Add a new rescan method to the bus interface.

The BUS_RESCAN() method rescans a single bus device checking for devices
that have been added or removed from the bus.  A new 'rescan' command is
added to devctl(8) to trigger a rescan.

Differential Revision:	https://reviews.freebsd.org/D6016

3 files changed, 28 insertions, 2 deletions

diff --git a/lib/libdevctl/devctl.3 b/lib/libdevctl/devctl.3
index b2734cf..7d8ddba 100644
--- a/lib/libdevctl/devctl.3
+++ b/lib/libdevctl/devctl.3
@@ -25,7 +25,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd February 2, 2016
+.Dd April 27, 2016
 .Dt DEVCTL 3
 .Os
 .Sh NAME
@@ -34,6 +34,7 @@
 .Nm devctl_detach ,
 .Nm devctl_disable ,
 .Nm devctl_enable ,
+.Nm devctl_rescan ,
 .Nm devctl_resume ,
 .Nm devctl_set_driver ,
 .Nm devctl_suspend
@@ -51,6 +52,8 @@
 .Ft int
 .Fn devctl_enable "const char *device"
 .Ft int
+.Fn devctl_rescan "const char *device"
+.Ft int
 .Fn devctl_resume "const char *device"
 .Ft int
 .Fn devctl_set_driver "const char *device" "const char *driver" "bool force"
@@ -149,9 +152,14 @@ If the device is already attached and
 is true,
 the device will be detached from its current device driver before it is
 attached to the new device driver.
+.Pp
+The
+.Fn devctl_rescan
+function rescans a bus device checking for devices that have been added or
+removed.
 .Sh RETURN VALUES
 .Rv -std devctl_attach devctl_detach devctl_disable devctl_enable \
-devctl_suspend devctl_resume devctl_set_driver
+devctl_suspend devctl_rescan devctl_resume devctl_set_driver
 .Sh ERRORS
 In addition to specific errors noted below,
 all of the
@@ -280,6 +288,16 @@ The device is disabled.
 .It Bq Er ENXIO
 The new device driver failed to attach.
 .El
+.Pp
+The
+.Fn devctl_rescan
+function may fail if:
+.Bl -tag -width Er
+.It Bq Er ENXIO
+The device is not attached to a driver.
+.It Bq Er ENXIO
+The bus driver does not support rescanning.
+.El
 .Sh SEE ALSO
 .Xr devinfo 3 ,
 .Xr devstat 3 ,
diff --git a/lib/libdevctl/devctl.c b/lib/libdevctl/devctl.c
index 7be431e..33c891b 100644
--- a/lib/libdevctl/devctl.c
+++ b/lib/libdevctl/devctl.c
@@ -122,3 +122,10 @@ devctl_set_driver(const char *device, const char *driver, bool force)
 		req.dr_flags |= DEVF_SET_DRIVER_DETACH;
 	return (devctl_request(DEV_SET_DRIVER, &req));
 }
+
+int
+devctl_rescan(const char *device)
+{
+
+	return (devctl_simple_request(DEV_RESCAN, device, 0));
+}
diff --git a/lib/libdevctl/devctl.h b/lib/libdevctl/devctl.h
index f773b11..40c64c1 100644
--- a/lib/libdevctl/devctl.h
+++ b/lib/libdevctl/devctl.h
@@ -38,5 +38,6 @@ int	devctl_disable(const char *device, bool force_detach);
 int	devctl_suspend(const char *device);
 int	devctl_resume(const char *device);
 int	devctl_set_driver(const char *device, const char *driver, bool force);
+int	devctl_rescan(const char *device);
 
 #endif /* !__DEVCTL_H__ */