Mega busdma API commit.

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

1 files changed, 2 insertions, 0 deletions

diff --git a/sys/dev/an/if_an_pci.c b/sys/dev/an/if_an_pci.c
index eba74db..8ed13c6 100644
--- a/sys/dev/an/if_an_pci.c
+++ b/sys/dev/an/if_an_pci.c
@@ -216,6 +216,8 @@ an_attach_pci(dev)
 			       1,			/* nsegments */
 			       0xffff,			/* maxsegsize XXX */
 			       BUS_DMA_ALLOCNOW,	/* flags */
+			       NULL,			/* lockfunc */
+			       NULL,			/* lockarg */
 			       &sc->an_dtag);
 		if (error) {
 			printf("an%d: couldn't get DMA region\n", unit);