On 13/04/2023 17.12, 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.
Ah, I believe I have hit this bug with my igc patches.
Thanks for fixing.
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>
Why port 9092 ?
The ./xdp_hw_metadata prog will redirect port 9091
Command on Link Partner:
echo -n skb | nc -u -q1 <destination IPv4 addr> 9092
Again port 9092 ?
Result before this patch:
skb hwtstamp is not found!
Result after this patch:
found skb hwtstamp = 1677762212.590696226
I usually use this cmd to see if number is sane:
$ date -d @1677762212
2023-03-02T14:03:32 CET
Fixes: fc9df2a0b520 ("igc: Enable RX via AF_XDP zero-copy")
Cc: <stable@xxxxxxxxxxxxxxx> # 5.14+
Signed-off-by: Song Yoong Siang <yoong.siang.song@xxxxxxxxx>
---
drivers/net/ethernet/intel/igc/igc_base.h | 7 +++++--
drivers/net/ethernet/intel/igc/igc_main.c | 5 ++++-
2 files changed, 9 insertions(+), 3 deletions(-)
diff --git a/drivers/net/ethernet/intel/igc/igc_base.h b/drivers/net/ethernet/intel/igc/igc_base.h
index 7a992befca24..b95007d51d13 100644
--- a/drivers/net/ethernet/intel/igc/igc_base.h
+++ b/drivers/net/ethernet/intel/igc/igc_base.h
@@ -87,8 +87,11 @@ union igc_adv_rx_desc {
#define IGC_RXDCTL_SWFLUSH 0x04000000 /* Receive Software Flush */
/* SRRCTL bit definitions */
-#define IGC_SRRCTL_BSIZEPKT_SHIFT 10 /* Shift _right_ */
-#define IGC_SRRCTL_BSIZEHDRSIZE_SHIFT 2 /* Shift _left_ */
+#define IGC_SRRCTL_BSIZEPKT_MASK GENMASK(6, 0)
+#define IGC_SRRCTL_BSIZEPKT_SHIFT 10 /* Shift _right_ */
+#define IGC_SRRCTL_BSIZEHDRSIZE_MASK GENMASK(13, 8)
+#define IGC_SRRCTL_BSIZEHDRSIZE_SHIFT 2 /* Shift _left_ */
+#define IGC_SRRCTL_DESCTYPE_MASK GENMASK(27, 25)
#define IGC_SRRCTL_DESCTYPE_ADV_ONEBUF 0x02000000
#endif /* _IGC_BASE_H */
diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c
index 25fc6c65209b..de7b21c2ccd6 100644
--- a/drivers/net/ethernet/intel/igc/igc_main.c
+++ b/drivers/net/ethernet/intel/igc/igc_main.c
@@ -641,7 +641,10 @@ static void igc_configure_rx_ring(struct igc_adapter *adapter,
else
buf_size = IGC_RXBUFFER_2048;
- srrctl = IGC_RX_HDR_LEN << IGC_SRRCTL_BSIZEHDRSIZE_SHIFT;
+ srrctl = rd32(IGC_SRRCTL(reg_idx));
+ srrctl &= ~(IGC_SRRCTL_BSIZEPKT_MASK | IGC_SRRCTL_BSIZEHDRSIZE_MASK |
+ IGC_SRRCTL_DESCTYPE_MASK);
+ srrctl |= IGC_RX_HDR_LEN << IGC_SRRCTL_BSIZEHDRSIZE_SHIFT;
srrctl |= buf_size >> IGC_SRRCTL_BSIZEPKT_SHIFT;
srrctl |= IGC_SRRCTL_DESCTYPE_ADV_ONEBUF;
