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, 4 insertions, 1 deletions

diff --git a/sys/dev/firewire/fwohci_pci.c b/sys/dev/firewire/fwohci_pci.c
index 9745ce8..044621f 100644
--- a/sys/dev/firewire/fwohci_pci.c
+++ b/sys/dev/firewire/fwohci_pci.c
@@ -45,6 +45,8 @@
 #include <machine/bus.h>
 #include <sys/rman.h>
 #include <sys/malloc.h>
+#include <sys/lock.h>
+#include <sys/mutex.h>
 #include <machine/resource.h>
 
 #if __FreeBSD_version < 500000
@@ -299,7 +301,8 @@ fwohci_pci_attach(device_t self)
 				/*nsegments*/0x20,
 				/*maxsegsz*/0x8000,
 				/*flags*/BUS_DMA_ALLOCNOW,
-				&sc->fc.dmat);
+				/*lockfunc*/busdma_lock_mutex,
+				/*lockarg*/&Giant, &sc->fc.dmat);
 	if (err != 0) {
 		printf("fwohci_pci_attach: Could not allocate DMA tag "
 			"- error %d\n", err);