The free running cycle counter of physical clocks called cycles shall be
used for hardware timestamps to enable synchronisation.

Introduce new flag SKBTX_HW_TSTAMP_USE_CYCLES, which signals driver to
provide a TX timestamp based on cycles if cycles are supported.

Signed-off-by: Gerhard Engleder <redacted>
---
 include/linux/skbuff.h |  5 +++++
 net/core/skbuff.c      |  5 +++++
 net/socket.c           | 11 ++++++++++-
 3 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 3270cb72e4d8..fa03e02b761d 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h

@@ -615,6 +615,11 @@ enum {
 	/* device driver is going to provide hardware time stamp */
 	SKBTX_IN_PROGRESS = 1 << 2,
 
+	/* generate hardware time stamp based on cycles if supported, flag is
+	 * used only for TX path
+	 */
+	SKBTX_HW_TSTAMP_USE_CYCLES = 1 << 3,
+
 	/* generate wifi status information (where possible) */
 	SKBTX_WIFI_STATUS = 1 << 4,