drm/ttm: Documentation update

Remove an obsolete comment about mm nodes.
Document the new bo range manager interface.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index a1cb783c7131c56de8aa19cf5afb6a668e5e4345..cf47978cf0e21791ac7c2ab3f4dd09d35f1739d2 100644 (file)
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -27,14 +27,6 @@
 /*
  * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
  */
-/* Notes:
- *
- * We store bo pointer in drm_mm_node struct so we know which bo own a
- * specific node. There is no protection on the pointer, thus to make
- * sure things don't go berserk you have to access this pointer while
- * holding the global lru lock and make sure anytime you free a node you
- * reset the pointer to NULL.
- */
 
 #include "ttm/ttm_module.h"
 #include "ttm/ttm_bo_driver.h"

diff --git a/include/drm/ttm/ttm_bo_driver.h b/include/drm/ttm/ttm_bo_driver.h
index d01b4ddbdc56acb88fd1064b0e4580f82aa03b76..8e0c848326b6df5ccc95fc4ae16b965d81bfa0c8 100644 (file)
--- a/include/drm/ttm/ttm_bo_driver.h
+++ b/include/drm/ttm/ttm_bo_driver.h
@@ -206,14 +206,84 @@ struct ttm_tt {
 struct ttm_mem_type_manager;
 
 struct ttm_mem_type_manager_func {
+       /**
+        * struct ttm_mem_type_manager member init
+        *
+        * @man: Pointer to a memory type manager.
+        * @p_size: Implementation dependent, but typically the size of the
+        * range to be managed in pages.
+        *
+        * Called to initialize a private range manager. The function is
+        * expected to initialize the man::priv member.
+        * Returns 0 on success, negative error code on failure.
+        */
        int  (*init)(struct ttm_mem_type_manager *man, unsigned long p_size);
+
+       /**
+        * struct ttm_mem_type_manager member takedown
+        *
+        * @man: Pointer to a memory type manager.
+        *
+        * Called to undo the setup done in init. All allocated resources
+        * should be freed.
+        */
        int  (*takedown)(struct ttm_mem_type_manager *man);
+
+       /**
+        * struct ttm_mem_type_manager member get_node
+        *
+        * @man: Pointer to a memory type manager.
+        * @bo: Pointer to the buffer object we're allocating space for.
+        * @placement: Placement details.
+        * @mem: Pointer to a struct ttm_mem_reg to be filled in.
+        *
+        * This function should allocate space in the memory type managed
+        * by @man. Placement details if
+        * applicable are given by @placement. If successful,
+        * @mem::mm_node should be set to a non-null value, and
+        * @mem::start should be set to a value identifying the beginning
+        * of the range allocated, and the function should return zero.
+        * If the memory region accomodate the buffer object, @mem::mm_node
+        * should be set to NULL, and the function should return 0.
+        * If a system error occured, preventing the request to be fulfilled,
+        * the function should return a negative error code.
+        *
+        * Note that @mem::mm_node will only be dereferenced by
+        * struct ttm_mem_type_manager functions and optionally by the driver,
+        * which has knowledge of the underlying type.
+        *
+        * This function may not be called from within atomic context, so
+        * an implementation can and must use either a mutex or a spinlock to
+        * protect any data structures managing the space.
+        */
        int  (*get_node)(struct ttm_mem_type_manager *man,
                         struct ttm_buffer_object *bo,
                         struct ttm_placement *placement,
                         struct ttm_mem_reg *mem);
+
+       /**
+        * struct ttm_mem_type_manager member put_node
+        *
+        * @man: Pointer to a memory type manager.
+        * @mem: Pointer to a struct ttm_mem_reg to be filled in.
+        *
+        * This function frees memory type resources previously allocated
+        * and that are identified by @mem::mm_node and @mem::start. May not
+        * be called from within atomic context.
+        */
        void (*put_node)(struct ttm_mem_type_manager *man,
                         struct ttm_mem_reg *mem);
+
+       /**
+        * struct ttm_mem_type_manager member debug
+        *
+        * @man: Pointer to a memory type manager.
+        * @prefix: Prefix to be used in printout to identify the caller.
+        *
+        * This function is called to print out the state of the memory
+        * type manager to aid debugging of out-of-memory conditions.
+        * It may not be called from within atomic context.
+        */
        void (*debug)(struct ttm_mem_type_manager *man, const char *prefix);
 };
 
@@ -231,14 +301,13 @@ struct ttm_mem_type_manager {
        uint64_t size;
        uint32_t available_caching;
        uint32_t default_caching;
+       const struct ttm_mem_type_manager_func *func;
+       void *priv;
 
        /*
-        * Protected by the bdev->lru_lock.
-        * TODO: Consider one lru_lock per ttm_mem_type_manager.
-        * Plays ill with list removal, though.
+        * Protected by the global->lru_lock.
         */
-       const struct ttm_mem_type_manager_func *func;
-       void *priv;
+
        struct list_head lru;
 };