On 4/13/2023 8:12 AM, Song Yoong Siang wrote:
igc_configure_rx_ring() function will be called as part of XDP program setup. If Rx hardware timestamp is enabled prio to XDP program setup, this timestamp enablement will be overwritten when buffer size is written into SRRCTL register.
Thus, this commit read the register value before write to SRRCTL register. This commit is tested by using xdp_hw_metadata bpf selftest tool. The tool enables Rx hardware timestamp and then attach XDP program to igc driver. It will display hardware timestamp of UDP packet with port number 9092. Below are detail of test steps and results.
Command on DUT: sudo ./xdp_hw_metadata <interface name>
Command on Link Partner: echo -n skb | nc -u -q1 <destination IPv4 addr> 9092
Result before this patch: skb hwtstamp is not found!
Result after this patch: found skb hwtstamp = 1677762212.590696226
Fixes: fc9df2a0b520 ("igc: Enable RX via AF_XDP zero-copy") Cc: stable@vger.kernel.org # 5.14+ Signed-off-by: Song Yoong Siang yoong.siang.song@intel.com
Reviewed-by: Jacob Keller jacob.e.keller@intel.com