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/iir/iir.c b/sys/dev/iir/iir.c
index 6f0fb9c..e0a1999 100644
--- a/sys/dev/iir/iir.c
+++ b/sys/dev/iir/iir.c
@@ -212,6 +212,7 @@ iir_init(struct gdt_softc *gdt)
                            /*maxsize*/MAXBSIZE, /*nsegments*/GDT_MAXSG,
                            /*maxsegsz*/BUS_SPACE_MAXSIZE_32BIT,
                            /*flags*/BUS_DMA_ALLOCNOW,
+			   /*lockfunc*/busdma_lock_mutex, /*lockarg*/&Giant,
                            &gdt->sc_buffer_dmat) != 0) {
         printf("iir%d: bus_dma_tag_create(...,gdt->sc_buffer_dmat) failed\n",
                gdt->sc_hanum);
@@ -230,7 +231,8 @@ iir_init(struct gdt_softc *gdt)
                            GDT_MAXCMDS * sizeof(struct gdt_ccb), /* maxsize */
                            /*nsegments*/1,
                            /*maxsegsz*/BUS_SPACE_MAXSIZE_32BIT,
-                           /*flags*/0, &gdt->sc_gccb_dmat) != 0) {
+			   /*flags*/0, /*lockfunc*/busdma_lock_mutex,
+			   /*lockarg*/&Giant, &gdt->sc_gccb_dmat) != 0) {
         printf("iir%d: bus_dma_tag_create(...,gdt->sc_gccb_dmat) failed\n",
                gdt->sc_hanum);
         return (1);