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
- Sanitize dpt_alloc().
- Add helper functions for resource alloc/release.
- Add detach method.
- Relocate definition of devclass_t.
- Move some debugging output behind bootverbose.
- Implement an identify method for ISA devices
but don't use it right now.
- Add support for ISA based DPT adapters (this doesn't quite work yet).
- Sync dpt_eisa.c with my local copy.
- Simplify how EISA IDs are matched.
- Prototype.
- Formatting nits.
- Conform to how I do things in dpt_pci.c/dpt_isa.c.
- Modify dpt_scsi.c:dpt_alloc() to DTRT with newbus.
- Add some comments to dpt_scsi.c:dpt_pio_get_conf().
- Add additional check to dpt_scsi.c:dpt_get_conf().
- Add some useful error messages to dpt_scsi.c:dpt_init().
