update-prebuilts.sh: add a script help to download the script

to avoid problem caused by typo or any other case

Test: test with the download of 6423191 prebuilts

Signed-off-by: Yongqin Liu <yongqin.liu@linaro.org>
Change-Id: I253dfd591620a57c54db551715b2ee76550bb420
diff --git a/update-prebuilts.sh b/update-prebuilts.sh
new file mode 100755
index 0000000..28b10e5
--- /dev/null
+++ b/update-prebuilts.sh
@@ -0,0 +1,41 @@
+#!/bin/bash -ex
+
+function wget_wrapper(){
+    local build_num="${1}" && shift
+    local board="${1}" && shift
+    local target_name="${1}" && shift
+    local local_name="${1}" && shift
+    wget https://ci.android.com/builds/submitted/${build_num}/kernel_${board}/latest/raw/${target_name} -O ${local_name}
+}
+
+function update_kernel_dtb_hikey960(){
+    local build_num="${1}" && shift
+    local kernel_version="${1}" && shift
+    local board="hikey960"
+    wget_wrapper ${build_num} ${board} Image.gz-dtb Image.gz-dtb-hikey960-${kernel_version}
+    wget_wrapper ${build_num} ${board} hi3660-hikey960.dtb hi3660-hikey960.dtb-${kernel_version}
+    wget_wrapper ${build_num} ${board} manifest_${build_num}.xml manifest_${build_num}-${board}.xml
+}
+
+
+function update_kernel_dtb_hikey(){
+    local build_num="${1}" && shift
+    local kernel_version="${1}" && shift
+    local board="hikey"
+    wget_wrapper ${build_num} ${board} Image.gz-dtb Image.gz-dtb-${kernel_version}
+    wget_wrapper ${build_num} ${board} hi6220-hikey.dtb hi6220-hikey.dtb-${kernel_version}
+    wget_wrapper ${build_num} ${board} manifest_${build_num}.xml manifest_${build_num}-${board}.xml
+}
+
+function update_kernel_dtb(){
+    local build_num="${1}" && shift
+    local kernel_version="${1}" && shift
+
+    update_kernel_dtb_hikey960 ${build_num} ${kernel_version}
+    update_kernel_dtb_hikey ${build_num} ${kernel_version}
+}
+
+# https://ci.android.com/builds/branches/aosp_kernel-hikey-linaro-android-4.19/grid?
+# https://ci.android.com/builds/submitted/6423191/kernel_hikey960/latest
+# https://ci.android.com/builds/submitted/6423191/kernel_hikey/latest
+update_kernel_dtb 6423191 4.19