[PATCH v2] arm64: dts: broadcom: bcm2712: rpi-5: Add ethernet0 alias

[PATCH v2] arm64: dts: broadcom: bcm2712: rpi-5: Add ethernet0 alias

[Laurent Pinchart]

The RP1 ethernet controller DT node contains a local-mac-address
property to pass the MAC address from the boot loader to the kernel. The
boot loader does not fill the MAC address as the ethernet0 alias is
missing. Add it.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---
Changes since v1:

- Moved the alias to bcm2712-rpi-5-b.dts
---
 arch/arm64/boot/dts/broadcom/bcm2712-rpi-5-b.dts | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/arm64/boot/dts/broadcom/bcm2712-rpi-5-b.dts b/arch/arm64/boot/dts/broadcom/bcm2712-rpi-5-b.dts
index 09a849dd09b1..3e0319fdb93f 100644
--- a/arch/arm64/boot/dts/broadcom/bcm2712-rpi-5-b.dts
+++ b/arch/arm64/boot/dts/broadcom/bcm2712-rpi-5-b.dts
@@ -18,6 +18,12 @@
 
 #include "bcm2712-rpi-5-b-ovl-rp1.dts"
 
+/ {
+	aliases {
+		ethernet0 = &rp1_eth;
+	};
+};
+
 &pcie2 {
 	#include "rp1-nexus.dtsi"
 };

base-commit: dcb6fa37fd7bc9c3d2b066329b0d27dedf8becaa
-- 
Regards,

Laurent Pinchart

Re: [PATCH v2] arm64: dts: broadcom: bcm2712: rpi-5: Add ethernet0 alias

[Andrew Lunn]

On Sun, Nov 02, 2025 at 01:14:42PM +0200, Laurent Pinchart wrote:
> The RP1 ethernet controller DT node contains a local-mac-address
> property to pass the MAC address from the boot loader to the kernel. The
> boot loader does not fill the MAC address as the ethernet0 alias is
> missing. Add it.
> 
> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> ---

Should this have a Fixes: tag?

What MAC address does it currently get?  Random?

	Andrew

Re: [PATCH v2] arm64: dts: broadcom: bcm2712: rpi-5: Add ethernet0 alias

[Laurent Pinchart]

On Sun, Nov 02, 2025 at 04:35:30PM +0100, Andrew Lunn wrote:
> On Sun, Nov 02, 2025 at 01:14:42PM +0200, Laurent Pinchart wrote:
> > The RP1 ethernet controller DT node contains a local-mac-address
> > property to pass the MAC address from the boot loader to the kernel. The
> > boot loader does not fill the MAC address as the ethernet0 alias is
> > missing. Add it.
> > 
> > Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > ---
> 
> Should this have a Fixes: tag?

I can add

Fixes: 43456fdfc014 ("arm64: dts: broadcom: Enable RP1 ethernet for Raspberry Pi 5")

(or maybe Florian can when picking up this patch, if a v3 is not
needed).

> What MAC address does it currently get?  Random?

The local-mac-address property is not currently filled by the boot
loader, so it's all 0's. The kernel then assigns a random MAC address.

-- 
Regards,

Laurent Pinchart

Re: [PATCH v2] arm64: dts: broadcom: bcm2712: rpi-5: Add ethernet0 alias

[Florian Fainelli]

On 11/2/2025 7:48 AM, Laurent Pinchart wrote:
> On Sun, Nov 02, 2025 at 04:35:30PM +0100, Andrew Lunn wrote:
>> On Sun, Nov 02, 2025 at 01:14:42PM +0200, Laurent Pinchart wrote:
>>> The RP1 ethernet controller DT node contains a local-mac-address
>>> property to pass the MAC address from the boot loader to the kernel. The
>>> boot loader does not fill the MAC address as the ethernet0 alias is
>>> missing. Add it.
>>>
>>> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
>>> ---
>>
>> Should this have a Fixes: tag?
> 
> I can add
> 
> Fixes: 43456fdfc014 ("arm64: dts: broadcom: Enable RP1 ethernet for Raspberry Pi 5")
> 
> (or maybe Florian can when picking up this patch, if a v3 is not
> needed).

Yes I will add the tag while applying, thanks!

> 
>> What MAC address does it currently get?  Random?
> 
> The local-mac-address property is not currently filled by the boot
> loader, so it's all 0's. The kernel then assigns a random MAC address.
> 

Definitively a fix.
-- 
Florian

Re: [PATCH v2] arm64: dts: broadcom: bcm2712: rpi-5: Add ethernet0 alias

[Andrea della Porta]

Hi Laurent,

On 13:14 Sun 02 Nov     , Laurent Pinchart wrote:
> The RP1 ethernet controller DT node contains a local-mac-address
> property to pass the MAC address from the boot loader to the kernel. The
> boot loader does not fill the MAC address as the ethernet0 alias is
> missing. Add it.
> 
> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> ---
> Changes since v1:
> 
> - Moved the alias to bcm2712-rpi-5-b.dts
> ---
>  arch/arm64/boot/dts/broadcom/bcm2712-rpi-5-b.dts | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/broadcom/bcm2712-rpi-5-b.dts b/arch/arm64/boot/dts/broadcom/bcm2712-rpi-5-b.dts
> index 09a849dd09b1..3e0319fdb93f 100644
> --- a/arch/arm64/boot/dts/broadcom/bcm2712-rpi-5-b.dts
> +++ b/arch/arm64/boot/dts/broadcom/bcm2712-rpi-5-b.dts
> @@ -18,6 +18,12 @@
>  
>  #include "bcm2712-rpi-5-b-ovl-rp1.dts"
>  
> +/ {
> +	aliases {
> +		ethernet0 = &rp1_eth;
> +	};
> +};
> +
>  &pcie2 {
>  	#include "rp1-nexus.dtsi"
>  };

LGTM,
Reviewed-by: Andrea della Porta <andrea.porta@suse.com>

Many thanks,
Andrea

> 
> base-commit: dcb6fa37fd7bc9c3d2b066329b0d27dedf8becaa
> -- 
> Regards,
> 
> Laurent Pinchart
> 

Re: [PATCH v2] arm64: dts: broadcom: bcm2712: rpi-5: Add ethernet0 alias

[Florian Fainelli]

From: Florian Fainelli <f.fainelli@gmail.com>

On Sun,  2 Nov 2025 13:14:42 +0200, Laurent Pinchart <laurent.pinchart@ideasonboard.com> wrote:
> The RP1 ethernet controller DT node contains a local-mac-address
> property to pass the MAC address from the boot loader to the kernel. The
> boot loader does not fill the MAC address as the ethernet0 alias is
> missing. Add it.
> 
> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> ---

Applied to https://github.com/Broadcom/stblinux/commits/devicetree-arm64/next, thanks!
--
Florian

Re: [PATCH v2] arm64: dts: broadcom: bcm2712: rpi-5: Add ethernet0 alias

[Rob Herring]

On Sun, Nov 2, 2025 at 5:15 AM Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
>
> The RP1 ethernet controller DT node contains a local-mac-address
> property to pass the MAC address from the boot loader to the kernel. The
> boot loader does not fill the MAC address as the ethernet0 alias is
> missing. Add it.

My change here[1] is going to effectively revert this. The RP1 stuff
needs to either be an overlay or not. We don't need both ways.
/aliases don't work for overlays. I suppose that could be added as a
fixup when applying. The kernel also assumes aliases are not dynamic
and uses indexes which aren't present, so even if it did work there
would still be problems. OTOH, if the bootloader might use the
ethernet controller, then why would this ever be an overlay in the
first place?

Turns out digging into RP1 stuff, it is a mess and needs reworking[2].

Right now, I just want the warning gone so I don't get further complaints[3].

Rob

[1] https://lore.kernel.org/all/20251117211503.728354-2-robh@kernel.org/
[2] https://lore.kernel.org/all/CAL_JsqJUzB71QdMcxJtNZ7raoPcK+SfTh7EVzGmk=syo8xLKQw@mail.gmail.com/
[3] https://lore.kernel.org/all/CAHk-=wi+ge-gtCg+iLd6dgjisGchjtsKY8AXG9tXGOxqVv8Fkw@mail.gmail.com/

Re: [PATCH v2] arm64: dts: broadcom: bcm2712: rpi-5: Add ethernet0 alias

[Laurent Pinchart]

Hi Rob,

On Thu, Dec 11, 2025 at 12:42:40PM -0600, Rob Herring wrote:
> On Sun, Nov 2, 2025 at 5:15 AM Laurent Pinchart wrote:
> >
> > The RP1 ethernet controller DT node contains a local-mac-address
> > property to pass the MAC address from the boot loader to the kernel. The
> > boot loader does not fill the MAC address as the ethernet0 alias is
> > missing. Add it.
> 
> My change here[1] is going to effectively revert this.

:-(

> The RP1 stuff
> needs to either be an overlay or not. We don't need both ways.
> /aliases don't work for overlays. I suppose that could be added as a
> fixup when applying. The kernel also assumes aliases are not dynamic
> and uses indexes which aren't present, so even if it did work there
> would still be problems. OTOH, if the bootloader might use the
> ethernet controller, then why would this ever be an overlay in the
> first place?
> 
> Turns out digging into RP1 stuff, it is a mess and needs reworking[2].

I don't have a strong opinion personally. As far as I understand from
https://lore.kernel.org/all/cover.1748526284.git.andrea.porta@suse.com/,
non-overlay support was added for compatibility with downstream. I don't
know why the overlay option was considered better for upstream. Andrea,
could you comment on this ?

> Right now, I just want the warning gone so I don't get further complaints[3].
> 
> Rob
> 
> [1] https://lore.kernel.org/all/20251117211503.728354-2-robh@kernel.org/
> [2] https://lore.kernel.org/all/CAL_JsqJUzB71QdMcxJtNZ7raoPcK+SfTh7EVzGmk=syo8xLKQw@mail.gmail.com/
> [3] https://lore.kernel.org/all/CAHk-=wi+ge-gtCg+iLd6dgjisGchjtsKY8AXG9tXGOxqVv8Fkw@mail.gmail.com/

-- 
Regards,

Laurent Pinchart

Re: [PATCH v2] arm64: dts: broadcom: bcm2712: rpi-5: Add ethernet0 alias

[Andrea della Porta]

Hi Laurent, Rob,

On 11:37 Fri 12 Dec     , Laurent Pinchart wrote:
> Hi Rob,
> 
> On Thu, Dec 11, 2025 at 12:42:40PM -0600, Rob Herring wrote:
> > On Sun, Nov 2, 2025 at 5:15 AM Laurent Pinchart wrote:
> > >
> > > The RP1 ethernet controller DT node contains a local-mac-address
> > > property to pass the MAC address from the boot loader to the kernel. The
> > > boot loader does not fill the MAC address as the ethernet0 alias is
> > > missing. Add it.
> > 
> > My change here[1] is going to effectively revert this.
> 
> :-(
> 
> > The RP1 stuff
> > needs to either be an overlay or not. We don't need both ways.
> > /aliases don't work for overlays. I suppose that could be added as a
> > fixup when applying. The kernel also assumes aliases are not dynamic
> > and uses indexes which aren't present, so even if it did work there
> > would still be problems. OTOH, if the bootloader might use the
> > ethernet controller, then why would this ever be an overlay in the
> > first place?
> > 
> > Turns out digging into RP1 stuff, it is a mess and needs reworking[2].

I'm currently working on it.

> 
> I don't have a strong opinion personally. As far as I understand from
> https://lore.kernel.org/all/cover.1748526284.git.andrea.porta@suse.com/,
> non-overlay support was added for compatibility with downstream. I don't
> know why the overlay option was considered better for upstream. Andrea,
> could you comment on this ?

The overlay support was initially conceived for three main reasons:

- it was mildly asked for the driver to work also on ACPI based system. It was
  not clear if the ACPI tables would also include entries for the RP1 so I
  assumeed they did not (which would be most probably the case). I'm not aware
  of any hw which complies with these scenario.

- there was a non zero (even though close to zero) chance that RP1 could be used
  on other appliances (i.e. some PCI cards), which makes teh overlay approach 
  appealing. Again, I'm not aware of any real existing hw, if ever.

- paving the way already opened by Bootlin's LAN driver seemed IMHO a good thing
  to pursue (I would say that drivers for FPGA peripherals could benefit the most
  from this approach but there could be others), so why not kicking it off with
  this driver.

Unfortunately, the overlay support is not fully working for all but the simplest
peripherals that requires referencing their nodes from the main DTB, for reasons
debated starting from this thread [1].

This is why the full DT has been provided as the default. Now that I see that the
overlay support is causing a lot of pain and concerns, I'm planning to evict it
in favor of the full DT only, overlay is not used anyway and will not be functional
until we solve all those issues which could be in a very long time, if ever feasible.

> 
> > Right now, I just want the warning gone so I don't get further complaints[3].

I'm also on this. Please provide a priority between fixing this warning (I need to
do a round of tests) and fixing the RP1 DT hierarchy (there will be changes in
both DT and driver code).

Many thanks,
Andrea

[1] - https://lore.kernel.org/all/CAMEGJJ3=W8_R0xBvm8r+Q7iExZx8xPBHEWWGAT9ngpGWDSKCaQ@mail.gmail.com/

> > 
> > Rob
> > 
> > [1] https://lore.kernel.org/all/20251117211503.728354-2-robh@kernel.org/
> > [2] https://lore.kernel.org/all/CAL_JsqJUzB71QdMcxJtNZ7raoPcK+SfTh7EVzGmk=syo8xLKQw@mail.gmail.com/
> > [3] https://lore.kernel.org/all/CAHk-=wi+ge-gtCg+iLd6dgjisGchjtsKY8AXG9tXGOxqVv8Fkw@mail.gmail.com/
> 
> -- 
> Regards,
> 
> Laurent Pinchart