/* * Procedures for creating, accessing and interpreting the device tree. * * Paul Mackerras August 1996. * Copyright (C) 1996-2005 Paul Mackerras. * * Adapted for 64bit PowerPC by Dave Engebretsen and Peter Bergner. * {engebret|bergner}@us.ibm.com * * Adapted for sparc and sparc64 by David S. Miller davem@davemloft.net * * Reconsolidated from arch/x/kernel/prom.c by Stephen Rothwell and * Grant Likely. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ #include <linux/module.h> #include <linux/of.h> #include <linux/spinlock.h> #include <linux/slab.h> #include <linux/proc_fs.h> struct device_node *allnodes; struct device_node *of_chosen; /* use when traversing tree through the allnext, child, sibling, * or parent members of struct device_node. */ DEFINE_RWLOCK(devtree_lock); int of_n_addr_cells(struct device_node *np) { const __be32 *ip; do { if (np->parent) np = np->parent; ip = of_get_property(np, "#address-cells", NULL); if (ip) return be32_to_cpup(ip); } while (np->parent); /* No #address-cells property for the root node */ return OF_ROOT_NODE_ADDR_CELLS_DEFAULT; } EXPORT_SYMBOL(of_n_addr_cells); int of_n_size_cells(struct device_node *np) { const __be32 *ip; do { if (np->parent) np = np->parent; ip = of_get_property(np, "#size-cells", NULL); if (ip) return be32_to_cpup(ip); } while (np->parent); /* No #size-cells property for the root node */ return OF_ROOT_NODE_SIZE_CELLS_DEFAULT; } EXPORT_SYMBOL(of_n_size_cells); #if !defined(CONFIG_SPARC) /* SPARC doesn't do ref counting (yet) */ /** * of_node_get - Increment refcount of a node * @node: Node to inc refcount, NULL is supported to * simplify writing of callers * * Returns node. */ struct device_node *of_node_get(struct device_node *node) { if (node) kref_get(&node->kref); return node; } EXPORT_SYMBOL(of_node_get); static inline struct device_node *kref_to_device_node(struct kref *kref) { return container_of(kref, struct device_node, kref); } /** * of_node_release - release a dynamically allocated node * @kref: kref element of the node to be released * * In of_node_put() this function is passed to kref_put() * as the destructor. */ static void of_node_release(struct kref *kref) { struct device_node *node = kref_to_device_node(kref); struct property *prop = node->properties; /* We should never be releasing nodes that haven't been detached. */ if (!of_node_check_flag(node, OF_DETACHED)) { pr_err("ERROR: Bad of_node_put() on %s\n", node->full_name); dump_stack(); kref_init(&node->kref); return; } if (!of_node_check_flag(node, OF_DYNAMIC)) return; while (prop) { struct property *next = prop->next; kfree(prop->name); kfree(prop->value); kfree(prop); prop = next; if (!prop) { prop = node->deadprops; node->deadprops = NULL; } } kfree(node->full_name); kfree(node->data); kfree(node); } /** * of_node_put - Decrement refcount of a node * @node: Node to dec refcount, NULL is supported to * simplify writing of callers * */ void of_node_put(struct device_node *node) { if (node) kref_put(&node->kref, of_node_release); } EXPORT_SYMBOL(of_node_put); #endif /* !CONFIG_SPARC */ struct property *of_find_property(const struct device_node *np, const char *name, int *lenp) { struct property *pp; if (!np) return NULL; read_lock(&devtree_lock); for (pp = np->properties; pp != 0; pp = pp->next) { if (of_prop_cmp(pp->name, name) == 0) { if (lenp != 0) *lenp = pp->length; break; } } read_unlock(&devtree_lock); return pp; } EXPORT_SYMBOL(of_find_property); /** * of_find_all_nodes - Get next node in global list * @prev: Previous node or NULL to start iteration * of_node_put() will be called on it * * Returns a node pointer with refcount incremented, use * of_node_put() on it when done. */ struct device_node *of_find_all_nodes(struct device_node *prev) { struct device_node *np; read_lock(&devtree_lock); np = prev ? prev->allnext : allnodes; for (; np != NULL; np = np->allnext) if (of_node_get(np)) break; of_node_put(prev); read_unlock(&devtree_lock); return np; } EXPORT_SYMBOL(of_find_all_nodes); /* * Find a property with a given name for a given node * and return the value. */ const void *of_get_property(const struct device_node *np, const char *name, int *lenp) { struct property *pp = of_find_property(np, name, lenp); return pp ? pp->value : NULL; } EXPORT_SYMBOL(of_get_property); /** Checks if the given "compat" string matches one of the strings in * the device's "compatible" property */ int of_device_is_compatible(const struct device_node *device, const char *compat) { const char* cp; int cplen, l; cp = of_get_property(device, "compatible", &cplen); if (cp == NULL) return 0; while (cplen > 0) { if (of_compat_cmp(cp, compat, strlen(compat)) == 0) return 1; l = strlen(cp) + 1; cp += l; cplen -= l; } return 0; } EXPORT_SYMBOL(of_device_is_compatible); /** * of_machine_is_compatible - Test root of device tree for a given compatible value * @compat: compatible string to look for in root node's compatible property. * * Returns true if the root node has the given value in its * compatible property. */ int of_machine_is_compatible(const char *compat) { struct device_node *root; int rc = 0; root = of_find_node_by_path("/"); if (root) { rc = of_device_is_compatible(root, compat); of_node_put(root); } return rc; } EXPORT_SYMBOL(of_machine_is_compatible); /** * of_device_is_available - check if a device is available for use * * @device: Node to check for availability * * Returns 1 if the status property is absent or set to "okay" or "ok", * 0 otherwise */ int of_device_is_available(const struct device_node *device) { const char *status; int statlen; status = of_get_property(device, "status", &statlen); if (status == NULL) return 1; if (statlen > 0) { if (!strcmp(status, "okay") || !strcmp(status, "ok")) return 1; } return 0; } EXPORT_SYMBOL(of_device_is_available); /** * of_get_parent - Get a node's parent if any * @node: Node to get parent * * Returns a node pointer with refcount incremented, use * of_node_put() on it when done. */ struct device_node *of_get_parent(const struct device_node *node) { struct device_node *np; if (!node) return NULL; read_lock(&devtree_lock); np = of_node_get(node->parent); read_unlock(&devtree_lock); return np; } EXPORT_SYMBOL(of_get_parent); /** * of_get_next_parent - Iterate to a node's parent * @node: Node to get parent of * * This is like of_get_parent() except that it drops the * refcount on the passed node, making it suitable for iterating * through a node's parents. * * Returns a node pointer with refcount incremented, use * of_node_put() on it when done. */ struct device_node *of_get_next_parent(struct device_node *node) { struct device_node *parent; if (!node) return NULL; read_lock(&devtree_lock); parent = of_node_get(node->parent); of_node_put(node); read_unlock(&devtree_lock); return parent; } /** * of_get_next_child - Iterate a node childs * @node: parent node * @prev: previous child of the parent node, or NULL to get first * * Returns a node pointer with refcount incremented, use * of_node_put() on it when done. */ struct device_node *of_get_next_child(const struct device_node *node, struct device_node *prev) { struct device_node *next; read_lock(&devtree_lock); next = prev ? prev->sibling : node->child; for (; next; next = next->sibling) if (of_node_get(next)) break; of_node_put(prev); read_unlock(&devtree_lock); return next; } EXPORT_SYMBOL(of_get_next_child); /** * of_find_node_by_path - Find a node matching a full OF path * @path: The full path to match * * Returns a node pointer with refcount incremented, use * of_node_put() on it when done. */ struct device_node *of_find_node_by_path(const char *path) { struct device_node *np = allnodes; read_lock(&devtree_lock); for (; np; np = np->allnext) { if (np->full_name && (of_node_cmp(np->full_name, path) == 0) && of_node_get(np)) break; } read_unlock(&devtree_lock); return np; } EXPORT_SYMBOL(of_find_node_by_path); /** * of_find_node_by_name - Find a node by its "name" property * @from: The node to start searching from or NULL, the node * you pass will not be searched, only the next one * will; typically, you pass what the previous call * returned. of_node_put() will be called on it * @name: The name string to match against * * Returns a node pointer with refcount incremented, use * of_node_put() on it when done. */ struct device_node *of_find_node_by_name(struct device_node *from, const char *name) { struct device_node *np; read_lock(&devtree_lock); np = from ? from->allnext : allnodes; for (; np; np = np->allnext) if (np->name && (of_node_cmp(np->name, name) == 0) && of_node_get(np)) break; of_node_put(from); read_unlock(&devtree_lock); return np; } EXPORT_SYMBOL(of_find_node_by_name); /** * of_find_node_by_type - Find a node by its "device_type" property * @from: The node to start searching from, or NULL to start searching * the entire device tree. The node you pass will not be * searched, only the next one will; typically, you pass * what the previous call returned. of_node_put() will be * called on from for you. * @type: The type string to match against * * Returns a node pointer with refcount incremented, use * of_node_put() on it when done. */ struct device_node *of_find_node_by_type(struct device_node *from, const char *type) { struct device_node *np; read_lock(&devtree_lock); np = from ? from->allnext : allnodes; for (; np; np = np->allnext) if (np->type && (of_node_cmp(np->type, type) == 0) && of_node_get(np)) break; of_node_put(from); read_unlock(&devtree_lock); return np; } EXPORT_SYMBOL(of_find_node_by_type); /** * of_find_compatible_node - Find a node based on type and one of the * tokens in its "compatible" property * @from: The node to start searching from or NULL, the node * you pass will not be searched, only the next one * will; typically, you pass what the previous call * returned. of_node_put() will be called on it * @type: The type string to match "device_type" or NULL to ignore * @compatible: The string to match to one of the tokens in the device * "compatible" list. * * Returns a node pointer with refcount incremented, use * of_node_put() on it when done. */ struct device_node *of_find_compatible_node(struct device_node *from, const char *type, const char *compatible) { struct device_node *np; read_lock(&devtree_lock); np = from ? from->allnext : allnodes; for (; np; np = np->allnext) { if (type && !(np->type && (of_node_cmp(np->type, type) == 0))) continue; if (of_device_is_compatible(np, compatible) && of_node_get(np)) break; } of_node_put(from); read_unlock(&devtree_lock); return np; } EXPORT_SYMBOL(of_find_compatible_node); /** * of_find_node_with_property - Find a node which has a property with * the given name. * @from: The node to start searching from or NULL, the node * you pass will not be searched, only the next one * will; typically, you pass what the previous call * returned. of_node_put() will be called on it * @prop_name: The name of the property to look for. * * Returns a node pointer with refcount incremented, use * of_node_put() on it when done. */ struct device_node *of_find_node_with_property(struct device_node *from, const char *prop_name) { struct device_node *np; struct property *pp; read_lock(&devtree_lock); np = from ? from->allnext : allnodes; for (; np; np = np->allnext) { for (pp = np->properties; pp != 0; pp = pp->next) { if (of_prop_cmp(pp->name, prop_name) == 0) { of_node_get(np); goto out; } } } out: of_node_put(from); read_unlock(&devtree_lock); return np; } EXPORT_SYMBOL(of_find_node_with_property); /** * of_match_node - Tell if an device_node has a matching of_match structure * @matches: array of of device match structures to search in * @node: the of device structure to match against * * Low level utility function used by device matching. */ const struct of_device_id *of_match_node(const struct of_device_id *matches, const struct device_node *node) { if (!matches) return NULL; while (matches->name[0] || matches->type[0] || matches->compatible[0]) { int match = 1; if (matches->name[0]) match &= node->name && !strcmp(matches->name, node->name); if (matches->type[0]) match &= node->type && !strcmp(matches->type, node->type); if (matches->compatible[0]) match &= of_device_is_compatible(node, matches->compatible); if (match) return matches; matches++; } return NULL; } EXPORT_SYMBOL(of_match_node); /** * of_find_matching_node - Find a node based on an of_device_id match * table. * @from: The node to start searching from or NULL, the node * you pass will not be searched, only the next one * will; typically, you pass what the previous call * returned. of_node_put() will be called on it * @matches: array of of device match structures to search in * * Returns a node pointer with refcount incremented, use * of_node_put() on it when done. */ struct device_node *of_find_matching_node(struct device_node *from, const struct of_device_id *matches) { struct device_node *np; read_lock(&devtree_lock); np = from ? from->allnext : allnodes; for (; np; np = np->allnext) { if (of_match_node(matches, np) && of_node_get(np)) break; } of_node_put(from); read_unlock(&devtree_lock); return np; } EXPORT_SYMBOL(of_find_matching_node); /** * of_modalias_node - Lookup appropriate modalias for a device node * @node: pointer to a device tree node * @modalias: Pointer to buffer that modalias value will be copied into * @len: Length of modalias value * * Based on the value of the compatible property, this routine will attempt * to choose an appropriate modalias value for a particular device tree node. * It does this by stripping the manufacturer prefix (as delimited by a ',') * from the first entry in the compatible list property. * * This routine returns 0 on success, <0 on failure. */ int of_modalias_node(struct device_node *node, char *modalias, int len) { const char *compatible, *p; int cplen; compatible = of_get_property(node, "compatible", &cplen); if (!compatible || strlen(compatible) > cplen) return -ENODEV; p = strchr(compatible, ','); strlcpy(modalias, p ? p + 1 : compatible, len); return 0; } EXPORT_SYMBOL_GPL(of_modalias_node); /** * of_find_node_by_phandle - Find a node given a phandle * @handle: phandle of the node to find * * Returns a node pointer with refcount incremented, use * of_node_put() on it when done. */ struct device_node *of_find_node_by_phandle(phandle handle) { struct device_node *np; read_lock(&devtree_lock); for (np = allnodes; np; np = np->allnext) if (np->phandle == handle) break; of_node_get(np); read_unlock(&devtree_lock); return np; } EXPORT_SYMBOL(of_find_node_by_phandle); /** * of_parse_phandle - Resolve a phandle property to a device_node pointer * @np: Pointer to device node holding phandle property * @phandle_name: Name of property holding a phandle value * @index: For properties holding a table of phandles, this is the index into * the table * * Returns the device_node pointer with refcount incremented. Use * of_node_put() on it when done. */ struct device_node * of_parse_phandle(struct device_node *np, const char *phandle_name, int index) { const __be32 *phandle; int size; phandle = of_get_property(np, phandle_name, &size); if ((!phandle) || (size < sizeof(*phandle) * (index + 1))) return NULL; return of_find_node_by_phandle(be32_to_cpup(phandle + index)); } EXPORT_SYMBOL(of_parse_phandle); /** * of_parse_phandles_with_args - Find a node pointed by phandle in a list * @np: pointer to a device tree node containing a list * @list_name: property name that contains a list * @cells_name: property name that specifies phandles' arguments count * @index: index of a phandle to parse out * @out_node: optional pointer to device_node struct pointer (will be filled) * @out_args: optional pointer to arguments pointer (will be filled) * * This function is useful to parse lists of phandles and their arguments. * Returns 0 on success and fills out_node and out_args, on error returns * appropriate errno value. * * Example: * * phandle1: node1 { * #list-cells = <2>; * } * * phandle2: node2 { * #list-cells = <1>; * } * * node3 { * list = <&phandle1 1 2 &phandle2 3>; * } * * To get a device_node of the `node2' node you may call this: * of_parse_phandles_with_args(node3, "list", "#list-cells", 2, &node2, &args); */ int of_parse_phandles_with_args(struct device_node *np, const char *list_name, const char *cells_name, int index, struct device_node **out_node, const void **out_args) { int ret = -EINVAL; const __be32 *list; const __be32 *list_end; int size; int cur_index = 0; struct device_node *node = NULL; const void *args = NULL; list = of_get_property(np, list_name, &size); if (!list) { ret = -ENOENT; goto err0; } list_end = list + size / sizeof(*list); while (list < list_end) { const __be32 *cells; phandle phandle; phandle = be32_to_cpup(list++); args = list; /* one cell hole in the list = <>; */ if (!phandle) goto next; node = of_find_node_by_phandle(phandle); if (!node) { pr_debug("%s: could not find phandle\n", np->full_name); goto err0; } cells = of_get_property(node, cells_name, &size); if (!cells || size != sizeof(*cells)) { pr_debug("%s: could not get %s for %s\n", np->full_name, cells_name, node->full_name); goto err1; } list += be32_to_cpup(cells); if (list > list_end) { pr_debug("%s: insufficient arguments length\n", np->full_name); goto err1; } next: if (cur_index == index) break; of_node_put(node); node = NULL; args = NULL; cur_index++; } if (!node) { /* * args w/o node indicates that the loop above has stopped at * the 'hole' cell. Report this differently. */ if (args) ret = -EEXIST; else ret = -ENOENT; goto err0; } if (out_node) *out_node = node; if (out_args) *out_args = args; return 0; err1: of_node_put(node); err0: pr_debug("%s failed with status %d\n", __func__, ret); return ret; } EXPORT_SYMBOL(of_parse_phandles_with_args); /** * prom_add_property - Add a property to a node */ int prom_add_property(struct device_node *np, struct property *prop) { struct property **next; unsigned long flags; prop->next = NULL; write_lock_irqsave(&devtree_lock, flags); next = &np->properties; while (*next) { if (strcmp(prop->name, (*next)->name) == 0) { /* duplicate ! don't insert it */ write_unlock_irqrestore(&devtree_lock, flags); return -1; } next = &(*next)->next; } *next = prop; write_unlock_irqrestore(&devtree_lock, flags); #ifdef CONFIG_PROC_DEVICETREE /* try to add to proc as well if it was initialized */ if (np->pde) proc_device_tree_add_prop(np->pde, prop); #endif /* CONFIG_PROC_DEVICETREE */ return 0; } /** * prom_remove_property - Remove a property from a node. * * Note that we don't actually remove it, since we have given out * who-knows-how-many pointers to the data using get-property. * Instead we just move the property to the "dead properties" * list, so it won't be found any more. */ int prom_remove_property(struct device_node *np, struct property *prop) { struct property **next; unsigned long flags; int found = 0; write_lock_irqsave(&devtree_lock, flags); next = &np->properties; while (*next) { if (*next == prop) { /* found the node */ *next = prop->next; prop->next = np->deadprops; np->deadprops = prop; found = 1; break; } next = &(*next)->next; } write_unlock_irqrestore(&devtree_lock, flags); if (!found) return -ENODEV; #ifdef CONFIG_PROC_DEVICETREE /* try to remove the proc node as well */ if (np->pde) proc_device_tree_remove_prop(np->pde, prop); #endif /* CONFIG_PROC_DEVICETREE */ return 0; } /* * prom_update_property - Update a property in a node. * * Note that we don't actually remove it, since we have given out * who-knows-how-many pointers to the data using get-property. * Instead we just move the property to the "dead properties" list, * and add the new property to the property list */ int prom_update_property(struct device_node *np, struct property *newprop, struct property *oldprop) { struct property **next; unsigned long flags; int found = 0; write_lock_irqsave(&devtree_lock, flags); next = &np->properties; while (*next) { if (*next == oldprop) { /* found the node */ newprop->next = oldprop->next; *next = newprop; oldprop->next = np->deadprops; np->deadprops = oldprop; found = 1; break; } next = &(*next)->next; } write_unlock_irqrestore(&devtree_lock, flags); if (!found) return -ENODEV; #ifdef CONFIG_PROC_DEVICETREE /* try to add to proc as well if it was initialized */ if (np->pde) proc_device_tree_update_prop(np->pde, newprop, oldprop); #endif /* CONFIG_PROC_DEVICETREE */ return 0; } #if defined(CONFIG_OF_DYNAMIC) /* * Support for dynamic device trees. * * On some platforms, the device tree can be manipulated at runtime. * The routines in this section support adding, removing and changing * device tree nodes. */ /** * of_attach_node - Plug a device node into the tree and global list. */ void of_attach_node(struct device_node *np) { unsigned long flags; write_lock_irqsave(&devtree_lock, flags); np->sibling = np->parent->child; np->allnext = allnodes; np->parent->child = np; allnodes = np; write_unlock_irqrestore(&devtree_lock, flags); } /** * of_detach_node - "Unplug" a node from the device tree. * * The caller must hold a reference to the node. The memory associated with * the node is not freed until its refcount goes to zero. */ void of_detach_node(struct device_node *np) { struct device_node *parent; unsigned long flags; write_lock_irqsave(&devtree_lock, flags); parent = np->parent; if (!parent) goto out_unlock; if (allnodes == np) allnodes = np->allnext; else { struct device_node *prev; for (prev = allnodes; prev->allnext != np; prev = prev->allnext) ; prev->allnext = np->allnext; } if (parent->child == np) parent->child = np->sibling; else { struct device_node *prevsib; for (prevsib = np->parent->child; prevsib->sibling != np; prevsib = prevsib->sibling) ; prevsib->sibling = np->sibling; } of_node_set_flag(np, OF_DETACHED); out_unlock: write_unlock_irqrestore(&devtree_lock, flags); } #endif /* defined(CONFIG_OF_DYNAMIC) */