[PATCH net-next 3/7] netdevsim: Simulate get hardware address of a PCI port

[Parav Pandit <parav@nvidia.com>]

Allow users to get hardware address for the PCI port.

Below example creates one devlink port, queries a port and its hardware
address.

Example of a PCI SF port which supports a port function hw_addr set:
Create a device with ID=10 and one physical port.
$ echo "10 1" > /sys/bus/netdevsim/new_device

Add PCI PF port:
$ devlink port add netdevsim/netdevsim10 flavour pcipf pfnum 2
netdevsim/netdevsim10/1: type eth netdev eth1 flavour pcipf controller 0 pfnum 2 external false splittable false
  function:
    hw_addr 00:00:00:00:00:00

$ devlink port add netdevsim/netdevsim10 flavour pcisf pfnum 2
netdevsim/netdevsim10/2: type eth netdev eth2 flavour pcisf controller 0 pfnum 2 sfnum 0 splittable false
  function:
    hw_addr 00:00:00:00:00:00

Show devlink ports:
$ devlink port show
netdevsim/netdevsim10/0: type eth netdev eth0 flavour physical port 1 splittable false
netdevsim/netdevsim10/1: type eth netdev eth1 flavour pcipf controller 0 pfnum 2 external false splittable false
  function:
    hw_addr 00:00:00:00:00:00
netdevsim/netdevsim10/2: type eth netdev eth2 flavour pcisf controller 0 pfnum 2 sfnum 0 splittable false
  function:
    hw_addr 00:00:00:00:00:00

Show the port and function attributes in JSON format:
$ devlink port show netdevsim/netdevsim10/2 -jp
{
    "port": {
        "netdevsim/netdevsim10/2": {
            "type": "eth",
            "netdev": "eth2",
            "flavour": "pcisf",
            "controller": 0,
            "pfnum": 2,
            "sfnum": 0,
            "splittable": false,
            "function": {
                "hw_addr": "00:00:00:00:00:00"
            }
        }
    }
}

Signed-off-by: Parav Pandit <parav@nvidia.com>
---
 drivers/net/netdevsim/dev.c           |  1 +
 drivers/net/netdevsim/netdevsim.h     |  4 ++++
 drivers/net/netdevsim/port_function.c | 30 +++++++++++++++++++++++++++
 3 files changed, 35 insertions(+)

diff --git a/drivers/net/netdevsim/dev.c b/drivers/net/netdevsim/dev.c
index 806e387918fe..6046906d6b85 100644
--- a/drivers/net/netdevsim/dev.c
+++ b/drivers/net/netdevsim/dev.c
@@ -907,6 +907,7 @@ static const struct devlink_ops nsim_dev_devlink_ops = {
 	.trap_policer_counter_get = nsim_dev_devlink_trap_policer_counter_get,
 	.port_new = nsim_dev_devlink_port_new,
 	.port_del = nsim_dev_devlink_port_del,
+	.port_function_hw_addr_get = nsim_dev_port_fn_hw_addr_get,
 };
 
 #define NSIM_DEV_MAX_MACS_DEFAULT 32
diff --git a/drivers/net/netdevsim/netdevsim.h b/drivers/net/netdevsim/netdevsim.h
index efa7c08d842a..e910c3cf480d 100644
--- a/drivers/net/netdevsim/netdevsim.h
+++ b/drivers/net/netdevsim/netdevsim.h
@@ -320,3 +320,7 @@ int nsim_dev_devlink_port_new(struct devlink *devlink,
 			      unsigned int *new_port_index);
 int nsim_dev_devlink_port_del(struct devlink *devlink, unsigned int port_index,
 			      struct netlink_ext_ack *extack);
+int nsim_dev_port_fn_hw_addr_get(struct devlink *devlink,
+				 struct devlink_port *port,
+				 u8 *hw_addr, int *hw_addr_len,
+				 struct netlink_ext_ack *extack);
diff --git a/drivers/net/netdevsim/port_function.c b/drivers/net/netdevsim/port_function.c
index a2f62a609e9b..4031598e2076 100644
--- a/drivers/net/netdevsim/port_function.c
+++ b/drivers/net/netdevsim/port_function.c
@@ -16,6 +16,7 @@ struct nsim_port_fn {
 	int refcount; /* Counts how many sf ports are bound attached to this pf port. */
 	u32 sfnum;
 	u16 pfnum;
+	u8 hw_addr[ETH_ALEN];
 };
 
 static struct devlink_port *
@@ -431,3 +432,32 @@ void nsim_dev_port_fn_disable(struct nsim_dev *nsim_dev)
 		nsim_devlink_port_fn_free(nsim_dev, port);
 	}
 }
+
+static struct nsim_port_fn *
+nsim_dev_to_port_fn(struct nsim_dev *nsim_dev, struct devlink_port *dl_port,
+		    struct netlink_ext_ack *extack)
+{
+	if (nsim_dev_port_index_internal(nsim_dev, dl_port->index)) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "Port index doesn't belong to user created port");
+		return ERR_PTR(-EOPNOTSUPP);
+	}
+	return container_of(dl_port, struct nsim_port_fn, dl_port);
+}
+
+int nsim_dev_port_fn_hw_addr_get(struct devlink *devlink,
+				 struct devlink_port *dl_port,
+				 u8 *hw_addr, int *hw_addr_len,
+				 struct netlink_ext_ack *extack)
+{
+	struct nsim_dev *nsim_dev = devlink_priv(devlink);
+	struct nsim_port_fn *port;
+
+	port = nsim_dev_to_port_fn(nsim_dev, dl_port, extack);
+	if (IS_ERR(port))
+		return PTR_ERR(port);
+
+	memcpy(hw_addr, port->hw_addr, ETH_ALEN);
+	*hw_addr_len = ETH_ALEN;
+	return 0;
+}
-- 
2.26.2