Dell Mellanox Family of Adapters - Manual (Page 34)

Driver Installation and Configuration Rev 1.1
Mellanox Technologies 34
 To enable time stamping for a net device:
Admin privileged user can enable/disable time stamping through calling ioctl(sock, SIOCSHWT-
STAMP, &ifreq) with following values:
Send side time sampling:
• Enabled by ifreq.hwtstamp_config.tx_type when
/* possible values for hwtstamp_config->tx_type */
enum hwtstamp_tx_types {
/*
* No outgoing packet will need hardware time stamping;
* should a packet arrive which asks for it, no hardware
* time stamping will be done.
*/
HWTSTAMP_TX_OFF,
/*
* Enables hardware time stamping for outgoing packets;
* the sender of the packet decides which are to be
* time stamped by setting %SOF_TIMESTAMPING_TX_SOFTWARE
* before sending the packet.
*/
HWTSTAMP_TX_ON,
/*
* Enables time stamping for outgoing packets just as
* HWTSTAMP_TX_ON does, but also enables time stamp insertion
* directly into Sync packets. In this case, transmitted Sync
* packets will not received a time stamp via the socket error
* queue.
*/
HWTSTAMP_TX_ONESTEP_SYNC,
};
Note: for send side time stamping currently only HWTSTAMP_TX_OFF and
HWTSTAMP_TX_ON are supported.