Add some README.md text for init triggers.
Bug: 180475195
Test: N/A
Change-Id: I33ec5a03b6aced835f15315b1755e17d07969d4c
diff --git a/init/README.md b/init/README.md
index 75dc328..4b04628 100644
--- a/init/README.md
+++ b/init/README.md
@@ -406,6 +406,33 @@
3. Any time that property c transitions to value d, while property a already equals b.
+Trigger Sequence
+----------------
+
+Init uses the following sequence of triggers during early boot. These are the
+built-in triggers defined in init.cpp.
+
+ 1. `early-init` - The first in the sequence, triggered after cgroups has been configured
+ but before ueventd's coldboot is complete.
+ 2. `init` - Triggered after coldboot is complete.
+ 3. `charger` - Triggered if `ro.bootmode == "charger"`.
+ 4. `late-init` - Triggered if `ro.bootmode != "charger"`, or via healthd triggering a boot
+ from charging mode.
+
+Remaining triggers are configured in `init.rc` and are not built-in. The default sequence for
+these is specified under the "on late-init" event in `init.rc`. Actions internal to `init.rc`
+have been omitted.
+
+ 1. `early-fs` - Start vold.
+ 2. `fs` - Vold is up. Mount partitions not marked as first-stage or latemounted.
+ 3. `post-fs` - Configure anything dependent on early mounts.
+ 4. `late-fs` - Mount partitions marked as latemounted.
+ 5. `post-fs-data` - Mount and configure `/data`; set up encryption. `/metadata` is
+ reformatted here if it couldn't mount in first-stage init.
+ 6. `zygote-start` - Start the zygote.
+ 7. `early-boot` - After zygote has started.
+ 8. `boot` - After `early-boot` actions have completed.
+
Commands
--------