drivers/bus/acpi/acpica/events/evglock.c

   1 /******************************************************************************
   2  *
   3  * Module Name: evglock - Global Lock support
   4  *
   5  *****************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2017, 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
 144     AcpiGbl_GlobalLockPresent = FALSE;
 145     Status = AcpiRemoveFixedEventHandler (ACPI_EVENT_GLOBAL,
 146         AcpiEvGlobalLockHandler);
 147
 148     AcpiOsDeleteLock (AcpiGbl_GlobalLockPendingLock);
 149     return_ACPI_STATUS (Status);
 150 }
 151
 152
 153 /*******************************************************************************
 154  *
 155  * FUNCTION:    AcpiEvGlobalLockHandler
 156  *
 157  * PARAMETERS:  Context         - From thread interface, not used
 158  *
 159  * RETURN:      ACPI_INTERRUPT_HANDLED
 160  *
 161  * DESCRIPTION: Invoked directly from the SCI handler when a global lock
 162  *              release interrupt occurs. If there is actually a pending
 163  *              request for the lock, signal the waiting thread.
 164  *
 165  ******************************************************************************/
 166
 167 static UINT32
 168 AcpiEvGlobalLockHandler (
 169     void                    *Context)
 170 {
 171     ACPI_STATUS             Status;
 172     ACPI_CPU_FLAGS          Flags;
 173
 174
 175     Flags = AcpiOsAcquireLock (AcpiGbl_GlobalLockPendingLock);
 176
 177     /*
 178      * If a request for the global lock is not actually pending,
 179      * we are done. This handles "spurious" global lock interrupts
 180      * which are possible (and have been seen) with bad BIOSs.
 181      */
 182     if (!AcpiGbl_GlobalLockPending)
 183     {
 184         goto CleanupAndExit;
 185     }
 186
 187     /*
 188      * Send a unit to the global lock semaphore. The actual acquisition
 189      * of the global lock will be performed by the waiting thread.
 190      */
 191     Status = AcpiOsSignalSemaphore (AcpiGbl_GlobalLockSemaphore, 1);
 192     if (ACPI_FAILURE (Status))
 193     {
 194         ACPI_ERROR ((AE_INFO, "Could not signal Global Lock semaphore"));
 195     }
 196
 197     AcpiGbl_GlobalLockPending = FALSE;
 198
 199
 200 CleanupAndExit:
 201
 202     AcpiOsReleaseLock (AcpiGbl_GlobalLockPendingLock, Flags);
 203     return (ACPI_INTERRUPT_HANDLED);
 204 }
 205
 206
 207 /******************************************************************************
 208  *
 209  * FUNCTION:    AcpiEvAcquireGlobalLock
 210  *
 211  * PARAMETERS:  Timeout         - Max time to wait for the lock, in millisec.
 212  *
 213  * RETURN:      Status
 214  *
 215  * DESCRIPTION: Attempt to gain ownership of the Global Lock.
 216  *
 217  * MUTEX:       Interpreter must be locked
 218  *
 219  * Note: The original implementation allowed multiple threads to "acquire" the
 220  * Global Lock, and the OS would hold the lock until the last thread had
 221  * released it. However, this could potentially starve the BIOS out of the
 222  * lock, especially in the case where there is a tight handshake between the
 223  * Embedded Controller driver and the BIOS. Therefore, this implementation
 224  * allows only one thread to acquire the HW Global Lock at a time, and makes
 225  * the global lock appear as a standard mutex on the OS side.
 226  *
 227  *****************************************************************************/
 228
 229 ACPI_STATUS
 230 AcpiEvAcquireGlobalLock (
 231     UINT16                  Timeout)
 232 {
 233     ACPI_CPU_FLAGS          Flags;
 234     ACPI_STATUS             Status;
 235     BOOLEAN                 Acquired = FALSE;
 236
 237
 238     ACPI_FUNCTION_TRACE (EvAcquireGlobalLock);
 239
 240
 241     /*
 242      * Only one thread can acquire the GL at a time, the GlobalLockMutex
 243      * enforces this. This interface releases the interpreter if we must wait.
 244      */
 245     Status = AcpiExSystemWaitMutex (AcpiGbl_GlobalLockMutex->Mutex.OsMutex,
 246                 Timeout);
 247     if (ACPI_FAILURE (Status))
 248     {
 249         return_ACPI_STATUS (Status);
 250     }
 251
 252     /*
 253      * Update the global lock handle and check for wraparound. The handle is
 254      * only used for the external global lock interfaces, but it is updated
 255      * here to properly handle the case where a single thread may acquire the
 256      * lock via both the AML and the AcpiAcquireGlobalLock interfaces. The
 257      * handle is therefore updated on the first acquire from a given thread
 258      * regardless of where the acquisition request originated.
 259      */
 260     AcpiGbl_GlobalLockHandle++;
 261     if (AcpiGbl_GlobalLockHandle == 0)
 262     {
 263         AcpiGbl_GlobalLockHandle = 1;
 264     }
 265
 266     /*
 267      * Make sure that a global lock actually exists. If not, just
 268      * treat the lock as a standard mutex.
 269      */
 270     if (!AcpiGbl_GlobalLockPresent)
 271     {
 272         AcpiGbl_GlobalLockAcquired = TRUE;
 273         return_ACPI_STATUS (AE_OK);
 274     }
 275
 276     Flags = AcpiOsAcquireLock (AcpiGbl_GlobalLockPendingLock);
 277
 278     do
 279     {
 280         /* Attempt to acquire the actual hardware lock */
 281
 282         ACPI_ACQUIRE_GLOBAL_LOCK (AcpiGbl_FACS, Acquired);
 283         if (Acquired)
 284         {
 285             AcpiGbl_GlobalLockAcquired = TRUE;
 286             ACPI_DEBUG_PRINT ((ACPI_DB_EXEC,
 287                 "Acquired hardware Global Lock\n"));
 288             break;
 289         }
 290
 291         /*
 292          * Did not get the lock. The pending bit was set above, and
 293          * we must now wait until we receive the global lock
 294          * released interrupt.
 295          */
 296         AcpiGbl_GlobalLockPending = TRUE;
 297         AcpiOsReleaseLock (AcpiGbl_GlobalLockPendingLock, Flags);
 298
 299         ACPI_DEBUG_PRINT ((ACPI_DB_EXEC,
 300             "Waiting for hardware Global Lock\n"));
 301
 302         /*
 303          * Wait for handshake with the global lock interrupt handler.
 304          * This interface releases the interpreter if we must wait.
 305          */
 306         Status = AcpiExSystemWaitSemaphore (
 307             AcpiGbl_GlobalLockSemaphore, ACPI_WAIT_FOREVER);
 308
 309         Flags = AcpiOsAcquireLock (AcpiGbl_GlobalLockPendingLock);
 310
 311     } while (ACPI_SUCCESS (Status));
 312
 313     AcpiGbl_GlobalLockPending = FALSE;
 314     AcpiOsReleaseLock (AcpiGbl_GlobalLockPendingLock, Flags);
 315
 316     return_ACPI_STATUS (Status);
 317 }
 318
 319
 320 /*******************************************************************************
 321  *
 322  * FUNCTION:    AcpiEvReleaseGlobalLock
 323  *
 324  * PARAMETERS:  None
 325  *
 326  * RETURN:      Status
 327  *
 328  * DESCRIPTION: Releases ownership of the Global Lock.
 329  *
 330  ******************************************************************************/
 331
 332 ACPI_STATUS
 333 AcpiEvReleaseGlobalLock (
 334     void)
 335 {
 336     BOOLEAN                 Pending = FALSE;
 337     ACPI_STATUS             Status = AE_OK;
 338
 339
 340     ACPI_FUNCTION_TRACE (EvReleaseGlobalLock);
 341
 342
 343     /* Lock must be already acquired */
 344
 345     if (!AcpiGbl_GlobalLockAcquired)
 346     {
 347         ACPI_WARNING ((AE_INFO,
 348             "Cannot release the ACPI Global Lock, it has not been acquired"));
 349         return_ACPI_STATUS (AE_NOT_ACQUIRED);
 350     }
 351
 352     if (AcpiGbl_GlobalLockPresent)
 353     {
 354         /* Allow any thread to release the lock */
 355
 356         ACPI_RELEASE_GLOBAL_LOCK (AcpiGbl_FACS, Pending);
 357
 358         /*
 359          * If the pending bit was set, we must write GBL_RLS to the control
 360          * register
 361          */
 362         if (Pending)
 363         {
 364             Status = AcpiWriteBitRegister (
 365                 ACPI_BITREG_GLOBAL_LOCK_RELEASE, ACPI_ENABLE_EVENT);
 366         }
 367
 368         ACPI_DEBUG_PRINT ((ACPI_DB_EXEC, "Released hardware Global Lock\n"));
 369     }
 370
 371     AcpiGbl_GlobalLockAcquired = FALSE;
 372
 373     /* Release the local GL mutex */
 374
 375     AcpiOsReleaseMutex (AcpiGbl_GlobalLockMutex->Mutex.OsMutex);
 376     return_ACPI_STATUS (Status);
 377 }
 378
 379 #endif /* !ACPI_REDUCED_HARDWARE */