drm/nouveau/gr/gf100-: move fecs discover_zcull_image_size into a function

Makes the code somewhat less magic.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nvkm/engine/gr/gf100.c

@@ -715,6 +715,22 @@ gf100_gr_pack_mmio[] = {
  * PGRAPH engine/subdev functions
  ******************************************************************************/
 
+static int
+gf100_gr_fecs_discover_zcull_image_size(struct gf100_gr *gr, u32 *psize)
+{
+	struct nvkm_device *device = gr->base.engine.subdev.device;
+
+	nvkm_wr32(device, 0x409840, 0xffffffff);
+	nvkm_wr32(device, 0x409500, 0x00000000);
+	nvkm_wr32(device, 0x409504, 0x00000016);
+	nvkm_msec(device, 2000,
+		if ((*psize = nvkm_rd32(device, 0x409800)))
+			return 0;
+	);
+
+	return -ETIMEDOUT;
+}
+
 static int
 gf100_gr_fecs_discover_image_size(struct gf100_gr *gr, u32 *psize)
 {
@@ -1558,14 +1574,10 @@ gf100_gr_init_ctxctl_ext(struct gf100_gr *gr)
 	if (ret)
 		return ret;
 
-	nvkm_wr32(device, 0x409840, 0xffffffff);
-	nvkm_wr32(device, 0x409500, 0x00000000);
-	nvkm_wr32(device, 0x409504, 0x00000016);
-	if (nvkm_msec(device, 2000,
-		if (nvkm_rd32(device, 0x409800))
-			break;
-	) < 0)
-		return -EBUSY;
+	/* Determine how much memory is required to store ZCULL image. */
+	ret = gf100_gr_fecs_discover_zcull_image_size(gr, &gr->size_zcull);
+	if (ret)
+		return ret;
 
 	nvkm_wr32(device, 0x409840, 0xffffffff);
 	nvkm_wr32(device, 0x409500, 0x00000000);

drivers/gpu/drm/nouveau/nvkm/engine/gr/gf100.h

@@ -128,6 +128,7 @@ struct gf100_gr {
 	struct gf100_gr_mmio mmio_list[4096/8];
 	u32  size;
 	u32 *data;
+	u32 size_zcull;
 };
 
 int gf100_gr_ctor(const struct gf100_gr_func *, struct nvkm_device *,