Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit cdbe287d authored by Andrzej Pietrasiewicz's avatar Andrzej Pietrasiewicz Committed by Felipe Balbi
Browse files

Documentation: usb: MASS STORAGE function testing 



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

Signed-off-by: default avatarAndrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: default avatarFelipe Balbi <balbi@ti.com>
parent ec91aff7

Documentation/usb/gadget-testing.txt

+54 −0
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ provided by gadgets. 
5. FFS function

6. HID function

7. LOOPBACK function

8. MASS STORAGE function





1. ACM function
@@ -228,3 +229,56 @@ device: run the gadget 
host: test-usb



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)