build.sh: Add INITRAMFS_VENDOR_RAMDISK_FRAGMENT_NAME

Add option to package kernel modules initramfs as a standalone ramdisk
fragment. Useful for testing as the entire set of kernel modules can be
replaced by post-processing.

Bug: 184490452
Test: Set INITRAMFS_VENDOR_RAMDISK_FRAGMENT_NAME and
  INITRAMFS_VENDOR_RAMDISK_FRAGMENT_MKBOOTIMG_ARGS and build
Test: Presubmit
Change-Id: I76d20e4afc1888c09adc257adab3ff7c4cc2c868

1 files changed, 25 insertions, 4 deletions

diff --git a/build.sh b/build.sh
index d5907dcf..4aed58e2 100755
--- a/build.sh
+++ b/build.sh
@@ -214,6 +214,11 @@
 #       blocklist module_name
 #     If BOOT_IMAGE_HEADER_VERSION >= 4, the following variable can be defined:
 #     - VENDOR_BOOTCONFIG=<string of bootconfig parameters>
+#     - INITRAMFS_VENDOR_RAMDISK_FRAGMENT_NAME=<name of the ramdisk fragment>
+#       If BUILD_INITRAMFS is specified, then build the .ko and depmod files as
+#       a standalone vendor ramdisk fragment named as the given string.
+#     - INITRAMFS_VENDOR_RAMDISK_FRAGMENT_MKBOOTIMG_ARGS=<mkbootimg arguments>
+#       Refer to: https://source.android.com/devices/bootloader/partitions/vendor-boot-partitions#mkbootimg-arguments
 #
 #   VENDOR_RAMDISK_CMDS
 #     When building vendor boot image, VENDOR_RAMDISK_CMDS enables the build
@@ -1116,22 +1121,29 @@ if [ ! -z "${BUILD_BOOT_IMG}" ] ; then
     cp "${VENDOR_FSTAB}" "${MKBOOTIMG_RAMDISK_STAGING_DIR}/first_stage_ramdisk/"
   fi
 
+  HAS_RAMDISK=
   MKBOOTIMG_RAMDISK_DIRS=()
   if [ -f "${VENDOR_RAMDISK_BINARY}" ] || [ -f "${VENDOR_FSTAB}" ]; then
+    HAS_RAMDISK="1"
     MKBOOTIMG_RAMDISK_DIRS+=("${MKBOOTIMG_RAMDISK_STAGING_DIR}")
   fi
 
   if [ "${BUILD_INITRAMFS}" = "1" ]; then
-    MKBOOTIMG_RAMDISK_DIRS+=("${INITRAMFS_STAGING_DIR}")
+    HAS_RAMDISK="1"
+    if [ -z "${INITRAMFS_VENDOR_RAMDISK_FRAGMENT_NAME}" ]; then
+      MKBOOTIMG_RAMDISK_DIRS+=("${INITRAMFS_STAGING_DIR}")
+    fi
+  fi
+
+  if [ -z "${HAS_RAMDISK}" ] && [ -z "${SKIP_VENDOR_BOOT}" ]; then
+    echo "No ramdisk found. Please provide a GKI and/or a vendor ramdisk."
+    exit 1
   fi
 
   if [ "${#MKBOOTIMG_RAMDISK_DIRS[@]}" -gt 0 ]; then
     MKBOOTIMG_RAMDISK_CPIO="${MKBOOTIMG_STAGING_DIR}/ramdisk.cpio"
     mkbootfs "${MKBOOTIMG_RAMDISK_DIRS[@]}" >"${MKBOOTIMG_RAMDISK_CPIO}"
     ${RAMDISK_COMPRESS} "${MKBOOTIMG_RAMDISK_CPIO}" >"${DIST_DIR}/ramdisk.${RAMDISK_EXT}"
-  elif [ -z "${SKIP_VENDOR_BOOT}" ]; then
-    echo "No ramdisk found. Please provide a GKI and/or a vendor ramdisk."
-    exit 1
   fi
 
   if [ -z "${MKBOOTIMG_PATH}" ]; then
@@ -1170,6 +1182,15 @@ if [ ! -z "${BUILD_BOOT_IMG}" ] ; then
       if [ -f "${DIST_DIR}/ramdisk.${RAMDISK_EXT}" ]; then
         MKBOOTIMG_ARGS+=("--vendor_ramdisk" "${DIST_DIR}/ramdisk.${RAMDISK_EXT}")
       fi
+      if [ "${BUILD_INITRAMFS}" = "1" ] \
+          && [ -n "${INITRAMFS_VENDOR_RAMDISK_FRAGMENT_NAME}" ]; then
+        MKBOOTIMG_ARGS+=("--ramdisk_type" "DLKM")
+        for MKBOOTIMG_ARG in ${INITRAMFS_VENDOR_RAMDISK_FRAGMENT_MKBOOTIMG_ARGS}; do
+          MKBOOTIMG_ARGS+=("${MKBOOTIMG_ARG}")
+        done
+        MKBOOTIMG_ARGS+=("--ramdisk_name" "${INITRAMFS_VENDOR_RAMDISK_FRAGMENT_NAME}")
+        MKBOOTIMG_ARGS+=("--vendor_ramdisk_fragment" "${DIST_DIR}/initramfs.img")
+      fi
     fi
   else
     if [ -f "${DIST_DIR}/ramdisk.${RAMDISK_EXT}" ]; then