Add two new arguments to bus_dma_tag_create(): lockfunc and lockfuncarg.
Lockfunc allows a driver to provide a function for managing its locking
semantics while using busdma. At the moment, this is used for the
asynchronous busdma_swi and callback mechanism. Two lockfunc implementations
are provided: busdma_lock_mutex() performs standard mutex operations on the
mutex that is specified from lockfuncarg. dftl_lock() is a panic
implementation and is defaulted to when NULL, NULL are passed to
bus_dma_tag_create(). The only time that NULL, NULL should ever be used is
when the driver ensures that bus_dmamap_load() will not be deferred.
Drivers that do not provide their own locking can pass
busdma_lock_mutex,&Giant args in order to preserve the former behaviour.
sparc64 and powerpc do not provide real busdma_swi functions, so this is
largely a noop on those platforms. The busdma_swi on is64 is not properly
locked yet, so warnings will be emitted on this platform when busdma
callback deferrals happen.
If anyone gets panics or warnings from dflt_lock() being called, please
let me know right away.
Reviewed by: tmm, gibbs
The current name is confusing, because it indicates to
the client that a bus_dmamap_sync() operation is not
necessary when the flag is specified, which is wrong.
The main purpose of this flag is to hint the underlying
architecture that DMA memory should be mapped in a coherent
way, but the architecture can ignore it. But if the
architecture does supports coherent mapping of memory, then
it makes bus_dmamap_sync() calls cheap.
This flag is the same as the one in NetBSD's Bus DMA.
Reviewed by: gibbs, scottl, des (implicitly)
Approved by: re@ (jhb)
BUS_DMASYNC_ definitions remain as before. The does not change the ABI,
and reverts the API to be a bit more compatible and flexible. This has
survived a full 'make universe'.
Approved by: re (bmah)
o do not use the in* and out* functions. These functions are used by
legacy drivers and thus must have ia32 compatible behaviour. Hence,
they need to have fences. Using these functions for newbus would
then pessimize performance.
o remove the conditional compilation of PIO and/or MEMIO support. It's
a PITA without having any significant benefit. We always support them
both. Since there are no I/O ports on ia64 (they are simulated by the
chipset by translating memory mapped I/O to predefined uncacheable
memory regions) the only difference between PIO and MEMIO is in the
address calculation. There should be enough ILP that can be exploited
here that making these computations compile-time conditional is not
worth it. We now also don't use the read* and write* functions.
o Add the missing *_8 variants. They were missing, although not missed.
It's for completeness.
o Do not add the fences that were present in the low-level support
functions here. We're using uncacheable memory, which means that
accesses are in program order. Change the barrier implementation
to not only do a memory fence, but also an acceptance fence. This
should more reliably synchronize drivers with the hardware. The
memory fence enforces ordering, but does not imply visibility (ie
the access does not necessarily have happened). This is what the
acceptance deals with.
cpufunc.h cleanup:
o Remove the low-level memory mapped I/O support functions. They are
not used. Keep the low-level I/O port access functions for legacy
drivers and add fences to ensure ia32 compatibility.
o Remove the syscons specific functions now that we have moved the
proper definitions where they belong.
o Replace the ia64_port_address() and ia64_memory_address() functions
with macros. There's a bigger change inline functions get inlined
when there aren't function callsi and the calculations are simply
enough to do it with macros.
Replace the one reference to ia64_memory address in mp_machdep.c to
use the macro.
device drivers for bus system with other endinesses than the CPU (using
interfaces compatible to NetBSD):
- bwap16() and bswap32(). These have optimized implementations on some
architectures; for those that don't, there exist generic implementations.
- macros to convert from a certain byte order to host byte order and vice
versa, using a naming scheme like le16toh(), htole16().
These are implemented using the bswap functions.
- stream bus space access functions, which do not perform a byte order
conversion (while the normal access functions would if the bus endianess
differs from the CPU endianess).
htons(), htonl(), ntohs() and ntohl() are implemented using the new
functions above for kernel usage. None of the above interfaces is currently
exported to user land.
Make use of the new functions in a few places where local implementations
of the same functionality existed.
Reviewed by: mike, bde
Tested on alpha by: mike
not work on any real hardware (or fully work on any simulator). Much more
needs to happen before this is actually functional but its nice to see
the FreeBSD copyright message appear in the ia64 simulator.
