brcmfmac: simplify conditional logic in module Makefile

[ngie]

Summary

Use ${FOO:U0} as a shorthand default instead of trying to achieve
the same using a longform method, e.g., defined(FOO) && ${FOO} > 0.

This reduces Makefile complexity, making it easier for humans to read
what the code is doing and avoids potential errors in the Makefile
(typos, etc).

Test Plan

Built this change several times with mfsbsd successfully.

[bz]

The module is not built at all so I wonder if you actually built it with mfsbsd.

That said, If we do this we should similarly apply this to iwlwifi, rtw88, rtw89, mt76, ath1/2/3k Makefile BUT I do have outstanding changes to them in my local tree.
Would you mind if I do have a look at my local changes first before we apply this to all of them?

[ngie]

In D58448#1340980, @bz wrote:

The module is not built at all so I wonder if you actually built it with mfsbsd.

I have other outstanding diffs on a branch which are required to get brcm to build/install: https://github.com/ngie-eign/freebsd-src/tree/brcm-polish . I'm trying to get a working driver on my mid-2010s MacBooks.

That said, If we do this we should similarly apply this to iwlwifi, rtw88, rtw89, mt76, ath1/2/3k Makefile BUT I do have outstanding changes to them in my local tree.
Would you mind if I do have a look at my local changes first before we apply this to all of them?

Sure!

[bz]

In D58448#1341087, @ngie wrote:

In D58448#1340980, @bz wrote:

The module is not built at all so I wonder if you actually built it with mfsbsd.

I have other outstanding diffs on a branch which are required to get brcm to build/install: https://github.com/ngie-eign/freebsd-src/tree/brcm-polish . I'm trying to get a working driver on my mid-2010s MacBooks.

brcmfmac compiles on arm64 and amd64; that's not the issue; loading firmware will fail on arm64 (and possibly amd64) because of trouble with copies to IO space.

BUT the driver will do NOTHING even if you get it loaded as a massive piece of compat code is missing, so there is little point in even trying to at this point... unless you want to go and write that code clean room.

[ngie]

In D58448#1341093, @bz wrote:

In D58448#1341087, @ngie wrote:

In D58448#1340980, @bz wrote:

The module is not built at all so I wonder if you actually built it with mfsbsd.

I have other outstanding diffs on a branch which are required to get brcm to build/install: https://github.com/ngie-eign/freebsd-src/tree/brcm-polish . I'm trying to get a working driver on my mid-2010s MacBooks.

brcmfmac compiles on arm64 and amd64; that's not the issue; loading firmware will fail on arm64 (and possibly amd64) because of trouble with copies to IO space.

BUT the driver will do NOTHING even if you get it loaded as a massive piece of compat code is missing, so there is little point in even trying to at this point... unless you want to go and write that code clean room.

Can you provide more details to help give me a head start? I have a bit of an abundance of free time on my hands currently and would like to get this working.

[ngie]

The alternative format that I prefer that's a bit more explicit (and more of a longhand form) is something like:

# Enable ACPI support in driver.
#
# Enables suspend/resume support on x86 machines ...
BRCMFMAC_ACPI?= 0

That way you can document what the knobs do, what models the knobs might affect, etc, and the knobs in and of themselves become self-documenting. Downside is now you need to put the knobs in the KERNCONFs as well as the module Makefiles.
Thoughts?