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Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/usb/gadget-testing.txt | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/Documentation/usb/gadget-testing.txt b/Documentation/usb/gadget-testing.txt index b13491d..01b9ffe 100644 --- a/Documentation/usb/gadget-testing.txt +++ b/Documentation/usb/gadget-testing.txt @@ -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) |