[02/11] PM: EM: Add a skeleton code for netlink notification.

diff --git a/include/uapi/linux/energy_model.h b/include/uapi/linux/energy_model.h
new file mode 100644
index 000000000000..42a19e614c7d
--- /dev/null
+++ b/include/uapi/linux/energy_model.h
@@ -0,0 +1,40 @@ 
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+#ifndef _UAPI_LINUX_ENERGY_MODEL_H
+#define _UAPI_LINUX_ENERGY_MODEL_H
+
+/* Adding event notification support elements */
+#define EM_GENL_FAMILY_NAME		"energy_model"
+#define EM_GENL_VERSION			0x01
+#define EM_GENL_EVENT_GROUP_NAME	"event"
+
+/* Attributes of em_genl_family */
+enum em_genl_attr {
+	EM_GENL_ATTR_UNSPEC,
+	__EM_GENL_ATTR_MAX,
+};
+#define EM_GENL_ATTR_MAX (__EM_GENL_ATTR_MAX - 1)
+
+/* Events of em_genl_family */
+enum em_genl_event {
+	EM_GENL_EVENT_UNSPEC,
+	EM_GENL_EVENT_PD_CREATE,	/* Performance domain creation */
+	EM_GENL_EVENT_PD_DELETE,	/* Performance domain deletion */
+	EM_GENL_EVENT_PD_UPDATE,	/* The runtime EM table for the
+					   performance domain is updated */
+	__EM_GENL_EVENT_MAX,
+};
+#define EM_GENL_EVENT_MAX (__EM_GENL_EVENT_MAX - 1)
+
+/* Commands supported by the em_genl_family */
+enum em_genl_cmd {
+	EM_GENL_CMD_UNSPEC,
+	EM_GENL_CMD_PD_GET_ID,		/* Get the list of information
+					   for all performance domains */
+	EM_GENL_CMD_PD_GET_TBL,		/* Get the energy model table
+					   of a performance domain */
+	__EM_GENL_CMD_MAX,
+};
+#define EM_GENL_CMD_MAX (__EM_GENL_CMD_MAX - 1)
+
+
+#endif /* _UAPI_LINUX_ENERGY_MODEL_H */
diff --git a/kernel/power/Makefile b/kernel/power/Makefile
index 874ad834dc8d..6bf157b5fffd 100644
--- a/kernel/power/Makefile
+++ b/kernel/power/Makefile
@@ -22,3 +22,4 @@  obj-$(CONFIG_PM_WAKELOCKS)	+= wakelock.o
 obj-$(CONFIG_MAGIC_SYSRQ)	+= poweroff.o
 
 obj-$(CONFIG_ENERGY_MODEL)	+= energy_model.o
+obj-$(CONFIG_ENERGY_MODEL_NETLINK) += em_netlink.o
diff --git a/kernel/power/em_netlink.c b/kernel/power/em_netlink.c
new file mode 100644
index 000000000000..30d83fb5a3a8
--- /dev/null
+++ b/kernel/power/em_netlink.c
@@ -0,0 +1,69 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *
+ * Generic netlink for energy model.
+ *
+ * Copyright (c) 2025 Valve Corporation.
+ * Author: Changwoo Min <changwoo@igalia.com>
+ */
+
+#define pr_fmt(fmt) "energy_model: " fmt
+
+#include <linux/energy_model.h>
+#include <net/sock.h>
+#include <net/genetlink.h>
+#include <uapi/linux/energy_model.h>
+
+#include "em_netlink.h"
+
+static const struct genl_multicast_group em_genl_mcgrps[] = {
+	[EM_GENL_EVENT_GROUP]  = { .name = EM_GENL_EVENT_GROUP_NAME,  },
+};
+
+static const struct nla_policy em_genl_policy[EM_GENL_ATTR_MAX + 1] = {
+};
+
+static struct genl_family em_genl_family;
+
+
+static int em_genl_cmd_doit(struct sk_buff *skb, struct genl_info *info)
+{
+	return -ENOTSUPP;
+}
+
+static const struct genl_small_ops em_genl_ops[] = {
+	{
+		.cmd = EM_GENL_CMD_PD_GET_ID,
+		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
+		.doit = em_genl_cmd_doit,
+	},
+	{
+		.cmd = EM_GENL_CMD_PD_GET_TBL,
+		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
+		.doit = em_genl_cmd_doit,
+	},
+};
+
+static struct genl_family em_genl_family __ro_after_init = {
+	.hdrsize	= 0,
+	.name		= EM_GENL_FAMILY_NAME,
+	.version	= EM_GENL_VERSION,
+	.maxattr	= EM_GENL_ATTR_MAX,
+	.policy		= em_genl_policy,
+	.small_ops	= em_genl_ops,
+	.n_small_ops	= ARRAY_SIZE(em_genl_ops),
+	.resv_start_op	= __EM_GENL_CMD_MAX,
+	.mcgrps		= em_genl_mcgrps,
+	.n_mcgrps	= ARRAY_SIZE(em_genl_mcgrps),
+};
+
+int __init em_netlink_init(void)
+{
+	return genl_register_family(&em_genl_family);
+}
+
+void __init em_netlink_exit(void)
+{
+	genl_unregister_family(&em_genl_family);
+}
+
diff --git a/kernel/power/em_netlink.h b/kernel/power/em_netlink.h
new file mode 100644
index 000000000000..8cedc6495916
--- /dev/null
+++ b/kernel/power/em_netlink.h
@@ -0,0 +1,26 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *
+ * Generic netlink for energy model.
+ *
+ * Copyright (c) 2025 Valve Corporation.
+ * Author: Changwoo Min <changwoo@igalia.com>
+ */
+
+enum em_genl_multicast_groups {
+	EM_GENL_EVENT_GROUP = 0,
+	EM_GENL_MAX_GROUP = EM_GENL_EVENT_GROUP,
+};
+
+/* Netlink notification function */
+#ifdef CONFIG_ENERGY_MODEL_NETLINK
+int __init em_netlink_init(void);
+void __init em_netlink_exit(void);
+#else
+static inline int em_netlink_init(void)
+{
+	return 0;
+}
+
+static inline void em_netlink_exit(void) {}
+#endif /* CONFIG_ENERGY_MODEL_NETLINK */