smbconf.c revision 93023 
1/*-
2 * Copyright (c) 1998, 2001 Nicolas Souchu
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 * $FreeBSD: head/sys/dev/smbus/smbconf.c 93023 2002-03-23 15:49:15Z nsouch $
27 *
28 */
29#include <sys/param.h>
30#include <sys/systm.h>
31#include <sys/module.h>
32#include <sys/bus.h>
33
34#include <dev/smbus/smbconf.h>
35#include <dev/smbus/smbus.h>
36#include "smbus_if.h"
37
38/*
39 * smbus_intr()
40 */
41void
42smbus_intr(device_t bus, u_char devaddr, char low, char high, int error)
43{
44	struct smbus_softc *sc = (struct smbus_softc *)device_get_softc(bus);
45
46	/* call owner's intr routine */
47	if (sc->owner)
48		SMBUS_INTR(sc->owner, devaddr, low, high, error);
49
50	return;
51}
52
53/*
54 * smbus_error()
55 *
56 * Converts an smbus error to a unix error.
57 */
58int
59smbus_error(int smb_error)
60{
61	int error = 0;
62
63	if (smb_error == SMB_ENOERR)
64		return (0);
65
66	if (smb_error & (SMB_ENOTSUPP)) {
67		error = ENODEV;
68	} else if (smb_error & (SMB_ENOACK)) {
69		error = ENXIO;
70	} else if (smb_error & (SMB_ETIMEOUT)) {
71		error = EWOULDBLOCK;
72	} else if (smb_error & (SMB_EBUSY)) {
73		error = EBUSY;
74	} else {
75		error = EINVAL;
76	}
77
78	return (error);
79}
80
81static int
82smbus_poll(struct smbus_softc *sc, int how)
83{
84	int error;
85
86	switch (how) {
87	case (SMB_WAIT | SMB_INTR):
88		error = tsleep(sc, SMBPRI|PCATCH, "smbreq", 0);
89		break;
90
91	case (SMB_WAIT | SMB_NOINTR):
92		error = tsleep(sc, SMBPRI, "smbreq", 0);
93		break;
94
95	default:
96		return (EWOULDBLOCK);
97		break;
98	}
99
100	return (error);
101}
102
103/*
104 * smbus_request_bus()
105 *
106 * Allocate the device to perform transfers.
107 *
108 * how	: SMB_WAIT or SMB_DONTWAIT
109 */
110int
111smbus_request_bus(device_t bus, device_t dev, int how)
112{
113	struct smbus_softc *sc = (struct smbus_softc *)device_get_softc(bus);
114	int s, error = 0;
115
116	/* first, ask the underlying layers if the request is ok */
117	do {
118		error = SMBUS_CALLBACK(device_get_parent(bus),
119						SMB_REQUEST_BUS, (caddr_t)&how);
120		if (error)
121			error = smbus_poll(sc, how);
122	} while (error == EWOULDBLOCK);
123
124	while (!error) {
125		s = splhigh();
126		if (sc->owner && sc->owner != dev) {
127			splx(s);
128
129			error = smbus_poll(sc, how);
130		} else {
131			sc->owner = dev;
132
133			splx(s);
134			return (0);
135		}
136
137		/* free any allocated resource */
138		if (error)
139			SMBUS_CALLBACK(device_get_parent(bus), SMB_RELEASE_BUS,
140					(caddr_t)&how);
141	}
142
143	return (error);
144}
145
146/*
147 * smbus_release_bus()
148 *
149 * Release the device allocated with smbus_request_dev()
150 */
151int
152smbus_release_bus(device_t bus, device_t dev)
153{
154	struct smbus_softc *sc = (struct smbus_softc *)device_get_softc(bus);
155	int s, error;
156
157	/* first, ask the underlying layers if the release is ok */
158	error = SMBUS_CALLBACK(device_get_parent(bus), SMB_RELEASE_BUS, NULL);
159
160	if (error)
161		return (error);
162
163	s = splhigh();
164	if (sc->owner != dev) {
165		splx(s);
166		return (EACCES);
167	}
168
169	sc->owner = 0;
170	splx(s);
171
172	/* wakeup waiting processes */
173	wakeup(sc);
174
175	return (0);
176}
177