[RFC PATCH v1 2/3] dpll: add netlink events

[Vadim Fedorenko]

From: Vadim Fedorenko <vadfed at fb.com>

Add netlink interface to enable notification of users about
events in DPLL framework. Part of this interface should be
used by drivers directly, i.e. lock status changes.

Signed-off-by: Vadim Fedorenko <vadfed at fb.com>
---
 drivers/dpll/dpll_core.c    |   2 +
 drivers/dpll/dpll_netlink.c | 141 ++++++++++++++++++++++++++++++++++++
 drivers/dpll/dpll_netlink.h |   7 ++
 3 files changed, 150 insertions(+)

diff --git a/drivers/dpll/dpll_core.c b/drivers/dpll/dpll_core.c
index e34767e723cf..6be169df3c9e 100644
--- a/drivers/dpll/dpll_core.c
+++ b/drivers/dpll/dpll_core.c
@@ -99,6 +99,8 @@ struct dpll_device *dpll_device_alloc(struct dpll_device_ops *ops, int sources_c
 	mutex_unlock(&dpll_device_xa_lock);
 	dpll->priv = priv;
 
+	dpll_notify_device_create(dpll->id, dev_name(&dpll->dev));
+
 	return dpll;
 
 error:
diff --git a/drivers/dpll/dpll_netlink.c b/drivers/dpll/dpll_netlink.c
index 0bbdaa6dde8e..6c1dd4ce1f89 100644
--- a/drivers/dpll/dpll_netlink.c
+++ b/drivers/dpll/dpll_netlink.c
@@ -48,6 +48,8 @@ struct param {
 	int dpll_source_type;
 	int dpll_output_id;
 	int dpll_output_type;
+	int dpll_status;
+	const char *dpll_name;
 };
 
 struct dpll_dump_ctx {
@@ -222,6 +224,8 @@ static int dpll_genl_cmd_set_source(struct param *p)
 	ret = dpll->ops->set_source_type(dpll, src_id, type);
 	mutex_unlock(&dpll->lock);
 
+	dpll_notify_source_change(dpll->id, src_id, type);
+
 	return ret;
 }
 
@@ -245,6 +249,8 @@ static int dpll_genl_cmd_set_output(struct param *p)
 	ret = dpll->ops->set_source_type(dpll, out_id, type);
 	mutex_unlock(&dpll->lock);
 
+	dpll_notify_source_change(dpll->id, out_id, type);
+
 	return ret;
 }
 
@@ -421,6 +427,141 @@ static struct genl_family dpll_gnl_family __ro_after_init = {
 	.pre_doit	= dpll_pre_doit,
 };
 
+static int dpll_event_device_create(struct param *p)
+{
+	if (nla_put_u32(p->msg, DPLLA_DEVICE_ID, p->dpll_id) ||
+	    nla_put_string(p->msg, DPLLA_DEVICE_NAME, p->dpll_name))
+		return -EMSGSIZE;
+
+	return 0;
+}
+
+static int dpll_event_device_delete(struct param *p)
+{
+	if (nla_put_u32(p->msg, DPLLA_DEVICE_ID, p->dpll_id))
+		return -EMSGSIZE;
+
+	return 0;
+}
+
+static int dpll_event_status(struct param *p)
+{
+	if (nla_put_u32(p->msg, DPLLA_DEVICE_ID, p->dpll_id) ||
+		nla_put_u32(p->msg, DPLLA_LOCK_STATUS, p->dpll_status))
+		return -EMSGSIZE;
+
+	return 0;
+}
+
+static int dpll_event_source_change(struct param *p)
+{
+	if (nla_put_u32(p->msg, DPLLA_DEVICE_ID, p->dpll_id) ||
+	    nla_put_u32(p->msg, DPLLA_SOURCE_ID, p->dpll_source_id) ||
+		nla_put_u32(p->msg, DPLLA_SOURCE_TYPE, p->dpll_source_type))
+		return -EMSGSIZE;
+
+	return 0;
+}
+
+static int dpll_event_output_change(struct param *p)
+{
+	if (nla_put_u32(p->msg, DPLLA_DEVICE_ID, p->dpll_id) ||
+	    nla_put_u32(p->msg, DPLLA_OUTPUT_ID, p->dpll_output_id) ||
+		nla_put_u32(p->msg, DPLLA_OUTPUT_TYPE, p->dpll_output_type))
+		return -EMSGSIZE;
+
+	return 0;
+}
+
+static cb_t event_cb[] = {
+	[DPLL_EVENT_DEVICE_CREATE]	= dpll_event_device_create,
+	[DPLL_EVENT_DEVICE_DELETE]	= dpll_event_device_delete,
+	[DPLL_EVENT_STATUS_LOCKED]	= dpll_event_status,
+	[DPLL_EVENT_STATUS_UNLOCKED]	= dpll_event_status,
+	[DPLL_EVENT_SOURCE_CHANGE]	= dpll_event_source_change,
+	[DPLL_EVENT_OUTPUT_CHANGE]	= dpll_event_output_change,
+};
+/*
+ * Generic netlink DPLL event encoding
+ */
+static int dpll_send_event(enum dpll_genl_event event,
+				   struct param *p)
+{
+	struct sk_buff *msg;
+	int ret = -EMSGSIZE;
+	void *hdr;
+
+	msg = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+	p->msg = msg;
+
+	hdr = genlmsg_put(msg, 0, 0, &dpll_gnl_family, 0, event);
+	if (!hdr)
+		goto out_free_msg;
+
+	ret = event_cb[event](p);
+	if (ret)
+		goto out_cancel_msg;
+
+	genlmsg_end(msg, hdr);
+
+	genlmsg_multicast(&dpll_gnl_family, msg, 0, 1, GFP_KERNEL);
+
+	return 0;
+
+out_cancel_msg:
+	genlmsg_cancel(msg, hdr);
+out_free_msg:
+	nlmsg_free(msg);
+
+	return ret;
+}
+
+int dpll_notify_device_create(int dpll_id, const char *name)
+{
+	struct param p = { .dpll_id = dpll_id, .dpll_name = name };
+
+	return dpll_send_event(DPLL_EVENT_DEVICE_CREATE, &p);
+}
+
+int dpll_notify_device_delete(int dpll_id)
+{
+	struct param p = { .dpll_id = dpll_id };
+
+	return dpll_send_event(DPLL_EVENT_DEVICE_DELETE, &p);
+}
+
+int dpll_notify_status_locked(int dpll_id)
+{
+	struct param p = { .dpll_id = dpll_id, .dpll_status = 1 };
+
+	return dpll_send_event(DPLL_EVENT_STATUS_LOCKED, &p);
+}
+
+int dpll_notify_status_unlocked(int dpll_id)
+{
+	struct param p = { .dpll_id = dpll_id, .dpll_status = 0 };
+
+	return dpll_send_event(DPLL_EVENT_STATUS_UNLOCKED, &p);
+}
+
+int dpll_notify_source_change(int dpll_id, int source_id, int source_type)
+{
+	struct param p =  { .dpll_id = dpll_id, .dpll_source_id = source_id,
+						.dpll_source_type = source_type };
+
+	return dpll_send_event(DPLL_EVENT_SOURCE_CHANGE, &p);
+}
+
+int dpll_notify_output_change(int dpll_id, int output_id, int output_type)
+{
+	struct param p =  { .dpll_id = dpll_id, .dpll_output_id = output_id,
+						.dpll_output_type = output_type };
+
+	return dpll_send_event(DPLL_EVENT_OUTPUT_CHANGE, &p);
+}
+
 int __init dpll_netlink_init(void)
 {
 	return genl_register_family(&dpll_gnl_family);
diff --git a/drivers/dpll/dpll_netlink.h b/drivers/dpll/dpll_netlink.h
index e2d100f59dd6..0dc81320f982 100644
--- a/drivers/dpll/dpll_netlink.h
+++ b/drivers/dpll/dpll_netlink.h
@@ -3,5 +3,12 @@
  *  Copyright (c) 2021 Meta Platforms, Inc. and affiliates
  */
 
+int dpll_notify_device_create(int dpll_id, const char *name);
+int dpll_notify_device_delete(int dpll_id);
+int dpll_notify_status_locked(int dpll_id);
+int dpll_notify_status_unlocked(int dpll_id);
+int dpll_notify_source_change(int dpll_id, int source_id, int source_type);
+int dpll_notify_output_change(int dpll_id, int output_id, int output_type);
+
 int __init dpll_netlink_init(void);
 void dpll_netlink_finish(void);
-- 
2.27.0