xref: /freebsd-13.1/sys/dev/extres/syscon/syscon.c (revision 290ce7d2)
1 /*-
2  * Copyright (c) 2017 Kyle Evans <[email protected]>
3  * 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 THE 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 THE 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 /*
28  * This is a generic syscon driver, whose purpose is to provide access to
29  * various unrelated bits packed in a single register space. It is usually used
30  * as a fallback to more specific driver, but works well enough for simple
31  * access.
32  */
33 
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD$");
36 #include "opt_platform.h"
37 
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/bus.h>
41 #include <sys/kernel.h>
42 #include <sys/kobj.h>
43 #include <sys/lock.h>
44 #include <sys/module.h>
45 #include <sys/rman.h>
46 #include <sys/sx.h>
47 #include <sys/queue.h>
48 
49 #include <machine/bus.h>
50 
51 #ifdef FDT
52 #include <dev/ofw/ofw_bus.h>
53 #include <dev/ofw/ofw_bus_subr.h>
54 #endif
55 
56 #include "syscon_if.h"
57 #include "syscon.h"
58 
59 /*
60  * Syscon interface details
61  */
62 typedef TAILQ_HEAD(syscon_list, syscon) syscon_list_t;
63 
64 /*
65  * Declarations
66  */
67 static int syscon_method_init(struct syscon *syscon);
68 static int syscon_method_uninit(struct syscon *syscon);
69 
70 MALLOC_DEFINE(M_SYSCON, "syscon", "Syscon driver");
71 
72 static syscon_list_t syscon_list = TAILQ_HEAD_INITIALIZER(syscon_list);
73 static struct sx		syscon_topo_lock;
74 SX_SYSINIT(syscon_topology, &syscon_topo_lock, "Syscon topology lock");
75 
76 /*
77  * Syscon methods.
78  */
79 static syscon_method_t syscon_methods[] = {
80 	SYSCONMETHOD(syscon_init,	syscon_method_init),
81 	SYSCONMETHOD(syscon_uninit,	syscon_method_uninit),
82 
83 	SYSCONMETHOD_END
84 };
85 DEFINE_CLASS_0(syscon, syscon_class, syscon_methods, 0);
86 
87 #define SYSCON_TOPO_SLOCK()	sx_slock(&syscon_topo_lock)
88 #define SYSCON_TOPO_XLOCK()	sx_xlock(&syscon_topo_lock)
89 #define SYSCON_TOPO_UNLOCK()	sx_unlock(&syscon_topo_lock)
90 #define SYSCON_TOPO_ASSERT()	sx_assert(&syscon_topo_lock, SA_LOCKED)
91 #define SYSCON_TOPO_XASSERT()	sx_assert(&syscon_topo_lock, SA_XLOCKED)
92 
93 /*
94  * Default syscon methods for base class.
95  */
96 static int
97 syscon_method_init(struct syscon *syscon)
98 {
99 
100 	return (0);
101 };
102 
103 static int
104 syscon_method_uninit(struct syscon *syscon)
105 {
106 
107 	return (0);
108 };
109 
110 void *
111 syscon_get_softc(struct syscon *syscon)
112 {
113 
114 	return (syscon->softc);
115 };
116 
117 /*
118  * Create and initialize syscon object, but do not register it.
119  */
120 struct syscon *
121 syscon_create(device_t pdev, syscon_class_t syscon_class)
122 {
123 	struct syscon *syscon;
124 
125 	/* Create object and initialize it. */
126 	syscon = malloc(sizeof(struct syscon), M_SYSCON,
127 	    M_WAITOK | M_ZERO);
128 	kobj_init((kobj_t)syscon, (kobj_class_t)syscon_class);
129 
130 	/* Allocate softc if required. */
131 	if (syscon_class->size > 0)
132 		syscon->softc = malloc(syscon_class->size, M_SYSCON,
133 		    M_WAITOK | M_ZERO);
134 
135 	/* Rest of init. */
136 	syscon->pdev = pdev;
137 	return (syscon);
138 }
139 
140 /* Register syscon object. */
141 struct syscon *
142 syscon_register(struct syscon *syscon)
143 {
144 	int rv;
145 
146 #ifdef FDT
147 	if (syscon->ofw_node <= 0)
148 		syscon->ofw_node = ofw_bus_get_node(syscon->pdev);
149 	if (syscon->ofw_node <= 0)
150 		return (NULL);
151 #endif
152 
153 	rv = SYSCON_INIT(syscon);
154 	if (rv != 0) {
155 		printf("SYSCON_INIT failed: %d\n", rv);
156 		return (NULL);
157 	}
158 
159 #ifdef FDT
160 	OF_device_register_xref(OF_xref_from_node(syscon->ofw_node),
161 	    syscon->pdev);
162 #endif
163 	SYSCON_TOPO_XLOCK();
164 	TAILQ_INSERT_TAIL(&syscon_list, syscon, syscon_link);
165 	SYSCON_TOPO_UNLOCK();
166 	return (syscon);
167 }
168 
169 int
170 syscon_unregister(struct syscon *syscon)
171 {
172 
173 	SYSCON_TOPO_XLOCK();
174 	TAILQ_REMOVE(&syscon_list, syscon, syscon_link);
175 	SYSCON_TOPO_UNLOCK();
176 #ifdef FDT
177 	OF_device_register_xref(OF_xref_from_node(syscon->ofw_node), NULL);
178 #endif
179 	return (SYSCON_UNINIT(syscon));
180 }
181 
182 /**
183  * Provider methods
184  */
185 #ifdef FDT
186 static struct syscon *
187 syscon_find_by_ofw_node(phandle_t node)
188 {
189 	struct syscon *entry;
190 
191 	SYSCON_TOPO_ASSERT();
192 
193 	TAILQ_FOREACH(entry, &syscon_list, syscon_link) {
194 		if (entry->ofw_node == node)
195 			return (entry);
196 	}
197 
198 	return (NULL);
199 }
200 
201 struct syscon *
202 syscon_create_ofw_node(device_t pdev, syscon_class_t syscon_class,
203     phandle_t node)
204 {
205 	struct syscon *syscon;
206 
207 	syscon = syscon_create(pdev, syscon_class);
208 	if (syscon == NULL)
209 		return (NULL);
210 	syscon->ofw_node = node;
211 	if (syscon_register(syscon) == NULL)
212 		return (NULL);
213 	return (syscon);
214 }
215 
216 phandle_t
217 syscon_get_ofw_node(struct syscon *syscon)
218 {
219 
220 	return (syscon->ofw_node);
221 }
222 
223 int
224 syscon_get_by_ofw_property(device_t cdev, phandle_t cnode, char *name,
225     struct syscon **syscon)
226 {
227 	pcell_t *cells;
228 	int ncells;
229 
230 	if (cnode <= 0)
231 		cnode = ofw_bus_get_node(cdev);
232 	if (cnode <= 0) {
233 		device_printf(cdev,
234 		    "%s called on not ofw based device\n", __func__);
235 		return (ENXIO);
236 	}
237 	ncells = OF_getencprop_alloc(cnode, name, sizeof(pcell_t),
238 	    (void **)&cells);
239 	if (ncells < 1)
240 		return (ENXIO);
241 
242 	/* Translate to syscon node. */
243 	SYSCON_TOPO_SLOCK();
244 	*syscon = syscon_find_by_ofw_node(OF_node_from_xref(cells[0]));
245 	if (*syscon == NULL) {
246 		SYSCON_TOPO_UNLOCK();
247 		device_printf(cdev, "Failed to find syscon node\n");
248 		OF_prop_free(cells);
249 		return (ENODEV);
250 	}
251 	SYSCON_TOPO_UNLOCK();
252 	OF_prop_free(cells);
253 	return (0);
254 }
255 #endif
256