While trying to debug some issues on a driver on Linux, and using a Beagleboard card as a hardware USB sniffer[1], I noticed the need of having a parser to work with the sniffer data. While wireshark provides a good way of looking into the info, most of the times, I just want to convert the data into something more concise that allows me to work on a char terminal, and that allows to use a device-specific parser that translates an obscure log into device-specific register reads and writes. [1] using the code available at: http://beagleboard-usbsniffer.blogspot.com/ So, I wrote a parser, in perl, called parse_tcpdump_log.pl. The current version is, in fact, more than a parser, as it allows both parsing a previously captured log, or to start a capture and parse data in real time. The script is available at the v4l-utils tree, on: http://git.linuxtv.org/v4l-utils.git?a=blob;f=contrib/parse_tcpdump_log.pl;h=f90e981125462a58cadefa607cbff0ecb4b5ed45;hb=HEAD At the output, each line is a URB data control transfer. The script groups the request and the complete URB's into one line, so, each line of the dump will correspond to a call to usb_control_msg(). The output is: 000000000 ms 000000 ms (000127 us EP=80) 80 06 00 01 00 00 28 00 >>> 12 01 00 02 00 00 00 40 40 20 13 65 10 01 00 01 02 01 000000000 ms 000000 ms (000002 us EP=80) 80 06 00 01 00 00 28 00 >>> 12 01 00 02 09 00 00 40 6b 1d 02 00 06 02 03 02 01 01 000000006 ms 000005 ms (000239 us EP=80) c0 00 00 00 45 00 03 00 <<< 00 00 10 000001006 ms 001000 ms (000112 us EP=80) c0 00 00 00 45 00 03 00 <<< 00 00 10 000001106 ms 000100 ms (000150 us EP=80) c0 00 00 00 45 00 03 00 <<< 00 00 10 The provided info on each of the above lines are: - Time from the script start; - Time from the last transaction; - Time between URB send request and URB response; - Endpoint for the transfer; - 8 bytes with the following URB fields: - Type (1 byte); - Request (1 byte); - wValue (2 bytes); - wIndex (2 bytes); - wLength (2 bytes); - URB direction: >>> - To URB device <<< - To host - Optional data (length is given by wLength). It is also possible to produce a detailed log, when used with "--debug 2", like: PARSED data: RAW: ID => 0xffff880105a53f00 RAW: Payload => 00000000000000000000000000000000000200000000000012010002090000406b1d0200060203020101 RAW: Time => 1300309970.745112 RAW: Status => 0 RAW: ArrivalTime => 5584788795812741120.745112 RAW: URBLength => 18 RAW: TransferType => 2 RAW: Device => 1 RAW: Type => C RAW: DataLength => 18 RAW: BusID => 1 RAW: HasData => present RAW: Endpoint => 128 RAW: PayloadSize => 42 RAW: SetupRequest => not present There are a few other parsers at the v4l-utils git tree that can work with the default output format and produce a device-specific output. For example, the parser_em28xx.pl will produce a code that will look close to the C clauses inside the em28xx driver. So, for a real-time debug of the em28xx driver, for example, it will do: # ./parse_tcpdump_log.pl --pcap |./parse_em28xx.pl em28xx_read_reg(dev, EM28XX_R26_COMPR); /* read 0x0c */ em28xx_write_reg(dev, EM28XX_R26_COMPR, 0x0c); i2c_master_send(0xb8>>1, { 02 00 }, 0x02); i2c_master_send(0xb8>>1, { 00 00 }, 0x02); i2c_master_send(0xb8>>1, { 03 }, 0x01); i2c_master_recv(0xb8>>1, &buf, 0x01); /* 6f */ em28xx_read_reg(dev, 0x05); /* read 0x00 */ i2c_master_send(0xb8>>1, { 03 6f }, 0x02); em28xx_write_ac97(dev, AC97_MASTER_VOL, 0x8000); em28xx_write_ac97(dev, AC97_LINE_LEVEL_VOL, 0x8000); em28xx_write_ac97(dev, AC97_MASTER_MONO_VOL, 0x8000); em28xx_write_ac97(dev, AC97_LFE_MASTER_VOL, 0x8000); I wrote a short summary on how to use it at: http://linuxtv.org/wiki/index.php/Bus_snooping/sniffing#Snooping_Procedures: The script also accepts the "--man" and "--help" parameters to produce a manpage or a help. In summary, I hope that this script will ease USB device driver debug and development. Feedback, fixes, etc are welcome. Have fun, Mauro. -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
