[PATCH net-next v3 5/7] net: lan966x: Update dma_dir of page_pool_params

[Horatiu Vultur <horatiu.vultur@xxxxxxxxxxxxx>]

To add support for XDP_TX it is required to be able to write to the DMA
area therefore it is required that the pages will be mapped using
DMA_BIDIRECTIONAL flag.
Therefore check if there are any xdp programs on the interfaces and in
that case set DMA_BIDRECTIONAL otherwise use DMA_FROM_DEVICE.
Therefore when a new XDP program is added it is required to redo the
page_pool.

Signed-off-by: Horatiu Vultur <horatiu.vultur@xxxxxxxxxxxxx>
---
 .../ethernet/microchip/lan966x/lan966x_fdma.c | 29 ++++++++++++++----
 .../ethernet/microchip/lan966x/lan966x_main.h |  2 ++
 .../ethernet/microchip/lan966x/lan966x_xdp.c  | 30 +++++++++++++++++++
 3 files changed, 55 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c b/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c
index 483d1470c8362..f8287a6a86ed5 100644
--- a/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c
+++ b/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c
@@ -81,6 +81,9 @@ static int lan966x_fdma_rx_alloc_page_pool(struct lan966x_rx *rx)
 	struct lan966x_port *port;
 	int i;
 
+	if (lan966x_xdp_present(lan966x))
+		pp_params.dma_dir = DMA_BIDIRECTIONAL;
+
 	rx->page_pool = page_pool_create(&pp_params);
 
 	for (i = 0; i < lan966x->num_phys_ports; ++i) {
@@ -827,16 +830,11 @@ static int lan966x_fdma_get_max_frame(struct lan966x *lan966x)
 	       XDP_PACKET_HEADROOM;
 }
 
-int lan966x_fdma_change_mtu(struct lan966x *lan966x)
+static int __lan966x_fdma_reload(struct lan966x *lan966x, int max_mtu)
 {
-	int max_mtu;
 	int err;
 	u32 val;
 
-	max_mtu = lan966x_fdma_get_max_frame(lan966x);
-	if (max_mtu == lan966x->rx.max_mtu)
-		return 0;
-
 	/* Disable the CPU port */
 	lan_rmw(QSYS_SW_PORT_MODE_PORT_ENA_SET(0),
 		QSYS_SW_PORT_MODE_PORT_ENA,
@@ -862,6 +860,25 @@ int lan966x_fdma_change_mtu(struct lan966x *lan966x)
 	return err;
 }
 
+int lan966x_fdma_change_mtu(struct lan966x *lan966x)
+{
+	int max_mtu;
+
+	max_mtu = lan966x_fdma_get_max_frame(lan966x);
+	if (max_mtu == lan966x->rx.max_mtu)
+		return 0;
+
+	return __lan966x_fdma_reload(lan966x, max_mtu);
+}
+
+int lan966x_fdma_reload_page_pool(struct lan966x *lan966x)
+{
+	int max_mtu;
+
+	max_mtu = lan966x_fdma_get_max_frame(lan966x);
+	return __lan966x_fdma_reload(lan966x, max_mtu);
+}
+
 void lan966x_fdma_netdev_init(struct lan966x *lan966x, struct net_device *dev)
 {
 	if (lan966x->fdma_ndev)
diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_main.h b/drivers/net/ethernet/microchip/lan966x/lan966x_main.h
index 7bb9098496f60..7f1231b31c924 100644
--- a/drivers/net/ethernet/microchip/lan966x/lan966x_main.h
+++ b/drivers/net/ethernet/microchip/lan966x/lan966x_main.h
@@ -466,6 +466,7 @@ void lan966x_fdma_netdev_deinit(struct lan966x *lan966x, struct net_device *dev)
 int lan966x_fdma_init(struct lan966x *lan966x);
 void lan966x_fdma_deinit(struct lan966x *lan966x);
 irqreturn_t lan966x_fdma_irq_handler(int irq, void *args);
+int lan966x_fdma_reload_page_pool(struct lan966x *lan966x);
 
 int lan966x_lag_port_join(struct lan966x_port *port,
 			  struct net_device *brport_dev,
@@ -556,6 +557,7 @@ 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);
 static inline bool lan966x_xdp_port_present(struct lan966x_port *port)
 {
 	return !!port->xdp_prog;
diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_xdp.c b/drivers/net/ethernet/microchip/lan966x/lan966x_xdp.c
index 8ebde1eb6a09c..05c5a28206558 100644
--- a/drivers/net/ethernet/microchip/lan966x/lan966x_xdp.c
+++ b/drivers/net/ethernet/microchip/lan966x/lan966x_xdp.c
@@ -11,6 +11,8 @@ 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;
+	bool old_xdp, new_xdp;
+	int err;
 
 	if (!lan966x->fdma) {
 		NL_SET_ERR_MSG_MOD(xdp->extack,
@@ -18,7 +20,20 @@ static int lan966x_xdp_setup(struct net_device *dev, struct netdev_bpf *xdp)
 		return -EOPNOTSUPP;
 	}
 
+	old_xdp = lan966x_xdp_present(lan966x);
 	old_prog = xchg(&port->xdp_prog, xdp->prog);
+	new_xdp = lan966x_xdp_present(lan966x);
+
+	if (old_xdp != new_xdp)
+		goto out;
+
+	err = lan966x_fdma_reload_page_pool(lan966x);
+	if (err) {
+		xchg(&port->xdp_prog, old_prog);
+		return err;
+	}
+
+out:
 	if (old_prog)
 		bpf_prog_put(old_prog);
 
@@ -62,6 +77,21 @@ int lan966x_xdp_run(struct lan966x_port *port, struct page *page, u32 data_len)
 	}
 }
 
+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;
-- 
2.38.0