Andrzej Pietrasiewicz | e38eb2c | 2014-12-16 14:56:25 +0100 | [diff] [blame] | 1 | This file summarizes information on basic testing of USB functions |
| 2 | provided by gadgets. |
| 3 | |
| 4 | 1. ACM function |
Andrzej Pietrasiewicz | d5862ca | 2014-12-16 14:56:26 +0100 | [diff] [blame] | 5 | 2. ECM function |
Andrzej Pietrasiewicz | 7bfbc6e | 2014-12-16 14:56:27 +0100 | [diff] [blame] | 6 | 3. ECM subset function |
Andrzej Pietrasiewicz | 4ca560a | 2014-12-16 14:56:28 +0100 | [diff] [blame] | 7 | 4. EEM function |
Andrzej Pietrasiewicz | 2c0f62f | 2014-12-16 14:56:29 +0100 | [diff] [blame] | 8 | 5. FFS function |
Andrzej Pietrasiewicz | f7e3c3c | 2014-12-16 14:56:30 +0100 | [diff] [blame] | 9 | 6. HID function |
Andrzej Pietrasiewicz | ec91aff | 2014-12-16 14:56:31 +0100 | [diff] [blame] | 10 | 7. LOOPBACK function |
Andrzej Pietrasiewicz | cdbe287 | 2014-12-16 14:56:32 +0100 | [diff] [blame^] | 11 | 8. MASS STORAGE function |
Andrzej Pietrasiewicz | e38eb2c | 2014-12-16 14:56:25 +0100 | [diff] [blame] | 12 | |
| 13 | |
| 14 | 1. ACM function |
| 15 | =============== |
| 16 | |
| 17 | The function is provided by usb_f_acm.ko module. |
| 18 | |
| 19 | Function-specific configfs interface |
| 20 | ------------------------------------ |
| 21 | |
| 22 | The function name to use when creating the function directory is "acm". |
| 23 | The ACM function provides just one attribute in its function directory: |
| 24 | |
| 25 | port_num |
| 26 | |
| 27 | The attribute is read-only. |
| 28 | |
| 29 | There can be at most 4 ACM/generic serial/OBEX ports in the system. |
| 30 | |
| 31 | |
| 32 | Testing the ACM function |
| 33 | ------------------------ |
| 34 | |
| 35 | On the host: cat > /dev/ttyACM<X> |
| 36 | On the device : cat /dev/ttyGS<Y> |
| 37 | |
| 38 | then the other way round |
| 39 | |
| 40 | On the device: cat > /dev/ttyGS<Y> |
| 41 | On the host: cat /dev/ttyACM<X> |
Andrzej Pietrasiewicz | d5862ca | 2014-12-16 14:56:26 +0100 | [diff] [blame] | 42 | |
| 43 | 2. ECM function |
| 44 | =============== |
| 45 | |
| 46 | The function is provided by usb_f_ecm.ko module. |
| 47 | |
| 48 | Function-specific configfs interface |
| 49 | ------------------------------------ |
| 50 | |
| 51 | The function name to use when creating the function directory is "ecm". |
| 52 | The ECM function provides these attributes in its function directory: |
| 53 | |
| 54 | ifname - network device interface name associated with this |
| 55 | function instance |
| 56 | qmult - queue length multiplier for high and super speed |
| 57 | host_addr - MAC address of host's end of this |
| 58 | Ethernet over USB link |
| 59 | dev_addr - MAC address of device's end of this |
| 60 | Ethernet over USB link |
| 61 | |
| 62 | and after creating the functions/ecm.<instance name> they contain default |
| 63 | values: qmult is 5, dev_addr and host_addr are randomly selected. |
| 64 | Except for ifname they can be written to until the function is linked to a |
| 65 | configuration. The ifname is read-only and contains the name of the interface |
| 66 | which was assigned by the net core, e. g. usb0. |
| 67 | |
| 68 | Testing the ECM function |
| 69 | ------------------------ |
| 70 | |
| 71 | Configure IP addresses of the device and the host. Then: |
| 72 | |
| 73 | On the device: ping <host's IP> |
| 74 | On the host: ping <device's IP> |
Andrzej Pietrasiewicz | 7bfbc6e | 2014-12-16 14:56:27 +0100 | [diff] [blame] | 75 | |
| 76 | 3. ECM subset function |
| 77 | ====================== |
| 78 | |
| 79 | The function is provided by usb_f_ecm_subset.ko module. |
| 80 | |
| 81 | Function-specific configfs interface |
| 82 | ------------------------------------ |
| 83 | |
| 84 | The function name to use when creating the function directory is "geth". |
| 85 | The ECM subset function provides these attributes in its function directory: |
| 86 | |
| 87 | ifname - network device interface name associated with this |
| 88 | function instance |
| 89 | qmult - queue length multiplier for high and super speed |
| 90 | host_addr - MAC address of host's end of this |
| 91 | Ethernet over USB link |
| 92 | dev_addr - MAC address of device's end of this |
| 93 | Ethernet over USB link |
| 94 | |
| 95 | and after creating the functions/ecm.<instance name> they contain default |
| 96 | values: qmult is 5, dev_addr and host_addr are randomly selected. |
| 97 | Except for ifname they can be written to until the function is linked to a |
| 98 | configuration. The ifname is read-only and contains the name of the interface |
| 99 | which was assigned by the net core, e. g. usb0. |
| 100 | |
| 101 | Testing the ECM subset function |
| 102 | ------------------------------- |
| 103 | |
| 104 | Configure IP addresses of the device and the host. Then: |
| 105 | |
| 106 | On the device: ping <host's IP> |
| 107 | On the host: ping <device's IP> |
Andrzej Pietrasiewicz | 4ca560a | 2014-12-16 14:56:28 +0100 | [diff] [blame] | 108 | |
| 109 | 4. EEM function |
| 110 | =============== |
| 111 | |
| 112 | The function is provided by usb_f_eem.ko module. |
| 113 | |
| 114 | Function-specific configfs interface |
| 115 | ------------------------------------ |
| 116 | |
| 117 | The function name to use when creating the function directory is "eem". |
| 118 | The EEM function provides these attributes in its function directory: |
| 119 | |
| 120 | ifname - network device interface name associated with this |
| 121 | function instance |
| 122 | qmult - queue length multiplier for high and super speed |
| 123 | host_addr - MAC address of host's end of this |
| 124 | Ethernet over USB link |
| 125 | dev_addr - MAC address of device's end of this |
| 126 | Ethernet over USB link |
| 127 | |
| 128 | and after creating the functions/eem.<instance name> they contain default |
| 129 | values: qmult is 5, dev_addr and host_addr are randomly selected. |
| 130 | Except for ifname they can be written to until the function is linked to a |
| 131 | configuration. The ifname is read-only and contains the name of the interface |
| 132 | which was assigned by the net core, e. g. usb0. |
| 133 | |
| 134 | Testing the EEM function |
| 135 | ------------------------ |
| 136 | |
| 137 | Configure IP addresses of the device and the host. Then: |
| 138 | |
| 139 | On the device: ping <host's IP> |
| 140 | On the host: ping <device's IP> |
Andrzej Pietrasiewicz | 2c0f62f | 2014-12-16 14:56:29 +0100 | [diff] [blame] | 141 | |
| 142 | 5. FFS function |
| 143 | =============== |
| 144 | |
| 145 | The function is provided by usb_f_fs.ko module. |
| 146 | |
| 147 | Function-specific configfs interface |
| 148 | ------------------------------------ |
| 149 | |
| 150 | The function name to use when creating the function directory is "ffs". |
| 151 | The function directory is intentionally empty and not modifiable. |
| 152 | |
| 153 | After creating the directory there is a new instance (a "device") of FunctionFS |
| 154 | available in the system. Once a "device" is available, the user should follow |
| 155 | the standard procedure for using FunctionFS (mount it, run the userspace |
| 156 | process which implements the function proper). The gadget should be enabled |
| 157 | by writing a suitable string to usb_gadget/<gadget>/UDC. |
| 158 | |
| 159 | Testing the FFS function |
| 160 | ------------------------ |
| 161 | |
| 162 | On the device: start the function's userspace daemon, enable the gadget |
| 163 | On the host: use the USB function provided by the device |
Andrzej Pietrasiewicz | f7e3c3c | 2014-12-16 14:56:30 +0100 | [diff] [blame] | 164 | |
| 165 | 6. HID function |
| 166 | =============== |
| 167 | |
| 168 | The function is provided by usb_f_hid.ko module. |
| 169 | |
| 170 | Function-specific configfs interface |
| 171 | ------------------------------------ |
| 172 | |
| 173 | The function name to use when creating the function directory is "hid". |
| 174 | The HID function provides these attributes in its function directory: |
| 175 | |
| 176 | protocol - HID protocol to use |
| 177 | report_desc - data to be used in HID reports, except data |
| 178 | passed with /dev/hidg<X> |
| 179 | report_length - HID report length |
| 180 | subclass - HID subclass to use |
| 181 | |
| 182 | For a keyboard the protocol and the subclass are 1, the report_length is 8, |
| 183 | while the report_desc is: |
| 184 | |
| 185 | $ hd my_report_desc |
| 186 | 00000000 05 01 09 06 a1 01 05 07 19 e0 29 e7 15 00 25 01 |..........)...%.| |
| 187 | 00000010 75 01 95 08 81 02 95 01 75 08 81 03 95 05 75 01 |u.......u.....u.| |
| 188 | 00000020 05 08 19 01 29 05 91 02 95 01 75 03 91 03 95 06 |....).....u.....| |
| 189 | 00000030 75 08 15 00 25 65 05 07 19 00 29 65 81 00 c0 |u...%e....)e...| |
| 190 | 0000003f |
| 191 | |
| 192 | Such a sequence of bytes can be stored to the attribute with echo: |
| 193 | |
| 194 | $ echo -ne \\x05\\x01\\x09\\x06\\xa1..... |
| 195 | |
| 196 | Testing the HID function |
| 197 | ------------------------ |
| 198 | |
| 199 | Device: |
| 200 | - create the gadget |
| 201 | - connect the gadget to a host, preferably not the one used |
| 202 | to control the gadget |
| 203 | - run a program which writes to /dev/hidg<N>, e.g. |
| 204 | a userspace program found in Documentation/usb/gadget_hid.txt: |
| 205 | |
| 206 | $ ./hid_gadget_test /dev/hidg0 keyboard |
| 207 | |
| 208 | Host: |
| 209 | - observe the keystrokes from the gadget |
Andrzej Pietrasiewicz | ec91aff | 2014-12-16 14:56:31 +0100 | [diff] [blame] | 210 | |
| 211 | 7. LOOPBACK function |
| 212 | ==================== |
| 213 | |
| 214 | The function is provided by usb_f_ss_lb.ko module. |
| 215 | |
| 216 | Function-specific configfs interface |
| 217 | ------------------------------------ |
| 218 | |
| 219 | The function name to use when creating the function directory is "Loopback". |
| 220 | The LOOPBACK function provides these attributes in its function directory: |
| 221 | |
| 222 | qlen - depth of loopback queue |
| 223 | bulk_buflen - buffer length |
| 224 | |
| 225 | Testing the LOOPBACK function |
| 226 | ----------------------------- |
| 227 | |
| 228 | device: run the gadget |
| 229 | host: test-usb |
| 230 | |
| 231 | http://www.linux-usb.org/usbtest/testusb.c |
Andrzej Pietrasiewicz | cdbe287 | 2014-12-16 14:56:32 +0100 | [diff] [blame^] | 232 | |
| 233 | 8. MASS STORAGE function |
| 234 | ======================== |
| 235 | |
| 236 | The function is provided by usb_f_mass_storage.ko module. |
| 237 | |
| 238 | Function-specific configfs interface |
| 239 | ------------------------------------ |
| 240 | |
| 241 | The function name to use when creating the function directory is "mass_storage". |
| 242 | The MASS STORAGE function provides these attributes in its directory: |
| 243 | files: |
| 244 | |
| 245 | stall - Set to permit function to halt bulk endpoints. |
| 246 | Disabled on some USB devices known not to work |
| 247 | correctly. You should set it to true. |
| 248 | num_buffers - Number of pipeline buffers. Valid numbers |
| 249 | are 2..4. Available only if |
| 250 | CONFIG_USB_GADGET_DEBUG_FILES is set. |
| 251 | |
| 252 | and a default lun.0 directory corresponding to SCSI LUN #0. |
| 253 | |
| 254 | A new lun can be added with mkdir: |
| 255 | |
| 256 | $ mkdir functions/mass_storage.0/partition.5 |
| 257 | |
| 258 | Lun numbering does not have to be continuous, except for lun #0 which is |
| 259 | created by default. A maximum of 8 luns can be specified and they all must be |
| 260 | named following the <name>.<number> scheme. The numbers can be 0..8. |
| 261 | Probably a good convention is to name the luns "lun.<number>", |
| 262 | although it is not mandatory. |
| 263 | |
| 264 | In each lun directory there are the following attribute files: |
| 265 | |
| 266 | file - The path to the backing file for the LUN. |
| 267 | Required if LUN is not marked as removable. |
| 268 | ro - Flag specifying access to the LUN shall be |
| 269 | read-only. This is implied if CD-ROM emulation |
| 270 | is enabled as well as when it was impossible |
| 271 | to open "filename" in R/W mode. |
| 272 | removable - Flag specifying that LUN shall be indicated as |
| 273 | being removable. |
| 274 | cdrom - Flag specifying that LUN shall be reported as |
| 275 | being a CD-ROM. |
| 276 | nofua - Flag specifying that FUA flag |
| 277 | in SCSI WRITE(10,12) |
| 278 | |
| 279 | Testing the MASS STORAGE function |
| 280 | --------------------------------- |
| 281 | |
| 282 | device: connect the gadget, enable it |
| 283 | host: dmesg, see the USB drives appear (if system configured to automatically |
| 284 | mount) |