arch/all-pc/acpica/source/components/events/evglock.c

   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 */