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author | Linus Torvalds <torvalds@linux-foundation.org> | 2014-08-14 09:53:39 -0600 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-08-14 09:53:39 -0600 |
commit | ae36e95cf81c98b111b84317adeb358aaffa80e2 (patch) | |
tree | 87ef144d3392cca199448117a737c657b7c4663a /Documentation/devicetree | |
parent | cc8a44c671fd3a2c792e9e1f59ea1df52697cc8b (diff) | |
parent | 663d3f7c2e5e1b018a4c53277ccfde40329d98ca (diff) | |
download | op-kernel-dev-ae36e95cf81c98b111b84317adeb358aaffa80e2.zip op-kernel-dev-ae36e95cf81c98b111b84317adeb358aaffa80e2.tar.gz |
Merge tag 'devicetree-for-linus' of git://git.secretlab.ca/git/linux
Pull device tree updates from Grant Likely:
"The branch contains the following device tree changes the v3.17 merge
window:
Group changes to the device tree. In preparation for adding device
tree overlay support, OF_DYNAMIC is reworked so that a set of device
tree changes can be prepared and applied to the tree all at once.
OF_RECONFIG notifiers see the most significant change here so that
users always get a consistent view of the tree. Notifiers generation
is moved from before a change to after it, and notifiers for a group
of changes are emitted after the entire block of changes have been
applied
Automatic console selection from DT. Console drivers can now use
of_console_check() to see if the device node is specified as a console
device. If so then it gets added as a preferred console. UART
devices get this support automatically when uart_add_one_port() is
called.
DT unit tests no longer depend on pre-loaded data in the device tree.
Data is loaded dynamically at the start of unit tests, and then
unloaded again when the tests have completed.
Also contains a few bugfixes for reserved regions and early memory
setup"
* tag 'devicetree-for-linus' of git://git.secretlab.ca/git/linux: (21 commits)
of: Fixing OF Selftest build error
drivers: of: add automated assignment of reserved regions to client devices
of: Use proper types for checking memory overflow
of: typo fix in __of_prop_dup()
Adding selftest testdata dynamically into live tree
of: Add todo tasklist for Devicetree
of: Transactional DT support.
of: Reorder device tree changes and notifiers
of: Move dynamic node fixups out of powerpc and into common code
of: Make sure attached nodes don't carry along extra children
of: Make devicetree sysfs update functions consistent.
of: Create unlocked versions of node and property add/remove functions
OF: Utility helper functions for dynamic nodes
of: Move CONFIG_OF_DYNAMIC code into a separate file
of: rename of_aliases_mutex to just of_mutex
of/platform: Fix of_platform_device_destroy iteration of devices
of: Migrate of_find_node_by_name() users to for_each_node_by_name()
tty: Update hypervisor tty drivers to use core stdout parsing code.
arm/versatile: Add the uart as the stdout device.
of: Enable console on serial ports specified by /chosen/stdout-path
...
Diffstat (limited to 'Documentation/devicetree')
-rw-r--r-- | Documentation/devicetree/changesets.txt | 40 | ||||
-rw-r--r-- | Documentation/devicetree/todo.txt | 11 |
2 files changed, 51 insertions, 0 deletions
diff --git a/Documentation/devicetree/changesets.txt b/Documentation/devicetree/changesets.txt new file mode 100644 index 0000000..935ba5a --- /dev/null +++ b/Documentation/devicetree/changesets.txt @@ -0,0 +1,40 @@ +A DT changeset is a method which allows one to apply changes +in the live tree in such a way that either the full set of changes +will be applied, or none of them will be. If an error occurs partway +through applying the changeset, then the tree will be rolled back to the +previous state. A changeset can also be removed after it has been +applied. + +When a changeset is applied, all of the changes get applied to the tree +at once before emitting OF_RECONFIG notifiers. This is so that the +receiver sees a complete and consistent state of the tree when it +receives the notifier. + +The sequence of a changeset is as follows. + +1. of_changeset_init() - initializes a changeset + +2. A number of DT tree change calls, of_changeset_attach_node(), +of_changeset_detach_node(), of_changeset_add_property(), +of_changeset_remove_property, of_changeset_update_property() to prepare +a set of changes. No changes to the active tree are made at this point. +All the change operations are recorded in the of_changeset 'entries' +list. + +3. mutex_lock(of_mutex) - starts a changeset; The global of_mutex +ensures there can only be one editor at a time. + +4. of_changeset_apply() - Apply the changes to the tree. Either the +entire changeset will get applied, or if there is an error the tree will +be restored to the previous state + +5. mutex_unlock(of_mutex) - All operations complete, release the mutex + +If a successfully applied changeset needs to be removed, it can be done +with the following sequence. + +1. mutex_lock(of_mutex) + +2. of_changeset_revert() + +3. mutex_unlock(of_mutex) diff --git a/Documentation/devicetree/todo.txt b/Documentation/devicetree/todo.txt new file mode 100644 index 0000000..c3cf065 --- /dev/null +++ b/Documentation/devicetree/todo.txt @@ -0,0 +1,11 @@ +Todo list for devicetree: + +=== General structure === +- Switch from custom lists to (h)list_head for nodes and properties structure +- Remove of_allnodes list and iterate using list of child nodes alone + +=== CONFIG_OF_DYNAMIC === +- Switch to RCU for tree updates and get rid of global spinlock +- Document node lifecycle for CONFIG_OF_DYNAMIC +- Always set ->full_name at of_attach_node() time +- pseries: Get rid of open-coded tree modification from arch/powerpc/platforms/pseries/dlpar.c |