Lines Matching refs:the

8 This document explains how the test data required for executing OF unittest
9 is attached to the live tree dynamically, independent of the machine's
12 It is recommended to read the following documents before moving ahead.
17 OF Selftest has been designed to test the interface (include/linux/of.h)
18 provided to device driver developers to fetch the device information..etc.
19 from the unflattened device tree data structure. This interface is used by
20 most of the device drivers in various use cases.
26 the test data required for executing the unit tests automated in
35 When the kernel is build with OF_SELFTEST enabled, then the following make rule
40 is used to compile the DT source file (testcases.dts) into a binary blob
43 After that, using the following rule the binary blob above is wrapped as an
50 linked into the kernel image.
53 2.1. Adding the test data
60 // following struct members are used to construct the tree
71 *parent, that is used to traverse the tree in the reverse direction. So, at
72 a particular level the child node and all the sibling nodes will have a parent
101 Before executing OF unittest, it is required to attach the test data to
103 at first it reads the flattened device tree data linked into the kernel image
104 via the following kernel symbols:
106 __dtb_testcases_begin - address marking the start of test data blob
107 __dtb_testcases_end   - address marking the end of test data blob
109 Secondly, it calls of_fdt_unflatten_tree() to unflatten the flattened
110 blob. And finally, if the machine's device tree (i.e live tree) is present,
111 then it attaches the unflattened test data tree to the live tree, else it
114 attach_node_and_children() uses of_attach_node() to attach the nodes into the
115 live tree as explained below. To explain the same, the test data tree described
116  in Figure 2 is attached to the live tree described in Figure 1.
129 According to the scenario above, the live tree is already present so it isn't
130 required to attach the root('/') node. All other nodes are attached by calling
133 In the function of_attach_node(), the new node is attached as the child of the
134 given parent in live tree. But, if parent already has a child then the new node
135 replaces the current child and turns it into its sibling. So, when the testcase
136 data node is attached to the live tree above (Figure 1), the final structure is
172 Figure 3: Live device tree structure after attaching the testcase-data.
175 Astute readers would have noticed that test-child0 node becomes the last
176 sibling compared to the earlier structure (Figure 2). After attaching first
177 test-child0 the test-sibling1 is attached that pushes the child node
182 already present in the live tree), then the node isn't attached rather its
183 properties are updated to the live tree's node by calling the function
187 2.2. Removing the test data
189 Once the test case execution is complete, selftest_data_remove is called in
190 order to remove the device nodes attached initially (first the leaf nodes are
191 detached and then moving up the parent nodes are removed, and eventually the
193 of_detach_node() to detach the nodes from the live device tree.
195 To detach a node, of_detach_node() either updates the child pointer of given
196 node's parent to its sibling or attaches the previous sibling to the given