evglock.c revision 281075 
1/******************************************************************************
2 *
3 * Module Name: evglock - Global Lock support
4 *
5 *****************************************************************************/
6
7/*
8 * Copyright (C) 2000 - 2015, 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 <contrib/dev/acpica/include/acpi.h>
45#include <contrib/dev/acpica/include/accommon.h>
46#include <contrib/dev/acpica/include/acevents.h>
47#include <contrib/dev/acpica/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
56static UINT32
57AcpiEvGlobalLockHandler (
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
73ACPI_STATUS
74AcpiEvInitGlobalLockHandler (
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
134ACPI_STATUS
135AcpiEvRemoveGlobalLockHandler (
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
166static UINT32
167AcpiEvGlobalLockHandler (
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
199CleanupAndExit:
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
228ACPI_STATUS
229AcpiEvAcquireGlobalLock (
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
331ACPI_STATUS
332AcpiEvReleaseGlobalLock (
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 */
379