[PATCH iwl-next v4] idpf: export RX hardware timestamping information to XDP

[Mina Almasry <almasrymina@google.com>]

From: YiFei Zhu <zhuyifei@google.com>

The logic is similar to idpf_rx_hwtstamp, but the data is exported
as a BPF kfunc instead of appended to an skb to support grabbing
timestamps in xsk packets.

A idpf_queue_has(PTP, rxq) condition is added to check the queue
supports PTP similar to idpf_rx_process_skb_fields.

Tested using an xsk connection and checking xdp timestamps are
retreivable in received packets.

Cc: intel-wired-lan@lists.osuosl.org
Signed-off-by: YiFei Zhu <zhuyifei@google.com>
Signed-off-by: Mina Almasry <almasrymina@google.com>
Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>

---

v4: https://lore.kernel.org/netdev/20251219202957.2309698-1-almasrymina@google.com/
- Fix indentation (lobakin)
- I kept the (u64) casts for all bit shifted bits in idpf_xdp_get_qw3
  and friends as I see all idpf_xdp_get_qw* functions do the cast in all
  bit-shifted variables.

v3: https://lore.kernel.org/netdev/20251218022948.3288897-1-almasrymina@google.com/
- Do the idpf_queue_has(PTP) check before we read qw1 (lobakin)
- Fix _qw1 not copying over ts_low on on !__LIBETH_WORD_ACCESS systems
  (AI)

v2: https://lore.kernel.org/netdev/20251122140839.3922015-1-almasrymina@google.com/
- Fixed alphabetical ordering
- Use the xdp desc type instead of virtchnl one (required some added
  helpers)

---
 drivers/net/ethernet/intel/idpf/xdp.c | 31 +++++++++++++++++++++++++++
 drivers/net/ethernet/intel/idpf/xdp.h | 20 +++++++++++++++++
 2 files changed, 51 insertions(+)

diff --git a/drivers/net/ethernet/intel/idpf/xdp.c b/drivers/net/ethernet/intel/idpf/xdp.c
index 958d16f87424..0916d201bf98 100644
--- a/drivers/net/ethernet/intel/idpf/xdp.c
+++ b/drivers/net/ethernet/intel/idpf/xdp.c
@@ -2,6 +2,7 @@
 /* Copyright (C) 2025 Intel Corporation */
 
 #include "idpf.h"
+#include "idpf_ptp.h"
 #include "idpf_virtchnl.h"
 #include "xdp.h"
 #include "xsk.h"
@@ -391,8 +392,38 @@ static int idpf_xdpmo_rx_hash(const struct xdp_md *ctx, u32 *hash,
 				    pt);
 }
 
+static int idpf_xdpmo_rx_timestamp(const struct xdp_md *ctx, u64 *timestamp)
+{
+	const struct libeth_xdp_buff *xdp = (typeof(xdp))ctx;
+	struct idpf_xdp_rx_desc desc __uninitialized;
+	const struct idpf_rx_queue *rxq;
+	u64 cached_time, ts_ns;
+	u32 ts_high;
+
+	rxq = libeth_xdp_buff_to_rq(xdp, typeof(*rxq), xdp_rxq);
+
+	if (!idpf_queue_has(PTP, rxq))
+		return -ENODATA;
+
+	idpf_xdp_get_qw1(&desc, xdp->desc);
+
+	if (!(idpf_xdp_rx_ts_low(&desc) & VIRTCHNL2_RX_FLEX_TSTAMP_VALID))
+		return -ENODATA;
+
+	cached_time = READ_ONCE(rxq->cached_phc_time);
+
+	idpf_xdp_get_qw3(&desc, xdp->desc);
+
+	ts_high = idpf_xdp_rx_ts_high(&desc);
+	ts_ns = idpf_ptp_tstamp_extend_32b_to_64b(cached_time, ts_high);
+
+	*timestamp = ts_ns;
+	return 0;
+}
+
 static const struct xdp_metadata_ops idpf_xdpmo = {
 	.xmo_rx_hash		= idpf_xdpmo_rx_hash,
+	.xmo_rx_timestamp	= idpf_xdpmo_rx_timestamp,
 };
 
 void idpf_xdp_set_features(const struct idpf_vport *vport)
diff --git a/drivers/net/ethernet/intel/idpf/xdp.h b/drivers/net/ethernet/intel/idpf/xdp.h
index 479f5ef3c604..1748a0d73547 100644
--- a/drivers/net/ethernet/intel/idpf/xdp.h
+++ b/drivers/net/ethernet/intel/idpf/xdp.h
@@ -112,11 +112,13 @@ struct idpf_xdp_rx_desc {
 	aligned_u64		qw1;
 #define IDPF_XDP_RX_BUF		GENMASK_ULL(47, 32)
 #define IDPF_XDP_RX_EOP		BIT_ULL(1)
+#define IDPF_XDP_RX_TS_LOW	GENMASK_ULL(31, 24)
 
 	aligned_u64		qw2;
 #define IDPF_XDP_RX_HASH	GENMASK_ULL(31, 0)
 
 	aligned_u64		qw3;
+#define IDPF_XDP_RX_TS_HIGH	GENMASK_ULL(63, 32)
 } __aligned(4 * sizeof(u64));
 static_assert(sizeof(struct idpf_xdp_rx_desc) ==
 	      sizeof(struct virtchnl2_rx_flex_desc_adv_nic_3));
@@ -128,6 +130,8 @@ static_assert(sizeof(struct idpf_xdp_rx_desc) ==
 #define idpf_xdp_rx_buf(desc)	FIELD_GET(IDPF_XDP_RX_BUF, (desc)->qw1)
 #define idpf_xdp_rx_eop(desc)	!!((desc)->qw1 & IDPF_XDP_RX_EOP)
 #define idpf_xdp_rx_hash(desc)	FIELD_GET(IDPF_XDP_RX_HASH, (desc)->qw2)
+#define idpf_xdp_rx_ts_low(desc)	FIELD_GET(IDPF_XDP_RX_TS_LOW, (desc)->qw1)
+#define idpf_xdp_rx_ts_high(desc)	FIELD_GET(IDPF_XDP_RX_TS_HIGH, (desc)->qw3)
 
 static inline void
 idpf_xdp_get_qw0(struct idpf_xdp_rx_desc *desc,
@@ -149,6 +153,9 @@ idpf_xdp_get_qw1(struct idpf_xdp_rx_desc *desc,
 	desc->qw1 = ((const typeof(desc))rxd)->qw1;
 #else
 	desc->qw1 = ((u64)le16_to_cpu(rxd->buf_id) << 32) |
+		    ((u64)rxd->ts_low << 24) |
+		    ((u64)rxd->fflags1 << 16) |
+		    ((u64)rxd->status_err1 << 8) |
 		    rxd->status_err0_qw1;
 #endif
 }
@@ -166,6 +173,19 @@ idpf_xdp_get_qw2(struct idpf_xdp_rx_desc *desc,
 #endif
 }
 
+static inline void
+idpf_xdp_get_qw3(struct idpf_xdp_rx_desc *desc,
+		 const struct virtchnl2_rx_flex_desc_adv_nic_3 *rxd)
+{
+#ifdef __LIBETH_WORD_ACCESS
+	desc->qw3 = ((const typeof(desc))rxd)->qw3;
+#else
+	desc->qw3 = ((u64)le32_to_cpu(rxd->ts_high) << 32) |
+		    ((u64)le16_to_cpu(rxd->fmd6) << 16) |
+		    le16_to_cpu(rxd->l2tag1);
+#endif
+}
+
 void idpf_xdp_set_features(const struct idpf_vport *vport);
 
 int idpf_xdp(struct net_device *dev, struct netdev_bpf *xdp);

base-commit: 7b8e9264f55a9c320f398e337d215e68cca50131
-- 
2.52.0.351.gbe84eed79e-goog