From: Andrew Lunn <andrew@lunn.ch>
Date: Sun, 10 May 2020 21:12:36 +0200
Subject: net: ethtool: Add infrastructure for reporting cable test results
Patch-mainline: v5.8-rc1
Git-commit: 1dd3f212af30b42c90ba252c165f2f6d2ddf5230
References: bsc#1176447

Provide infrastructure for PHY drivers to report the cable test
results.  A netlink skb is associated to the phydev. Helpers will be
added which can add results to this skb. Once the test has finished
the results are sent to user space.

When netlink ethtool is not part of the kernel configuration stubs are
provided. It is also impossible to trigger a cable test, so the error
code returned by the alloc function is of no consequence.

v2:
Include the status complete in the netlink notification message

v4:
Replace -EINVAL with -EMSGSIZE

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Michal Kubecek <mkubecek@suse.cz>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/phy/phy.c           |   22 ++++++++++++++--
 include/linux/ethtool_netlink.h |   20 ++++++++++++++
 include/linux/phy.h             |    5 +++
 net/ethtool/cabletest.c         |   55 ++++++++++++++++++++++++++++++++++++++++
 4 files changed, 100 insertions(+), 2 deletions(-)

--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -22,6 +22,7 @@
 #include <linux/module.h>
 #include <linux/mii.h>
 #include <linux/ethtool.h>
+#include <linux/ethtool_netlink.h>
 #include <linux/phy.h>
 #include <linux/phy_led_triggers.h>
 #include <linux/sfp.h>
@@ -30,6 +31,9 @@
 #include <linux/io.h>
 #include <linux/uaccess.h>
 #include <linux/atomic.h>
+#include <net/netlink.h>
+#include <net/genetlink.h>
+#include <net/sock.h>
 
 #define PHY_STATE_TIME	HZ
 
@@ -452,6 +456,8 @@ static void phy_abort_cable_test(struct
 {
 	int err;
 
+	ethnl_cable_test_finished(phydev);
+
 	err = phy_init_hw(phydev);
 	if (err)
 		phydev_err(phydev, "Error while aborting cable test");
@@ -460,7 +466,7 @@ static void phy_abort_cable_test(struct
 int phy_start_cable_test(struct phy_device *phydev,
 			 struct netlink_ext_ack *extack)
 {
-	int err;
+	int err = -ENOMEM;
 
 	if (!(phydev->drv &&
 	      phydev->drv->cable_test_start &&
@@ -486,19 +492,30 @@ int phy_start_cable_test(struct phy_devi
 		goto out;
 	}
 
+	err = ethnl_cable_test_alloc(phydev);
+	if (err)
+		goto out;
+
 	/* Mark the carrier down until the test is complete */
 	phy_link_down(phydev, true);
 
 	err = phydev->drv->cable_test_start(phydev);
 	if (err) {
 		phy_link_up(phydev);
-		goto out;
+		goto out_free;
 	}
 
 	phydev->state = PHY_CABLETEST;
 
 	if (phy_polling_mode(phydev))
 		phy_trigger_machine(phydev);
+
+	mutex_unlock(&phydev->lock);
+
+	return 0;
+
+out_free:
+	ethnl_cable_test_free(phydev);
 out:
 	mutex_unlock(&phydev->lock);
 
@@ -961,6 +978,7 @@ void phy_state_machine(struct work_struc
 		}
 
 		if (finished) {
+			ethnl_cable_test_finished(phydev);
 			needs_aneg = true;
 			phydev->state = PHY_UP;
 		}
--- a/include/linux/ethtool_netlink.h
+++ b/include/linux/ethtool_netlink.h
@@ -14,4 +14,24 @@ enum ethtool_multicast_groups {
 	ETHNL_MCGRP_MONITOR,
 };
 
+struct phy_device;
+
+#if IS_ENABLED(CONFIG_ETHTOOL_NETLINK)
+int ethnl_cable_test_alloc(struct phy_device *phydev);
+void ethnl_cable_test_free(struct phy_device *phydev);
+void ethnl_cable_test_finished(struct phy_device *phydev);
+#else
+static inline int ethnl_cable_test_alloc(struct phy_device *phydev)
+{
+	return -ENOTSUPP;
+}
+
+static inline void ethnl_cable_test_free(struct phy_device *phydev)
+{
+}
+
+static inline void ethnl_cable_test_finished(struct phy_device *phydev)
+{
+}
+#endif /* IS_ENABLED(ETHTOOL_NETLINK) */
 #endif /* _LINUX_ETHTOOL_NETLINK_H_ */
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -443,6 +443,11 @@ struct phy_device {
 	/* For use by PHYs to maintain extra state */
 	void *priv;
 
+	/* Reporting cable test results */
+	struct sk_buff *skb;
+	void *ehdr;
+	struct nlattr *nest;
+
 	/* Interrupt and Polling infrastructure */
 	struct delayed_work state_queue;
 
--- a/net/ethtool/cabletest.c
+++ b/net/ethtool/cabletest.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0-only
 
 #include <linux/phy.h>
+#include <linux/ethtool_netlink.h>
 #include "netlink.h"
 #include "common.h"
 
@@ -52,3 +53,57 @@ out_dev_put:
 	dev_put(dev);
 	return ret;
 }
+
+int ethnl_cable_test_alloc(struct phy_device *phydev)
+{
+	int err = -ENOMEM;
+
+	phydev->skb = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
+	if (!phydev->skb)
+		goto out;
+
+	phydev->ehdr = ethnl_bcastmsg_put(phydev->skb,
+					  ETHTOOL_MSG_CABLE_TEST_NTF);
+	if (!phydev->ehdr) {
+		err = -EMSGSIZE;
+		goto out;
+	}
+
+	err = ethnl_fill_reply_header(phydev->skb, phydev->attached_dev,
+				      ETHTOOL_A_CABLE_TEST_NTF_HEADER);
+	if (err)
+		goto out;
+
+	err = nla_put_u8(phydev->skb, ETHTOOL_A_CABLE_TEST_NTF_STATUS,
+			 ETHTOOL_A_CABLE_TEST_NTF_STATUS_COMPLETED);
+	if (err)
+		goto out;
+
+	phydev->nest = nla_nest_start(phydev->skb,
+				      ETHTOOL_A_CABLE_TEST_NTF_NEST);
+	if (!phydev->nest)
+		goto out;
+
+	return 0;
+
+out:
+	nlmsg_free(phydev->skb);
+	return err;
+}
+EXPORT_SYMBOL_GPL(ethnl_cable_test_alloc);
+
+void ethnl_cable_test_free(struct phy_device *phydev)
+{
+	nlmsg_free(phydev->skb);
+}
+EXPORT_SYMBOL_GPL(ethnl_cable_test_free);
+
+void ethnl_cable_test_finished(struct phy_device *phydev)
+{
+	nla_nest_end(phydev->skb, phydev->nest);
+
+	genlmsg_end(phydev->skb, phydev->ehdr);
+
+	ethnl_multicast(phydev->skb, phydev->attached_dev);
+}
+EXPORT_SYMBOL_GPL(ethnl_cable_test_finished);