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+/******************************************************************************
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+ *
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+ * Module Name: evglock - Global Lock support
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+ *
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+ *****************************************************************************/
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+
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+/*
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+ * Copyright (C) 2000 - 2011, Intel Corp.
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+ * All rights reserved.
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+ *
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+ * Redistribution and use in source and binary forms, with or without
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+ * modification, are permitted provided that the following conditions
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+ * are met:
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+ * 1. Redistributions of source code must retain the above copyright
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+ * notice, this list of conditions, and the following disclaimer,
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+ * without modification.
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+ * 2. Redistributions in binary form must reproduce at minimum a disclaimer
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+ * substantially similar to the "NO WARRANTY" disclaimer below
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+ * ("Disclaimer") and any redistribution must be conditioned upon
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+ * including a substantially similar Disclaimer requirement for further
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+ * binary redistribution.
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+ * 3. Neither the names of the above-listed copyright holders nor the names
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+ * of any contributors may be used to endorse or promote products derived
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+ * from this software without specific prior written permission.
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+ *
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+ * Alternatively, this software may be distributed under the terms of the
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+ * GNU General Public License ("GPL") version 2 as published by the Free
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+ * Software Foundation.
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+ *
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+ * NO WARRANTY
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+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
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+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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+ * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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+ * POSSIBILITY OF SUCH DAMAGES.
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+ */
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+
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+#include <acpi/acpi.h>
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+#include "accommon.h"
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+#include "acevents.h"
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+#include "acinterp.h"
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+
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+#define _COMPONENT ACPI_EVENTS
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+ACPI_MODULE_NAME("evglock")
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+
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+/* Local prototypes */
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+static u32 acpi_ev_global_lock_handler(void *context);
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+
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+/*******************************************************************************
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+ *
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+ * FUNCTION: acpi_ev_init_global_lock_handler
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+ *
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+ * PARAMETERS: None
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+ *
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+ * RETURN: Status
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+ *
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+ * DESCRIPTION: Install a handler for the global lock release event
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+ *
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+ ******************************************************************************/
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+
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+acpi_status acpi_ev_init_global_lock_handler(void)
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+{
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+ acpi_status status;
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+
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+ ACPI_FUNCTION_TRACE(ev_init_global_lock_handler);
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+
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+ /* Attempt installation of the global lock handler */
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+
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+ status = acpi_install_fixed_event_handler(ACPI_EVENT_GLOBAL,
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+ acpi_ev_global_lock_handler,
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+ NULL);
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+
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+ /*
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+ * If the global lock does not exist on this platform, the attempt to
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+ * enable GBL_STATUS will fail (the GBL_ENABLE bit will not stick).
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+ * Map to AE_OK, but mark global lock as not present. Any attempt to
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+ * actually use the global lock will be flagged with an error.
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+ */
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+ acpi_gbl_global_lock_present = FALSE;
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+ if (status == AE_NO_HARDWARE_RESPONSE) {
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+ ACPI_ERROR((AE_INFO,
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+ "No response from Global Lock hardware, disabling lock"));
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+
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+ return_ACPI_STATUS(AE_OK);
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+ }
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+
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+ status = acpi_os_create_lock(&acpi_gbl_global_lock_pending_lock);
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+ if (ACPI_FAILURE(status)) {
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+ return_ACPI_STATUS(status);
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+ }
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+
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+ acpi_gbl_global_lock_pending = FALSE;
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+ acpi_gbl_global_lock_present = TRUE;
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+ return_ACPI_STATUS(status);
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+}
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+
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+/*******************************************************************************
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+ *
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+ * FUNCTION: acpi_ev_remove_global_lock_handler
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+ *
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+ * PARAMETERS: None
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+ *
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+ * RETURN: Status
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+ *
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+ * DESCRIPTION: Remove the handler for the Global Lock
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+ *
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+ ******************************************************************************/
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+
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+acpi_status acpi_ev_remove_global_lock_handler(void)
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+{
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+ acpi_status status;
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+
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+ ACPI_FUNCTION_TRACE(ev_remove_global_lock_handler);
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+
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+ acpi_gbl_global_lock_present = FALSE;
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+ status = acpi_remove_fixed_event_handler(ACPI_EVENT_GLOBAL,
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+ acpi_ev_global_lock_handler);
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+
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+ return_ACPI_STATUS(status);
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+}
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+
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+/*******************************************************************************
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+ *
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+ * FUNCTION: acpi_ev_global_lock_handler
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+ *
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+ * PARAMETERS: Context - From thread interface, not used
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+ *
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+ * RETURN: ACPI_INTERRUPT_HANDLED
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+ *
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+ * DESCRIPTION: Invoked directly from the SCI handler when a global lock
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+ * release interrupt occurs. If there is actually a pending
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+ * request for the lock, signal the waiting thread.
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+ *
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+ ******************************************************************************/
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+
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+static u32 acpi_ev_global_lock_handler(void *context)
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+{
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+ acpi_status status;
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+ acpi_cpu_flags flags;
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+
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+ flags = acpi_os_acquire_lock(acpi_gbl_global_lock_pending_lock);
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+
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+ /*
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+ * If a request for the global lock is not actually pending,
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+ * we are done. This handles "spurious" global lock interrupts
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+ * which are possible (and have been seen) with bad BIOSs.
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+ */
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+ if (!acpi_gbl_global_lock_pending) {
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+ goto cleanup_and_exit;
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+ }
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+
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+ /*
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+ * Send a unit to the global lock semaphore. The actual acquisition
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+ * of the global lock will be performed by the waiting thread.
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+ */
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+ status = acpi_os_signal_semaphore(acpi_gbl_global_lock_semaphore, 1);
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+ if (ACPI_FAILURE(status)) {
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+ ACPI_ERROR((AE_INFO, "Could not signal Global Lock semaphore"));
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+ }
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+
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+ acpi_gbl_global_lock_pending = FALSE;
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+
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+ cleanup_and_exit:
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+
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+ acpi_os_release_lock(acpi_gbl_global_lock_pending_lock, flags);
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+ return (ACPI_INTERRUPT_HANDLED);
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+}
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+
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+/******************************************************************************
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+ *
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+ * FUNCTION: acpi_ev_acquire_global_lock
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+ *
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+ * PARAMETERS: Timeout - Max time to wait for the lock, in millisec.
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+ *
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+ * RETURN: Status
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+ *
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+ * DESCRIPTION: Attempt to gain ownership of the Global Lock.
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+ *
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+ * MUTEX: Interpreter must be locked
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+ *
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+ * Note: The original implementation allowed multiple threads to "acquire" the
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+ * Global Lock, and the OS would hold the lock until the last thread had
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+ * released it. However, this could potentially starve the BIOS out of the
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+ * lock, especially in the case where there is a tight handshake between the
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+ * Embedded Controller driver and the BIOS. Therefore, this implementation
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+ * allows only one thread to acquire the HW Global Lock at a time, and makes
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+ * the global lock appear as a standard mutex on the OS side.
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+ *
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+ *****************************************************************************/
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+
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+acpi_status acpi_ev_acquire_global_lock(u16 timeout)
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+{
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+ acpi_cpu_flags flags;
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+ acpi_status status;
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+ u8 acquired = FALSE;
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+
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+ ACPI_FUNCTION_TRACE(ev_acquire_global_lock);
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+
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+ /*
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+ * Only one thread can acquire the GL at a time, the global_lock_mutex
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+ * enforces this. This interface releases the interpreter if we must wait.
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+ */
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+ status =
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+ acpi_ex_system_wait_mutex(acpi_gbl_global_lock_mutex->mutex.
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+ os_mutex, timeout);
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+ if (ACPI_FAILURE(status)) {
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+ return_ACPI_STATUS(status);
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+ }
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+
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+ /*
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+ * Update the global lock handle and check for wraparound. The handle is
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+ * only used for the external global lock interfaces, but it is updated
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+ * here to properly handle the case where a single thread may acquire the
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+ * lock via both the AML and the acpi_acquire_global_lock interfaces. The
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+ * handle is therefore updated on the first acquire from a given thread
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+ * regardless of where the acquisition request originated.
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+ */
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+ acpi_gbl_global_lock_handle++;
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+ if (acpi_gbl_global_lock_handle == 0) {
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+ acpi_gbl_global_lock_handle = 1;
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+ }
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+
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+ /*
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+ * Make sure that a global lock actually exists. If not, just
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+ * treat the lock as a standard mutex.
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+ */
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+ if (!acpi_gbl_global_lock_present) {
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+ acpi_gbl_global_lock_acquired = TRUE;
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+ return_ACPI_STATUS(AE_OK);
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+ }
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+
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+ flags = acpi_os_acquire_lock(acpi_gbl_global_lock_pending_lock);
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+
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+ do {
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+
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+ /* Attempt to acquire the actual hardware lock */
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+
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+ ACPI_ACQUIRE_GLOBAL_LOCK(acpi_gbl_FACS, acquired);
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+ if (acquired) {
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+ acpi_gbl_global_lock_acquired = TRUE;
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+ ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
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+ "Acquired hardware Global Lock\n"));
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+ break;
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+ }
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+
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+ /*
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+ * Did not get the lock. The pending bit was set above, and
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+ * we must now wait until we receive the global lock
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+ * released interrupt.
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+ */
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+ acpi_gbl_global_lock_pending = TRUE;
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+ acpi_os_release_lock(acpi_gbl_global_lock_pending_lock, flags);
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+
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+ ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
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+ "Waiting for hardware Global Lock\n"));
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+
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+ /*
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+ * Wait for handshake with the global lock interrupt handler.
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+ * This interface releases the interpreter if we must wait.
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+ */
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+ status =
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+ acpi_ex_system_wait_semaphore
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+ (acpi_gbl_global_lock_semaphore, ACPI_WAIT_FOREVER);
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+
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+ flags = acpi_os_acquire_lock(acpi_gbl_global_lock_pending_lock);
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+
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+ } while (ACPI_SUCCESS(status));
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+
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+ acpi_gbl_global_lock_pending = FALSE;
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+ acpi_os_release_lock(acpi_gbl_global_lock_pending_lock, flags);
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+
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+ return_ACPI_STATUS(status);
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+}
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+
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+/*******************************************************************************
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+ *
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+ * FUNCTION: acpi_ev_release_global_lock
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+ *
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+ * PARAMETERS: None
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+ *
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+ * RETURN: Status
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+ *
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+ * DESCRIPTION: Releases ownership of the Global Lock.
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+ *
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+ ******************************************************************************/
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+
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+acpi_status acpi_ev_release_global_lock(void)
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+{
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+ u8 pending = FALSE;
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+ acpi_status status = AE_OK;
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+
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+ ACPI_FUNCTION_TRACE(ev_release_global_lock);
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+
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+ /* Lock must be already acquired */
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+
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+ if (!acpi_gbl_global_lock_acquired) {
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+ ACPI_WARNING((AE_INFO,
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+ "Cannot release the ACPI Global Lock, it has not been acquired"));
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+ return_ACPI_STATUS(AE_NOT_ACQUIRED);
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+ }
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+
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+ if (acpi_gbl_global_lock_present) {
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+
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+ /* Allow any thread to release the lock */
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+
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+ ACPI_RELEASE_GLOBAL_LOCK(acpi_gbl_FACS, pending);
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+
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+ /*
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+ * If the pending bit was set, we must write GBL_RLS to the control
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+ * register
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+ */
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+ if (pending) {
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+ status =
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+ acpi_write_bit_register
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+ (ACPI_BITREG_GLOBAL_LOCK_RELEASE,
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+ ACPI_ENABLE_EVENT);
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+ }
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+
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+ ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
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+ "Released hardware Global Lock\n"));
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+ }
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+
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+ acpi_gbl_global_lock_acquired = FALSE;
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+
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+ /* Release the local GL mutex */
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+
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+ acpi_os_release_mutex(acpi_gbl_global_lock_mutex->mutex.os_mutex);
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+ return_ACPI_STATUS(status);
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+}
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