From a1704be974e216b40cd40449989c688d079b1cc6 Mon Sep 17 00:00:00 2001
From: Marcin Radomski <dextero@google.com>
Date: Tue, 5 Mar 2024 11:00:10 +0000
Subject: libdrm: add bindgen-generated Rust bindings

This provides the bindings necessary to use the Rust drm crate within
Android source tree. Bindgen flags used in the rust_bindgen definition,
as well as the workaround described in wrapper.h were based on drm-ffi
crate's build.rs [1].

Looking at other rust_bindgen modules, they are generally defined
alongside the native module they provide bindings to.

Details: go/drm-gbm-rust-crates-for-android

[1] https://github.com/Smithay/drm-rs/blob/328742fddc675b3370057b382eb54acbc9b48c79/drm-ffi/drm-sys/build.rs#L126

Bug: 328178122
Test: lunch aosp_cf_x86_64_only_phone-trunk_staging-userdebug && m
Test: m libdrm_sys
Change-Id: I18ea318dcd4a0734d647fe7a703e8c3ab7442a52
---
 Android.bp         | 61 ++++++++++++++++++++++++++++++++++++++++++++++++++----
 rust/drm_wrapper.h | 22 ++++++++++++++++++++
 2 files changed, 79 insertions(+), 4 deletions(-)
 create mode 100644 rust/drm_wrapper.h

diff --git a/Android.bp b/Android.bp
index 7ed9174e..ea471952 100644
--- a/Android.bp
+++ b/Android.bp
@@ -81,7 +81,10 @@ cc_library_headers {
     vendor_available: true,
     host_supported: true,
     defaults: ["libdrm_defaults"],
-    export_include_dirs: ["include/drm", "android"],
+    export_include_dirs: [
+        "include/drm",
+        "android",
+    ],
     apex_available: [
         "//apex_available:platform",
         "com.android.virt",
@@ -92,14 +95,22 @@ cc_library_headers {
 cc_library {
     name: "libdrm",
     recovery_available: true,
-    vendor_available: true,
     host_supported: true,
+    vendor_available: true,
+    product_available: true,
+    apex_available: [
+        "//apex_available:platform",
+        "//apex_available:anyapex",
+    ],
     defaults: [
         "libdrm_defaults",
         "libdrm_sources",
     ],
 
-    export_include_dirs: ["include/drm", "android"],
+    export_include_dirs: [
+        "include/drm",
+        "android",
+    ],
 
     cflags: [
         "-Wno-enum-conversion",
@@ -107,8 +118,50 @@ cc_library {
         "-Wno-sign-compare",
         "-Wno-tautological-compare",
     ],
+}
+
+// Rust bindings for libdrm, generated in a way compatible with drm-ffi crate.
+rust_bindgen {
+    name: "libdrm_sys",
+    crate_name: "drm_sys",
+    wrapper_src: "rust/drm_wrapper.h",
+    source_stem: "bindings",
+    bindgen_flags: [
+        "--ctypes-prefix=core::ffi",
+        "--no-prepend-enum-name",
+        "--with-derive-default",
+        "--with-derive-hash",
+        "--with-derive-eq",
+        "--blocklist-type=drm_handle_t",
+        "--blocklist-type=__BINDGEN_TMP_.*",
+        "--blocklist-type=drm_control_DRM_ADD_COMMAND",
+        "--allowlist-type=_?DRM_.*|drm_.*|hdr_.*",
+        "--allowlist-var=_?DRM_.*|drm_.*",
+        "--constified-enum-module=drm_control_.*",
+        "--constified-enum-module=drm_buf_desc_.*",
+        "--constified-enum-module=drm_map_type",
+        "--constified-enum-module=drm_map_flags",
+        "--constified-enum-module=drm_stat_type",
+        "--constified-enum-module=drm_lock_flags",
+        "--constified-enum-module=drm_dma_flags",
+        "--constified-enum-module=drm_ctx_flags",
+        "--constified-enum-module=drm_drawable_info_type_t",
+        "--constified-enum-module=drm_vblank_seq_type",
+        "--constified-enum-module=drm_mode_subconnector",
+    ],
+    shared_libs: [
+        "libdrm",
+        "libcutils",
+        "liblog",
+    ],
+    host_supported: true,
+    vendor_available: true,
+    product_available: true,
     apex_available: [
+        "//apex_available:anyapex",
         "//apex_available:platform",
-        "com.android.virt",
+    ],
+    visibility: [
+        "//external/rust/crates/drm-ffi",
     ],
 }
diff --git a/rust/drm_wrapper.h b/rust/drm_wrapper.h
new file mode 100644
index 00000000..98d877e1
--- /dev/null
+++ b/rust/drm_wrapper.h
@@ -0,0 +1,22 @@
+/*
+ * Copyright 2024 Google LLC
+ */
+
+#include <fcntl.h>
+#include <xf86drm.h>
+#include <xf86drmMode.h>
+
+// bindgen doesn't create constants for macros that expand to other macros
+// https://github.com/Smithay/drm-rs/blob/328742fddc675b3370057b382eb54acbc9b48c79/drm-ffi/drm-sys/build.rs#L110
+
+const unsigned int __BINDGEN_TMP_DRM_MODE_PROP_OBJECT = DRM_MODE_PROP_OBJECT;
+#undef DRM_MODE_PROP_OBJECT
+const unsigned int DRM_MODE_PROP_OBJECT = __BINDGEN_TMP_DRM_MODE_PROP_OBJECT;
+#define DRM_MODE_PROP_OBJECT DRM_MODE_PROP_OBJECT
+
+const unsigned int __BINDGEN_TMP_DRM_MODE_PROP_SIGNED_RANGE =
+    DRM_MODE_PROP_SIGNED_RANGE;
+#undef DRM_MODE_PROP_SIGNED_RANGE
+const unsigned int DRM_MODE_PROP_SIGNED_RANGE =
+    __BINDGEN_TMP_DRM_MODE_PROP_SIGNED_RANGE;
+#define DRM_MODE_PROP_SIGNED_RANGE DRM_MODE_PROP_SIGNED_RANGE
-- 
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