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Documentation: usb: MASS STORAGE function testing

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Summary of how to test MASS STORAGE function of USB gadget.

Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
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Andrzej Pietrasiewicz 2014-12-16 14:56:32 +01:00 committed by Felipe Balbi
parent ec91aff763
commit cdbe287d27
1 changed files with 54 additions and 0 deletions
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Documentation/usb/gadget-testing.txt
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@ -8,6 +8,7 @@ provided by gadgets.
5. FFS function 5. FFS function
6. HID function 6. HID function
7. LOOPBACK function 7. LOOPBACK function
8. MASS STORAGE function
1. ACM function 1. ACM function
@ -228,3 +229,56 @@ device: run the gadget
host: test-usb host: test-usb
http://www.linux-usb.org/usbtest/testusb.c http://www.linux-usb.org/usbtest/testusb.c
8. MASS STORAGE function
========================
The function is provided by usb_f_mass_storage.ko module.
Function-specific configfs interface
------------------------------------
The function name to use when creating the function directory is "mass_storage".
The MASS STORAGE function provides these attributes in its directory:
files:
stall - Set to permit function to halt bulk endpoints.
Disabled on some USB devices known not to work
correctly. You should set it to true.
num_buffers - Number of pipeline buffers. Valid numbers
are 2..4. Available only if
CONFIG_USB_GADGET_DEBUG_FILES is set.
and a default lun.0 directory corresponding to SCSI LUN #0.
A new lun can be added with mkdir:
$ mkdir functions/mass_storage.0/partition.5
Lun numbering does not have to be continuous, except for lun #0 which is
created by default. A maximum of 8 luns can be specified and they all must be
named following the <name>.<number> scheme. The numbers can be 0..8.
Probably a good convention is to name the luns "lun.<number>",
although it is not mandatory.
In each lun directory there are the following attribute files:
file - The path to the backing file for the LUN.
Required if LUN is not marked as removable.
ro - Flag specifying access to the LUN shall be
read-only. This is implied if CD-ROM emulation
is enabled as well as when it was impossible
to open "filename" in R/W mode.
removable - Flag specifying that LUN shall be indicated as
being removable.
cdrom - Flag specifying that LUN shall be reported as
being a CD-ROM.
nofua - Flag specifying that FUA flag
in SCSI WRITE(10,12)
Testing the MASS STORAGE function
---------------------------------
device: connect the gadget, enable it
host: dmesg, see the USB drives appear (if system configured to automatically
mount)