Re: [PATCH v2 2/4] brcmfmac: Support 89459 pcie

From: Hector Martin
Date: Mon Jan 02 2023 - 09:01:25 EST


On 02/01/2023 22.58, Arend van Spriel wrote:
> On 1/2/2023 10:45 AM, Aditya Garg wrote:
>> Hi Hector
>>
>>>
>>> Is the CYW89459 just a rebrand of the BCM4355, or just a subset? If it
>>> is a rebrand, it's okay if we call our Apple firmware
>>> brcmfmac89459-pcie* (note that we use per-board firmware names, so it
>>> wouldn't conflict with a generic one). However, if CYW89459 only refers
>>> to specific variants, I think the firmware should be named after the
>>> overall bcm4355 family.
>>>
>>> I'm guessing you intend to ship firmware for this. Would that firmware
>>> work for all 4355 variants, or only the CYW one? If only the CYW one, is
>>> it possible to differentiate between them based on PCI revision ID? Note
>>> that our 4355 has revision ID 12, and Apple specifically calls it 4355C1
>>> (different chip revisions have different firmware builds, which is why I
>>> named our firmware brcmfmac4355c1-pcie). If the CYW variant uses other
>>> revision IDs that do not overlap, maybe we should have different
>>> firmware entries for them with different masks.
>>
>>
>> Can we make a separate table for the OTP Apple chips, something like here :-
>>
>> https://github.com/AdityaGarg8/linux/commit/fc41aac9283d2ba653a8b3191e8c0138c13d8ee1
>
> I do not understand from this email thread why you would need separate
> tables. Can you explain?
>

I think he's proposing we special-case Apple chips into their own
firmware table just to avoid colliding with non-Apple firmware usage,
which is honestly kind of tempting as the safe option if nobody from the
Broadcom/Cypress side is willing to clarify what, exactly, is the
relationship between these chips and what their respective revision
numbers are so we can *correctly* represent them and avoid further
confusion and problems down the line.

You might be able to help with that ;)

- Hector