dsmthdat.c

Linux内核源代码 为压缩文件 是<<Linux内核>>一书中的源代码

	}

	/* Get the object from the method stack */

	object = *entry;

	/* Get the object type */

	if (!object) {
		/* Any == 0 => "uninitialized" -- see spec 15.2.3.5.2.28 */
		return (ACPI_TYPE_ANY);
	}

	return (object->common.type);
}


/*******************************************************************************
 *
 * FUNCTION:    Acpi_ds_method_data_get_nte
 *
 * PARAMETERS:  Type                - Either MTH_TYPE_LOCAL or MTH_TYPE_ARG
 *              Index               - Which local_var or argument whose type
 *                                      to get
 *
 * RETURN:      Get the Node associated with a local or arg.
 *
 ******************************************************************************/

ACPI_NAMESPACE_NODE *
acpi_ds_method_data_get_nte (
	u32                     type,
	u32                     index,
	ACPI_WALK_STATE         *walk_state)
{
	ACPI_NAMESPACE_NODE     *node = NULL;


	switch (type)
	{

	case MTH_TYPE_LOCAL:

		if (index > MTH_MAX_LOCAL) {
			return (node);
		}

		node =  &walk_state->local_variables[index];
		break;


	case MTH_TYPE_ARG:

		if (index > MTH_MAX_ARG) {
			return (node);
		}

		node = &walk_state->arguments[index];
		break;


	default:
		break;
	}


	return (node);
}


/*******************************************************************************
 *
 * FUNCTION:    Acpi_ds_method_data_get_value
 *
 * PARAMETERS:  Type                - Either MTH_TYPE_LOCAL or MTH_TYPE_ARG
 *              Index               - Which local_var or argument to get
 *              *Dest_desc           - Descriptor into which selected Arg
 *                                    or Local value should be copied
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Retrieve value of selected Arg or Local from the method frame
 *              at the current top of the method stack.
 *              Used only in Acpi_aml_resolve_to_value().
 *
 ******************************************************************************/

ACPI_STATUS
acpi_ds_method_data_get_value (
	u32                     type,
	u32                     index,
	ACPI_WALK_STATE         *walk_state,
	ACPI_OPERAND_OBJECT     **dest_desc)
{
	ACPI_STATUS             status;
	ACPI_OPERAND_OBJECT     **entry;
	ACPI_OPERAND_OBJECT     *object;


	/* Validate the object descriptor */

	if (!dest_desc) {
		return (AE_BAD_PARAMETER);
	}


	/* Get a pointer to the requested method stack entry */

	status = acpi_ds_method_data_get_entry (type, index, walk_state, &entry);
	if (ACPI_FAILURE (status)) {
		return (status);
	}

	/* Get the object from the method stack */

	object = *entry;


	/* Examine the returned object, it must be valid. */

	if (!object) {
		/*
		 * Index points to uninitialized object stack value.
		 * This means that either 1) The expected argument was
		 * not passed to the method, or 2) A local variable
		 * was referenced by the method (via the ASL)
		 * before it was initialized.  Either case is an error.
		 */

		switch (type)
		{
		case MTH_TYPE_ARG:
			return (AE_AML_UNINITIALIZED_ARG);
			break;

		case MTH_TYPE_LOCAL:
			return (AE_AML_UNINITIALIZED_LOCAL);
			break;
		}
	}


	/*
	 * Index points to initialized and valid object stack value.
	 * Return an additional reference to the object
	 */

	*dest_desc = object;
	acpi_cm_add_reference (object);

	return (AE_OK);
}


/*******************************************************************************
 *
 * FUNCTION:    Acpi_ds_method_data_delete_value
 *
 * PARAMETERS:  Type                - Either MTH_TYPE_LOCAL or MTH_TYPE_ARG
 *              Index               - Which local_var or argument to delete
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Delete the entry at Type:Index on the method stack.  Inserts
 *              a null into the stack slot after the object is deleted.
 *
 ******************************************************************************/

ACPI_STATUS
acpi_ds_method_data_delete_value (
	u32                     type,
	u32                     index,
	ACPI_WALK_STATE         *walk_state)
{
	ACPI_STATUS             status;
	ACPI_OPERAND_OBJECT     **entry;
	ACPI_OPERAND_OBJECT     *object;


	/* Get a pointer to the requested entry */

	status = acpi_ds_method_data_get_entry (type, index, walk_state, &entry);
	if (ACPI_FAILURE (status)) {
		return (status);
	}

	/* Get the current entry in this slot k */

	object = *entry;

	/*
	 * Undefine the Arg or Local by setting its descriptor
	 * pointer to NULL. Locals/Args can contain both
	 * ACPI_OPERAND_OBJECTS and ACPI_NAMESPACE_NODEs
	 */
	*entry = NULL;


	if ((object) &&
		(VALID_DESCRIPTOR_TYPE (object, ACPI_DESC_TYPE_INTERNAL)))
	{
		/*
		 * There is a valid object in this slot
		 * Decrement the reference count by one to balance the
		 * increment when the object was stored in the slot.
		 */

		acpi_cm_remove_reference (object);
	}


	return (AE_OK);
}


/*******************************************************************************
 *
 * FUNCTION:    Acpi_ds_method_data_set_value
 *
 * PARAMETERS:  Type                - Either MTH_TYPE_LOCAL or MTH_TYPE_ARG
 *              Index               - Which local_var or argument to set
 *              *Src_desc           - Value to be stored
 *              *Dest_desc          - Descriptor into which *Src_desc
 *                                    can be copied, or NULL if one must
 *                                    be allocated for the purpose.  If
 *                                    provided, this descriptor will be
 *                                    used for the new value.
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Store a value in an Arg or Local.  The Src_desc is installed
 *              as the new value for the Arg or Local and the reference count
 *              is incremented.
 *
 ******************************************************************************/

ACPI_STATUS
acpi_ds_method_data_set_value (
	u32                     type,
	u32                     index,
	ACPI_OPERAND_OBJECT     *src_desc,
	ACPI_WALK_STATE         *walk_state)
{
	ACPI_STATUS             status;
	ACPI_OPERAND_OBJECT     **entry;


	/* Parameter validation */

	if (!src_desc) {
		return (AE_BAD_PARAMETER);
	}


	/* Get a pointer to the requested method stack entry */

	status = acpi_ds_method_data_get_entry (type, index, walk_state, &entry);
	if (ACPI_FAILURE (status)) {
		goto cleanup;
	}

	if (*entry == src_desc) {
		goto cleanup;
	}


	/*
	 * If there is an object already in this slot, we either
	 * have to delete it, or if this is an argument and there
	 * is an object reference stored there, we have to do
	 * an indirect store!
	 */

	if (*entry) {
		/*
		 * Check for an indirect store if an argument
		 * contains an object reference (stored as an Node).
		 * We don't allow this automatic dereferencing for
		 * locals, since a store to a local should overwrite
		 * anything there, including an object reference.
		 *
		 * If both Arg0 and Local0 contain Ref_of (Local4):
		 *
		 * Store (1, Arg0)             - Causes indirect store to local4
		 * Store (1, Local0)           - Stores 1 in local0, overwriting
		 *                                  the reference to local4
		 * Store (1, De_refof (Local0)) - Causes indirect store to local4
		 *
		 * Weird, but true.
		 */

		if ((type == MTH_TYPE_ARG) &&
			(VALID_DESCRIPTOR_TYPE (*entry, ACPI_DESC_TYPE_NAMED)))
		{
			/* Detach an existing object from the Node */

			acpi_ns_detach_object ((ACPI_NAMESPACE_NODE *) *entry);

			/*
			 * Store this object into the Node
			 * (do the indirect store)
			 */

			status = acpi_ns_attach_object ((ACPI_NAMESPACE_NODE *) *entry, src_desc,
					   src_desc->common.type);
			return (status);
		}


		/*
		 * Otherwise, just delete the existing object
		 * before storing the new one
		 */

		acpi_ds_method_data_delete_value (type, index, walk_state);
	}


	/*
	 * Install the Obj_stack descriptor (*Src_desc) into
	 * the descriptor for the Arg or Local.
	 * Install the new object in the stack entry
	 * (increments the object reference count by one)
	 */

	status = acpi_ds_method_data_set_entry (type, index, src_desc, walk_state);
	if (ACPI_FAILURE (status)) {
		goto cleanup;
	}

	/* Normal exit */

	return (AE_OK);


	/* Error exit */

cleanup:

	return (status);
}