[bhnd] Clean up bhnd resource handling and inherited bus methods

To facilitate use by SoC implementors working with bhnd-inheriting fdt/nexus
drivers:

* Splits bhnd_bus method implementations into generic bus implementations
  (bhnd_bus_generic) and generic bhnd(4) driver implementations (bhnd_generic)
* Simplifies bhnd resource handling, allowing bhnd bus implementations to
  support bhnd resource activation by implementing the standard BUS_*
  resource APIs and BHND_BUS_ACTIVATE_RESOURCE().

Submitted by:	Landon Fuller <landonf@landonf.org>
Differential Revision:	https://reviews.freebsd.org/D5758

6 files changed, 263 insertions, 361 deletions

diff --git a/sys/dev/bhnd/bhnd.c b/sys/dev/bhnd/bhnd.c
index 860d58d65fe9..01911f6353ce 100644
--- a/sys/dev/bhnd/bhnd.c
+++ b/sys/dev/bhnd/bhnd.c
@@ -90,11 +90,10 @@ static int	compare_descending_probe_order(const void *lhs,
 		    const void *rhs);
 
 /**
- * Helper function for implementing DEVICE_ATTACH().
- * 
- * This function can be used to implement DEVICE_ATTACH() for bhnd(4)
- * bus implementations. It calls device_probe_and_attach() for each
- * of the device's children, in order.
+ * Default bhnd(4) bus driver implementation of DEVICE_ATTACH().
+ *
+ * This implementation calls device_probe_and_attach() for each of the device's
+ * children, in bhnd probe order.
  */
 int
 bhnd_generic_attach(device_t dev)
@@ -120,12 +119,11 @@ bhnd_generic_attach(device_t dev)
 }
 
 /**
- * Helper function for implementing DEVICE_DETACH().
- * 
- * This function can be used to implement DEVICE_DETACH() for bhnd(4)
- * bus implementations. It calls device_detach() for each
- * of the device's children, in reverse order, terminating if
- * any call to device_detach() fails.
+ * Default bhnd(4) bus driver implementation of DEVICE_DETACH().
+ *
+ * This implementation calls device_detach() for each of the the device's
+ * children, in reverse bhnd probe order, terminating if any call to
+ * device_detach() fails.
  */
 int
 bhnd_generic_detach(device_t dev)
@@ -156,12 +154,11 @@ cleanup:
 }
 
 /**
- * Helper function for implementing DEVICE_SHUTDOWN().
+ * Default bhnd(4) bus driver implementation of DEVICE_SHUTDOWN().
  * 
- * This function can be used to implement DEVICE_SHUTDOWN() for bhnd(4)
- * bus implementations. It calls device_shutdown() for each
- * of the device's children, in reverse order, terminating if
- * any call to device_shutdown() fails.
+ * This implementation calls device_shutdown() for each of the device's
+ * children, in reverse bhnd probe order, terminating if any call to
+ * device_shutdown() fails.
  */
 int
 bhnd_generic_shutdown(device_t dev)
@@ -192,12 +189,11 @@ cleanup:
 }
 
 /**
- * Helper function for implementing DEVICE_RESUME().
- * 
- * This function can be used to implement DEVICE_RESUME() for bhnd(4)
- * bus implementations. It calls BUS_RESUME_CHILD() for each
- * of the device's children, in order, terminating if
- * any call to BUS_RESUME_CHILD() fails.
+ * Default bhnd(4) bus driver implementation of DEVICE_RESUME().
+ *
+ * This implementation calls BUS_RESUME_CHILD() for each of the device's
+ * children in bhnd probe order, terminating if any call to BUS_RESUME_CHILD()
+ * fails.
  */
 int
 bhnd_generic_resume(device_t dev)
@@ -227,14 +223,13 @@ cleanup:
 }
 
 /**
- * Helper function for implementing DEVICE_SUSPEND().
- * 
- * This function can be used to implement DEVICE_SUSPEND() for bhnd(4)
- * bus implementations. It calls BUS_SUSPEND_CHILD() for each
- * of the device's children, in reverse order. If any call to
- * BUS_SUSPEND_CHILD() fails, the suspend operation is terminated and
- * any devices that were suspended are resumed immediately by calling
- * their BUS_RESUME_CHILD() methods.
+ * Default bhnd(4) bus driver implementation of DEVICE_SUSPEND().
+ *
+ * This implementation calls BUS_SUSPEND_CHILD() for each of the device's
+ * children in reverse bhnd probe order. If any call to BUS_SUSPEND_CHILD()
+ * fails, the suspend operation is terminated and any devices that were
+ * suspended are resumed immediately by calling their BUS_RESUME_CHILD()
+ * methods.
  */
 int
 bhnd_generic_suspend(device_t dev)
@@ -305,8 +300,8 @@ compare_descending_probe_order(const void *lhs, const void *rhs)
 }
 
 /**
- * Helper function for implementing BHND_BUS_GET_PROBE_ORDER().
- * 
+ * Default bhnd(4) bus driver implementation of BHND_BUS_GET_PROBE_ORDER().
+ *
  * This implementation determines probe ordering based on the device's class
  * and other properties, including whether the device is serving as a host
  * bridge.
@@ -360,14 +355,14 @@ bhnd_generic_get_probe_order(device_t dev, device_t child)
 }
 
 /**
- * Helper function for implementing BHND_BUS_IS_REGION_VALID().
+ * Default bhnd(4) bus driver implementation of BHND_BUS_IS_REGION_VALID().
  * 
  * This implementation assumes that port and region numbers are 0-indexed and
  * are allocated non-sparsely, using BHND_BUS_GET_PORT_COUNT() and
  * BHND_BUS_GET_REGION_COUNT() to determine if @p port and @p region fall
  * within the defined range.
  */
-bool
+static bool
 bhnd_generic_is_region_valid(device_t dev, device_t child,
     bhnd_port_type type, u_int port, u_int region)
 {
@@ -413,14 +408,14 @@ find_nvram_child(device_t dev)
 }
 
 /**
- * Helper function for implementing BHND_BUS_READ_NVRAM_VAR().
+ * Default bhnd(4) bus driver implementation of BHND_BUS_READ_NVRAM_VAR().
  * 
  * This implementation searches @p dev for a valid NVRAM device. If no NVRAM
  * child device is found on @p dev, the request is delegated to the
  * BHND_BUS_READ_NVRAM_VAR() method on the parent
  * of @p dev.
  */
-int
+static int
 bhnd_generic_read_nvram_var(device_t dev, device_t child, const char *name,
     void *buf, size_t *size)
 {
@@ -435,7 +430,7 @@ bhnd_generic_read_nvram_var(device_t dev, device_t child, const char *name,
 }
 
 /**
- * Helper function for implementing BUS_PRINT_CHILD().
+ * Default bhnd(4) bus driver implementation of BUS_PRINT_CHILD().
  * 
  * This implementation requests the device's struct resource_list via
  * BUS_GET_RESOURCE_LIST.
@@ -463,7 +458,7 @@ bhnd_generic_print_child(device_t dev, device_t child)
 }
 
 /**
- * Helper function for implementing BUS_PRINT_CHILD().
+ * Default bhnd(4) bus driver implementation of BUS_PROBE_NOMATCH().
  * 
  * This implementation requests the device's struct resource_list via
  * BUS_GET_RESOURCE_LIST.
@@ -525,7 +520,7 @@ bhnd_child_pnpinfo_str(device_t dev, device_t child, char *buf,
 }
 
 /**
- * Default implementation of implementing BUS_PRINT_CHILD().
+ * Default implementation of BUS_CHILD_LOCATION_STR().
  */
 static int
 bhnd_child_location_str(device_t dev, device_t child, char *buf,
@@ -585,215 +580,6 @@ bhnd_generic_resume_child(device_t dev, device_t child)
 	return bus_generic_resume_child(dev, child);
 }
 
-/**
- * Helper function for implementing BHND_BUS_IS_HOSTB_DEVICE().
- * 
- * If a parent device is available, this implementation delegates the
- * request to the BHND_BUS_IS_HOSTB_DEVICE() method on the parent of @p dev.
- * 
- * If no parent device is available (i.e. on a the bus root), false
- * is returned.
- */
-bool
-bhnd_generic_is_hostb_device(device_t dev, device_t child) {
-	if (device_get_parent(dev) != NULL)
-		return (BHND_BUS_IS_HOSTB_DEVICE(device_get_parent(dev),
-		    child));
-
-	return (false);
-}
-
-/**
- * Helper function for implementing BHND_BUS_IS_HW_DISABLED().
- * 
- * If a parent device is available, this implementation delegates the
- * request to the BHND_BUS_IS_HW_DISABLED() method on the parent of @p dev.
- * 
- * If no parent device is available (i.e. on a the bus root), the hardware
- * is assumed to be usable and false is returned.
- */
-bool
-bhnd_generic_is_hw_disabled(device_t dev, device_t child)
-{
-	if (device_get_parent(dev) != NULL)
-		return (BHND_BUS_IS_HW_DISABLED(device_get_parent(dev), child));
-
-	return (false);
-}
-
-/**
- * Helper function for implementing BHND_BUS_GET_CHIPID().
- * 
- * This implementation delegates the request to the BHND_BUS_GET_CHIPID()
- * method on the parent of @p dev.
- */
-const struct bhnd_chipid *
-bhnd_generic_get_chipid(device_t dev, device_t child) {
-	return (BHND_BUS_GET_CHIPID(device_get_parent(dev), child));
-}
-
-/**
- * Helper function for implementing BHND_BUS_ALLOC_RESOURCE().
- * 
- * This simple implementation of BHND_BUS_ALLOC_RESOURCE() determines
- * any default values via BUS_GET_RESOURCE_LIST(), and calls
- * BHND_BUS_ALLOC_RESOURCE() method of the parent of @p dev.
- * 
- * If no parent device is available, the request is instead delegated to
- * BUS_ALLOC_RESOURCE().
- */
-struct bhnd_resource *
-bhnd_generic_alloc_bhnd_resource(device_t dev, device_t child, int type,
-	int *rid, rman_res_t start, rman_res_t end, rman_res_t count,
-	u_int flags)
-{
-	struct bhnd_resource		*r;
-	struct resource_list		*rl;
-	struct resource_list_entry	*rle;
-	bool				 isdefault;
-	bool				 passthrough;
-
-	passthrough = (device_get_parent(child) != dev);
-	isdefault = RMAN_IS_DEFAULT_RANGE(start, end);
-
-	/* the default RID must always be the first device port/region. */
-	if (!passthrough && *rid == 0) {
-		int rid0 = bhnd_get_port_rid(child, BHND_PORT_DEVICE, 0, 0);
-		KASSERT(*rid == rid0,
-		    ("rid 0 does not map to the first device port (%d)", rid0));
-	}
-
-	/* Determine locally-known defaults before delegating the request. */
-	if (!passthrough && isdefault) {
-		/* fetch resource list from child's bus */
-		rl = BUS_GET_RESOURCE_LIST(dev, child);
-		if (rl == NULL)
-			return (NULL); /* no resource list */
-
-		/* look for matching type/rid pair */
-		rle = resource_list_find(BUS_GET_RESOURCE_LIST(dev, child),
-		    type, *rid);
-		if (rle == NULL)
-			return (NULL);
-
-		/* set default values */
-		start = rle->start;
-		end = rle->end;
-		count = ulmax(count, rle->count);
-	}
-
-	/* Try to delegate to our parent. */
-	if (device_get_parent(dev) != NULL) {
-		return (BHND_BUS_ALLOC_RESOURCE(device_get_parent(dev), child,
-		    type, rid, start, end, count, flags));
-	}
-
-	/* If this is the bus root, use a real bus-allocated resource */
-	r = malloc(sizeof(struct bhnd_resource), M_BHND, M_NOWAIT);
-	if (r == NULL)
-		return NULL;
-
-	/* Allocate the bus resource, marking it as 'direct' (not requiring
-	 * any bus window remapping to perform I/O) */
-	r->direct = true;
-	r->res = BUS_ALLOC_RESOURCE(dev, child, type, rid, start, end,
-	    count, flags);
-
-	if (r->res == NULL) {
-		free(r, M_BHND);
-		return NULL;
-	}
-
-	return (r);
-}
-
-/**
- * Helper function for implementing BHND_BUS_RELEASE_RESOURCE().
- * 
- * This simple implementation of BHND_BUS_RELEASE_RESOURCE() simply calls the
- * BHND_BUS_RELEASE_RESOURCE() method of the parent of @p dev.
- * 
- * If no parent device is available, the request is delegated to
- * BUS_RELEASE_RESOURCE().
- */
-int
-bhnd_generic_release_bhnd_resource(device_t dev, device_t child, int type,
-    int rid, struct bhnd_resource *r)
-{
-	int error;
-
-	/* Try to delegate to the parent. */
-	if (device_get_parent(dev) != NULL)
-		return (BHND_BUS_RELEASE_RESOURCE(device_get_parent(dev), child,
-		    type, rid, r));
-
-	/* Release the resource directly */
-	if (!r->direct) {
-		panic("bhnd indirect resource released without "
-		    "bhnd parent bus");
-	}
-
-	error = BUS_RELEASE_RESOURCE(dev, child, type, rid, r->res);
-	if (error)
-		return (error);
-
-	free(r, M_BHND);
-	return (0);
-}
-
-/**
- * Helper function for implementing BHND_BUS_ACTIVATE_RESOURCE().
- * 
- * This simple implementation of BHND_BUS_ACTIVATE_RESOURCE() simply calls the
- * BHND_BUS_ACTIVATE_RESOURCE() method of the parent of @p dev.
- * 
- * If no parent device is available, the request is delegated to
- * BUS_ACTIVATE_RESOURCE().
- */
-int
-bhnd_generic_activate_bhnd_resource(device_t dev, device_t child, int type,
-	int rid, struct bhnd_resource *r)
-{
-	/* Try to delegate to the parent */
-	if (device_get_parent(dev) != NULL)
-		return (BHND_BUS_ACTIVATE_RESOURCE(device_get_parent(dev),
-		    child, type, rid, r));
-
-	/* Activate the resource directly */
-	if (!r->direct) {
-		panic("bhnd indirect resource released without "
-		    "bhnd parent bus");
-	}
-
-	return (BUS_ACTIVATE_RESOURCE(dev, child, type, rid, r->res));
-};
-
-/**
- * Helper function for implementing BHND_BUS_DEACTIVATE_RESOURCE().
- * 
- * This simple implementation of BHND_BUS_ACTIVATE_RESOURCE() simply calls the
- * BHND_BUS_ACTIVATE_RESOURCE() method of the parent of @p dev.
- * 
- * If no parent device is available, the request is delegated to
- * BUS_DEACTIVATE_RESOURCE().
- */
-int
-bhnd_generic_deactivate_bhnd_resource(device_t dev, device_t child, int type,
-	int rid, struct bhnd_resource *r)
-{
-	if (device_get_parent(dev) != NULL)
-		return (BHND_BUS_DEACTIVATE_RESOURCE(device_get_parent(dev),
-		    child, type, rid, r));
-
-	/* De-activate the resource directly */
-	if (!r->direct) {
-		panic("bhnd indirect resource released without "
-		    "bhnd parent bus");
-	}
-
-	return (BUS_DEACTIVATE_RESOURCE(dev, child, type, rid, r->res));
-};
-
 /*
  * Delegate all indirect I/O to the parent device. When inherited by
  * non-bridged bus implementations, resources will never be marked as
@@ -885,12 +671,12 @@ static device_method_t bhnd_methods[] = {
 	DEVMETHOD(bus_get_dma_tag,		bus_generic_get_dma_tag),
 
 	/* BHND interface */
-	DEVMETHOD(bhnd_bus_alloc_resource,	bhnd_generic_alloc_bhnd_resource),
-	DEVMETHOD(bhnd_bus_release_resource,	bhnd_generic_release_bhnd_resource),
-	DEVMETHOD(bhnd_bus_activate_resource,	bhnd_generic_activate_bhnd_resource),
-	DEVMETHOD(bhnd_bus_activate_resource,	bhnd_generic_deactivate_bhnd_resource),
-	DEVMETHOD(bhnd_bus_get_chipid,		bhnd_generic_get_chipid),
+	DEVMETHOD(bhnd_bus_get_chipid,		bhnd_bus_generic_get_chipid),
 	DEVMETHOD(bhnd_bus_get_probe_order,	bhnd_generic_get_probe_order),
+	DEVMETHOD(bhnd_bus_is_region_valid,	bhnd_generic_is_region_valid),
+	DEVMETHOD(bhnd_bus_is_hostb_device,	bhnd_bus_generic_is_hostb_device),
+	DEVMETHOD(bhnd_bus_is_hw_disabled,	bhnd_bus_generic_is_hw_disabled),
+	DEVMETHOD(bhnd_bus_read_nvram_var,	bhnd_generic_read_nvram_var),
 	DEVMETHOD(bhnd_bus_read_1,		bhnd_read_1),
 	DEVMETHOD(bhnd_bus_read_2,		bhnd_read_2),
 	DEVMETHOD(bhnd_bus_read_4,		bhnd_read_4),
diff --git a/sys/dev/bhnd/bhnd.h b/sys/dev/bhnd/bhnd.h
index 4d9fce80fa2f..7548c8a4dbce 100644
--- a/sys/dev/bhnd/bhnd.h
+++ b/sys/dev/bhnd/bhnd.h
@@ -293,6 +293,36 @@ int				 bhnd_read_chipid(device_t dev,
 void				 bhnd_set_generic_core_desc(device_t dev);
 
 
+
+
+bool				 bhnd_bus_generic_is_hostb_device(device_t dev,
+				     device_t child);
+bool				 bhnd_bus_generic_is_hw_disabled(device_t dev,
+				     device_t child);
+bool				 bhnd_bus_generic_is_region_valid(device_t dev,
+				     device_t child, bhnd_port_type type,
+				     u_int port, u_int region);
+int				 bhnd_bus_generic_read_nvram_var(device_t dev,
+				     device_t child, const char *name,
+				     void *buf, size_t *size);
+const struct bhnd_chipid	*bhnd_bus_generic_get_chipid(device_t dev,
+				     device_t child);
+struct bhnd_resource		*bhnd_bus_generic_alloc_resource (device_t dev,
+				     device_t child, int type, int *rid,
+				     rman_res_t start, rman_res_t end,
+				     rman_res_t count, u_int flags);
+int				 bhnd_bus_generic_release_resource (device_t dev,
+				     device_t child, int type, int rid,
+				     struct bhnd_resource *r);
+int				 bhnd_bus_generic_activate_resource (device_t dev,
+				     device_t child, int type, int rid,
+				     struct bhnd_resource *r);
+int				 bhnd_bus_generic_deactivate_resource (device_t dev,
+				     device_t child, int type, int rid,
+				     struct bhnd_resource *r);
+
+
+
 /**
  * Return true if @p dev is serving as a host bridge for its parent bhnd
  * bus.
diff --git a/sys/dev/bhnd/bhnd_bus_if.m b/sys/dev/bhnd/bhnd_bus_if.m
index b7eb9c5d3d1e..779dd89843a9 100644
--- a/sys/dev/bhnd/bhnd_bus_if.m
+++ b/sys/dev/bhnd/bhnd_bus_if.m
@@ -52,7 +52,25 @@ CODE {
 	static struct bhnd_chipid *
 	bhnd_bus_null_get_chipid(device_t dev, device_t child)
 	{
-		panic("bhnd_get_chipid unimplemented");
+		panic("bhnd_bus_get_chipid unimplemented");
+	}
+	
+	static bool
+	bhnd_bus_null_is_hostb_device(device_t dev, device_t child)
+	{
+		panic("bhnd_bus_is_hostb_device unimplemented");
+	}
+
+	static bool
+	bhnd_bus_null_is_hw_disabled(device_t dev, device_t child)
+	{
+		panic("bhnd_bus_is_hw_disabled unimplemented");
+	}
+	
+	static int
+	bhnd_bus_null_get_probe_order(device_t dev, device_t child)
+	{
+		panic("bhnd_bus_get_probe_order unimplemented");
 	}
 
 	static int
@@ -68,7 +86,7 @@ CODE {
 	{
 		return (ENOENT);
 	}
-	
+
 	static int
 	bhnd_bus_null_get_region_addr(device_t dev, device_t child, 
 	    bhnd_port_type type, u_int port, u_int region, bhnd_addr_t *addr,
@@ -83,6 +101,7 @@ CODE {
 	{
 		return (ENOENT);
 	}
+
 }
 
 /**
@@ -98,7 +117,7 @@ CODE {
 METHOD bool is_hostb_device {
 	device_t dev;
 	device_t child;
-} DEFAULT bhnd_generic_is_hostb_device;
+} DEFAULT bhnd_bus_null_is_hostb_device;
 
 /**
  * Return true if the hardware components required by @p child are unpopulated
@@ -115,7 +134,7 @@ METHOD bool is_hostb_device {
 METHOD bool is_hw_disabled {
 	device_t dev;
 	device_t child;
-} DEFAULT bhnd_generic_is_hw_disabled;
+} DEFAULT bhnd_bus_null_is_hw_disabled;
 
 /**
  * Return the probe (and attach) order for @p child. 
@@ -147,7 +166,7 @@ METHOD bool is_hw_disabled {
 METHOD int get_probe_order {
 	device_t dev;
 	device_t child;
-} DEFAULT bhnd_generic_get_probe_order;
+} DEFAULT bhnd_bus_null_get_probe_order;
 
 /**
  * Return the BHND chip identification for the parent bus.
@@ -205,7 +224,7 @@ METHOD struct bhnd_resource * alloc_resource {
 	rman_res_t end;
 	rman_res_t count;
 	u_int flags;
-} DEFAULT bhnd_generic_alloc_bhnd_resource;
+} DEFAULT bhnd_bus_generic_alloc_resource;
 
 /**
  * Release a bhnd resource.
@@ -219,7 +238,7 @@ METHOD int release_resource {
 	int type;
 	int rid;
 	struct bhnd_resource *res;
-} DEFAULT bhnd_generic_release_bhnd_resource;
+} DEFAULT bhnd_bus_generic_release_resource;
 
 /**
  * Activate a bhnd resource.
@@ -233,7 +252,7 @@ METHOD int activate_resource {
 	int type;
         int rid;
         struct bhnd_resource *r;
-} DEFAULT bhnd_generic_activate_bhnd_resource;
+} DEFAULT bhnd_bus_generic_activate_resource;
 
 /**
  * Deactivate a bhnd resource.
@@ -247,7 +266,7 @@ METHOD int deactivate_resource {
         int type;
 	int rid;
         struct bhnd_resource *r;
-} DEFAULT bhnd_generic_deactivate_bhnd_resource;
+} DEFAULT bhnd_bus_generic_deactivate_resource;
 
 /**
  * Return true if @p region_num is a valid region on @p port_num of
@@ -259,13 +278,13 @@ METHOD int deactivate_resource {
  * @param port_num The port number being queried.
  * @param region_num The region number being queried.
  */
-METHOD u_int is_region_valid {
+METHOD bool is_region_valid {
 	device_t dev;
 	device_t child;
 	bhnd_port_type type;
 	u_int port_num;
 	u_int region_num;
-} DEFAULT bhnd_generic_is_region_valid;
+};
 
 /**
  * Return the number of ports of type @p type attached to @p child.
@@ -278,7 +297,7 @@ METHOD u_int get_port_count {
 	device_t dev;
 	device_t child;
 	bhnd_port_type type;
-}
+};
 
 /**
  * Return the number of memory regions mapped to @p child @p port of
@@ -294,7 +313,7 @@ METHOD u_int get_region_count {
 	device_t child;
 	bhnd_port_type type;
 	u_int port;
-}
+};
 
 /**
  * Return the SYS_RES_MEMORY resource-ID for a port/region pair attached to
diff --git a/sys/dev/bhnd/bhnd_subr.c b/sys/dev/bhnd/bhnd_subr.c
index 3d79845cc9a8..ac1bada33242 100644
--- a/sys/dev/bhnd/bhnd_subr.c
+++ b/sys/dev/bhnd/bhnd_subr.c
@@ -646,3 +646,160 @@ bhnd_set_generic_core_desc(device_t dev)
 		device_set_desc(dev, dev_name);
 	}
 }
+
+/**
+ * Helper function for implementing BHND_BUS_IS_HOSTB_DEVICE().
+ * 
+ * If a parent device is available, this implementation delegates the
+ * request to the BHND_BUS_IS_HOSTB_DEVICE() method on the parent of @p dev.
+ * 
+ * If no parent device is available (i.e. on a the bus root), false
+ * is returned.
+ */
+bool
+bhnd_bus_generic_is_hostb_device(device_t dev, device_t child) {
+	if (device_get_parent(dev) != NULL)
+		return (BHND_BUS_IS_HOSTB_DEVICE(device_get_parent(dev),
+		    child));
+
+	return (false);
+}
+
+/**
+ * Helper function for implementing BHND_BUS_IS_HW_DISABLED().
+ * 
+ * If a parent device is available, this implementation delegates the
+ * request to the BHND_BUS_IS_HW_DISABLED() method on the parent of @p dev.
+ * 
+ * If no parent device is available (i.e. on a the bus root), the hardware
+ * is assumed to be usable and false is returned.
+ */
+bool
+bhnd_bus_generic_is_hw_disabled(device_t dev, device_t child)
+{
+	if (device_get_parent(dev) != NULL)
+		return (BHND_BUS_IS_HW_DISABLED(device_get_parent(dev), child));
+
+	return (false);
+}
+
+/**
+ * Helper function for implementing BHND_BUS_GET_CHIPID().
+ * 
+ * This implementation delegates the request to the BHND_BUS_GET_CHIPID()
+ * method on the parent of @p dev. If no parent exists, the implementation
+ * will panic.
+ */
+const struct bhnd_chipid *
+bhnd_bus_generic_get_chipid(device_t dev, device_t child)
+{
+	if (device_get_parent(dev) != NULL)
+		return (BHND_BUS_GET_CHIPID(device_get_parent(dev), child));
+
+	panic("missing BHND_BUS_GET_CHIPID()");
+}
+
+/**
+ * Helper function for implementing BHND_BUS_ALLOC_RESOURCE().
+ * 
+ * This implementation of BHND_BUS_ALLOC_RESOURCE() delegates allocation
+ * of the underlying resource to BUS_ALLOC_RESOURCE(), and activation
+ * to @p dev's BHND_BUS_ACTIVATE_RESOURCE().
+ */
+struct bhnd_resource *
+bhnd_bus_generic_alloc_resource(device_t dev, device_t child, int type,
+	int *rid, rman_res_t start, rman_res_t end, rman_res_t count,
+	u_int flags)
+{
+	struct bhnd_resource	*br;
+	struct resource		*res;
+	int			 error;
+
+	br = NULL;
+	res = NULL;
+
+	/* Allocate the real bus resource (without activating it) */
+	res = BUS_ALLOC_RESOURCE(dev, child, type, rid, start, end, count,
+	    (flags & ~RF_ACTIVE));
+	if (res == NULL)
+		return (NULL);
+
+	/* Allocate our bhnd resource wrapper. */
+	br = malloc(sizeof(struct bhnd_resource), M_BHND, M_NOWAIT);
+	if (br == NULL)
+		goto failed;
+	
+	br->direct = false;
+	br->res = res;
+
+	/* Attempt activation */
+	if (flags & RF_ACTIVE) {
+		error = BHND_BUS_ACTIVATE_RESOURCE(dev, child, type, *rid, br);
+		if (error)
+			goto failed;
+	}
+
+	return (br);
+	
+failed:
+	if (res != NULL)
+		BUS_RELEASE_RESOURCE(dev, child, type, *rid, res);
+
+	free(br, M_BHND);
+	return (NULL);
+}
+
+/**
+ * Helper function for implementing BHND_BUS_RELEASE_RESOURCE().
+ * 
+ * This implementation of BHND_BUS_RELEASE_RESOURCE() delegates release of
+ * the backing resource to BUS_RELEASE_RESOURCE().
+ */
+int
+bhnd_bus_generic_release_resource(device_t dev, device_t child, int type,
+    int rid, struct bhnd_resource *r)
+{
+	int error;
+
+	if ((error = BUS_RELEASE_RESOURCE(dev, child, type, rid, r->res)))
+		return (error);
+
+	free(r, M_BHND);
+	return (0);
+}
+
+
+/**
+ * Helper function for implementing BHND_BUS_ACTIVATE_RESOURCE().
+ * 
+ * This implementation of BHND_BUS_ACTIVATE_RESOURCE() simply calls the
+ * BHND_BUS_ACTIVATE_RESOURCE() method of the parent of @p dev.
+ */
+int
+bhnd_bus_generic_activate_resource(device_t dev, device_t child, int type,
+    int rid, struct bhnd_resource *r)
+{
+	/* Try to delegate to the parent */
+	if (device_get_parent(dev) != NULL)
+		return (BHND_BUS_ACTIVATE_RESOURCE(device_get_parent(dev),
+		    child, type, rid, r));
+
+	return (EINVAL);
+};
+
+/**
+ * Helper function for implementing BHND_BUS_DEACTIVATE_RESOURCE().
+ * 
+ * This implementation of BHND_BUS_ACTIVATE_RESOURCE() simply calls the
+ * BHND_BUS_ACTIVATE_RESOURCE() method of the parent of @p dev.
+ */
+int
+bhnd_bus_generic_deactivate_resource(device_t dev, device_t child,
+    int type, int rid, struct bhnd_resource *r)
+{
+	if (device_get_parent(dev) != NULL)
+		return (BHND_BUS_DEACTIVATE_RESOURCE(device_get_parent(dev),
+		    child, type, rid, r));
+
+	return (EINVAL);
+};
\ No newline at end of file
diff --git a/sys/dev/bhnd/bhndb/bhndb.c b/sys/dev/bhnd/bhndb/bhndb.c
index f1fc665d8e09..d8943318b529 100644
--- a/sys/dev/bhnd/bhndb/bhndb.c
+++ b/sys/dev/bhnd/bhndb/bhndb.c
@@ -1048,15 +1048,15 @@ bhndb_alloc_resource(device_t dev, device_t child, int type,
 	struct resource			*rv;
 	struct rman			*rm;
 	int				 error;
-	bool				 immed_child, defaults;
+	bool				 passthrough, isdefault;
 
 	sc = device_get_softc(dev);
-	immed_child = (device_get_parent(child) == dev);
-	defaults = (start == 0UL && end == ~0UL);
+	passthrough = (device_get_parent(child) != dev);
+	isdefault = RMAN_IS_DEFAULT_RANGE(start, end);
 	rle = NULL;
 
 	/* Populate defaults */
-	if (immed_child && defaults) {
+	if (!passthrough && isdefault) {
 		/* Fetch the resource list entry. */
 		rle = resource_list_find(BUS_GET_RESOURCE_LIST(dev, child),
 		    type, *rid);
@@ -1083,7 +1083,7 @@ bhndb_alloc_resource(device_t dev, device_t child, int type,
 	}
 
 	/* Validate resource addresses */
-	if (start > end || end < start || count > ((end - start) + 1))
+	if (start > end || count > ((end - start) + 1))
 		return (NULL);
 	
 	/* Fetch the resource manager */
@@ -1512,62 +1512,6 @@ bhndb_get_resource_list(device_t dev, device_t child)
 }
 
 /**
- * Default bhndb(4) implementation of BHND_BUS_ALLOC_RESOURCE().
- */
-static struct bhnd_resource *
-bhndb_alloc_bhnd_resource(device_t dev, device_t child, int type,
-     int *rid, rman_res_t start, rman_res_t end, rman_res_t count, u_int flags)
-{
-	struct bhndb_softc	*sc;
-	struct bhnd_resource	*br;
-
-	sc = device_get_softc(dev);
-
-	/* Allocate resource wrapper */
-	br = malloc(sizeof(struct bhnd_resource), M_BHND, M_NOWAIT|M_ZERO);
-	if (br == NULL)
-		return (NULL);
-
-	/* Configure */
-	br->direct = false;
-	br->res = bus_alloc_resource(child, type, rid, start, end, count,
-	    flags & ~RF_ACTIVE);
-	if (br->res == NULL)
-		goto failed;
-	
-
-	if (flags & RF_ACTIVE) {
-		if (bhnd_activate_resource(child, type, *rid, br))
-			goto failed;
-	}
-
-	return (br);
-
-failed:
-	if (br->res != NULL)
-		bus_release_resource(child, type, *rid, br->res);
-
-	free(br, M_BHND);
-	return (NULL);
-}
-
-/**
- * Default bhndb(4) implementation of BHND_BUS_RELEASE_RESOURCE().
- */
-static int
-bhndb_release_bhnd_resource(device_t dev, device_t child,
-    int type, int rid, struct bhnd_resource *r)
-{
-	int error;
-
-	if ((error = bus_release_resource(child, type, rid, r->res)))
-		return (error);
-
-	free(r, M_BHND);
-	return (0);
-}
-
-/**
  * Default bhndb(4) implementation of BHND_BUS_ACTIVATE_RESOURCE().
  *
  * For BHNDB_ADDRSPACE_NATIVE children, all resources may be assumed to
@@ -1983,8 +1927,6 @@ static device_method_t bhndb_methods[] = {
 	DEVMETHOD(bhnd_bus_is_hw_disabled,	bhndb_is_hw_disabled),
 	DEVMETHOD(bhnd_bus_is_hostb_device,	bhndb_is_hostb_device),
 	DEVMETHOD(bhnd_bus_get_chipid,		bhndb_get_chipid),
-	DEVMETHOD(bhnd_bus_alloc_resource,	bhndb_alloc_bhnd_resource),
-	DEVMETHOD(bhnd_bus_release_resource,	bhndb_release_bhnd_resource),
 	DEVMETHOD(bhnd_bus_activate_resource,	bhndb_activate_bhnd_resource),
 	DEVMETHOD(bhnd_bus_activate_resource,	bhndb_deactivate_bhnd_resource),
 	DEVMETHOD(bhnd_bus_read_1,		bhndb_bus_read_1),
diff --git a/sys/dev/bhnd/bhndvar.h b/sys/dev/bhnd/bhndvar.h
index 4b18ba40b0eb..6dcfc4e2c278 100644
--- a/sys/dev/bhnd/bhndvar.h
+++ b/sys/dev/bhnd/bhndvar.h
@@ -70,37 +70,5 @@ int			 bhnd_generic_suspend_child(device_t dev,
 			     device_t child);
 int			 bhnd_generic_resume_child(device_t dev,
 			     device_t child);
-	
-bool			 bhnd_generic_is_hostb_device(device_t dev,
-			     device_t child);
-bool			 bhnd_generic_is_hw_disabled(device_t dev,
-			     device_t child);
-bool			 bhnd_generic_is_region_valid(device_t dev,
-			     device_t child, bhnd_port_type type, u_int port,
-			     u_int region);
-
-int			 bhnd_generic_read_nvram_var(device_t dev,
-			     device_t child, const char *name, void *buf,
-			     size_t *size);
-
-const struct bhnd_chipid *bhnd_generic_get_chipid(device_t dev, device_t child);
-
-struct bhnd_resource	*bhnd_generic_alloc_bhnd_resource (device_t dev,
-			     device_t child, int type, int *rid,
-			     rman_res_t start, rman_res_t end, rman_res_t count,
-			     u_int flags);
-
-int			 bhnd_generic_release_bhnd_resource (device_t dev,
-			     device_t child, int type, int rid,
-			     struct bhnd_resource *r);
-
-int			 bhnd_generic_activate_bhnd_resource (device_t dev,
-			     device_t child, int type, int rid,
-			     struct bhnd_resource *r);
-
-int			 bhnd_generic_deactivate_bhnd_resource (device_t dev,
-			     device_t child, int type, int rid,
-			     struct bhnd_resource *r);
-
 
 #endif /* _BHND_BHNDVAR_H_ */