Implement devctl(8) command 'reset', using DEV_RESET /dev/devctl2 ioctl.

Reviewed by:	imp (previous version), jhb (previous version)
Sponsored by:	Mellanox Technologies
MFC after:	2 weeks
Differential revision:	https://reviews.freebsd.org/D19646

2 files changed, 70 insertions, 2 deletions

diff --git a/usr.sbin/devctl/devctl.8 b/usr.sbin/devctl/devctl.8
index 481a99ec0dc6..9fc3e69b1183 100644
--- a/usr.sbin/devctl/devctl.8
+++ b/usr.sbin/devctl/devctl.8
@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd August 29, 2016
+.Dd April 4, 2019
 .Dt DEVCTL 8
 .Os
 .Sh NAME
@@ -66,6 +66,10 @@
 .Cm delete
 .Op Fl f
 .Ar device
+.Nm
+.Cm reset
+.Op Fl d
+.Ar device
 .Sh DESCRIPTION
 The
 .Nm
@@ -166,7 +170,35 @@ the device will be deleted even if it is physically present.
 This command should be used with care as a device that is deleted but present
 can no longer be used unless the parent bus device rediscovers the device via
 a rescan request.
+.It Xo Cm reset
+.Op Fl d
+.Ar device
+.Xc
+Reset the device, using bus-specific reset method.
+Drivers for the devices being reset are suspended around the reset.
+If the
+.Fl d
+option is specified, drivers are detached instead.
+.Pp
+Currently, resets are implemented for PCIe buses and PCI devices.
+For PCIe bus, the link is disabled and then re-trained, causing all
+children of the bus to reset.
+Use
+.Fl p
+option of
+.Xr devinfo 8
+tool to report parent bus for the device.
+For PCI device, if Function-Level Reset is implemented by it, FLR is
+tried first; if failed or not implemented, power reset is tried.
+.Pp
+If you have detached or suspended a child device explicitly and then
+do a reset, the child device will end up attached.
 .El
+.Sh BUGS
+Currently there is no administrative flag to prevent re-attach or resume
+of the manually detached or suspended devices after reset.
+Similarly, there is no flag to prevent un-suspending of the the manually
+suspended devices after system resume.
 .Sh SEE ALSO
 .Xr devctl 3 ,
 .Xr devinfo 8
diff --git a/usr.sbin/devctl/devctl.c b/usr.sbin/devctl/devctl.c
index 20c332d89409..32fbb64ef185 100644
--- a/usr.sbin/devctl/devctl.c
+++ b/usr.sbin/devctl/devctl.c
@@ -82,7 +82,9 @@ usage(void)
 	    "       devctl rescan device\n"
 	    "       devctl delete [-f] device\n"
 	    "       devctl freeze\n"
-	    "       devctl thaw\n");
+	    "       devctl thaw\n"
+	    "       devctl reset [-d] device\n"
+	    );
 	exit(1);
 }
 
@@ -384,6 +386,40 @@ thaw(int ac, char **av __unused)
 }
 DEVCTL_COMMAND(top, thaw, thaw);
 
+static void
+reset_usage(void)
+{
+
+	fprintf(stderr, "usage: devctl reset [-d] device\n");
+	exit(1);
+}
+
+static int
+reset(int ac, char **av)
+{
+	bool detach;
+	int ch;
+
+	detach = false;
+	while ((ch = getopt(ac, av, "d")) != -1)
+		switch (ch) {
+		case 'd':
+			detach = true;
+			break;
+		default:
+			reset_usage();
+		}
+	ac -= optind;
+	av += optind;
+
+	if (ac != 1)
+		reset_usage();
+	if (devctl_reset(av[0], detach) < 0)
+		err(1, "Failed to reset %s", av[0]);
+	return (0);
+}
+DEVCTL_COMMAND(top, reset, reset);
+
 int
 main(int ac, char *av[])
 {