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, 6 insertions, 4 deletions

diff --git a/sys/dev/fxp/if_fxp.c b/sys/dev/fxp/if_fxp.c
index 80f0bac..69bb5de 100644
--- a/sys/dev/fxp/if_fxp.c
+++ b/sys/dev/fxp/if_fxp.c
@@ -622,7 +622,7 @@ fxp_attach(device_t dev)
 	maxtxseg = sc->flags & FXP_FLAG_EXT_RFA ? FXP_NTXSEG - 1 : FXP_NTXSEG;
 	error = bus_dma_tag_create(NULL, 2, 0, BUS_SPACE_MAXADDR_32BIT,
 	    BUS_SPACE_MAXADDR, NULL, NULL, MCLBYTES * maxtxseg,
-	    maxtxseg, MCLBYTES, 0, &sc->fxp_mtag);
+	    maxtxseg, MCLBYTES, 0, busdma_lock_mutex, &Giant, &sc->fxp_mtag);
 	if (error) {
 		device_printf(dev, "could not allocate dma tag\n");
 		goto fail;
@@ -630,7 +630,8 @@ fxp_attach(device_t dev)
 
 	error = bus_dma_tag_create(NULL, 4, 0, BUS_SPACE_MAXADDR_32BIT,
 	    BUS_SPACE_MAXADDR, NULL, NULL, sizeof(struct fxp_stats), 1,
-	    sizeof(struct fxp_stats), 0, &sc->fxp_stag);
+	    sizeof(struct fxp_stats), 0, busdma_lock_mutex, &Giant,
+	    &sc->fxp_stag);
 	if (error) {
 		device_printf(dev, "could not allocate dma tag\n");
 		goto fail;
@@ -650,7 +651,7 @@ fxp_attach(device_t dev)
 
 	error = bus_dma_tag_create(NULL, 4, 0, BUS_SPACE_MAXADDR_32BIT,
 	    BUS_SPACE_MAXADDR, NULL, NULL, FXP_TXCB_SZ, 1,
-	    FXP_TXCB_SZ, 0, &sc->cbl_tag);
+	    FXP_TXCB_SZ, 0, busdma_lock_mutex, &Giant, &sc->cbl_tag);
 	if (error) {
 		device_printf(dev, "could not allocate dma tag\n");
 		goto fail;
@@ -672,7 +673,8 @@ fxp_attach(device_t dev)
 
 	error = bus_dma_tag_create(NULL, 4, 0, BUS_SPACE_MAXADDR_32BIT,
 	    BUS_SPACE_MAXADDR, NULL, NULL, sizeof(struct fxp_cb_mcs), 1,
-	    sizeof(struct fxp_cb_mcs), 0, &sc->mcs_tag);
+	    sizeof(struct fxp_cb_mcs), 0, busdma_lock_mutex, &Giant,
+	    &sc->mcs_tag);
 	if (error) {
 		device_printf(dev, "could not allocate dma tag\n");
 		goto fail;