1 /****************************************************************************** 2 * 3 * Module Name: evglock - Global Lock support 4 * 5 *****************************************************************************/ 6 7 /* 8 * Copyright (C) 2000 - 2012, 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 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 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 ******************************************************************************/ 164 165 static UINT32 166 AcpiEvGlobalLockHandler ( 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; 196 197 198 CleanupAndExit: 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 *****************************************************************************/ 226 227 ACPI_STATUS 228 AcpiEvAcquireGlobalLock ( 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 ******************************************************************************/ 329 330 ACPI_STATUS 331 AcpiEvReleaseGlobalLock ( 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