net: ti: icssg-prueth: Add XDP support

Add native XDP support. We do not support zero copy yet.

Signed-off-by: Roger Quadros <rogerq@kernel.org>
Signed-off-by: MD Danish Anwar <danishanwar@ti.com>
Signed-off-by: Meghana Malladi <m-malladi@ti.com>
Link: https://patch.msgid.link/20250305101422.1908370-4-m-malladi@ti.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Author: rogerq

drivers/net/ethernet/ti/icssg/icssg_common.c

@@ -98,11 +98,20 @@ void prueth_xmit_free(struct prueth_tx_chn *tx_chn,
 {
 	struct cppi5_host_desc_t *first_desc, *next_desc;
 	dma_addr_t buf_dma, next_desc_dma;
+	struct prueth_swdata *swdata;
+	struct page *page;
 	u32 buf_dma_len;
 
 	first_desc = desc;
 	next_desc = first_desc;
 
+	swdata = cppi5_hdesc_get_swdata(desc);
+	if (swdata->type == PRUETH_SWDATA_PAGE) {
+		page = swdata->data.page;
+		page_pool_recycle_direct(page->pp, swdata->data.page);
+		goto free_desc;
+	}
+
 	cppi5_hdesc_get_obuf(first_desc, &buf_dma, &buf_dma_len);
 	k3_udma_glue_tx_cppi5_to_dma_addr(tx_chn->tx_chn, &buf_dma);
 
@@ -126,6 +135,7 @@ void prueth_xmit_free(struct prueth_tx_chn *tx_chn,
 		k3_cppi_desc_pool_free(tx_chn->desc_pool, next_desc);
 	}
 
+free_desc:
 	k3_cppi_desc_pool_free(tx_chn->desc_pool, first_desc);
 }
 EXPORT_SYMBOL_GPL(prueth_xmit_free);
@@ -139,6 +149,7 @@ int emac_tx_complete_packets(struct prueth_emac *emac, int chn,
 	struct prueth_swdata *swdata;
 	struct prueth_tx_chn *tx_chn;
 	unsigned int total_bytes = 0;
+	struct xdp_frame *xdpf;
 	struct sk_buff *skb;
 	dma_addr_t desc_dma;
 	int res, num_tx = 0;
@@ -161,16 +172,28 @@ int emac_tx_complete_packets(struct prueth_emac *emac, int chn,
 		desc_tx = k3_cppi_desc_pool_dma2virt(tx_chn->desc_pool,
 						     desc_dma);
 		swdata = cppi5_hdesc_get_swdata(desc_tx);
-		prueth_xmit_free(tx_chn, desc_tx);
-		if (swdata->type != PRUETH_SWDATA_SKB)
+
+		switch (swdata->type) {
+		case PRUETH_SWDATA_SKB:
+			skb = swdata->data.skb;
+			dev_sw_netstats_tx_add(skb->dev, 1, skb->len);
+			total_bytes += skb->len;
+			napi_consume_skb(skb, budget);
+			break;
+		case PRUETH_SWDATA_XDPF:
+			xdpf = swdata->data.xdpf;
+			dev_sw_netstats_tx_add(ndev, 1, xdpf->len);
+			total_bytes += xdpf->len;
+			xdp_return_frame(xdpf);
+			break;
+		default:
+			netdev_err(ndev, "tx_complete: invalid swdata type %d\n", swdata->type);
+			prueth_xmit_free(tx_chn, desc_tx);
+			ndev->stats.tx_dropped++;
 			continue;
+		}
 
-		skb = swdata->data.skb;
-		ndev = skb->dev;
-		ndev->stats.tx_packets++;
-		ndev->stats.tx_bytes += skb->len;
-		total_bytes += skb->len;
-		napi_consume_skb(skb, budget);
+		prueth_xmit_free(tx_chn, desc_tx);
 		num_tx++;
 	}
 
@@ -529,7 +552,153 @@ void emac_rx_timestamp(struct prueth_emac *emac,
 	ssh->hwtstamp = ns_to_ktime(ns);
 }
 
-static int emac_rx_packet(struct prueth_emac *emac, u32 flow_id)
+/**
+ * emac_xmit_xdp_frame - transmits an XDP frame
+ * @emac: emac device
+ * @xdpf: data to transmit
+ * @page: page from page pool if already DMA mapped
+ * @q_idx: queue id
+ *
+ * Return: XDP state
+ */
+u32 emac_xmit_xdp_frame(struct prueth_emac *emac,
+			struct xdp_frame *xdpf,
+			struct page *page,
+			unsigned int q_idx)
+{
+	struct cppi5_host_desc_t *first_desc;
+	struct net_device *ndev = emac->ndev;
+	struct prueth_tx_chn *tx_chn;
+	dma_addr_t desc_dma, buf_dma;
+	struct prueth_swdata *swdata;
+	u32 *epib;
+	int ret;
+
+	if (q_idx >= PRUETH_MAX_TX_QUEUES) {
+		netdev_err(ndev, "xdp tx: invalid q_id %d\n", q_idx);
+		return ICSSG_XDP_CONSUMED;	/* drop */
+	}
+
+	tx_chn = &emac->tx_chns[q_idx];
+
+	first_desc = k3_cppi_desc_pool_alloc(tx_chn->desc_pool);
+	if (!first_desc) {
+		netdev_dbg(ndev, "xdp tx: failed to allocate descriptor\n");
+		goto drop_free_descs;	/* drop */
+	}
+
+	if (page) { /* already DMA mapped by page_pool */
+		buf_dma = page_pool_get_dma_addr(page);
+		buf_dma += xdpf->headroom + sizeof(struct xdp_frame);
+	} else { /* Map the linear buffer */
+		buf_dma = dma_map_single(tx_chn->dma_dev, xdpf->data, xdpf->len, DMA_TO_DEVICE);
+		if (dma_mapping_error(tx_chn->dma_dev, buf_dma)) {
+			netdev_err(ndev, "xdp tx: failed to map data buffer\n");
+			goto drop_free_descs;	/* drop */
+		}
+	}
+
+	cppi5_hdesc_init(first_desc, CPPI5_INFO0_HDESC_EPIB_PRESENT,
+			 PRUETH_NAV_PS_DATA_SIZE);
+	cppi5_hdesc_set_pkttype(first_desc, 0);
+	epib = first_desc->epib;
+	epib[0] = 0;
+	epib[1] = 0;
+
+	/* 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
+	 */
+	cppi5_desc_set_tags_ids(&first_desc->hdr, 0, (emac->port_id | (q_idx << 8)));
+	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);
+	if (page) {
+		swdata->type = PRUETH_SWDATA_PAGE;
+		swdata->data.page = page;
+	} else {
+		swdata->type = PRUETH_SWDATA_XDPF;
+		swdata->data.xdpf = xdpf;
+	}
+
+	cppi5_hdesc_set_pktlen(first_desc, xdpf->len);
+	desc_dma = k3_cppi_desc_pool_virt2dma(tx_chn->desc_pool, first_desc);
+
+	ret = k3_udma_glue_push_tx_chn(tx_chn->tx_chn, first_desc, desc_dma);
+	if (ret) {
+		netdev_err(ndev, "xdp tx: push failed: %d\n", ret);
+		goto drop_free_descs;
+	}
+
+	return ICSSG_XDP_TX;
+
+drop_free_descs:
+	prueth_xmit_free(tx_chn, first_desc);
+	return ICSSG_XDP_CONSUMED;
+}
+EXPORT_SYMBOL_GPL(emac_xmit_xdp_frame);
+
+/**
+ * emac_run_xdp - run an XDP program
+ * @emac: emac device
+ * @xdp: XDP buffer containing the frame
+ * @page: page with RX data if already DMA mapped
+ * @len: Rx descriptor packet length
+ *
+ * Return: XDP state
+ */
+static u32 emac_run_xdp(struct prueth_emac *emac, struct xdp_buff *xdp,
+			struct page *page, u32 *len)
+{
+	struct net_device *ndev = emac->ndev;
+	struct bpf_prog *xdp_prog;
+	struct xdp_frame *xdpf;
+	u32 pkt_len = *len;
+	u32 act, result;
+	int q_idx, err;
+
+	xdp_prog = READ_ONCE(emac->xdp_prog);
+	act = bpf_prog_run_xdp(xdp_prog, xdp);
+	switch (act) {
+	case XDP_PASS:
+		return ICSSG_XDP_PASS;
+	case XDP_TX:
+		/* Send packet to TX ring for immediate transmission */
+		xdpf = xdp_convert_buff_to_frame(xdp);
+		if (unlikely(!xdpf)) {
+			ndev->stats.tx_dropped++;
+			goto drop;
+		}
+
+		q_idx = smp_processor_id() % emac->tx_ch_num;
+		result = emac_xmit_xdp_frame(emac, xdpf, page, q_idx);
+		if (result == ICSSG_XDP_CONSUMED)
+			goto drop;
+
+		dev_sw_netstats_rx_add(ndev, xdpf->len);
+		return result;
+	case XDP_REDIRECT:
+		err = xdp_do_redirect(emac->ndev, xdp, xdp_prog);
+		if (err)
+			goto drop;
+
+		dev_sw_netstats_rx_add(ndev, pkt_len);
+		return ICSSG_XDP_REDIR;
+	default:
+		bpf_warn_invalid_xdp_action(emac->ndev, xdp_prog, act);
+		fallthrough;
+	case XDP_ABORTED:
+drop:
+		trace_xdp_exception(emac->ndev, xdp_prog, act);
+		fallthrough; /* handle aborts by dropping packet */
+	case XDP_DROP:
+		ndev->stats.rx_dropped++;
+		page_pool_recycle_direct(emac->rx_chns.pg_pool, page);
+		return ICSSG_XDP_CONSUMED;
+	}
+}
+
+static int emac_rx_packet(struct prueth_emac *emac, u32 flow_id, u32 *xdp_state)
 {
 	struct prueth_rx_chn *rx_chn = &emac->rx_chns;
 	u32 buf_dma_len, pkt_len, port_id = 0;
@@ -540,10 +709,12 @@ static int emac_rx_packet(struct prueth_emac *emac, u32 flow_id)
 	struct page *page, *new_page;
 	struct page_pool *pool;
 	struct sk_buff *skb;
+	struct xdp_buff xdp;
 	u32 *psdata;
 	void *pa;
 	int ret;
 
+	*xdp_state = 0;
 	pool = rx_chn->pg_pool;
 	ret = k3_udma_glue_pop_rx_chn(rx_chn->rx_chn, flow_id, &desc_dma);
 	if (ret) {
@@ -584,9 +755,21 @@ static int emac_rx_packet(struct prueth_emac *emac, u32 flow_id)
 		goto requeue;
 	}
 
-	/* prepare skb and send to n/w stack */
 	pa = page_address(page);
-	skb = napi_build_skb(pa, PAGE_SIZE);
+	if (emac->xdp_prog) {
+		xdp_init_buff(&xdp, PAGE_SIZE, &rx_chn->xdp_rxq);
+		xdp_prepare_buff(&xdp, pa, PRUETH_HEADROOM, pkt_len, false);
+
+		*xdp_state = emac_run_xdp(emac, &xdp, page, &pkt_len);
+		if (*xdp_state == ICSSG_XDP_PASS)
+			skb = xdp_build_skb_from_buff(&xdp);
+		else
+			goto requeue;
+	} else {
+		/* prepare skb and send to n/w stack */
+		skb = napi_build_skb(pa, PAGE_SIZE);
+	}
+
 	if (!skb) {
 		ndev->stats.rx_dropped++;
 		page_pool_recycle_direct(pool, page);
@@ -849,13 +1032,23 @@ static void prueth_tx_cleanup(void *data, dma_addr_t desc_dma)
 	struct prueth_tx_chn *tx_chn = data;
 	struct cppi5_host_desc_t *desc_tx;
 	struct prueth_swdata *swdata;
+	struct xdp_frame *xdpf;
 	struct sk_buff *skb;
 
 	desc_tx = k3_cppi_desc_pool_dma2virt(tx_chn->desc_pool, desc_dma);
 	swdata = cppi5_hdesc_get_swdata(desc_tx);
-	if (swdata->type == PRUETH_SWDATA_SKB) {
+
+	switch (swdata->type) {
+	case PRUETH_SWDATA_SKB:
 		skb = swdata->data.skb;
 		dev_kfree_skb_any(skb);
+		break;
+	case PRUETH_SWDATA_XDPF:
+		xdpf = swdata->data.xdpf;
+		xdp_return_frame(xdpf);
+		break;
+	default:
+		break;
 	}
 
 	prueth_xmit_free(tx_chn, desc_tx);
@@ -892,15 +1085,18 @@ int icssg_napi_rx_poll(struct napi_struct *napi_rx, int budget)
 		PRUETH_RX_FLOW_DATA_SR1 : PRUETH_RX_FLOW_DATA;
 	int flow = emac->is_sr1 ?
 		PRUETH_MAX_RX_FLOWS_SR1 : PRUETH_MAX_RX_FLOWS;
+	int xdp_state_or = 0;
 	int num_rx = 0;
 	int cur_budget;
+	u32 xdp_state;
 	int ret;
 
 	while (flow--) {
 		cur_budget = budget - num_rx;
 
 		while (cur_budget--) {
-			ret = emac_rx_packet(emac, flow);
+			ret = emac_rx_packet(emac, flow, &xdp_state);
+			xdp_state_or |= xdp_state;
 			if (ret)
 				break;
 			num_rx++;
@@ -910,6 +1106,9 @@ int icssg_napi_rx_poll(struct napi_struct *napi_rx, int budget)
 			break;
 	}
 
+	if (xdp_state_or & ICSSG_XDP_REDIR)
+		xdp_do_flush();
+
 	if (num_rx < budget && napi_complete_done(napi_rx, num_rx)) {
 		if (unlikely(emac->rx_pace_timeout_ns)) {
 			hrtimer_start(&emac->rx_hrtimer,