1 /******************************************************************************
3 * Module Name: evglock - Global Lock support
5 *****************************************************************************/
7 /******************************************************************************
11 * Some or all of this work - Copyright (c) 1999 - 2011, Intel Corp.
12 * All rights reserved.
16 * 2.1. This is your license from Intel Corp. under its intellectual property
17 * rights. You may have additional license terms from the party that provided
18 * you this software, covering your right to use that party's intellectual
21 * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a
22 * copy of the source code appearing in this file ("Covered Code") an
23 * irrevocable, perpetual, worldwide license under Intel's copyrights in the
24 * base code distributed originally by Intel ("Original Intel Code") to copy,
25 * make derivatives, distribute, use and display any portion of the Covered
26 * Code in any form, with the right to sublicense such rights; and
28 * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent
29 * license (with the right to sublicense), under only those claims of Intel
30 * patents that are infringed by the Original Intel Code, to make, use, sell,
31 * offer to sell, and import the Covered Code and derivative works thereof
32 * solely to the minimum extent necessary to exercise the above copyright
33 * license, and in no event shall the patent license extend to any additions
34 * to or modifications of the Original Intel Code. No other license or right
35 * is granted directly or by implication, estoppel or otherwise;
37 * The above copyright and patent license is granted only if the following
42 * 3.1. Redistribution of Source with Rights to Further Distribute Source.
43 * Redistribution of source code of any substantial portion of the Covered
44 * Code or modification with rights to further distribute source must include
45 * the above Copyright Notice, the above License, this list of Conditions,
46 * and the following Disclaimer and Export Compliance provision. In addition,
47 * Licensee must cause all Covered Code to which Licensee contributes to
48 * contain a file documenting the changes Licensee made to create that Covered
49 * Code and the date of any change. Licensee must include in that file the
50 * documentation of any changes made by any predecessor Licensee. Licensee
51 * must include a prominent statement that the modification is derived,
52 * directly or indirectly, from Original Intel Code.
54 * 3.2. Redistribution of Source with no Rights to Further Distribute Source.
55 * Redistribution of source code of any substantial portion of the Covered
56 * Code or modification without rights to further distribute source must
57 * include the following Disclaimer and Export Compliance provision in the
58 * documentation and/or other materials provided with distribution. In
59 * addition, Licensee may not authorize further sublicense of source of any
60 * portion of the Covered Code, and must include terms to the effect that the
61 * license from Licensee to its licensee is limited to the intellectual
62 * property embodied in the software Licensee provides to its licensee, and
63 * not to intellectual property embodied in modifications its licensee may
66 * 3.3. Redistribution of Executable. Redistribution in executable form of any
67 * substantial portion of the Covered Code or modification must reproduce the
68 * above Copyright Notice, and the following Disclaimer and Export Compliance
69 * provision in the documentation and/or other materials provided with the
72 * 3.4. Intel retains all right, title, and interest in and to the Original
75 * 3.5. Neither the name Intel nor any other trademark owned or controlled by
76 * Intel shall be used in advertising or otherwise to promote the sale, use or
77 * other dealings in products derived from or relating to the Covered Code
78 * without prior written authorization from Intel.
80 * 4. Disclaimer and Export Compliance
82 * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED
83 * HERE. ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE
84 * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT, ASSISTANCE,
85 * INSTALLATION, TRAINING OR OTHER SERVICES. INTEL WILL NOT PROVIDE ANY
86 * UPDATES, ENHANCEMENTS OR EXTENSIONS. INTEL SPECIFICALLY DISCLAIMS ANY
87 * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A
90 * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES
91 * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR
92 * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT,
93 * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY
94 * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL
95 * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES. THESE LIMITATIONS
96 * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY
99 * 4.3. Licensee shall not export, either directly or indirectly, any of this
100 * software or system incorporating such software without first obtaining any
101 * required license or other approval from the U. S. Department of Commerce or
102 * any other agency or department of the United States Government. In the
103 * event Licensee exports any such software from the United States or
104 * re-exports any such software from a foreign destination, Licensee shall
105 * ensure that the distribution and export/re-export of the software is in
106 * compliance with all laws, regulations, orders, or other restrictions of the
107 * U.S. Export Administration Regulations. Licensee agrees that neither it nor
108 * any of its subsidiaries will export/re-export any technical data, process,
109 * software, or service, directly or indirectly, to any country for which the
110 * United States government or any agency thereof requires an export license,
111 * other governmental approval, or letter of assurance, without first obtaining
112 * such license, approval or letter.
114 *****************************************************************************/
117 #include "accommon.h"
118 #include "acevents.h"
119 #include "acinterp.h"
121 #define _COMPONENT ACPI_EVENTS
122 ACPI_MODULE_NAME ("evglock")
125 /* Local prototypes */
128 AcpiEvGlobalLockHandler (
132 /*******************************************************************************
134 * FUNCTION: AcpiEvInitGlobalLockHandler
140 * DESCRIPTION: Install a handler for the global lock release event
142 ******************************************************************************/
145 AcpiEvInitGlobalLockHandler (
151 ACPI_FUNCTION_TRACE (EvInitGlobalLockHandler
);
154 /* Attempt installation of the global lock handler */
156 Status
= AcpiInstallFixedEventHandler (ACPI_EVENT_GLOBAL
,
157 AcpiEvGlobalLockHandler
, NULL
);
160 * If the global lock does not exist on this platform, the attempt to
161 * enable GBL_STATUS will fail (the GBL_ENABLE bit will not stick).
162 * Map to AE_OK, but mark global lock as not present. Any attempt to
163 * actually use the global lock will be flagged with an error.
165 AcpiGbl_GlobalLockPresent
= FALSE
;
166 if (Status
== AE_NO_HARDWARE_RESPONSE
)
168 ACPI_ERROR ((AE_INFO
,
169 "No response from Global Lock hardware, disabling lock"));
171 return_ACPI_STATUS (AE_OK
);
174 Status
= AcpiOsCreateLock (&AcpiGbl_GlobalLockPendingLock
);
175 if (ACPI_FAILURE (Status
))
177 return_ACPI_STATUS (Status
);
180 AcpiGbl_GlobalLockPending
= FALSE
;
181 AcpiGbl_GlobalLockPresent
= TRUE
;
182 return_ACPI_STATUS (Status
);
186 /*******************************************************************************
188 * FUNCTION: AcpiEvRemoveGlobalLockHandler
194 * DESCRIPTION: Remove the handler for the Global Lock
196 ******************************************************************************/
199 AcpiEvRemoveGlobalLockHandler (
205 ACPI_FUNCTION_TRACE (EvRemoveGlobalLockHandler
);
207 AcpiGbl_GlobalLockPresent
= FALSE
;
208 Status
= AcpiRemoveFixedEventHandler (ACPI_EVENT_GLOBAL
,
209 AcpiEvGlobalLockHandler
);
211 return_ACPI_STATUS (Status
);
215 /*******************************************************************************
217 * FUNCTION: AcpiEvGlobalLockHandler
219 * PARAMETERS: Context - From thread interface, not used
221 * RETURN: ACPI_INTERRUPT_HANDLED
223 * DESCRIPTION: Invoked directly from the SCI handler when a global lock
224 * release interrupt occurs. If there is actually a pending
225 * request for the lock, signal the waiting thread.
227 ******************************************************************************/
230 AcpiEvGlobalLockHandler (
234 ACPI_CPU_FLAGS Flags
;
237 Flags
= AcpiOsAcquireLock (AcpiGbl_GlobalLockPendingLock
);
240 * If a request for the global lock is not actually pending,
241 * we are done. This handles "spurious" global lock interrupts
242 * which are possible (and have been seen) with bad BIOSs.
244 if (!AcpiGbl_GlobalLockPending
)
250 * Send a unit to the global lock semaphore. The actual acquisition
251 * of the global lock will be performed by the waiting thread.
253 Status
= AcpiOsSignalSemaphore (AcpiGbl_GlobalLockSemaphore
, 1);
254 if (ACPI_FAILURE (Status
))
256 ACPI_ERROR ((AE_INFO
, "Could not signal Global Lock semaphore"));
259 AcpiGbl_GlobalLockPending
= FALSE
;
264 AcpiOsReleaseLock (AcpiGbl_GlobalLockPendingLock
, Flags
);
265 return (ACPI_INTERRUPT_HANDLED
);
269 /******************************************************************************
271 * FUNCTION: AcpiEvAcquireGlobalLock
273 * PARAMETERS: Timeout - Max time to wait for the lock, in millisec.
277 * DESCRIPTION: Attempt to gain ownership of the Global Lock.
279 * MUTEX: Interpreter must be locked
281 * Note: The original implementation allowed multiple threads to "acquire" the
282 * Global Lock, and the OS would hold the lock until the last thread had
283 * released it. However, this could potentially starve the BIOS out of the
284 * lock, especially in the case where there is a tight handshake between the
285 * Embedded Controller driver and the BIOS. Therefore, this implementation
286 * allows only one thread to acquire the HW Global Lock at a time, and makes
287 * the global lock appear as a standard mutex on the OS side.
289 *****************************************************************************/
292 AcpiEvAcquireGlobalLock (
295 ACPI_CPU_FLAGS Flags
;
297 BOOLEAN Acquired
= FALSE
;
300 ACPI_FUNCTION_TRACE (EvAcquireGlobalLock
);
304 * Only one thread can acquire the GL at a time, the GlobalLockMutex
305 * enforces this. This interface releases the interpreter if we must wait.
307 Status
= AcpiExSystemWaitMutex (AcpiGbl_GlobalLockMutex
->Mutex
.OsMutex
,
309 if (ACPI_FAILURE (Status
))
311 return_ACPI_STATUS (Status
);
315 * Update the global lock handle and check for wraparound. The handle is
316 * only used for the external global lock interfaces, but it is updated
317 * here to properly handle the case where a single thread may acquire the
318 * lock via both the AML and the AcpiAcquireGlobalLock interfaces. The
319 * handle is therefore updated on the first acquire from a given thread
320 * regardless of where the acquisition request originated.
322 AcpiGbl_GlobalLockHandle
++;
323 if (AcpiGbl_GlobalLockHandle
== 0)
325 AcpiGbl_GlobalLockHandle
= 1;
329 * Make sure that a global lock actually exists. If not, just
330 * treat the lock as a standard mutex.
332 if (!AcpiGbl_GlobalLockPresent
)
334 AcpiGbl_GlobalLockAcquired
= TRUE
;
335 return_ACPI_STATUS (AE_OK
);
338 Flags
= AcpiOsAcquireLock (AcpiGbl_GlobalLockPendingLock
);
342 /* Attempt to acquire the actual hardware lock */
344 ACPI_ACQUIRE_GLOBAL_LOCK (AcpiGbl_FACS
, Acquired
);
347 AcpiGbl_GlobalLockAcquired
= TRUE
;
348 ACPI_DEBUG_PRINT ((ACPI_DB_EXEC
,
349 "Acquired hardware Global Lock\n"));
354 * Did not get the lock. The pending bit was set above, and
355 * we must now wait until we receive the global lock
356 * released interrupt.
358 AcpiGbl_GlobalLockPending
= TRUE
;
359 AcpiOsReleaseLock (AcpiGbl_GlobalLockPendingLock
, Flags
);
361 ACPI_DEBUG_PRINT ((ACPI_DB_EXEC
,
362 "Waiting for hardware Global Lock\n"));
365 * Wait for handshake with the global lock interrupt handler.
366 * This interface releases the interpreter if we must wait.
368 Status
= AcpiExSystemWaitSemaphore (AcpiGbl_GlobalLockSemaphore
,
371 Flags
= AcpiOsAcquireLock (AcpiGbl_GlobalLockPendingLock
);
373 } while (ACPI_SUCCESS (Status
));
375 AcpiGbl_GlobalLockPending
= FALSE
;
376 AcpiOsReleaseLock (AcpiGbl_GlobalLockPendingLock
, Flags
);
378 return_ACPI_STATUS (Status
);
382 /*******************************************************************************
384 * FUNCTION: AcpiEvReleaseGlobalLock
390 * DESCRIPTION: Releases ownership of the Global Lock.
392 ******************************************************************************/
395 AcpiEvReleaseGlobalLock (
398 BOOLEAN Pending
= FALSE
;
399 ACPI_STATUS Status
= AE_OK
;
402 ACPI_FUNCTION_TRACE (EvReleaseGlobalLock
);
405 /* Lock must be already acquired */
407 if (!AcpiGbl_GlobalLockAcquired
)
409 ACPI_WARNING ((AE_INFO
,
410 "Cannot release the ACPI Global Lock, it has not been acquired"));
411 return_ACPI_STATUS (AE_NOT_ACQUIRED
);
414 if (AcpiGbl_GlobalLockPresent
)
416 /* Allow any thread to release the lock */
418 ACPI_RELEASE_GLOBAL_LOCK (AcpiGbl_FACS
, Pending
);
421 * If the pending bit was set, we must write GBL_RLS to the control
426 Status
= AcpiWriteBitRegister (
427 ACPI_BITREG_GLOBAL_LOCK_RELEASE
, ACPI_ENABLE_EVENT
);
430 ACPI_DEBUG_PRINT ((ACPI_DB_EXEC
, "Released hardware Global Lock\n"));
433 AcpiGbl_GlobalLockAcquired
= FALSE
;
435 /* Release the local GL mutex */
437 AcpiOsReleaseMutex (AcpiGbl_GlobalLockMutex
->Mutex
.OsMutex
);
438 return_ACPI_STATUS (Status
);