* [PATCH 1/2] OF: Introduce Device Tree resolve support.
[not found] ` <1412263624-21838-1-git-send-email-grant.likely-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
@ 2014-10-02 15:27 ` Grant Likely
2014-10-02 15:27 ` [PATCH 2/2] of/selftest: Use the resolver to fixup phandles Grant Likely
1 sibling, 0 replies; 3+ messages in thread
From: Grant Likely @ 2014-10-02 15:27 UTC (permalink / raw)
To: devicetree-u79uwXL29TY76Z2rM5mHXA; +Cc: Pantelis Antoniou, Grant Likely
From: Pantelis Antoniou <pantelis.antoniou-OWPKS81ov/FWk0Htik3J/w@public.gmane.org>
Introduce support for dynamic device tree resolution.
Using it, it is possible to prepare a device tree that's
been loaded on runtime to be modified and inserted at the kernel
live tree.
Export of of_resolve and bug fix of double free by
Guenter Roeck <groeck-3r7Miqu9kMnR7s880joybQ@public.gmane.org>
Signed-off-by: Pantelis Antoniou <pantelis.antoniou-OWPKS81ov/FWk0Htik3J/w@public.gmane.org>
[grant.likely: Don't need to select CONFIG_OF_DYNAMIC and CONFIG_OF_DEVICE]
[grant.likely: Don't need to depend on OF or !SPARC]
[grant.likely: Factor out duplicate code blocks into single function]
Signed-off-by: Grant Likely <grant.likely-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
---
.../devicetree/dynamic-resolution-notes.txt | 25 ++
drivers/of/Kconfig | 3 +
drivers/of/Makefile | 1 +
drivers/of/resolver.c | 336 +++++++++++++++++++++
include/linux/of.h | 3 +
5 files changed, 368 insertions(+)
create mode 100644 Documentation/devicetree/dynamic-resolution-notes.txt
create mode 100644 drivers/of/resolver.c
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/drivers/of/Kconfig b/drivers/of/Kconfig
index 5160c4eb73c2..6b81a36f6420 100644
--- a/drivers/of/Kconfig
+++ b/drivers/of/Kconfig
@@ -79,4 +79,7 @@ config OF_RESERVED_MEM
help
Helpers to allow for reservation of memory regions
+config OF_RESOLVE
+ bool
+
endmenu # OF
diff --git a/drivers/of/Makefile b/drivers/of/Makefile
index 2b6a7b129d10..ca9209ce50cd 100644
--- a/drivers/of/Makefile
+++ b/drivers/of/Makefile
@@ -13,6 +13,7 @@ obj-$(CONFIG_OF_PCI) += of_pci.o
obj-$(CONFIG_OF_PCI_IRQ) += of_pci_irq.o
obj-$(CONFIG_OF_MTD) += of_mtd.o
obj-$(CONFIG_OF_RESERVED_MEM) += of_reserved_mem.o
+obj-$(CONFIG_OF_RESOLVE) += resolver.o
CFLAGS_fdt.o = -I$(src)/../../scripts/dtc/libfdt
CFLAGS_fdt_address.o = -I$(src)/../../scripts/dtc/libfdt
diff --git a/drivers/of/resolver.c b/drivers/of/resolver.c
new file mode 100644
index 000000000000..aed7959f800d
--- /dev/null
+++ b/drivers/of/resolver.c
@@ -0,0 +1,336 @@
+/*
+ * Functions for dealing with DT resolution
+ *
+ * Copyright (C) 2012 Pantelis Antoniou <panto-wVdstyuyKrO8r51toPun2/C9HSW9iNxf@public.gmane.org>
+ * Copyright (C) 2012 Texas Instruments Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/string.h>
+#include <linux/ctype.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+
+/* illegal phandle value (set when unresolved) */
+#define OF_PHANDLE_ILLEGAL 0xdeadbeef
+
+/**
+ * Find a node with the give full name by recursively following any of
+ * the child node links.
+ */
+static struct device_node *__of_find_node_by_full_name(struct device_node *node,
+ const char *full_name)
+{
+ struct device_node *child, *found;
+
+ if (node == NULL)
+ return NULL;
+
+ /* check */
+ if (of_node_cmp(node->full_name, full_name) == 0)
+ return node;
+
+ for_each_child_of_node(node, child) {
+ found = __of_find_node_by_full_name(child, full_name);
+ if (found != NULL)
+ return found;
+ }
+
+ return NULL;
+}
+
+/*
+ * Find live tree's maximum phandle value.
+ */
+static phandle of_get_tree_max_phandle(void)
+{
+ struct device_node *node;
+ phandle phandle;
+ unsigned long flags;
+
+ /* now search recursively */
+ raw_spin_lock_irqsave(&devtree_lock, flags);
+ phandle = 0;
+ for_each_of_allnodes(node) {
+ if (node->phandle != OF_PHANDLE_ILLEGAL &&
+ node->phandle > phandle)
+ phandle = node->phandle;
+ }
+ raw_spin_unlock_irqrestore(&devtree_lock, flags);
+
+ return phandle;
+}
+
+/*
+ * Adjust a subtree's phandle values by a given delta.
+ * Makes sure not to just adjust the device node's phandle value,
+ * but modify the phandle properties values as well.
+ */
+static void __of_adjust_tree_phandles(struct device_node *node,
+ int phandle_delta)
+{
+ struct device_node *child;
+ struct property *prop;
+ phandle phandle;
+
+ /* first adjust the node's phandle direct value */
+ if (node->phandle != 0 && node->phandle != OF_PHANDLE_ILLEGAL)
+ node->phandle += phandle_delta;
+
+ /* now adjust phandle & linux,phandle values */
+ for_each_property_of_node(node, prop) {
+
+ /* only look for these two */
+ if (of_prop_cmp(prop->name, "phandle") != 0 &&
+ of_prop_cmp(prop->name, "linux,phandle") != 0)
+ continue;
+
+ /* must be big enough */
+ if (prop->length < 4)
+ continue;
+
+ /* read phandle value */
+ phandle = be32_to_cpup(prop->value);
+ if (phandle == OF_PHANDLE_ILLEGAL) /* unresolved */
+ continue;
+
+ /* adjust */
+ *(uint32_t *)prop->value = cpu_to_be32(node->phandle);
+ }
+
+ /* now do the children recursively */
+ for_each_child_of_node(node, child)
+ __of_adjust_tree_phandles(child, phandle_delta);
+}
+
+static int __of_adjust_phandle_ref(struct device_node *node, struct property *rprop, int value, bool is_delta)
+{
+ phandle phandle;
+ struct device_node *refnode;
+ struct property *sprop;
+ char *propval, *propcur, *propend, *nodestr, *propstr, *s;
+ int offset, propcurlen;
+ int err = 0;
+
+ /* make a copy */
+ propval = kmalloc(rprop->length, GFP_KERNEL);
+ if (!propval) {
+ pr_err("%s: Could not copy value of '%s'\n",
+ __func__, rprop->name);
+ return -ENOMEM;
+ }
+ memcpy(propval, rprop->value, rprop->length);
+
+ propend = propval + rprop->length;
+ for (propcur = propval; propcur < propend; propcur += propcurlen + 1) {
+ propcurlen = strlen(propcur);
+
+ nodestr = propcur;
+ s = strchr(propcur, ':');
+ if (!s) {
+ pr_err("%s: Illegal symbol entry '%s' (1)\n",
+ __func__, propcur);
+ err = -EINVAL;
+ goto err_fail;
+ }
+ *s++ = '\0';
+
+ propstr = s;
+ s = strchr(s, ':');
+ if (!s) {
+ pr_err("%s: Illegal symbol entry '%s' (2)\n",
+ __func__, (char *)rprop->value);
+ err = -EINVAL;
+ goto err_fail;
+ }
+
+ *s++ = '\0';
+ err = kstrtoint(s, 10, &offset);
+ if (err != 0) {
+ pr_err("%s: Could get offset '%s'\n",
+ __func__, (char *)rprop->value);
+ goto err_fail;
+ }
+
+ /* look into the resolve node for the full path */
+ refnode = __of_find_node_by_full_name(node, nodestr);
+ if (!refnode) {
+ pr_warn("%s: Could not find refnode '%s'\n",
+ __func__, (char *)rprop->value);
+ continue;
+ }
+
+ /* now find the property */
+ for_each_property_of_node(refnode, sprop) {
+ if (of_prop_cmp(sprop->name, propstr) == 0)
+ break;
+ }
+
+ if (!sprop) {
+ pr_err("%s: Could not find property '%s'\n",
+ __func__, (char *)rprop->value);
+ err = -ENOENT;
+ goto err_fail;
+ }
+
+ phandle = is_delta ? be32_to_cpup(sprop->value + offset) + value : value;
+ *(__be32 *)(sprop->value + offset) = cpu_to_be32(phandle);
+ }
+
+err_fail:
+ kfree(propval);
+ return err;
+}
+
+/*
+ * Adjust the local phandle references by the given phandle delta.
+ * Assumes the existances of a __local_fixups__ node at the root
+ * of the tree. Does not take any devtree locks so make sure you
+ * call this on a tree which is at the detached state.
+ */
+static int __of_adjust_tree_phandle_references(struct device_node *node,
+ int phandle_delta)
+{
+ struct device_node *child;
+ struct property *rprop;
+ int err;
+
+ /* locate the symbols & fixups nodes on resolve */
+ for_each_child_of_node(node, child)
+ if (of_node_cmp(child->name, "__local_fixups__") == 0)
+ break;
+
+ /* no local fixups */
+ if (!child)
+ return 0;
+
+ /* find the local fixups property */
+ for_each_property_of_node(child, rprop) {
+ /* skip properties added automatically */
+ if (of_prop_cmp(rprop->name, "name") == 0)
+ continue;
+
+ err = __of_adjust_phandle_ref(node, rprop, phandle_delta, true);
+ if (err)
+ return err;
+ }
+
+ return 0;
+}
+
+/**
+ * of_resolve - Resolve the given node against the live tree.
+ *
+ * @resolve: Node to resolve
+ *
+ * Perform dynamic Device Tree resolution against the live tree
+ * to the given node to resolve. This depends on the live tree
+ * having a __symbols__ node, and the resolve node the __fixups__ &
+ * __local_fixups__ nodes (if needed).
+ * The result of the operation is a resolve node that it's contents
+ * are fit to be inserted or operate upon the live tree.
+ * Returns 0 on success or a negative error value on error.
+ */
+int of_resolve_phandles(struct device_node *resolve)
+{
+ struct device_node *child, *refnode;
+ struct device_node *root_sym, *resolve_sym, *resolve_fix;
+ struct property *rprop;
+ const char *refpath;
+ phandle phandle, phandle_delta;
+ int err;
+
+ /* the resolve node must exist, and be detached */
+ if (!resolve || !of_node_check_flag(resolve, OF_DETACHED))
+ return -EINVAL;
+
+ /* first we need to adjust the phandles */
+ phandle_delta = of_get_tree_max_phandle() + 1;
+ __of_adjust_tree_phandles(resolve, phandle_delta);
+ err = __of_adjust_tree_phandle_references(resolve, phandle_delta);
+ if (err != 0)
+ return err;
+
+ root_sym = NULL;
+ resolve_sym = NULL;
+ resolve_fix = NULL;
+
+ /* this may fail (if no fixups are required) */
+ root_sym = of_find_node_by_path("/__symbols__");
+
+ /* locate the symbols & fixups nodes on resolve */
+ for_each_child_of_node(resolve, child) {
+
+ if (!resolve_sym &&
+ of_node_cmp(child->name, "__symbols__") == 0)
+ resolve_sym = child;
+
+ if (!resolve_fix &&
+ of_node_cmp(child->name, "__fixups__") == 0)
+ resolve_fix = child;
+
+ /* both found, don't bother anymore */
+ if (resolve_sym && resolve_fix)
+ break;
+ }
+
+ /* we do allow for the case where no fixups are needed */
+ if (!resolve_fix) {
+ err = 0; /* no error */
+ goto out;
+ }
+
+ /* we need to fixup, but no root symbols... */
+ if (!root_sym) {
+ err = -EINVAL;
+ goto out;
+ }
+
+ for_each_property_of_node(resolve_fix, rprop) {
+
+ /* skip properties added automatically */
+ if (of_prop_cmp(rprop->name, "name") == 0)
+ continue;
+
+ err = of_property_read_string(root_sym,
+ rprop->name, &refpath);
+ if (err != 0) {
+ pr_err("%s: Could not find symbol '%s'\n",
+ __func__, rprop->name);
+ goto out;
+ }
+
+ refnode = of_find_node_by_path(refpath);
+ if (!refnode) {
+ pr_err("%s: Could not find node by path '%s'\n",
+ __func__, refpath);
+ err = -ENOENT;
+ goto out;
+ }
+
+ phandle = refnode->phandle;
+ of_node_put(refnode);
+
+ pr_debug("%s: %s phandle is 0x%08x\n",
+ __func__, rprop->name, phandle);
+
+ err = __of_adjust_phandle_ref(resolve, rprop, phandle, false);
+ if (err)
+ break;
+ }
+
+out:
+ /* NULL is handled by of_node_put as NOP */
+ of_node_put(root_sym);
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(of_resolve_phandles);
diff --git a/include/linux/of.h b/include/linux/of.h
index 6c4363b8ddc3..6545e7aec7bb 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -863,4 +863,7 @@ static inline int of_changeset_update_property(struct of_changeset *ocs,
}
#endif
+/* CONFIG_OF_RESOLVE api */
+extern int of_resolve_phandles(struct device_node *tree);
+
#endif /* _LINUX_OF_H */
--
1.9.1
--
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^ permalink raw reply related [flat|nested] 3+ messages in thread* [PATCH 2/2] of/selftest: Use the resolver to fixup phandles
[not found] ` <1412263624-21838-1-git-send-email-grant.likely-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
2014-10-02 15:27 ` [PATCH 1/2] OF: Introduce Device Tree resolve support Grant Likely
@ 2014-10-02 15:27 ` Grant Likely
1 sibling, 0 replies; 3+ messages in thread
From: Grant Likely @ 2014-10-02 15:27 UTC (permalink / raw)
To: devicetree-u79uwXL29TY76Z2rM5mHXA
Cc: Grant Likely, Pantelis Antoniou, Gaurav Minocha
The selftest data ends up causing duplicate phandles in the live tree
for the time that the testcase data is inserted into the live tree. This
is obviously a bad situation because anything attempting to read the
tree while the selftests are running make resolve phandles to one of the
testcase data nodes. Fix the problem by using the of_resolve_phandles()
function to eliminate duplicates.
Signed-off-by: Grant Likely <grant.likely-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
Cc: Pantelis Antoniou <pantelis.antoniou-OWPKS81ov/FWk0Htik3J/w@public.gmane.org>
Cc: Gaurav Minocha <gaurav.minocha.os-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
drivers/of/Kconfig | 1 +
drivers/of/selftest.c | 9 ++++++++-
drivers/of/testcase-data/testcases.dts | 35 ++++++++++++++++++++++++++++++++++
3 files changed, 44 insertions(+), 1 deletion(-)
diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
index 6b81a36f6420..1a13f5b722c5 100644
--- a/drivers/of/Kconfig
+++ b/drivers/of/Kconfig
@@ -11,6 +11,7 @@ config OF_SELFTEST
bool "Device Tree Runtime self tests"
depends on OF_IRQ && OF_EARLY_FLATTREE
select OF_DYNAMIC
+ select OF_RESOLVE
help
This option builds in test cases for the device tree infrastructure
that are executed once at boot time, and the results dumped to the
diff --git a/drivers/of/selftest.c b/drivers/of/selftest.c
index 634eb79bfe47..c80cd6258b1e 100644
--- a/drivers/of/selftest.c
+++ b/drivers/of/selftest.c
@@ -25,7 +25,7 @@ static struct selftest_results {
int failed;
} selftest_results;
-#define NO_OF_NODES 2
+#define NO_OF_NODES 3
static struct device_node *nodes[NO_OF_NODES];
static int last_node_index;
static bool selftest_live_tree;
@@ -765,6 +765,7 @@ static int __init selftest_data_add(void)
extern uint8_t __dtb_testcases_begin[];
extern uint8_t __dtb_testcases_end[];
const int size = __dtb_testcases_end - __dtb_testcases_begin;
+ int rc;
if (!size) {
pr_warn("%s: No testcase data to attach; not running tests\n",
@@ -785,6 +786,12 @@ static int __init selftest_data_add(void)
pr_warn("%s: No tree to attach; not running tests\n", __func__);
return -ENODATA;
}
+ of_node_set_flag(selftest_data_node, OF_DETACHED);
+ rc = of_resolve_phandles(selftest_data_node);
+ if (rc) {
+ pr_err("%s: Failed to resolve phandles (rc=%i)\n", __func__, rc);
+ return -EINVAL;
+ }
if (!of_allnodes) {
/* enabling flag for removing nodes */
diff --git a/drivers/of/testcase-data/testcases.dts b/drivers/of/testcase-data/testcases.dts
index 219ef9324e9c..6994e15c24bf 100644
--- a/drivers/of/testcase-data/testcases.dts
+++ b/drivers/of/testcase-data/testcases.dts
@@ -13,3 +13,38 @@
#include "tests-interrupts.dtsi"
#include "tests-match.dtsi"
#include "tests-platform.dtsi"
+
+/*
+ * phandle fixup data - generated by dtc patches that aren't upstream.
+ * This data must be regenerated whenever phandle references are modified in
+ * the testdata tree.
+ *
+ * The format of this data may be subject to change. For the time being consider
+ * this a kernel-internal data format.
+ */
+/ { __local_fixups__ {
+ fixup = "/testcase-data/testcase-device2:interrupt-parent:0",
+ "/testcase-data/testcase-device1:interrupt-parent:0",
+ "/testcase-data/interrupts/interrupts-extended0:interrupts-extended:60",
+ "/testcase-data/interrupts/interrupts-extended0:interrupts-extended:52",
+ "/testcase-data/interrupts/interrupts-extended0:interrupts-extended:44",
+ "/testcase-data/interrupts/interrupts-extended0:interrupts-extended:36",
+ "/testcase-data/interrupts/interrupts-extended0:interrupts-extended:24",
+ "/testcase-data/interrupts/interrupts-extended0:interrupts-extended:8",
+ "/testcase-data/interrupts/interrupts-extended0:interrupts-extended:0",
+ "/testcase-data/interrupts/interrupts1:interrupt-parent:0",
+ "/testcase-data/interrupts/interrupts0:interrupt-parent:0",
+ "/testcase-data/interrupts/intmap1:interrupt-map:12",
+ "/testcase-data/interrupts/intmap0:interrupt-map:52",
+ "/testcase-data/interrupts/intmap0:interrupt-map:36",
+ "/testcase-data/interrupts/intmap0:interrupt-map:16",
+ "/testcase-data/interrupts/intmap0:interrupt-map:4",
+ "/testcase-data/phandle-tests/consumer-a:phandle-list-bad-args:12",
+ "/testcase-data/phandle-tests/consumer-a:phandle-list-bad-args:0",
+ "/testcase-data/phandle-tests/consumer-a:phandle-list:56",
+ "/testcase-data/phandle-tests/consumer-a:phandle-list:52",
+ "/testcase-data/phandle-tests/consumer-a:phandle-list:40",
+ "/testcase-data/phandle-tests/consumer-a:phandle-list:24",
+ "/testcase-data/phandle-tests/consumer-a:phandle-list:8",
+ "/testcase-data/phandle-tests/consumer-a:phandle-list:0";
+}; };
--
1.9.1
--
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^ permalink raw reply related [flat|nested] 3+ messages in thread