1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
|
/*
* Copyright (c) 2004, Technische Universitat Berlin
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* - Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* - Neither the name of the Technische Universitat Berlin nor the names
* of its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
* OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
* USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* Please refer to TEP 108 for more information about this component and its
* intended use.<br><br>
*
* This component provides the Resource, ArbiterInfo, and ResourceRequested
* interfaces and uses the ResourceConfigure interface as
* described in TEP 108. It provides arbitration to a shared resource.
* An queue is used to keep track of which users have put
* in requests for the resource. Upon the release of the resource by one
* of these users, the queue is checked and the next user
* that has a pending request will ge granted control of the resource. If
* there are no pending requests, then the resource becomes idle and any
* user can put in a request and immediately receive access to the
* Resource.
*
* @author Kevin Klues (klues@tkn.tu-berlin.de)
* @author Philip Levis
*/
generic module SimpleArbiterP() @safe() {
provides {
interface Resource[uint8_t id];
interface ResourceRequested[uint8_t id];
interface ArbiterInfo;
}
uses {
interface ResourceConfigure[uint8_t id];
interface ResourceQueue as Queue;
}
}
implementation {
enum {RES_IDLE = 0, RES_GRANTING = 1, RES_BUSY = 2};
enum {NO_RES = 0xFF};
uint8_t state = RES_IDLE;
norace uint8_t resId = NO_RES;
norace uint8_t reqResId;
task void grantedTask();
async command error_t Resource.request[uint8_t id]() {
signal ResourceRequested.requested[resId]();
atomic {
if(state == RES_IDLE) {
state = RES_GRANTING;
reqResId = id;
post grantedTask();
return SUCCESS;
}
return call Queue.enqueue(id);
}
}
async command error_t Resource.immediateRequest[uint8_t id]() {
signal ResourceRequested.immediateRequested[resId]();
atomic {
if(state == RES_IDLE) {
state = RES_BUSY;
resId = id;
call ResourceConfigure.configure[resId]();
return SUCCESS;
}
return FAIL;
}
}
async command error_t Resource.release[uint8_t id]() {
bool released = FALSE;
atomic {
if(state == RES_BUSY && resId == id) {
if(call Queue.isEmpty() == FALSE) {
resId = NO_RES;
reqResId = call Queue.dequeue();
state = RES_GRANTING;
post grantedTask();
}
else {
resId = NO_RES;
state = RES_IDLE;
}
released = TRUE;
}
}
if(released == TRUE) {
call ResourceConfigure.unconfigure[id]();
return SUCCESS;
}
return FAIL;
}
/**
Check if the Resource is currently in use
*/
async command bool ArbiterInfo.inUse() {
atomic {
if (state == RES_IDLE)
return FALSE;
}
return TRUE;
}
/**
Returns the current user of the Resource.
If there is no current user, the return value
will be 0xFF
*/
async command uint8_t ArbiterInfo.userId() {
atomic {
if(state != RES_BUSY)
return NO_RES;
return resId;
}
}
/**
* Returns whether you are the current owner of the resource or not
*/
async command bool Resource.isOwner[uint8_t id]() {
atomic {
if(resId == id && state == RES_BUSY) return TRUE;
else return FALSE;
}
}
task void grantedTask() {
atomic {
resId = reqResId;
state = RES_BUSY;
}
call ResourceConfigure.configure[resId]();
signal Resource.granted[resId]();
}
//Default event/command handlers
default event void Resource.granted[uint8_t id]() {
}
default async event void ResourceRequested.requested[uint8_t id]() {
}
default async event void ResourceRequested.immediateRequested[uint8_t id]() {
}
default async command void ResourceConfigure.configure[uint8_t id]() {
}
default async command void ResourceConfigure.unconfigure[uint8_t id]() {
}
}
|
