drm/doc: Add function reference documentation for drm_mm.c

While at it do a tiny bit of interface cleanup and convert boolean
return values to bool. With this patch all exported functions and inline
helpers which are part of the drm_mm public interface are documented.

Also drop superflous extern function modifiers since most of drm_mm.h
doesn't use them - more consistent that way.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 125 insertions, 29 deletions

diff --git a/include/drm/drm_mm.h b/include/drm/drm_mm.h
index cba67865d18..8b6981ab3fc 100644
--- a/include/drm/drm_mm.h
+++ b/include/drm/drm_mm.h
@@ -85,11 +85,31 @@ struct drm_mm {
 			     unsigned long *start, unsigned long *end);
 };
 
+/**
+ * drm_mm_node_allocated - checks whether a node is allocated
+ * @node: drm_mm_node to check
+ *
+ * Drivers should use this helpers for proper encapusulation of drm_mm
+ * internals.
+ *
+ * Returns:
+ * True if the @node is allocated.
+ */
 static inline bool drm_mm_node_allocated(struct drm_mm_node *node)
 {
 	return node->allocated;
 }
 
+/**
+ * drm_mm_initialized - checks whether an allocator is initialized
+ * @mm: drm_mm to check
+ *
+ * Drivers should use this helpers for proper encapusulation of drm_mm
+ * internals.
+ *
+ * Returns:
+ * True if the @mm is initialized.
+ */
 static inline bool drm_mm_initialized(struct drm_mm *mm)
 {
 	return mm->hole_stack.next;
@@ -100,6 +120,17 @@ static inline unsigned long __drm_mm_hole_node_start(struct drm_mm_node *hole_no
 	return hole_node->start + hole_node->size;
 }
 
+/**
+ * drm_mm_hole_node_start - computes the start of the hole following @node
+ * @hole_node: drm_mm_node which implicitly tracks the following hole
+ *
+ * This is useful for driver-sepific debug dumpers. Otherwise drivers should not
+ * inspect holes themselves. Drivers must check first whether a hole indeed
+ * follows by looking at node->hole_follows.
+ *
+ * Returns:
+ * Start of the subsequent hole.
+ */
 static inline unsigned long drm_mm_hole_node_start(struct drm_mm_node *hole_node)
 {
 	BUG_ON(!hole_node->hole_follows);
@@ -112,18 +143,49 @@ static inline unsigned long __drm_mm_hole_node_end(struct drm_mm_node *hole_node
 			  struct drm_mm_node, node_list)->start;
 }
 
+/**
+ * drm_mm_hole_node_end - computes the end of the hole following @node
+ * @hole_node: drm_mm_node which implicitly tracks the following hole
+ *
+ * This is useful for driver-sepific debug dumpers. Otherwise drivers should not
+ * inspect holes themselves. Drivers must check first whether a hole indeed
+ * follows by looking at node->hole_follows.
+ *
+ * Returns:
+ * End of the subsequent hole.
+ */
 static inline unsigned long drm_mm_hole_node_end(struct drm_mm_node *hole_node)
 {
 	return __drm_mm_hole_node_end(hole_node);
 }
 
+/**
+ * drm_mm_for_each_node - iterator to walk over all allocated nodes
+ * @entry: drm_mm_node structure to assign to in each iteration step
+ * @mm: drm_mm allocator to walk
+ *
+ * This iterator walks over all nodes in the range allocator. It is implemented
+ * with list_for_each, so not save against removal of elements.
+ */
 #define drm_mm_for_each_node(entry, mm) list_for_each_entry(entry, \
 						&(mm)->head_node.node_list, \
 						node_list)
 
-/* Note that we need to unroll list_for_each_entry in order to inline
- * setting hole_start and hole_end on each iteration and keep the
- * macro sane.
+/**
+ * drm_mm_for_each_hole - iterator to walk over all holes
+ * @entry: drm_mm_node used internally to track progress
+ * @mm: drm_mm allocator to walk
+ * @hole_start: ulong variable to assign the hole start to on each iteration
+ * @hole_end: ulong variable to assign the hole end to on each iteration
+ *
+ * This iterator walks over all holes in the range allocator. It is implemented
+ * with list_for_each, so not save against removal of elements. @entry is used
+ * internally and will not reflect a real drm_mm_node for the very first hole.
+ * Hence users of this iterator may not access it.
+ *
+ * Implementation Note:
+ * We need to inline list_for_each_entry in order to be able to set hole_start
+ * and hole_end on each iteration while keeping the macro sane.
  */
 #define drm_mm_for_each_hole(entry, mm, hole_start, hole_end) \
 	for (entry = list_entry((mm)->hole_stack.next, struct drm_mm_node, hole_stack); \
@@ -136,14 +198,30 @@ static inline unsigned long drm_mm_hole_node_end(struct drm_mm_node *hole_node)
 /*
  * Basic range manager support (drm_mm.c)
  */
-extern int drm_mm_reserve_node(struct drm_mm *mm, struct drm_mm_node *node);
-
-extern int drm_mm_insert_node_generic(struct drm_mm *mm,
-				      struct drm_mm_node *node,
-				      unsigned long size,
-				      unsigned alignment,
-				      unsigned long color,
-				      enum drm_mm_search_flags flags);
+int drm_mm_reserve_node(struct drm_mm *mm, struct drm_mm_node *node);
+
+int drm_mm_insert_node_generic(struct drm_mm *mm,
+			       struct drm_mm_node *node,
+			       unsigned long size,
+			       unsigned alignment,
+			       unsigned long color,
+			       enum drm_mm_search_flags flags);
+/**
+ * drm_mm_insert_node - search for space and insert @node
+ * @mm: drm_mm to allocate from
+ * @node: preallocate node to insert
+ * @size: size of the allocation
+ * @alignment: alignment of the allocation
+ * @flags: flags to fine-tune the allocation
+ *
+ * This is a simplified version of drm_mm_insert_node_generic() with @color set
+ * to 0.
+ *
+ * The preallocated node must be cleared to 0.
+ *
+ * Returns:
+ * 0 on success, -ENOSPC if there's no suitable hole.
+ */
 static inline int drm_mm_insert_node(struct drm_mm *mm,
 				     struct drm_mm_node *node,
 				     unsigned long size,
@@ -153,14 +231,32 @@ static inline int drm_mm_insert_node(struct drm_mm *mm,
 	return drm_mm_insert_node_generic(mm, node, size, alignment, 0, flags);
 }
 
-extern int drm_mm_insert_node_in_range_generic(struct drm_mm *mm,
-				       struct drm_mm_node *node,
-				       unsigned long size,
-				       unsigned alignment,
-				       unsigned long color,
-				       unsigned long start,
-				       unsigned long end,
-				       enum drm_mm_search_flags flags);
+int drm_mm_insert_node_in_range_generic(struct drm_mm *mm,
+					struct drm_mm_node *node,
+					unsigned long size,
+					unsigned alignment,
+					unsigned long color,
+					unsigned long start,
+					unsigned long end,
+					enum drm_mm_search_flags flags);
+/**
+ * drm_mm_insert_node_in_range - ranged search for space and insert @node
+ * @mm: drm_mm to allocate from
+ * @node: preallocate node to insert
+ * @size: size of the allocation
+ * @alignment: alignment of the allocation
+ * @start: start of the allowed range for this node
+ * @end: end of the allowed range for this node
+ * @flags: flags to fine-tune the allocation
+ *
+ * This is a simplified version of drm_mm_insert_node_in_range_generic() with
+ * @color set to 0.
+ *
+ * The preallocated node must be cleared to 0.
+ *
+ * Returns:
+ * 0 on success, -ENOSPC if there's no suitable hole.
+ */
 static inline int drm_mm_insert_node_in_range(struct drm_mm *mm,
 					      struct drm_mm_node *node,
 					      unsigned long size,
@@ -173,13 +269,13 @@ static inline int drm_mm_insert_node_in_range(struct drm_mm *mm,
 						   0, start, end, flags);
 }
 
-extern void drm_mm_remove_node(struct drm_mm_node *node);
-extern void drm_mm_replace_node(struct drm_mm_node *old, struct drm_mm_node *new);
-extern void drm_mm_init(struct drm_mm *mm,
-			unsigned long start,
-			unsigned long size);
-extern void drm_mm_takedown(struct drm_mm *mm);
-extern int drm_mm_clean(struct drm_mm *mm);
+void drm_mm_remove_node(struct drm_mm_node *node);
+void drm_mm_replace_node(struct drm_mm_node *old, struct drm_mm_node *new);
+void drm_mm_init(struct drm_mm *mm,
+		 unsigned long start,
+		 unsigned long size);
+void drm_mm_takedown(struct drm_mm *mm);
+bool drm_mm_clean(struct drm_mm *mm);
 
 void drm_mm_init_scan(struct drm_mm *mm,
 		      unsigned long size,
@@ -191,10 +287,10 @@ void drm_mm_init_scan_with_range(struct drm_mm *mm,
 				 unsigned long color,
 				 unsigned long start,
 				 unsigned long end);
-int drm_mm_scan_add_block(struct drm_mm_node *node);
-int drm_mm_scan_remove_block(struct drm_mm_node *node);
+bool drm_mm_scan_add_block(struct drm_mm_node *node);
+bool drm_mm_scan_remove_block(struct drm_mm_node *node);
 
-extern void drm_mm_debug_table(struct drm_mm *mm, const char *prefix);
+void drm_mm_debug_table(struct drm_mm *mm, const char *prefix);
 #ifdef CONFIG_DEBUG_FS
 int drm_mm_dump_table(struct seq_file *m, struct drm_mm *mm);
 #endif