of: Output devicetree alias names in uevent

In some situations, userspace may want to resolve a device by function and logical number (ie, "serial0") rather than by the base address or full device path. Being able to resolve a device by alias frees userspace from the burden of otherwise having to maintain a mapping between device addresses and their logical assignments on each platform when multiple instances of the same hardware block are present in the system. Although the uevent device attribute contains devicetree compatible information and the full device path, the uevent does not list the alises that may have been defined for the device. Signed-off-by: Stepan Moskovchenko <stepanm@codeaurora.org> [grant.likely: Removed OF_ALIAS_N field; I don't think it's needed] [grant.likely: Added #ifndef _LINUX_OF_PRIVATE_H wrapper] Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

of: Output devicetree alias names in uevent
In some situations, userspace may want to resolve a device by function and logical number (ie, "serial0") rather than by the base address or full device path. Being able to resolve a device by alias frees userspace from the burden of otherwise having to maintain a mapping between device addresses and their logical assignments on each platform when multiple instances of the same hardware block are present in the system. Although the uevent device attribute contains devicetree compatible information and the full device path, the uevent does not list the alises that may have been defined for the device. Signed-off-by: Stepan Moskovchenko <stepanm@codeaurora.org> [grant.likely: Removed OF_ALIAS_N field; I don't think it's needed] [grant.likely: Added #ifndef _LINUX_OF_PRIVATE_H wrapper] Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Stepan Moskovchenko · Grant Likely
1 parent 88b62b915b
Showing 3 changed files with 52 additions and 20 deletions Side-by-side Diff
drivers/of/base.c
drivers/of/device.c
drivers/of/of_private.h
@@ -24,33 +24,16 @@
 #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];
-};
+#include "of_private.h"
  
-static LIST_HEAD(aliases_lookup);
+LIST_HEAD(aliases_lookup);
  
 struct device_node *of_allnodes;
 EXPORT_SYMBOL(of_allnodes);
 struct device_node *of_chosen;
 struct device_node *of_aliases;
  
-static DEFINE_MUTEX(of_aliases_mutex);
+DEFINE_MUTEX(of_aliases_mutex);
  
 /* use when traversing tree through the allnext, child, sibling,
  * or parent members of struct device_node.
@@ -8,6 +8,7 @@
 #include <linux/slab.h>
  
 #include <asm/errno.h>
+#include "of_private.h"
  
 /**
  * of_match_device - Tell if a struct device matches an of_device_id list
@@ -131,6 +132,7 @@
 void of_device_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
 	const char *compat;
+	struct alias_prop *app;
 	int seen = 0, cplen, sl;
  
 	if ((!dev) || (!dev->of_node))
@@ -153,6 +155,17 @@
 		seen++;
 	}
 	add_uevent_var(env, "OF_COMPATIBLE_N=%d", seen);
+
+	seen = 0;
+	mutex_lock(&of_aliases_mutex);
+	list_for_each_entry(app, &aliases_lookup, link) {
+		if (dev->of_node == app->np) {
+			add_uevent_var(env, "OF_ALIAS_%d=%s", seen,
+				       app->alias);
+			seen++;
+		}
+	}
+	mutex_unlock(&of_aliases_mutex);
 }
  
 int of_device_uevent_modalias(struct device *dev, struct kobj_uevent_env *env)
+#ifndef _LINUX_OF_PRIVATE_H
+#define _LINUX_OF_PRIVATE_H
+/*
+ * Private symbols used by OF support code
+ *
+ * Paul Mackerras	August 1996.
+ * Copyright (C) 1996-2005 Paul Mackerras.
+ *
+ * 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.
+ */
+
+/**
+ * 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];
+};
+
+extern struct mutex of_aliases_mutex;
+extern struct list_head aliases_lookup;
+#endif /* _LINUX_OF_PRIVATE_H */
...	...	@@ -24,33 +24,16 @@
24	24	#include <linux/slab.h>
25	25	#include <linux/proc_fs.h>
26	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		-};
	27	+#include "of_private.h"
45	28
46		-static LIST_HEAD(aliases_lookup);
	29	+LIST_HEAD(aliases_lookup);
47	30
48	31	struct device_node *of_allnodes;
49	32	EXPORT_SYMBOL(of_allnodes);
50	33	struct device_node *of_chosen;
51	34	struct device_node *of_aliases;
52	35
53		-static DEFINE_MUTEX(of_aliases_mutex);
	36	+DEFINE_MUTEX(of_aliases_mutex);
54	37
55	38	/* use when traversing tree through the allnext, child, sibling,
56	39	* or parent members of struct device_node.
...	...	@@ -8,6 +8,7 @@
8	8	#include <linux/slab.h>
9	9
10	10	#include <asm/errno.h>
	11	+#include "of_private.h"
11	12
12	13	/**
13	14	* of_match_device - Tell if a struct device matches an of_device_id list
...	...	@@ -131,6 +132,7 @@
131	132	void of_device_uevent(struct device dev, struct kobj_uevent_env env)
132	133	{
133	134	const char *compat;
	135	+ struct alias_prop *app;
134	136	int seen = 0, cplen, sl;
135	137
136	138	if ((!dev) \|\| (!dev->of_node))
...	...	@@ -153,6 +155,17 @@
153	155	seen++;
154	156	}
155	157	add_uevent_var(env, "OF_COMPATIBLE_N=%d", seen);
	158	+
	159	+ seen = 0;
	160	+ mutex_lock(&of_aliases_mutex);
	161	+ list_for_each_entry(app, &aliases_lookup, link) {
	162	+ if (dev->of_node == app->np) {
	163	+ add_uevent_var(env, "OF_ALIAS_%d=%s", seen,
	164	+ app->alias);
	165	+ seen++;
	166	+ }
	167	+ }
	168	+ mutex_unlock(&of_aliases_mutex);
156	169	}
157	170
158	171	int of_device_uevent_modalias(struct device dev, struct kobj_uevent_env env)
	1	+#ifndef _LINUX_OF_PRIVATE_H
	2	+#define _LINUX_OF_PRIVATE_H
	3	+/*
	4	+ * Private symbols used by OF support code
	5	+ *
	6	+ * Paul Mackerras August 1996.
	7	+ * Copyright (C) 1996-2005 Paul Mackerras.
	8	+ *
	9	+ * This program is free software; you can redistribute it and/or
	10	+ * modify it under the terms of the GNU General Public License
	11	+ * as published by the Free Software Foundation; either version
	12	+ * 2 of the License, or (at your option) any later version.
	13	+ */
	14	+
	15	+/**
	16	+ * struct alias_prop - Alias property in 'aliases' node
	17	+ * @link: List node to link the structure in aliases_lookup list
	18	+ * @alias: Alias property name
	19	+ * @np: Pointer to device_node that the alias stands for
	20	+ * @id: Index value from end of alias name
	21	+ * @stem: Alias string without the index
	22	+ *
	23	+ * The structure represents one alias property of 'aliases' node as
	24	+ * an entry in aliases_lookup list.
	25	+ */
	26	+struct alias_prop {
	27	+ struct list_head link;
	28	+ const char *alias;
	29	+ struct device_node *np;
	30	+ int id;
	31	+ char stem[0];
	32	+};
	33	+
	34	+extern struct mutex of_aliases_mutex;
	35	+extern struct list_head aliases_lookup;
	36	+#endif /* _LINUX_OF_PRIVATE_H */