(&(_sc)->mtx)
74#define SYSCON_LOCK_INIT(_sc)		mtx_init(&(_sc)->mtx,		\
75	    device_get_nameunit((_sc)->dev), "syscon", MTX_SPIN)
76#define SYSCON_LOCK_DESTROY(_sc)	mtx_destroy(&(_sc)->mtx);
77#define SYSCON_ASSERT_LOCKED(_sc)	mtx_assert(&(_sc)->mtx, MA_OWNED);
78#define SYSCON_ASSERT_UNLOCKED(_sc)	mtx_assert(&(_sc)->mtx, MA_NOTOWNED);
79
80static syscon_method_t syscon_generic_methods[] = {
81	SYSCONMETHOD(syscon_unlocked_read_4,  syscon_generic_unlocked_read_4),
82	SYSCONMETHOD(syscon_unlocked_write_4, syscon_generic_unlocked_write_4),
83	SYSCONMETHOD(syscon_unlocked_modify_4, syscon_generic_unlocked_modify_4),
84
85	SYSCONMETHOD_END
86};
87DEFINE_CLASS_1(syscon_generic, syscon_generic_class, syscon_generic_methods,
88    0, syscon_class);
89
90static uint32_t
91syscon_generic_unlocked_read_4(struct syscon *syscon, bus_size_t offset)
92{
93	struct syscon_generic_softc *sc;
94	uint32_t val;
95
96	sc = device_get_softc(syscon->pdev);
97	SYSCON_ASSERT_LOCKED(sc);
98	val = bus_read_4(sc->mem_res, offset);
99	return (val);
100}
101
102static int
103syscon_generic_unlocked_write_4(struct syscon *syscon, bus_size_t offset, uint32_t val)
104{
105	struct syscon_generic_softc *sc;
106
107	sc = device_get_softc(syscon->pdev);
108	SYSCON_ASSERT_LOCKED(sc);
109	bus_write_4(sc->mem_res, offset, val);
110	return (0);
111}
112
113static int
114syscon_generic_unlocked_modify_4(struct syscon *syscon, bus_size_t offset,
115    uint32_t clear_bits, uint32_t set_bits)
116{
117	struct syscon_generic_softc *sc;
118	uint32_t val;
119
120	sc = device_get_softc(syscon->pdev);
121	SYSCON_ASSERT_LOCKED(sc);
122	val = bus_read_4(sc->mem_res, offset);
123	val &= ~clear_bits;
124	val |= set_bits;
125	bus_write_4(sc->mem_res, offset, val);
126	return (0);
127}
128
129static void
130syscon_generic_lock(device_t dev)
131{
132	struct syscon_generic_softc *sc;
133
134	sc = device_get_softc(dev);
135	SYSCON_LOCK(sc);
136}
137
138static void
139syscon_generic_unlock(device_t dev)
140{
141	struct syscon_generic_softc *sc;
142
143	sc = device_get_softc(dev);
144	SYSCON_UNLOCK(sc);
145}
146
147static int
148syscon_generic_probe(device_t dev)
149{
150
151	if (!ofw_bus_status_okay(dev))
152		return (ENXIO);
153	if (ofw_bus_search_compatible(dev, compat_data)->ocd_data == 0)
154		return (ENXIO);
155
156	device_set_desc(dev, "syscon");
157	return (BUS_PROBE_GENERIC);
158}
159
160static int
161syscon_generic_attach(device_t dev)
162{
163	struct syscon_generic_softc *sc;
164	int rid, rv;
165
166	sc = device_get_softc(dev);
167	sc->dev = dev;
168	rid = 0;
169
170	sc->mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid,
171	    RF_ACTIVE);
172	if (sc->mem_res == NULL) {
173		device_printf(dev, "Cannot allocate memory resource\n");
174		return (ENXIO);
175	}
176
177	SYSCON_LOCK_INIT(sc);
178	sc->syscon = syscon_create_ofw_node(dev, &syscon_generic_class,
179		ofw_bus_get_node(dev));
180	if (sc->syscon == NULL) {
181		device_printf(dev, "Failed to create/register syscon\n");
182		syscon_generic_detach(dev);
183		return (ENXIO);
184	}
185	if (ofw_bus_is_compatible(dev, "simple-bus")) {
186		rv = simplebus_attach_impl(sc->dev);
187		if (rv != 0) {
188			device_printf(dev, "Failed to create simplebus\n");
189			syscon_generic_detach(dev);
190			return (ENXIO);
191		}
192		sc->simplebus_attached = true;
193	}
194
195	return (bus_generic_attach(dev));
196}
197
198static int
199syscon_generic_detach(device_t dev)
200{
201	struct syscon_generic_softc *sc;
202
203	sc = device_get_softc(dev);
204	if (sc->syscon != NULL) {
205		syscon_unregister(sc->syscon);
206		free(sc->syscon, M_SYSCON);
207	}
208	if (sc->simplebus_attached)
209		simplebus_detach(dev);
210	SYSCON_LOCK_DESTROY(sc);
211
212	if (sc->mem_res != NULL)
213		bus_release_resource(dev, SYS_RES_MEMORY, 0, sc->mem_res);
214	return (0);
215}
216
217static device_method_t syscon_generic_dmethods[] = {
218	/* Device interface */
219	DEVMETHOD(device_probe,		syscon_generic_probe),
220	DEVMETHOD(device_attach,	syscon_generic_attach),
221	DEVMETHOD(device_detach,	syscon_generic_detach),
222
223	DEVMETHOD(syscon_device_lock,	syscon_generic_lock),
224	DEVMETHOD(syscon_device_unlock,	syscon_generic_unlock),
225
226	DEVMETHOD_END
227};
228
229DEFINE_CLASS_1(syscon_generic_dev, syscon_generic_driver, syscon_generic_dmethods,
230    sizeof(struct syscon_generic_softc), simplebus_driver);
231static devclass_t syscon_generic_devclass;
232
233EARLY_DRIVER_MODULE(syscon_generic, simplebus, syscon_generic_driver,
234    syscon_generic_devclass, 0, 0, BUS_PASS_DEFAULT);
235MODULE_VERSION(syscon_generic, 1);
236