[PATCH 6/7] gpu: drm: nova: build after nova-core metadata

[Alexandre Courbot]

Point rustc to `nova-core`'s `.rmeta` file so `nova-drm` can use
`nova_core`'s types and functions at compile time.

Signed-off-by: Alexandre Courbot <acourbot@xxxxxxxxxx>
---
 drivers/gpu/drm/nova/Makefile | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/gpu/drm/nova/Makefile b/drivers/gpu/drm/nova/Makefile
index 42019bff3173..f1d59c65120f 100644
--- a/drivers/gpu/drm/nova/Makefile
+++ b/drivers/gpu/drm/nova/Makefile
@@ -1,3 +1,18 @@
 # SPDX-License-Identifier: GPL-2.0
 
+nova_core_rmeta := drivers/gpu/nova-core/libnova_core.rmeta
+
+rustflags-y += --extern nova_core=$(objtree)/$(nova_core_rmeta)
+
+# `nova-drm` imports `nova-core` at compile time, so request `nova-core`'s
+# explicit metadata target before compiling nova.o.
+$(obj)/nova.o: | $(objtree)/$(nova_core_rmeta)
+
+# Build `nova-core`'s metadata by invoking make.
+#
+# This is ugly but only temporary until the build system natively supports
+# cross-crate dependencies.
+$(objtree)/$(nova_core_rmeta): FORCE
+	$(Q)$(MAKE) $(build)=drivers/gpu/nova-core $(nova_core_rmeta)
+
 obj-$(CONFIG_DRM_NOVA) += nova.o

-- 
2.54.0