add a newbus method for obtaining the bus's bus_dma_tag_t... This is

required by arches like sparc64 (not yet implemented) and sun4v where there
are seperate IOMMU's for each PCI bus...  For all other arches, it will
end up returning NULL, which makes it a no-op...

Convert a few drivers (the ones we've been working w/ on sun4v) to the
new convection...  Eventually all drivers will need to replace the parent
tag of NULL, w/ bus_get_dma_tag(dev), though dev is usually different for
each driver, and will require hand inspection...

Reviewed by:	scottl (earlier version)

1 files changed, 11 insertions, 0 deletions

diff --git a/sys/kern/bus_if.m b/sys/kern/bus_if.m
index 05aad09..529b506 100644
--- a/sys/kern/bus_if.m
+++ b/sys/kern/bus_if.m
@@ -529,3 +529,14 @@ METHOD void hinted_child {
 	const char *	_dname;
 	int		_dunit;
 };
+
+/**
+ * @brief Returns bus_dma_tag_t for use w/ devices on the bus.
+ *
+ * @param _dev		the parent device of @p _child
+ * @param _child	the device to which the tag will belong
+ */
+METHOD bus_dma_tag_t get_dma_tag {
+	device_t	_dev;
+	device_t	_child;
+} DEFAULT bus_generic_get_dma_tag;