[PATCH net-next v2] net: dsa: make "label" property optional for dsa2

Vivien Didelot
2017-01-08T23:16:38Z

In the new DTS bindings for DSA (dsa2), the "ethernet" and "link"
phandles are respectively mandatory and exclusive to CPU port and DSA
link device tree nodes.

Simplify dsa2.c a bit by checking the presence of such phandle instead
of checking the redundant "label" property.

Then the Linux philosophy for Ethernet switch ports is to expose them to
userspace as standard NICs by default. Thus use the standard enumerated
"eth%d" device name if no "label" property is provided for a user port.
This allows to save DTS files from subjective net device names.

Here's an example on a ZII Dev Rev B board without "label" properties:

# ip link | grep ': ' | cut -d: -f2
lo
eth0
eth1
eth2@eth1
eth3@eth1
eth4@eth1
eth5@eth1
eth6@eth1
eth7@eth1
eth8@eth1
eth9@eth1
eth10@eth1
eth11@eth1
eth12@eth1

If one wants to rename an interface, udev rules can be used as usual, as
suggested in the switchdev documentation:

# cat /etc/udev/rules.d/90-net-dsa.rules
SUBSYSTEM=="net", ACTION=="add", ENV{DEVTYPE}=="dsa", NAME="sw$attr{phys_switch_id}p$attr{phys_port_id}"

# ip link | awk '/@eth/ { split($2,a,"@"); print a[1]; }'
sw00000000p00
sw00000000p01
sw00000000p02
sw01000000p00
sw01000000p01
sw01000000p02
sw02000000p00
sw02000000p01
sw02000000p02
sw02000000p03
sw02000000p04

Until the printing of netdev_phys_item_id structures is fixed in
net/core/net-sysfs.c, an external helper can be used like this:

# cat /etc/udev/rules.d/90-net-dsa.rules
SUBSYSTEM=="net", ACTION=="add", ENV{DEVTYPE}=="dsa", PROGRAM="/lib/udev/dsanitizer $attr{phys_switch_id} $attr{phys_port_id}", NAME="$result"

# cat /lib/udev/dsanitizer
#!/bin/sh
echo $1 | sed -e 's,^0*,,' -e 's,0*$,,' | xargs printf sw%d
echo $2 | sed -e 's,^0*,,' | xargs printf p%d

# ip link | awk '/@eth/ { split($2,a,"@"); print a[1]; }'
sw0p0
sw0p1
sw0p2
sw1p0
sw1p1
sw1p2
sw2p0
sw2p1
sw2p2
sw2p3
sw2p4

Of course the current behavior is unchanged, and the optional "label"
property for user ports has precedence over the enumerated name.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Acked-by: Uwe Kleine-König <uwe@kleine-koenig.org>
---
Documentation/devicetree/bindings/net/dsa/dsa.txt | 20 ++++++++-----------
net/dsa/dsa2.c | 24 ++++-------------------
2 files changed, 12 insertions(+), 32 deletions(-)

diff --git a/Documentation/devicetree/bindings/net/dsa/dsa.txt b/Documentation/devicetree/bindings/net/dsa/dsa.txt
index a4a570fb2494..cfe8f64eca4f 100644
--- a/Documentation/devicetree/bindings/net/dsa/dsa.txt
+++ b/Documentation/devicetree/bindings/net/dsa/dsa.txt
@@ -34,13 +34,9 @@ Required properties:

Each port children node must have the following mandatory properties:
- reg : Describes the port address in the switch
-- label : Describes the label associated with this port, which
- will become the netdev name. Special labels are
- "cpu" to indicate a CPU port and "dsa" to
- indicate an uplink/downlink port between switches in
- the cluster.

-A port labelled "dsa" has the following mandatory property:
+An uplink/downlink port between switches in the cluster has the following
+mandatory property:

- link : Should be a list of phandles to other switch's DSA
port. This port is used as the outgoing port
@@ -48,12 +44,17 @@ A port labelled "dsa" has the following mandatory property:
information must be given, not just the one hop
routes to neighbouring switches.

-A port labelled "cpu" has the following mandatory property:
+A CPU port has the following mandatory property:

- ethernet : Should be a phandle to a valid Ethernet device node.
This host device is what the switch port is
connected to.

+A user port has the following optional property:
+
+- label : Describes the label associated with this port, which
+ will become the netdev name.
+
Port child nodes may also contain the following optional standardised
properties, described in binding documents:

@@ -107,7 +108,6 @@ linked into one DSA cluster.

switch0port5: port@5 {
reg = <5>;
- label = "dsa";
phy-mode = "rgmii-txid";
link = <&switch1port6
&switch2port9>;
@@ -119,7 +119,6 @@ linked into one DSA cluster.

port@6 {
reg = <6>;
- label = "cpu";
ethernet = <&fec1>;
fixed-link {
speed = <100>;
@@ -165,7 +164,6 @@ linked into one DSA cluster.

switch1port5: port@5 {
reg = <5>;
- label = "dsa";
link = <&switch2port9>;
phy-mode = "rgmii-txid";
fixed-link {
@@ -176,7 +174,6 @@ linked into one DSA cluster.

switch1port6: port@6 {
reg = <6>;
- label = "dsa";
phy-mode = "rgmii-txid";
link = <&switch0port5>;
fixed-link {
@@ -255,7 +252,6 @@ linked into one DSA cluster.

switch2port9: port@9 {
reg = <9>;
- label = "dsa";
phy-mode = "rgmii-txid";
link = <&switch1port5
&switch0port5>;
diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c
index bad119cee2a3..9526bdf2a34a 100644
--- a/net/dsa/dsa2.c
+++ b/net/dsa/dsa2.c
@@ -81,30 +81,12 @@ static void dsa_dst_del_ds(struct dsa_switch_tree *dst,

static bool dsa_port_is_dsa(struct device_node *port)
{
- const char *name;
-
- name = of_get_property(port, "label", NULL);
- if (!name)
- return false;
-
- if (!strcmp(name, "dsa"))
- return true;
-
- return false;
+ return !!of_parse_phandle(port, "link", 0);
}

static bool dsa_port_is_cpu(struct device_node *port)
{
- const char *name;
-
- name = of_get_property(port, "label", NULL);
- if (!name)
- return false;
-
- if (!strcmp(name, "cpu"))
- return true;
-
- return false;
+ return !!of_parse_phandle(port, "ethernet", 0);
}

static bool dsa_ds_find_port(struct dsa_switch *ds,
@@ -268,6 +250,8 @@ static int dsa_user_port_apply(struct device_node *port, u32 index,
int err;

name = of_get_property(port, "label", NULL);
+ if (!name)
+ name = "eth%d";

err = dsa_slave_create(ds, ds->dev, index, name);
if (err) {
--
2.11.0