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, 2 insertions, 1 deletions

diff --git a/sys/i386/acpica/acpi_wakeup.c b/sys/i386/acpica/acpi_wakeup.c
index 306533e..81a396a 100644
--- a/sys/i386/acpica/acpi_wakeup.c
+++ b/sys/i386/acpica/acpi_wakeup.c
@@ -315,7 +315,8 @@ acpi_alloc_wakeup_handler(void)
 	if (bus_dma_tag_create(/* parent */ NULL, /* alignment */ 2, 0,
 			       /* lowaddr below 1MB */ 0x9ffff,
 			       /* highaddr */ BUS_SPACE_MAXADDR, NULL, NULL,
-				PAGE_SIZE, 1, PAGE_SIZE, 0, &acpi_waketag) != 0) {
+				PAGE_SIZE, 1, PAGE_SIZE, 0, busdma_lock_mutex,
+				&Giant, &acpi_waketag) != 0) {
 		printf("acpi_alloc_wakeup_handler: unable to create wake tag\n");
 		return;
 	}