In message <[EMAIL PROTECTED]> Doug
Rabson writes:
: I'm uneasy about using the flags for this since I'm vaguely reserving the
: upper 16 bits of flags for bus-specific purposes (although I haven't
: formalised this).
:
: For allocating aligned regions with pnp, I simply looped in the caller
: trying each specific range until one was free (see isa_find_port() in
: isa_common.c). This is ugly but it does work.
:
: In the long run, I think we need either an extra parameter to
: rman_reserve_resource() or a new api rman_reserve_resource_aligned().
: This also implies changing the method BUS_ALLOC_RESOURCE() or adding
: BUS_ALLOC_RESOURCE_ALIGNED().
Well, with just 6 bits one could handle any alignment requirement up
to 2^(2^6).
We have 6 bits left. If this were the alignment requirement, a value
of 0 would mean 2^0 or 1, which is the current behavior. More
restrictive alignment requirements could be encoded easily. No ABI or
API change needed.
#define RF_ALIGNMENT_MASK 0xfc00
#define RF_ALIGNMENT_SHIFT 10
#define RF_ALIGNMENT_LOG2(x) (x << RF_ALIGNMENT_SHIFT)
Warner
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