1 | /* |
2 | * Copyright (c) 1998-2010 Apple 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 | #if !defined(__LP64__) |
30 | |
31 | #include <IOKit/IOCommandQueue.h> |
32 | #include <IOKit/IOWorkLoop.h> |
33 | #include <IOKit/IOTimeStamp.h> |
34 | #include <IOKit/IOKitDebug.h> |
35 | |
36 | #include <mach/sync_policy.h> |
37 | |
38 | #if IOKITSTATS |
39 | |
40 | #define IOStatisticsInitializeCounter() \ |
41 | IOStatistics::setCounterType(reserved->counter, kIOStatisticsCommandQueueCounter) |
42 | |
43 | #define IOStatisticsActionCall() \ |
44 | IOStatistics::countCommandQueueActionCall(reserved->counter) |
45 | |
46 | #else |
47 | |
48 | #define IOStatisticsInitializeCounter() |
49 | #define IOStatisticsActionCall() |
50 | |
51 | #endif /* IOKITSTATS */ |
52 | |
53 | #define NUM_FIELDS_IN_COMMAND 4 |
54 | typedef struct commandEntryTag { |
55 | void *f[NUM_FIELDS_IN_COMMAND]; |
56 | } commandEntryT; |
57 | |
58 | #define super IOEventSource |
59 | |
60 | OSDefineMetaClassAndStructors(IOCommandQueue, IOEventSource) |
61 | |
62 | /*[ |
63 | Instance Methods |
64 | |
65 | initWithNext:owner:action:size: |
66 | - initWithNext: (IOEventSource *) inNext |
67 | owner: (id) inOwner |
68 | action: (SEL) inAction |
69 | size: (int) inSize; |
70 | |
71 | Primary initialiser for the IOCommandQueue class. Returns an |
72 | IOCommandQueue object that is initialised with the next object in |
73 | the chain and the owner and action. On return the signalWorkAvailableIMP |
74 | has been cached for this function. |
75 | |
76 | If the object fails to initialise for some reason then [self free] will |
77 | be called and nil will be returned. |
78 | |
79 | See also: initWithNext:owner:action:(IOEventSource) |
80 | ]*/ |
81 | bool IOCommandQueue::init(OSObject *inOwner, |
82 | IOCommandQueueAction inAction, |
83 | int inSize) |
84 | { |
85 | if ( !super::init(inOwner, (IOEventSourceAction) inAction) ) |
86 | return false; |
87 | |
88 | if (KERN_SUCCESS |
89 | != semaphore_create(kernel_task, &producerSema, SYNC_POLICY_FIFO, inSize)) |
90 | return false; |
91 | |
92 | size = inSize + 1; /* Allocate one more entry than needed */ |
93 | |
94 | queue = (void *)kalloc(size * sizeof(commandEntryT)); |
95 | if (!queue) |
96 | return false; |
97 | |
98 | producerLock = IOLockAlloc(); |
99 | if (!producerLock) |
100 | return false; |
101 | |
102 | producerIndex = consumerIndex = 0; |
103 | |
104 | IOStatisticsInitializeCounter(); |
105 | |
106 | return true; |
107 | } |
108 | |
109 | IOCommandQueue * |
110 | IOCommandQueue::commandQueue(OSObject *inOwner, |
111 | IOCommandQueueAction inAction, |
112 | int inSize) |
113 | { |
114 | IOCommandQueue *me = new IOCommandQueue; |
115 | |
116 | if (me && !me->init(inOwner, inAction, inSize)) { |
117 | me->free(); |
118 | return 0; |
119 | } |
120 | |
121 | return me; |
122 | } |
123 | |
124 | /*[ |
125 | free |
126 | - free |
127 | |
128 | Mandatory free of the object independent of the current retain count. |
129 | Returns nil. |
130 | ]*/ |
131 | void IOCommandQueue::free() |
132 | { |
133 | if (queue) |
134 | kfree(queue, size * sizeof(commandEntryT)); |
135 | if (producerSema) |
136 | semaphore_destroy(kernel_task, producerSema); |
137 | if (producerLock) |
138 | IOLockFree(producerLock); |
139 | |
140 | super::free(); |
141 | } |
142 | |
143 | #if NUM_FIELDS_IN_COMMAND != 4 |
144 | #error IOCommandQueue::checkForWork needs to be updated for new command size |
145 | #endif |
146 | |
147 | bool IOCommandQueue::checkForWork() |
148 | { |
149 | void *field0, *field1, *field2, *field3; |
150 | bool trace = ( gIOKitTrace & kIOTraceCommandGates ) ? true : false; |
151 | |
152 | if (!enabled || consumerIndex == producerIndex) |
153 | return false; |
154 | |
155 | { |
156 | commandEntryT *q = (commandEntryT *) queue; |
157 | int localIndex = consumerIndex; |
158 | |
159 | field0 = q[localIndex].f[0]; field1 = q[localIndex].f[1]; |
160 | field2 = q[localIndex].f[2]; field3 = q[localIndex].f[3]; |
161 | semaphore_signal(producerSema); |
162 | } |
163 | |
164 | if (++consumerIndex >= size) |
165 | consumerIndex = 0; |
166 | |
167 | if (trace) |
168 | IOTimeStampStartConstant(IODBG_CMDQ(IOCMDQ_ACTION), |
169 | VM_KERNEL_ADDRHIDE(action), VM_KERNEL_ADDRHIDE(owner)); |
170 | |
171 | IOStatisticsActionCall(); |
172 | (*(IOCommandQueueAction) action)(owner, field0, field1, field2, field3); |
173 | |
174 | if (trace) |
175 | IOTimeStampEndConstant(IODBG_CMDQ(IOCMDQ_ACTION), |
176 | VM_KERNEL_ADDRHIDE(action), VM_KERNEL_ADDRHIDE(owner)); |
177 | |
178 | return (consumerIndex != producerIndex); |
179 | } |
180 | |
181 | /*[ |
182 | enqueueSleep:command: |
183 | - (kern_return_t) enqueueSleepRaw: (BOOL) gotoSleep |
184 | field0: (void *) field0 field1: (void *) field1 |
185 | field2: (void *) field2 field3: (void *) field3; |
186 | |
187 | Key method that enqueues the four input fields onto the command queue |
188 | and calls signalWorkAvailable to indicate that work is available to the |
189 | consumer. This routine is safe against multiple threaded producers. |
190 | |
191 | A family of convenience functions have been provided to assist with the |
192 | enqueueing of an method selector and an integer tag. This relies on the |
193 | IODevice rawCommandOccurred... command to forward on the requests. |
194 | |
195 | See also: signalWorkAvailable, checkForWork |
196 | ]*/ |
197 | #if NUM_FIELDS_IN_COMMAND != 4 |
198 | #error IOCommandQueue::enqueueCommand needs to be updated |
199 | #endif |
200 | |
201 | kern_return_t |
202 | IOCommandQueue::enqueueCommand(bool gotoSleep, |
203 | void *field0, void *field1, |
204 | void *field2, void *field3) |
205 | { |
206 | kern_return_t rtn = KERN_SUCCESS; |
207 | int retry; |
208 | |
209 | /* Make sure there is room in the queue before doing anything else */ |
210 | |
211 | if (gotoSleep) { |
212 | retry = 0; |
213 | do |
214 | rtn = semaphore_wait(producerSema); |
215 | while( (KERN_SUCCESS != rtn) |
216 | && (KERN_OPERATION_TIMED_OUT != rtn) |
217 | && (KERN_SEMAPHORE_DESTROYED != rtn) |
218 | && (KERN_TERMINATED != rtn) |
219 | && ((retry++) < 4)); |
220 | } else |
221 | rtn = semaphore_timedwait(producerSema, MACH_TIMESPEC_ZERO); |
222 | |
223 | if (KERN_SUCCESS != rtn) |
224 | return rtn; |
225 | |
226 | /* Block other producers */ |
227 | IOTakeLock(producerLock); |
228 | |
229 | /* |
230 | * Make sure that we update the current producer entry before we |
231 | * increment the producer pointer. This avoids a nasty race as the |
232 | * test for work is producerIndex != consumerIndex and a signal. |
233 | */ |
234 | { |
235 | commandEntryT *q = (commandEntryT *) queue; |
236 | int localIndex = producerIndex; |
237 | |
238 | q[localIndex].f[0] = field0; q[localIndex].f[1] = field1; |
239 | q[localIndex].f[2] = field2; q[localIndex].f[3] = field3; |
240 | } |
241 | if (++producerIndex >= size) |
242 | producerIndex = 0; |
243 | |
244 | /* Clear to allow other producers to go now */ |
245 | IOUnlock(producerLock); |
246 | |
247 | /* |
248 | * Right we have created some new work, we had better make sure that |
249 | * we notify the work loop that it has to test producerIndex. |
250 | */ |
251 | signalWorkAvailable(); |
252 | return rtn; |
253 | } |
254 | |
255 | int IOCommandQueue::performAndFlush(OSObject *target, |
256 | IOCommandQueueAction inAction) |
257 | { |
258 | int numEntries; |
259 | kern_return_t rtn; |
260 | |
261 | // Set the defaults if necessary |
262 | if (!target) |
263 | target = owner; |
264 | if (!inAction) |
265 | inAction = (IOCommandQueueAction) action; |
266 | |
267 | // Lock out the producers first |
268 | do { |
269 | rtn = semaphore_timedwait(producerSema, MACH_TIMESPEC_ZERO); |
270 | } while (rtn == KERN_SUCCESS); |
271 | |
272 | // now step over all remaining entries in the command queue |
273 | for (numEntries = 0; consumerIndex != producerIndex; ) { |
274 | void *field0, *field1, *field2, *field3; |
275 | |
276 | { |
277 | commandEntryT *q = (commandEntryT *) queue; |
278 | int localIndex = consumerIndex; |
279 | |
280 | field0 = q[localIndex].f[0]; field1 = q[localIndex].f[1]; |
281 | field2 = q[localIndex].f[2]; field3 = q[localIndex].f[3]; |
282 | } |
283 | |
284 | if (++consumerIndex >= size) |
285 | consumerIndex = 0; |
286 | |
287 | (*inAction)(target, field0, field1, field2, field3); |
288 | } |
289 | |
290 | // finally refill the producer semaphore to size - 1 |
291 | for (int i = 1; i < size; i++) |
292 | semaphore_signal(producerSema); |
293 | |
294 | return numEntries; |
295 | } |
296 | |
297 | #endif /* !defined(__LP64__) */ |
298 | |