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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
commit | ace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch) | |
tree | b2d64bc10158fdd5497876388cd68142ca374ed3 /Documentation/usb/gadget-testing.rst | |
parent | Initial commit. (diff) | |
download | linux-upstream/6.6.15.tar.xz linux-upstream/6.6.15.zip |
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'Documentation/usb/gadget-testing.rst')
-rw-r--r-- | Documentation/usb/gadget-testing.rst | 1121 |
1 files changed, 1121 insertions, 0 deletions
diff --git a/Documentation/usb/gadget-testing.rst b/Documentation/usb/gadget-testing.rst new file mode 100644 index 0000000000..394cd226bf --- /dev/null +++ b/Documentation/usb/gadget-testing.rst @@ -0,0 +1,1121 @@ +============== +Gadget Testing +============== + +This file summarizes information on basic testing of USB functions +provided by gadgets. + +.. contents + + 1. ACM function + 2. ECM function + 3. ECM subset function + 4. EEM function + 5. FFS function + 6. HID function + 7. LOOPBACK function + 8. MASS STORAGE function + 9. MIDI function + 10. NCM function + 11. OBEX function + 12. PHONET function + 13. RNDIS function + 14. SERIAL function + 15. SOURCESINK function + 16. UAC1 function (legacy implementation) + 17. UAC2 function + 18. UVC function + 19. PRINTER function + 20. UAC1 function (new API) + 21. MIDI2 function + + +1. ACM function +=============== + +The function is provided by usb_f_acm.ko module. + +Function-specific configfs interface +------------------------------------ + +The function name to use when creating the function directory is "acm". +The ACM function provides just one attribute in its function directory: + + port_num + +The attribute is read-only. + +There can be at most 4 ACM/generic serial/OBEX ports in the system. + + +Testing the ACM function +------------------------ + +On the host:: + + cat > /dev/ttyACM<X> + +On the device:: + + cat /dev/ttyGS<Y> + +then the other way round + +On the device:: + + cat > /dev/ttyGS<Y> + +On the host:: + + cat /dev/ttyACM<X> + +2. ECM function +=============== + +The function is provided by usb_f_ecm.ko module. + +Function-specific configfs interface +------------------------------------ + +The function name to use when creating the function directory is "ecm". +The ECM function provides these attributes in its function directory: + + =============== ================================================== + ifname network device interface name associated with this + function instance + qmult queue length multiplier for high and super speed + host_addr MAC address of host's end of this + Ethernet over USB link + dev_addr MAC address of device's end of this + Ethernet over USB link + =============== ================================================== + +and after creating the functions/ecm.<instance name> they contain default +values: qmult is 5, dev_addr and host_addr are randomly selected. +The ifname can be written to if the function is not bound. A write must be an +interface pattern such as "usb%d", which will cause the net core to choose the +next free usbX interface. By default, it is set to "usb%d". + +Testing the ECM function +------------------------ + +Configure IP addresses of the device and the host. Then: + +On the device:: + + ping <host's IP> + +On the host:: + + ping <device's IP> + +3. ECM subset function +====================== + +The function is provided by usb_f_ecm_subset.ko module. + +Function-specific configfs interface +------------------------------------ + +The function name to use when creating the function directory is "geth". +The ECM subset function provides these attributes in its function directory: + + =============== ================================================== + ifname network device interface name associated with this + function instance + qmult queue length multiplier for high and super speed + host_addr MAC address of host's end of this + Ethernet over USB link + dev_addr MAC address of device's end of this + Ethernet over USB link + =============== ================================================== + +and after creating the functions/ecm.<instance name> they contain default +values: qmult is 5, dev_addr and host_addr are randomly selected. +The ifname can be written to if the function is not bound. A write must be an +interface pattern such as "usb%d", which will cause the net core to choose the +next free usbX interface. By default, it is set to "usb%d". + +Testing the ECM subset function +------------------------------- + +Configure IP addresses of the device and the host. Then: + +On the device:: + + ping <host's IP> + +On the host:: + + ping <device's IP> + +4. EEM function +=============== + +The function is provided by usb_f_eem.ko module. + +Function-specific configfs interface +------------------------------------ + +The function name to use when creating the function directory is "eem". +The EEM function provides these attributes in its function directory: + + =============== ================================================== + ifname network device interface name associated with this + function instance + qmult queue length multiplier for high and super speed + host_addr MAC address of host's end of this + Ethernet over USB link + dev_addr MAC address of device's end of this + Ethernet over USB link + =============== ================================================== + +and after creating the functions/eem.<instance name> they contain default +values: qmult is 5, dev_addr and host_addr are randomly selected. +The ifname can be written to if the function is not bound. A write must be an +interface pattern such as "usb%d", which will cause the net core to choose the +next free usbX interface. By default, it is set to "usb%d". + +Testing the EEM function +------------------------ + +Configure IP addresses of the device and the host. Then: + +On the device:: + + ping <host's IP> + +On the host:: + + ping <device's IP> + +5. FFS function +=============== + +The function is provided by usb_f_fs.ko module. + +Function-specific configfs interface +------------------------------------ + +The function name to use when creating the function directory is "ffs". +The function directory is intentionally empty and not modifiable. + +After creating the directory there is a new instance (a "device") of FunctionFS +available in the system. Once a "device" is available, the user should follow +the standard procedure for using FunctionFS (mount it, run the userspace +process which implements the function proper). The gadget should be enabled +by writing a suitable string to usb_gadget/<gadget>/UDC. + +Testing the FFS function +------------------------ + +On the device: start the function's userspace daemon, enable the gadget + +On the host: use the USB function provided by the device + +6. HID function +=============== + +The function is provided by usb_f_hid.ko module. + +Function-specific configfs interface +------------------------------------ + +The function name to use when creating the function directory is "hid". +The HID function provides these attributes in its function directory: + + =============== =========================================== + protocol HID protocol to use + report_desc data to be used in HID reports, except data + passed with /dev/hidg<X> + report_length HID report length + subclass HID subclass to use + =============== =========================================== + +For a keyboard the protocol and the subclass are 1, the report_length is 8, +while the report_desc is:: + + $ hd my_report_desc + 00000000 05 01 09 06 a1 01 05 07 19 e0 29 e7 15 00 25 01 |..........)...%.| + 00000010 75 01 95 08 81 02 95 01 75 08 81 03 95 05 75 01 |u.......u.....u.| + 00000020 05 08 19 01 29 05 91 02 95 01 75 03 91 03 95 06 |....).....u.....| + 00000030 75 08 15 00 25 65 05 07 19 00 29 65 81 00 c0 |u...%e....)e...| + 0000003f + +Such a sequence of bytes can be stored to the attribute with echo:: + + $ echo -ne \\x05\\x01\\x09\\x06\\xa1..... + +Testing the HID function +------------------------ + +Device: + +- create the gadget +- connect the gadget to a host, preferably not the one used + to control the gadget +- run a program which writes to /dev/hidg<N>, e.g. + a userspace program found in Documentation/usb/gadget_hid.rst:: + + $ ./hid_gadget_test /dev/hidg0 keyboard + +Host: + +- observe the keystrokes from the gadget + +7. LOOPBACK function +==================== + +The function is provided by usb_f_ss_lb.ko module. + +Function-specific configfs interface +------------------------------------ + +The function name to use when creating the function directory is "Loopback". +The LOOPBACK function provides these attributes in its function directory: + + =============== ======================= + qlen depth of loopback queue + bulk_buflen buffer length + =============== ======================= + +Testing the LOOPBACK function +----------------------------- + +device: run the gadget + +host: test-usb (tools/usb/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) + forced_eject This write-only file is useful only when + the function is active. It causes the backing + file to be forcibly detached from the LUN, + regardless of whether the host has allowed it. + Any non-zero number of bytes written will + result in ejection. + =============== ============================================== + +Testing the MASS STORAGE function +--------------------------------- + +device: connect the gadget, enable it +host: dmesg, see the USB drives appear (if system configured to automatically +mount) + +9. MIDI function +================ + +The function is provided by usb_f_midi.ko module. + +Function-specific configfs interface +------------------------------------ + +The function name to use when creating the function directory is "midi". +The MIDI function provides these attributes in its function directory: + + =============== ==================================== + buflen MIDI buffer length + id ID string for the USB MIDI adapter + in_ports number of MIDI input ports + index index value for the USB MIDI adapter + out_ports number of MIDI output ports + qlen USB read request queue length + =============== ==================================== + +Testing the MIDI function +------------------------- + +There are two cases: playing a mid from the gadget to +the host and playing a mid from the host to the gadget. + +1) Playing a mid from the gadget to the host: + +host:: + + $ arecordmidi -l + Port Client name Port name + 14:0 Midi Through Midi Through Port-0 + 24:0 MIDI Gadget MIDI Gadget MIDI 1 + $ arecordmidi -p 24:0 from_gadget.mid + +gadget:: + + $ aplaymidi -l + Port Client name Port name + 20:0 f_midi f_midi + + $ aplaymidi -p 20:0 to_host.mid + +2) Playing a mid from the host to the gadget + +gadget:: + + $ arecordmidi -l + Port Client name Port name + 20:0 f_midi f_midi + + $ arecordmidi -p 20:0 from_host.mid + +host:: + + $ aplaymidi -l + Port Client name Port name + 14:0 Midi Through Midi Through Port-0 + 24:0 MIDI Gadget MIDI Gadget MIDI 1 + + $ aplaymidi -p24:0 to_gadget.mid + +The from_gadget.mid should sound identical to the to_host.mid. + +The from_host.id should sound identical to the to_gadget.mid. + +MIDI files can be played to speakers/headphones with e.g. timidity installed:: + + $ aplaymidi -l + Port Client name Port name + 14:0 Midi Through Midi Through Port-0 + 24:0 MIDI Gadget MIDI Gadget MIDI 1 + 128:0 TiMidity TiMidity port 0 + 128:1 TiMidity TiMidity port 1 + 128:2 TiMidity TiMidity port 2 + 128:3 TiMidity TiMidity port 3 + + $ aplaymidi -p 128:0 file.mid + +MIDI ports can be logically connected using the aconnect utility, e.g.:: + + $ aconnect 24:0 128:0 # try it on the host + +After the gadget's MIDI port is connected to timidity's MIDI port, +whatever is played at the gadget side with aplaymidi -l is audible +in host's speakers/headphones. + +10. NCM function +================ + +The function is provided by usb_f_ncm.ko module. + +Function-specific configfs interface +------------------------------------ + +The function name to use when creating the function directory is "ncm". +The NCM function provides these attributes in its function directory: + + =============== ================================================== + ifname network device interface name associated with this + function instance + qmult queue length multiplier for high and super speed + host_addr MAC address of host's end of this + Ethernet over USB link + dev_addr MAC address of device's end of this + Ethernet over USB link + =============== ================================================== + +and after creating the functions/ncm.<instance name> they contain default +values: qmult is 5, dev_addr and host_addr are randomly selected. +The ifname can be written to if the function is not bound. A write must be an +interface pattern such as "usb%d", which will cause the net core to choose the +next free usbX interface. By default, it is set to "usb%d". + +Testing the NCM function +------------------------ + +Configure IP addresses of the device and the host. Then: + +On the device:: + + ping <host's IP> + +On the host:: + + ping <device's IP> + +11. OBEX function +================= + +The function is provided by usb_f_obex.ko module. + +Function-specific configfs interface +------------------------------------ + +The function name to use when creating the function directory is "obex". +The OBEX function provides just one attribute in its function directory: + + port_num + +The attribute is read-only. + +There can be at most 4 ACM/generic serial/OBEX ports in the system. + +Testing the OBEX function +------------------------- + +On device:: + + seriald -f /dev/ttyGS<Y> -s 1024 + +On host:: + + serialc -v <vendorID> -p <productID> -i<interface#> -a1 -s1024 \ + -t<out endpoint addr> -r<in endpoint addr> + +where seriald and serialc are Felipe's utilities found here: + + https://github.com/felipebalbi/usb-tools.git master + +12. PHONET function +=================== + +The function is provided by usb_f_phonet.ko module. + +Function-specific configfs interface +------------------------------------ + +The function name to use when creating the function directory is "phonet". +The PHONET function provides just one attribute in its function directory: + + =============== ================================================== + ifname network device interface name associated with this + function instance + =============== ================================================== + +Testing the PHONET function +--------------------------- + +It is not possible to test the SOCK_STREAM protocol without a specific piece +of hardware, so only SOCK_DGRAM has been tested. For the latter to work, +in the past I had to apply the patch mentioned here: + +http://www.spinics.net/lists/linux-usb/msg85689.html + +These tools are required: + +git://git.gitorious.org/meego-cellular/phonet-utils.git + +On the host:: + + $ ./phonet -a 0x10 -i usbpn0 + $ ./pnroute add 0x6c usbpn0 + $./pnroute add 0x10 usbpn0 + $ ifconfig usbpn0 up + +On the device:: + + $ ./phonet -a 0x6c -i upnlink0 + $ ./pnroute add 0x10 upnlink0 + $ ifconfig upnlink0 up + +Then a test program can be used:: + + http://www.spinics.net/lists/linux-usb/msg85690.html + +On the device:: + + $ ./pnxmit -a 0x6c -r + +On the host:: + + $ ./pnxmit -a 0x10 -s 0x6c + +As a result some data should be sent from host to device. +Then the other way round: + +On the host:: + + $ ./pnxmit -a 0x10 -r + +On the device:: + + $ ./pnxmit -a 0x6c -s 0x10 + +13. RNDIS function +================== + +The function is provided by usb_f_rndis.ko module. + +Function-specific configfs interface +------------------------------------ + +The function name to use when creating the function directory is "rndis". +The RNDIS function provides these attributes in its function directory: + + =============== ================================================== + ifname network device interface name associated with this + function instance + qmult queue length multiplier for high and super speed + host_addr MAC address of host's end of this + Ethernet over USB link + dev_addr MAC address of device's end of this + Ethernet over USB link + =============== ================================================== + +and after creating the functions/rndis.<instance name> they contain default +values: qmult is 5, dev_addr and host_addr are randomly selected. +The ifname can be written to if the function is not bound. A write must be an +interface pattern such as "usb%d", which will cause the net core to choose the +next free usbX interface. By default, it is set to "usb%d". + +Testing the RNDIS function +-------------------------- + +Configure IP addresses of the device and the host. Then: + +On the device:: + + ping <host's IP> + +On the host:: + + ping <device's IP> + +14. SERIAL function +=================== + +The function is provided by usb_f_gser.ko module. + +Function-specific configfs interface +------------------------------------ + +The function name to use when creating the function directory is "gser". +The SERIAL function provides just one attribute in its function directory: + + port_num + +The attribute is read-only. + +There can be at most 4 ACM/generic serial/OBEX ports in the system. + +Testing the SERIAL function +--------------------------- + +On host:: + + insmod usbserial + echo VID PID >/sys/bus/usb-serial/drivers/generic/new_id + +On host:: + + cat > /dev/ttyUSB<X> + +On target:: + + cat /dev/ttyGS<Y> + +then the other way round + +On target:: + + cat > /dev/ttyGS<Y> + +On host:: + + cat /dev/ttyUSB<X> + +15. SOURCESINK function +======================= + +The function is provided by usb_f_ss_lb.ko module. + +Function-specific configfs interface +------------------------------------ + +The function name to use when creating the function directory is "SourceSink". +The SOURCESINK function provides these attributes in its function directory: + + =============== ================================== + pattern 0 (all zeros), 1 (mod63), 2 (none) + isoc_interval 1..16 + isoc_maxpacket 0 - 1023 (fs), 0 - 1024 (hs/ss) + isoc_mult 0..2 (hs/ss only) + isoc_maxburst 0..15 (ss only) + bulk_buflen buffer length + bulk_qlen depth of queue for bulk + iso_qlen depth of queue for iso + =============== ================================== + +Testing the SOURCESINK function +------------------------------- + +device: run the gadget + +host: test-usb (tools/usb/testusb.c) + + +16. UAC1 function (legacy implementation) +========================================= + +The function is provided by usb_f_uac1_legacy.ko module. + +Function-specific configfs interface +------------------------------------ + +The function name to use when creating the function directory +is "uac1_legacy". +The uac1 function provides these attributes in its function directory: + + =============== ==================================== + audio_buf_size audio buffer size + fn_cap capture pcm device file name + fn_cntl control device file name + fn_play playback pcm device file name + req_buf_size ISO OUT endpoint request buffer size + req_count ISO OUT endpoint request count + =============== ==================================== + +The attributes have sane default values. + +Testing the UAC1 function +------------------------- + +device: run the gadget + +host:: + + aplay -l # should list our USB Audio Gadget + +17. UAC2 function +================= + +The function is provided by usb_f_uac2.ko module. + +Function-specific configfs interface +------------------------------------ + +The function name to use when creating the function directory is "uac2". +The uac2 function provides these attributes in its function directory: + + ================ ==================================================== + c_chmask capture channel mask + c_srate list of capture sampling rates (comma-separated) + c_ssize capture sample size (bytes) + c_sync capture synchronization type (async/adaptive) + c_mute_present capture mute control enable + c_volume_present capture volume control enable + c_volume_min capture volume control min value (in 1/256 dB) + c_volume_max capture volume control max value (in 1/256 dB) + c_volume_res capture volume control resolution (in 1/256 dB) + c_hs_bint capture bInterval for HS/SS (1-4: fixed, 0: auto) + fb_max maximum extra bandwidth in async mode + p_chmask playback channel mask + p_srate list of playback sampling rates (comma-separated) + p_ssize playback sample size (bytes) + p_mute_present playback mute control enable + p_volume_present playback volume control enable + p_volume_min playback volume control min value (in 1/256 dB) + p_volume_max playback volume control max value (in 1/256 dB) + p_volume_res playback volume control resolution (in 1/256 dB) + p_hs_bint playback bInterval for HS/SS (1-4: fixed, 0: auto) + req_number the number of pre-allocated request for both capture + and playback + function_name name of the interface + ================ ==================================================== + +The attributes have sane default values. + +Testing the UAC2 function +------------------------- + +device: run the gadget +host: aplay -l # should list our USB Audio Gadget + +This function does not require real hardware support, it just +sends a stream of audio data to/from the host. In order to +actually hear something at the device side, a command similar +to this must be used at the device side:: + + $ arecord -f dat -t wav -D hw:2,0 | aplay -D hw:0,0 & + +e.g.:: + + $ arecord -f dat -t wav -D hw:CARD=UAC2Gadget,DEV=0 | \ + aplay -D default:CARD=OdroidU3 + +18. UVC function +================ + +The function is provided by usb_f_uvc.ko module. + +Function-specific configfs interface +------------------------------------ + +The function name to use when creating the function directory is "uvc". +The uvc function provides these attributes in its function directory: + + =================== ================================================ + streaming_interval interval for polling endpoint for data transfers + streaming_maxburst bMaxBurst for super speed companion descriptor + streaming_maxpacket maximum packet size this endpoint is capable of + sending or receiving when this configuration is + selected + function_name name of the interface + =================== ================================================ + +There are also "control" and "streaming" subdirectories, each of which contain +a number of their subdirectories. There are some sane defaults provided, but +the user must provide the following: + + ================== ==================================================== + control header create in control/header, link from control/class/fs + and/or control/class/ss + streaming header create in streaming/header, link from + streaming/class/fs and/or streaming/class/hs and/or + streaming/class/ss + format description create in streaming/mjpeg and/or + streaming/uncompressed + frame description create in streaming/mjpeg/<format> and/or in + streaming/uncompressed/<format> + ================== ==================================================== + +Each frame description contains frame interval specification, and each +such specification consists of a number of lines with an interval value +in each line. The rules stated above are best illustrated with an example:: + + # mkdir functions/uvc.usb0/control/header/h + # cd functions/uvc.usb0/control/ + # ln -s header/h class/fs + # ln -s header/h class/ss + # mkdir -p functions/uvc.usb0/streaming/uncompressed/u/360p + # cat <<EOF > functions/uvc.usb0/streaming/uncompressed/u/360p/dwFrameInterval + 666666 + 1000000 + 5000000 + EOF + # cd $GADGET_CONFIGFS_ROOT + # mkdir functions/uvc.usb0/streaming/header/h + # cd functions/uvc.usb0/streaming/header/h + # ln -s ../../uncompressed/u + # cd ../../class/fs + # ln -s ../../header/h + # cd ../../class/hs + # ln -s ../../header/h + # cd ../../class/ss + # ln -s ../../header/h + + +Testing the UVC function +------------------------ + +device: run the gadget, modprobe vivid:: + + # uvc-gadget -u /dev/video<uvc video node #> -v /dev/video<vivid video node #> + +where uvc-gadget is this program: + http://git.ideasonboard.org/uvc-gadget.git + +with these patches: + + http://www.spinics.net/lists/linux-usb/msg99220.html + +host:: + + luvcview -f yuv + +19. PRINTER function +==================== + +The function is provided by usb_f_printer.ko module. + +Function-specific configfs interface +------------------------------------ + +The function name to use when creating the function directory is "printer". +The printer function provides these attributes in its function directory: + + ========== =========================================== + pnp_string Data to be passed to the host in pnp string + q_len Number of requests per endpoint + ========== =========================================== + +Testing the PRINTER function +---------------------------- + +The most basic testing: + +device: run the gadget:: + + # ls -l /devices/virtual/usb_printer_gadget/ + +should show g_printer<number>. + +If udev is active, then /dev/g_printer<number> should appear automatically. + +host: + +If udev is active, then e.g. /dev/usb/lp0 should appear. + +host->device transmission: + +device:: + + # cat /dev/g_printer<number> + +host:: + + # cat > /dev/usb/lp0 + +device->host transmission:: + + # cat > /dev/g_printer<number> + +host:: + + # cat /dev/usb/lp0 + +More advanced testing can be done with the prn_example +described in Documentation/usb/gadget_printer.rst. + + +20. UAC1 function (virtual ALSA card, using u_audio API) +======================================================== + +The function is provided by usb_f_uac1.ko module. +It will create a virtual ALSA card and the audio streams are simply +sinked to and sourced from it. + +Function-specific configfs interface +------------------------------------ + +The function name to use when creating the function directory is "uac1". +The uac1 function provides these attributes in its function directory: + + ================ ==================================================== + c_chmask capture channel mask + c_srate list of capture sampling rates (comma-separated) + c_ssize capture sample size (bytes) + c_mute_present capture mute control enable + c_volume_present capture volume control enable + c_volume_min capture volume control min value (in 1/256 dB) + c_volume_max capture volume control max value (in 1/256 dB) + c_volume_res capture volume control resolution (in 1/256 dB) + p_chmask playback channel mask + p_srate list of playback sampling rates (comma-separated) + p_ssize playback sample size (bytes) + p_mute_present playback mute control enable + p_volume_present playback volume control enable + p_volume_min playback volume control min value (in 1/256 dB) + p_volume_max playback volume control max value (in 1/256 dB) + p_volume_res playback volume control resolution (in 1/256 dB) + req_number the number of pre-allocated requests for both capture + and playback + function_name name of the interface + ================ ==================================================== + +The attributes have sane default values. + +Testing the UAC1 function +------------------------- + +device: run the gadget +host: aplay -l # should list our USB Audio Gadget + +This function does not require real hardware support, it just +sends a stream of audio data to/from the host. In order to +actually hear something at the device side, a command similar +to this must be used at the device side:: + + $ arecord -f dat -t wav -D hw:2,0 | aplay -D hw:0,0 & + +e.g.:: + + $ arecord -f dat -t wav -D hw:CARD=UAC1Gadget,DEV=0 | \ + aplay -D default:CARD=OdroidU3 + + +21. MIDI2 function +================== + +The function is provided by usb_f_midi2.ko module. +It will create a virtual ALSA card containing a UMP rawmidi device +where the UMP packet is looped back. In addition, a legacy rawmidi +device is created. The UMP rawmidi is bound with ALSA sequencer +clients, too. + +Function-specific configfs interface +------------------------------------ + +The function name to use when creating the function directory is "midi2". +The midi2 function provides these attributes in its function directory +as the card top-level information: + + ============= ================================================= + process_ump Bool flag to process UMP Stream messages (0 or 1) + static_block Bool flag for static blocks (0 or 1) + iface_name Optional interface name string + ============= ================================================= + +The directory contains a subdirectory "ep.0", and this provides the +attributes for a UMP Endpoint (which is a pair of USB MIDI Endpoints): + + ============= ================================================= + protocol_caps MIDI protocol capabilities; + 1: MIDI 1.0, 2: MIDI 2.0, or 3: both protocols + protocol Default MIDI protocol (either 1 or 2) + ep_name UMP Endpoint name string + product_id Product ID string + manufacturer Manufacture ID number (24 bit) + family Device family ID number (16 bit) + model Device model ID number (16 bit) + sw_revision Software revision (32 bit) + ============= ================================================= + +Each Endpoint subdirectory contains a subdirectory "block.0", which +represents the Function Block for Block 0 information. +Its attributes are: + + ================= =============================================== + name Function Block name string + direction Direction of this FB + 1: input, 2: output, or 3: bidirectional + first_group The first UMP Group number (0-15) + num_groups The number of groups in this FB (1-16) + midi1_first_group The first UMP Group number for MIDI 1.0 (0-15) + midi1_num_groups The number of groups for MIDI 1.0 (0-16) + ui_hint UI-hint of this FB + 0: unknown, 1: receiver, 2: sender, 3: both + midi_ci_verison Supported MIDI-CI version number (8 bit) + is_midi1 Legacy MIDI 1.0 device (0-2) + 0: MIDI 2.0 device, + 1: MIDI 1.0 without restriction, or + 2: MIDI 1.0 with low speed + sysex8_streams Max number of SysEx8 streams (8 bit) + active Bool flag for FB activity (0 or 1) + ================= =============================================== + +If multiple Function Blocks are required, you can add more Function +Blocks by creating subdirectories "block.<num>" with the corresponding +Function Block number (1, 2, ....). The FB subdirectories can be +dynamically removed, too. Note that the Function Block numbers must be +continuous. + +Similarly, if you multiple UMP Endpoints are required, you can add +more Endpoints by creating subdirectories "ep.<num>". The number must +be continuous. + +For emulating the old MIDI 2.0 device without UMP v1.1 support, pass 0 +to `process_ump` flag. Then the whole UMP v1.1 requests are ignored. + +Testing the MIDI2 function +-------------------------- + +On the device: run the gadget, and running:: + + $ cat /proc/asound/cards + +will show a new sound card containing a MIDI2 device. + +OTOH, on the host:: + + $ cat /proc/asound/cards + +will show a new sound card containing either MIDI1 or MIDI2 device, +depending on the USB audio driver configuration. + +On both, when ALSA sequencer is enabled on the host, you can find the +UMP MIDI client such as "MIDI 2.0 Gadget". + +As the driver simply loops back the data, there is no need for a real +device just for testing. + +For testing a MIDI input from the gadget to the host (e.g. emulating a +MIDI keyboard), you can send a MIDI stream like the following. + +On the gadget:: + + $ aconnect -o + .... + client 20: 'MIDI 2.0 Gadget' [type=kernel,card=1] + 0 'MIDI 2.0 ' + 1 'Group 1 (MIDI 2.0 Gadget I/O)' + $ aplaymidi -p 20:1 to_host.mid + +On the host:: + + $ aconnect -i + .... + client 24: 'MIDI 2.0 Gadget' [type=kernel,card=2] + 0 'MIDI 2.0 ' + 1 'Group 1 (MIDI 2.0 Gadget I/O)' + $ arecordmidi -p 24:1 from_gadget.mid + +If you have a UMP-capable application, you can use the UMP port to +send/receive the raw UMP packets, too. For example, aseqdump program +with UMP support can receive from UMP port. On the host:: + + $ aseqdump -u 2 -p 24:1 + Waiting for data. Press Ctrl+C to end. + Source Group Event Ch Data + 24:1 Group 0, Program change 0, program 0, Bank select 0:0 + 24:1 Group 0, Channel pressure 0, value 0x80000000 + +For testing a MIDI output to the gadget to the host (e.g. emulating a +MIDI synth), it'll be just other way round. + +On the gadget:: + + $ arecordmidi -p 20:1 from_host.mid + +On the host:: + + $ aplaymidi -p 24:1 to_gadget.mid + +The access to MIDI 1.0 on altset 0 on the host is supported, and it's +translated from/to UMP packets on the gadget. It's bound to only +Function Block 0. + +The current operation mode can be observed in ALSA control element +"Operation Mode" for SND_CTL_IFACE_RAWMIDI. For example:: + + $ amixer -c1 contents + numid=1,iface=RAWMIDI,name='Operation Mode' + ; type=INTEGER,access=r--v----,values=1,min=0,max=2,step=0 + : values=2 + +where 0 = unused, 1 = MIDI 1.0 (altset 0), 2 = MIDI 2.0 (altset 1). +The example above shows it's running in 2, i.e. MIDI 2.0. |