nfp: add phys_switch_id support

Add phys_switch_id support by allowing lookup of
SWITCHDEV_ATTR_ID_PORT_PARENT_ID via the nfp_repr_port_attr_get
switchdev operation.

This is visible to user-space in the phys_switch_id attribute
of a netdev.

e.g.

cd /sys/devices/pci0000:00/0000:00:01.0/0000:01:00.0
find . -name phys_switch_id | xargs grep .
./net/eth3/phys_switch_id:00154d1300bd
./net/eth4/phys_switch_id:00154d1300bd
./net/eth2/phys_switch_id:00154d1300bd
grep: ./net/eth5/phys_switch_id: Operation not supported

In the above eth2 and eth3 and representor netdevs for the first and second
physical port. eth4 is the representor for the PF. And eth5 is the PF netdev.
Signed-off-by: Simon Horman <simon.horman@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/netronome/nfp/nfp_net_common.c

@@ -64,6 +64,7 @@
 #include <linux/vmalloc.h>
 #include <linux/ktime.h>
 
+#include <net/switchdev.h>
 #include <net/vxlan.h>
 
 #include "nfpcore/nfp_nsp.h"
@@ -3703,6 +3704,8 @@ static void nfp_net_netdev_init(struct nfp_net *nn)
 	netdev->netdev_ops = &nfp_net_netdev_ops;
 	netdev->watchdog_timeo = msecs_to_jiffies(5 * 1000);
 
+	SWITCHDEV_SET_OPS(netdev, &nfp_port_switchdev_ops);
+
 	/* MTU range: 68 - hw-specific max */
 	netdev->min_mtu = ETH_MIN_MTU;
 	netdev->max_mtu = nn->max_mtu;

drivers/net/ethernet/netronome/nfp/nfp_net_repr.c

@@ -35,6 +35,7 @@
 #include <linux/io-64-nonatomic-hi-lo.h>
 #include <linux/lockdep.h>
 #include <net/dst_metadata.h>
+#include <net/switchdev.h>
 
 #include "nfpcore/nfp_cpp.h"
 #include "nfpcore/nfp_nsp.h"
@@ -299,6 +300,7 @@ int nfp_repr_init(struct nfp_app *app, struct net_device *netdev,
 	repr->dst->u.port_info.lower_dev = pf_netdev;
 
 	netdev->netdev_ops = &nfp_repr_netdev_ops;
+	SWITCHDEV_SET_OPS(netdev, &nfp_port_switchdev_ops);
 
 	err = register_netdev(netdev);
 	if (err)

drivers/net/ethernet/netronome/nfp/nfp_port.c

@@ -32,6 +32,7 @@
  */
 
 #include <linux/lockdep.h>
+#include <net/switchdev.h>
 
 #include "nfpcore/nfp_cpp.h"
 #include "nfpcore/nfp_nsp.h"
@@ -59,6 +60,34 @@ struct nfp_port *nfp_port_from_netdev(struct net_device *netdev)
 	return NULL;
 }
 
+static int
+nfp_port_attr_get(struct net_device *netdev, struct switchdev_attr *attr)
+{
+	struct nfp_port *port;
+
+	port = nfp_port_from_netdev(netdev);
+	if (!port)
+		return -EOPNOTSUPP;
+
+	switch (attr->id) {
+	case SWITCHDEV_ATTR_ID_PORT_PARENT_ID: {
+		const u8 *serial;
+		/* N.B: attr->u.ppid.id is binary data */
+		attr->u.ppid.id_len = nfp_cpp_serial(port->app->cpp, &serial);
+		memcpy(&attr->u.ppid.id, serial, attr->u.ppid.id_len);
+		break;
+	}
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+const struct switchdev_ops nfp_port_switchdev_ops = {
+	.switchdev_port_attr_get	= nfp_port_attr_get,
+};
+
 struct nfp_port *
 nfp_port_from_id(struct nfp_pf *pf, enum nfp_port_type type, unsigned int id)
 {

drivers/net/ethernet/netronome/nfp/nfp_port.h

@@ -106,6 +106,8 @@ struct nfp_port {
 	struct list_head port_list;
 };
 
+extern const struct switchdev_ops nfp_port_switchdev_ops;
+
 struct nfp_port *nfp_port_from_netdev(struct net_device *netdev);
 struct nfp_port *
 nfp_port_from_id(struct nfp_pf *pf, enum nfp_port_type type, unsigned int id);