Add simple tests to validate that the driver sets up timestamping
configuration according to what is reported in capabilities.

For RX timestamping we allow driver to fallback to wider scope for
timestamping if filter is applied. That actually means that driver
can enable ptpv2-event when it reports ptpv2-l4-event is supported,
but not vice versa.

Signed-off-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>
---
 .../selftests/drivers/net/hw/nic_timestamp.py | 75 +++++++++++++++++++
 1 file changed, 75 insertions(+)
 create mode 100755 tools/testing/selftests/drivers/net/hw/nic_timestamp.py

diff --git a/tools/testing/selftests/drivers/net/hw/nic_timestamp.py b/tools/testing/selftests/drivers/net/hw/nic_timestamp.py
new file mode 100755
index 000000000000..758d00c6f965
--- /dev/null
+++ b/tools/testing/selftests/drivers/net/hw/nic_timestamp.py
@@ -0,0 +1,75 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+
+import datetime
+import random
+from lib.py import ksft_run, ksft_exit, ksft_ge, ksft_eq, KsftSkipEx
+from lib.py import NetDrvEnv, EthtoolFamily, NlError
+
+def _getHWTimeStampSupport(cfg):
+    tsinfo = cfg.ethnl.tsinfo_get({'header': {'dev-name': cfg.ifname}})
+    ctx = {}
+    tx = tsinfo.get('tx-types', {})
+    rx = tsinfo.get('rx-filters', {})
+
+    bits = tx.get('bits', {})
+    ctx['tx'] = bits.get('bit', [])
+    bits = rx.get('bits', {})
+    ctx['rx'] = bits.get('bit', [])
+    return ctx
+
+def _getHWTimeStampConfig(cfg):
+    try:
+        tscfg = cfg.ethnl.tsconfig_get({'header': {'dev-name': cfg.ifname}})
+    except NlError as e:
+        if e.error == errno.EOPNOTSUPP:
+            raise KsftSkipEx("timestamping configuration is not supported via netlink") from e
+        raise
+    return tscfg
+
+def _setHWTimeStampConfig(cfg, ts):
+    ts['header'] = {'dev-name': cfg.ifname}
+    try:
+        res = cfg.ethnl.tsconfig_set(ts)
+    except NlError as e:
+	    if e.error == errno.EOPNOTSUPP:
+	        raise KsftSkipEx("timestamping configuration is not supported via netlink") from e
+	    raise
+    return res
+
+def test_hwtstamp_tx(cfg):
+    orig_tscfg = _getHWTimeStampConfig(cfg)
+    ts = _getHWTimeStampSupport(cfg)
+    tx = ts['tx']
+    for t in tx:
+        tscfg = orig_tscfg
+        tscfg['tx-types']['bits']['bit'] = [t]
+        res = _setHWTimeStampConfig(cfg, tscfg)
+        ksft_eq(res['tx-types']['bits']['bit'], [t])
+    _setHWTimeStampConfig(cfg, orig_tscfg)
+
+def test_hwtstamp_rx(cfg):
+    orig_tscfg = _getHWTimeStampConfig(cfg)
+    ts = _getHWTimeStampSupport(cfg)
+    rx = ts['rx']
+    for r in rx:
+        tscfg = orig_tscfg
+        tscfg['rx-filters']['bits']['bit'] = [r]
+        res = _setHWTimeStampConfig(cfg, tscfg)
+        if res is None:
+            res = _getHWTimeStampConfig(cfg)
+        if r['index'] == 0 or r['index'] == 1:
+            ksft_eq(res['rx-filters']['bits']['bit'][0]['index'], r['index'])
+        else:
+            # the driver can fallback to some value which has higher coverage for timestamping
+            ksft_ge(res['rx-filters']['bits']['bit'][0]['index'], r['index'])
+    _setHWTimeStampConfig(cfg, orig_tscfg)
+
+def main() -> None:
+    with NetDrvEnv(__file__, nsim_test=False) as cfg:
+        cfg.ethnl = EthtoolFamily()
+        ksft_run([test_hwtstamp_tx, test_hwtstamp_rx], args=(cfg,))
+        ksft_exit()
+
+if __name__ == "__main__":
+    main()
-- 
2.47.3