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From:   Horatiu Vultur <horatiu.vultur@microchip.com>
To:     <linux-kernel@vger.kernel.org>, <netdev@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>,
        <linux@armlinux.org.uk>, <UNGLinuxDriver@microchip.com>,
        Horatiu Vultur <horatiu.vultur@microchip.com>
Subject: [PATCH net-next 4/5] net: lan966x: Add basic XDP support
Date:   Wed, 19 Oct 2022 15:50:07 +0200
Message-ID: <20221019135008.3281743-5-horatiu.vultur@microchip.com>
In-Reply-To: <20221019135008.3281743-1-horatiu.vultur@microchip.com>
References: <20221019135008.3281743-1-horatiu.vultur@microchip.com>
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Introduce basic XDP support to lan966x driver. Currently the driver
supports only the actions XDP_PASS, XDP_DROP and XDP_ABORTED.
Currently the driver doesn't support xdp programs if any of the ports
have the MTU bigger than a page size.

Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
---
 .../net/ethernet/microchip/lan966x/Makefile   |   3 +-
 .../ethernet/microchip/lan966x/lan966x_fdma.c |  14 ++-
 .../ethernet/microchip/lan966x/lan966x_main.c |   5 +
 .../ethernet/microchip/lan966x/lan966x_main.h |  14 +++
 .../ethernet/microchip/lan966x/lan966x_xdp.c  | 100 ++++++++++++++++++
 5 files changed, 134 insertions(+), 2 deletions(-)
 create mode 100644 drivers/net/ethernet/microchip/lan966x/lan966x_xdp.c

diff --git a/drivers/net/ethernet/microchip/lan966x/Makefile b/drivers/net/ethernet/microchip/lan966x/Makefile
index 962f7c5f9e7dd..251a7d561d633 100644
--- a/drivers/net/ethernet/microchip/lan966x/Makefile
+++ b/drivers/net/ethernet/microchip/lan966x/Makefile
@@ -11,4 +11,5 @@ lan966x-switch-objs  := lan966x_main.o lan966x_phylink.o lan966x_port.o \
 			lan966x_ptp.o lan966x_fdma.o lan966x_lag.o \
 			lan966x_tc.o lan966x_mqprio.o lan966x_taprio.o \
 			lan966x_tbf.o lan966x_cbs.o lan966x_ets.o \
-			lan966x_tc_matchall.o lan966x_police.o lan966x_mirror.o
+			lan966x_tc_matchall.o lan966x_police.o lan966x_mirror.o \
+			lan966x_xdp.o
diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c b/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c
index 6b6baf6a3d1ee..4e8f7e47c5536 100644
--- a/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c
+++ b/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c
@@ -422,6 +422,7 @@ static bool lan966x_fdma_rx_more_frames(struct lan966x_rx *rx)
 static int lan966x_fdma_rx_check_frame(struct lan966x_rx *rx, u64 *src_port)
 {
 	struct lan966x *lan966x = rx->lan966x;
+	struct lan966x_port *port;
 	struct lan966x_db *db;
 	struct page *page;
 
@@ -439,7 +440,11 @@ static int lan966x_fdma_rx_check_frame(struct lan966x_rx *rx, u64 *src_port)
 	if (WARN_ON(*src_port >= lan966x->num_phys_ports))
 		return FDMA_RX_ERROR;
 
-	return FDMA_RX_OK;
+	port = lan966x->ports[*src_port];
+	if (!lan966x_xdp_port_present(port))
+		return FDMA_RX_OK;
+
+	return lan966x_xdp_run(port, page, FDMA_DCB_STATUS_BLOCKL(db->status));
 }
 
 static struct sk_buff *lan966x_fdma_rx_get_frame(struct lan966x_rx *rx,
@@ -518,6 +523,10 @@ static int lan966x_fdma_napi_poll(struct napi_struct *napi, int weight)
 		switch (err) {
 		case FDMA_RX_OK:
 			break;
+		case FDMA_RX_DROP:
+			lan966x_fdma_rx_free_page(rx);
+			lan966x_fdma_rx_advance_dcb(rx);
+			continue;
 		case FDMA_RX_ERROR:
 			lan966x_fdma_rx_free_page(rx);
 			lan966x_fdma_rx_advance_dcb(rx);
@@ -776,6 +785,9 @@ int lan966x_fdma_change_mtu(struct lan966x *lan966x)
 	    lan966x->rx.page_order)
 		return 0;
 
+	if (lan966x_xdp_present(lan966x) && max_mtu >= PAGE_SIZE)
+		return -EINVAL;
+
 	/* Disable the CPU port */
 	lan_rmw(QSYS_SW_PORT_MODE_PORT_ENA_SET(0),
 		QSYS_SW_PORT_MODE_PORT_ENA,
diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_main.c b/drivers/net/ethernet/microchip/lan966x/lan966x_main.c
index 4fa8c07039d9f..2e48caaadd59c 100644
--- a/drivers/net/ethernet/microchip/lan966x/lan966x_main.c
+++ b/drivers/net/ethernet/microchip/lan966x/lan966x_main.c
@@ -487,6 +487,7 @@ static const struct net_device_ops lan966x_port_netdev_ops = {
 	.ndo_get_port_parent_id		= lan966x_port_get_parent_id,
 	.ndo_eth_ioctl			= lan966x_port_ioctl,
 	.ndo_setup_tc			= lan966x_tc_setup,
+	.ndo_bpf			= lan966x_xdp,
 };
 
 bool lan966x_netdevice_check(const struct net_device *dev)
@@ -713,6 +714,7 @@ static void lan966x_cleanup_ports(struct lan966x *lan966x)
 		if (port->dev)
 			unregister_netdev(port->dev);
 
+		lan966x_xdp_port_deinit(port);
 		if (lan966x->fdma && lan966x->fdma_ndev == port->dev)
 			lan966x_fdma_netdev_deinit(lan966x, port->dev);
 
@@ -1155,6 +1157,9 @@ static int lan966x_probe(struct platform_device *pdev)
 		lan966x->ports[p]->serdes = serdes;
 
 		lan966x_port_init(lan966x->ports[p]);
+		err = lan966x_xdp_port_init(lan966x->ports[p]);
+		if (err)
+			goto cleanup_ports;
 	}
 
 	lan966x_mdb_init(lan966x);
diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_main.h b/drivers/net/ethernet/microchip/lan966x/lan966x_main.h
index 608e2cb81b095..e635e529df0d4 100644
--- a/drivers/net/ethernet/microchip/lan966x/lan966x_main.h
+++ b/drivers/net/ethernet/microchip/lan966x/lan966x_main.h
@@ -100,10 +100,12 @@ enum macaccess_entry_type {
 
 /* FDMA rx error codes for checking if the frame is valid
  * FDMA_RX_OK, frame is valid and can be used
+ * FDMA_RX_DROP, frame is dropped, but continue to get more frames
  * FDMA_RX_ERROR, something went wrong, stop getting more frames
  */
 enum lan966x_fdma_rx_error {
 	FDMA_RX_OK = 0,
+	FDMA_RX_DROP,
 	FDMA_RX_ERROR,
 };
 
@@ -327,6 +329,9 @@ struct lan966x_port {
 	enum netdev_lag_hash hash_type;
 
 	struct lan966x_port_tc tc;
+
+	struct bpf_prog *xdp_prog;
+	struct xdp_rxq_info xdp_rxq;
 };
 
 extern const struct phylink_mac_ops lan966x_phylink_mac_ops;
@@ -536,6 +541,15 @@ void lan966x_mirror_port_stats(struct lan966x_port *port,
 			       struct flow_stats *stats,
 			       bool ingress);
 
+int lan966x_xdp_port_init(struct lan966x_port *port);
+void lan966x_xdp_port_deinit(struct lan966x_port *port);
+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);
+bool lan966x_xdp_present(struct lan966x *lan966x);
+bool lan966x_xdp_port_present(struct lan966x_port *port);
+
 static inline void __iomem *lan_addr(void __iomem *base[],
 				     int id, int tinst, int tcnt,
 				     int gbase, int ginst,
diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_xdp.c b/drivers/net/ethernet/microchip/lan966x/lan966x_xdp.c
new file mode 100644
index 0000000000000..b65bf648c543b
--- /dev/null
+++ b/drivers/net/ethernet/microchip/lan966x/lan966x_xdp.c
@@ -0,0 +1,100 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+#include <linux/bpf.h>
+#include <linux/bpf_trace.h>
+#include <linux/filter.h>
+
+#include "lan966x_main.h"
+
+static int lan966x_xdp_setup(struct net_device *dev, struct netdev_bpf *xdp)
+{
+	struct lan966x_port *port = netdev_priv(dev);
+	struct lan966x *lan966x = port->lan966x;
+	struct bpf_prog *old_prog;
+
+	if (!lan966x->fdma) {
+		NL_SET_ERR_MSG_MOD(xdp->extack,
+				   "Allow to set xdp only when using fdma");
+		return -EOPNOTSUPP;
+	}
+
+	if (lan966x_get_max_mtu(lan966x) >= PAGE_SIZE) {
+		NL_SET_ERR_MSG_MOD(xdp->extack,
+				   "Jumbo frames not supported on XDP");
+		return -EOPNOTSUPP;
+	}
+
+	old_prog = xchg(&port->xdp_prog, xdp->prog);
+	if (old_prog)
+		bpf_prog_put(old_prog);
+
+	return 0;
+}
+
+int lan966x_xdp(struct net_device *dev, struct netdev_bpf *xdp)
+{
+	switch (xdp->command) {
+	case XDP_SETUP_PROG:
+		return lan966x_xdp_setup(dev, xdp);
+	default:
+		return -EINVAL;
+	}
+}
+
+int lan966x_xdp_run(struct lan966x_port *port, struct page *page, u32 data_len)
+{
+	struct bpf_prog *xdp_prog = port->xdp_prog;
+	struct xdp_buff xdp;
+	u32 act;
+
+	xdp_init_buff(&xdp, PAGE_SIZE, &port->xdp_rxq);
+	xdp_prepare_buff(&xdp, page_address(page), IFH_LEN_BYTES,
+			 data_len - IFH_LEN_BYTES, false);
+	act = bpf_prog_run_xdp(xdp_prog, &xdp);
+	switch (act) {
+	case XDP_PASS:
+		return FDMA_RX_OK;
+	default:
+		bpf_warn_invalid_xdp_action(port->dev, xdp_prog, act);
+		fallthrough;
+	case XDP_ABORTED:
+		trace_xdp_exception(port->dev, xdp_prog, act);
+		fallthrough;
+	case XDP_DROP:
+		return FDMA_RX_DROP;
+	}
+}
+
+bool lan966x_xdp_port_present(struct lan966x_port *port)
+{
+	return !!port->xdp_prog;
+}
+
+bool lan966x_xdp_present(struct lan966x *lan966x)
+{
+	int p;
+
+	for (p = 0; p < lan966x->num_phys_ports; ++p) {
+		if (!lan966x->ports[p])
+			continue;
+
+		if (lan966x_xdp_port_present(lan966x->ports[p]))
+			return true;
+	}
+
+	return false;
+}
+
+int lan966x_xdp_port_init(struct lan966x_port *port)
+{
+	struct lan966x *lan966x = port->lan966x;
+
+	return xdp_rxq_info_reg(&port->xdp_rxq, port->dev, 0,
+				lan966x->napi.napi_id);
+}
+
+void lan966x_xdp_port_deinit(struct lan966x_port *port)
+{
+	if (xdp_rxq_info_is_reg(&port->xdp_rxq))
+		xdp_rxq_info_unreg(&port->xdp_rxq);
+}
-- 
2.38.0