Add new ethtool netlink calls to trigger the starting of a PHY cable
test.

Add Kconfig'ury to ETHTOOL_NETLINK so that PHYLIB is not a module when
ETHTOOL_NETLINK is builtin, which would result in kernel linking errors.

v2:
Remove unwanted white space change
Remove ethnl_cable_test_act_ops and use doit handler
Rename cable_test_set_policy cable_test_act_policy
Remove ETHTOOL_MSG_CABLE_TEST_ACT_REPLY

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
---

diff --git a/Documentation/networking/ethtool-netlink.rst b/Documentation/networking/ethtool-netlink.rst
index 567326491f80..72d53da2bea9 100644
--- a/Documentation/networking/ethtool-netlink.rst
+++ b/Documentation/networking/ethtool-netlink.rst

@@ -204,6 +204,7 @@ Userspace to kernel:
   ``ETHTOOL_MSG_EEE_GET``               get EEE settings
   ``ETHTOOL_MSG_EEE_SET``               set EEE settings
   ``ETHTOOL_MSG_TSINFO_GET``		get timestamping info
+  ``ETHTOOL_MSG_CABLE_TEST_ACT``        action start cable test
   ===================================== ================================
 
 Kernel to userspace:

@@ -235,6 +236,7 @@ Kernel to userspace:
   ``ETHTOOL_MSG_EEE_GET_REPLY``         EEE settings
   ``ETHTOOL_MSG_EEE_NTF``               EEE settings
   ``ETHTOOL_MSG_TSINFO_GET_REPLY``	timestamping info
+  ``ETHTOOL_MSG_CABLE_TEST_ACT_REPLY``  Cable test action result

diff --git a/net/ethtool/cabletest.c b/net/ethtool/cabletest.c
new file mode 100644
index 000000000000..6e5782a7da80
--- /dev/null
+++ b/net/ethtool/cabletest.c

@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/phy.h>
+#include "netlink.h"
+#include "common.h"
+#include "bitset.h"
+
+static const struct nla_policy
+cable_test_get_policy[ETHTOOL_A_CABLE_TEST_MAX + 1] = {
+	[ETHTOOL_A_CABLE_TEST_UNSPEC]		= { .type = NLA_REJECT },
+	[ETHTOOL_A_CABLE_TEST_HEADER]		= { .type = NLA_NESTED },
+};

diff --git a/net/ethtool/netlink.h b/net/ethtool/netlink.h
index 81b8fa020bcb..03e65e2b9e3d 100644
--- a/net/ethtool/netlink.h
+++ b/net/ethtool/netlink.h

@@ -345,6 +345,7 @@ extern const struct ethnl_request_ops ethnl_coalesce_request_ops;
 extern const struct ethnl_request_ops ethnl_pause_request_ops;
 extern const struct ethnl_request_ops ethnl_eee_request_ops;
 extern const struct ethnl_request_ops ethnl_tsinfo_request_ops;
+extern const struct ethnl_request_ops ethnl_cable_test_act_ops;