96 lines
2.8 KiB
ReStructuredText
96 lines
2.8 KiB
ReStructuredText
===========
|
|
Notifier Chain
|
|
===========
|
|
|
|
NuttX provides a callback list mechanism called *Notifier Chain*.
|
|
Notifier chain is essentially a list of callbacks used at certain times,
|
|
such as system asserting, powering off and restarting.
|
|
|
|
**Notifier chain** is very much like the Linux notifier chains, except
|
|
for some implementation differences.
|
|
|
|
Classes of Notifier Chain
|
|
======================
|
|
|
|
There are currently two different classes of notifier.
|
|
|
|
Atomic notifier chains
|
|
-------------------------------
|
|
|
|
Atomic notifier chains: Chain callbacks run in interrupt/atomic context.
|
|
In Nuttx, callouts are allowed to block(In Linux, callouts in atomic
|
|
notifier chain are not allowed to block). One example of an Atomic notifier
|
|
chain is turning off FPU when asserting.
|
|
|
|
Blocking notifier chains:
|
|
------------------------------
|
|
|
|
Blocking notifier chains: Chain callbacks run in process context.
|
|
Callouts are allowed to block. One example of a blocking notifier chain
|
|
is when an orderly powering off is needed.
|
|
|
|
Common Notifier Chain Interfaces
|
|
============================
|
|
|
|
Notifier Block Types
|
|
--------------------------
|
|
|
|
- ``struct notifier_block``. Defines one notifier callback entry.
|
|
|
|
Notifier Chain Interfaces
|
|
---------------------
|
|
|
|
.. c:function:: void panic_notifier_chain_register(FAR struct notifier_block *nb)
|
|
|
|
Add notifier to the panic notifier chain.
|
|
|
|
The panic notifier chain is an atomic notifier chain. It will be called
|
|
when asserting.
|
|
|
|
:param nb: New entry in notifier chain.
|
|
|
|
.. c:function:: void panic_notifier_chain_unregister(FAR struct notifier_block *nb)
|
|
|
|
Remove notifier from the panic notifier chain.
|
|
|
|
The panic notifier chain is an atomic notifier chain. It will be called
|
|
when asserting.
|
|
|
|
:param nh: Entry to remove from notifier chain.
|
|
|
|
.. c:function:: void panic_notifier_call_chain(unsigned long action, FAR void *data)
|
|
|
|
Call functions in the panic notifier chain.
|
|
|
|
The panic notifier chain is an atomic notifier chain. It will be called
|
|
when asserting.
|
|
|
|
:param action: Value passed unmodified to notifier function.
|
|
:param data: Pointer passed unmodified to notifier function.
|
|
|
|
.. c:function:: void register_reboot_notifier(FAR struct notifier_block *nb)
|
|
|
|
Add notifier to the reboot notifier chain.
|
|
|
|
The reboot notifier chain is an atomic notifier chain.
|
|
|
|
:param nb: New entry in notifier chain.
|
|
|
|
.. c:function:: void unregister_reboot_notifier(FAR struct notifier_block *nb)
|
|
|
|
Remove notifier from the reboot notifier chain.
|
|
|
|
The reboot notifier chain is an atomic notifier chain.
|
|
|
|
:param nh: Entry to remove from notifier chain.
|
|
|
|
.. c:function:: void reboot_notifier_call_chain(unsigned long action, FAR void *data)
|
|
|
|
Call functions in the reboot notifier chain.
|
|
|
|
The reboot notifier chain is an atomic notifier chain.
|
|
|
|
:param action: Value passed unmodified to notifier function.
|
|
:param data: Pointer passed unmodified to notifier function.
|
|
|