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e38eb2c8 AP |
1 | This file summarizes information on basic testing of USB functions |
2 | provided by gadgets. | |
3 | ||
4 | 1. ACM function | |
d5862ca6 | 5 | 2. ECM function |
7bfbc6e3 | 6 | 3. ECM subset function |
4ca560a6 | 7 | 4. EEM function |
2c0f62f9 | 8 | 5. FFS function |
f7e3c3cd | 9 | 6. HID function |
ec91aff7 | 10 | 7. LOOPBACK function |
cdbe287d | 11 | 8. MASS STORAGE function |
0d6be59a | 12 | 9. MIDI function |
e38eb2c8 AP |
13 | |
14 | ||
15 | 1. ACM function | |
16 | =============== | |
17 | ||
18 | The function is provided by usb_f_acm.ko module. | |
19 | ||
20 | Function-specific configfs interface | |
21 | ------------------------------------ | |
22 | ||
23 | The function name to use when creating the function directory is "acm". | |
24 | The ACM function provides just one attribute in its function directory: | |
25 | ||
26 | port_num | |
27 | ||
28 | The attribute is read-only. | |
29 | ||
30 | There can be at most 4 ACM/generic serial/OBEX ports in the system. | |
31 | ||
32 | ||
33 | Testing the ACM function | |
34 | ------------------------ | |
35 | ||
36 | On the host: cat > /dev/ttyACM<X> | |
37 | On the device : cat /dev/ttyGS<Y> | |
38 | ||
39 | then the other way round | |
40 | ||
41 | On the device: cat > /dev/ttyGS<Y> | |
42 | On the host: cat /dev/ttyACM<X> | |
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43 | |
44 | 2. ECM function | |
45 | =============== | |
46 | ||
47 | The function is provided by usb_f_ecm.ko module. | |
48 | ||
49 | Function-specific configfs interface | |
50 | ------------------------------------ | |
51 | ||
52 | The function name to use when creating the function directory is "ecm". | |
53 | The ECM function provides these attributes in its function directory: | |
54 | ||
55 | ifname - network device interface name associated with this | |
56 | function instance | |
57 | qmult - queue length multiplier for high and super speed | |
58 | host_addr - MAC address of host's end of this | |
59 | Ethernet over USB link | |
60 | dev_addr - MAC address of device's end of this | |
61 | Ethernet over USB link | |
62 | ||
63 | and after creating the functions/ecm.<instance name> they contain default | |
64 | values: qmult is 5, dev_addr and host_addr are randomly selected. | |
65 | Except for ifname they can be written to until the function is linked to a | |
66 | configuration. The ifname is read-only and contains the name of the interface | |
67 | which was assigned by the net core, e. g. usb0. | |
68 | ||
69 | Testing the ECM function | |
70 | ------------------------ | |
71 | ||
72 | Configure IP addresses of the device and the host. Then: | |
73 | ||
74 | On the device: ping <host's IP> | |
75 | On the host: ping <device's IP> | |
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76 | |
77 | 3. ECM subset function | |
78 | ====================== | |
79 | ||
80 | The function is provided by usb_f_ecm_subset.ko module. | |
81 | ||
82 | Function-specific configfs interface | |
83 | ------------------------------------ | |
84 | ||
85 | The function name to use when creating the function directory is "geth". | |
86 | The ECM subset function provides these attributes in its function directory: | |
87 | ||
88 | ifname - network device interface name associated with this | |
89 | function instance | |
90 | qmult - queue length multiplier for high and super speed | |
91 | host_addr - MAC address of host's end of this | |
92 | Ethernet over USB link | |
93 | dev_addr - MAC address of device's end of this | |
94 | Ethernet over USB link | |
95 | ||
96 | and after creating the functions/ecm.<instance name> they contain default | |
97 | values: qmult is 5, dev_addr and host_addr are randomly selected. | |
98 | Except for ifname they can be written to until the function is linked to a | |
99 | configuration. The ifname is read-only and contains the name of the interface | |
100 | which was assigned by the net core, e. g. usb0. | |
101 | ||
102 | Testing the ECM subset function | |
103 | ------------------------------- | |
104 | ||
105 | Configure IP addresses of the device and the host. Then: | |
106 | ||
107 | On the device: ping <host's IP> | |
108 | On the host: ping <device's IP> | |
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109 | |
110 | 4. EEM function | |
111 | =============== | |
112 | ||
113 | The function is provided by usb_f_eem.ko module. | |
114 | ||
115 | Function-specific configfs interface | |
116 | ------------------------------------ | |
117 | ||
118 | The function name to use when creating the function directory is "eem". | |
119 | The EEM function provides these attributes in its function directory: | |
120 | ||
121 | ifname - network device interface name associated with this | |
122 | function instance | |
123 | qmult - queue length multiplier for high and super speed | |
124 | host_addr - MAC address of host's end of this | |
125 | Ethernet over USB link | |
126 | dev_addr - MAC address of device's end of this | |
127 | Ethernet over USB link | |
128 | ||
129 | and after creating the functions/eem.<instance name> they contain default | |
130 | values: qmult is 5, dev_addr and host_addr are randomly selected. | |
131 | Except for ifname they can be written to until the function is linked to a | |
132 | configuration. The ifname is read-only and contains the name of the interface | |
133 | which was assigned by the net core, e. g. usb0. | |
134 | ||
135 | Testing the EEM function | |
136 | ------------------------ | |
137 | ||
138 | Configure IP addresses of the device and the host. Then: | |
139 | ||
140 | On the device: ping <host's IP> | |
141 | On the host: ping <device's IP> | |
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142 | |
143 | 5. FFS function | |
144 | =============== | |
145 | ||
146 | The function is provided by usb_f_fs.ko module. | |
147 | ||
148 | Function-specific configfs interface | |
149 | ------------------------------------ | |
150 | ||
151 | The function name to use when creating the function directory is "ffs". | |
152 | The function directory is intentionally empty and not modifiable. | |
153 | ||
154 | After creating the directory there is a new instance (a "device") of FunctionFS | |
155 | available in the system. Once a "device" is available, the user should follow | |
156 | the standard procedure for using FunctionFS (mount it, run the userspace | |
157 | process which implements the function proper). The gadget should be enabled | |
158 | by writing a suitable string to usb_gadget/<gadget>/UDC. | |
159 | ||
160 | Testing the FFS function | |
161 | ------------------------ | |
162 | ||
163 | On the device: start the function's userspace daemon, enable the gadget | |
164 | On the host: use the USB function provided by the device | |
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165 | |
166 | 6. HID function | |
167 | =============== | |
168 | ||
169 | The function is provided by usb_f_hid.ko module. | |
170 | ||
171 | Function-specific configfs interface | |
172 | ------------------------------------ | |
173 | ||
174 | The function name to use when creating the function directory is "hid". | |
175 | The HID function provides these attributes in its function directory: | |
176 | ||
177 | protocol - HID protocol to use | |
178 | report_desc - data to be used in HID reports, except data | |
179 | passed with /dev/hidg<X> | |
180 | report_length - HID report length | |
181 | subclass - HID subclass to use | |
182 | ||
183 | For a keyboard the protocol and the subclass are 1, the report_length is 8, | |
184 | while the report_desc is: | |
185 | ||
186 | $ hd my_report_desc | |
187 | 00000000 05 01 09 06 a1 01 05 07 19 e0 29 e7 15 00 25 01 |..........)...%.| | |
188 | 00000010 75 01 95 08 81 02 95 01 75 08 81 03 95 05 75 01 |u.......u.....u.| | |
189 | 00000020 05 08 19 01 29 05 91 02 95 01 75 03 91 03 95 06 |....).....u.....| | |
190 | 00000030 75 08 15 00 25 65 05 07 19 00 29 65 81 00 c0 |u...%e....)e...| | |
191 | 0000003f | |
192 | ||
193 | Such a sequence of bytes can be stored to the attribute with echo: | |
194 | ||
195 | $ echo -ne \\x05\\x01\\x09\\x06\\xa1..... | |
196 | ||
197 | Testing the HID function | |
198 | ------------------------ | |
199 | ||
200 | Device: | |
201 | - create the gadget | |
202 | - connect the gadget to a host, preferably not the one used | |
203 | to control the gadget | |
204 | - run a program which writes to /dev/hidg<N>, e.g. | |
205 | a userspace program found in Documentation/usb/gadget_hid.txt: | |
206 | ||
207 | $ ./hid_gadget_test /dev/hidg0 keyboard | |
208 | ||
209 | Host: | |
210 | - observe the keystrokes from the gadget | |
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211 | |
212 | 7. LOOPBACK function | |
213 | ==================== | |
214 | ||
215 | The function is provided by usb_f_ss_lb.ko module. | |
216 | ||
217 | Function-specific configfs interface | |
218 | ------------------------------------ | |
219 | ||
220 | The function name to use when creating the function directory is "Loopback". | |
221 | The LOOPBACK function provides these attributes in its function directory: | |
222 | ||
223 | qlen - depth of loopback queue | |
224 | bulk_buflen - buffer length | |
225 | ||
226 | Testing the LOOPBACK function | |
227 | ----------------------------- | |
228 | ||
229 | device: run the gadget | |
230 | host: test-usb | |
231 | ||
232 | http://www.linux-usb.org/usbtest/testusb.c | |
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233 | |
234 | 8. MASS STORAGE function | |
235 | ======================== | |
236 | ||
237 | The function is provided by usb_f_mass_storage.ko module. | |
238 | ||
239 | Function-specific configfs interface | |
240 | ------------------------------------ | |
241 | ||
242 | The function name to use when creating the function directory is "mass_storage". | |
243 | The MASS STORAGE function provides these attributes in its directory: | |
244 | files: | |
245 | ||
246 | stall - Set to permit function to halt bulk endpoints. | |
247 | Disabled on some USB devices known not to work | |
248 | correctly. You should set it to true. | |
249 | num_buffers - Number of pipeline buffers. Valid numbers | |
250 | are 2..4. Available only if | |
251 | CONFIG_USB_GADGET_DEBUG_FILES is set. | |
252 | ||
253 | and a default lun.0 directory corresponding to SCSI LUN #0. | |
254 | ||
255 | A new lun can be added with mkdir: | |
256 | ||
257 | $ mkdir functions/mass_storage.0/partition.5 | |
258 | ||
259 | Lun numbering does not have to be continuous, except for lun #0 which is | |
260 | created by default. A maximum of 8 luns can be specified and they all must be | |
261 | named following the <name>.<number> scheme. The numbers can be 0..8. | |
262 | Probably a good convention is to name the luns "lun.<number>", | |
263 | although it is not mandatory. | |
264 | ||
265 | In each lun directory there are the following attribute files: | |
266 | ||
267 | file - The path to the backing file for the LUN. | |
268 | Required if LUN is not marked as removable. | |
269 | ro - Flag specifying access to the LUN shall be | |
270 | read-only. This is implied if CD-ROM emulation | |
271 | is enabled as well as when it was impossible | |
272 | to open "filename" in R/W mode. | |
273 | removable - Flag specifying that LUN shall be indicated as | |
274 | being removable. | |
275 | cdrom - Flag specifying that LUN shall be reported as | |
276 | being a CD-ROM. | |
277 | nofua - Flag specifying that FUA flag | |
278 | in SCSI WRITE(10,12) | |
279 | ||
280 | Testing the MASS STORAGE function | |
281 | --------------------------------- | |
282 | ||
283 | device: connect the gadget, enable it | |
284 | host: dmesg, see the USB drives appear (if system configured to automatically | |
285 | mount) | |
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286 | |
287 | 9. MIDI function | |
288 | ================ | |
289 | ||
290 | The function is provided by usb_f_midi.ko module. | |
291 | ||
292 | Function-specific configfs interface | |
293 | ------------------------------------ | |
294 | ||
295 | The function name to use when creating the function directory is "midi". | |
296 | The MIDI function provides these attributes in its function directory: | |
297 | ||
298 | buflen - MIDI buffer length | |
299 | id - ID string for the USB MIDI adapter | |
300 | in_ports - number of MIDI input ports | |
301 | index - index value for the USB MIDI adapter | |
302 | out_ports - number of MIDI output ports | |
303 | qlen - USB read request queue length | |
304 | ||
305 | Testing the MIDI function | |
306 | ------------------------- | |
307 | ||
308 | There are two cases: playing a mid from the gadget to | |
309 | the host and playing a mid from the host to the gadget. | |
310 | ||
311 | 1) Playing a mid from the gadget to the host | |
312 | host) | |
313 | ||
314 | $ arecordmidi -l | |
315 | Port Client name Port name | |
316 | 14:0 Midi Through Midi Through Port-0 | |
317 | 24:0 MIDI Gadget MIDI Gadget MIDI 1 | |
318 | $ arecordmidi -p 24:0 from_gadget.mid | |
319 | ||
320 | gadget) | |
321 | ||
322 | $ aplaymidi -l | |
323 | Port Client name Port name | |
324 | 20:0 f_midi f_midi | |
325 | ||
326 | $ aplaymidi -p 20:0 to_host.mid | |
327 | ||
328 | 2) Playing a mid from the host to the gadget | |
329 | gadget) | |
330 | ||
331 | $ arecordmidi -l | |
332 | Port Client name Port name | |
333 | 20:0 f_midi f_midi | |
334 | ||
335 | $ arecordmidi -p 20:0 from_host.mid | |
336 | ||
337 | host) | |
338 | ||
339 | $ aplaymidi -l | |
340 | Port Client name Port name | |
341 | 14:0 Midi Through Midi Through Port-0 | |
342 | 24:0 MIDI Gadget MIDI Gadget MIDI 1 | |
343 | ||
344 | $ aplaymidi -p24:0 to_gadget.mid | |
345 | ||
346 | The from_gadget.mid should sound identical to the to_host.mid. | |
347 | The from_host.id should sound identical to the to_gadget.mid. | |
348 | ||
349 | MIDI files can be played to speakers/headphones with e.g. timidity installed | |
350 | ||
351 | $ aplaymidi -l | |
352 | Port Client name Port name | |
353 | 14:0 Midi Through Midi Through Port-0 | |
354 | 24:0 MIDI Gadget MIDI Gadget MIDI 1 | |
355 | 128:0 TiMidity TiMidity port 0 | |
356 | 128:1 TiMidity TiMidity port 1 | |
357 | 128:2 TiMidity TiMidity port 2 | |
358 | 128:3 TiMidity TiMidity port 3 | |
359 | ||
360 | $ aplaymidi -p 128:0 file.mid | |
361 | ||
362 | MIDI ports can be logically connected using the aconnect utility, e.g.: | |
363 | ||
364 | $ aconnect 24:0 128:0 # try it on the host | |
365 | ||
366 | After the gadget's MIDI port is connected to timidity's MIDI port, | |
367 | whatever is played at the gadget side with aplaymidi -l is audible | |
368 | in host's speakers/headphones. |