diff options
Diffstat (limited to 'drivers/acpi/events/evmisc.c')
| -rw-r--r-- | drivers/acpi/events/evmisc.c | 202 |
1 files changed, 115 insertions, 87 deletions
diff --git a/drivers/acpi/events/evmisc.c b/drivers/acpi/events/evmisc.c index ee2a10bf907..1b784ffe54c 100644 --- a/drivers/acpi/events/evmisc.c +++ b/drivers/acpi/events/evmisc.c @@ -5,7 +5,7 @@ *****************************************************************************/ /* - * Copyright (C) 2000 - 2006, R. Byron Moore + * Copyright (C) 2000 - 2007, R. Byron Moore * All rights reserved. * * Redistribution and use in source and binary forms, with or without @@ -63,14 +63,18 @@ static const char *acpi_notify_value_names[] = { }; #endif +/* Pointer to FACS needed for the Global Lock */ + +static struct acpi_table_facs *facs = NULL; + /* Local prototypes */ static void ACPI_SYSTEM_XFACE acpi_ev_notify_dispatch(void *context); -static void ACPI_SYSTEM_XFACE acpi_ev_global_lock_thread(void *context); - static u32 acpi_ev_global_lock_handler(void *context); +static acpi_status acpi_ev_remove_global_lock_handler(void); + /******************************************************************************* * * FUNCTION: acpi_ev_is_notify_object @@ -282,68 +286,45 @@ static void ACPI_SYSTEM_XFACE acpi_ev_notify_dispatch(void *context) /******************************************************************************* * - * FUNCTION: acpi_ev_global_lock_thread - * - * PARAMETERS: Context - From thread interface, not used - * - * RETURN: None - * - * DESCRIPTION: Invoked by SCI interrupt handler upon acquisition of the - * Global Lock. Simply signal all threads that are waiting - * for the lock. - * - ******************************************************************************/ - -static void ACPI_SYSTEM_XFACE acpi_ev_global_lock_thread(void *context) -{ - acpi_status status; - - /* Signal threads that are waiting for the lock */ - - if (acpi_gbl_global_lock_thread_count) { - - /* Send sufficient units to the semaphore */ - - status = - acpi_os_signal_semaphore(acpi_gbl_global_lock_semaphore, - acpi_gbl_global_lock_thread_count); - if (ACPI_FAILURE(status)) { - ACPI_ERROR((AE_INFO, - "Could not signal Global Lock semaphore")); - } - } -} - -/******************************************************************************* - * * FUNCTION: acpi_ev_global_lock_handler * * PARAMETERS: Context - From thread interface, not used * - * RETURN: ACPI_INTERRUPT_HANDLED or ACPI_INTERRUPT_NOT_HANDLED + * RETURN: ACPI_INTERRUPT_HANDLED * * DESCRIPTION: Invoked directly from the SCI handler when a global lock - * release interrupt occurs. Grab the global lock and queue - * the global lock thread for execution + * release interrupt occurs. Attempt to acquire the global lock, + * if successful, signal the thread waiting for the lock. + * + * NOTE: Assumes that the semaphore can be signaled from interrupt level. If + * this is not possible for some reason, a separate thread will have to be + * scheduled to do this. * ******************************************************************************/ static u32 acpi_ev_global_lock_handler(void *context) { u8 acquired = FALSE; - acpi_status status; /* - * Attempt to get the lock + * Attempt to get the lock. + * * If we don't get it now, it will be marked pending and we will * take another interrupt when it becomes free. */ - ACPI_ACQUIRE_GLOBAL_LOCK(acpi_gbl_common_fACS.global_lock, acquired); + ACPI_ACQUIRE_GLOBAL_LOCK(facs, acquired); if (acquired) { /* Got the lock, now wake all threads waiting for it */ + acpi_gbl_global_lock_acquired = TRUE; - acpi_ev_global_lock_thread(context); + /* Send a unit to the semaphore */ + + if (ACPI_FAILURE(acpi_os_signal_semaphore( + acpi_gbl_global_lock_semaphore, 1))) { + ACPI_ERROR((AE_INFO, + "Could not signal Global Lock semaphore")); + } } return (ACPI_INTERRUPT_HANDLED); @@ -367,6 +348,13 @@ acpi_status acpi_ev_init_global_lock_handler(void) ACPI_FUNCTION_TRACE(ev_init_global_lock_handler); + status = + acpi_get_table_by_index(ACPI_TABLE_INDEX_FACS, + (struct acpi_table_header **)&facs); + if (ACPI_FAILURE(status)) { + return_ACPI_STATUS(status); + } + acpi_gbl_global_lock_present = TRUE; status = acpi_install_fixed_event_handler(ACPI_EVENT_GLOBAL, acpi_ev_global_lock_handler, @@ -390,6 +378,31 @@ acpi_status acpi_ev_init_global_lock_handler(void) return_ACPI_STATUS(status); } +/******************************************************************************* + * + * FUNCTION: acpi_ev_remove_global_lock_handler + * + * PARAMETERS: None + * + * RETURN: Status + * + * DESCRIPTION: Remove the handler for the Global Lock + * + ******************************************************************************/ + +static acpi_status acpi_ev_remove_global_lock_handler(void) +{ + acpi_status status; + + ACPI_FUNCTION_TRACE(ev_remove_global_lock_handler); + + acpi_gbl_global_lock_present = FALSE; + status = acpi_remove_fixed_event_handler(ACPI_EVENT_GLOBAL, + acpi_ev_global_lock_handler); + + return_ACPI_STATUS(status); +} + /****************************************************************************** * * FUNCTION: acpi_ev_acquire_global_lock @@ -400,6 +413,16 @@ acpi_status acpi_ev_init_global_lock_handler(void) * * DESCRIPTION: Attempt to gain ownership of the Global Lock. * + * MUTEX: Interpreter must be locked + * + * Note: The original implementation allowed multiple threads to "acquire" the + * Global Lock, and the OS would hold the lock until the last thread had + * released it. However, this could potentially starve the BIOS out of the + * lock, especially in the case where there is a tight handshake between the + * Embedded Controller driver and the BIOS. Therefore, this implementation + * allows only one thread to acquire the HW Global Lock at a time, and makes + * the global lock appear as a standard mutex on the OS side. + * *****************************************************************************/ acpi_status acpi_ev_acquire_global_lock(u16 timeout) @@ -409,53 +432,51 @@ acpi_status acpi_ev_acquire_global_lock(u16 timeout) ACPI_FUNCTION_TRACE(ev_acquire_global_lock); -#ifndef ACPI_APPLICATION - /* Make sure that we actually have a global lock */ - - if (!acpi_gbl_global_lock_present) { - return_ACPI_STATUS(AE_NO_GLOBAL_LOCK); + /* + * Only one thread can acquire the GL at a time, the global_lock_mutex + * enforces this. This interface releases the interpreter if we must wait. + */ + status = acpi_ex_system_wait_mutex(acpi_gbl_global_lock_mutex, timeout); + if (ACPI_FAILURE(status)) { + return_ACPI_STATUS(status); } -#endif - - /* One more thread wants the global lock */ - - acpi_gbl_global_lock_thread_count++; /* - * If we (OS side vs. BIOS side) have the hardware lock already, - * we are done + * Make sure that a global lock actually exists. If not, just treat + * the lock as a standard mutex. */ - if (acpi_gbl_global_lock_acquired) { + if (!acpi_gbl_global_lock_present) { + acpi_gbl_global_lock_acquired = TRUE; return_ACPI_STATUS(AE_OK); } - /* We must acquire the actual hardware lock */ + /* Attempt to acquire the actual hardware lock */ - ACPI_ACQUIRE_GLOBAL_LOCK(acpi_gbl_common_fACS.global_lock, acquired); + ACPI_ACQUIRE_GLOBAL_LOCK(facs, acquired); if (acquired) { /* We got the lock */ ACPI_DEBUG_PRINT((ACPI_DB_EXEC, - "Acquired the HW Global Lock\n")); + "Acquired hardware Global Lock\n")); acpi_gbl_global_lock_acquired = TRUE; return_ACPI_STATUS(AE_OK); } /* - * Did not get the lock. The pending bit was set above, and we must now + * Did not get the lock. The pending bit was set above, and we must now * wait until we get the global lock released interrupt. */ - ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Waiting for the HW Global Lock\n")); + ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Waiting for hardware Global Lock\n")); /* - * Acquire the global lock semaphore first. - * Since this wait will block, we must release the interpreter + * Wait for handshake with the global lock interrupt handler. + * This interface releases the interpreter if we must wait. */ - status = - acpi_ex_system_wait_semaphore(acpi_gbl_global_lock_semaphore, - timeout); + status = acpi_ex_system_wait_semaphore(acpi_gbl_global_lock_semaphore, + ACPI_WAIT_FOREVER); + return_ACPI_STATUS(status); } @@ -478,38 +499,39 @@ acpi_status acpi_ev_release_global_lock(void) ACPI_FUNCTION_TRACE(ev_release_global_lock); - if (!acpi_gbl_global_lock_thread_count) { + /* Lock must be already acquired */ + + if (!acpi_gbl_global_lock_acquired) { ACPI_WARNING((AE_INFO, - "Cannot release HW Global Lock, it has not been acquired")); + "Cannot release the ACPI Global Lock, it has not been acquired")); return_ACPI_STATUS(AE_NOT_ACQUIRED); } - /* One fewer thread has the global lock */ + if (acpi_gbl_global_lock_present) { - acpi_gbl_global_lock_thread_count--; - if (acpi_gbl_global_lock_thread_count) { + /* Allow any thread to release the lock */ - /* There are still some threads holding the lock, cannot release */ + ACPI_RELEASE_GLOBAL_LOCK(facs, pending); - return_ACPI_STATUS(AE_OK); + /* + * If the pending bit was set, we must write GBL_RLS to the control + * register + */ + if (pending) { + status = + acpi_set_register(ACPI_BITREG_GLOBAL_LOCK_RELEASE, + 1); + } + + ACPI_DEBUG_PRINT((ACPI_DB_EXEC, + "Released hardware Global Lock\n")); } - /* - * No more threads holding lock, we can do the actual hardware - * release - */ - ACPI_RELEASE_GLOBAL_LOCK(acpi_gbl_common_fACS.global_lock, pending); acpi_gbl_global_lock_acquired = FALSE; - /* - * If the pending bit was set, we must write GBL_RLS to the control - * register - */ - if (pending) { - status = acpi_set_register(ACPI_BITREG_GLOBAL_LOCK_RELEASE, - 1, ACPI_MTX_LOCK); - } + /* Release the local GL mutex */ + acpi_os_release_mutex(acpi_gbl_global_lock_mutex); return_ACPI_STATUS(status); } @@ -559,6 +581,12 @@ void acpi_ev_terminate(void) if (ACPI_FAILURE(status)) { ACPI_ERROR((AE_INFO, "Could not remove SCI handler")); } + + status = acpi_ev_remove_global_lock_handler(); + if (ACPI_FAILURE(status)) { + ACPI_ERROR((AE_INFO, + "Could not remove Global Lock handler")); + } } /* Deallocate all handler objects installed within GPE info structs */ |