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

2 files changed, 8 insertions, 4 deletions

diff --git a/sys/dev/isp/isp_pci.c b/sys/dev/isp/isp_pci.c
index 9636a7f..0bb854f 100644
--- a/sys/dev/isp/isp_pci.c
+++ b/sys/dev/isp/isp_pci.c
@@ -1097,7 +1097,8 @@ isp_pci_mbxdma(struct ispsoftc *isp)
 
 	ISP_UNLOCK(isp);
 	if (bus_dma_tag_create(NULL, 1, slim+1, alim, alim,
-	    NULL, NULL, BUS_SPACE_MAXSIZE, ISP_NSEGS, slim, 0, &pcs->dmat)) {
+	    NULL, NULL, BUS_SPACE_MAXSIZE, ISP_NSEGS, slim, 0, 
+	    busdma_lock_mutex, &Giant, &pcs->dmat)) {
 		isp_prt(isp, ISP_LOGERR, "could not create master dma tag");
 		ISP_LOCK(isp);
 		return(1);
@@ -1131,7 +1132,8 @@ isp_pci_mbxdma(struct ispsoftc *isp)
 
 	ns = (len / PAGE_SIZE) + 1;
 	if (bus_dma_tag_create(pcs->dmat, QENTRY_LEN, slim+1, alim, alim,
-	    NULL, NULL, len, ns, slim, 0, &isp->isp_cdmat)) {
+	    NULL, NULL, len, ns, slim, 0, busdma_lock_mutex, &Giant,
+	    &isp->isp_cdmat)) {
 		isp_prt(isp, ISP_LOGERR,
 		    "cannot create a dma tag for control spaces");
 		free(pcs->dmaps, M_DEVBUF);
diff --git a/sys/dev/isp/isp_sbus.c b/sys/dev/isp/isp_sbus.c
index d2af1a5..47bb9ef 100644
--- a/sys/dev/isp/isp_sbus.c
+++ b/sys/dev/isp/isp_sbus.c
@@ -491,7 +491,8 @@ isp_sbus_mbxdma(struct ispsoftc *isp)
 	if (bus_dma_tag_create(NULL, 1, BUS_SPACE_MAXADDR_24BIT-1,
 	    BUS_SPACE_MAXADDR_32BIT, BUS_SPACE_MAXADDR_32BIT,
 	    NULL, NULL, BUS_SPACE_MAXSIZE_32BIT, ISP_NSEGS,
-	    BUS_SPACE_MAXADDR_24BIT, 0, &sbs->dmat)) {
+	    BUS_SPACE_MAXADDR_24BIT, 0, busdma_lock_mutex, &Giant,
+	    &sbs->dmat)) {
 		isp_prt(isp, ISP_LOGERR, "could not create master dma tag");
 		ISP_LOCK(isp);
 		return(1);
@@ -522,7 +523,8 @@ isp_sbus_mbxdma(struct ispsoftc *isp)
 	ns = (len / PAGE_SIZE) + 1;
 	if (bus_dma_tag_create(sbs->dmat, QENTRY_LEN, BUS_SPACE_MAXADDR_24BIT-1,
 	    BUS_SPACE_MAXADDR_32BIT, BUS_SPACE_MAXADDR_32BIT, NULL, NULL,
-	    len, ns, BUS_SPACE_MAXADDR_24BIT, 0, &isp->isp_cdmat)) {
+	    len, ns, BUS_SPACE_MAXADDR_24BIT, 0, busdma_lock_mutex, &Giant,
+	    &isp->isp_cdmat)) {
 		isp_prt(isp, ISP_LOGERR,
 		    "cannot create a dma tag for control spaces");
 		free(sbs->dmaps, M_DEVBUF);