[PATCH net-next v3 3/3] selftests: ethtool: Introduce ethernet PHY selftests on netdevsim

[Maxime Chevallier <maxime.chevallier@bootlin.com>]

Now that netdevsim supports PHY device simulation, we can start writing
some tests to cover a little bit all PHY-related ethtool commands.

So far we only test the basic use of "ethtool --show-phys", with :
 - A simple command to get a PHY we just added
 - A DUMP command listing PHYs on multiple netdevsim instances
 - A Filtered DUMP command listing all PHYs on a netdevsim

Introduce some helpers to create netdevsim PHYs, and a new test file.

Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
---
 .../selftests/drivers/net/netdevsim/config    |  1 +
 .../drivers/net/netdevsim/ethtool-common.sh   | 15 +++++
 .../drivers/net/netdevsim/ethtool-phy.sh      | 64 +++++++++++++++++++
 3 files changed, 80 insertions(+)
 create mode 100755 tools/testing/selftests/drivers/net/netdevsim/ethtool-phy.sh

diff --git a/tools/testing/selftests/drivers/net/netdevsim/config b/tools/testing/selftests/drivers/net/netdevsim/config
index 5117c78ddf0a..223e82cb7759 100644
--- a/tools/testing/selftests/drivers/net/netdevsim/config
+++ b/tools/testing/selftests/drivers/net/netdevsim/config
@@ -6,6 +6,7 @@ CONFIG_NETDEVSIM=m
 CONFIG_NET_SCH_MQPRIO=y
 CONFIG_NET_SCH_MULTIQ=y
 CONFIG_NET_SCH_PRIO=y
+CONFIG_PHYLIB=m
 CONFIG_PSAMPLE=y
 CONFIG_PTP_1588_CLOCK_MOCK=y
 CONFIG_VXLAN=m
diff --git a/tools/testing/selftests/drivers/net/netdevsim/ethtool-common.sh b/tools/testing/selftests/drivers/net/netdevsim/ethtool-common.sh
index d9c7a3d397a9..1bd0ac5e7bba 100644
--- a/tools/testing/selftests/drivers/net/netdevsim/ethtool-common.sh
+++ b/tools/testing/selftests/drivers/net/netdevsim/ethtool-common.sh
@@ -53,3 +53,18 @@ function make_netdev {
     # get new device name
     ls /sys/bus/netdevsim/devices/netdevsim${NSIM_ID}/net/
 }
+
+function make_phydev_on_netdev {
+    local parent_ndev_nsim_id=$1
+    local parent=$2
+
+    local ndev_dfs=/sys/kernel/debug/netdevsim/netdevsim$parent_ndev_nsim_id/ports/0
+
+    old_dev_dfs=$(find $ndev_dfs -type d)
+    echo $parent > $ndev_dfs/phy_add
+    new_dev_dfs=$(find $ndev_dfs -type d)
+
+    # The new phydev name corresponds to the new file that was created. Its
+    # name isn't predictable.
+    echo $old_dev_dfs $new_dev_dfs | xargs -n1 | sort  | uniq -u
+}
diff --git a/tools/testing/selftests/drivers/net/netdevsim/ethtool-phy.sh b/tools/testing/selftests/drivers/net/netdevsim/ethtool-phy.sh
new file mode 100755
index 000000000000..b10440d108b2
--- /dev/null
+++ b/tools/testing/selftests/drivers/net/netdevsim/ethtool-phy.sh
@@ -0,0 +1,64 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0-only
+
+source ethtool-common.sh
+
+# Bail if ethtool is too old
+if ! ethtool -h | grep show-phys >/dev/null 2>&1; then
+    echo "SKIP: No --show-phys support in ethtool"
+    exit 4
+fi
+
+function make_netdev_from_id {
+    local new_nsim_id="$1"
+    # Make a netdevsim
+    echo "$new_nsim_id" > /sys/bus/netdevsim/new_device
+    udevadm settle
+    # get new device name
+    ls /sys/bus/netdevsim/devices/netdevsim"${new_nsim_id}"/net/
+}
+
+function cleanup_netdev_from_id {
+    local to_del_nsim_id="$1"
+    echo "$to_del_nsim_id" > /sys/bus/netdevsim/del_device
+}
+
+NSIM_NETDEV=$(make_netdev)
+
+set -o pipefail
+
+# Check simple PHY addition and listing
+
+# Parent == 0 means that the PHY's parent is the netdev
+PHY_DFS=$(make_phydev_on_netdev "$NSIM_ID" 0)
+
+# First PHY gets index 1
+index=$(ethtool --show-phys "$NSIM_NETDEV" | grep "PHY index" | cut -d ' ' -f 3)
+check $? "$index" "1"
+
+# Insert a second PHY, same parent. It gets index 2.
+PHY2_DFS=$(make_phydev_on_netdev "$NSIM_ID" 0)
+
+# Create another netdev
+NSIM_ID2=$((RANDOM % 1024))
+NSIM_NETDEV_2=$(make_netdev_from_id "$NSIM_ID2")
+
+PHY3_DFS=$(make_phydev_on_netdev "$NSIM_ID2" 0);
+
+# Check unfiltered PHY Dump
+n_phy=$(ethtool --show-phys '*' | grep -c "PHY index")
+check $? "$n_phy" "3"
+
+# Check filtered Dump
+n_phy=$(ethtool --show-phys "$NSIM_NETDEV" | grep -c "PHY index")
+check $? "$n_phy" "2"
+
+cleanup_netdev_from_id "$NSIM_ID2"
+
+if [ "$num_errors" -eq 0 ]; then
+    echo "PASSED all $((num_passes)) checks"
+    exit 0
+else
+    echo "FAILED $num_errors/$((num_errors+num_passes)) checks"
+    exit 1
+fi
-- 
2.49.0