Merge branch 'linux-linaro-lsk' into linux-linaro-lsk-android

4 files changed, 226 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-firmware-ofw b/Documentation/ABI/testing/sysfs-firmware-ofw
new file mode 100644
index 000000000000..f562b188e71d
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-firmware-ofw
@@ -0,0 +1,28 @@
+What:		/sys/firmware/devicetree/*
+Date:		November 2013
+Contact:	Grant Likely <grant.likely@linaro.org>
+Description:
+		When using OpenFirmware or a Flattened Device Tree to enumerate
+		hardware, the device tree structure will be exposed in this
+		directory.
+
+		It is possible for multiple device-tree directories to exist.
+		Some device drivers use a separate detached device tree which
+		have no attachment to the system tree and will appear in a
+		different subdirectory under /sys/firmware/devicetree.
+
+		Userspace must not use the /sys/firmware/devicetree/base
+		path directly, but instead should follow /proc/device-tree
+		symlink. It is possible that the absolute path will change
+		in the future, but the symlink is the stable ABI.
+
+		The /proc/device-tree symlink replaces the devicetree /proc
+		filesystem support, and has largely the same semantics and
+		should be compatible with existing userspace.
+
+		The contents of /sys/firmware/devicetree/ is a
+		hierarchy of directories, one per device tree node. The
+		directory name is the resolved path component name (node
+		name plus address). Properties are represented as files
+		in the directory. The contents of each file is the exact
+		binary data from the device tree.
diff --git a/Documentation/devicetree/changesets.txt b/Documentation/devicetree/changesets.txt
new file mode 100644
index 000000000000..935ba5acc34e
--- /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/dynamic-resolution-notes.txt b/Documentation/devicetree/dynamic-resolution-notes.txt
new file mode 100644
index 000000000000..083d23262abe
--- /dev/null
+++ b/Documentation/devicetree/dynamic-resolution-notes.txt
@@ -0,0 +1,25 @@
+Device Tree Dynamic Resolver Notes
+----------------------------------
+
+This document describes the implementation of the in-kernel
+Device Tree resolver, residing in drivers/of/resolver.c and is a
+companion document to Documentation/devicetree/dt-object-internal.txt[1]
+
+How the resolver works
+----------------------
+
+The resolver is given as an input an arbitrary tree compiled with the
+proper dtc option and having a /plugin/ tag. This generates the
+appropriate __fixups__ & __local_fixups__ nodes as described in [1].
+
+In sequence the resolver works by the following steps:
+
+1. Get the maximum device tree phandle value from the live tree + 1.
+2. Adjust all the local phandles of the tree to resolve by that amount.
+3. Using the __local__fixups__ node information adjust all local references
+   by the same amount.
+4. For each property in the __fixups__ node locate the node it references
+   in the live tree. This is the label used to tag the node.
+5. Retrieve the phandle of the target of the fixup.
+6. For each fixup in the property locate the node:property:offset location
+   and replace it with the phandle value.
diff --git a/Documentation/devicetree/overlay-notes.txt b/Documentation/devicetree/overlay-notes.txt
new file mode 100644
index 000000000000..30ae758e3eef
--- /dev/null
+++ b/Documentation/devicetree/overlay-notes.txt
@@ -0,0 +1,133 @@
+Device Tree Overlay Notes
+-------------------------
+
+This document describes the implementation of the in-kernel
+device tree overlay functionality residing in drivers/of/overlay.c and is a
+companion document to Documentation/devicetree/dt-object-internal.txt[1] &
+Documentation/devicetree/dynamic-resolution-notes.txt[2]
+
+How overlays work
+-----------------
+
+A Device Tree's overlay purpose is to modify the kernel's live tree, and
+have the modification affecting the state of the the kernel in a way that
+is reflecting the changes.
+Since the kernel mainly deals with devices, any new device node that result
+in an active device should have it created while if the device node is either
+disabled or removed all together, the affected device should be deregistered.
+
+Lets take an example where we have a foo board with the following base tree
+which is taken from [1].
+
+---- foo.dts -----------------------------------------------------------------
+	/* FOO platform */
+	/ {
+		compatible = "corp,foo";
+
+		/* shared resources */
+		res: res {
+		};
+
+		/* On chip peripherals */
+		ocp: ocp {
+			/* peripherals that are always instantiated */
+			peripheral1 { ... };
+		}
+	};
+---- foo.dts -----------------------------------------------------------------
+
+The overlay bar.dts, when loaded (and resolved as described in [2]) should
+
+---- bar.dts -----------------------------------------------------------------
+/plugin/;	/* allow undefined label references and record them */
+/ {
+	....	/* various properties for loader use; i.e. part id etc. */
+	fragment@0 {
+		target = <&ocp>;
+		__overlay__ {
+			/* bar peripheral */
+			bar {
+				compatible = "corp,bar";
+				... /* various properties and child nodes */
+			}
+		};
+	};
+};
+---- bar.dts -----------------------------------------------------------------
+
+result in foo+bar.dts
+
+---- foo+bar.dts -------------------------------------------------------------
+	/* FOO platform + bar peripheral */
+	/ {
+		compatible = "corp,foo";
+
+		/* shared resources */
+		res: res {
+		};
+
+		/* On chip peripherals */
+		ocp: ocp {
+			/* peripherals that are always instantiated */
+			peripheral1 { ... };
+
+			/* bar peripheral */
+			bar {
+				compatible = "corp,bar";
+				... /* various properties and child nodes */
+			}
+		}
+	};
+---- foo+bar.dts -------------------------------------------------------------
+
+As a result of the the overlay, a new device node (bar) has been created
+so a bar platform device will be registered and if a matching device driver
+is loaded the device will be created as expected.
+
+Overlay in-kernel API
+--------------------------------
+
+The API is quite easy to use.
+
+1. Call of_overlay_create() to create and apply an overlay. The return value
+is a cookie identifying this overlay.
+
+2. Call of_overlay_destroy() to remove and cleanup the overlay previously
+created via the call to of_overlay_create(). Removal of an overlay that
+is stacked by another will not be permitted.
+
+Finally, if you need to remove all overlays in one-go, just call
+of_overlay_destroy_all() which will remove every single one in the correct
+order.
+
+Overlay DTS Format
+------------------
+
+The DTS of an overlay should have the following format:
+
+{
+	/* ignored properties by the overlay */
+
+	fragment@0 {	/* first child node */
+
+		target=<phandle>;	/* phandle target of the overlay */
+	or
+		target-path="/path";	/* target path of the overlay */
+
+		__overlay__ {
+			property-a;	/* add property-a to the target */
+			node-a {	/* add to an existing, or create a node-a */
+				...
+			};
+		};
+	}
+	fragment@1 {	/* second child node */
+		...
+	};
+	/* more fragments follow */
+}
+
+Using the non-phandle based target method allows one to use a base DT which does
+not contain a __symbols__ node, i.e. it was not compiled with the -@ option.
+The __symbols__ node is only required for the target=<phandle> method, since it
+contains the information required to map from a phandle to a tree location.