drm/i915/uapi: convert i915_user_extension to kernel doc

[linux-2.6-microblaze.git] / include / uapi / drm / i915_drm.h

diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index 92da48e..e2867d8 100644 (file)
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -62,8 +62,8 @@ extern "C" {
 #define I915_ERROR_UEVENT              "ERROR"
 #define I915_RESET_UEVENT              "RESET"
 
-/*
- * i915_user_extension: Base class for defining a chain of extensions
+/**
+ * struct i915_user_extension - Base class for defining a chain of extensions
  *
  * Many interfaces need to grow over time. In most cases we can simply
  * extend the struct and have userspace pass in more data. Another option,
@@ -76,12 +76,58 @@ extern "C" {
  * increasing complexity, and for large parts of that interface to be
  * entirely optional. The downside is more pointer chasing; chasing across
  * the __user boundary with pointers encapsulated inside u64.
+ *
+ * Example chaining:
+ *
+ * .. code-block:: C
+ *
+ *     struct i915_user_extension ext3 {
+ *             .next_extension = 0, // end
+ *             .name = ...,
+ *     };
+ *     struct i915_user_extension ext2 {
+ *             .next_extension = (uintptr_t)&ext3,
+ *             .name = ...,
+ *     };
+ *     struct i915_user_extension ext1 {
+ *             .next_extension = (uintptr_t)&ext2,
+ *             .name = ...,
+ *     };
+ *
+ * Typically the struct i915_user_extension would be embedded in some uAPI
+ * struct, and in this case we would feed it the head of the chain(i.e ext1),
+ * which would then apply all of the above extensions.
+ *
  */
 struct i915_user_extension {
+       /**
+        * @next_extension:
+        *
+        * Pointer to the next struct i915_user_extension, or zero if the end.
+        */
        __u64 next_extension;
+       /**
+        * @name: Name of the extension.
+        *
+        * Note that the name here is just some integer.
+        *
+        * Also note that the name space for this is not global for the whole
+        * driver, but rather its scope/meaning is limited to the specific piece
+        * of uAPI which has embedded the struct i915_user_extension.
+        */
        __u32 name;
-       __u32 flags; /* All undefined bits must be zero. */
-       __u32 rsvd[4]; /* Reserved for future use; must be zero. */
+       /**
+        * @flags: MBZ
+        *
+        * All undefined bits must be zero.
+        */
+       __u32 flags;
+       /**
+        * @rsvd: MBZ
+        *
+        * Reserved for future use; must be zero.
+        */
+       __u32 rsvd[4];
 };
 
 /*