PM: EM: Add em.yaml and autogen files

Add a generic netlink spec in YAML format and autogenerate boilerplate
code using ynl-regen.sh to introduce a generic netlink for the energy
model. It allows a userspace program to read the performance domain and
its energy model. It notifies the userspace program when a performance
domain is created or deleted or its energy model is updated through a
multicast interface.

Specifically, it supports two commands:
  - EM_CMD_GET_PDS: Get the list of information for all performance
    domains.
  - EM_CMD_GET_PD_TABLE: Get the energy model table of a performance
    domain.

Also, it supports three notification events:
  - EM_CMD_PD_CREATED: When a performance domain is created.
  - EM_CMD_PD_DELETED: When a performance domain is deleted.
  - EM_CMD_PD_UPDATED: When the energy model table of a performance domain
    is updated.

Finally, update MAINTAINERS to include new files.

Signed-off-by: Changwoo Min <changwoo@igalia.com>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Link: https://patch.msgid.link/20251020220914.320832-4-changwoo@igalia.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

2 files changed, 71 insertions, 0 deletions

diff --git a/kernel/power/em_netlink_autogen.c b/kernel/power/em_netlink_autogen.c
new file mode 100644
index 000000000000..a7a09ab1d1c2
--- /dev/null
+++ b/kernel/power/em_netlink_autogen.c
@@ -0,0 +1,48 @@
+// SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)
+/* Do not edit directly, auto-generated from: */
+/*	Documentation/netlink/specs/em.yaml */
+/* YNL-GEN kernel source */
+
+#include <net/netlink.h>
+#include <net/genetlink.h>
+
+#include "em_netlink_autogen.h"
+
+#include <uapi/linux/energy_model.h>
+
+/* EM_CMD_GET_PD_TABLE - do */
+static const struct nla_policy em_get_pd_table_nl_policy[EM_A_PD_TABLE_PD_ID + 1] = {
+	[EM_A_PD_TABLE_PD_ID] = { .type = NLA_U32, },
+};
+
+/* Ops table for em */
+static const struct genl_split_ops em_nl_ops[] = {
+	{
+		.cmd	= EM_CMD_GET_PDS,
+		.doit	= em_nl_get_pds_doit,
+		.flags	= GENL_CMD_CAP_DO,
+	},
+	{
+		.cmd		= EM_CMD_GET_PD_TABLE,
+		.doit		= em_nl_get_pd_table_doit,
+		.policy		= em_get_pd_table_nl_policy,
+		.maxattr	= EM_A_PD_TABLE_PD_ID,
+		.flags		= GENL_CMD_CAP_DO,
+	},
+};
+
+static const struct genl_multicast_group em_nl_mcgrps[] = {
+	[EM_NLGRP_EVENT] = { "event", },
+};
+
+struct genl_family em_nl_family __ro_after_init = {
+	.name		= EM_FAMILY_NAME,
+	.version	= EM_FAMILY_VERSION,
+	.netnsok	= true,
+	.parallel_ops	= true,
+	.module		= THIS_MODULE,
+	.split_ops	= em_nl_ops,
+	.n_split_ops	= ARRAY_SIZE(em_nl_ops),
+	.mcgrps		= em_nl_mcgrps,
+	.n_mcgrps	= ARRAY_SIZE(em_nl_mcgrps),
+};
diff --git a/kernel/power/em_netlink_autogen.h b/kernel/power/em_netlink_autogen.h
new file mode 100644
index 000000000000..78ce609641f1
--- /dev/null
+++ b/kernel/power/em_netlink_autogen.h
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) */
+/* Do not edit directly, auto-generated from: */
+/*	Documentation/netlink/specs/em.yaml */
+/* YNL-GEN kernel header */
+
+#ifndef _LINUX_EM_GEN_H
+#define _LINUX_EM_GEN_H
+
+#include <net/netlink.h>
+#include <net/genetlink.h>
+
+#include <uapi/linux/energy_model.h>
+
+int em_nl_get_pds_doit(struct sk_buff *skb, struct genl_info *info);
+int em_nl_get_pd_table_doit(struct sk_buff *skb, struct genl_info *info);
+
+enum {
+	EM_NLGRP_EVENT,
+};
+
+extern struct genl_family em_nl_family;
+
+#endif /* _LINUX_EM_GEN_H */