[PATCH v2 0/2] Add minimal XDP support to TI AM65 CPSW Ethernet driver

[PATCH v2 0/2] Add minimal XDP support to TI AM65 CPSW Ethernet driver

[Julien Panis]

This patch adds XDP support to TI AM65 CPSW Ethernet driver.

The following features are implemented: NETDEV_XDP_ACT_BASIC,
NETDEV_XDP_ACT_REDIRECT, and NETDEV_XDP_ACT_NDO_XMIT.

Zero-copy and non-linear XDP buffer supports are NOT implemented.

Besides, the page pool memory model is used to get better performance.

Signed-off-by: Julien Panis <jpanis@baylibre.com>
---
Changes in v2:
- Use page pool memory model instead of MEM_TYPE_PAGE_ORDER0.
- In am65_cpsw_alloc_skb(), release reference on the page pool page
in case of error returned by build_skb().
- [nit] Cleanup am65_cpsw_nuss_common_open/stop() functions.
- [nit] Arrange local variables in reverse xmas tree order.
- Link to v1: https://lore.kernel.org/r/20240223-am65-cpsw-xdp-basic-v1-1-9f0b6cbda310@baylibre.com

---
Julien Panis (2):
      net: ethernet: ti: Add accessors for struct k3_cppi_desc_pool members
      net: ethernet: ti: am65-cpsw: Add minimal XDP support

 drivers/net/ethernet/ti/am65-cpsw-nuss.c    | 490 +++++++++++++++++++++++++---
 drivers/net/ethernet/ti/am65-cpsw-nuss.h    |  13 +
 drivers/net/ethernet/ti/k3-cppi-desc-pool.c |  12 +
 drivers/net/ethernet/ti/k3-cppi-desc-pool.h |   2 +
 4 files changed, 469 insertions(+), 48 deletions(-)
---
base-commit: 6613476e225e090cc9aad49be7fa504e290dd33d
change-id: 20240223-am65-cpsw-xdp-basic-4db828508b48

Best regards,
-- 
Julien Panis <jpanis@baylibre.com>

[PATCH v2 1/2] net: ethernet: ti: Add accessors for struct k3_cppi_desc_pool members

[Julien Panis]

This patch adds accessors for desc_size and cpumem members. They may be
necessary, for instance, to compute a page pool page index.

Signed-off-by: Julien Panis <jpanis@baylibre.com>
---
 drivers/net/ethernet/ti/k3-cppi-desc-pool.c | 12 ++++++++++++
 drivers/net/ethernet/ti/k3-cppi-desc-pool.h |  2 ++
 2 files changed, 14 insertions(+)

diff --git a/drivers/net/ethernet/ti/k3-cppi-desc-pool.c b/drivers/net/ethernet/ti/k3-cppi-desc-pool.c
index 05cc7aab1ec8..fe8203c05731 100644
--- a/drivers/net/ethernet/ti/k3-cppi-desc-pool.c
+++ b/drivers/net/ethernet/ti/k3-cppi-desc-pool.c
@@ -132,5 +132,17 @@ size_t k3_cppi_desc_pool_avail(struct k3_cppi_desc_pool *pool)
 }
 EXPORT_SYMBOL_GPL(k3_cppi_desc_pool_avail);
 
+size_t k3_cppi_desc_pool_desc_size(struct k3_cppi_desc_pool *pool)
+{
+	return pool->desc_size;
+}
+EXPORT_SYMBOL_GPL(k3_cppi_desc_pool_desc_size);
+
+void *k3_cppi_desc_pool_cpuaddr(struct k3_cppi_desc_pool *pool)
+{
+	return pool->cpumem;
+}
+EXPORT_SYMBOL_GPL(k3_cppi_desc_pool_cpuaddr);
+
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("TI K3 CPPI5 descriptors pool API");
diff --git a/drivers/net/ethernet/ti/k3-cppi-desc-pool.h b/drivers/net/ethernet/ti/k3-cppi-desc-pool.h
index a7e3fa5e7b62..149d5579a5e2 100644
--- a/drivers/net/ethernet/ti/k3-cppi-desc-pool.h
+++ b/drivers/net/ethernet/ti/k3-cppi-desc-pool.h
@@ -26,5 +26,7 @@ k3_cppi_desc_pool_dma2virt(struct k3_cppi_desc_pool *pool, dma_addr_t dma);
 void *k3_cppi_desc_pool_alloc(struct k3_cppi_desc_pool *pool);
 void k3_cppi_desc_pool_free(struct k3_cppi_desc_pool *pool, void *addr);
 size_t k3_cppi_desc_pool_avail(struct k3_cppi_desc_pool *pool);
+size_t k3_cppi_desc_pool_desc_size(struct k3_cppi_desc_pool *pool);
+void *k3_cppi_desc_pool_cpuaddr(struct k3_cppi_desc_pool *pool);
 
 #endif /* K3_CPPI_DESC_POOL_H_ */

-- 
2.37.3

[PATCH v2 2/2] net: ethernet: ti: am65-cpsw: Add minimal XDP support

[Julien Panis]

This patch adds XDP (eXpress Data Path) support to TI AM65 CPSW
Ethernet driver. The following features are implemented:
- NETDEV_XDP_ACT_BASIC (XDP_PASS, XDP_TX, XDP_DROP, XDP_ABORTED)
- NETDEV_XDP_ACT_REDIRECT (XDP_REDIRECT)
- NETDEV_XDP_ACT_NDO_XMIT (ndo_xdp_xmit callback)

The page pool memory model is used to get better performance.

Signed-off-by: Julien Panis <jpanis@baylibre.com>
---
 drivers/net/ethernet/ti/am65-cpsw-nuss.c | 490 ++++++++++++++++++++++++++++---
 drivers/net/ethernet/ti/am65-cpsw-nuss.h |  13 +
 2 files changed, 455 insertions(+), 48 deletions(-)

diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
index 9d2f4ac783e4..d6ee3ac07e52 100644
--- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
+++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
@@ -5,6 +5,7 @@
  *
  */
 
+#include <linux/bpf_trace.h>
 #include <linux/clk.h>
 #include <linux/etherdevice.h>
 #include <linux/if_vlan.h>
@@ -30,6 +31,7 @@
 #include <linux/sys_soc.h>
 #include <linux/dma/ti-cppi5.h>
 #include <linux/dma/k3-udma-glue.h>
+#include <net/page_pool/helpers.h>
 #include <net/switchdev.h>
 
 #include "cpsw_ale.h"
@@ -138,6 +140,17 @@
 
 #define AM65_CPSW_DEFAULT_TX_CHNS	8
 
+/* CPPI streaming packet interface */
+#define AM65_CPSW_CPPI_TX_FLOW_ID  0x3FFF
+#define AM65_CPSW_CPPI_TX_PKT_TYPE 0x7
+
+/* XDP */
+#define AM65_CPSW_XDP_CONSUMED	1
+#define AM65_CPSW_XDP_PASS	0
+
+/* Include headroom compatible with both skb and xdpf */
+#define AM65_CPSW_HEADROOM max(NET_SKB_PAD, XDP_PACKET_HEADROOM)
+
 static void am65_cpsw_port_set_sl_mac(struct am65_cpsw_port *slave,
 				      const u8 *dev_addr)
 {
@@ -369,6 +382,65 @@ static void am65_cpsw_init_host_port_emac(struct am65_cpsw_common *common);
 static void am65_cpsw_init_port_switch_ale(struct am65_cpsw_port *port);
 static void am65_cpsw_init_port_emac_ale(struct am65_cpsw_port *port);
 
+static void am65_cpsw_destroy_xdp_rxqs(struct am65_cpsw_common *common)
+{
+	struct am65_cpsw_rx_chn *rx_chn = &common->rx_chns;
+	struct xdp_rxq_info *rxq;
+	int i;
+
+	for (i = 0; i < common->port_num; i++) {
+		rxq = &common->ports[i].xdp_rxq;
+
+		if (xdp_rxq_info_is_reg(rxq))
+			xdp_rxq_info_unreg(rxq);
+	}
+
+	if (rx_chn->page_pool) {
+		page_pool_destroy(rx_chn->page_pool);
+		rx_chn->page_pool = NULL;
+	}
+}
+
+static int am65_cpsw_create_xdp_rxqs(struct am65_cpsw_common *common)
+{
+	struct am65_cpsw_rx_chn *rx_chn = &common->rx_chns;
+	struct page_pool_params pp_params = {
+		.flags = PP_FLAG_DMA_MAP,
+		.order = 0,
+		.pool_size = AM65_CPSW_MAX_RX_DESC,
+		.nid = dev_to_node(common->dev),
+		.dev = common->dev,
+		.dma_dir = DMA_BIDIRECTIONAL,
+	};
+	struct xdp_rxq_info *rxq;
+	struct page_pool *pool;
+	int i, ret;
+
+	pool = page_pool_create(&pp_params);
+	if (IS_ERR(pool))
+		return PTR_ERR(pool);
+
+	rx_chn->page_pool = pool;
+
+	for (i = 0; i < common->port_num; i++) {
+		rxq = &common->ports[i].xdp_rxq;
+
+		ret = xdp_rxq_info_reg(rxq, common->ports[i].ndev, i, 0);
+		if (ret)
+			goto err;
+
+		ret = xdp_rxq_info_reg_mem_model(rxq, MEM_TYPE_PAGE_POOL, pool);
+		if (ret)
+			goto err;
+	}
+
+	return 0;
+
+err:
+	am65_cpsw_destroy_xdp_rxqs(common);
+	return ret;
+}
+
 static void am65_cpsw_nuss_rx_cleanup(void *data, dma_addr_t desc_dma)
 {
 	struct am65_cpsw_rx_chn *rx_chn = data;
@@ -440,9 +512,40 @@ static void am65_cpsw_nuss_tx_cleanup(void *data, dma_addr_t desc_dma)
 	dev_kfree_skb_any(skb);
 }
 
+static struct sk_buff *am65_cpsw_alloc_skb(struct am65_cpsw_rx_chn *rx_chn,
+					   struct net_device *ndev,
+					   unsigned int len,
+					   int page_idx)
+{
+	struct sk_buff *skb;
+	struct page *page;
+
+	page = page_pool_dev_alloc_pages(rx_chn->page_pool);
+	if (unlikely(!page))
+		return NULL;
+
+	len += AM65_CPSW_HEADROOM;
+
+	skb = build_skb(page_address(page), len);
+	if (unlikely(!skb)) {
+		page_pool_put_full_page(rx_chn->page_pool, page, ndev);
+		rx_chn->pages[page_idx] = NULL;
+		return NULL;
+	}
+
+	skb_reserve(skb, AM65_CPSW_HEADROOM + NET_IP_ALIGN);
+	skb->dev = ndev;
+
+	rx_chn->pages[page_idx] = page;
+
+	return skb;
+}
+
 static int am65_cpsw_nuss_common_open(struct am65_cpsw_common *common)
 {
 	struct am65_cpsw_host *host_p = am65_common_get_host(common);
+	struct am65_cpsw_rx_chn *rx_chn = &common->rx_chns;
+	struct am65_cpsw_tx_chn *tx_chn = common->tx_chns;
 	int port_idx, i, ret, tx;
 	struct sk_buff *skb;
 	u32 val, port_mask;
@@ -505,10 +608,14 @@ static int am65_cpsw_nuss_common_open(struct am65_cpsw_common *common)
 
 	am65_cpsw_qos_tx_p0_rate_init(common);
 
-	for (i = 0; i < common->rx_chns.descs_num; i++) {
-		skb = __netdev_alloc_skb_ip_align(NULL,
-						  AM65_CPSW_MAX_PACKET_SIZE,
-						  GFP_KERNEL);
+	ret = am65_cpsw_create_xdp_rxqs(common);
+	if (ret) {
+		dev_err(common->dev, "Failed to create XDP rx queues\n");
+		return ret;
+	}
+
+	for (i = 0; i < rx_chn->descs_num; i++) {
+		skb = am65_cpsw_alloc_skb(rx_chn, NULL, AM65_CPSW_MAX_PACKET_SIZE, i);
 		if (!skb) {
 			ret = -ENOMEM;
 			dev_err(common->dev, "cannot allocate skb\n");
@@ -531,27 +638,27 @@ static int am65_cpsw_nuss_common_open(struct am65_cpsw_common *common)
 		}
 	}
 
-	ret = k3_udma_glue_enable_rx_chn(common->rx_chns.rx_chn);
+	ret = k3_udma_glue_enable_rx_chn(rx_chn->rx_chn);
 	if (ret) {
 		dev_err(common->dev, "couldn't enable rx chn: %d\n", ret);
 		goto fail_rx;
 	}
 
 	for (tx = 0; tx < common->tx_ch_num; tx++) {
-		ret = k3_udma_glue_enable_tx_chn(common->tx_chns[tx].tx_chn);
+		ret = k3_udma_glue_enable_tx_chn(tx_chn[tx].tx_chn);
 		if (ret) {
 			dev_err(common->dev, "couldn't enable tx chn %d: %d\n",
 				tx, ret);
 			tx--;
 			goto fail_tx;
 		}
-		napi_enable(&common->tx_chns[tx].napi_tx);
+		napi_enable(&tx_chn[tx].napi_tx);
 	}
 
 	napi_enable(&common->napi_rx);
 	if (common->rx_irq_disabled) {
 		common->rx_irq_disabled = false;
-		enable_irq(common->rx_chns.irq);
+		enable_irq(rx_chn->irq);
 	}
 
 	dev_dbg(common->dev, "cpsw_nuss started\n");
@@ -559,22 +666,23 @@ static int am65_cpsw_nuss_common_open(struct am65_cpsw_common *common)
 
 fail_tx:
 	while (tx >= 0) {
-		napi_disable(&common->tx_chns[tx].napi_tx);
-		k3_udma_glue_disable_tx_chn(common->tx_chns[tx].tx_chn);
+		napi_disable(&tx_chn[tx].napi_tx);
+		k3_udma_glue_disable_tx_chn(tx_chn[tx].tx_chn);
 		tx--;
 	}
 
-	k3_udma_glue_disable_rx_chn(common->rx_chns.rx_chn);
+	k3_udma_glue_disable_rx_chn(rx_chn->rx_chn);
 
 fail_rx:
-	k3_udma_glue_reset_rx_chn(common->rx_chns.rx_chn, 0,
-				  &common->rx_chns,
+	k3_udma_glue_reset_rx_chn(rx_chn->rx_chn, 0, rx_chn,
 				  am65_cpsw_nuss_rx_cleanup, 0);
 	return ret;
 }
 
 static int am65_cpsw_nuss_common_stop(struct am65_cpsw_common *common)
 {
+	struct am65_cpsw_rx_chn *rx_chn = &common->rx_chns;
+	struct am65_cpsw_tx_chn *tx_chn = common->tx_chns;
 	int i;
 
 	if (common->usage_count != 1)
@@ -590,26 +698,25 @@ static int am65_cpsw_nuss_common_stop(struct am65_cpsw_common *common)
 	reinit_completion(&common->tdown_complete);
 
 	for (i = 0; i < common->tx_ch_num; i++)
-		k3_udma_glue_tdown_tx_chn(common->tx_chns[i].tx_chn, false);
+		k3_udma_glue_tdown_tx_chn(tx_chn[i].tx_chn, false);
 
 	i = wait_for_completion_timeout(&common->tdown_complete,
 					msecs_to_jiffies(1000));
 	if (!i)
 		dev_err(common->dev, "tx timeout\n");
 	for (i = 0; i < common->tx_ch_num; i++) {
-		napi_disable(&common->tx_chns[i].napi_tx);
-		hrtimer_cancel(&common->tx_chns[i].tx_hrtimer);
+		napi_disable(&tx_chn[i].napi_tx);
+		hrtimer_cancel(&tx_chn[i].tx_hrtimer);
 	}
 
 	for (i = 0; i < common->tx_ch_num; i++) {
-		k3_udma_glue_reset_tx_chn(common->tx_chns[i].tx_chn,
-					  &common->tx_chns[i],
+		k3_udma_glue_reset_tx_chn(tx_chn[i].tx_chn, &tx_chn[i],
 					  am65_cpsw_nuss_tx_cleanup);
-		k3_udma_glue_disable_tx_chn(common->tx_chns[i].tx_chn);
+		k3_udma_glue_disable_tx_chn(tx_chn[i].tx_chn);
 	}
 
 	reinit_completion(&common->tdown_complete);
-	k3_udma_glue_tdown_rx_chn(common->rx_chns.rx_chn, true);
+	k3_udma_glue_tdown_rx_chn(rx_chn->rx_chn, true);
 
 	if (common->pdata.quirks & AM64_CPSW_QUIRK_DMA_RX_TDOWN_IRQ) {
 		i = wait_for_completion_timeout(&common->tdown_complete, msecs_to_jiffies(1000));
@@ -621,17 +728,24 @@ static int am65_cpsw_nuss_common_stop(struct am65_cpsw_common *common)
 	hrtimer_cancel(&common->rx_hrtimer);
 
 	for (i = 0; i < AM65_CPSW_MAX_RX_FLOWS; i++)
-		k3_udma_glue_reset_rx_chn(common->rx_chns.rx_chn, i,
-					  &common->rx_chns,
+		k3_udma_glue_reset_rx_chn(rx_chn->rx_chn, i, rx_chn,
 					  am65_cpsw_nuss_rx_cleanup, !!i);
 
-	k3_udma_glue_disable_rx_chn(common->rx_chns.rx_chn);
+	k3_udma_glue_disable_rx_chn(rx_chn->rx_chn);
 
 	cpsw_ale_stop(common->ale);
 
 	writel(0, common->cpsw_base + AM65_CPSW_REG_CTL);
 	writel(0, common->cpsw_base + AM65_CPSW_REG_STAT_PORT_EN);
 
+	for (i = 0; i < rx_chn->descs_num; i++) {
+		if (rx_chn->pages[i]) {
+			page_pool_put_full_page(rx_chn->page_pool, rx_chn->pages[i], false);
+			rx_chn->pages[i] = NULL;
+		}
+	}
+	am65_cpsw_destroy_xdp_rxqs(common);
+
 	dev_dbg(common->dev, "cpsw_nuss stopped\n");
 	return 0;
 }
@@ -749,6 +863,141 @@ static int am65_cpsw_nuss_ndo_slave_open(struct net_device *ndev)
 	return ret;
 }
 
+static int am65_cpsw_xdp_tx_frame(struct net_device *ndev,
+				  struct am65_cpsw_tx_chn *tx_chn,
+				  struct xdp_frame *xdpf)
+{
+	struct am65_cpsw_common *common = am65_ndev_to_common(ndev);
+	struct am65_cpsw_port *port = am65_ndev_to_port(ndev);
+	struct cppi5_host_desc_t *host_desc;
+	struct netdev_queue *netif_txq;
+	dma_addr_t dma_desc, dma_buf;
+	u32 pkt_len = xdpf->len;
+	void **swdata;
+	int ret;
+
+	host_desc = k3_cppi_desc_pool_alloc(tx_chn->desc_pool);
+	if (unlikely(!host_desc)) {
+		ndev->stats.tx_dropped++;
+		return -ENOMEM;
+	}
+
+	dma_buf = dma_map_single(tx_chn->dma_dev, xdpf->data, pkt_len, DMA_TO_DEVICE);
+	if (unlikely(dma_mapping_error(tx_chn->dma_dev, dma_buf))) {
+		ndev->stats.tx_dropped++;
+		ret = -ENOMEM;
+		goto pool_free;
+	}
+
+	cppi5_hdesc_init(host_desc, CPPI5_INFO0_HDESC_EPIB_PRESENT, AM65_CPSW_NAV_PS_DATA_SIZE);
+	cppi5_hdesc_set_pkttype(host_desc, AM65_CPSW_CPPI_TX_PKT_TYPE);
+	cppi5_hdesc_set_pktlen(host_desc, pkt_len);
+	cppi5_desc_set_pktids(&host_desc->hdr, 0, AM65_CPSW_CPPI_TX_FLOW_ID);
+	cppi5_desc_set_tags_ids(&host_desc->hdr, 0, port->port_id);
+
+	k3_udma_glue_tx_dma_to_cppi5_addr(tx_chn->tx_chn, &dma_buf);
+	cppi5_hdesc_attach_buf(host_desc, dma_buf, pkt_len, dma_buf, pkt_len);
+
+	swdata = cppi5_hdesc_get_swdata(host_desc);
+	*(swdata) = xdpf;
+
+	/* Report BQL before sending the packet */
+	netif_txq = netdev_get_tx_queue(ndev, tx_chn->id);
+	netdev_tx_sent_queue(netif_txq, pkt_len);
+
+	dma_desc = k3_cppi_desc_pool_virt2dma(tx_chn->desc_pool, host_desc);
+	if (AM65_CPSW_IS_CPSW2G(common)) {
+		ret = k3_udma_glue_push_tx_chn(tx_chn->tx_chn, host_desc, dma_desc);
+	} else {
+		spin_lock_bh(&tx_chn->lock);
+		ret = k3_udma_glue_push_tx_chn(tx_chn->tx_chn, host_desc, dma_desc);
+		spin_unlock_bh(&tx_chn->lock);
+	}
+	if (ret) {
+		/* Inform BQL */
+		netdev_tx_completed_queue(netif_txq, 1, pkt_len);
+		ndev->stats.tx_errors++;
+		goto dma_unmap;
+	}
+
+	return 0;
+
+dma_unmap:
+	k3_udma_glue_tx_cppi5_to_dma_addr(tx_chn->tx_chn, &dma_buf);
+	dma_unmap_single(tx_chn->dma_dev, dma_buf, pkt_len, DMA_TO_DEVICE);
+pool_free:
+	k3_cppi_desc_pool_free(tx_chn->desc_pool, host_desc);
+	return ret;
+}
+
+static int am65_cpsw_run_xdp(struct am65_cpsw_common *common, struct am65_cpsw_port *port,
+			     struct xdp_buff *xdp, int page_idx, int cpu, int *len)
+{
+	struct am65_cpsw_rx_chn *rx_chn = &common->rx_chns;
+	struct net_device *ndev = port->ndev;
+	int ret = AM65_CPSW_XDP_CONSUMED;
+	struct am65_cpsw_tx_chn *tx_chn;
+	struct netdev_queue *netif_txq;
+	struct xdp_frame *xdpf;
+	struct bpf_prog *prog;
+	struct page *page;
+	u32 act;
+
+	prog = READ_ONCE(port->xdp_prog);
+	if (!prog)
+		return AM65_CPSW_XDP_PASS;
+
+	act = bpf_prog_run_xdp(prog, xdp);
+	/* XDP prog might have changed packet data and boundaries */
+	*len = xdp->data_end - xdp->data;
+
+	switch (act) {
+	case XDP_PASS:
+		ret = AM65_CPSW_XDP_PASS;
+		goto out;
+	case XDP_TX:
+		tx_chn = &common->tx_chns[cpu % AM65_CPSW_MAX_TX_QUEUES];
+		netif_txq = netdev_get_tx_queue(ndev, tx_chn->id);
+
+		xdpf = xdp_convert_buff_to_frame(xdp);
+		if (unlikely(!xdpf))
+			break;
+
+		__netif_tx_lock(netif_txq, cpu);
+		tx_chn->buf_type = AM65_CPSW_TX_BUF_TYPE_XDP_TX;
+		ret = am65_cpsw_xdp_tx_frame(ndev, tx_chn, xdpf);
+		__netif_tx_unlock(netif_txq);
+		if (ret)
+			break;
+
+		ndev->stats.rx_bytes += *len;
+		ndev->stats.rx_packets++;
+		ret = AM65_CPSW_XDP_CONSUMED;
+		goto out;
+	case XDP_REDIRECT:
+		if (unlikely(xdp_do_redirect(ndev, xdp, prog)))
+			break;
+
+		ndev->stats.rx_bytes += *len;
+		ndev->stats.rx_packets++;
+		goto out;
+	default:
+		bpf_warn_invalid_xdp_action(ndev, prog, act);
+		fallthrough;
+	case XDP_ABORTED:
+		trace_xdp_exception(ndev, prog, act);
+		fallthrough;
+	case XDP_DROP:
+		ndev->stats.rx_dropped++;
+	}
+
+	page = virt_to_head_page(xdp->data);
+	page_pool_recycle_direct(rx_chn->page_pool, page);
+	rx_chn->pages[page_idx] = NULL;
+out:
+	return ret;
+}
+
 static void am65_cpsw_nuss_rx_ts(struct sk_buff *skb, u32 *psdata)
 {
 	struct skb_shared_hwtstamps *ssh;
@@ -795,7 +1044,7 @@ static void am65_cpsw_nuss_rx_csum(struct sk_buff *skb, u32 csum_info)
 }
 
 static int am65_cpsw_nuss_rx_packets(struct am65_cpsw_common *common,
-				     u32 flow_idx)
+				     u32 flow_idx, int cpu)
 {
 	struct am65_cpsw_rx_chn *rx_chn = &common->rx_chns;
 	u32 buf_dma_len, pkt_len, port_id = 0, csum_info;
@@ -806,10 +1055,13 @@ static int am65_cpsw_nuss_rx_packets(struct am65_cpsw_common *common,
 	struct sk_buff *skb, *new_skb;
 	dma_addr_t desc_dma, buf_dma;
 	struct am65_cpsw_port *port;
+	int headroom, page_idx, ret;
 	struct net_device *ndev;
+	struct xdp_buff	xdp;
+	struct page *page;
+	void *pool_addr;
 	void **swdata;
 	u32 *psdata;
-	int ret = 0;
 
 	ret = k3_udma_glue_pop_rx_chn(rx_chn->rx_chn, flow_idx, &desc_dma);
 	if (ret) {
@@ -851,7 +1103,27 @@ static int am65_cpsw_nuss_rx_packets(struct am65_cpsw_common *common,
 
 	k3_cppi_desc_pool_free(rx_chn->desc_pool, desc_rx);
 
-	new_skb = netdev_alloc_skb_ip_align(ndev, AM65_CPSW_MAX_PACKET_SIZE);
+	/* Compute page index */
+	pool_addr = k3_cppi_desc_pool_cpuaddr(rx_chn->desc_pool);
+	page_idx = ((void *)desc_rx - pool_addr) >> rx_chn->dsize_log2;
+
+	if (port->xdp_prog) {
+		xdp_init_buff(&xdp, AM65_CPSW_MAX_PACKET_SIZE, &port->xdp_rxq);
+
+		page = virt_to_page(skb->data);
+		xdp_prepare_buff(&xdp, page_address(page), skb_headroom(skb), pkt_len, false);
+
+		ret = am65_cpsw_run_xdp(common, port, &xdp, page_idx, cpu, &pkt_len);
+		if (ret != AM65_CPSW_XDP_PASS)
+			return ret;
+
+		/* Compute additional headroom to be reserved */
+		headroom = (xdp.data - xdp.data_hard_start) - skb_headroom(skb);
+		skb_reserve(skb, headroom);
+	}
+
+	/* Pass skb to netstack if no XDP prog or returned XDP_PASS */
+	new_skb = am65_cpsw_alloc_skb(rx_chn, ndev, AM65_CPSW_MAX_PACKET_SIZE, page_idx);
 	if (new_skb) {
 		ndev_priv = netdev_priv(ndev);
 		am65_cpsw_nuss_set_offload_fwd_mark(skb, ndev_priv->offload_fwd_mark);
@@ -901,6 +1173,7 @@ static int am65_cpsw_nuss_rx_poll(struct napi_struct *napi_rx, int budget)
 {
 	struct am65_cpsw_common *common = am65_cpsw_napi_to_common(napi_rx);
 	int flow = AM65_CPSW_MAX_RX_FLOWS;
+	int cpu = smp_processor_id();
 	int cur_budget, ret;
 	int num_rx = 0;
 
@@ -909,7 +1182,7 @@ static int am65_cpsw_nuss_rx_poll(struct napi_struct *napi_rx, int budget)
 		cur_budget = budget - num_rx;
 
 		while (cur_budget--) {
-			ret = am65_cpsw_nuss_rx_packets(common, flow);
+			ret = am65_cpsw_nuss_rx_packets(common, flow, cpu);
 			if (ret)
 				break;
 			num_rx++;
@@ -938,8 +1211,8 @@ static int am65_cpsw_nuss_rx_poll(struct napi_struct *napi_rx, int budget)
 }
 
 static struct sk_buff *
-am65_cpsw_nuss_tx_compl_packet(struct am65_cpsw_tx_chn *tx_chn,
-			       dma_addr_t desc_dma)
+am65_cpsw_nuss_tx_compl_packet_skb(struct am65_cpsw_tx_chn *tx_chn,
+				   dma_addr_t desc_dma)
 {
 	struct am65_cpsw_ndev_priv *ndev_priv;
 	struct am65_cpsw_ndev_stats *stats;
@@ -968,6 +1241,39 @@ am65_cpsw_nuss_tx_compl_packet(struct am65_cpsw_tx_chn *tx_chn,
 	return skb;
 }
 
+static struct xdp_frame *
+am65_cpsw_nuss_tx_compl_packet_xdp(struct am65_cpsw_common *common,
+				   struct am65_cpsw_tx_chn *tx_chn,
+				   dma_addr_t desc_dma,
+				   struct net_device **ndev)
+{
+	struct am65_cpsw_ndev_priv *ndev_priv;
+	struct am65_cpsw_ndev_stats *stats;
+	struct cppi5_host_desc_t *desc_tx;
+	struct am65_cpsw_port *port;
+	struct xdp_frame *xdpf;
+	u32 port_id = 0;
+	void **swdata;
+
+	desc_tx = k3_cppi_desc_pool_dma2virt(tx_chn->desc_pool, desc_dma);
+	cppi5_desc_get_tags_ids(&desc_tx->hdr, NULL, &port_id);
+	swdata = cppi5_hdesc_get_swdata(desc_tx);
+	xdpf = *(swdata);
+	am65_cpsw_nuss_xmit_free(tx_chn, desc_tx);
+
+	port = am65_common_get_port(common, port_id);
+	*ndev = port->ndev;
+
+	ndev_priv = netdev_priv(*ndev);
+	stats = this_cpu_ptr(ndev_priv->stats);
+	u64_stats_update_begin(&stats->syncp);
+	stats->tx_packets++;
+	stats->tx_bytes += xdpf->len;
+	u64_stats_update_end(&stats->syncp);
+
+	return xdpf;
+}
+
 static void am65_cpsw_nuss_tx_wake(struct am65_cpsw_tx_chn *tx_chn, struct net_device *ndev,
 				   struct netdev_queue *netif_txq)
 {
@@ -993,6 +1299,7 @@ static int am65_cpsw_nuss_tx_compl_packets(struct am65_cpsw_common *common,
 	struct netdev_queue *netif_txq;
 	unsigned int total_bytes = 0;
 	struct net_device *ndev;
+	struct xdp_frame *xdpf;
 	struct sk_buff *skb;
 	dma_addr_t desc_dma;
 	int res, num_tx = 0;
@@ -1013,10 +1320,19 @@ static int am65_cpsw_nuss_tx_compl_packets(struct am65_cpsw_common *common,
 			break;
 		}
 
-		skb = am65_cpsw_nuss_tx_compl_packet(tx_chn, desc_dma);
-		total_bytes = skb->len;
-		ndev = skb->dev;
-		napi_consume_skb(skb, budget);
+		if (tx_chn->buf_type == AM65_CPSW_TX_BUF_TYPE_SKB) {
+			skb = am65_cpsw_nuss_tx_compl_packet_skb(tx_chn, desc_dma);
+			ndev = skb->dev;
+			total_bytes = skb->len;
+			napi_consume_skb(skb, budget);
+		} else {
+			xdpf = am65_cpsw_nuss_tx_compl_packet_xdp(common, tx_chn, desc_dma, &ndev);
+			total_bytes = xdpf->len;
+			if (tx_chn->buf_type == AM65_CPSW_TX_BUF_TYPE_XDP_TX)
+				xdp_return_frame_rx_napi(xdpf);
+			else
+				xdp_return_frame(xdpf);
+		}
 		num_tx++;
 
 		netif_txq = netdev_get_tx_queue(ndev, chn);
@@ -1039,6 +1355,7 @@ static int am65_cpsw_nuss_tx_compl_packets_2g(struct am65_cpsw_common *common,
 	struct netdev_queue *netif_txq;
 	unsigned int total_bytes = 0;
 	struct net_device *ndev;
+	struct xdp_frame *xdpf;
 	struct sk_buff *skb;
 	dma_addr_t desc_dma;
 	int res, num_tx = 0;
@@ -1057,11 +1374,19 @@ static int am65_cpsw_nuss_tx_compl_packets_2g(struct am65_cpsw_common *common,
 			break;
 		}
 
-		skb = am65_cpsw_nuss_tx_compl_packet(tx_chn, desc_dma);
-
-		ndev = skb->dev;
-		total_bytes += skb->len;
-		napi_consume_skb(skb, budget);
+		if (tx_chn->buf_type == AM65_CPSW_TX_BUF_TYPE_SKB) {
+			skb = am65_cpsw_nuss_tx_compl_packet_skb(tx_chn, desc_dma);
+			ndev = skb->dev;
+			total_bytes += skb->len;
+			napi_consume_skb(skb, budget);
+		} else {
+			xdpf = am65_cpsw_nuss_tx_compl_packet_xdp(common, tx_chn, desc_dma, &ndev);
+			total_bytes += xdpf->len;
+			if (tx_chn->buf_type == AM65_CPSW_TX_BUF_TYPE_XDP_TX)
+				xdp_return_frame_rx_napi(xdpf);
+			else
+				xdp_return_frame(xdpf);
+		}
 		num_tx++;
 	}
 
@@ -1166,6 +1491,8 @@ static netdev_tx_t am65_cpsw_nuss_ndo_slave_xmit(struct sk_buff *skb,
 	tx_chn = &common->tx_chns[q_idx];
 	netif_txq = netdev_get_tx_queue(ndev, q_idx);
 
+	tx_chn->buf_type = AM65_CPSW_TX_BUF_TYPE_SKB;
+
 	/* Map the linear buffer */
 	buf_dma = dma_map_single(tx_chn->dma_dev, skb->data, pkt_len,
 				 DMA_TO_DEVICE);
@@ -1185,8 +1512,8 @@ static netdev_tx_t am65_cpsw_nuss_ndo_slave_xmit(struct sk_buff *skb,
 
 	cppi5_hdesc_init(first_desc, CPPI5_INFO0_HDESC_EPIB_PRESENT,
 			 AM65_CPSW_NAV_PS_DATA_SIZE);
-	cppi5_desc_set_pktids(&first_desc->hdr, 0, 0x3FFF);
-	cppi5_hdesc_set_pkttype(first_desc, 0x7);
+	cppi5_desc_set_pktids(&first_desc->hdr, 0, AM65_CPSW_CPPI_TX_FLOW_ID);
+	cppi5_hdesc_set_pkttype(first_desc, AM65_CPSW_CPPI_TX_PKT_TYPE);
 	cppi5_desc_set_tags_ids(&first_desc->hdr, 0, port->port_id);
 
 	k3_udma_glue_tx_dma_to_cppi5_addr(tx_chn->tx_chn, &buf_dma);
@@ -1488,6 +1815,58 @@ static void am65_cpsw_nuss_ndo_get_stats(struct net_device *dev,
 	stats->tx_dropped	= dev->stats.tx_dropped;
 }
 
+static int am65_cpsw_xdp_prog_setup(struct net_device *ndev, struct bpf_prog *prog)
+{
+	struct am65_cpsw_port *port = am65_ndev_to_port(ndev);
+	bool running = netif_running(ndev);
+	struct bpf_prog *old_prog;
+
+	if (running)
+		am65_cpsw_nuss_ndo_slave_stop(ndev);
+
+	old_prog = xchg(&port->xdp_prog, prog);
+	if (old_prog)
+		bpf_prog_put(old_prog);
+
+	if (running)
+		return am65_cpsw_nuss_ndo_slave_open(ndev);
+
+	return 0;
+}
+
+static int am65_cpsw_ndo_bpf(struct net_device *ndev, struct netdev_bpf *bpf)
+{
+	switch (bpf->command) {
+	case XDP_SETUP_PROG:
+		return am65_cpsw_xdp_prog_setup(ndev, bpf->prog);
+	default:
+		return -EINVAL;
+	}
+}
+
+static int am65_cpsw_ndo_xdp_xmit(struct net_device *ndev, int n,
+				  struct xdp_frame **frames, u32 flags)
+{
+	struct am65_cpsw_tx_chn *tx_chn;
+	struct netdev_queue *netif_txq;
+	int cpu = smp_processor_id();
+	int i, nxmit = 0;
+
+	tx_chn = &am65_ndev_to_common(ndev)->tx_chns[cpu % AM65_CPSW_MAX_TX_QUEUES];
+	netif_txq = netdev_get_tx_queue(ndev, tx_chn->id);
+
+	__netif_tx_lock(netif_txq, cpu);
+	tx_chn->buf_type = AM65_CPSW_TX_BUF_TYPE_XDP_NDO;
+	for (i = 0; i < n; i++) {
+		if (am65_cpsw_xdp_tx_frame(ndev, tx_chn, frames[i]))
+			break;
+		nxmit++;
+	}
+	__netif_tx_unlock(netif_txq);
+
+	return nxmit;
+}
+
 static const struct net_device_ops am65_cpsw_nuss_netdev_ops = {
 	.ndo_open		= am65_cpsw_nuss_ndo_slave_open,
 	.ndo_stop		= am65_cpsw_nuss_ndo_slave_stop,
@@ -1502,6 +1881,8 @@ static const struct net_device_ops am65_cpsw_nuss_netdev_ops = {
 	.ndo_eth_ioctl		= am65_cpsw_nuss_ndo_slave_ioctl,
 	.ndo_setup_tc           = am65_cpsw_qos_ndo_setup_tc,
 	.ndo_set_tx_maxrate	= am65_cpsw_qos_ndo_tx_p0_set_maxrate,
+	.ndo_bpf		= am65_cpsw_ndo_bpf,
+	.ndo_xdp_xmit		= am65_cpsw_ndo_xdp_xmit,
 };
 
 static void am65_cpsw_disable_phy(struct phy *phy)
@@ -1816,6 +2197,8 @@ static int am65_cpsw_nuss_init_tx_chns(struct am65_cpsw_common *common)
 			goto err;
 		}
 
+		tx_chn->buf_type = AM65_CPSW_TX_BUF_TYPE_SKB;
+
 		tx_chn->irq = k3_udma_glue_tx_get_irq(tx_chn->tx_chn);
 		if (tx_chn->irq < 0) {
 			dev_err(dev, "Failed to get tx dma irq %d\n",
@@ -1862,8 +2245,8 @@ static void am65_cpsw_nuss_free_rx_chns(void *data)
 static void am65_cpsw_nuss_remove_rx_chns(void *data)
 {
 	struct am65_cpsw_common *common = data;
-	struct am65_cpsw_rx_chn *rx_chn;
 	struct device *dev = common->dev;
+	struct am65_cpsw_rx_chn *rx_chn;
 
 	rx_chn = &common->rx_chns;
 	devm_remove_action(dev, am65_cpsw_nuss_free_rx_chns, common);
@@ -1873,11 +2256,7 @@ static void am65_cpsw_nuss_remove_rx_chns(void *data)
 
 	netif_napi_del(&common->napi_rx);
 
-	if (!IS_ERR_OR_NULL(rx_chn->desc_pool))
-		k3_cppi_desc_pool_destroy(rx_chn->desc_pool);
-
-	if (!IS_ERR_OR_NULL(rx_chn->rx_chn))
-		k3_udma_glue_release_rx_chn(rx_chn->rx_chn);
+	am65_cpsw_nuss_free_rx_chns(common);
 
 	common->rx_flow_id_base = -1;
 }
@@ -1888,6 +2267,7 @@ static int am65_cpsw_nuss_init_rx_chns(struct am65_cpsw_common *common)
 	struct k3_udma_glue_rx_channel_cfg rx_cfg = { 0 };
 	u32  max_desc_num = AM65_CPSW_MAX_RX_DESC;
 	struct device *dev = common->dev;
+	u32 hdesc_size_out;
 	u32 hdesc_size;
 	u32 fdqring_id;
 	int i, ret = 0;
@@ -1920,6 +2300,15 @@ static int am65_cpsw_nuss_init_rx_chns(struct am65_cpsw_common *common)
 		goto err;
 	}
 
+	hdesc_size_out = k3_cppi_desc_pool_desc_size(rx_chn->desc_pool);
+	rx_chn->dsize_log2 = __fls(hdesc_size_out);
+	WARN_ON(hdesc_size_out != (1 << rx_chn->dsize_log2));
+
+	rx_chn->page_pool = NULL;
+	rx_chn->pages = devm_kcalloc(dev, rx_chn->descs_num, sizeof(*rx_chn->pages), GFP_KERNEL);
+	if (!rx_chn->pages)
+		return -ENOMEM;
+
 	common->rx_flow_id_base =
 			k3_udma_glue_rx_get_flow_id_base(rx_chn->rx_chn);
 	dev_info(dev, "set new flow-id-base %u\n", common->rx_flow_id_base);
@@ -2252,6 +2641,9 @@ am65_cpsw_nuss_init_port_ndev(struct am65_cpsw_common *common, u32 port_idx)
 				  NETIF_F_HW_TC;
 	port->ndev->features = port->ndev->hw_features |
 			       NETIF_F_HW_VLAN_CTAG_FILTER;
+	port->ndev->xdp_features = NETDEV_XDP_ACT_BASIC |
+				   NETDEV_XDP_ACT_REDIRECT |
+				   NETDEV_XDP_ACT_NDO_XMIT;
 	port->ndev->vlan_features |=  NETIF_F_SG;
 	port->ndev->netdev_ops = &am65_cpsw_nuss_netdev_ops;
 	port->ndev->ethtool_ops = &am65_cpsw_ethtool_ops_slave;
@@ -2315,6 +2707,8 @@ am65_cpsw_nuss_init_port_ndev(struct am65_cpsw_common *common, u32 port_idx)
 	if (ret)
 		dev_err(dev, "failed to add percpu stat free action %d\n", ret);
 
+	port->xdp_prog = NULL;
+
 	if (!common->dma_ndev)
 		common->dma_ndev = port->ndev;
 
@@ -2940,9 +3334,9 @@ static int am65_cpsw_nuss_probe(struct platform_device *pdev)
 	struct device_node *node;
 	struct resource *res;
 	struct clk *clk;
+	int ale_entries;
 	u64 id_temp;
 	int ret, i;
-	int ale_entries;
 
 	common = devm_kzalloc(dev, sizeof(struct am65_cpsw_common), GFP_KERNEL);
 	if (!common)
@@ -3154,10 +3548,10 @@ static int am65_cpsw_nuss_suspend(struct device *dev)
 static int am65_cpsw_nuss_resume(struct device *dev)
 {
 	struct am65_cpsw_common *common = dev_get_drvdata(dev);
+	struct am65_cpsw_host *host_p = am65_common_get_host(common);
 	struct am65_cpsw_port *port;
 	struct net_device *ndev;
 	int i, ret;
-	struct am65_cpsw_host *host_p = am65_common_get_host(common);
 
 	ret = am65_cpsw_nuss_init_tx_chns(common);
 	if (ret)
diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.h b/drivers/net/ethernet/ti/am65-cpsw-nuss.h
index 7da0492dc091..5ee5b469d85a 100644
--- a/drivers/net/ethernet/ti/am65-cpsw-nuss.h
+++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.h
@@ -14,6 +14,7 @@
 #include <linux/platform_device.h>
 #include <linux/soc/ti/k3-ringacc.h>
 #include <net/devlink.h>
+#include <net/xdp.h>
 #include "am65-cpsw-qos.h"
 
 struct am65_cpts;
@@ -56,10 +57,18 @@ struct am65_cpsw_port {
 	bool				rx_ts_enabled;
 	struct am65_cpsw_qos		qos;
 	struct devlink_port		devlink_port;
+	struct bpf_prog			*xdp_prog;
+	struct xdp_rxq_info		xdp_rxq;
 	/* Only for suspend resume context */
 	u32				vid_context;
 };
 
+enum am65_cpsw_tx_buf_type {
+	AM65_CPSW_TX_BUF_TYPE_SKB,
+	AM65_CPSW_TX_BUF_TYPE_XDP_TX,
+	AM65_CPSW_TX_BUF_TYPE_XDP_NDO,
+};
+
 struct am65_cpsw_host {
 	struct am65_cpsw_common		*common;
 	void __iomem			*port_base;
@@ -74,6 +83,7 @@ struct am65_cpsw_tx_chn {
 	struct am65_cpsw_common	*common;
 	struct k3_cppi_desc_pool *desc_pool;
 	struct k3_udma_glue_tx_channel *tx_chn;
+	enum am65_cpsw_tx_buf_type buf_type;
 	spinlock_t lock; /* protect TX rings in multi-port mode */
 	struct hrtimer tx_hrtimer;
 	unsigned long tx_pace_timeout;
@@ -89,7 +99,10 @@ struct am65_cpsw_rx_chn {
 	struct device *dma_dev;
 	struct k3_cppi_desc_pool *desc_pool;
 	struct k3_udma_glue_rx_channel *rx_chn;
+	struct page_pool *page_pool;
+	struct page **pages;
 	u32 descs_num;
+	unsigned char dsize_log2;
 	int irq;
 };
 

-- 
2.37.3

Re: [PATCH v2 2/2] net: ethernet: ti: am65-cpsw: Add minimal XDP support

[Andrew Lunn]

On Fri, Mar 01, 2024 at 04:02:53PM +0100, Julien Panis wrote:
> This patch adds XDP (eXpress Data Path) support to TI AM65 CPSW
> Ethernet driver. The following features are implemented:
> - NETDEV_XDP_ACT_BASIC (XDP_PASS, XDP_TX, XDP_DROP, XDP_ABORTED)
> - NETDEV_XDP_ACT_REDIRECT (XDP_REDIRECT)
> - NETDEV_XDP_ACT_NDO_XMIT (ndo_xdp_xmit callback)
> 
> The page pool memory model is used to get better performance.

Do you have any benchmark numbers? It should help with none XDP
traffic as well. So maybe iperf numbers before and after?

	Andrew

Re: [PATCH v2 2/2] net: ethernet: ti: am65-cpsw: Add minimal XDP support

[Julien Panis]

On 3/1/24 17:38, Andrew Lunn wrote:
> On Fri, Mar 01, 2024 at 04:02:53PM +0100, Julien Panis wrote:
>> This patch adds XDP (eXpress Data Path) support to TI AM65 CPSW
>> Ethernet driver. The following features are implemented:
>> - NETDEV_XDP_ACT_BASIC (XDP_PASS, XDP_TX, XDP_DROP, XDP_ABORTED)
>> - NETDEV_XDP_ACT_REDIRECT (XDP_REDIRECT)
>> - NETDEV_XDP_ACT_NDO_XMIT (ndo_xdp_xmit callback)
>>
>> The page pool memory model is used to get better performance.
> Do you have any benchmark numbers? It should help with none XDP
> traffic as well. So maybe iperf numbers before and after?
>
> 	Andrew

OK, I will add benchmark numbers in the next version.

I will also fix a potential issue with TX buffer type, which is not properly
handled in this v2. It should be set for each buffer, I think (instead of just
being set for the tx channel before initiating xmit).

Julien

Re: [PATCH v2 2/2] net: ethernet: ti: am65-cpsw: Add minimal XDP support

[Julien Panis]

On 3/1/24 17:38, Andrew Lunn wrote:
> On Fri, Mar 01, 2024 at 04:02:53PM +0100, Julien Panis wrote:
>> This patch adds XDP (eXpress Data Path) support to TI AM65 CPSW
>> Ethernet driver. The following features are implemented:
>> - NETDEV_XDP_ACT_BASIC (XDP_PASS, XDP_TX, XDP_DROP, XDP_ABORTED)
>> - NETDEV_XDP_ACT_REDIRECT (XDP_REDIRECT)
>> - NETDEV_XDP_ACT_NDO_XMIT (ndo_xdp_xmit callback)
>>
>> The page pool memory model is used to get better performance.
> Do you have any benchmark numbers? It should help with none XDP
> traffic as well. So maybe iperf numbers before and after?
>
> 	Andrew

Argh...Houston, we have a problem. I checked my v3, which is ready for
submission, with iperf3:
1) Before = without page pool -> 500 MBits/sec
2) After = with page pool -> 442 MBits/sec
-> ~ 10% worse with page pool here.

Unless the difference is not due to page pool. Maybe there's something else
which is not good in my patch. I'm going to send the v3 which uses page pool,
hopefully someone will find out something suspicious. Meanwhile, I'll carry on
investigating: I'll check the results with my patch, by removing only the using of
page pool.

Julien

Re: [PATCH v2 2/2] net: ethernet: ti: am65-cpsw: Add minimal XDP support

[Andrew Lunn]

On Tue, Mar 05, 2024 at 11:46:00AM +0100, Julien Panis wrote:
> On 3/1/24 17:38, Andrew Lunn wrote:
> > On Fri, Mar 01, 2024 at 04:02:53PM +0100, Julien Panis wrote:
> > > This patch adds XDP (eXpress Data Path) support to TI AM65 CPSW
> > > Ethernet driver. The following features are implemented:
> > > - NETDEV_XDP_ACT_BASIC (XDP_PASS, XDP_TX, XDP_DROP, XDP_ABORTED)
> > > - NETDEV_XDP_ACT_REDIRECT (XDP_REDIRECT)
> > > - NETDEV_XDP_ACT_NDO_XMIT (ndo_xdp_xmit callback)
> > > 
> > > The page pool memory model is used to get better performance.
> > Do you have any benchmark numbers? It should help with none XDP
> > traffic as well. So maybe iperf numbers before and after?
> > 
> > 	Andrew
> 
> Argh...Houston, we have a problem. I checked my v3, which is ready for
> submission, with iperf3:
> 1) Before = without page pool -> 500 MBits/sec
> 2) After = with page pool -> 442 MBits/sec
> -> ~ 10% worse with page pool here.
> 
> Unless the difference is not due to page pool. Maybe there's something else
> which is not good in my patch. I'm going to send the v3 which uses page pool,
> hopefully someone will find out something suspicious. Meanwhile, I'll carry on
> investigating: I'll check the results with my patch, by removing only the using of
> page pool.

You can also go the other way. First add page pool support. For the
FEC, that improved its performance. Then add XDP, which i think
decreased the performance a little. It is extra processing in the hot
path, so a little loss is not unsurprising.

What tends to be expensive with ARM is cache invalidation and
flush. So make sure you have the lengths correct. You don't want to
operate on more memory than necessary. No point flushing the full MTU
for a 64 byte TCP ACK, etc.

      Andrew

Re: [PATCH v2 2/2] net: ethernet: ti: am65-cpsw: Add minimal XDP support

[Julien Panis]

On 3/5/24 14:28, Andrew Lunn wrote:
> On Tue, Mar 05, 2024 at 11:46:00AM +0100, Julien Panis wrote:
>> On 3/1/24 17:38, Andrew Lunn wrote:
>>> On Fri, Mar 01, 2024 at 04:02:53PM +0100, Julien Panis wrote:
>>>> This patch adds XDP (eXpress Data Path) support to TI AM65 CPSW
>>>> Ethernet driver. The following features are implemented:
>>>> - NETDEV_XDP_ACT_BASIC (XDP_PASS, XDP_TX, XDP_DROP, XDP_ABORTED)
>>>> - NETDEV_XDP_ACT_REDIRECT (XDP_REDIRECT)
>>>> - NETDEV_XDP_ACT_NDO_XMIT (ndo_xdp_xmit callback)
>>>>
>>>> The page pool memory model is used to get better performance.
>>> Do you have any benchmark numbers? It should help with none XDP
>>> traffic as well. So maybe iperf numbers before and after?
>>>
>>> 	Andrew
>> Argh...Houston, we have a problem. I checked my v3, which is ready for
>> submission, with iperf3:
>> 1) Before = without page pool -> 500 MBits/sec
>> 2) After = with page pool -> 442 MBits/sec
>> -> ~ 10% worse with page pool here.
>>
>> Unless the difference is not due to page pool. Maybe there's something else
>> which is not good in my patch. I'm going to send the v3 which uses page pool,
>> hopefully someone will find out something suspicious. Meanwhile, I'll carry on
>> investigating: I'll check the results with my patch, by removing only the using of
>> page pool.
> You can also go the other way. First add page pool support. For the
> FEC, that improved its performance. Then add XDP, which i think
> decreased the performance a little. It is extra processing in the hot
> path, so a little loss is not unsurprising.
>
> What tends to be expensive with ARM is cache invalidation and
> flush. So make sure you have the lengths correct. You don't want to
> operate on more memory than necessary. No point flushing the full MTU
> for a 64 byte TCP ACK, etc.
>
>        Andrew

I changed back code step by step and could find what makes a significant
difference. Here are the main tests achieved (results in Mbits/sec):

1) Page pool without XDP code -> res = 442
Conclusion: No difference with or without XDP code.

2) From 1), page pool removed and replaced by previous memory model
based on dev_alloc_page() function -> res =418
Conclusion: Your advice was good, that's better with page pool. :)

3) From 2), am65_cpsw_alloc_skb() function removed and replaced by
netdev_alloc_skb_ip_align(), as used by the driver before -> res = 506
Conclusion: Here is where the loss comes from.
IOW, My am65_cpsw_alloc_skb() function is not good.

Initially, I mainly created this 'custom' am65_cpsw_alloc_skb() function
because I thought that none of XDP memory models could be used along
with netdev_alloc_skb_ip_align() function. Was I wrong ?
By creating this custom am65_cpsw_alloc_skb(), I also wanted to handle
the way headroom is reserved differently.

Julien

Re: [PATCH v2 2/2] net: ethernet: ti: am65-cpsw: Add minimal XDP support

[Andrew Lunn]

> 3) From 2), am65_cpsw_alloc_skb() function removed and replaced by
> netdev_alloc_skb_ip_align(), as used by the driver before -> res = 506
> Conclusion: Here is where the loss comes from.
> IOW, My am65_cpsw_alloc_skb() function is not good.
> 
> Initially, I mainly created this 'custom' am65_cpsw_alloc_skb() function
> because I thought that none of XDP memory models could be used along
> with netdev_alloc_skb_ip_align() function. Was I wrong ?
> By creating this custom am65_cpsw_alloc_skb(), I also wanted to handle
> the way headroom is reserved differently.

What is special about your device? Why would
netdev_alloc_skb_ip_align() not work?

	Andrew

Re: [PATCH v2 2/2] net: ethernet: ti: am65-cpsw: Add minimal XDP support

[Julien Panis]

On 3/5/24 17:43, Andrew Lunn wrote:
>> 3) From 2), am65_cpsw_alloc_skb() function removed and replaced by
>> netdev_alloc_skb_ip_align(), as used by the driver before -> res = 506
>> Conclusion: Here is where the loss comes from.
>> IOW, My am65_cpsw_alloc_skb() function is not good.
>>
>> Initially, I mainly created this 'custom' am65_cpsw_alloc_skb() function
>> because I thought that none of XDP memory models could be used along
>> with netdev_alloc_skb_ip_align() function. Was I wrong ?
>> By creating this custom am65_cpsw_alloc_skb(), I also wanted to handle
>> the way headroom is reserved differently.
> What is special about your device? Why would
> netdev_alloc_skb_ip_align() not work?
>
> 	Andrew

Nothing special about my device, I just misunderstood.

Regarding page pool, I now have better performance.
Two things were missing:
- I did not call skb_mark_for_recycle(), so pages were freed instead of
being recycled !
- In page_pool_params, that's better when I specify the "napi" parameter.

Performance improvement is not that impressive, but it's better:
505 Mbits/sec (with page pool) instead of 495 Mbits/sec (without).
There is a ~ 5 Mbits/sec loss due to additional processing in the path, for XDP stuffs.
So, the difference in favor of page pool using is ~ 15 Mbits/sec.

I'll send a v4 soon.

Julien