pms/freebsd: fix compiler warnings

[rlibby]

Summary

• A number of unused variable warnings,
• a missing prototype warning (actually a dead function),
• and a potential use of an uninitialized variable.

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This patch is just for the code under sys/dev/pms/freebsd, which I am assuming we are free to patch and maintain.

I also have a set of patches that would fix the rest of the warnings in pms (outside of pms/freebsd) and actually allow enabling warnings for the module. I assume there is an upstream somewhere, but I haven't been able to find it yet.

Test Plan

buildkernel

Additionally I enabled warnings for pms (after applying those other patches) and ensured a clean build.

[pfg]

Upstream indeed seems to have disappeared but Benno Rice may know better.

sys/dev/pms/freebsd/driver/ini/src/agtiapi.c

2078 ↗

(On Diff #34016)

Interesting change. The original code seems to have had some chance for undefined values.

[rlibby]

In D12683#263679, @pfg wrote:

Upstream indeed seems to have disappeared but Benno Rice may know better.

Thanks, I'll ping him.

sys/dev/pms/freebsd/driver/ini/src/agtiapi.c

2078 ↗

(On Diff #34016)

Yes, although it looks like in practice pmcsc being NULL would cause us to page fault in agtiapi_GetCCB. This was the straightforward fix for the uninitialized variable warning, but reading further it looks like the pmcsc is never NULL from the only caller, agtiapi_cam_action. Would you like this to be fixed up further to KASSERT(pmcsc != NULL) at the top and then remove the pmcsc != NULL guard altogether?

[pfg]

FWIW, I sent benno some typo fixes long ago but I never heard from him (I'll dig up the patches again) ... the upstream email address is no more.

sys/dev/pms/freebsd/driver/ini/src/agtiapi.c

2078 ↗

(On Diff #34016)

I think it's OK as it is, but I have no experience with this driver.