acpi_spmc(4): Factor out testing for present DSMs/functions

[olce]

Summary

Since we are now keeping in the softc the information about which DSM
functions are available (in supported_functions[]), the 'dsms' field
there is somewhat redundant.

Make it completely redundant by keeping the bit representing the
enumeration function itself in each element of supported_functions[],
and then remove the field.

As a result, convert has_dsm() to rely on supports_function().

Adapt acpi_spmc_dsm_check_functions() so that it does not take into
account the enumeration function bit.

While here, use the self-explanatory stance
IDX_TO_BIT(DSM_ENUM_FUNCTIONS) instead of a hardcoded 1.

Sponsored by: The FreeBSD Foundation

[obiwac]

yeah, this logic is much better

sys/dev/acpica/acpi_spmc.c

246–261

can we just move these functions in the revision they were added? esp since at least supports_function() will have more history than just the commit in which it was added, which we'd thus lose in a blame

406–407

i remember this was moved in a revision somewhere down the stack, and here it's just being moved back. Can we just not move it in that revision?

[olce]

sys/dev/acpica/acpi_spmc.c

246–261

Sure.

406–407

Yes. I moved the KASSERT() to be closer to the first use assuming the checked invariant, which causes it to move back and forth. Will remove that.

[olce]

Impacts of changes in earlier revisions, no real change.