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Diffstat (limited to '')
-rw-r--r-- | drivers/acpi/acpica/nswalk.c | 327 |
1 files changed, 327 insertions, 0 deletions
diff --git a/drivers/acpi/acpica/nswalk.c b/drivers/acpi/acpica/nswalk.c new file mode 100644 index 000000000..82a0dae34 --- /dev/null +++ b/drivers/acpi/acpica/nswalk.c @@ -0,0 +1,327 @@ +// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0 +/****************************************************************************** + * + * Module Name: nswalk - Functions for walking the ACPI namespace + * + * Copyright (C) 2000 - 2022, Intel Corp. + * + *****************************************************************************/ + +#include <acpi/acpi.h> +#include "accommon.h" +#include "acnamesp.h" + +#define _COMPONENT ACPI_NAMESPACE +ACPI_MODULE_NAME("nswalk") + +/******************************************************************************* + * + * FUNCTION: acpi_ns_get_next_node + * + * PARAMETERS: parent_node - Parent node whose children we are + * getting + * child_node - Previous child that was found. + * The NEXT child will be returned + * + * RETURN: struct acpi_namespace_node - Pointer to the NEXT child or NULL if + * none is found. + * + * DESCRIPTION: Return the next peer node within the namespace. If Handle + * is valid, Scope is ignored. Otherwise, the first node + * within Scope is returned. + * + ******************************************************************************/ +struct acpi_namespace_node *acpi_ns_get_next_node(struct acpi_namespace_node + *parent_node, + struct acpi_namespace_node + *child_node) +{ + ACPI_FUNCTION_ENTRY(); + + if (!child_node) { + + /* It's really the parent's _scope_ that we want */ + + return (parent_node->child); + } + + /* Otherwise just return the next peer */ + + return (child_node->peer); +} + +/******************************************************************************* + * + * FUNCTION: acpi_ns_get_next_node_typed + * + * PARAMETERS: type - Type of node to be searched for + * parent_node - Parent node whose children we are + * getting + * child_node - Previous child that was found. + * The NEXT child will be returned + * + * RETURN: struct acpi_namespace_node - Pointer to the NEXT child or NULL if + * none is found. + * + * DESCRIPTION: Return the next peer node within the namespace. If Handle + * is valid, Scope is ignored. Otherwise, the first node + * within Scope is returned. + * + ******************************************************************************/ + +struct acpi_namespace_node *acpi_ns_get_next_node_typed(acpi_object_type type, + struct + acpi_namespace_node + *parent_node, + struct + acpi_namespace_node + *child_node) +{ + struct acpi_namespace_node *next_node = NULL; + + ACPI_FUNCTION_ENTRY(); + + next_node = acpi_ns_get_next_node(parent_node, child_node); + + + /* If any type is OK, we are done */ + + if (type == ACPI_TYPE_ANY) { + + /* next_node is NULL if we are at the end-of-list */ + + return (next_node); + } + + /* Must search for the node -- but within this scope only */ + + while (next_node) { + + /* If type matches, we are done */ + + if (next_node->type == type) { + return (next_node); + } + + /* Otherwise, move on to the next peer node */ + + next_node = next_node->peer; + } + + /* Not found */ + + return (NULL); +} + +/******************************************************************************* + * + * FUNCTION: acpi_ns_walk_namespace + * + * PARAMETERS: type - acpi_object_type to search for + * start_node - Handle in namespace where search begins + * max_depth - Depth to which search is to reach + * flags - Whether to unlock the NS before invoking + * the callback routine + * descending_callback - Called during tree descent + * when an object of "Type" is found + * ascending_callback - Called during tree ascent + * when an object of "Type" is found + * context - Passed to user function(s) above + * return_value - from the user_function if terminated + * early. Otherwise, returns NULL. + * RETURNS: Status + * + * DESCRIPTION: Performs a modified depth-first walk of the namespace tree, + * starting (and ending) at the node specified by start_handle. + * The callback function is called whenever a node that matches + * the type parameter is found. If the callback function returns + * a non-zero value, the search is terminated immediately and + * this value is returned to the caller. + * + * The point of this procedure is to provide a generic namespace + * walk routine that can be called from multiple places to + * provide multiple services; the callback function(s) can be + * tailored to each task, whether it is a print function, + * a compare function, etc. + * + ******************************************************************************/ + +acpi_status +acpi_ns_walk_namespace(acpi_object_type type, + acpi_handle start_node, + u32 max_depth, + u32 flags, + acpi_walk_callback descending_callback, + acpi_walk_callback ascending_callback, + void *context, void **return_value) +{ + acpi_status status; + acpi_status mutex_status; + struct acpi_namespace_node *child_node; + struct acpi_namespace_node *parent_node; + acpi_object_type child_type; + u32 level; + u8 node_previously_visited = FALSE; + + ACPI_FUNCTION_TRACE(ns_walk_namespace); + + /* Special case for the namespace Root Node */ + + if (start_node == ACPI_ROOT_OBJECT) { + start_node = acpi_gbl_root_node; + if (!start_node) { + return_ACPI_STATUS(AE_NO_NAMESPACE); + } + } + + /* Null child means "get first node" */ + + parent_node = start_node; + child_node = acpi_ns_get_next_node(parent_node, NULL); + child_type = ACPI_TYPE_ANY; + level = 1; + + /* + * Traverse the tree of nodes until we bubble back up to where we + * started. When Level is zero, the loop is done because we have + * bubbled up to (and passed) the original parent handle (start_entry) + */ + while (level > 0 && child_node) { + status = AE_OK; + + /* Found next child, get the type if we are not searching for ANY */ + + if (type != ACPI_TYPE_ANY) { + child_type = child_node->type; + } + + /* + * Ignore all temporary namespace nodes (created during control + * method execution) unless told otherwise. These temporary nodes + * can cause a race condition because they can be deleted during + * the execution of the user function (if the namespace is + * unlocked before invocation of the user function.) Only the + * debugger namespace dump will examine the temporary nodes. + */ + if ((child_node->flags & ANOBJ_TEMPORARY) && + !(flags & ACPI_NS_WALK_TEMP_NODES)) { + status = AE_CTRL_DEPTH; + } + + /* Type must match requested type */ + + else if (child_type == type) { + /* + * Found a matching node, invoke the user callback function. + * Unlock the namespace if flag is set. + */ + if (flags & ACPI_NS_WALK_UNLOCK) { + mutex_status = + acpi_ut_release_mutex(ACPI_MTX_NAMESPACE); + if (ACPI_FAILURE(mutex_status)) { + return_ACPI_STATUS(mutex_status); + } + } + + /* + * Invoke the user function, either descending, ascending, + * or both. + */ + if (!node_previously_visited) { + if (descending_callback) { + status = + descending_callback(child_node, + level, context, + return_value); + } + } else { + if (ascending_callback) { + status = + ascending_callback(child_node, + level, context, + return_value); + } + } + + if (flags & ACPI_NS_WALK_UNLOCK) { + mutex_status = + acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE); + if (ACPI_FAILURE(mutex_status)) { + return_ACPI_STATUS(mutex_status); + } + } + + switch (status) { + case AE_OK: + case AE_CTRL_DEPTH: + + /* Just keep going */ + break; + + case AE_CTRL_TERMINATE: + + /* Exit now, with OK status */ + + return_ACPI_STATUS(AE_OK); + + default: + + /* All others are valid exceptions */ + + return_ACPI_STATUS(status); + } + } + + /* + * Depth first search: Attempt to go down another level in the + * namespace if we are allowed to. Don't go any further if we have + * reached the caller specified maximum depth or if the user + * function has specified that the maximum depth has been reached. + */ + if (!node_previously_visited && + (level < max_depth) && (status != AE_CTRL_DEPTH)) { + if (child_node->child) { + + /* There is at least one child of this node, visit it */ + + level++; + parent_node = child_node; + child_node = + acpi_ns_get_next_node(parent_node, NULL); + continue; + } + } + + /* No more children, re-visit this node */ + + if (!node_previously_visited) { + node_previously_visited = TRUE; + continue; + } + + /* No more children, visit peers */ + + child_node = acpi_ns_get_next_node(parent_node, child_node); + if (child_node) { + node_previously_visited = FALSE; + } + + /* No peers, re-visit parent */ + + else { + /* + * No more children of this node (acpi_ns_get_next_node failed), go + * back upwards in the namespace tree to the node's parent. + */ + level--; + child_node = parent_node; + parent_node = parent_node->parent; + + node_previously_visited = TRUE; + } + } + + /* Complete walk, not terminated by user function */ + + return_ACPI_STATUS(AE_OK); +} |