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-rw-r--r--Documentation/devicetree/of_selftest.txt211
-rw-r--r--drivers/of/base.c16
-rw-r--r--drivers/of/dynamic.c3
-rw-r--r--drivers/of/fdt.c14
4 files changed, 237 insertions, 7 deletions
diff --git a/Documentation/devicetree/of_selftest.txt b/Documentation/devicetree/of_selftest.txt
new file mode 100644
index 0000000..3a2f54d
--- /dev/null
+++ b/Documentation/devicetree/of_selftest.txt
@@ -0,0 +1,211 @@
+Open Firmware Device Tree Selftest
+----------------------------------
+
+Author: Gaurav Minocha <gaurav.minocha.os@gmail.com>
+
+1. Introduction
+
+This document explains how the test data required for executing OF selftest
+is attached to the live tree dynamically, independent of the machine's
+architecture.
+
+It is recommended to read the following documents before moving ahead.
+
+[1] Documentation/devicetree/usage-model.txt
+[2] http://www.devicetree.org/Device_Tree_Usage
+
+OF Selftest has been designed to test the interface (include/linux/of.h)
+provided to device driver developers to fetch the device information..etc.
+from the unflattened device tree data structure. This interface is used by
+most of the device drivers in various use cases.
+
+
+2. Test-data
+
+The Device Tree Source file (drivers/of/testcase-data/testcases.dts) contains
+the test data required for executing the unit tests automated in
+drivers/of/selftests.c. Currently, following Device Tree Source Include files
+(.dtsi) are included in testcase.dts:
+
+drivers/of/testcase-data/tests-interrupts.dtsi
+drivers/of/testcase-data/tests-platform.dtsi
+drivers/of/testcase-data/tests-phandle.dtsi
+drivers/of/testcase-data/tests-match.dtsi
+
+When the kernel is build with OF_SELFTEST enabled, then the following make rule
+
+$(obj)/%.dtb: $(src)/%.dts FORCE
+ $(call if_changed_dep, dtc)
+
+is used to compile the DT source file (testcase.dts) into a binary blob
+(testcase.dtb), also referred as flattened DT.
+
+After that, using the following rule the binary blob above is wrapped as an
+assembly file (testcase.dtb.S).
+
+$(obj)/%.dtb.S: $(obj)/%.dtb
+ $(call cmd, dt_S_dtb)
+
+The assembly file is compiled into an object file (testcase.dtb.o), and is
+linked into the kernel image.
+
+
+2.1. Adding the test data
+
+Un-flattened device tree structure:
+
+Un-flattened device tree consists of connected device_node(s) in form of a tree
+structure described below.
+
+// following struct members are used to construct the tree
+struct device_node {
+ ...
+ struct device_node *parent;
+ struct device_node *child;
+ struct device_node *sibling;
+ struct device_node *allnext; /* next in list of all nodes */
+ ...
+ };
+
+Figure 1, describes a generic structure of machine’s un-flattened device tree
+considering only child and sibling pointers. There exists another pointer,
+*parent, that is used to traverse the tree in the reverse direction. So, at
+a particular level the child node and all the sibling nodes will have a parent
+pointer pointing to a common node (e.g. child1, sibling2, sibling3, sibling4’s
+parent points to root node)
+
+root (‘/’)
+ |
+child1 -> sibling2 -> sibling3 -> sibling4 -> null
+ | | | |
+ | | | null
+ | | |
+ | | child31 -> sibling32 -> null
+ | | | |
+ | | null null
+ | |
+ | child21 -> sibling22 -> sibling23 -> null
+ | | | |
+ | null null null
+ |
+child11 -> sibling12 -> sibling13 -> sibling14 -> null
+ | | | |
+ | | | null
+ | | |
+ null null child131 -> null
+ |
+ null
+
+Figure 1: Generic structure of un-flattened device tree
+
+
+*allnext: it is used to link all the nodes of DT into a list. So, for the
+ above tree the list would be as follows:
+
+root->child1->child11->sibling12->sibling13->child131->sibling14->sibling2->
+child21->sibling22->sibling23->sibling3->child31->sibling32->sibling4->null
+
+Before executing OF selftest, it is required to attach the test data to
+machine's device tree (if present). So, when selftest_data_add() is called,
+at first it reads the flattened device tree data linked into the kernel image
+via the following kernel symbols:
+
+__dtb_testcases_begin - address marking the start of test data blob
+__dtb_testcases_end - address marking the end of test data blob
+
+Secondly, it calls of_fdt_unflatten_device_tree() to unflatten the flattened
+blob. And finally, if the machine’s device tree (i.e live tree) is present,
+then it attaches the unflattened test data tree to the live tree, else it
+attaches itself as a live device tree.
+
+attach_node_and_children() uses of_attach_node() to attach the nodes into the
+live tree as explained below. To explain the same, the test data tree described
+ in Figure 2 is attached to the live tree described in Figure 1.
+
+root (‘/’)
+ |
+ testcase-data
+ |
+ test-child0 -> test-sibling1 -> test-sibling2 -> test-sibling3 -> null
+ | | | |
+ test-child01 null null null
+
+
+allnext list:
+
+root->testcase-data->test-child0->test-child01->test-sibling1->test-sibling2
+->test-sibling3->null
+
+Figure 2: Example test data tree to be attached to live tree.
+
+According to the scenario above, the live tree is already present so it isn’t
+required to attach the root(‘/’) node. All other nodes are attached by calling
+of_attach_node() on each node.
+
+In the function of_attach_node(), the new node is attached as the child of the
+given parent in live tree. But, if parent already has a child then the new node
+replaces the current child and turns it into its sibling. So, when the testcase
+data node is attached to the live tree above (Figure 1), the final structure is
+ as shown in Figure 3.
+
+root (‘/’)
+ |
+testcase-data -> child1 -> sibling2 -> sibling3 -> sibling4 -> null
+ | | | | |
+ (...) | | | null
+ | | child31 -> sibling32 -> null
+ | | | |
+ | | null null
+ | |
+ | child21 -> sibling22 -> sibling23 -> null
+ | | | |
+ | null null null
+ |
+ child11 -> sibling12 -> sibling13 -> sibling14 -> null
+ | | | |
+ null null | null
+ |
+ child131 -> null
+ |
+ null
+-----------------------------------------------------------------------
+
+root (‘/’)
+ |
+testcase-data -> child1 -> sibling2 -> sibling3 -> sibling4 -> null
+ | | | | |
+ | (...) (...) (...) null
+ |
+test-sibling3 -> test-sibling2 -> test-sibling1 -> test-child0 -> null
+ | | | |
+ null null null test-child01
+
+
+Figure 3: Live device tree structure after attaching the testcase-data.
+
+
+Astute readers would have noticed that test-child0 node becomes the last
+sibling compared to the earlier structure (Figure 2). After attaching first
+test-child0 the test-sibling1 is attached that pushes the child node
+(i.e. test-child0) to become a sibling and makes itself a child node,
+ as mentioned above.
+
+If a duplicate node is found (i.e. if a node with same full_name property is
+already present in the live tree), then the node isn’t attached rather its
+properties are updated to the live tree’s node by calling the function
+update_node_properties().
+
+
+2.2. Removing the test data
+
+Once the test case execution is complete, selftest_data_remove is called in
+order to remove the device nodes attached initially (first the leaf nodes are
+detached and then moving up the parent nodes are removed, and eventually the
+whole tree). selftest_data_remove() calls detach_node_and_children() that uses
+of_detach_node() to detach the nodes from the live device tree.
+
+To detach a node, of_detach_node() first updates all_next linked list, by
+attaching the previous node’s allnext to current node’s allnext pointer. And
+then, it either updates the child pointer of given node’s parent to its
+sibling or attaches the previous sibling to the given node’s sibling, as
+appropriate. That is it :)
diff --git a/drivers/of/base.c b/drivers/of/base.c
index d8574ad..293ed4b 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -138,6 +138,9 @@ int __of_add_property_sysfs(struct device_node *np, struct property *pp)
/* Important: Don't leak passwords */
bool secure = strncmp(pp->name, "security-", 9) == 0;
+ if (!IS_ENABLED(CONFIG_SYSFS))
+ return 0;
+
if (!of_kset || !of_node_is_attached(np))
return 0;
@@ -158,6 +161,9 @@ int __of_attach_node_sysfs(struct device_node *np)
struct property *pp;
int rc;
+ if (!IS_ENABLED(CONFIG_SYSFS))
+ return 0;
+
if (!of_kset)
return 0;
@@ -1713,6 +1719,9 @@ int __of_remove_property(struct device_node *np, struct property *prop)
void __of_remove_property_sysfs(struct device_node *np, struct property *prop)
{
+ if (!IS_ENABLED(CONFIG_SYSFS))
+ return;
+
/* at early boot, bail here and defer setup to of_init() */
if (of_kset && of_node_is_attached(np))
sysfs_remove_bin_file(&np->kobj, &prop->attr);
@@ -1777,6 +1786,9 @@ int __of_update_property(struct device_node *np, struct property *newprop,
void __of_update_property_sysfs(struct device_node *np, struct property *newprop,
struct property *oldprop)
{
+ if (!IS_ENABLED(CONFIG_SYSFS))
+ return;
+
/* At early boot, bail out and defer setup to of_init() */
if (!of_kset)
return;
@@ -1847,6 +1859,7 @@ void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align))
{
struct property *pp;
+ of_aliases = of_find_node_by_path("/aliases");
of_chosen = of_find_node_by_path("/chosen");
if (of_chosen == NULL)
of_chosen = of_find_node_by_path("/chosen@0");
@@ -1862,7 +1875,6 @@ void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align))
of_stdout = of_find_node_by_path(name);
}
- of_aliases = of_find_node_by_path("/aliases");
if (!of_aliases)
return;
@@ -1986,7 +1998,7 @@ bool of_console_check(struct device_node *dn, char *name, int index)
{
if (!dn || dn != of_stdout || console_set_on_cmdline)
return false;
- return add_preferred_console(name, index, NULL);
+ return !add_preferred_console(name, index, NULL);
}
EXPORT_SYMBOL_GPL(of_console_check);
diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c
index 54fecc4..f297891 100644
--- a/drivers/of/dynamic.c
+++ b/drivers/of/dynamic.c
@@ -45,6 +45,9 @@ void __of_detach_node_sysfs(struct device_node *np)
{
struct property *pp;
+ if (!IS_ENABLED(CONFIG_SYSFS))
+ return;
+
BUG_ON(!of_node_is_initialized(np));
if (!of_kset)
return;
diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 79cb831..d1ffca8 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -928,7 +928,11 @@ int __init early_init_dt_scan_chosen(unsigned long node, const char *uname,
void __init __weak early_init_dt_add_memory_arch(u64 base, u64 size)
{
const u64 phys_offset = __pa(PAGE_OFFSET);
- base &= PAGE_MASK;
+
+ if (!PAGE_ALIGNED(base)) {
+ size -= PAGE_SIZE - (base & ~PAGE_MASK);
+ base = PAGE_ALIGN(base);
+ }
size &= PAGE_MASK;
if (base > MAX_PHYS_ADDR) {
@@ -937,10 +941,10 @@ void __init __weak early_init_dt_add_memory_arch(u64 base, u64 size)
return;
}
- if (base + size > MAX_PHYS_ADDR) {
- pr_warning("Ignoring memory range 0x%lx - 0x%llx\n",
- ULONG_MAX, base + size);
- size = MAX_PHYS_ADDR - base;
+ if (base + size - 1 > MAX_PHYS_ADDR) {
+ pr_warning("Ignoring memory range 0x%llx - 0x%llx\n",
+ ((u64)MAX_PHYS_ADDR) + 1, base + size);
+ size = MAX_PHYS_ADDR - base + 1;
}
if (base + size < phys_offset) {
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