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, 3 insertions, 1 deletions

diff --git a/sys/dev/aic7xxx/ahd_pci.c b/sys/dev/aic7xxx/ahd_pci.c
index 2f1c8ed..9f7a1b5 100644
--- a/sys/dev/aic7xxx/ahd_pci.c
+++ b/sys/dev/aic7xxx/ahd_pci.c
@@ -28,7 +28,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- * $Id: //depot/aic7xxx/freebsd/dev/aic7xxx/ahd_pci.c#13 $
+ * $Id: ahd_pci.c,v 1.8 2003/05/03 23:27:57 gibbs Exp $
  *
  * $FreeBSD$
  */
@@ -123,6 +123,8 @@ ahd_pci_attach(device_t dev)
 				   /*nsegments*/AHD_NSEG,
 				   /*maxsegsz*/AHD_MAXTRANSFER_SIZE,
 				   /*flags*/0,
+				   /*lockfunc*/busdma_lock_mutex,
+				   /*lockarg*/&Giant,
 				   &ahd->parent_dmat);
 
 	if (error != 0) {