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From:   Horatiu Vultur <horatiu.vultur@microchip.com>
To:     <netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <bpf@vger.kernel.org>
CC:     <davem@davemloft.net>, <edumazet@google.com>, <kuba@kernel.org>,
        <pabeni@redhat.com>, <ast@kernel.org>, <daniel@iogearbox.net>,
        <hawk@kernel.org>, <john.fastabend@gmail.com>,
        <UNGLinuxDriver@microchip.com>,
        Horatiu Vultur <horatiu.vultur@microchip.com>
Subject: [PATCH net-next v3 7/7] net: lan966x: Add support for XDP_REDIRECT
Date:   Mon, 21 Nov 2022 22:28:50 +0100
Message-ID: <20221121212850.3212649-8-horatiu.vultur@microchip.com>
In-Reply-To: <20221121212850.3212649-1-horatiu.vultur@microchip.com>
References: <20221121212850.3212649-1-horatiu.vultur@microchip.com>
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Extend lan966x XDP support with the action XDP_REDIRECT. This is similar
with the XDP_TX, so a lot of functionality can be reused.

Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
---
 .../ethernet/microchip/lan966x/lan966x_fdma.c | 83 +++++++++++++++----
 .../ethernet/microchip/lan966x/lan966x_main.c |  1 +
 .../ethernet/microchip/lan966x/lan966x_main.h | 10 ++-
 .../ethernet/microchip/lan966x/lan966x_xdp.c  | 31 ++++++-
 4 files changed, 109 insertions(+), 16 deletions(-)

diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c b/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c
index b14fdb8e15e22..81dc27d8f8963 100644
--- a/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c
+++ b/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0+
 
 #include <linux/bpf.h>
+#include <linux/filter.h>
 
 #include "lan966x_main.h"
 
@@ -391,11 +392,14 @@ static void lan966x_fdma_tx_clear_buf(struct lan966x *lan966x, int weight)
 {
 	struct lan966x_tx *tx = &lan966x->tx;
 	struct lan966x_tx_dcb_buf *dcb_buf;
+	struct xdp_frame_bulk bq;
 	struct lan966x_db *db;
 	unsigned long flags;
 	bool clear = false;
 	int i;
 
+	xdp_frame_bulk_init(&bq);
+
 	spin_lock_irqsave(&lan966x->tx_lock, flags);
 	for (i = 0; i < FDMA_DCB_MAX; ++i) {
 		dcb_buf = &tx->dcbs_buf[i];
@@ -421,12 +425,24 @@ static void lan966x_fdma_tx_clear_buf(struct lan966x *lan966x, int weight)
 				dev_kfree_skb_any(dcb_buf->skb);
 		}
 
-		if (dcb_buf->xdpf)
-			xdp_return_frame_rx_napi(dcb_buf->xdpf);
+		if (dcb_buf->xdpf) {
+			if (dcb_buf->xdp_ndo)
+				dma_unmap_single(lan966x->dev,
+						 dcb_buf->dma_addr,
+						 dcb_buf->len,
+						 DMA_TO_DEVICE);
+
+			if (dcb_buf->xdp_ndo)
+				xdp_return_frame_bulk(dcb_buf->xdpf, &bq);
+			else
+				xdp_return_frame_rx_napi(dcb_buf->xdpf);
+		}
 
 		clear = true;
 	}
 
+	xdp_flush_frame_bulk(&bq);
+
 	if (clear)
 		lan966x_fdma_wakeup_netdev(lan966x);
 
@@ -533,6 +549,7 @@ static int lan966x_fdma_napi_poll(struct napi_struct *napi, int weight)
 	int dcb_reload = rx->dcb_index;
 	struct lan966x_rx_dcb *old_dcb;
 	struct lan966x_db *db;
+	bool redirect = false;
 	struct sk_buff *skb;
 	struct page *page;
 	int counter = 0;
@@ -558,6 +575,10 @@ static int lan966x_fdma_napi_poll(struct napi_struct *napi, int weight)
 		case FDMA_TX:
 			lan966x_fdma_rx_advance_dcb(rx);
 			continue;
+		case FDMA_REDIRECT:
+			lan966x_fdma_rx_advance_dcb(rx);
+			redirect = true;
+			continue;
 		case FDMA_DROP:
 			lan966x_fdma_rx_free_page(rx);
 			lan966x_fdma_rx_advance_dcb(rx);
@@ -594,6 +615,9 @@ static int lan966x_fdma_napi_poll(struct napi_struct *napi, int weight)
 	if (counter < weight && napi_complete_done(napi, counter))
 		lan_wr(0xff, lan966x, FDMA_INTR_DB_ENA);
 
+	if (redirect)
+		xdp_do_flush();
+
 	return counter;
 }
 
@@ -681,7 +705,8 @@ static void lan966x_fdma_tx_start(struct lan966x_tx *tx, int next_to_use)
 
 int lan966x_fdma_xmit_xdpf(struct lan966x_port *port,
 			   struct xdp_frame *xdpf,
-			   struct page *page)
+			   struct page *page,
+			   bool dma_map)
 {
 	struct lan966x *lan966x = port->lan966x;
 	struct lan966x_tx_dcb_buf *next_dcb_buf;
@@ -702,24 +727,53 @@ int lan966x_fdma_xmit_xdpf(struct lan966x_port *port,
 	}
 
 	/* Generate new IFH */
-	ifh = page_address(page) + XDP_PACKET_HEADROOM;
-	memset(ifh, 0x0, sizeof(__be32) * IFH_LEN);
-	lan966x_ifh_set_bypass(ifh, 1);
-	lan966x_ifh_set_port(ifh, BIT_ULL(port->chip_port));
+	if (dma_map) {
+		if (xdpf->headroom < IFH_LEN_BYTES) {
+			ret = NETDEV_TX_OK;
+			goto out;
+		}
 
-	dma_addr = page_pool_get_dma_addr(page);
-	dma_sync_single_for_device(lan966x->dev, dma_addr + XDP_PACKET_HEADROOM,
-				   xdpf->len + IFH_LEN_BYTES,
-				   DMA_TO_DEVICE);
+		ifh = xdpf->data - IFH_LEN_BYTES;
+		memset(ifh, 0x0, sizeof(__be32) * IFH_LEN);
+		lan966x_ifh_set_bypass(ifh, 1);
+		lan966x_ifh_set_port(ifh, BIT_ULL(port->chip_port));
+
+		dma_addr = dma_map_single(lan966x->dev,
+					  xdpf->data - IFH_LEN_BYTES,
+					  xdpf->len + IFH_LEN_BYTES,
+					  DMA_TO_DEVICE);
+		if (dma_mapping_error(lan966x->dev, dma_addr)) {
+			ret = NETDEV_TX_OK;
+			goto out;
+		}
 
-	/* Setup next dcb */
-	lan966x_fdma_tx_setup_dcb(tx, next_to_use, xdpf->len + IFH_LEN_BYTES,
-				  dma_addr + XDP_PACKET_HEADROOM);
+		/* Setup next dcb */
+		lan966x_fdma_tx_setup_dcb(tx, next_to_use,
+					  xdpf->len + IFH_LEN_BYTES,
+					  dma_addr);
+	} else {
+		ifh = page_address(page) + XDP_PACKET_HEADROOM;
+		memset(ifh, 0x0, sizeof(__be32) * IFH_LEN);
+		lan966x_ifh_set_bypass(ifh, 1);
+		lan966x_ifh_set_port(ifh, BIT_ULL(port->chip_port));
+
+		dma_addr = page_pool_get_dma_addr(page);
+		dma_sync_single_for_device(lan966x->dev,
+					   dma_addr + XDP_PACKET_HEADROOM,
+					   xdpf->len + IFH_LEN_BYTES,
+					   DMA_TO_DEVICE);
+
+		/* Setup next dcb */
+		lan966x_fdma_tx_setup_dcb(tx, next_to_use,
+					  xdpf->len + IFH_LEN_BYTES,
+					  dma_addr + XDP_PACKET_HEADROOM);
+	}
 
 	/* Fill up the buffer */
 	next_dcb_buf = &tx->dcbs_buf[next_to_use];
 	next_dcb_buf->skb = NULL;
 	next_dcb_buf->xdpf = xdpf;
+	next_dcb_buf->xdp_ndo = dma_map;
 	next_dcb_buf->len = xdpf->len + IFH_LEN_BYTES;
 	next_dcb_buf->dma_addr = dma_addr;
 	next_dcb_buf->used = true;
@@ -792,6 +846,7 @@ int lan966x_fdma_xmit(struct sk_buff *skb, __be32 *ifh, struct net_device *dev)
 	next_dcb_buf = &tx->dcbs_buf[next_to_use];
 	next_dcb_buf->skb = skb;
 	next_dcb_buf->xdpf = NULL;
+	next_dcb_buf->xdp_ndo = false;
 	next_dcb_buf->len = skb->len;
 	next_dcb_buf->dma_addr = dma_addr;
 	next_dcb_buf->used = true;
diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_main.c b/drivers/net/ethernet/microchip/lan966x/lan966x_main.c
index 0b7707306da26..0aed244826d39 100644
--- a/drivers/net/ethernet/microchip/lan966x/lan966x_main.c
+++ b/drivers/net/ethernet/microchip/lan966x/lan966x_main.c
@@ -469,6 +469,7 @@ static const struct net_device_ops lan966x_port_netdev_ops = {
 	.ndo_eth_ioctl			= lan966x_port_ioctl,
 	.ndo_setup_tc			= lan966x_tc_setup,
 	.ndo_bpf			= lan966x_xdp,
+	.ndo_xdp_xmit			= lan966x_xdp_xmit,
 };
 
 bool lan966x_netdevice_check(const struct net_device *dev)
diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_main.h b/drivers/net/ethernet/microchip/lan966x/lan966x_main.h
index e303a12daf88a..ed4adeae553d3 100644
--- a/drivers/net/ethernet/microchip/lan966x/lan966x_main.h
+++ b/drivers/net/ethernet/microchip/lan966x/lan966x_main.h
@@ -106,12 +106,14 @@ enum macaccess_entry_type {
  * FDMA_ERROR, something went wrong, stop getting more frames
  * FDMA_DROP, frame is dropped, but continue to get more frames
  * FDMA_TX, frame is given to TX, but continue to get more frames
+ * FDMA_REDIRECT, frame is given to TX, but continue to get more frames
  */
 enum lan966x_fdma_action {
 	FDMA_PASS = 0,
 	FDMA_ERROR,
 	FDMA_DROP,
 	FDMA_TX,
+	FDMA_REDIRECT,
 };
 
 struct lan966x_port;
@@ -178,6 +180,7 @@ struct lan966x_tx_dcb_buf {
 	struct net_device *dev;
 	struct sk_buff *skb;
 	struct xdp_frame *xdpf;
+	bool xdp_ndo;
 	int len;
 	dma_addr_t dma_addr;
 	bool used;
@@ -467,7 +470,8 @@ int lan966x_ptp_gettime64(struct ptp_clock_info *ptp, struct timespec64 *ts);
 int lan966x_fdma_xmit(struct sk_buff *skb, __be32 *ifh, struct net_device *dev);
 int lan966x_fdma_xmit_xdpf(struct lan966x_port *port,
 			   struct xdp_frame *frame,
-			   struct page *page);
+			   struct page *page,
+			   bool dma_map);
 int lan966x_fdma_change_mtu(struct lan966x *lan966x);
 void lan966x_fdma_netdev_init(struct lan966x *lan966x, struct net_device *dev);
 void lan966x_fdma_netdev_deinit(struct lan966x *lan966x, struct net_device *dev);
@@ -565,6 +569,10 @@ int lan966x_xdp(struct net_device *dev, struct netdev_bpf *xdp);
 int lan966x_xdp_run(struct lan966x_port *port,
 		    struct page *page,
 		    u32 data_len);
+int lan966x_xdp_xmit(struct net_device *dev,
+		     int n,
+		     struct xdp_frame **frames,
+		     u32 flags);
 bool lan966x_xdp_present(struct lan966x *lan966x);
 static inline bool lan966x_xdp_port_present(struct lan966x_port *port)
 {
diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_xdp.c b/drivers/net/ethernet/microchip/lan966x/lan966x_xdp.c
index 5fd2f3b01e179..9f363316115ae 100644
--- a/drivers/net/ethernet/microchip/lan966x/lan966x_xdp.c
+++ b/drivers/net/ethernet/microchip/lan966x/lan966x_xdp.c
@@ -50,6 +50,30 @@ int lan966x_xdp(struct net_device *dev, struct netdev_bpf *xdp)
 	}
 }
 
+int lan966x_xdp_xmit(struct net_device *dev,
+		     int n,
+		     struct xdp_frame **frames,
+		     u32 flags)
+{
+	struct lan966x_port *port = netdev_priv(dev);
+	int i, nxmit = 0;
+
+	for (i = 0; i < n; ++i) {
+		struct xdp_frame *xdpf = frames[i];
+		int err;
+
+		err = lan966x_fdma_xmit_xdpf(port, xdpf,
+					     virt_to_head_page(xdpf->data),
+					     true);
+		if (err)
+			break;
+
+		nxmit++;
+	}
+
+	return nxmit;
+}
+
 int lan966x_xdp_run(struct lan966x_port *port, struct page *page, u32 data_len)
 {
 	struct bpf_prog *xdp_prog = port->xdp_prog;
@@ -72,8 +96,13 @@ int lan966x_xdp_run(struct lan966x_port *port, struct page *page, u32 data_len)
 		if (!xdpf)
 			return FDMA_DROP;
 
-		return lan966x_fdma_xmit_xdpf(port, xdpf, page) ?
+		return lan966x_fdma_xmit_xdpf(port, xdpf, page, false) ?
 		       FDMA_DROP : FDMA_TX;
+	case XDP_REDIRECT:
+		if (xdp_do_redirect(port->dev, &xdp, xdp_prog))
+			return FDMA_DROP;
+
+		return FDMA_REDIRECT;
 	default:
 		bpf_warn_invalid_xdp_action(port->dev, xdp_prog, act);
 		fallthrough;
-- 
2.38.0