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

3 files changed, 7 insertions, 3 deletions

diff --git a/sys/dev/ida/ida.c b/sys/dev/ida/ida.c
index c141749..ea273a1 100644
--- a/sys/dev/ida/ida.c
+++ b/sys/dev/ida/ida.c
@@ -205,7 +205,8 @@ ida_init(struct ida_softc *ida)
 	    /*filter*/NULL, /*filterarg*/NULL,
 	    IDA_QCB_MAX * sizeof(struct ida_hardware_qcb),
 	    /*nsegments*/1, /*maxsegsz*/BUS_SPACE_MAXSIZE_32BIT,
-	    /*flags*/0, &ida->hwqcb_dmat);
+	    /*flags*/0, /*lockfunc*/busdma_lock_mutex, /*lockarg*/&Giant,
+	    &ida->hwqcb_dmat);
 	if (error)
                 return (ENOMEM);
 
@@ -215,7 +216,8 @@ ida_init(struct ida_softc *ida)
 	    /*lowaddr*/BUS_SPACE_MAXADDR, /*highaddr*/BUS_SPACE_MAXADDR,
 	    /*filter*/NULL, /*filterarg*/NULL,
 	    /*maxsize*/MAXBSIZE, /*nsegments*/IDA_NSEG,
-	    /*maxsegsz*/BUS_SPACE_MAXSIZE_32BIT, /*flags*/0, &ida->buffer_dmat);
+	    /*maxsegsz*/BUS_SPACE_MAXSIZE_32BIT, /*flags*/0,
+	    /*lockfunc*/busdma_lock_mutex, /*lockarg*/&Giant, &ida->buffer_dmat);
 	if (error)
                 return (ENOMEM);
 
diff --git a/sys/dev/ida/ida_eisa.c b/sys/dev/ida/ida_eisa.c
index a6f3419..0c7ac5f 100644
--- a/sys/dev/ida/ida_eisa.c
+++ b/sys/dev/ida/ida_eisa.c
@@ -303,6 +303,8 @@ ida_eisa_attach(device_t dev)
 		/* nsegments	*/	IDA_NSEG,
 		/* maxsegsize	*/	BUS_SPACE_MAXSIZE_32BIT,
 		/* flags	*/	BUS_DMA_ALLOCNOW,
+		/* lockfunc	*/	NULL,
+		/* lockarg	*/	NULL,
 		&ida->parent_dmat);
 
 	if (error != 0) {
diff --git a/sys/dev/ida/ida_pci.c b/sys/dev/ida/ida_pci.c
index c836de0..92cdba7 100644
--- a/sys/dev/ida/ida_pci.c
+++ b/sys/dev/ida/ida_pci.c
@@ -267,7 +267,7 @@ ida_pci_attach(device_t dev)
 	    /*highaddr*/BUS_SPACE_MAXADDR, /*filter*/NULL, /*filterarg*/NULL,
 	    /*maxsize*/MAXBSIZE, /*nsegments*/IDA_NSEG,
 	    /*maxsegsize*/BUS_SPACE_MAXSIZE_32BIT, /*flags*/BUS_DMA_ALLOCNOW,
-	    &ida->parent_dmat);
+	    /*lockfunc*/NULL, /*lockarg*/NULL, &ida->parent_dmat);
 	if (error != 0) {
 		device_printf(dev, "can't allocate DMA tag\n");
 		ida_free(ida);