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, 10 insertions, 0 deletions

diff --git a/sys/dev/mly/mly.c b/sys/dev/mly/mly.c
index cdf1943..d220773 100644
--- a/sys/dev/mly/mly.c
+++ b/sys/dev/mly/mly.c
@@ -407,6 +407,8 @@ mly_pci_attach(struct mly_softc *sc)
 			   MAXBSIZE, MLY_MAX_SGENTRIES,	/* maxsize, nsegments */
 			   BUS_SPACE_MAXSIZE_32BIT,	/* maxsegsize */
 			   BUS_DMA_ALLOCNOW,		/* flags */
+			   NULL,			/* lockfunc */
+			   NULL,			/* lockarg */
 			   &sc->mly_parent_dmat)) {
 	mly_printf(sc, "can't allocate parent DMA tag\n");
 	goto fail;
@@ -423,6 +425,8 @@ mly_pci_attach(struct mly_softc *sc)
 			   MAXBSIZE, MLY_MAX_SGENTRIES,	/* maxsize, nsegments */
 			   BUS_SPACE_MAXSIZE_32BIT,	/* maxsegsize */
 			   0,				/* flags */
+			   busdma_lock_mutex,		/* lockfunc */
+			   &Giant,			/* lockarg */
 			   &sc->mly_buffer_dmat)) {
 	mly_printf(sc, "can't allocate buffer DMA tag\n");
 	goto fail;
@@ -439,6 +443,8 @@ mly_pci_attach(struct mly_softc *sc)
 			   sizeof(union mly_command_packet) * MLY_MAX_COMMANDS, 1,	/* maxsize, nsegments */
 			   BUS_SPACE_MAXSIZE_32BIT,	/* maxsegsize */
 			   0,				/* flags */
+			   busdma_lock_mutex,		/* lockfunc */
+			   &Giant,			/* lockarg */
 			   &sc->mly_packet_dmat)) {
 	mly_printf(sc, "can't allocate command packet DMA tag\n");
 	goto fail;
@@ -586,6 +592,8 @@ mly_sg_map(struct mly_softc *sc)
 			   segsize, 1,			/* maxsize, nsegments */
 			   BUS_SPACE_MAXSIZE_32BIT,	/* maxsegsize */
 			   0,				/* flags */
+			   busdma_lock_mutex,		/* lockfunc */
+			   &Giant,			/* lockarg */
 			   &sc->mly_sg_dmat)) {
 	mly_printf(sc, "can't allocate scatter/gather DMA tag\n");
 	return(ENOMEM);
@@ -639,6 +647,8 @@ mly_mmbox_map(struct mly_softc *sc)
 			   sizeof(struct mly_mmbox), 1,	/* maxsize, nsegments */
 			   BUS_SPACE_MAXSIZE_32BIT,	/* maxsegsize */
 			   0,				/* flags */
+			   busdma_lock_mutex,		/* lockfunc */
+			   &Giant,			/* lockarg */
 			   &sc->mly_mmbox_dmat)) {
 	mly_printf(sc, "can't allocate memory mailbox DMA tag\n");
 	return(ENOMEM);