[PATCH devicetree] arm64: dts: ls1028a-rdb: add more ethernet aliases

[PATCH devicetree] arm64: dts: ls1028a-rdb: add more ethernet aliases

[Vladimir Oltean]

Commit "arm64: dts: ls1028a: enable swp5 and eno3 for all boards" which
Shawn declared as applied, but for which I can't find a sha1sum, has
enabled a new Ethernet port on the LS1028A-RDB (&enetc_port3), but
U-Boot, which passes a MAC address to Linux' device tree through the
/aliases node, fails to do this for this newly enabled port.

Fix that by adding more ethernet aliases in the only
backwards-compatible way possible: at the end of the current list.

And since it is possible to very easily convert either swp4 or swp5 to
DSA user ports now (which have a MAC address of their own), using these
U-Boot commands:

=> fdt addr $fdt_addr_r
=> fdt rm /soc/pcie@1f0000000/ethernet-switch@0,5/ports/port@4 ethernet

it would be good if those DSA user ports (swp4, swp5) gained a valid MAC
address from U-Boot as well. In order for that to work properly,
provision two more ethernet aliases for &mscc_felix_port{4,5} as well.

The resulting ordering is slightly unusual, but to me looks more natural
than eno0, eno2, swp0, swp1, swp2, swp3, eno3, swp4, swp5.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
 arch/arm64/boot/dts/freescale/fsl-ls1028a-rdb.dts | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/arm64/boot/dts/freescale/fsl-ls1028a-rdb.dts b/arch/arm64/boot/dts/freescale/fsl-ls1028a-rdb.dts
index e33725c60169..ecd2c1ea177f 100644
--- a/arch/arm64/boot/dts/freescale/fsl-ls1028a-rdb.dts
+++ b/arch/arm64/boot/dts/freescale/fsl-ls1028a-rdb.dts
@@ -29,6 +29,9 @@ aliases {
 		ethernet3 = &mscc_felix_port1;
 		ethernet4 = &mscc_felix_port2;
 		ethernet5 = &mscc_felix_port3;
+		ethernet6 = &mscc_felix_port4;
+		ethernet7 = &mscc_felix_port5;
+		ethernet8 = &enetc_port3;
 	};
 
 	chosen {
-- 
2.34.1


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Re: [PATCH devicetree] arm64: dts: ls1028a-rdb: add more ethernet aliases

[Michael Walle]

Am 2022-09-05 23:24, schrieb Vladimir Oltean:
> Commit "arm64: dts: ls1028a: enable swp5 and eno3 for all boards" which
> Shawn declared as applied, but for which I can't find a sha1sum, has
> enabled a new Ethernet port on the LS1028A-RDB (&enetc_port3), but
> U-Boot, which passes a MAC address to Linux' device tree through the
> /aliases node, fails to do this for this newly enabled port.
> 
> Fix that by adding more ethernet aliases in the only
> backwards-compatible way possible: at the end of the current list.
> 
> And since it is possible to very easily convert either swp4 or swp5 to
> DSA user ports now (which have a MAC address of their own), using these
> U-Boot commands:
> 
> => fdt addr $fdt_addr_r
> => fdt rm /soc/pcie@1f0000000/ethernet-switch@0,5/ports/port@4 ethernet
> 
> it would be good if those DSA user ports (swp4, swp5) gained a valid 
> MAC
> address from U-Boot as well. In order for that to work properly,
> provision two more ethernet aliases for &mscc_felix_port{4,5} as well.

First, let me say, I'm fine with this patch. But I'm not sure,
how many MAC addresses are actually reserved on your
RDB/QDS boards? I guess, they being evaluation boards you
don't care? ;)
On the Kontron sl28 boards we reserve just 8 and that is
already a lot for a board with max 6 out facing ports. 4 of
these ports used to be a switch, so in theory it should work
with 3 MAC addresses, right? Or even just 2 if there is no
need to terminate any traffic on the switch interfaces.

Anyway, do we really need so many addresses? What are the
configurations here? For what is the address of the
internal ports used?

Let's say we are in the "port extender mode" and use the
second internal port as an actual switch port, that would
then be:
2x external enetc
1x internal enetc
4x external switch ports in port extender mode

Which makes 7 addresses. The internal enetc port doesn't
really make sense in a port extender mode, because there
is no switching going on. So uhm, 6 addresses are the
maximum?

This is the MAC address distribution for now on the
sl28 boards:
https://lore.kernel.org/linux-devicetree/20220901221857.2600340-19-michael@walle.cc/

Please tell me if I'm missing something here.

-michael

> The resulting ordering is slightly unusual, but to me looks more 
> natural
> than eno0, eno2, swp0, swp1, swp2, swp3, eno3, swp4, swp5.
> 
> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>

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Re: [PATCH devicetree] arm64: dts: ls1028a-rdb: add more ethernet aliases

[Vladimir Oltean]

On Tue, Sep 06, 2022 at 12:17:29AM +0200, Michael Walle wrote:
> First, let me say, I'm fine with this patch. But I'm not sure,
> how many MAC addresses are actually reserved on your
> RDB/QDS boards?

AFAIK, the Reference Design Boards are sold with an unprogrammed I2C
EEPROM, but with a sticker containing 5 MAC addresses on the bottom of
the board. It doesn't have a clear correspondence between MAC addresses
and their intended use, although I suspect that one MAC address is
intended for each RJ45 port (although that isn't how I use them).

For the QIXIS Development Boards, I have no clue, it's probably even
nonsensical to talk about MAC address reservations since there is just
one onboard Ethernet port (RGMII) and the rest is routed via SERDES to
PCIe slots, to pluggable riser cards, from which Linux/U-Boot don't bother
too much to read back any info, even though I can't exclude something
like an EEPROM may be available on those cards too. In any case, I think
QDS boards don't leave the lab, so it doesn't matter too much.

The way I use the MAC addresses from the sticker of my RDBs, on a day to
day basis, is:

ethaddr (eno0) - #1
eth1addr (eno2) - #2
eth2addr (swp0) - #2
eth3addr (swp1) - #2
eth4addr (swp2) - #2
eth5addr (swp3) - #2

And now I'm adding these new env variables:

eth6addr (swp4) - #2
eth7addr (swp5) - #2
eth8addr (eno3) - #3

So I still have 2 more unique MAC addresses to burn through.

> I guess, they being evaluation boards you don't care? ;)

I do care a bit, but not that much.

> On the Kontron sl28 boards we reserve just 8 and that is
> already a lot for a board with max 6 out facing ports. 4 of
> these ports used to be a switch, so in theory it should work

/used/ to be a switch? What happened to them? Details? Or you mean
"4 ports are used as a switch"?

> with 3 MAC addresses, right?

Which 3 MAC addresses would those be? Not sure I'm following. enetc #0,
enetc #1, enetc #2? That could work, multiple DSA user ports can share
the same MAC address (inherited from the DSA master or not) and things
would work just fine unless you connect them to each other.

> Or even just 2 if there is no need to terminate any traffic on the
> switch interfaces.

And here, which 2? enetc #0 and enetc #1?

> Anyway, do we really need so many addresses?

idk, who's "we" and what does "need" mean? (serious questions)

I'm not sure I can give you any answer to this question. As an engineer
working with the kernel, I need to roll the LS1028A Ethernet around on
all its sides. The Linux RDB/QDS support will inevitably reflect what we
need to test. Everybody else will have a fixed configuration, and the
user reviews will vary from 'internet works! 5 stars!' to 'internet
doesn't work! 1 star!'.

To offer that quality of service for all front-facing ports, you don't
need much. I know of a 12 port industrial switch that entered production
with 1 MAC address, the "termination" address. It's fine, when it's
marketed as a switch, people come to expect that and don't wonder too much.

> What are the configurations here? For what is the address of the
> internal ports used?

By internal ports you mean swp4/swp5, or eno2/eno3? If eno2/eno3, then a
configuration where having MAC addresses on these interfaces is useful
to me is running some of the kselftests on the LS1028A-RDB, which does
not have enough external enetc ports for 2 loopback pairs, so I do
this, thereby having 1 external loopback through a cable, and 1 internal
loopback in the SoC:

./psfp.sh eno0 swp0 swp4 eno2
https://github.com/torvalds/linux/blob/master/tools/testing/selftests/drivers/net/ocelot/psfp.sh

Speaking of kselftests, it actually doesn't matter that much what the
MAC addresses *are*, since we don't enter any network, just loop back
traffic. In fact we have an environment variable STABLE_MAC_ADDRS, which
when set, configures the ports to use some predetermined MAC addresses.

There are other configurations where it is useful for eno2 to see DSA
untagged traffic. These are downstream 802.1CB (where this hardware can
offload redundant streams in the forwarding plane, but not in the
termination plane, so we use eno2 as forwarding plane, for termination),
DPDK on eno2 (which mainline Linux doesn't care about), and vfio-pci +
QEMU, where DSA switch control still belongs to the Linux host, but the
guest has 'internet'.

> Let's say we are in the "port extender mode" and use the
> second internal port as an actual switch port, that would
> then be:
> 2x external enetc
> 1x internal enetc
> 4x external switch ports in port extender mode
> 
> Which makes 7 addresses. The internal enetc port doesn't
> really make sense in a port extender mode, because there
> is no switching going on.

It can make sense. You can run ptp4l -i eno2, and ptp4l -i swp4, as
separate processes, and you can get high quality synchronization between
/dev/ptp0 (enetc) and /dev/ptp1 (felix) over internal Ethernet (there
isn't any other mechanism in the SoC to keep them in sync if that is
needed for some use case like a boundary_clock_jbod between eno0 + eno1
+ swp0-swp3).

> So uhm, 6 addresses are the maximum?

No, the maximum is given by the number of ports, PFs and VFs. But that's
a high number. It's the theoretical maximum. Then there's the practical
maximum, which is given by what kind of embedded system is built with it.
I think that the more general-purpose the system is, the more garden
variety the networking use cases will be. I also think it would be very
absurd for everybody to reserve a number of MAC addresses equal to the
number of possibilities in which the LS1028A can expose IP termination
points, if they're likely to never need them.

> This is the MAC address distribution for now on the
> sl28 boards:
> https://lore.kernel.org/linux-devicetree/20220901221857.2600340-19-michael@walle.cc/
> 
> Please tell me if I'm missing something here.

My 2 cents, if you don't need anything special like in-SoC PTP, 802.1CB,
virtualization, and don't habitually connect ports of the same ports to
each other or do some other sorts of redundant networking without VLANs,
then there isn't too much wrong with one MAC address per RJ45 port, but
best discuss with those who are actually marketing the devices.
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Re: [PATCH devicetree] arm64: dts: ls1028a-rdb: add more ethernet aliases

[Michael Walle]

Am 2022-09-06 01:54, schrieb Vladimir Oltean:
> On Tue, Sep 06, 2022 at 12:17:29AM +0200, Michael Walle wrote:
>> First, let me say, I'm fine with this patch. But I'm not sure,
>> how many MAC addresses are actually reserved on your
>> RDB/QDS boards?
> 
> AFAIK, the Reference Design Boards are sold with an unprogrammed I2C
> EEPROM, but with a sticker containing 5 MAC addresses on the bottom of
> the board. It doesn't have a clear correspondence between MAC addresses
> and their intended use, although I suspect that one MAC address is
> intended for each RJ45 port (although that isn't how I use them).
> 
> For the QIXIS Development Boards, I have no clue, it's probably even
> nonsensical to talk about MAC address reservations since there is just
> one onboard Ethernet port (RGMII) and the rest is routed via SERDES to
> PCIe slots, to pluggable riser cards, from which Linux/U-Boot don't 
> bother
> too much to read back any info, even though I can't exclude something
> like an EEPROM may be available on those cards too. In any case, I 
> think
> QDS boards don't leave the lab, so it doesn't matter too much.
> 
> The way I use the MAC addresses from the sticker of my RDBs, on a day 
> to
> day basis, is:
> 
> ethaddr (eno0) - #1
> eth1addr (eno2) - #2
> eth2addr (swp0) - #2
> eth3addr (swp1) - #2
> eth4addr (swp2) - #2
> eth5addr (swp3) - #2

Ah, I never thought of handing out the same MAC address.

> And now I'm adding these new env variables:
> 
> eth6addr (swp4) - #2
> eth7addr (swp5) - #2
> eth8addr (eno3) - #3
> 
> So I still have 2 more unique MAC addresses to burn through.
> 
>> I guess, they being evaluation boards you don't care? ;)
> 
> I do care a bit, but not that much.
> 
>> On the Kontron sl28 boards we reserve just 8 and that is
>> already a lot for a board with max 6 out facing ports. 4 of
>> these ports used to be a switch, so in theory it should work
> 
> /used/ to be a switch? What happened to them? Details? Or you mean
> "4 ports are used as a switch"?

I shouldn't probably write mails right before going to sleep.
Yes it should read "the 4 ports (swp0..swp3) are usually configured
to as a switch."

>> with 3 MAC addresses, right?
> 
> Which 3 MAC addresses would those be? Not sure I'm following. enetc #0,
> enetc #1, enetc #2? That could work, multiple DSA user ports can share
> the same MAC address (inherited from the DSA master or not) and things
> would work just fine unless you connect them to each other.

enetc #0, #1 and swp0. As you mentioned, swp1..3 should inherit the
address from swp0 then if swp0 is added as the first device, right?

So why would enetc#2 (or #3) need a non-random mac address? I must
be missing something here.

>> Or even just 2 if there is no need to terminate any traffic on the
>> switch interfaces.
> 
> And here, which 2? enetc #0 and enetc #1?

Yes. The switch would just be a dumb ethernet switch.

>> Anyway, do we really need so many addresses?
> 
> idk, who's "we" and what does "need" mean? (serious questions)

We as in the users of the ls1028a SoC. And as I said, I thought
of *unique* MAC addresses.

> I'm not sure I can give you any answer to this question. As an engineer
> working with the kernel, I need to roll the LS1028A Ethernet around on
> all its sides. The Linux RDB/QDS support will inevitably reflect what 
> we
> need to test. Everybody else will have a fixed configuration, and the
> user reviews will vary from 'internet works! 5 stars!' to 'internet
> doesn't work! 1 star!'.
> 
> To offer that quality of service for all front-facing ports, you don't
> need much. I know of a 12 port industrial switch that entered 
> production
> with 1 MAC address, the "termination" address. It's fine, when it's
> marketed as a switch, people come to expect that and don't wonder too 
> much.
> 
>> What are the configurations here? For what is the address of the
>> internal ports used?
> 
> By internal ports you mean swp4/swp5, or eno2/eno3?

eno2/eno3.

> If eno2/eno3, then a
> configuration where having MAC addresses on these interfaces is useful
> to me is running some of the kselftests on the LS1028A-RDB, which does
> not have enough external enetc ports for 2 loopback pairs, so I do
> this, thereby having 1 external loopback through a cable, and 1 
> internal
> loopback in the SoC:
> 
> ./psfp.sh eno0 swp0 swp4 eno2
> https://github.com/torvalds/linux/blob/master/tools/testing/selftests/drivers/net/ocelot/psfp.sh
> 
> Speaking of kselftests, it actually doesn't matter that much what the
> MAC addresses *are*, since we don't enter any network, just loop back
> traffic. In fact we have an environment variable STABLE_MAC_ADDRS, 
> which
> when set, configures the ports to use some predetermined MAC addresses.
> 
> There are other configurations where it is useful for eno2 to see DSA
> untagged traffic. These are downstream 802.1CB (where this hardware can
> offload redundant streams in the forwarding plane, but not in the
> termination plane, so we use eno2 as forwarding plane, for 
> termination),

I'm not that familiar with 802.1CB. Is this MAC address visible outside
of the switch or can it be a random one?

> DPDK on eno2 (which mainline Linux doesn't care about), and vfio-pci +
> QEMU, where DSA switch control still belongs to the Linux host, but the
> guest has 'internet'.

For me, all of that is kind of a trade off. If you want to use
virtual interfaces, you might need to borrow a MAC address from
one of the switch ports (where you have 3 unique addresses left
if you combine all 4 ports to one bridge).

>> Let's say we are in the "port extender mode" and use the
>> second internal port as an actual switch port, that would
>> then be:
>> 2x external enetc
>> 1x internal enetc
>> 4x external switch ports in port extender mode
>> 
>> Which makes 7 addresses. The internal enetc port doesn't
>> really make sense in a port extender mode, because there
>> is no switching going on.
> 
> It can make sense. You can run ptp4l -i eno2, and ptp4l -i swp4, as
> separate processes, and you can get high quality synchronization 
> between
> /dev/ptp0 (enetc) and /dev/ptp1 (felix) over internal Ethernet (there
> isn't any other mechanism in the SoC to keep them in sync if that is
> needed for some use case like a boundary_clock_jbod between eno0 + eno1
> + swp0-swp3).

Ok, could make sense.

>> So uhm, 6 addresses are the maximum?
> 
> No, the maximum is given by the number of ports, PFs and VFs. But 
> that's
> a high number. It's the theoretical maximum. Then there's the practical
> maximum, which is given by what kind of embedded system is built with 
> it.
> I think that the more general-purpose the system is, the more garden
> variety the networking use cases will be. I also think it would be very
> absurd for everybody to reserve a number of MAC addresses equal to the
> number of possibilities in which the LS1028A can expose IP termination
> points, if they're likely to never need them.

I think we are on the same track here. I was ignoring any VFs for now.
So I guess, what I'm still missing here is why enet#2 and enet#3 (or
even swp4 and swp5) would need a non-random MAC address. Except from
your example above. Considering the usecase where swp0..3 is one bridge
with eno2 and eno3 being the CPU ports. Then I'd only need a unique
MAC address for eno0, eno1 and swp0, correct?

-michael

>> This is the MAC address distribution for now on the
>> sl28 boards:
>> https://lore.kernel.org/linux-devicetree/20220901221857.2600340-19-michael@walle.cc/
>> 
>> Please tell me if I'm missing something here.
> 
> My 2 cents, if you don't need anything special like in-SoC PTP, 
> 802.1CB,
> virtualization, and don't habitually connect ports of the same ports to
> each other or do some other sorts of redundant networking without 
> VLANs,
> then there isn't too much wrong with one MAC address per RJ45 port, but
> best discuss with those who are actually marketing the devices.


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Re: [PATCH devicetree] arm64: dts: ls1028a-rdb: add more ethernet aliases

[Vladimir Oltean]

On Tue, Sep 06, 2022 at 10:10:50AM +0200, Michael Walle wrote:
> > > with 3 MAC addresses, right?
> > 
> > Which 3 MAC addresses would those be? Not sure I'm following. enetc #0,
> > enetc #1, enetc #2? That could work, multiple DSA user ports can share
> > the same MAC address (inherited from the DSA master or not) and things
> > would work just fine unless you connect them to each other.
> 
> enetc #0, #1 and swp0. As you mentioned, swp1..3 should inherit the
> address from swp0 then if swp0 is added as the first device, right?
> 
> So why would enetc#2 (or #3) need a non-random mac address? I must
> be missing something here.

I didn't say that swp1..3 inherit the MAC address from swp0. I said that
the DSA user ports can inherit the MAC address from the DSA master (eno2
or eno3). See dsa_slave_create():

	if (!is_zero_ether_addr(port->mac)) // device tree
		eth_hw_addr_set(slave_dev, port->mac);
	else
		eth_hw_addr_inherit(slave_dev, master);

The DSA user ports (swp0-swp3) can also share the same MAC address which
is not inherited from the DSA master (eno2), but this can only be
achieved through static configuration (such as manually setting the same
mac-address in the device tree).

> > If eno2/eno3, then a
> > configuration where having MAC addresses on these interfaces is useful
> > to me is running some of the kselftests on the LS1028A-RDB, which does
> > not have enough external enetc ports for 2 loopback pairs, so I do
> > this, thereby having 1 external loopback through a cable, and 1 internal
> > loopback in the SoC:
> > 
> > ./psfp.sh eno0 swp0 swp4 eno2
> > https://github.com/torvalds/linux/blob/master/tools/testing/selftests/drivers/net/ocelot/psfp.sh
> > 
> > Speaking of kselftests, it actually doesn't matter that much what the
> > MAC addresses *are*, since we don't enter any network, just loop back
> > traffic. In fact we have an environment variable STABLE_MAC_ADDRS, which
> > when set, configures the ports to use some predetermined MAC addresses.
> > 
> > There are other configurations where it is useful for eno2 to see DSA
> > untagged traffic. These are downstream 802.1CB (where this hardware can
> > offload redundant streams in the forwarding plane, but not in the
> > termination plane, so we use eno2 as forwarding plane, for termination),
> 
> I'm not that familiar with 802.1CB. Is this MAC address visible outside
> of the switch or can it be a random one?

The MAC address of eno2 is visible outside the switch, onto the network.
Take this 802.1CB ring network for example:
https://github.com/vladimiroltean/isochron/blob/master/frer/8021cb.sh

Every board has 2 redundant ports in the ring, and every board can ping
every other board through the redundant ring, through an IP termination
point (eno2). Except that the switch does not support inserting/stripping
802.1CB redundancy headers for locally terminated traffic, or splitting/
eliminating duplicate streams for locally terminated traffic.

So we configure the switch to consider the internal swp4 as a user port,
and effectively set it up for the forwarding plane, in a bridge with
swp0 and swp1. It's now as if each eno2 used for termination is
connected to a switch that's physically separate from the LS1028A, which
handles the redundant forwarding. Except it's not physically separate,
it's part of the same SoC, and its DSA master is eno3. All in all, it
requires a bit of a split brain syndrome to work with it. This is in
fact one of the key things blocking 802.1CB upstreaming for us, as a
side note - we don't have a very good proposal for modeling a generic
software data path for this.

You can see more details here if you care enough:
https://patchwork.kernel.org/project/netdevbpf/patch/20210928114451.24956-1-xiaoliang.yang_1@nxp.com/

> > DPDK on eno2 (which mainline Linux doesn't care about), and vfio-pci +
> > QEMU, where DSA switch control still belongs to the Linux host, but the
> > guest has 'internet'.
> 
> For me, all of that is kind of a trade off. If you want to use
> virtual interfaces, you might need to borrow a MAC address from
> one of the switch ports (where you have 3 unique addresses left
> if you combine all 4 ports to one bridge).

I didn't say virtual interfaces in this case, I said vfio-pci which is a
way to do PCI direct assignment to a guest OS, which sees the whole
0000:00:00.2 PF corresponding to eno2.

By the way, the internal enetc ports eno2 and eno3 don't have VFs since
SR-IOV is a bit of a complicated topic when DSA-tagged traffic is
expected (you don't want a guest OS to see DSA tags in packets, it
doesn't know what to do with them). But this is one of the main reasons
we have 2 internal ports btw. You configure eno3 as a DSA master, you
leave swp4 as a user port, so now eno2 sees DSA untagged traffic and you
can do direct assignment to whomever.

> > > So uhm, 6 addresses are the maximum?
> > 
> > No, the maximum is given by the number of ports, PFs and VFs. But that's
> > a high number. It's the theoretical maximum. Then there's the practical
> > maximum, which is given by what kind of embedded system is built with
> > it.
> > I think that the more general-purpose the system is, the more garden
> > variety the networking use cases will be. I also think it would be very
> > absurd for everybody to reserve a number of MAC addresses equal to the
> > number of possibilities in which the LS1028A can expose IP termination
> > points, if they're likely to never need them.
> 
> I think we are on the same track here. I was ignoring any VFs for now.
> So I guess, what I'm still missing here is why enet#2 and enet#3 (or
> even swp4 and swp5) would need a non-random MAC address. Except from
> your example above. Considering the usecase where swp0..3 is one bridge
> with eno2 and eno3 being the CPU ports. Then I'd only need a unique
> MAC address for eno0, eno1 and swp0, correct?

Don't say "unique MAC address for swp0", since swp0's MAC address is not
unique, you probably mean to say "a MAC address which will be shared by
swp0-swp3".

I think I've answered why eno2/eno3 could need a stable MAC address -
for the case when they aren't used as DSA masters (through the switch
termination plane) but as interfaces unaware of the switch connected to
them (through the switch forwarding plane).
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Re: [PATCH devicetree] arm64: dts: ls1028a-rdb: add more ethernet aliases

[Michael Walle]

Am 2022-09-06 12:05, schrieb Vladimir Oltean:
> On Tue, Sep 06, 2022 at 10:10:50AM +0200, Michael Walle wrote:
>> > > with 3 MAC addresses, right?
>> >
>> > Which 3 MAC addresses would those be? Not sure I'm following. enetc #0,
>> > enetc #1, enetc #2? That could work, multiple DSA user ports can share
>> > the same MAC address (inherited from the DSA master or not) and things
>> > would work just fine unless you connect them to each other.
>> 
>> enetc #0, #1 and swp0. As you mentioned, swp1..3 should inherit the
>> address from swp0 then if swp0 is added as the first device, right?
>> 
>> So why would enetc#2 (or #3) need a non-random mac address? I must
>> be missing something here.
> 
> I didn't say that swp1..3 inherit the MAC address from swp0. I said 
> that
> the DSA user ports can inherit the MAC address from the DSA master 
> (eno2
> or eno3). See dsa_slave_create():
> 
> 	if (!is_zero_ether_addr(port->mac)) // device tree
> 		eth_hw_addr_set(slave_dev, port->mac);
> 	else
> 		eth_hw_addr_inherit(slave_dev, master);
> 
> The DSA user ports (swp0-swp3) can also share the same MAC address 
> which
> is not inherited from the DSA master (eno2), but this can only be
> achieved through static configuration (such as manually setting the 
> same
> mac-address in the device tree).

Right. I need to jog my memory on the whole briding stuff again. Sorry,
I mixed that up with the bridge using the lowest MAC as its id. I.e.
it looked like br0 inherited the address from the interface which
was added to it first.

>> > If eno2/eno3, then a
>> > configuration where having MAC addresses on these interfaces is useful
>> > to me is running some of the kselftests on the LS1028A-RDB, which does
>> > not have enough external enetc ports for 2 loopback pairs, so I do
>> > this, thereby having 1 external loopback through a cable, and 1 internal
>> > loopback in the SoC:
>> >
>> > ./psfp.sh eno0 swp0 swp4 eno2
>> > https://github.com/torvalds/linux/blob/master/tools/testing/selftests/drivers/net/ocelot/psfp.sh
>> >
>> > Speaking of kselftests, it actually doesn't matter that much what the
>> > MAC addresses *are*, since we don't enter any network, just loop back
>> > traffic. In fact we have an environment variable STABLE_MAC_ADDRS, which
>> > when set, configures the ports to use some predetermined MAC addresses.
>> >
>> > There are other configurations where it is useful for eno2 to see DSA
>> > untagged traffic. These are downstream 802.1CB (where this hardware can
>> > offload redundant streams in the forwarding plane, but not in the
>> > termination plane, so we use eno2 as forwarding plane, for termination),
>> 
>> I'm not that familiar with 802.1CB. Is this MAC address visible 
>> outside
>> of the switch or can it be a random one?
> 
> The MAC address of eno2 is visible outside the switch, onto the 
> network.
> Take this 802.1CB ring network for example:
> https://github.com/vladimiroltean/isochron/blob/master/frer/8021cb.sh
> 
> Every board has 2 redundant ports in the ring, and every board can ping
> every other board through the redundant ring, through an IP termination
> point (eno2). Except that the switch does not support 
> inserting/stripping
> 802.1CB redundancy headers for locally terminated traffic, or 
> splitting/
> eliminating duplicate streams for locally terminated traffic.
> 
> So we configure the switch to consider the internal swp4 as a user 
> port,
> and effectively set it up for the forwarding plane, in a bridge with
> swp0 and swp1. It's now as if each eno2 used for termination is
> connected to a switch that's physically separate from the LS1028A, 
> which
> handles the redundant forwarding. Except it's not physically separate,
> it's part of the same SoC, and its DSA master is eno3. All in all, it
> requires a bit of a split brain syndrome to work with it. This is in
> fact one of the key things blocking 802.1CB upstreaming for us, as a
> side note - we don't have a very good proposal for modeling a generic
> software data path for this.
> 
> You can see more details here if you care enough:
> https://patchwork.kernel.org/project/netdevbpf/patch/20210928114451.24956-1-xiaoliang.yang_1@nxp.com/
> 
>> > DPDK on eno2 (which mainline Linux doesn't care about), and vfio-pci +
>> > QEMU, where DSA switch control still belongs to the Linux host, but the
>> > guest has 'internet'.
>> 
>> For me, all of that is kind of a trade off. If you want to use
>> virtual interfaces, you might need to borrow a MAC address from
>> one of the switch ports (where you have 3 unique addresses left
>> if you combine all 4 ports to one bridge).
> 
> I didn't say virtual interfaces in this case, I said vfio-pci which is 
> a
> way to do PCI direct assignment to a guest OS, which sees the whole
> 0000:00:00.2 PF corresponding to eno2.

Yes of course. I need to find a good compromise for the MAC assignments.
And running virtualization on our board might be a use case, but I
don't know how common that one is. So for now, I'm ignoring it.

> By the way, the internal enetc ports eno2 and eno3 don't have VFs since
> SR-IOV is a bit of a complicated topic when DSA-tagged traffic is
> expected (you don't want a guest OS to see DSA tags in packets, it
> doesn't know what to do with them). But this is one of the main reasons
> we have 2 internal ports btw. You configure eno3 as a DSA master, you
> leave swp4 as a user port, so now eno2 sees DSA untagged traffic and 
> you
> can do direct assignment to whomever.
> 
>> > > So uhm, 6 addresses are the maximum?
>> >
>> > No, the maximum is given by the number of ports, PFs and VFs. But that's
>> > a high number. It's the theoretical maximum. Then there's the practical
>> > maximum, which is given by what kind of embedded system is built with
>> > it.
>> > I think that the more general-purpose the system is, the more garden
>> > variety the networking use cases will be. I also think it would be very
>> > absurd for everybody to reserve a number of MAC addresses equal to the
>> > number of possibilities in which the LS1028A can expose IP termination
>> > points, if they're likely to never need them.
>> 
>> I think we are on the same track here. I was ignoring any VFs for now.
>> So I guess, what I'm still missing here is why enet#2 and enet#3 (or
>> even swp4 and swp5) would need a non-random MAC address. Except from
>> your example above. Considering the usecase where swp0..3 is one 
>> bridge
>> with eno2 and eno3 being the CPU ports. Then I'd only need a unique
>> MAC address for eno0, eno1 and swp0, correct?
> 
> Don't say "unique MAC address for swp0", since swp0's MAC address is 
> not
> unique, you probably mean to say "a MAC address which will be shared by
> swp0-swp3".

That I actually don't understand. I have the following addresses after
booting:

# ip link
..
4: gbe0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP 
group default qlen 1000
     link/ether 00:a0:a5:5c:6b:62 brd ff:ff:ff:ff:ff:ff
     inet 172.16.1.2/24 scope global gbe0
        valid_lft forever preferred_lft forever
     inet6 fe80::2a0:a5ff:fe5c:6b62/64 scope link
        valid_lft forever preferred_lft forever
5: gbe1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group 
default qlen 1000
     link/ether 00:a0:a5:5c:6b:63 brd ff:ff:ff:ff:ff:ff
6: eno2: <BROADCAST,MULTICAST> mtu 1504 qdisc noop state DOWN group 
default qlen 1000
     link/ether 8e:6c:20:8a:ab:52 brd ff:ff:ff:ff:ff:ff
7: eno3: <BROADCAST,MULTICAST> mtu 1504 qdisc noop state DOWN group 
default qlen 1000
     link/ether c6:fd:b1:88:3c:36 brd ff:ff:ff:ff:ff:ff
8: swp0@eno2: <BROADCAST,MULTICAST,M-DOWN> mtu 1500 qdisc noop state 
DOWN group default qlen 1000
     link/ether 00:a0:a5:5c:6b:66 brd ff:ff:ff:ff:ff:ff
9: swp1@eno2: <BROADCAST,MULTICAST,M-DOWN> mtu 1500 qdisc noop state 
DOWN group default qlen 1000
     link/ether 00:a0:a5:5c:6b:67 brd ff:ff:ff:ff:ff:ff
10: swp2@eno2: <BROADCAST,MULTICAST,M-DOWN> mtu 1500 qdisc noop state 
DOWN group default qlen 1000
     link/ether 00:a0:a5:5c:6b:68 brd ff:ff:ff:ff:ff:ff
11: swp3@eno2: <BROADCAST,MULTICAST,M-DOWN> mtu 1500 qdisc noop state 
DOWN group default qlen 1000
     link/ether 00:a0:a5:5c:6b:69 brd ff:ff:ff:ff:ff:ff

gbe0 is eno0 and gbe1 is eno1. So in my case they are unique.

When adding all the ports to a bridge, the bridge gets the lowest MAC.

# ip link add name br0 type bridge
# ip link set swp0 master br0
# ip link set swp1 master br0
# ip link set swp2 master br0
# ip link set swp3 master br0

12: br0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode 
DEFAULT group default qlen 1000
     link/ether 00:a0:a5:5c:6b:66 brd ff:ff:ff:ff:ff:ff

Is that what you mean with "a MAC address which will be shared by
swp0-swp3"?

> I think I've answered why eno2/eno3 could need a stable MAC address -
> for the case when they aren't used as DSA masters (through the switch
> termination plane) but as interfaces unaware of the switch connected to
> them (through the switch forwarding plane).

Yes thanks for the explanation!

-michael

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Re: [PATCH devicetree] arm64: dts: ls1028a-rdb: add more ethernet aliases

[Vladimir Oltean]

On Wed, Sep 07, 2022 at 10:56:37AM +0200, Michael Walle wrote:
> > > I think we are on the same track here. I was ignoring any VFs for now.
> > > So I guess, what I'm still missing here is why enet#2 and enet#3 (or
> > > even swp4 and swp5) would need a non-random MAC address. Except from
> > > your example above. Considering the usecase where swp0..3 is one bridge
> > > with eno2 and eno3 being the CPU ports. Then I'd only need a unique
> > > MAC address for eno0, eno1 and swp0, correct?
> > 
> > Don't say "unique MAC address for swp0", since swp0's MAC address is not
> > unique, you probably mean to say "a MAC address which will be shared by
> > swp0-swp3".
> 
> That I actually don't understand. I have the following addresses after
> booting:
> 
> # ip link
> ..
> 4: gbe0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group
> default qlen 1000
>     link/ether 00:a0:a5:5c:6b:62 brd ff:ff:ff:ff:ff:ff
>     inet 172.16.1.2/24 scope global gbe0
>        valid_lft forever preferred_lft forever
>     inet6 fe80::2a0:a5ff:fe5c:6b62/64 scope link
>        valid_lft forever preferred_lft forever
> 5: gbe1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default
> qlen 1000
>     link/ether 00:a0:a5:5c:6b:63 brd ff:ff:ff:ff:ff:ff
> 6: eno2: <BROADCAST,MULTICAST> mtu 1504 qdisc noop state DOWN group default
> qlen 1000
>     link/ether 8e:6c:20:8a:ab:52 brd ff:ff:ff:ff:ff:ff
> 7: eno3: <BROADCAST,MULTICAST> mtu 1504 qdisc noop state DOWN group default
> qlen 1000
>     link/ether c6:fd:b1:88:3c:36 brd ff:ff:ff:ff:ff:ff
> 8: swp0@eno2: <BROADCAST,MULTICAST,M-DOWN> mtu 1500 qdisc noop state DOWN
> group default qlen 1000
>     link/ether 00:a0:a5:5c:6b:66 brd ff:ff:ff:ff:ff:ff
> 9: swp1@eno2: <BROADCAST,MULTICAST,M-DOWN> mtu 1500 qdisc noop state DOWN
> group default qlen 1000
>     link/ether 00:a0:a5:5c:6b:67 brd ff:ff:ff:ff:ff:ff
> 10: swp2@eno2: <BROADCAST,MULTICAST,M-DOWN> mtu 1500 qdisc noop state DOWN
> group default qlen 1000
>     link/ether 00:a0:a5:5c:6b:68 brd ff:ff:ff:ff:ff:ff
> 11: swp3@eno2: <BROADCAST,MULTICAST,M-DOWN> mtu 1500 qdisc noop state DOWN
> group default qlen 1000
>     link/ether 00:a0:a5:5c:6b:69 brd ff:ff:ff:ff:ff:ff
> 
> gbe0 is eno0 and gbe1 is eno1. So in my case they are unique.
> 
> When adding all the ports to a bridge, the bridge gets the lowest MAC.
> 
> # ip link add name br0 type bridge
> # ip link set swp0 master br0
> # ip link set swp1 master br0
> # ip link set swp2 master br0
> # ip link set swp3 master br0
> 
> 12: br0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT
> group default qlen 1000
>     link/ether 00:a0:a5:5c:6b:66 brd ff:ff:ff:ff:ff:ff
> 
> Is that what you mean with "a MAC address which will be shared by
> swp0-swp3"?

No, what I'm trying is only to reformulate what you've said, "Then I'd
only need a unique MAC address for eno0, eno1 and swp0". My understanding
of what you mean by "unique address for swp0" is that the addresses for
swp1-swp3 don't matter (hence they can be set to the same address as swp0)
since there will be a bridge that serves as the IP termination point,
with its own MAC address, inherited from the first bridge port, swp0.
But this makes it improper to call it a "unique address for swp0".
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Re: [PATCH devicetree] arm64: dts: ls1028a-rdb: add more ethernet aliases

[Shawn Guo]

On Tue, Sep 06, 2022 at 12:24:58AM +0300, Vladimir Oltean wrote:
> Commit "arm64: dts: ls1028a: enable swp5 and eno3 for all boards" which
> Shawn declared as applied, but for which I can't find a sha1sum, has
> enabled a new Ethernet port on the LS1028A-RDB (&enetc_port3), but
> U-Boot, which passes a MAC address to Linux' device tree through the
> /aliases node, fails to do this for this newly enabled port.
> 
> Fix that by adding more ethernet aliases in the only
> backwards-compatible way possible: at the end of the current list.
> 
> And since it is possible to very easily convert either swp4 or swp5 to
> DSA user ports now (which have a MAC address of their own), using these
> U-Boot commands:
> 
> => fdt addr $fdt_addr_r
> => fdt rm /soc/pcie@1f0000000/ethernet-switch@0,5/ports/port@4 ethernet
> 
> it would be good if those DSA user ports (swp4, swp5) gained a valid MAC
> address from U-Boot as well. In order for that to work properly,
> provision two more ethernet aliases for &mscc_felix_port{4,5} as well.
> 
> The resulting ordering is slightly unusual, but to me looks more natural
> than eno0, eno2, swp0, swp1, swp2, swp3, eno3, swp4, swp5.
> 
> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>

Applied, thanks!

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