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From:   Lizhi Hou <lizhi.hou@amd.com>
To:     <linux-pci@vger.kernel.org>, <devicetree@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <robh@kernel.org>
CC:     Lizhi Hou <lizhi.hou@amd.com>, <max.zhen@amd.com>,
        <sonal.santan@amd.com>, <stefano.stabellini@xilinx.com>,
        =?UTF-8?q?Cl=C3=A9ment=20L=C3=A9ger?= <clement.leger@bootlin.com>
Subject: [PATCH V10 1/5] of: dynamic: Add interfaces for creating device node dynamically
Date:   Thu, 29 Jun 2023 10:19:46 -0700
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of_changeset_create_node() creates device node dynamically and attaches
the newly created node to a changeset.

Expand of_changeset APIs to handle specific types of properties.
    of_changeset_add_empty_prop()
    of_changeset_add_prop_string()
    of_changeset_add_prop_string_array()
    of_changeset_add_prop_u32_array()

Signed-off-by: Clément Léger <clement.leger@bootlin.com>
Signed-off-by: Lizhi Hou <lizhi.hou@amd.com>
---
 drivers/of/dynamic.c  | 187 ++++++++++++++++++++++++++++++++++++++++++
 drivers/of/unittest.c |  19 ++++-
 include/linux/of.h    |  26 ++++++
 3 files changed, 231 insertions(+), 1 deletion(-)

diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c
index e311d406b170..4d0720a09be7 100644
--- a/drivers/of/dynamic.c
+++ b/drivers/of/dynamic.c
@@ -487,6 +487,38 @@ struct device_node *__of_node_dup(const struct device_node *np,
 	return NULL;
 }
 
+/**
+ * of_changeset_create_node - Dynamically create a device node and attach to
+ * a given changeset.
+ *
+ * @parent: Pointer to parent device node
+ * @full_name: Node full name
+ * @cset: Pointer to changeset
+ *
+ * Return: Pointer to the created device node or NULL in case of an error.
+ */
+struct device_node *of_changeset_create_node(struct device_node *parent,
+					     const char *full_name,
+					     struct of_changeset *cset)
+{
+	struct device_node *np;
+	int ret;
+
+	np = __of_node_dup(NULL, full_name);
+	if (!np)
+		return NULL;
+	np->parent = parent;
+
+	ret = of_changeset_attach_node(cset, np);
+	if (ret) {
+		of_node_put(np);
+		return NULL;
+	}
+
+	return np;
+}
+EXPORT_SYMBOL(of_changeset_create_node);
+
 static void __of_changeset_entry_destroy(struct of_changeset_entry *ce)
 {
 	if (ce->action == OF_RECONFIG_ATTACH_NODE &&
@@ -960,3 +992,158 @@ int of_changeset_action(struct of_changeset *ocs, unsigned long action,
 	return 0;
 }
 EXPORT_SYMBOL_GPL(of_changeset_action);
+
+static int of_changeset_add_prop_helper(struct of_changeset *ocs,
+					struct device_node *np,
+					const struct property *pp)
+{
+	struct property *new_pp;
+	int ret;
+
+	new_pp = __of_prop_dup(pp, GFP_KERNEL);
+	if (!new_pp)
+		return -ENOMEM;
+
+	ret = of_changeset_add_property(ocs, np, new_pp);
+	if (ret) {
+		kfree(new_pp->name);
+		kfree(new_pp->value);
+		kfree(new_pp);
+	}
+
+	return ret;
+}
+
+/**
+ * of_changeset_add_empty_prop - Add an empty property to a changeset
+ *
+ * @ocs:	changeset pointer
+ * @np:		device node pointer
+ * @prop_name:	name of the property to be added
+ *
+ * Create an empty property and add it to a changeset.
+ *
+ * Return: 0 on success, a negative error value in case of an error.
+ */
+int of_changeset_add_empty_prop(struct of_changeset *ocs,
+				struct device_node *np,
+				const char *prop_name)
+{
+	struct property prop = { 0 };
+
+	prop.name = (char *)prop_name;
+
+	return of_changeset_add_prop_helper(ocs, np, &prop);
+}
+EXPORT_SYMBOL_GPL(of_changeset_add_empty_prop);
+
+/**
+ * of_changeset_add_prop_string - Add a string property to a changeset
+ *
+ * @ocs:	changeset pointer
+ * @np:		device node pointer
+ * @prop_name:	name of the property to be added
+ * @str:	pointer to null terminated string
+ *
+ * Create a string property and add it to a changeset.
+ *
+ * Return: 0 on success, a negative error value in case of an error.
+ */
+int of_changeset_add_prop_string(struct of_changeset *ocs,
+				 struct device_node *np,
+				 const char *prop_name, const char *str)
+{
+	struct property prop;
+
+	prop.name = (char *)prop_name;
+	prop.length = strlen(str) + 1;
+	prop.value = (void *)str;
+
+	return of_changeset_add_prop_helper(ocs, np, &prop);
+}
+EXPORT_SYMBOL_GPL(of_changeset_add_prop_string);
+
+/**
+ * of_changeset_add_prop_string_array - Add a string list property to
+ * a changeset
+ *
+ * @ocs:	changeset pointer
+ * @np:		device node pointer
+ * @prop_name:	name of the property to be added
+ * @str_array:	pointer to an array of null terminated strings
+ * @sz:		number of string array elements
+ *
+ * Create a string list property and add it to a changeset.
+ *
+ * Return: 0 on success, a negative error value in case of an error.
+ */
+int of_changeset_add_prop_string_array(struct of_changeset *ocs,
+				       struct device_node *np,
+				       const char *prop_name,
+				       const char **str_array, size_t sz)
+{
+	struct property prop;
+	int i, ret;
+	char *vp;
+
+	prop.name = (char *)prop_name;
+
+	prop.length = 0;
+	for (i = 0; i < sz; i++)
+		prop.length += strlen(str_array[i]) + 1;
+
+	prop.value = kmalloc(prop.length, GFP_KERNEL);
+	if (!prop.value)
+		return -ENOMEM;
+
+	vp = prop.value;
+	for (i = 0; i < sz; i++) {
+		vp += snprintf(vp, (char *)prop.value + prop.length - vp, "%s",
+			       str_array[i]) + 1;
+	}
+	ret = of_changeset_add_prop_helper(ocs, np, &prop);
+	kfree(prop.value);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(of_changeset_add_prop_string_array);
+
+/**
+ * of_changeset_add_prop_u32_array - Add a property of 32 bit integers
+ * property to a changeset
+ *
+ * @ocs:	changeset pointer
+ * @np:		device node pointer
+ * @prop_name:	name of the property to be added
+ * @array:	pointer to an array of 32 bit integers
+ * @sz:		number of array elements
+ *
+ * Create a property of 32 bit integers and add it to a changeset.
+ *
+ * Return: 0 on success, a negative error value in case of an error.
+ */
+int of_changeset_add_prop_u32_array(struct of_changeset *ocs,
+				    struct device_node *np,
+				    const char *prop_name,
+				    const u32 *array, size_t sz)
+{
+	struct property prop;
+	__be32 *val;
+	int i, ret;
+
+	val = kcalloc(sz, sizeof(__be32), GFP_KERNEL);
+	if (!val)
+		return -ENOMEM;
+
+	for (i = 0; i < sz; i++)
+		val[i] = cpu_to_be32(array[i]);
+	prop.name = (char *)prop_name;
+	prop.length = sizeof(u32) * sz;
+	prop.value = (void *)val;
+
+	ret = of_changeset_add_prop_helper(ocs, np, &prop);
+	kfree(val);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(of_changeset_add_prop_u32_array);
diff --git a/drivers/of/unittest.c b/drivers/of/unittest.c
index 2191c0136531..1193a574fa36 100644
--- a/drivers/of/unittest.c
+++ b/drivers/of/unittest.c
@@ -802,7 +802,9 @@ static void __init of_unittest_changeset(void)
 	struct property *ppname_n21, pname_n21 = { .name = "name", .length = 3, .value = "n21" };
 	struct property *ppupdate, pupdate = { .name = "prop-update", .length = 5, .value = "abcd" };
 	struct property *ppremove;
-	struct device_node *n1, *n2, *n21, *nchangeset, *nremove, *parent, *np;
+	struct device_node *n1, *n2, *n21, *n22, *nchangeset, *nremove, *parent, *np;
+	static const char * const str_array[] = { "str1", "str2", "str3" };
+	const u32 u32_array[] = { 1, 2, 3 };
 	struct of_changeset chgset;
 
 	n1 = __of_node_dup(NULL, "n1");
@@ -857,6 +859,17 @@ static void __init of_unittest_changeset(void)
 	unittest(!of_changeset_add_property(&chgset, parent, ppadd), "fail add prop prop-add\n");
 	unittest(!of_changeset_update_property(&chgset, parent, ppupdate), "fail update prop\n");
 	unittest(!of_changeset_remove_property(&chgset, parent, ppremove), "fail remove prop\n");
+	n22 = of_changeset_create_node(n2, "n22", &chgset);
+	unittest(n22, "fail create n22\n");
+	unittest(!of_changeset_add_prop_string(&chgset, n22, "prop-str", "abcd"),
+		 "fail add prop prop-str");
+	unittest(!of_changeset_add_prop_string_array(&chgset, n22, "prop-str-array",
+						     (const char **)str_array,
+						     ARRAY_SIZE(str_array)),
+		 "fail add prop prop-str-array");
+	unittest(!of_changeset_add_prop_u32_array(&chgset, n22, "prop-u32-array",
+						  u32_array, ARRAY_SIZE(u32_array)),
+		 "fail add prop prop-u32-array");
 
 	unittest(!of_changeset_apply(&chgset), "apply failed\n");
 
@@ -866,6 +879,9 @@ static void __init of_unittest_changeset(void)
 	unittest((np = of_find_node_by_path("/testcase-data/changeset/n2/n21")),
 		 "'%pOF' not added\n", n21);
 	of_node_put(np);
+	unittest((np = of_find_node_by_path("/testcase-data/changeset/n2/n22")),
+		 "'%pOF' not added\n", n22);
+	of_node_put(np);
 
 	unittest(!of_changeset_revert(&chgset), "revert failed\n");
 
@@ -874,6 +890,7 @@ static void __init of_unittest_changeset(void)
 	of_node_put(n1);
 	of_node_put(n2);
 	of_node_put(n21);
+	of_node_put(n22);
 #endif
 }
 
diff --git a/include/linux/of.h b/include/linux/of.h
index 6ecde0515677..703152181a44 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -1580,6 +1580,32 @@ static inline int of_changeset_update_property(struct of_changeset *ocs,
 {
 	return of_changeset_action(ocs, OF_RECONFIG_UPDATE_PROPERTY, np, prop);
 }
+
+struct device_node *of_changeset_create_node(struct device_node *parent,
+					     const char *full_name,
+					     struct of_changeset *cset);
+int of_changeset_add_empty_prop(struct of_changeset *ocs,
+				struct device_node *np,
+				const char *prop_name);
+int of_changeset_add_prop_string(struct of_changeset *ocs,
+				 struct device_node *np,
+				 const char *prop_name, const char *str);
+int of_changeset_add_prop_string_array(struct of_changeset *ocs,
+				       struct device_node *np,
+				       const char *prop_name,
+				       const char **str_array, size_t sz);
+int of_changeset_add_prop_u32_array(struct of_changeset *ocs,
+				    struct device_node *np,
+				    const char *prop_name,
+				    const u32 *array, size_t sz);
+static inline int of_changeset_add_prop_u32(struct of_changeset *ocs,
+					    struct device_node *np,
+					    const char *prop_name,
+					    const u32 val)
+{
+	return of_changeset_add_prop_u32_array(ocs, np, prop_name, &val, 1);
+}
+
 #else /* CONFIG_OF_DYNAMIC */
 static inline int of_reconfig_notifier_register(struct notifier_block *nb)
 {
-- 
2.34.1