sfc: PTP changes to support improved UUID filtering mode

There is a long-standing problem with the packet-timestamp matching in
the driver. When a PTP packet is received by the MC, the FPGA
timestamps the packet and the MC sends the timestamp and 6 bytes of
the UUID to the driver. The driver then matches the timestamp against
received packets using the same 6 bytes of UUID.

The problem comes from the choice of which 6 bytes to use. The PTP
spec is slightly contradictory and misleading in one of the two places
where the UUIDs are discussed. From section 7.2.2.2 of the spec, a
PTPD2 UUID can be either a EUI-64 or a EUI-64 constructed from a
EUI-48. The typical ethernet based implementation uses a EUI-64
constructed from a EUI-48. This works by taking the first 3 bytes of
the MAC address of the NIC being used for PTP (the OUI), then
inserting 0xFF, 0xFE, then taking the last 3 bytes of the MAC address
giving
          MAC[0], MAC[1], MAC[2], 0xFF, 0xFE, MAC[3], MAC[4], MAC[5]
The current MC firmware and driver discard the first two bytes of this
UUID and packets are matched against timestamps using bytes 2 to 7 so
there is a small risk that in a deployment of Solarflare PTP NICs used
with other vendors NICs, that a PTP packet could be matched against
the wrong timestamp. This applies to all other organisations whose
third byte of the OUI is 0x53. It's a long list but I notice that it
includes Cisco.

The necessary modifications to use bytes 0-2 and 5-7 of the UUID to
match against are quite small but introduce incompatibility between
older version of the firmware and driver.

When PTP is enabled via SO_TIMESTAMPING specifying PTP V2, the driver
will try to enable PTP in the firmware using the enhanced mode
(above). If the firmware returns an error, the driver will enable PTP
in the firmware using the old mode.

[bwh: Fix some style errors; remove private ioctl bits]
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/net/ethernet/sfc/mcdi_pcol.h b/drivers/net/ethernet/sfc/mcdi_pcol.h
index 9d426d0457bd..c5c9747861ba 100644
--- a/drivers/net/ethernet/sfc/mcdi_pcol.h
+++ b/drivers/net/ethernet/sfc/mcdi_pcol.h
@@ -553,6 +553,7 @@
 #define          MC_CMD_PTP_MODE_V1_VLAN 0x1 /* enum */
 #define          MC_CMD_PTP_MODE_V2 0x2 /* enum */
 #define          MC_CMD_PTP_MODE_V2_VLAN 0x3 /* enum */
+#define          MC_CMD_PTP_MODE_V2_ENHANCED 0x4 /* enum */
 
 /* MC_CMD_PTP_IN_DISABLE msgrequest */
 #define    MC_CMD_PTP_IN_DISABLE_LEN 8