[PATCH v2 02/37] linker_lists: Allow use in data structures

[Simon Glass]

At present linker lists are designed for use in code. They make use of
statements within expressions ({...}), for example.

It is possible to generate a reference to a linker_list entry that can
be used in data structures, where such features are not permitted. It
requires that the reference first be declared as extern. In other
words the existing macro needs to be split into two parts.

Add new macros to support this.

Signed-off-by: Simon Glass <sjg at chromium.org>
---

(no changes since v1)

 include/linker_lists.h | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/include/linker_lists.h b/include/linker_lists.h
index fd98ecd297c..55631f0240c 100644
--- a/include/linker_lists.h
+++ b/include/linker_lists.h
@@ -211,6 +211,34 @@
 		_ll_result;						\
 	})
 
+/**
+ * ll_entry_decl() - Declare a linker-generated array entry reference as extern
+ *
+ * This declares a reference to a list entry so that it can be used later,
+ * without needing the code in ll_entry_get().
+ *
+ * To use this, put ll_entry_decl() somewhere in your file, then use
+ * ll_entry_ref() later on, to reference the entry.
+ *
+ * @_type:	Data type of the entry
+ * @_name:	Name of the entry
+ * @_list:	Name of the list in which this entry is placed
+ */
+#define ll_entry_decl(_type, _name, _list)				\
+	extern _type _u_boot_list_2_##_list##_2_##_name
+
+/**
+ * ll_entry_ref() - Get a reference to a linker-generated array entry
+ *
+ * Once ll_entry_decl() has been used to declare the reference, this macro
+ * allows the entry to be accessed.
+ *
+ * This is like ll_entry_get(), but without the extra code, so it is suitable
+ * for putting into data structures.
+ */
+#define ll_entry_ref(_type, _name, _list)				\
+	((_type *)&_u_boot_list_2_##_list##_2_##_name)
+
 /**
  * ll_start() - Point to first entry of first linker-generated array
  * @_type:	Data type of the entry
-- 
2.30.0.365.g02bc693789-goog