Re: [PATCH 0/4] bcma: support SHIM-attached big-endian SoC backplanes (BCM6362)

[Arend van Spriel <arend.vanspriel@broadcom.com>]

On 29/05/2026 02:05, Alessio Ferri wrote:
> Some BMIPS xDSL SoCs (BCM6362) integrate a Broadcom 802.11 backplane that is reachable
> through bcma but differs from the BCM47xx SoCs host_soc was written for:
> the AXI backplane is big-endian on a big-endian CPU, and the cores bcma must gate
> (ChipCommon, the 802.11 core, the SHIM core) expose no per-core DMP wrappers — clock
> and reset live in a small SoC-level SHIM Control register instead.
> 
> Rather than describe these quirks as DT properties on the bcma node, the SoC-specific
> configuration is delivered to host_soc via platform_data from a parent bridge driver. The
> bcma DT node stays a plain "brcm,bus-axi" and all the 6362-specific knowledge lives in the
> bridge driver. The standard brcm,bus-axi path is unchanged.
> 
> The series is:
>    1/4  bcma: support driver specific quirks from soc pdata
>    2/4  bcma: allow SHIM-style mini-EROM wrapper-less cores in scan
>    3/4  dt-bindings: bus: add brcm,bcm6362-wlan
>    4/4  bus: add BCM6362 on-chip WLAN SHIM bridge driver
> 
> Patches 1-2 touch drivers/bcma (wireless tree); patch 3 is a new drivers/bus driver; patch 4 is
> the binding. The patches are sent together to keep the whole context intact.
> 
> The original Broadcom driver materialized a fake PCI device, i don't think that would be allowed
> in the kernel.
> 
> Tested on a D-Link DSL-3580L (BCM6362, d11 corerev 22, N-PHY):
> - SHIM brings the backplane up,
> - bcma enumerates ChipCommon + the 802.11 core,
> - b43 binds.
> 
> b43 patches are necessary for the last point, but those has
> already been sent in linux-wireless.

Hi Alessio,

This patch series ended up on my patchwork plate for the linux-wireless 
project. However, there is not much wifi specifics going on in these 
patches that I can comment on. So this probably needs the attention of 
Rafał and Florian who are already listed. Added linux-mips mailing list 
here. Hopefully it showed up on the review list in other subsystems.

Regarding this hardware I suspect the rest of the SoC used the Broadcom 
UBUS interconnect so the SHIM bridge would actually be a UBUS-AXI bridge 
of sorts which hooks up the WLAN cores.

Regards,
Arend

> Assisted-by: Claude:claude-4.8-opus
> Signed-off-by: Alessio Ferri <alessio.ferri@mythread.it>
> 
> ---
> Alessio Ferri (4):
>        bcma: support driver specific quirks from soc pdata
>        bcma: allow SHIM-style mini-EROM wrapper-less cores in scan
>        dt-bindings: bus: add brcm,bcm6362-wlan
>        bus: add BCM6362 on-chip WLAN SHIM bridge driver