diff options
Diffstat (limited to 'drivers/of/base.c')
| -rw-r--r-- | drivers/of/base.c | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/drivers/of/base.c b/drivers/of/base.c index 3ff22e32b60..b970562e011 100644 --- a/drivers/of/base.c +++ b/drivers/of/base.c @@ -17,14 +17,39 @@ * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ +#include <linux/ctype.h> #include <linux/module.h> #include <linux/of.h> #include <linux/spinlock.h> #include <linux/slab.h> #include <linux/proc_fs.h> +/** + * struct alias_prop - Alias property in 'aliases' node + * @link: List node to link the structure in aliases_lookup list + * @alias: Alias property name + * @np: Pointer to device_node that the alias stands for + * @id: Index value from end of alias name + * @stem: Alias string without the index + * + * The structure represents one alias property of 'aliases' node as + * an entry in aliases_lookup list. + */ +struct alias_prop { + struct list_head link; + const char *alias; + struct device_node *np; + int id; + char stem[0]; +}; + +static LIST_HEAD(aliases_lookup); + struct device_node *allnodes; struct device_node *of_chosen; +struct device_node *of_aliases; + +static DEFINE_MUTEX(of_aliases_mutex); /* use when traversing tree through the allnext, child, sibling, * or parent members of struct device_node. @@ -632,6 +657,35 @@ int of_property_read_u32_array(const struct device_node *np, EXPORT_SYMBOL_GPL(of_property_read_u32_array); /** + * of_property_read_u64 - Find and read a 64 bit integer from a property + * @np: device node from which the property value is to be read. + * @propname: name of the property to be searched. + * @out_value: pointer to return value, modified only if return value is 0. + * + * Search for a property in a device node and read a 64-bit value from + * it. Returns 0 on success, -EINVAL if the property does not exist, + * -ENODATA if property does not have a value, and -EOVERFLOW if the + * property data isn't large enough. + * + * The out_value is modified only if a valid u64 value can be decoded. + */ +int of_property_read_u64(const struct device_node *np, const char *propname, + u64 *out_value) +{ + struct property *prop = of_find_property(np, propname, NULL); + + if (!prop) + return -EINVAL; + if (!prop->value) + return -ENODATA; + if (sizeof(*out_value) > prop->length) + return -EOVERFLOW; + *out_value = of_read_number(prop->value, 2); + return 0; +} +EXPORT_SYMBOL_GPL(of_property_read_u64); + +/** * of_property_read_string - Find and read a string from a property * @np: device node from which the property value is to be read. * @propname: name of the property to be searched. @@ -988,3 +1042,99 @@ out_unlock: } #endif /* defined(CONFIG_OF_DYNAMIC) */ +static void of_alias_add(struct alias_prop *ap, struct device_node *np, + int id, const char *stem, int stem_len) +{ + ap->np = np; + ap->id = id; + strncpy(ap->stem, stem, stem_len); + ap->stem[stem_len] = 0; + list_add_tail(&ap->link, &aliases_lookup); + pr_debug("adding DT alias:%s: stem=%s id=%i node=%s\n", + ap->alias, ap->stem, ap->id, np ? np->full_name : NULL); +} + +/** + * of_alias_scan - Scan all properties of 'aliases' node + * + * The function scans all the properties of 'aliases' node and populate + * the the global lookup table with the properties. It returns the + * number of alias_prop found, or error code in error case. + * + * @dt_alloc: An allocator that provides a virtual address to memory + * for the resulting tree + */ +void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align)) +{ + struct property *pp; + + of_chosen = of_find_node_by_path("/chosen"); + if (of_chosen == NULL) + of_chosen = of_find_node_by_path("/chosen@0"); + of_aliases = of_find_node_by_path("/aliases"); + if (!of_aliases) + return; + + for_each_property(pp, of_aliases->properties) { + const char *start = pp->name; + const char *end = start + strlen(start); + struct device_node *np; + struct alias_prop *ap; + int id, len; + + /* Skip those we do not want to proceed */ + if (!strcmp(pp->name, "name") || + !strcmp(pp->name, "phandle") || + !strcmp(pp->name, "linux,phandle")) + continue; + + np = of_find_node_by_path(pp->value); + if (!np) + continue; + + /* walk the alias backwards to extract the id and work out + * the 'stem' string */ + while (isdigit(*(end-1)) && end > start) + end--; + len = end - start; + + if (kstrtoint(end, 10, &id) < 0) + continue; + + /* Allocate an alias_prop with enough space for the stem */ + ap = dt_alloc(sizeof(*ap) + len + 1, 4); + if (!ap) + continue; + ap->alias = start; + of_alias_add(ap, np, id, start, len); + } +} + +/** + * of_alias_get_id - Get alias id for the given device_node + * @np: Pointer to the given device_node + * @stem: Alias stem of the given device_node + * + * The function travels the lookup table to get alias id for the given + * device_node and alias stem. It returns the alias id if find it. + */ +int of_alias_get_id(struct device_node *np, const char *stem) +{ + struct alias_prop *app; + int id = -ENODEV; + + mutex_lock(&of_aliases_mutex); + list_for_each_entry(app, &aliases_lookup, link) { + if (strcmp(app->stem, stem) != 0) + continue; + + if (np == app->np) { + id = app->id; + break; + } + } + mutex_unlock(&of_aliases_mutex); + + return id; +} +EXPORT_SYMBOL_GPL(of_alias_get_id); |