Add in a simple API for memory barriers to machine/bus.h:

- barrier_read() enforces a memory read barrier
- barrier_write() enforces a memory write barrier
- barrier_rw() enforces a memory read/write barrier

1 files changed, 12 insertions, 0 deletions

diff --git a/sys/alpha/include/bus.h b/sys/alpha/include/bus.h
index 7fe2726..1810c4b 100644
--- a/sys/alpha/include/bus.h
+++ b/sys/alpha/include/bus.h
@@ -364,6 +364,18 @@ void busspace_generic_barrier(struct alpha_busspace *space,
 #define bus_space_barrier(t, h, o, l, f) \
 	(t)->ab_ops->abo_barrier(t, (h)+(o), l, f)
 
+#define barrier_read \
+	bus_space_barrier(busspace_isa_mem, 0, BUS_SPACE_UNRESTRICTED,	\
+	    BUS_SPACE_BARRIER_READ)
+
+#define barrier_write \
+	bus_space_barrier(busspace_isa_mem, 0, BUS_SPACE_UNRESTRICTED,	\
+	    BUS_SPACE_BARRIER_WRITE)
+
+#define barrier_rw \
+	bus_space_barrier(busspace_isa_mem, 0, BUS_SPACE_UNRESTRICTED,	\
+	    BUS_SPACE_BARRIER_READ | BUS_SPACE_BARRIER_WRITE)
+
 /*
  * Flags used in various bus DMA methods.
  */