ice: Support HW timestamp hint

Use previously refactored code and create a function
that allows XDP code to read HW timestamp.

Also, introduce packet context, where hints-related data will be stored.
ice_xdp_buff contains only a pointer to this structure, to avoid copying it
in ZC mode later in the series.

HW timestamp is the first supported hint in the driver,
so also add xdp_metadata_ops.

Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: Larysa Zaremba <larysa.zaremba@intel.com>
Link: https://lore.kernel.org/r/20231205210847.28460-6-larysa.zaremba@intel.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

drivers/net/ethernet/intel/ice/ice.h

@@ -996,4 +996,6 @@ static inline void ice_clear_rdma_cap(struct ice_pf *pf)
 	set_bit(ICE_FLAG_UNPLUG_AUX_DEV, pf->flags);
 	clear_bit(ICE_FLAG_RDMA_ENA, pf->flags);
 }
+
+extern const struct xdp_metadata_ops ice_xdp_md_ops;
 #endif /* _ICE_H_ */

drivers/net/ethernet/intel/ice/ice_base.c

@@ -575,6 +575,7 @@ int ice_vsi_cfg_rxq(struct ice_rx_ring *ring)
 
 	xdp_init_buff(&ring->xdp, ice_rx_pg_size(ring) / 2, &ring->xdp_rxq);
 	ring->xdp.data = NULL;
+	ring->xdp_ext.pkt_ctx = &ring->pkt_ctx;
 	err = ice_setup_rx_ctx(ring);
 	if (err) {
 		dev_err(dev, "ice_setup_rx_ctx failed for RxQ %d, err %d\n",

drivers/net/ethernet/intel/ice/ice_main.c

@@ -3397,6 +3397,7 @@ static void ice_set_ops(struct ice_vsi *vsi)
 
 	netdev->netdev_ops = &ice_netdev_ops;
 	netdev->udp_tunnel_nic_info = &pf->hw.udp_tunnel_nic;
+	netdev->xdp_metadata_ops = &ice_xdp_md_ops;
 	ice_set_ethtool_ops(netdev);
 
 	if (vsi->type != ICE_VSI_PF)

drivers/net/ethernet/intel/ice/ice_ptp.c

@@ -2129,12 +2129,12 @@ int ice_ptp_set_ts_config(struct ice_pf *pf, struct ifreq *ifr)
 /**
  * ice_ptp_get_rx_hwts - Get packet Rx timestamp in ns
  * @rx_desc: Receive descriptor
- * @rx_ring: Ring to get the cached time
+ * @pkt_ctx: Packet context to get the cached time
  *
  * The driver receives a notification in the receive descriptor with timestamp.
  */
 u64 ice_ptp_get_rx_hwts(const union ice_32b_rx_flex_desc *rx_desc,
-			struct ice_rx_ring *rx_ring)
+			const struct ice_pkt_ctx *pkt_ctx)
 {
 	u64 ts_ns, cached_time;
 	u32 ts_high;
@@ -2142,7 +2142,7 @@ u64 ice_ptp_get_rx_hwts(const union ice_32b_rx_flex_desc *rx_desc,
 	if (!(rx_desc->wb.time_stamp_low & ICE_PTP_TS_VALID))
 		return 0;
 
-	cached_time = READ_ONCE(rx_ring->cached_phctime);
+	cached_time = READ_ONCE(pkt_ctx->cached_phctime);
 
 	/* Do not report a timestamp if we don't have a cached PHC time */
 	if (!cached_time)

drivers/net/ethernet/intel/ice/ice_ptp.h

@@ -299,7 +299,7 @@ s8 ice_ptp_request_ts(struct ice_ptp_tx *tx, struct sk_buff *skb);
 enum ice_tx_tstamp_work ice_ptp_process_ts(struct ice_pf *pf);
 
 u64 ice_ptp_get_rx_hwts(const union ice_32b_rx_flex_desc *rx_desc,
-			struct ice_rx_ring *rx_ring);
+			const struct ice_pkt_ctx *pkt_ctx);
 void ice_ptp_reset(struct ice_pf *pf);
 void ice_ptp_prepare_for_reset(struct ice_pf *pf);
 void ice_ptp_init(struct ice_pf *pf);
@@ -331,7 +331,7 @@ static inline bool ice_ptp_process_ts(struct ice_pf *pf)
 
 static inline u64
 ice_ptp_get_rx_hwts(const union ice_32b_rx_flex_desc *rx_desc,
-		    struct ice_rx_ring *rx_ring)
+		    const struct ice_pkt_ctx *pkt_ctx)
 {
 	return 0;
 }

drivers/net/ethernet/intel/ice/ice_txrx.h

@@ -257,9 +257,14 @@ enum ice_rx_dtype {
 	ICE_RX_DTYPE_SPLIT_ALWAYS	= 2,
 };
 
+struct ice_pkt_ctx {
+	u64 cached_phctime;
+};
+
 struct ice_xdp_buff {
 	struct xdp_buff xdp_buff;
 	const union ice_32b_rx_flex_desc *eop_desc;
+	const struct ice_pkt_ctx *pkt_ctx;
 };
 
 /* Required for compatibility with xdp_buffs from xsk_pool */
@@ -328,6 +333,10 @@ struct ice_rx_ring {
 		struct xdp_buff xdp;
 	};
 	/* CL3 - 3rd cacheline starts here */
+	union {
+		struct ice_pkt_ctx pkt_ctx;
+		u64 cached_phctime;
+	};
 	struct bpf_prog *xdp_prog;
 	u16 rx_offset;
 
@@ -346,7 +355,6 @@ struct ice_rx_ring {
 	struct ice_rx_ring *next;	/* pointer to next ring in q_vector */
 	struct xsk_buff_pool *xsk_pool;
 	dma_addr_t dma;			/* physical address of ring */
-	u64 cached_phctime;
 	u16 rx_buf_len;
 	u8 dcb_tc;			/* Traffic class of ring */
 	u8 ptp_rx;

drivers/net/ethernet/intel/ice/ice_txrx_lib.c

@@ -197,7 +197,7 @@ ice_ptp_rx_hwts_to_skb(struct ice_rx_ring *rx_ring,
 		       const union ice_32b_rx_flex_desc *rx_desc,
 		       struct sk_buff *skb)
 {
-	u64 ts_ns = ice_ptp_get_rx_hwts(rx_desc, rx_ring);
+	u64 ts_ns = ice_ptp_get_rx_hwts(rx_desc, &rx_ring->pkt_ctx);
 
 	skb_hwtstamps(skb)->hwtstamp = ns_to_ktime(ts_ns);
 }
@@ -507,3 +507,26 @@ void ice_finalize_xdp_rx(struct ice_tx_ring *xdp_ring, unsigned int xdp_res,
 			spin_unlock(&xdp_ring->tx_lock);
 	}
 }
+
+/**
+ * ice_xdp_rx_hw_ts - HW timestamp XDP hint handler
+ * @ctx: XDP buff pointer
+ * @ts_ns: destination address
+ *
+ * Copy HW timestamp (if available) to the destination address.
+ */
+static int ice_xdp_rx_hw_ts(const struct xdp_md *ctx, u64 *ts_ns)
+{
+	const struct ice_xdp_buff *xdp_ext = (void *)ctx;
+
+	*ts_ns = ice_ptp_get_rx_hwts(xdp_ext->eop_desc,
+				     xdp_ext->pkt_ctx);
+	if (!*ts_ns)
+		return -ENODATA;
+
+	return 0;
+}
+
+const struct xdp_metadata_ops ice_xdp_md_ops = {
+	.xmo_rx_timestamp		= ice_xdp_rx_hw_ts,
+};