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Diffstat (limited to 'drivers/acpi/acpica/evglock.c')
-rw-r--r--drivers/acpi/acpica/evglock.c335
1 files changed, 335 insertions, 0 deletions
diff --git a/drivers/acpi/acpica/evglock.c b/drivers/acpi/acpica/evglock.c
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index 000000000000..56a562a1e5d7
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+++ b/drivers/acpi/acpica/evglock.c
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+/******************************************************************************
+ *
+ * Module Name: evglock - Global Lock support
+ *
+ *****************************************************************************/
+
+/*
+ * Copyright (C) 2000 - 2011, Intel Corp.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions, and the following disclaimer,
+ * without modification.
+ * 2. Redistributions in binary form must reproduce at minimum a disclaimer
+ * substantially similar to the "NO WARRANTY" disclaimer below
+ * ("Disclaimer") and any redistribution must be conditioned upon
+ * including a substantially similar Disclaimer requirement for further
+ * binary redistribution.
+ * 3. Neither the names of the above-listed copyright holders nor the names
+ * of any contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * Alternatively, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") version 2 as published by the Free
+ * Software Foundation.
+ *
+ * NO WARRANTY
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGES.
+ */
+
+#include <acpi/acpi.h>
+#include "accommon.h"
+#include "acevents.h"
+#include "acinterp.h"
+
+#define _COMPONENT ACPI_EVENTS
+ACPI_MODULE_NAME("evglock")
+
+/* Local prototypes */
+static u32 acpi_ev_global_lock_handler(void *context);
+
+/*******************************************************************************
+ *
+ * FUNCTION: acpi_ev_init_global_lock_handler
+ *
+ * PARAMETERS: None
+ *
+ * RETURN: Status
+ *
+ * DESCRIPTION: Install a handler for the global lock release event
+ *
+ ******************************************************************************/
+
+acpi_status acpi_ev_init_global_lock_handler(void)
+{
+ acpi_status status;
+
+ ACPI_FUNCTION_TRACE(ev_init_global_lock_handler);
+
+ /* Attempt installation of the global lock handler */
+
+ status = acpi_install_fixed_event_handler(ACPI_EVENT_GLOBAL,
+ acpi_ev_global_lock_handler,
+ NULL);
+
+ /*
+ * If the global lock does not exist on this platform, the attempt to
+ * enable GBL_STATUS will fail (the GBL_ENABLE bit will not stick).
+ * Map to AE_OK, but mark global lock as not present. Any attempt to
+ * actually use the global lock will be flagged with an error.
+ */
+ acpi_gbl_global_lock_present = FALSE;
+ if (status == AE_NO_HARDWARE_RESPONSE) {
+ ACPI_ERROR((AE_INFO,
+ "No response from Global Lock hardware, disabling lock"));
+
+ return_ACPI_STATUS(AE_OK);
+ }
+
+ status = acpi_os_create_lock(&acpi_gbl_global_lock_pending_lock);
+ if (ACPI_FAILURE(status)) {
+ return_ACPI_STATUS(status);
+ }
+
+ acpi_gbl_global_lock_pending = FALSE;
+ acpi_gbl_global_lock_present = TRUE;
+ return_ACPI_STATUS(status);
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION: acpi_ev_remove_global_lock_handler
+ *
+ * PARAMETERS: None
+ *
+ * RETURN: Status
+ *
+ * DESCRIPTION: Remove the handler for the Global Lock
+ *
+ ******************************************************************************/
+
+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_global_lock_handler
+ *
+ * PARAMETERS: Context - From thread interface, not used
+ *
+ * RETURN: ACPI_INTERRUPT_HANDLED
+ *
+ * DESCRIPTION: Invoked directly from the SCI handler when a global lock
+ * release interrupt occurs. If there is actually a pending
+ * request for the lock, signal the waiting thread.
+ *
+ ******************************************************************************/
+
+static u32 acpi_ev_global_lock_handler(void *context)
+{
+ acpi_status status;
+ acpi_cpu_flags flags;
+
+ flags = acpi_os_acquire_lock(acpi_gbl_global_lock_pending_lock);
+
+ /*
+ * If a request for the global lock is not actually pending,
+ * we are done. This handles "spurious" global lock interrupts
+ * which are possible (and have been seen) with bad BIOSs.
+ */
+ if (!acpi_gbl_global_lock_pending) {
+ goto cleanup_and_exit;
+ }
+
+ /*
+ * Send a unit to the global lock semaphore. The actual acquisition
+ * of the global lock will be performed by the waiting thread.
+ */
+ status = acpi_os_signal_semaphore(acpi_gbl_global_lock_semaphore, 1);
+ if (ACPI_FAILURE(status)) {
+ ACPI_ERROR((AE_INFO, "Could not signal Global Lock semaphore"));
+ }
+
+ acpi_gbl_global_lock_pending = FALSE;
+
+ cleanup_and_exit:
+
+ acpi_os_release_lock(acpi_gbl_global_lock_pending_lock, flags);
+ return (ACPI_INTERRUPT_HANDLED);
+}
+
+/******************************************************************************
+ *
+ * FUNCTION: acpi_ev_acquire_global_lock
+ *
+ * PARAMETERS: Timeout - Max time to wait for the lock, in millisec.
+ *
+ * RETURN: Status
+ *
+ * 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)
+{
+ acpi_cpu_flags flags;
+ acpi_status status;
+ u8 acquired = FALSE;
+
+ ACPI_FUNCTION_TRACE(ev_acquire_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->mutex.
+ os_mutex, timeout);
+ if (ACPI_FAILURE(status)) {
+ return_ACPI_STATUS(status);
+ }
+
+ /*
+ * Update the global lock handle and check for wraparound. The handle is
+ * only used for the external global lock interfaces, but it is updated
+ * here to properly handle the case where a single thread may acquire the
+ * lock via both the AML and the acpi_acquire_global_lock interfaces. The
+ * handle is therefore updated on the first acquire from a given thread
+ * regardless of where the acquisition request originated.
+ */
+ acpi_gbl_global_lock_handle++;
+ if (acpi_gbl_global_lock_handle == 0) {
+ acpi_gbl_global_lock_handle = 1;
+ }
+
+ /*
+ * Make sure that a global lock actually exists. If not, just
+ * treat the lock as a standard mutex.
+ */
+ if (!acpi_gbl_global_lock_present) {
+ acpi_gbl_global_lock_acquired = TRUE;
+ return_ACPI_STATUS(AE_OK);
+ }
+
+ flags = acpi_os_acquire_lock(acpi_gbl_global_lock_pending_lock);
+
+ do {
+
+ /* Attempt to acquire the actual hardware lock */
+
+ ACPI_ACQUIRE_GLOBAL_LOCK(acpi_gbl_FACS, acquired);
+ if (acquired) {
+ acpi_gbl_global_lock_acquired = TRUE;
+ ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
+ "Acquired hardware Global Lock\n"));
+ break;
+ }
+
+ /*
+ * Did not get the lock. The pending bit was set above, and
+ * we must now wait until we receive the global lock
+ * released interrupt.
+ */
+ acpi_gbl_global_lock_pending = TRUE;
+ acpi_os_release_lock(acpi_gbl_global_lock_pending_lock, flags);
+
+ ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
+ "Waiting for hardware Global Lock\n"));
+
+ /*
+ * 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, ACPI_WAIT_FOREVER);
+
+ flags = acpi_os_acquire_lock(acpi_gbl_global_lock_pending_lock);
+
+ } while (ACPI_SUCCESS(status));
+
+ acpi_gbl_global_lock_pending = FALSE;
+ acpi_os_release_lock(acpi_gbl_global_lock_pending_lock, flags);
+
+ return_ACPI_STATUS(status);
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION: acpi_ev_release_global_lock
+ *
+ * PARAMETERS: None
+ *
+ * RETURN: Status
+ *
+ * DESCRIPTION: Releases ownership of the Global Lock.
+ *
+ ******************************************************************************/
+
+acpi_status acpi_ev_release_global_lock(void)
+{
+ u8 pending = FALSE;
+ acpi_status status = AE_OK;
+
+ ACPI_FUNCTION_TRACE(ev_release_global_lock);
+
+ /* Lock must be already acquired */
+
+ if (!acpi_gbl_global_lock_acquired) {
+ ACPI_WARNING((AE_INFO,
+ "Cannot release the ACPI Global Lock, it has not been acquired"));
+ return_ACPI_STATUS(AE_NOT_ACQUIRED);
+ }
+
+ if (acpi_gbl_global_lock_present) {
+
+ /* Allow any thread to release the lock */
+
+ ACPI_RELEASE_GLOBAL_LOCK(acpi_gbl_FACS, pending);
+
+ /*
+ * If the pending bit was set, we must write GBL_RLS to the control
+ * register
+ */
+ if (pending) {
+ status =
+ acpi_write_bit_register
+ (ACPI_BITREG_GLOBAL_LOCK_RELEASE,
+ ACPI_ENABLE_EVENT);
+ }
+
+ ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
+ "Released hardware Global Lock\n"));
+ }
+
+ acpi_gbl_global_lock_acquired = FALSE;
+
+ /* Release the local GL mutex */
+
+ acpi_os_release_mutex(acpi_gbl_global_lock_mutex->mutex.os_mutex);
+ return_ACPI_STATUS(status);
+}