xref: /freebsd/sys/dev/smbus/smbconf.c (revision 0fca6ea1d4eea4c934cfff25ac9ee8ad6fe95583)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 1998, 2001 Nicolas Souchu
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 
31 #include <sys/param.h>
32 #include <sys/systm.h>
33 #include <sys/lock.h>
34 #include <sys/module.h>
35 #include <sys/mutex.h>
36 #include <sys/bus.h>
37 
38 #include <dev/smbus/smbconf.h>
39 #include <dev/smbus/smbus.h>
40 #include "smbus_if.h"
41 
42 /*
43  * smbus_intr()
44  */
45 void
46 smbus_intr(device_t bus, u_char devaddr, char low, char high, int error)
47 {
48 	struct smbus_softc *sc = device_get_softc(bus);
49 
50 	/* call owner's intr routine */
51 	mtx_lock(&sc->lock);
52 	if (sc->owner)
53 		SMBUS_INTR(sc->owner, devaddr, low, high, error);
54 	mtx_unlock(&sc->lock);
55 }
56 
57 /*
58  * smbus_error()
59  *
60  * Converts an smbus error to a unix error.
61  */
62 int
63 smbus_error(int smb_error)
64 {
65 	int error = 0;
66 
67 	if (smb_error == SMB_ENOERR)
68 		return (0);
69 
70 	if (smb_error & (SMB_ENOTSUPP))
71 		error = ENODEV;
72 	else if (smb_error & (SMB_ENOACK))
73 		error = ENXIO;
74 	else if (smb_error & (SMB_ETIMEOUT))
75 		error = EWOULDBLOCK;
76 	else if (smb_error & (SMB_EBUSY))
77 		error = EBUSY;
78 	else if (smb_error & (SMB_EABORT | SMB_EBUSERR | SMB_ECOLLI))
79 		error = EIO;
80 	else
81 		error = EINVAL;
82 
83 	return (error);
84 }
85 
86 static int
87 smbus_poll(struct smbus_softc *sc, int how)
88 {
89 	int error;
90 
91 	switch (how) {
92 	case SMB_WAIT | SMB_INTR:
93 		error = msleep(sc, &sc->lock, SMBPRI|PCATCH, "smbreq", 0);
94 		break;
95 
96 	case SMB_WAIT | SMB_NOINTR:
97 		error = msleep(sc, &sc->lock, SMBPRI, "smbreq", 0);
98 		break;
99 
100 	default:
101 		error = EWOULDBLOCK;
102 		break;
103 	}
104 
105 	return (error);
106 }
107 
108 /*
109  * smbus_request_bus()
110  *
111  * Allocate the device to perform transfers.
112  *
113  * how	: SMB_WAIT or SMB_DONTWAIT
114  */
115 int
116 smbus_request_bus(device_t bus, device_t dev, int how)
117 {
118 	struct smbus_softc *sc = device_get_softc(bus);
119 	device_t parent;
120 	int error;
121 
122 	/* first, ask the underlying layers if the request is ok */
123 	parent = device_get_parent(bus);
124 	mtx_lock(&sc->lock);
125 	do {
126 		mtx_unlock(&sc->lock);
127 		error = SMBUS_CALLBACK(parent, SMB_REQUEST_BUS, &how);
128 		mtx_lock(&sc->lock);
129 
130 		if (error)
131 			error = smbus_poll(sc, how);
132 	} while (error == EWOULDBLOCK);
133 
134 	while (error == 0) {
135 		if (sc->owner && sc->owner != dev)
136 			error = smbus_poll(sc, how);
137 		else {
138 			sc->owner = dev;
139 			break;
140 		}
141 
142 		/* free any allocated resource */
143 		if (error) {
144 			mtx_unlock(&sc->lock);
145 			SMBUS_CALLBACK(parent, SMB_RELEASE_BUS, &how);
146 			return (error);
147 		}
148 	}
149 	mtx_unlock(&sc->lock);
150 
151 	return (error);
152 }
153 
154 /*
155  * smbus_release_bus()
156  *
157  * Release the device allocated with smbus_request_dev()
158  */
159 int
160 smbus_release_bus(device_t bus, device_t dev)
161 {
162 	struct smbus_softc *sc = device_get_softc(bus);
163 	int error;
164 
165 	/* first, ask the underlying layers if the release is ok */
166 	error = SMBUS_CALLBACK(device_get_parent(bus), SMB_RELEASE_BUS, NULL);
167 
168 	if (error)
169 		return (error);
170 
171 	mtx_lock(&sc->lock);
172 	if (sc->owner == dev) {
173 		sc->owner = NULL;
174 
175 		/* wakeup waiting processes */
176 		wakeup(sc);
177 	} else
178 		error = EACCES;
179 	mtx_unlock(&sc->lock);
180 
181 	return (error);
182 }
183