[PATCH] docs: Integrate rustdoc-generated output to Rust docs

[Carlos Bilbao <carlos.bilbao@amd.com>]

Include HTML output generated from rustdoc into the Linux kernel
documentation on Rust. Add Makefile target `make htmlrust` to combine
make htmldocs and the generation of Rust documentation.

Signed-off-by: Carlos Bilbao <carlos.bilbao@amd.com>
---
 Documentation/Makefile         | 11 +++++++++++
 Documentation/rust/index.rst   |  1 +
 Documentation/rust/rustdoc.rst | 10 ++++++++++
 Makefile                       |  2 +-
 4 files changed, 23 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/rust/rustdoc.rst

diff --git a/Documentation/Makefile b/Documentation/Makefile
index 64d44c1ecad3..02ed01fa3499 100644
--- a/Documentation/Makefile
+++ b/Documentation/Makefile
@@ -95,6 +95,17 @@ htmldocs:
 	@$(srctree)/scripts/sphinx-pre-install --version-check
 	@+$(foreach var,$(SPHINXDIRS),$(call loop_cmd,sphinx,html,$(var),,$(var)))
 
+ifdef CONFIG_RUST
+htmlrust:
+	@make rustavailable
+	@make LLVM=1 rustdoc
+	@cp -r rust/doc/* Documentation/output/
+	@make htmldocs
+else
+htmlrust:
+	@echo "Error: CONFIG_RUST must be defined (see .config)"
+endif
+
 linkcheckdocs:
 	@$(foreach var,$(SPHINXDIRS),$(call loop_cmd,sphinx,linkcheck,$(var),,$(var)))
 
diff --git a/Documentation/rust/index.rst b/Documentation/rust/index.rst
index 4ae8c66b94fa..5e7a9d39af90 100644
--- a/Documentation/rust/index.rst
+++ b/Documentation/rust/index.rst
@@ -13,6 +13,7 @@ in the kernel, please read the quick-start.rst guide.
     general-information
     coding-guidelines
     arch-support
+    rustdoc
 
 .. only::  subproject and html
 
diff --git a/Documentation/rust/rustdoc.rst b/Documentation/rust/rustdoc.rst
new file mode 100644
index 000000000000..74581367417b
--- /dev/null
+++ b/Documentation/rust/rustdoc.rst
@@ -0,0 +1,10 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Rustdoc output
+==============
+
+If this documentation includes rustdoc-generated HTML, this is the
+entry point.
+
+.. raw:: html
+    :file: doc/kernel/index.html
diff --git a/Makefile b/Makefile
index f41ec8c8426b..c7e00bf928ed 100644
--- a/Makefile
+++ b/Makefile
@@ -1785,7 +1785,7 @@ $(help-board-dirs): help-%:
 # Documentation targets
 # ---------------------------------------------------------------------------
 DOC_TARGETS := xmldocs latexdocs pdfdocs htmldocs epubdocs cleandocs \
-	       linkcheckdocs dochelp refcheckdocs
+	       linkcheckdocs dochelp refcheckdocs htmlrust
 PHONY += $(DOC_TARGETS)
 $(DOC_TARGETS):
 	$(Q)$(MAKE) $(build)=Documentation $@
-- 
2.34.1