1/*
2 * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
3 *
4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. The rights granted to you under the License
10 * may not be used to create, or enable the creation or redistribution of,
11 * unlawful or unlicensed copies of an Apple operating system, or to
12 * circumvent, violate, or enable the circumvention or violation of, any
13 * terms of an Apple operating system software license agreement.
14 *
15 * Please obtain a copy of the License at
16 * http://www.opensource.apple.com/apsl/ and read it before using this file.
17 *
18 * The Original Code and all software distributed under the License are
19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23 * Please see the License for the specific language governing rights and
24 * limitations under the License.
25 *
26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27 */
28
29#include <IOKit/IODataQueue.h>
30#include <IOKit/IODataQueueShared.h>
31#include <IOKit/IOLib.h>
32#include <IOKit/IOMemoryDescriptor.h>
33
34#ifdef enqueue
35#undef enqueue
36#endif
37
38#ifdef dequeue
39#undef dequeue
40#endif
41
42#define super OSObject
43
44OSDefineMetaClassAndStructors(IODataQueue, OSObject)
45
46IODataQueue *IODataQueue::withCapacity(UInt32 size)
47{
48    IODataQueue *dataQueue = new IODataQueue;
49
50    if (dataQueue) {
51        if  (!dataQueue->initWithCapacity(size)) {
52            dataQueue->release();
53            dataQueue = 0;
54        }
55    }
56
57    return dataQueue;
58}
59
60IODataQueue *IODataQueue::withEntries(UInt32 numEntries, UInt32 entrySize)
61{
62    IODataQueue *dataQueue = new IODataQueue;
63
64    if (dataQueue) {
65        if (!dataQueue->initWithEntries(numEntries, entrySize)) {
66            dataQueue->release();
67            dataQueue = 0;
68        }
69    }
70
71    return dataQueue;
72}
73
74Boolean IODataQueue::initWithCapacity(UInt32 size)
75{
76    vm_size_t allocSize = 0;
77
78    if (!super::init()) {
79        return false;
80    }
81
82    allocSize = round_page(size + DATA_QUEUE_MEMORY_HEADER_SIZE);
83
84    if (allocSize < size) {
85        return false;
86    }
87
88    dataQueue = (IODataQueueMemory *)IOMallocAligned(allocSize, PAGE_SIZE);
89    if (dataQueue == 0) {
90        return false;
91    }
92
93    dataQueue->queueSize    = size;
94    dataQueue->head         = 0;
95    dataQueue->tail         = 0;
96
97    return true;
98}
99
100Boolean IODataQueue::initWithEntries(UInt32 numEntries, UInt32 entrySize)
101{
102    return (initWithCapacity((numEntries + 1) * (DATA_QUEUE_ENTRY_HEADER_SIZE + entrySize)));
103}
104
105void IODataQueue::free()
106{
107    if (dataQueue) {
108        IOFreeAligned(dataQueue, round_page(dataQueue->queueSize + DATA_QUEUE_MEMORY_HEADER_SIZE));
109    }
110
111    super::free();
112
113    return;
114}
115
116Boolean IODataQueue::enqueue(void * data, UInt32 dataSize)
117{
118    const UInt32       head      = dataQueue->head;  // volatile
119    const UInt32       tail      = dataQueue->tail;
120    const UInt32       entrySize = dataSize + DATA_QUEUE_ENTRY_HEADER_SIZE;
121    IODataQueueEntry * entry;
122
123    if ( tail >= head )
124    {
125        // Is there enough room at the end for the entry?
126        if ( (tail + entrySize) <= dataQueue->queueSize )
127        {
128            entry = (IODataQueueEntry *)((UInt8 *)dataQueue->queue + tail);
129
130            entry->size = dataSize;
131            memcpy(&entry->data, data, dataSize);
132
133            // The tail can be out of bound when the size of the new entry
134            // exactly matches the available space at the end of the queue.
135            // The tail can range from 0 to dataQueue->queueSize inclusive.
136
137            dataQueue->tail += entrySize;
138        }
139        else if ( head > entrySize ) 	// Is there enough room at the beginning?
140        {
141            // Wrap around to the beginning, but do not allow the tail to catch
142            // up to the head.
143
144            dataQueue->queue->size = dataSize;
145
146            // We need to make sure that there is enough room to set the size before
147            // doing this. The user client checks for this and will look for the size
148            // at the beginning if there isn't room for it at the end.
149
150            if ( ( dataQueue->queueSize - tail ) >= DATA_QUEUE_ENTRY_HEADER_SIZE )
151            {
152                ((IODataQueueEntry *)((UInt8 *)dataQueue->queue + tail))->size = dataSize;
153            }
154
155            memcpy(&dataQueue->queue->data, data, dataSize);
156            dataQueue->tail = entrySize;
157        }
158        else
159        {
160            return false;	// queue is full
161        }
162    }
163    else
164    {
165        // Do not allow the tail to catch up to the head when the queue is full.
166        // That's why the comparison uses a '>' rather than '>='.
167
168        if ( (head - tail) > entrySize )
169        {
170            entry = (IODataQueueEntry *)((UInt8 *)dataQueue->queue + tail);
171
172            entry->size = dataSize;
173            memcpy(&entry->data, data, dataSize);
174            dataQueue->tail += entrySize;
175        }
176        else
177        {
178            return false;	// queue is full
179        }
180    }
181
182    // Send notification (via mach message) that data is available.
183
184    if ( ( head == tail )                /* queue was empty prior to enqueue() */
185    ||   ( dataQueue->head == tail ) )   /* queue was emptied during enqueue() */
186    {
187        sendDataAvailableNotification();
188    }
189
190    return true;
191}
192
193void IODataQueue::setNotificationPort(mach_port_t port)
194{
195    static struct _notifyMsg init_msg = { {
196        MACH_MSGH_BITS(MACH_MSG_TYPE_COPY_SEND, 0),
197        sizeof (struct _notifyMsg),
198        MACH_PORT_NULL,
199        MACH_PORT_NULL,
200        0,
201        0
202    } };
203
204    if (notifyMsg == 0) {
205        notifyMsg = IOMalloc(sizeof(struct _notifyMsg));
206    }
207
208    *((struct _notifyMsg *)notifyMsg) = init_msg;
209
210    ((struct _notifyMsg *)notifyMsg)->h.msgh_remote_port = port;
211}
212
213void IODataQueue::sendDataAvailableNotification()
214{
215    kern_return_t		kr;
216    mach_msg_header_t *	msgh;
217
218    msgh = (mach_msg_header_t *)notifyMsg;
219    if (msgh && msgh->msgh_remote_port) {
220        kr = mach_msg_send_from_kernel_proper(msgh, msgh->msgh_size);
221        switch(kr) {
222            case MACH_SEND_TIMED_OUT:	// Notification already sent
223            case MACH_MSG_SUCCESS:
224                break;
225            default:
226                IOLog("%s: dataAvailableNotification failed - msg_send returned: %d\n", /*getName()*/"IODataQueue", kr);
227                break;
228        }
229    }
230}
231
232IOMemoryDescriptor *IODataQueue::getMemoryDescriptor()
233{
234    IOMemoryDescriptor *descriptor = 0;
235
236    if (dataQueue != 0) {
237        descriptor = IOMemoryDescriptor::withAddress(dataQueue, dataQueue->queueSize + DATA_QUEUE_MEMORY_HEADER_SIZE, kIODirectionOutIn);
238    }
239
240    return descriptor;
241}
242
243