diff options
author | Shawn Guo <shawn.guo@linaro.org> | 2011-08-15 03:28:14 -0400 |
---|---|---|
committer | Grant Likely <grant.likely@secretlab.ca> | 2011-09-22 13:12:10 -0400 |
commit | 611cad720148c899db5a383c1c676fd820df7023 (patch) | |
tree | 780adeaa4418b7b1e76d4a3b8fe600f04475c7df /drivers/of/base.c | |
parent | a81dd364de50bc1eb1519af0ecfa100753a09351 (diff) |
dt: add of_alias_scan and of_alias_get_id
The patch adds function of_alias_scan to populate a global lookup
table with the properties of 'aliases' node and function
of_alias_get_id for drivers to find alias id from the lookup table.
v3: Split out automatic addition of aliases on id lookup so that it can be
debated separately from the core functionality.
v2: - Add of_chosen/of_aliases populating and of_alias_scan() invocation
for OF_PROMTREE.
- Add locking
- rework parse loop
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Diffstat (limited to 'drivers/of/base.c')
-rw-r--r-- | drivers/of/base.c | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/drivers/of/base.c b/drivers/of/base.c index 3ff22e32b602..8abde58cbe82 100644 --- a/drivers/of/base.c +++ b/drivers/of/base.c | |||
@@ -17,14 +17,39 @@ | |||
17 | * as published by the Free Software Foundation; either version | 17 | * as published by the Free Software Foundation; either version |
18 | * 2 of the License, or (at your option) any later version. | 18 | * 2 of the License, or (at your option) any later version. |
19 | */ | 19 | */ |
20 | #include <linux/ctype.h> | ||
20 | #include <linux/module.h> | 21 | #include <linux/module.h> |
21 | #include <linux/of.h> | 22 | #include <linux/of.h> |
22 | #include <linux/spinlock.h> | 23 | #include <linux/spinlock.h> |
23 | #include <linux/slab.h> | 24 | #include <linux/slab.h> |
24 | #include <linux/proc_fs.h> | 25 | #include <linux/proc_fs.h> |
25 | 26 | ||
27 | /** | ||
28 | * struct alias_prop - Alias property in 'aliases' node | ||
29 | * @link: List node to link the structure in aliases_lookup list | ||
30 | * @alias: Alias property name | ||
31 | * @np: Pointer to device_node that the alias stands for | ||
32 | * @id: Index value from end of alias name | ||
33 | * @stem: Alias string without the index | ||
34 | * | ||
35 | * The structure represents one alias property of 'aliases' node as | ||
36 | * an entry in aliases_lookup list. | ||
37 | */ | ||
38 | struct alias_prop { | ||
39 | struct list_head link; | ||
40 | const char *alias; | ||
41 | struct device_node *np; | ||
42 | int id; | ||
43 | char stem[0]; | ||
44 | }; | ||
45 | |||
46 | static LIST_HEAD(aliases_lookup); | ||
47 | |||
26 | struct device_node *allnodes; | 48 | struct device_node *allnodes; |
27 | struct device_node *of_chosen; | 49 | struct device_node *of_chosen; |
50 | struct device_node *of_aliases; | ||
51 | |||
52 | static DEFINE_MUTEX(of_aliases_mutex); | ||
28 | 53 | ||
29 | /* use when traversing tree through the allnext, child, sibling, | 54 | /* use when traversing tree through the allnext, child, sibling, |
30 | * or parent members of struct device_node. | 55 | * or parent members of struct device_node. |
@@ -988,3 +1013,99 @@ out_unlock: | |||
988 | } | 1013 | } |
989 | #endif /* defined(CONFIG_OF_DYNAMIC) */ | 1014 | #endif /* defined(CONFIG_OF_DYNAMIC) */ |
990 | 1015 | ||
1016 | static void of_alias_add(struct alias_prop *ap, struct device_node *np, | ||
1017 | int id, const char *stem, int stem_len) | ||
1018 | { | ||
1019 | ap->np = np; | ||
1020 | ap->id = id; | ||
1021 | strncpy(ap->stem, stem, stem_len); | ||
1022 | ap->stem[stem_len] = 0; | ||
1023 | list_add_tail(&ap->link, &aliases_lookup); | ||
1024 | pr_debug("adding DT alias:%s: stem=%s id=%i node=%s\n", | ||
1025 | ap->alias, ap->stem, ap->id, np ? np->full_name : NULL); | ||
1026 | } | ||
1027 | |||
1028 | /** | ||
1029 | * of_alias_scan - Scan all properties of 'aliases' node | ||
1030 | * | ||
1031 | * The function scans all the properties of 'aliases' node and populate | ||
1032 | * the the global lookup table with the properties. It returns the | ||
1033 | * number of alias_prop found, or error code in error case. | ||
1034 | * | ||
1035 | * @dt_alloc: An allocator that provides a virtual address to memory | ||
1036 | * for the resulting tree | ||
1037 | */ | ||
1038 | void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align)) | ||
1039 | { | ||
1040 | struct property *pp; | ||
1041 | |||
1042 | of_chosen = of_find_node_by_path("/chosen"); | ||
1043 | if (of_chosen == NULL) | ||
1044 | of_chosen = of_find_node_by_path("/chosen@0"); | ||
1045 | of_aliases = of_find_node_by_path("/aliases"); | ||
1046 | if (!of_aliases) | ||
1047 | return; | ||
1048 | |||
1049 | for_each_property(pp, of_aliases->properties) { | ||
1050 | const char *start = pp->name; | ||
1051 | const char *end = start + strlen(start); | ||
1052 | struct device_node *np; | ||
1053 | struct alias_prop *ap; | ||
1054 | int id, len; | ||
1055 | |||
1056 | /* Skip those we do not want to proceed */ | ||
1057 | if (!strcmp(pp->name, "name") || | ||
1058 | !strcmp(pp->name, "phandle") || | ||
1059 | !strcmp(pp->name, "linux,phandle")) | ||
1060 | continue; | ||
1061 | |||
1062 | np = of_find_node_by_path(pp->value); | ||
1063 | if (!np) | ||
1064 | continue; | ||
1065 | |||
1066 | /* walk the alias backwards to extract the id and work out | ||
1067 | * the 'stem' string */ | ||
1068 | while (isdigit(*(end-1)) && end > start) | ||
1069 | end--; | ||
1070 | len = end - start; | ||
1071 | |||
1072 | if (kstrtoint(end, 10, &id) < 0) | ||
1073 | continue; | ||
1074 | |||
1075 | /* Allocate an alias_prop with enough space for the stem */ | ||
1076 | ap = dt_alloc(sizeof(*ap) + len + 1, 4); | ||
1077 | if (!ap) | ||
1078 | continue; | ||
1079 | ap->alias = start; | ||
1080 | of_alias_add(ap, np, id, start, len); | ||
1081 | } | ||
1082 | } | ||
1083 | |||
1084 | /** | ||
1085 | * of_alias_get_id - Get alias id for the given device_node | ||
1086 | * @np: Pointer to the given device_node | ||
1087 | * @stem: Alias stem of the given device_node | ||
1088 | * | ||
1089 | * The function travels the lookup table to get alias id for the given | ||
1090 | * device_node and alias stem. It returns the alias id if find it. | ||
1091 | */ | ||
1092 | int of_alias_get_id(struct device_node *np, const char *stem) | ||
1093 | { | ||
1094 | struct alias_prop *app; | ||
1095 | int id = -ENODEV; | ||
1096 | |||
1097 | mutex_lock(&of_aliases_mutex); | ||
1098 | list_for_each_entry(app, &aliases_lookup, link) { | ||
1099 | if (strcmp(app->stem, stem) != 0) | ||
1100 | continue; | ||
1101 | |||
1102 | if (np == app->np) { | ||
1103 | id = app->id; | ||
1104 | break; | ||
1105 | } | ||
1106 | } | ||
1107 | mutex_unlock(&of_aliases_mutex); | ||
1108 | |||
1109 | return id; | ||
1110 | } | ||
1111 | EXPORT_SYMBOL_GPL(of_alias_get_id); | ||