[PATCH net 2/4] net: ti: icssg: Use undirected TX tag for native XDP in HSR offload mode

[Meghana Malladi]

emac_xmit_xdp_frame() always sets the CPPI5 descriptor destination
tag to emac->port_id, which directs the PRU firmware to transmit
the frame on that specific slave port only.  In HSR offload mode
this bypasses the firmware's HSR duplication logic: the frame goes
out on one ring leg and never appears on the other, breaking HSR
redundancy for XDP_TX paths.

icssg_ndo_start_xmit() already handles this correctly: when HSR
offload mode is active and NETIF_F_HW_HSR_DUP is set it substitutes
PRUETH_UNDIRECTED_PKT_DST_TAG (port 0) so the PRU duplicates the
frame to both slave ports.  It also sets PRUETH_UNDIRECTED_PKT_TAG_INS
in epib[1] when NETIF_F_HW_HSR_TAG_INS is set so the PRU inserts the
HSR sequence tag, which XDP_TX frames lack (the tag is stripped by
the PRU on RX before the frame reaches the XDP program).

Apply the same logic in emac_xmit_xdp_frame() so XDP_TX frames in
HSR mode are treated identically to skb TX via hsr0.

Fixes: 62aa3246f462 ("net: ti: icssg-prueth: Add XDP support")
Signed-off-by: Meghana Malladi <m-malladi at ti.com>
---
 drivers/net/ethernet/ti/icssg/icssg_common.c | 21 ++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/ti/icssg/icssg_common.c b/drivers/net/ethernet/ti/icssg/icssg_common.c
index 55a696912811..ede32f266729 100644
--- a/drivers/net/ethernet/ti/icssg/icssg_common.c
+++ b/drivers/net/ethernet/ti/icssg/icssg_common.c
@@ -696,6 +696,7 @@ u32 emac_xmit_xdp_frame(struct prueth_emac *emac,
 	dma_addr_t desc_dma, buf_dma;
 	struct prueth_swdata *swdata;
 	struct page *page;
+	u32 dst_tag_id;
 	u32 *epib;
 	int ret;
 
@@ -737,9 +738,25 @@ u32 emac_xmit_xdp_frame(struct prueth_emac *emac,
 
 	/* set dst tag to indicate internal qid at the firmware which is at
 	 * bit8..bit15. bit0..bit7 indicates port num for directed
-	 * packets in case of switch mode operation
+	 * packets in case of switch mode operation and port num 0
+	 * for undirected packets in case of HSR offload mode.
+	 *
+	 * XDP_TX frames arrive on a slave port with the HSR tag already
+	 * stripped by the PRU firmware.  Like skb TX via hsr0, they must
+	 * be sent as undirected so the PRU duplicates them to both ports
+	 * and re-inserts the HSR sequence tag.
 	 */
-	cppi5_desc_set_tags_ids(&first_desc->hdr, 0, (emac->port_id | (q_idx << 8)));
+	dst_tag_id = emac->port_id | (q_idx << 8);
+
+	if (emac->prueth->is_hsr_offload_mode &&
+	    (ndev->features & NETIF_F_HW_HSR_DUP))
+		dst_tag_id = PRUETH_UNDIRECTED_PKT_DST_TAG;
+
+	if (emac->prueth->is_hsr_offload_mode &&
+	    (ndev->features & NETIF_F_HW_HSR_TAG_INS))
+		epib[1] |= PRUETH_UNDIRECTED_PKT_TAG_INS;
+
+	cppi5_desc_set_tags_ids(&first_desc->hdr, 0, dst_tag_id);
 	k3_udma_glue_tx_dma_to_cppi5_addr(tx_chn->tx_chn, &buf_dma);
 	cppi5_hdesc_attach_buf(first_desc, buf_dma, xdpf->len, buf_dma, xdpf->len);
 	swdata = cppi5_hdesc_get_swdata(first_desc);
-- 
2.43.0