Re: [patch net-next RFC 07/12] dsa: implement ndo_swdev_get_id

Jiri Pirko [off-list ref] writes:

Thu, Aug 21, 2014 at 06:56:13PM CEST, f.fainelli-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org wrote:

quoted

2014-08-21 9:19 GMT-07:00 Jiri Pirko [off-list ref]:

quoted

Signed-off-by: Jiri Pirko <redacted>
---
 net/dsa/Kconfig |  2 +-
 net/dsa/slave.c | 16 ++++++++++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/net/dsa/Kconfig b/net/dsa/Kconfig
index f5eede1..66c445a 100644
--- a/net/dsa/Kconfig
+++ b/net/dsa/Kconfig

@@ -1,6 +1,6 @@
 config HAVE_NET_DSA
        def_bool y
-       depends on NETDEVICES && !S390
+       depends on NETDEVICES && NET_SWITCHDEV && !S390

 # Drivers must select NET_DSA and the appropriate tagging format

diff --git a/net/dsa/slave.c b/net/dsa/slave.c
index 45a1e34..e069ba3 100644
--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c

@@ -171,6 +171,19 @@ static int dsa_slave_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
        return -EOPNOTSUPP;
 }

+static int dsa_slave_swdev_get_id(struct net_device *dev,
+                                 struct netdev_phys_item_id *psid)
+{
+       struct dsa_slave_priv *p = netdev_priv(dev);
+       struct dsa_switch *ds = p->parent;
+       u64 tmp = (u64) ds;
+
+       /* TODO: add more sophisticated id generation */
+       memcpy(&psid->id, &tmp, sizeof(tmp));
+       psid->id_len = sizeof(tmp);

There is already an unique id generated, which is the index in the
switch tree, and which is stored in struct dsa_switch, so this could
probably be simplified to:

psid->id = ds->index

That index is 0..n if I understand that correctly. That is not enough.
The point is to have unique id for every chip in the system. If we would
have 0,1,2... the collision is very likely.

I am just kibitzing but ethernet switches capable of speaking stp
require a mac address per port.  So if you want a unique id I would
pick one of your mac addresses, which should be uniuqe.

I can understand low end devices where sophisticated things will never
happen fudging on the mac address requirements but by the time you care
I expect you have a mac address.

Eric