FreeBSD/Linux Kernel Cross Reference
sys/contrib/dev/acpica/components/events/evhandler.c

     /******************************************************************************
      *
      * Module Name: evhandler - Support for Address Space handlers
      *
      *****************************************************************************/
     
     /******************************************************************************
      *
      * 1. Copyright Notice
     *
     * Some or all of this work - Copyright (c) 1999 - 2022, Intel Corp.
     * All rights reserved.
     *
     * 2. License
     *
     * 2.1. This is your license from Intel Corp. under its intellectual property
     * rights. You may have additional license terms from the party that provided
     * you this software, covering your right to use that party's intellectual
     * property rights.
     *
     * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a
     * copy of the source code appearing in this file ("Covered Code") an
     * irrevocable, perpetual, worldwide license under Intel's copyrights in the
     * base code distributed originally by Intel ("Original Intel Code") to copy,
     * make derivatives, distribute, use and display any portion of the Covered
     * Code in any form, with the right to sublicense such rights; and
     *
     * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent
     * license (with the right to sublicense), under only those claims of Intel
     * patents that are infringed by the Original Intel Code, to make, use, sell,
     * offer to sell, and import the Covered Code and derivative works thereof
     * solely to the minimum extent necessary to exercise the above copyright
     * license, and in no event shall the patent license extend to any additions
     * to or modifications of the Original Intel Code. No other license or right
     * is granted directly or by implication, estoppel or otherwise;
     *
     * The above copyright and patent license is granted only if the following
     * conditions are met:
     *
     * 3. Conditions
     *
     * 3.1. Redistribution of Source with Rights to Further Distribute Source.
     * Redistribution of source code of any substantial portion of the Covered
     * Code or modification with rights to further distribute source must include
     * the above Copyright Notice, the above License, this list of Conditions,
     * and the following Disclaimer and Export Compliance provision. In addition,
     * Licensee must cause all Covered Code to which Licensee contributes to
     * contain a file documenting the changes Licensee made to create that Covered
     * Code and the date of any change. Licensee must include in that file the
     * documentation of any changes made by any predecessor Licensee. Licensee
     * must include a prominent statement that the modification is derived,
     * directly or indirectly, from Original Intel Code.
     *
     * 3.2. Redistribution of Source with no Rights to Further Distribute Source.
     * Redistribution of source code of any substantial portion of the Covered
     * Code or modification without rights to further distribute source must
     * include the following Disclaimer and Export Compliance provision in the
     * documentation and/or other materials provided with distribution. In
     * addition, Licensee may not authorize further sublicense of source of any
     * portion of the Covered Code, and must include terms to the effect that the
     * license from Licensee to its licensee is limited to the intellectual
     * property embodied in the software Licensee provides to its licensee, and
     * not to intellectual property embodied in modifications its licensee may
     * make.
     *
     * 3.3. Redistribution of Executable. Redistribution in executable form of any
     * substantial portion of the Covered Code or modification must reproduce the
     * above Copyright Notice, and the following Disclaimer and Export Compliance
     * provision in the documentation and/or other materials provided with the
     * distribution.
     *
     * 3.4. Intel retains all right, title, and interest in and to the Original
     * Intel Code.
     *
     * 3.5. Neither the name Intel nor any other trademark owned or controlled by
     * Intel shall be used in advertising or otherwise to promote the sale, use or
     * other dealings in products derived from or relating to the Covered Code
     * without prior written authorization from Intel.
     *
     * 4. Disclaimer and Export Compliance
     *
     * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED
     * HERE. ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE
     * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT, ASSISTANCE,
     * INSTALLATION, TRAINING OR OTHER SERVICES. INTEL WILL NOT PROVIDE ANY
     * UPDATES, ENHANCEMENTS OR EXTENSIONS. INTEL SPECIFICALLY DISCLAIMS ANY
     * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A
     * PARTICULAR PURPOSE.
     *
     * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES
     * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR
     * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT,
     * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY
     * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL
     * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES. THESE LIMITATIONS
     * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY
     * LIMITED REMEDY.
     *
     * 4.3. Licensee shall not export, either directly or indirectly, any of this
    * software or system incorporating such software without first obtaining any
    * required license or other approval from the U. S. Department of Commerce or
    * any other agency or department of the United States Government. In the
    * event Licensee exports any such software from the United States or
    * re-exports any such software from a foreign destination, Licensee shall
    * ensure that the distribution and export/re-export of the software is in
    * compliance with all laws, regulations, orders, or other restrictions of the
    * U.S. Export Administration Regulations. Licensee agrees that neither it nor
    * any of its subsidiaries will export/re-export any technical data, process,
    * software, or service, directly or indirectly, to any country for which the
    * United States government or any agency thereof requires an export license,
    * other governmental approval, or letter of assurance, without first obtaining
    * such license, approval or letter.
    *
    *****************************************************************************
    *
    * Alternatively, you may choose to be licensed under the terms of the
    * following license:
    *
    * 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.
    *
    * 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 MERCHANTABILITY AND FITNESS FOR
    * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
    * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    * 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 DAMAGE.
    *
    * Alternatively, you may choose to be licensed under the terms of the
    * GNU General Public License ("GPL") version 2 as published by the Free
    * Software Foundation.
    *
    *****************************************************************************/
   
   #include <contrib/dev/acpica/include/acpi.h>
   #include <contrib/dev/acpica/include/accommon.h>
   #include <contrib/dev/acpica/include/acevents.h>
   #include <contrib/dev/acpica/include/acnamesp.h>
   #include <contrib/dev/acpica/include/acinterp.h>
   
   #define _COMPONENT          ACPI_EVENTS
           ACPI_MODULE_NAME    ("evhandler")
   
   
   /* Local prototypes */
   
   static ACPI_STATUS
   AcpiEvInstallHandler (
       ACPI_HANDLE             ObjHandle,
       UINT32                  Level,
       void                    *Context,
       void                    **ReturnValue);
   
   
   /* These are the address spaces that will get default handlers */
   
   UINT8        AcpiGbl_DefaultAddressSpaces[ACPI_NUM_DEFAULT_SPACES] =
   {
       ACPI_ADR_SPACE_SYSTEM_MEMORY,
       ACPI_ADR_SPACE_SYSTEM_IO,
       ACPI_ADR_SPACE_PCI_CONFIG,
       ACPI_ADR_SPACE_DATA_TABLE
   };
   
   
   /*******************************************************************************
    *
    * FUNCTION:    AcpiEvInstallRegionHandlers
    *
    * PARAMETERS:  None
    *
    * RETURN:      Status
    *
    * DESCRIPTION: Installs the core subsystem default address space handlers.
    *
    ******************************************************************************/
   
   ACPI_STATUS
   AcpiEvInstallRegionHandlers (
       void)
   {
       ACPI_STATUS             Status;
       UINT32                  i;
   
   
       ACPI_FUNCTION_TRACE (EvInstallRegionHandlers);
   
   
       Status = AcpiUtAcquireMutex (ACPI_MTX_NAMESPACE);
       if (ACPI_FAILURE (Status))
       {
           return_ACPI_STATUS (Status);
       }
   
       /*
        * All address spaces (PCI Config, EC, SMBus) are scope dependent and
        * registration must occur for a specific device.
        *
        * In the case of the system memory and IO address spaces there is
        * currently no device associated with the address space. For these we
        * use the root.
        *
        * We install the default PCI config space handler at the root so that
        * this space is immediately available even though the we have not
        * enumerated all the PCI Root Buses yet. This is to conform to the ACPI
        * specification which states that the PCI config space must be always
        * available -- even though we are nowhere near ready to find the PCI root
        * buses at this point.
        *
        * NOTE: We ignore AE_ALREADY_EXISTS because this means that a handler
        * has already been installed (via AcpiInstallAddressSpaceHandler).
        * Similar for AE_SAME_HANDLER.
        */
       for (i = 0; i < ACPI_NUM_DEFAULT_SPACES; i++)
       {
           Status = AcpiEvInstallSpaceHandler (AcpiGbl_RootNode,
               AcpiGbl_DefaultAddressSpaces[i],
               ACPI_DEFAULT_HANDLER, NULL, NULL);
           switch (Status)
           {
           case AE_OK:
           case AE_SAME_HANDLER:
           case AE_ALREADY_EXISTS:
   
               /* These exceptions are all OK */
   
               Status = AE_OK;
               break;
   
           default:
   
               goto UnlockAndExit;
           }
       }
   
   UnlockAndExit:
       (void) AcpiUtReleaseMutex (ACPI_MTX_NAMESPACE);
       return_ACPI_STATUS (Status);
   }
   
   
   /*******************************************************************************
    *
    * FUNCTION:    AcpiEvHasDefaultHandler
    *
    * PARAMETERS:  Node                - Namespace node for the device
    *              SpaceId             - The address space ID
    *
    * RETURN:      TRUE if default handler is installed, FALSE otherwise
    *
    * DESCRIPTION: Check if the default handler is installed for the requested
    *              space ID.
    *
    ******************************************************************************/
   
   BOOLEAN
   AcpiEvHasDefaultHandler (
       ACPI_NAMESPACE_NODE     *Node,
       ACPI_ADR_SPACE_TYPE     SpaceId)
   {
       ACPI_OPERAND_OBJECT     *ObjDesc;
       ACPI_OPERAND_OBJECT     *HandlerObj;
   
   
       /* Must have an existing internal object */
   
       ObjDesc = AcpiNsGetAttachedObject (Node);
       if (ObjDesc)
       {
           HandlerObj = ObjDesc->CommonNotify.Handler;
   
           /* Walk the linked list of handlers for this object */
   
           while (HandlerObj)
           {
               if (HandlerObj->AddressSpace.SpaceId == SpaceId)
               {
                   if (HandlerObj->AddressSpace.HandlerFlags &
                       ACPI_ADDR_HANDLER_DEFAULT_INSTALLED)
                   {
                       return (TRUE);
                   }
               }
   
               HandlerObj = HandlerObj->AddressSpace.Next;
           }
       }
   
       return (FALSE);
   }
   
   
   /*******************************************************************************
    *
    * FUNCTION:    AcpiEvInstallHandler
    *
    * PARAMETERS:  WalkNamespace callback
    *
    * DESCRIPTION: This routine installs an address handler into objects that are
    *              of type Region or Device.
    *
    *              If the Object is a Device, and the device has a handler of
    *              the same type then the search is terminated in that branch.
    *
    *              This is because the existing handler is closer in proximity
    *              to any more regions than the one we are trying to install.
    *
    ******************************************************************************/
   
   static ACPI_STATUS
   AcpiEvInstallHandler (
       ACPI_HANDLE             ObjHandle,
       UINT32                  Level,
       void                    *Context,
       void                    **ReturnValue)
   {
       ACPI_OPERAND_OBJECT     *HandlerObj;
       ACPI_OPERAND_OBJECT     *NextHandlerObj;
       ACPI_OPERAND_OBJECT     *ObjDesc;
       ACPI_NAMESPACE_NODE     *Node;
       ACPI_STATUS             Status;
   
   
       ACPI_FUNCTION_NAME (EvInstallHandler);
   
   
       HandlerObj = (ACPI_OPERAND_OBJECT  *) Context;
   
       /* Parameter validation */
   
       if (!HandlerObj)
       {
           return (AE_OK);
       }
   
       /* Convert and validate the device handle */
   
       Node = AcpiNsValidateHandle (ObjHandle);
       if (!Node)
       {
           return (AE_BAD_PARAMETER);
       }
   
       /*
        * We only care about regions and objects that are allowed to have
        * address space handlers
        */
       if ((Node->Type != ACPI_TYPE_DEVICE) &&
           (Node->Type != ACPI_TYPE_REGION) &&
           (Node != AcpiGbl_RootNode))
       {
           return (AE_OK);
       }
   
       /* Check for an existing internal object */
   
       ObjDesc = AcpiNsGetAttachedObject (Node);
       if (!ObjDesc)
       {
           /* No object, just exit */
   
           return (AE_OK);
       }
   
       /* Devices are handled different than regions */
   
       if (ObjDesc->Common.Type == ACPI_TYPE_DEVICE)
       {
           /* Check if this Device already has a handler for this address space */
   
           NextHandlerObj = AcpiEvFindRegionHandler (
               HandlerObj->AddressSpace.SpaceId, ObjDesc->CommonNotify.Handler);
           if (NextHandlerObj)
           {
               /* Found a handler, is it for the same address space? */
   
               ACPI_DEBUG_PRINT ((ACPI_DB_OPREGION,
                   "Found handler for region [%s] in device %p(%p) handler %p\n",
                   AcpiUtGetRegionName (HandlerObj->AddressSpace.SpaceId),
                   ObjDesc, NextHandlerObj, HandlerObj));
   
               /*
                * Since the object we found it on was a device, then it means
                * that someone has already installed a handler for the branch
                * of the namespace from this device on. Just bail out telling
                * the walk routine to not traverse this branch. This preserves
                * the scoping rule for handlers.
                */
               return (AE_CTRL_DEPTH);
           }
   
           /*
            * As long as the device didn't have a handler for this space we
            * don't care about it. We just ignore it and proceed.
            */
           return (AE_OK);
       }
   
       /* Object is a Region */
   
       if (ObjDesc->Region.SpaceId != HandlerObj->AddressSpace.SpaceId)
       {
           /* This region is for a different address space, just ignore it */
   
           return (AE_OK);
       }
   
       /*
        * Now we have a region and it is for the handler's address space type.
        *
        * First disconnect region for any previous handler (if any)
        */
       AcpiEvDetachRegion (ObjDesc, FALSE);
   
       /* Connect the region to the new handler */
   
       Status = AcpiEvAttachRegion (HandlerObj, ObjDesc, FALSE);
       return (Status);
   }
   
   
   /*******************************************************************************
    *
    * FUNCTION:    AcpiEvFindRegionHandler
    *
    * PARAMETERS:  SpaceId         - The address space ID
    *              HandlerObj      - Head of the handler object list
    *
    * RETURN:      Matching handler object. NULL if space ID not matched
    *
    * DESCRIPTION: Search a handler object list for a match on the address
    *              space ID.
    *
    ******************************************************************************/
   
   ACPI_OPERAND_OBJECT *
   AcpiEvFindRegionHandler (
       ACPI_ADR_SPACE_TYPE     SpaceId,
       ACPI_OPERAND_OBJECT     *HandlerObj)
   {
   
       /* Walk the handler list for this device */
   
       while (HandlerObj)
       {
           /* Same SpaceId indicates a handler is installed */
   
           if (HandlerObj->AddressSpace.SpaceId == SpaceId)
           {
               return (HandlerObj);
           }
   
           /* Next handler object */
   
           HandlerObj = HandlerObj->AddressSpace.Next;
       }
   
       return (NULL);
   }
   
   
   /*******************************************************************************
    *
    * FUNCTION:    AcpiEvInstallSpaceHandler
    *
    * PARAMETERS:  Node            - Namespace node for the device
    *              SpaceId         - The address space ID
    *              Handler         - Address of the handler
    *              Setup           - Address of the setup function
    *              Context         - Value passed to the handler on each access
    *
    * RETURN:      Status
    *
    * DESCRIPTION: Install a handler for all OpRegions of a given SpaceId.
    *              Assumes namespace is locked
    *
    ******************************************************************************/
   
   ACPI_STATUS
   AcpiEvInstallSpaceHandler (
       ACPI_NAMESPACE_NODE     *Node,
       ACPI_ADR_SPACE_TYPE     SpaceId,
       ACPI_ADR_SPACE_HANDLER  Handler,
       ACPI_ADR_SPACE_SETUP    Setup,
       void                    *Context)
   {
       ACPI_OPERAND_OBJECT     *ObjDesc;
       ACPI_OPERAND_OBJECT     *HandlerObj;
       ACPI_STATUS             Status = AE_OK;
       ACPI_OBJECT_TYPE        Type;
       UINT8                   Flags = 0;
   
   
       ACPI_FUNCTION_TRACE (EvInstallSpaceHandler);
   
   
       /*
        * This registration is valid for only the types below and the root.
        * The root node is where the default handlers get installed.
        */
       if ((Node->Type != ACPI_TYPE_DEVICE)     &&
           (Node->Type != ACPI_TYPE_PROCESSOR)  &&
           (Node->Type != ACPI_TYPE_THERMAL)    &&
           (Node != AcpiGbl_RootNode))
       {
           Status = AE_BAD_PARAMETER;
           goto UnlockAndExit;
       }
   
       if (Handler == ACPI_DEFAULT_HANDLER)
       {
           Flags = ACPI_ADDR_HANDLER_DEFAULT_INSTALLED;
   
           switch (SpaceId)
           {
           case ACPI_ADR_SPACE_SYSTEM_MEMORY:
   
               Handler = AcpiExSystemMemorySpaceHandler;
               Setup   = AcpiEvSystemMemoryRegionSetup;
               break;
   
           case ACPI_ADR_SPACE_SYSTEM_IO:
   
               Handler = AcpiExSystemIoSpaceHandler;
               Setup   = AcpiEvIoSpaceRegionSetup;
               break;
   
           case ACPI_ADR_SPACE_PCI_CONFIG:
   
               Handler = AcpiExPciConfigSpaceHandler;
               Setup   = AcpiEvPciConfigRegionSetup;
               break;
   
           case ACPI_ADR_SPACE_CMOS:
   
               Handler = AcpiExCmosSpaceHandler;
               Setup   = AcpiEvCmosRegionSetup;
               break;
   
           case ACPI_ADR_SPACE_PCI_BAR_TARGET:
   
               Handler = AcpiExPciBarSpaceHandler;
               Setup   = AcpiEvPciBarRegionSetup;
               break;
   
           case ACPI_ADR_SPACE_DATA_TABLE:
   
               Handler = AcpiExDataTableSpaceHandler;
               Setup   = AcpiEvDataTableRegionSetup;
               break;
   
           default:
   
               Status = AE_BAD_PARAMETER;
               goto UnlockAndExit;
           }
       }
   
       /* If the caller hasn't specified a setup routine, use the default */
   
       if (!Setup)
       {
           Setup = AcpiEvDefaultRegionSetup;
       }
   
       /* Check for an existing internal object */
   
       ObjDesc = AcpiNsGetAttachedObject (Node);
       if (ObjDesc)
       {
           /*
            * The attached device object already exists. Now make sure
            * the handler is not already installed.
            */
           HandlerObj = AcpiEvFindRegionHandler (SpaceId,
               ObjDesc->CommonNotify.Handler);
   
           if (HandlerObj)
           {
               if (HandlerObj->AddressSpace.Handler == Handler)
               {
                   /*
                    * It is (relatively) OK to attempt to install the SAME
                    * handler twice. This can easily happen with the
                    * PCI_Config space.
                    */
                   Status = AE_SAME_HANDLER;
                   goto UnlockAndExit;
               }
               else
               {
                   /* A handler is already installed */
   
                   Status = AE_ALREADY_EXISTS;
               }
   
               goto UnlockAndExit;
           }
       }
       else
       {
           ACPI_DEBUG_PRINT ((ACPI_DB_OPREGION,
               "Creating object on Device %p while installing handler\n",
               Node));
   
           /* ObjDesc does not exist, create one */
   
           if (Node->Type == ACPI_TYPE_ANY)
           {
               Type = ACPI_TYPE_DEVICE;
           }
           else
           {
               Type = Node->Type;
           }
   
           ObjDesc = AcpiUtCreateInternalObject (Type);
           if (!ObjDesc)
           {
               Status = AE_NO_MEMORY;
               goto UnlockAndExit;
           }
   
           /* Init new descriptor */
   
           ObjDesc->Common.Type = (UINT8) Type;
   
           /* Attach the new object to the Node */
   
           Status = AcpiNsAttachObject (Node, ObjDesc, Type);
   
           /* Remove local reference to the object */
   
           AcpiUtRemoveReference (ObjDesc);
   
           if (ACPI_FAILURE (Status))
           {
               goto UnlockAndExit;
           }
       }
   
       ACPI_DEBUG_PRINT ((ACPI_DB_OPREGION,
           "Installing address handler for region %s(%X) "
           "on Device %4.4s %p(%p)\n",
           AcpiUtGetRegionName (SpaceId), SpaceId,
           AcpiUtGetNodeName (Node), Node, ObjDesc));
   
       /*
        * Install the handler
        *
        * At this point there is no existing handler. Just allocate the object
        * for the handler and link it into the list.
        */
       HandlerObj = AcpiUtCreateInternalObject (ACPI_TYPE_LOCAL_ADDRESS_HANDLER);
       if (!HandlerObj)
       {
           Status = AE_NO_MEMORY;
           goto UnlockAndExit;
       }
   
       /* Init handler obj */
   
       Status = AcpiOsCreateMutex (&HandlerObj->AddressSpace.ContextMutex);
       if (ACPI_FAILURE (Status))
       {
           AcpiUtRemoveReference (HandlerObj);
           goto UnlockAndExit;
       }
   
       HandlerObj->AddressSpace.SpaceId = (UINT8) SpaceId;
       HandlerObj->AddressSpace.HandlerFlags = Flags;
       HandlerObj->AddressSpace.RegionList = NULL;
       HandlerObj->AddressSpace.Node = Node;
       HandlerObj->AddressSpace.Handler = Handler;
       HandlerObj->AddressSpace.Context = Context;
       HandlerObj->AddressSpace.Setup = Setup;
   
       /* Install at head of Device.AddressSpace list */
   
       HandlerObj->AddressSpace.Next = ObjDesc->CommonNotify.Handler;
   
       /*
        * The Device object is the first reference on the HandlerObj.
        * Each region that uses the handler adds a reference.
        */
       ObjDesc->CommonNotify.Handler = HandlerObj;
   
       /*
        * Walk the namespace finding all of the regions this handler will
        * manage.
        *
        * Start at the device and search the branch toward the leaf nodes
        * until either the leaf is encountered or a device is detected that
        * has an address handler of the same type.
        *
        * In either case, back up and search down the remainder of the branch
        */
       Status = AcpiNsWalkNamespace (ACPI_TYPE_ANY, Node,
           ACPI_UINT32_MAX, ACPI_NS_WALK_UNLOCK,
           AcpiEvInstallHandler, NULL, HandlerObj, NULL);
   
   UnlockAndExit:
       return_ACPI_STATUS (Status);
   }

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