1 /******************************************************************************
2 *
3 * Module Name: evglock - Global Lock support
4 *
5 *****************************************************************************/
6
7 /*
8 * Copyright (C) 2000 - 2013, Intel Corp.
9 * All rights reserved.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions, and the following disclaimer,
16 * without modification.
17 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
18 * substantially similar to the "NO WARRANTY" disclaimer below
19 * ("Disclaimer") and any redistribution must be conditioned upon
20 * including a substantially similar Disclaimer requirement for further
21 * binary redistribution.
22 * 3. Neither the names of the above-listed copyright holders nor the names
23 * of any contributors may be used to endorse or promote products derived
24 * from this software without specific prior written permission.
25 *
26 * Alternatively, this software may be distributed under the terms of the
27 * GNU General Public License ("GPL") version 2 as published by the Free
28 * Software Foundation.
29 *
30 * NO WARRANTY
31 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
32 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
33 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
34 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
35 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
36 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
37 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
38 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
40 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
41 * POSSIBILITY OF SUCH DAMAGES.
42 */
43
44 #include "acpi.h"
45 #include "accommon.h"
46 #include "acevents.h"
47 #include "acinterp.h"
48
49 #define _COMPONENT ACPI_EVENTS
50 ACPI_MODULE_NAME ("evglock")
51
52 #if (!ACPI_REDUCED_HARDWARE) /* Entire module */
53
54 /* Local prototypes */
55
56 static UINT32
57 AcpiEvGlobalLockHandler (
58 void *Context);
59
60
61 /*******************************************************************************
62 *
63 * FUNCTION: AcpiEvInitGlobalLockHandler
64 *
65 * PARAMETERS: None
66 *
67 * RETURN: Status
68 *
69 * DESCRIPTION: Install a handler for the global lock release event
70 *
71 ******************************************************************************/
72
73 ACPI_STATUS
74 AcpiEvInitGlobalLockHandler (
75 void)
76 {
77 ACPI_STATUS Status;
78
79
80 ACPI_FUNCTION_TRACE (EvInitGlobalLockHandler);
81
82
83 /* If Hardware Reduced flag is set, there is no global lock */
84
85 if (AcpiGbl_ReducedHardware)
86 {
87 return_ACPI_STATUS (AE_OK);
88 }
89
90 /* Attempt installation of the global lock handler */
91
92 Status = AcpiInstallFixedEventHandler (ACPI_EVENT_GLOBAL,
93 AcpiEvGlobalLockHandler, NULL);
94
95 /*
96 * If the global lock does not exist on this platform, the attempt to
97 * enable GBL_STATUS will fail (the GBL_ENABLE bit will not stick).
98 * Map to AE_OK, but mark global lock as not present. Any attempt to
99 * actually use the global lock will be flagged with an error.
100 */
101 AcpiGbl_GlobalLockPresent = FALSE;
102 if (Status == AE_NO_HARDWARE_RESPONSE)
103 {
104 ACPI_ERROR ((AE_INFO,
105 "No response from Global Lock hardware, disabling lock"));
106
107 return_ACPI_STATUS (AE_OK);
108 }
109
110 Status = AcpiOsCreateLock (&AcpiGbl_GlobalLockPendingLock);
111 if (ACPI_FAILURE (Status))
112 {
113 return_ACPI_STATUS (Status);
114 }
115
116 AcpiGbl_GlobalLockPending = FALSE;
117 AcpiGbl_GlobalLockPresent = TRUE;
118 return_ACPI_STATUS (Status);
119 }
120
121
122 /*******************************************************************************
123 *
124 * FUNCTION: AcpiEvRemoveGlobalLockHandler
125 *
126 * PARAMETERS: None
127 *
128 * RETURN: Status
129 *
130 * DESCRIPTION: Remove the handler for the Global Lock
131 *
132 ******************************************************************************/
133
134 ACPI_STATUS
135 AcpiEvRemoveGlobalLockHandler (
136 void)
137 {
138 ACPI_STATUS Status;
139
140
141 ACPI_FUNCTION_TRACE (EvRemoveGlobalLockHandler);
142
143 AcpiGbl_GlobalLockPresent = FALSE;
144 Status = AcpiRemoveFixedEventHandler (ACPI_EVENT_GLOBAL,
145 AcpiEvGlobalLockHandler);
146
147 AcpiOsDeleteLock (AcpiGbl_GlobalLockPendingLock);
148 return_ACPI_STATUS (Status);
149 }
150
151
152 /*******************************************************************************
153 *
154 * FUNCTION: AcpiEvGlobalLockHandler
155 *
156 * PARAMETERS: Context - From thread interface, not used
157 *
158 * RETURN: ACPI_INTERRUPT_HANDLED
159 *
160 * DESCRIPTION: Invoked directly from the SCI handler when a global lock
161 * release interrupt occurs. If there is actually a pending
162 * request for the lock, signal the waiting thread.
163 *
164 ******************************************************************************/
165
166 static UINT32
167 AcpiEvGlobalLockHandler (
168 void *Context)
169 {
170 ACPI_STATUS Status;
171 ACPI_CPU_FLAGS Flags;
172
173
174 Flags = AcpiOsAcquireLock (AcpiGbl_GlobalLockPendingLock);
175
176 /*
177 * If a request for the global lock is not actually pending,
178 * we are done. This handles "spurious" global lock interrupts
179 * which are possible (and have been seen) with bad BIOSs.
180 */
181 if (!AcpiGbl_GlobalLockPending)
182 {
183 goto CleanupAndExit;
184 }
185
186 /*
187 * Send a unit to the global lock semaphore. The actual acquisition
188 * of the global lock will be performed by the waiting thread.
189 */
190 Status = AcpiOsSignalSemaphore (AcpiGbl_GlobalLockSemaphore, 1);
191 if (ACPI_FAILURE (Status))
192 {
193 ACPI_ERROR ((AE_INFO, "Could not signal Global Lock semaphore"));
194 }
195
196 AcpiGbl_GlobalLockPending = FALSE;
197
198
199 CleanupAndExit:
200
201 AcpiOsReleaseLock (AcpiGbl_GlobalLockPendingLock, Flags);
202 return (ACPI_INTERRUPT_HANDLED);
203 }
204
205
206 /******************************************************************************
207 *
208 * FUNCTION: AcpiEvAcquireGlobalLock
209 *
210 * PARAMETERS: Timeout - Max time to wait for the lock, in millisec.
211 *
212 * RETURN: Status
213 *
214 * DESCRIPTION: Attempt to gain ownership of the Global Lock.
215 *
216 * MUTEX: Interpreter must be locked
217 *
218 * Note: The original implementation allowed multiple threads to "acquire" the
219 * Global Lock, and the OS would hold the lock until the last thread had
220 * released it. However, this could potentially starve the BIOS out of the
221 * lock, especially in the case where there is a tight handshake between the
222 * Embedded Controller driver and the BIOS. Therefore, this implementation
223 * allows only one thread to acquire the HW Global Lock at a time, and makes
224 * the global lock appear as a standard mutex on the OS side.
225 *
226 *****************************************************************************/
227
228 ACPI_STATUS
229 AcpiEvAcquireGlobalLock (
230 UINT16 Timeout)
231 {
232 ACPI_CPU_FLAGS Flags;
233 ACPI_STATUS Status;
234 BOOLEAN Acquired = FALSE;
235
236
237 ACPI_FUNCTION_TRACE (EvAcquireGlobalLock);
238
239
240 /*
241 * Only one thread can acquire the GL at a time, the GlobalLockMutex
242 * enforces this. This interface releases the interpreter if we must wait.
243 */
244 Status = AcpiExSystemWaitMutex (AcpiGbl_GlobalLockMutex->Mutex.OsMutex,
245 Timeout);
246 if (ACPI_FAILURE (Status))
247 {
248 return_ACPI_STATUS (Status);
249 }
250
251 /*
252 * Update the global lock handle and check for wraparound. The handle is
253 * only used for the external global lock interfaces, but it is updated
254 * here to properly handle the case where a single thread may acquire the
255 * lock via both the AML and the AcpiAcquireGlobalLock interfaces. The
256 * handle is therefore updated on the first acquire from a given thread
257 * regardless of where the acquisition request originated.
258 */
259 AcpiGbl_GlobalLockHandle++;
260 if (AcpiGbl_GlobalLockHandle == 0)
261 {
262 AcpiGbl_GlobalLockHandle = 1;
263 }
264
265 /*
266 * Make sure that a global lock actually exists. If not, just
267 * treat the lock as a standard mutex.
268 */
269 if (!AcpiGbl_GlobalLockPresent)
270 {
271 AcpiGbl_GlobalLockAcquired = TRUE;
272 return_ACPI_STATUS (AE_OK);
273 }
274
275 Flags = AcpiOsAcquireLock (AcpiGbl_GlobalLockPendingLock);
276
277 do
278 {
279 /* Attempt to acquire the actual hardware lock */
280
281 ACPI_ACQUIRE_GLOBAL_LOCK (AcpiGbl_FACS, Acquired);
282 if (Acquired)
283 {
284 AcpiGbl_GlobalLockAcquired = TRUE;
285 ACPI_DEBUG_PRINT ((ACPI_DB_EXEC,
286 "Acquired hardware Global Lock\n"));
287 break;
288 }
289
290 /*
291 * Did not get the lock. The pending bit was set above, and
292 * we must now wait until we receive the global lock
293 * released interrupt.
294 */
295 AcpiGbl_GlobalLockPending = TRUE;
296 AcpiOsReleaseLock (AcpiGbl_GlobalLockPendingLock, Flags);
297
298 ACPI_DEBUG_PRINT ((ACPI_DB_EXEC,
299 "Waiting for hardware Global Lock\n"));
300
301 /*
302 * Wait for handshake with the global lock interrupt handler.
303 * This interface releases the interpreter if we must wait.
304 */
305 Status = AcpiExSystemWaitSemaphore (AcpiGbl_GlobalLockSemaphore,
306 ACPI_WAIT_FOREVER);
307
308 Flags = AcpiOsAcquireLock (AcpiGbl_GlobalLockPendingLock);
309
310 } while (ACPI_SUCCESS (Status));
311
312 AcpiGbl_GlobalLockPending = FALSE;
313 AcpiOsReleaseLock (AcpiGbl_GlobalLockPendingLock, Flags);
314
315 return_ACPI_STATUS (Status);
316 }
317
318
319 /*******************************************************************************
320 *
321 * FUNCTION: AcpiEvReleaseGlobalLock
322 *
323 * PARAMETERS: None
324 *
325 * RETURN: Status
326 *
327 * DESCRIPTION: Releases ownership of the Global Lock.
328 *
329 ******************************************************************************/
330
331 ACPI_STATUS
332 AcpiEvReleaseGlobalLock (
333 void)
334 {
335 BOOLEAN Pending = FALSE;
336 ACPI_STATUS Status = AE_OK;
337
338
339 ACPI_FUNCTION_TRACE (EvReleaseGlobalLock);
340
341
342 /* Lock must be already acquired */
343
344 if (!AcpiGbl_GlobalLockAcquired)
345 {
346 ACPI_WARNING ((AE_INFO,
347 "Cannot release the ACPI Global Lock, it has not been acquired"));
348 return_ACPI_STATUS (AE_NOT_ACQUIRED);
349 }
350
351 if (AcpiGbl_GlobalLockPresent)
352 {
353 /* Allow any thread to release the lock */
354
355 ACPI_RELEASE_GLOBAL_LOCK (AcpiGbl_FACS, Pending);
356
357 /*
358 * If the pending bit was set, we must write GBL_RLS to the control
359 * register
360 */
361 if (Pending)
362 {
363 Status = AcpiWriteBitRegister (
364 ACPI_BITREG_GLOBAL_LOCK_RELEASE, ACPI_ENABLE_EVENT);
365 }
366
367 ACPI_DEBUG_PRINT ((ACPI_DB_EXEC, "Released hardware Global Lock\n"));
368 }
369
370 AcpiGbl_GlobalLockAcquired = FALSE;
371
372 /* Release the local GL mutex */
373
374 AcpiOsReleaseMutex (AcpiGbl_GlobalLockMutex->Mutex.OsMutex);
375 return_ACPI_STATUS (Status);
376 }
377
378 #endif /* !ACPI_REDUCED_HARDWARE */