xref: /freebsd/share/man/man4/cfumass.4 (revision d6eb98610fa65663bf0df4574b7cb2c5c4ffda71)
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4.\" This software was developed by Edward Tomasz Napierala under sponsorship
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28.\" $FreeBSD$
29.Dd April 21, 2018
30.Dt CFUMASS 4
31.Os
32.Sh NAME
33.Nm cfumass
34.Nd USB device side support for Mass Storage Class Transport
35.Sh SYNOPSIS
36This driver can be compiled into the kernel by placing these lines in
37the kernel configuration file:
38.Bd -ragged -offset indent
39.Cd "device usb"
40.Cd "device usb_template"
41.Cd "device ctl"
42.Cd "device cfumass"
43.Ed
44.Pp
45The driver module can also be loaded at boot by adding this line to
46.Xr loader.conf 5 :
47.Bd -literal -offset indent
48cfumass_load="YES"
49.Ed
50.Sh DESCRIPTION
51The
52.Nm
53driver provides device side support for emulating an USB mass storage
54device compliant with the USB Mass Storage Class Bulk-Only (BBB) Transport
55specification, implemented as a
56.Xr ctl 4
57frontend driver.
58.Pp
59To use
60.Nm :
61.Bl -bullet
62.It
63.Xr cfumass 4
64must be loaded as a module or compiled into the kernel.
65.It
66The USB Mass Storage template must be chosen by setting the
67.Va hw.usb.template
68sysctl to 0.
69.It
70The USB OTG port must be working in USB device-side mode.
71This happens automatically upon connection to a USB host.
72.It
73There must be a
74.Xr ctl 4
75LUN configured for the
76.Pa cfumass
77port.
78.El
79.Pp
80Upon loading, the driver creates a
81.Xr ctl 4
82port named
83.Pa cfumass ,
84presenting the first LUN mapped for that port - usually LUN 0 - to
85the USB host.
86See
87.Xr ctl.conf 5
88and
89.Xr ctld 8
90for details on configuring the LUN.
91See the
92.Cm cfumass_enable
93and
94.Cm cfumass_dir
95.Xr rc 8
96variables in
97.Xr rc.conf 5
98for an automated way to configure it at boot.
99.Sh SYSCTL VARIABLES
100These variables are available as both
101.Xr sysctl 8
102variables and
103.Xr loader 8
104tunables:
105.Bl -tag -width indent
106.It Va hw.usb.cfumass.debug
107Verbosity level for log messages from the
108.Nm
109driver.
110Set to 0 to disable logging or 1 to warn about potential problems.
111Larger values enable debugging output.
112Defaults to 1.
113.It Va hw.usb.cfumass.ignore_stop
114Ignore START STOP UNIT SCSI commands with START and LOEJ bits cleared.
115Some initiators send that command to stop the target when the user
116attempts to gracefully eject the drive, but fail to start it when the
117drive is reconnected.
118Set to 0 to handle the command in a standards-compliant way,
1191 to ignore it and log a warning, or 2 to ignore it silently.
120Defaults to 1.
121.It Va hw.usb.cfumass.max_lun
122Max LUN number to report to the initiator (USB host).
123Must be between 0 and 15.
124Some initiators incorrectly handle values larger than 0.
125Defaults to 0.
126.El
127.Sh SEE ALSO
128.Xr ctl 4 ,
129.Xr umass 4 ,
130.Xr usb 4 ,
131.Xr usb_template 4 ,
132.Xr ctl.conf 5 ,
133.Xr ctld 8
134.Sh HISTORY
135The
136.Nm
137driver first appeared in
138.Fx 11.1 .
139.Sh AUTHORS
140The
141.Nm
142driver was developed by
143.An Edward Tomasz Napierala Aq Mt trasz@FreeBSD.org
144under sponsorship from the FreeBSD Foundation.
145