diff --git a/sys/dev/cxgbe/adapter.h b/sys/dev/cxgbe/adapter.h
--- a/sys/dev/cxgbe/adapter.h
+++ b/sys/dev/cxgbe/adapter.h
@@ -954,8 +954,6 @@
 	struct resource *regs_res;
 	int msix_rid;
 	struct resource *msix_res;
-	bus_space_handle_t bh;
-	bus_space_tag_t bt;
 	bus_size_t mmio_len;
 	int udbs_rid;
 	struct resource *udbs_res;
@@ -1266,7 +1264,7 @@
 {
 	if (hw_off_limits(sc))
 		MPASS(curthread == sc->reset_thread);
-	return bus_space_read_4(sc->bt, sc->bh, reg);
+	return bus_read_4(sc->regs_res, reg);
 }
 
 static inline void
@@ -1274,7 +1272,7 @@
 {
 	if (hw_off_limits(sc))
 		MPASS(curthread == sc->reset_thread);
-	bus_space_write_4(sc->bt, sc->bh, reg, val);
+	bus_write_4(sc->regs_res, reg, val);
 }
 
 static inline uint64_t
@@ -1283,10 +1281,10 @@
 	if (hw_off_limits(sc))
 		MPASS(curthread == sc->reset_thread);
 #ifdef __LP64__
-	return bus_space_read_8(sc->bt, sc->bh, reg);
+	return bus_read_8(sc->regs_res, reg);
 #else
-	return (uint64_t)bus_space_read_4(sc->bt, sc->bh, reg) +
-	    ((uint64_t)bus_space_read_4(sc->bt, sc->bh, reg + 4) << 32);
+	return (uint64_t)bus_read_4(sc->regs_res, reg) +
+	    ((uint64_t)bus_read_4(sc->regs_res, reg + 4) << 32);
 
 #endif
 }
@@ -1297,10 +1295,10 @@
 	if (hw_off_limits(sc))
 		MPASS(curthread == sc->reset_thread);
 #ifdef __LP64__
-	bus_space_write_8(sc->bt, sc->bh, reg, val);
+	bus_write_8(sc->regs_res, reg, val);
 #else
-	bus_space_write_4(sc->bt, sc->bh, reg, val);
-	bus_space_write_4(sc->bt, sc->bh, reg + 4, val>> 32);
+	bus_write_4(sc->regs_res, reg, val);
+	bus_write_4(sc->regs_res, reg + 4, val>> 32);
 #endif
 }
 
diff --git a/sys/dev/cxgbe/t4_iov.c b/sys/dev/cxgbe/t4_iov.c
--- a/sys/dev/cxgbe/t4_iov.c
+++ b/sys/dev/cxgbe/t4_iov.c
@@ -54,8 +54,6 @@
 	int pf;
 	int regs_rid;
 	struct resource *regs_res;
-	bus_space_handle_t bh;
-	bus_space_tag_t bt;
 };
 
 struct {
@@ -147,7 +145,7 @@
 t4iov_read_reg(struct t4iov_softc *sc, uint32_t reg)
 {
 
-	return bus_space_read_4(sc->bt, sc->bh, reg);
+	return bus_read_4(sc->regs_res, reg);
 }
 
 static int	t4iov_attach_child(device_t dev);
@@ -255,8 +253,6 @@
 		device_printf(dev, "cannot map registers.\n");
 		return (ENXIO);
 	}
-	sc->bt = rman_get_bustag(sc->regs_res);
-	sc->bh = rman_get_bushandle(sc->regs_res);
 
 	pl_rev = t4iov_read_reg(sc, A_PL_REV);
 	whoami = t4iov_read_reg(sc, A_PL_WHOAMI);
diff --git a/sys/dev/cxgbe/t4_main.c b/sys/dev/cxgbe/t4_main.c
--- a/sys/dev/cxgbe/t4_main.c
+++ b/sys/dev/cxgbe/t4_main.c
@@ -2699,8 +2699,8 @@
 {
 	/* This is a t4_write_reg without the hw_off_limits check. */
 	MPASS(sc->error_flags & HW_OFF_LIMITS);
-	bus_space_write_4(sc->bt, sc->bh, A_PL_RST,
-			  F_PIORSTMODE | F_PIORST | F_AUTOPCIEPAUSE);
+	bus_write_4(sc->regs_res, A_PL_RST,
+	    F_PIORSTMODE | F_PIORST | F_AUTOPCIEPAUSE);
 	pause("pl_rst", 1 * hz);		/* Wait 1s for reset */
 	return (0);
 }
@@ -4067,8 +4067,6 @@
 		device_printf(sc->dev, "cannot map registers.\n");
 		return (ENXIO);
 	}
-	sc->bt = rman_get_bustag(sc->regs_res);
-	sc->bh = rman_get_bushandle(sc->regs_res);
 	sc->mmio_len = rman_get_size(sc->regs_res);
 	setbit(&sc->doorbells, DOORBELL_KDB);