evglock.c revision 245582 
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 <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    return_ACPI_STATUS (Status);
148}
149
150
151/*******************************************************************************
152 *
153 * FUNCTION:    AcpiEvGlobalLockHandler
154 *
155 * PARAMETERS:  Context         - From thread interface, not used
156 *
157 * RETURN:      ACPI_INTERRUPT_HANDLED
158 *
159 * DESCRIPTION: Invoked directly from the SCI handler when a global lock
160 *              release interrupt occurs. If there is actually a pending
161 *              request for the lock, signal the waiting thread.
162 *
163 ******************************************************************************/
164
165static UINT32
166AcpiEvGlobalLockHandler (
167    void                    *Context)
168{
169    ACPI_STATUS             Status;
170    ACPI_CPU_FLAGS          Flags;
171
172
173    Flags = AcpiOsAcquireLock (AcpiGbl_GlobalLockPendingLock);
174
175    /*
176     * If a request for the global lock is not actually pending,
177     * we are done. This handles "spurious" global lock interrupts
178     * which are possible (and have been seen) with bad BIOSs.
179     */
180    if (!AcpiGbl_GlobalLockPending)
181    {
182        goto CleanupAndExit;
183    }
184
185    /*
186     * Send a unit to the global lock semaphore. The actual acquisition
187     * of the global lock will be performed by the waiting thread.
188     */
189    Status = AcpiOsSignalSemaphore (AcpiGbl_GlobalLockSemaphore, 1);
190    if (ACPI_FAILURE (Status))
191    {
192        ACPI_ERROR ((AE_INFO, "Could not signal Global Lock semaphore"));
193    }
194
195    AcpiGbl_GlobalLockPending = FALSE;
196
197
198CleanupAndExit:
199
200    AcpiOsReleaseLock (AcpiGbl_GlobalLockPendingLock, Flags);
201    return (ACPI_INTERRUPT_HANDLED);
202}
203
204
205/******************************************************************************
206 *
207 * FUNCTION:    AcpiEvAcquireGlobalLock
208 *
209 * PARAMETERS:  Timeout         - Max time to wait for the lock, in millisec.
210 *
211 * RETURN:      Status
212 *
213 * DESCRIPTION: Attempt to gain ownership of the Global Lock.
214 *
215 * MUTEX:       Interpreter must be locked
216 *
217 * Note: The original implementation allowed multiple threads to "acquire" the
218 * Global Lock, and the OS would hold the lock until the last thread had
219 * released it. However, this could potentially starve the BIOS out of the
220 * lock, especially in the case where there is a tight handshake between the
221 * Embedded Controller driver and the BIOS. Therefore, this implementation
222 * allows only one thread to acquire the HW Global Lock at a time, and makes
223 * the global lock appear as a standard mutex on the OS side.
224 *
225 *****************************************************************************/
226
227ACPI_STATUS
228AcpiEvAcquireGlobalLock (
229    UINT16                  Timeout)
230{
231    ACPI_CPU_FLAGS          Flags;
232    ACPI_STATUS             Status;
233    BOOLEAN                 Acquired = FALSE;
234
235
236    ACPI_FUNCTION_TRACE (EvAcquireGlobalLock);
237
238
239    /*
240     * Only one thread can acquire the GL at a time, the GlobalLockMutex
241     * enforces this. This interface releases the interpreter if we must wait.
242     */
243    Status = AcpiExSystemWaitMutex (AcpiGbl_GlobalLockMutex->Mutex.OsMutex,
244                Timeout);
245    if (ACPI_FAILURE (Status))
246    {
247        return_ACPI_STATUS (Status);
248    }
249
250    /*
251     * Update the global lock handle and check for wraparound. The handle is
252     * only used for the external global lock interfaces, but it is updated
253     * here to properly handle the case where a single thread may acquire the
254     * lock via both the AML and the AcpiAcquireGlobalLock interfaces. The
255     * handle is therefore updated on the first acquire from a given thread
256     * regardless of where the acquisition request originated.
257     */
258    AcpiGbl_GlobalLockHandle++;
259    if (AcpiGbl_GlobalLockHandle == 0)
260    {
261        AcpiGbl_GlobalLockHandle = 1;
262    }
263
264    /*
265     * Make sure that a global lock actually exists. If not, just
266     * treat the lock as a standard mutex.
267     */
268    if (!AcpiGbl_GlobalLockPresent)
269    {
270        AcpiGbl_GlobalLockAcquired = TRUE;
271        return_ACPI_STATUS (AE_OK);
272    }
273
274    Flags = AcpiOsAcquireLock (AcpiGbl_GlobalLockPendingLock);
275
276    do
277    {
278        /* Attempt to acquire the actual hardware lock */
279
280        ACPI_ACQUIRE_GLOBAL_LOCK (AcpiGbl_FACS, Acquired);
281        if (Acquired)
282        {
283            AcpiGbl_GlobalLockAcquired = TRUE;
284            ACPI_DEBUG_PRINT ((ACPI_DB_EXEC,
285                "Acquired hardware Global Lock\n"));
286            break;
287        }
288
289        /*
290         * Did not get the lock. The pending bit was set above, and
291         * we must now wait until we receive the global lock
292         * released interrupt.
293         */
294        AcpiGbl_GlobalLockPending = TRUE;
295        AcpiOsReleaseLock (AcpiGbl_GlobalLockPendingLock, Flags);
296
297        ACPI_DEBUG_PRINT ((ACPI_DB_EXEC,
298            "Waiting for hardware Global Lock\n"));
299
300        /*
301         * Wait for handshake with the global lock interrupt handler.
302         * This interface releases the interpreter if we must wait.
303         */
304        Status = AcpiExSystemWaitSemaphore (AcpiGbl_GlobalLockSemaphore,
305                    ACPI_WAIT_FOREVER);
306
307        Flags = AcpiOsAcquireLock (AcpiGbl_GlobalLockPendingLock);
308
309    } while (ACPI_SUCCESS (Status));
310
311    AcpiGbl_GlobalLockPending = FALSE;
312    AcpiOsReleaseLock (AcpiGbl_GlobalLockPendingLock, Flags);
313
314    return_ACPI_STATUS (Status);
315}
316
317
318/*******************************************************************************
319 *
320 * FUNCTION:    AcpiEvReleaseGlobalLock
321 *
322 * PARAMETERS:  None
323 *
324 * RETURN:      Status
325 *
326 * DESCRIPTION: Releases ownership of the Global Lock.
327 *
328 ******************************************************************************/
329
330ACPI_STATUS
331AcpiEvReleaseGlobalLock (
332    void)
333{
334    BOOLEAN                 Pending = FALSE;
335    ACPI_STATUS             Status = AE_OK;
336
337
338    ACPI_FUNCTION_TRACE (EvReleaseGlobalLock);
339
340
341    /* Lock must be already acquired */
342
343    if (!AcpiGbl_GlobalLockAcquired)
344    {
345        ACPI_WARNING ((AE_INFO,
346            "Cannot release the ACPI Global Lock, it has not been acquired"));
347        return_ACPI_STATUS (AE_NOT_ACQUIRED);
348    }
349
350    if (AcpiGbl_GlobalLockPresent)
351    {
352        /* Allow any thread to release the lock */
353
354        ACPI_RELEASE_GLOBAL_LOCK (AcpiGbl_FACS, Pending);
355
356        /*
357         * If the pending bit was set, we must write GBL_RLS to the control
358         * register
359         */
360        if (Pending)
361        {
362            Status = AcpiWriteBitRegister (
363                        ACPI_BITREG_GLOBAL_LOCK_RELEASE, ACPI_ENABLE_EVENT);
364        }
365
366        ACPI_DEBUG_PRINT ((ACPI_DB_EXEC, "Released hardware Global Lock\n"));
367    }
368
369    AcpiGbl_GlobalLockAcquired = FALSE;
370
371    /* Release the local GL mutex */
372
373    AcpiOsReleaseMutex (AcpiGbl_GlobalLockMutex->Mutex.OsMutex);
374    return_ACPI_STATUS (Status);
375}
376
377#endif /* !ACPI_REDUCED_HARDWARE */
378