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, 7 insertions, 2 deletions

diff --git a/sys/dev/firewire/fwdma.c b/sys/dev/firewire/fwdma.c
index 14b49039e692..a16d233c4dd3 100644
--- a/sys/dev/firewire/fwdma.c
+++ b/sys/dev/firewire/fwdma.c
@@ -38,6 +38,8 @@
 #include <sys/types.h>
 #include <sys/kernel.h>
 #include <sys/malloc.h>
+#include <sys/lock.h>
+#include <sys/mutex.h>
 
 #include <sys/bus.h>
 #include <machine/bus.h>
@@ -74,7 +76,8 @@ fwdma_malloc(struct firewire_comm *fc, int alignment, bus_size_t size,
 		/*maxsize*/ size,
 		/*nsegments*/ 1,
 		/*maxsegsz*/ BUS_SPACE_MAXSIZE_32BIT,
-		/*flags*/ BUS_DMA_ALLOCNOW, &dma->dma_tag);
+		/*flags*/ BUS_DMA_ALLOCNOW,
+		/*lockfunc*/busdma_lock_mutex,/*lockarg*/&Giant, &dma->dma_tag);
 	if (err) {
 		printf("fwdma_malloc: failed(1)\n");
 		return(NULL);
@@ -167,7 +170,9 @@ fwdma_malloc_multiseg(struct firewire_comm *fc, int alignment,
 			/*maxsize*/ ssize,
 			/*nsegments*/ 1,
 			/*maxsegsz*/ BUS_SPACE_MAXSIZE_32BIT,
-			/*flags*/ BUS_DMA_ALLOCNOW, &am->dma_tag)) {
+			/*flags*/ BUS_DMA_ALLOCNOW,
+			/*lockfunc*/busdma_lock_mutex,
+			/*lockarg*/&Giant, &am->dma_tag)) {
 		printf("fwdma_malloc_multiseg: tag_create failed\n");
 		free(am, M_FW);
 		return(NULL);