nouveau: Add CPU push buffers

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/24326>

src/nouveau/winsys/nouveau_push.c

@@ -62,12 +62,41 @@ fail_bo:
    return NULL;
 }
 
+void
+nouveau_ws_push_init_cpu(struct nouveau_ws_push *push,
+                         void *data, size_t size)
+{
+   push->map = data;
+   push->orig_map = push->map;
+   push->end = push->map + size;
+
+   util_dynarray_init(&push->bos, NULL);
+}
+
 void
 nouveau_ws_push_destroy(struct nouveau_ws_push *push)
 {
    util_dynarray_fini(&push->bos);
-   munmap(push->orig_map, push->bo->size);
-   nouveau_ws_bo_destroy(push->bo);
+   if (push->bo) {
+      munmap(push->orig_map, push->bo->size);
+      nouveau_ws_bo_destroy(push->bo);
+   }
+}
+
+void
+nouveau_ws_push_append(struct nouveau_ws_push *push,
+                       const struct nouveau_ws_push *other)
+{
+   /* We only use this for CPU pushes. */
+   assert(other->bo == NULL);
+
+   /* We don't support BO refs for now */
+   assert(other->bos.size == 0);
+
+   size_t count = other->map - other->orig_map;
+   memcpy(push->map, other->orig_map, count * sizeof(*push->map));
+   push->map += count;
+   push->last_size = NULL;
 }
 
 static void
@@ -249,6 +278,9 @@ nouveau_ws_push_submit(
    struct drm_nouveau_gem_pushbuf req = {};
    struct drm_nouveau_gem_pushbuf_push req_push = {};
 
+   /* Can't submit a CPU push */
+   assert(push->bo);
+
    if (push->map == push->orig_map)
       return 0;
 

src/nouveau/winsys/nouveau_push.h

@@ -25,7 +25,11 @@ struct nouveau_ws_push {
 };
 
 struct nouveau_ws_push *nouveau_ws_push_new(struct nouveau_ws_device *, uint64_t size);
+void nouveau_ws_push_init_cpu(struct nouveau_ws_push *push,
+                              void *data, size_t size);
 void nouveau_ws_push_destroy(struct nouveau_ws_push *);
+void nouveau_ws_push_append(struct nouveau_ws_push *,
+                            const struct nouveau_ws_push *);
 int nouveau_ws_push_submit(struct nouveau_ws_push *, struct nouveau_ws_device *, struct nouveau_ws_context *);
 void nouveau_ws_push_ref(struct nouveau_ws_push *, struct nouveau_ws_bo *, enum nouveau_ws_bo_map_flags);
 void nouveau_ws_push_reset(struct nouveau_ws_push *);