igb: use timecompare to implement hardware time stamping

Both TX and RX hardware time stamping are implemented.  Due to
hardware limitations it is not possible to verify reliably which
packet was time stamped when multiple were pending for sending; this
could be solved by only allowing one packet marked for hardware time
stamping into the queue (not implemented yet).

RX time stamping relies on the flag in the packet descriptor which
marks packets that were time stamped. In "all packet" mode this flag
is not set. TODO: also support that mode (even though it'll suffer
from race conditions).

Signed-off-by: John Ronciak <john.ronciak@intel.com>
Signed-off-by: Patrick Ohly <patrick.ohly@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/net/igb/e1000_82575.h b/drivers/net/igb/e1000_82575.h
index dd50237c8cb0..e613d5a606d8 100644
--- a/drivers/net/igb/e1000_82575.h
+++ b/drivers/net/igb/e1000_82575.h
@@ -116,6 +116,7 @@ union e1000_adv_tx_desc {
 };
 
 /* Adv Transmit Descriptor Config Masks */
+#define E1000_ADVTXD_MAC_TSTAMP   0x00080000 /* IEEE1588 Timestamp packet */
 #define E1000_ADVTXD_DTYP_CTXT    0x00200000 /* Advanced Context Descriptor */
 #define E1000_ADVTXD_DTYP_DATA    0x00300000 /* Advanced Data Descriptor */
 #define E1000_ADVTXD_DCMD_IFCS    0x02000000 /* Insert FCS (Ethernet CRC) */