Add a new device control utility for new-bus devices called devctl. This

allows the user to request administrative changes to individual devices
such as attach or detaching drivers or disabling and re-enabling devices.
- Add a new /dev/devctl2 character device which uses ioctls for device
  requests.  The ioctls use a common 'struct devreq' which is somewhat
  similar to 'struct ifreq'.
- The ioctls identify the device to operate on via a string.  This
  string can either by the device's name, or it can be a bus-specific
  address.  (For unattached devices, a bus address is the only way to
  locate a device.)  Bus drivers register an eventhandler to claim
  unrecognized device names that the driver recognizes as a valid address.
  Two buses currently support addresses: ACPI recognizes any device
  in the ACPI namespace via its full path starting with "\" and
  the PCI bus driver recognizes an address specification of
  'pci[<domain>:]<bus>:<slot>:<func>' (identical to the PCI selector
  strings supported by pciconf).
- To make it easier to cut and paste, change the PnP location string
  in the PCI bus driver to output a full PCI selector string rather
  than 'slot=<slot> function=<func>'.
- Add a devctl(3) interface in libdevctl which provides a wrapper around
  the ioctls and is the preferred interface for other userland code.
- Add a devctl(8) program which is a simple wrapper around the requests
  supported by devctl(3).
- Add a device_is_suspended() function to check DF_SUSPENDED.
- Add a resource_unset_value() function that can be used to remove a
  hint from the kernel environment.  This is used to clear a
  hint.<driver>.<unit>.disabled hint when re-enabling a boot-time
  disabled device.

Reviewed by:	imp (parts)
Requested by:	imp (changing PCI location string)
Relnotes:	yes

1 files changed, 124 insertions, 0 deletions

diff --git a/lib/libdevctl/devctl.c b/lib/libdevctl/devctl.c
new file mode 100644
index 0000000..7be431e
--- /dev/null
+++ b/lib/libdevctl/devctl.c
@@ -0,0 +1,124 @@
+/*-
+ * Copyright (c) 2014 John Baldwin <jhb@FreeBSD.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/types.h>
+#include <sys/bus.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <string.h>
+#include "devctl.h"
+
+static int
+devctl_request(u_long cmd, struct devreq *req)
+{
+	static int devctl2_fd = -1;
+
+	if (devctl2_fd == -1) {
+		devctl2_fd = open("/dev/devctl2", O_RDONLY);
+		if (devctl2_fd == -1)
+			return (-1);
+	}
+	return (ioctl(devctl2_fd, cmd, req));
+}
+
+static int
+devctl_simple_request(u_long cmd, const char *name, int flags)
+{
+	struct devreq req;
+
+	memset(&req, 0, sizeof(req));
+	if (strlcpy(req.dr_name, name, sizeof(req.dr_name)) >=
+	    sizeof(req.dr_name)) {
+		errno = EINVAL;
+		return (-1);
+	}
+	req.dr_flags = flags;
+	return (devctl_request(cmd, &req));
+}
+
+int
+devctl_attach(const char *device)
+{
+
+	return (devctl_simple_request(DEV_ATTACH, device, 0));
+}
+
+int
+devctl_detach(const char *device, bool force)
+{
+
+	return (devctl_simple_request(DEV_DETACH, device, force ?
+	    DEVF_FORCE_DETACH : 0));
+}
+
+int
+devctl_enable(const char *device)
+{
+
+	return (devctl_simple_request(DEV_ENABLE, device, 0));
+}
+
+int
+devctl_disable(const char *device, bool force_detach)
+{
+
+	return (devctl_simple_request(DEV_DISABLE, device, force_detach ?
+	    DEVF_FORCE_DETACH : 0));
+}
+
+int
+devctl_suspend(const char *device)
+{
+
+	return (devctl_simple_request(DEV_SUSPEND, device, 0));
+}
+
+int
+devctl_resume(const char *device)
+{
+
+	return (devctl_simple_request(DEV_RESUME, device, 0));
+}
+
+int
+devctl_set_driver(const char *device, const char *driver, bool force)
+{
+	struct devreq req;
+
+	memset(&req, 0, sizeof(req));
+	if (strlcpy(req.dr_name, device, sizeof(req.dr_name)) >=
+	    sizeof(req.dr_name)) {
+		errno = EINVAL;
+		return (-1);
+	}
+	req.dr_data = __DECONST(char *, driver);
+	if (force)
+		req.dr_flags |= DEVF_SET_DRIVER_DETACH;
+	return (devctl_request(DEV_SET_DRIVER, &req));
+}