+-- SysClk LWLA protocol dissector for Wireshark
+--
+-- Copyright (C) 2014 Daniel Elstner <daniel.kitta@gmail.com>
+--
+-- This program is free software; you can redistribute it and/or modify
+-- it under the terms of the GNU General Public License as published by
+-- the Free Software Foundation; either version 3 of the License, or
+-- (at your option) any later version.
+--
+-- This program is distributed in the hope that it will be useful,
+-- but WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+-- GNU General Public License for more details.
+--
+-- You should have received a copy of the GNU General Public License
+-- along with this program; if not, see <http://www.gnu.org/licenses/>.
+
+-- Usage: wireshark -X lua_script:sysclk-lwla-dissector.lua
+--
+-- It is not advisable to install this dissector globally, since
+-- it will try to interpret the communication of any USB device
+-- using the vendor-specific interface class.
+
+-- Create custom protocol for the LWLA logic analyzer.
+p_lwla = Proto("lwla", "LWLA USB Protocol")
+
+-- LWLA message type. For simplicity, the numerical value is the same
+-- as the USB end point number the message is sent to or comes from.
+local message_types = {
+ [2] = "Control command",
+ [4] = "Firmware transfer",
+ [6] = "Control response"
+}
+
+-- Known IDs of LWLA control commands.
+local control_commands = {
+ [1] = "Read register",
+ [2] = "Write register",
+ [5] = "Write ???",
+ [6] = "Read memory",
+ [7] = "Capture setup",
+ [8] = "Capture status"
+}
+
+-- Create the fields exhibited by the protocol.
+p_lwla.fields.msgtype = ProtoField.uint8("lwla.msgtype", "Message Type", base.DEC, message_types)
+p_lwla.fields.command = ProtoField.uint16("lwla.cmd", "Command ID", base.DEC, control_commands)
+p_lwla.fields.memaddr = ProtoField.uint32("lwla.memaddr", "Memory Address", base.HEX_DEC)
+p_lwla.fields.memlen = ProtoField.uint32("lwla.memlen", "Memory Read Length", base.HEX_DEC)
+p_lwla.fields.regaddr = ProtoField.uint16("lwla.regaddr", "Register Address", base.HEX)
+p_lwla.fields.regdata = ProtoField.uint32("lwla.regdata", "Register Value", base.HEX_DEC)
+p_lwla.fields.stataddr = ProtoField.uint16("lwla.stataddr", "Status Memory Address", base.HEX)
+p_lwla.fields.statlen = ProtoField.uint16("lwla.statlen", "Status Memory Read/Write Length", base.HEX_DEC)
+p_lwla.fields.statdata = ProtoField.bytes("lwla.statdata", "Status Word")
+p_lwla.fields.stopdata = ProtoField.uint32("lwla.stopdata", "Stop Data", base.HEX_DEC)
+p_lwla.fields.unknown = ProtoField.bytes("lwla.unknown", "Unidentified message data")
+
+-- Referenced USB URB dissector fields.
+local f_urb_type = Field.new("usb.urb_type")
+local f_transfer_type = Field.new("usb.transfer_type")
+local f_endpoint = Field.new("usb.endpoint_number.endpoint")
+
+-- Insert warning for undecoded leftover data.
+local function warn_undecoded(tree, range)
+ local item = tree:add(p_lwla.fields.unknown, range)
+ item:add_expert_info(PI_UNDECODED, PI_WARN, "Leftover data")
+end
+
+local function read_mixed_endian(range)
+ return range(0,2):le_uint() * 65536 + range(2,2):le_uint()
+end
+
+local function read_stat_field(range)
+ return string.char(range(5,1):uint(), range(4,1):uint(), range(7,1):uint(), range(6,1):uint(),
+ range(1,1):uint(), range(0,1):uint(), range(3,1):uint(), range(2,1):uint())
+end
+
+-- Dissect LWLA capture state.
+local function dissect_capture_state(range, tree)
+ for i = 0, range:len() - 8, 8 do
+ tree:add(p_lwla.fields.statdata, range(i,8), read_stat_field(range(i,8)))
+ end
+end
+
+-- Dissect LWLA control command messages.
+local function dissect_command(range, pinfo, tree)
+ if range:len() < 4 then
+ return 0
+ end
+
+ tree:add_le(p_lwla.fields.command, range(0,2))
+ local command = range(0,2):le_uint()
+
+ if command == 1 then -- read register
+ if range:len() == 4 then
+ tree:add_le(p_lwla.fields.regaddr, range(2,2))
+ pinfo.cols.info = string.format("Cmd %d: read reg 0x%04X",
+ command, range(2,2):le_uint())
+ return 4
+ end
+ elseif command == 2 then -- write register
+ if range:len() == 8 then
+ tree:add_le(p_lwla.fields.regaddr, range(2,2))
+ local regval = read_mixed_endian(range(4,4))
+ tree:add(p_lwla.fields.regdata, range(4,4), regval)
+ pinfo.cols.info = string.format("Cmd %d: write reg 0x%04X value 0x%08X",
+ command, range(2,2):le_uint(), regval)
+ return 8
+ end
+ elseif command == 5 then -- write ???
+ if range:len() == 66 then
+ local infotext = string.format("Cmd %d: write ??? data", command)
+ for i = 2, 62, 4 do
+ local value = read_mixed_endian(range(i,4))
+ tree:add(p_lwla.fields.stopdata, range(i,4), value)
+ infotext = string.format("%s %02X", infotext, value)
+ end
+ pinfo.cols.info = infotext
+ return 66
+ end
+ elseif command == 6 then -- read memory at address
+ if range:len() == 10 then
+ local memaddr = read_mixed_endian(range(2,4))
+ local memlen = read_mixed_endian(range(6,4))
+ tree:add(p_lwla.fields.memaddr, range(2,4), memaddr)
+ tree:add(p_lwla.fields.memlen, range(6,4), memlen)
+ pinfo.cols.info = string.format("Cmd %d: read mem 0x%06X length %d",
+ command, memaddr, memlen)
+ return 10
+ end
+ elseif command == 7 then -- capture setup
+ if range:len() >= 6 then
+ tree:add_le(p_lwla.fields.stataddr, range(2,2))
+ tree:add_le(p_lwla.fields.statlen, range(4,2))
+ local len = 8 * range(4,2):le_uint()
+ if range:len() ~= len + 6 then
+ warn_undecoded(tree, range(6))
+ return 6
+ end
+ dissect_capture_state(range(6,len), tree)
+ pinfo.cols.info = string.format("Cmd %d: setup 0x%X length %d",
+ command, range(2,2):le_uint(), range(4,2):le_uint())
+ return 6 + len
+ end
+ elseif command == 8 then -- capture status
+ if range:len() == 6 then
+ tree:add_le(p_lwla.fields.stataddr, range(2,2))
+ tree:add_le(p_lwla.fields.statlen, range(4,2))
+ pinfo.cols.info = string.format("Cmd %d: state 0x%X length %d",
+ command, range(2,2):le_uint(), range(4,2):le_uint())
+ return 6
+ end
+ end
+ warn_undecoded(tree, range(2))
+ return 2
+end
+
+-- Dissect LWLA control response messages.
+local function dissect_response(range, pinfo, tree)
+ -- The heuristics below are ugly and prone to fail, but they do the job
+ -- for the purposes this dissector was written.
+ if range:len() == 40 or range:len() == 80 then -- heuristic: response to command 8
+ dissect_capture_state(range, tree)
+ pinfo.cols.info = string.format("Ret 8: state length %d", range:len() / 8)
+ return range:len()
+ elseif range:len() == 4 then -- heuristic: response to command 1
+ local value = read_mixed_endian(range(0,4))
+ tree:add(p_lwla.fields.regdata, range(0,4), value)
+ pinfo.cols.info = string.format("Ret 1: reg value 0x%08X", value)
+ return 4
+ elseif range:len() >= 18 and range:len() % 18 == 0 then -- heuristic: response to command 6
+ pinfo.cols.info = string.format("Ret 6: mem data length %d", range:len() * 2 / 9)
+ return 0
+ else
+ return 0
+ end
+end
+
+-- Main LWLA dissector function.
+function p_lwla.dissector(tvb, pinfo, tree)
+ local transfer_type = tonumber(tostring(f_transfer_type()))
+
+ -- Bulk transfers only.
+ if transfer_type == 3 then
+ local urb_type = tonumber(tostring(f_urb_type()))
+ local endpoint = tonumber(tostring(f_endpoint()))
+
+ -- Payload-carrying packets only.
+ if (urb_type == 83 and (endpoint == 2 or endpoint == 4))
+ or (urb_type == 67 and endpoint == 6)
+ then
+ pinfo.cols.protocol = p_lwla.name
+
+ local subtree = tree:add(p_lwla, tvb(), "LWLA")
+ subtree:add(p_lwla.fields.msgtype, endpoint):set_generated()
+
+ -- Dispatch to message-specific dissection handler.
+ if endpoint == 2 then
+ return dissect_command(tvb, pinfo, subtree)
+ elseif endpoint == 4 then
+ pinfo.cols.info = "FPGA bitstream"
+ return 0
+ elseif endpoint == 6 then
+ return dissect_response(tvb, pinfo, subtree)
+ end
+ end
+ end
+ return 0
+end
+
+-- Register LWLA protocol dissector during initialization.
+function p_lwla.init()
+-- local usb_product_dissectors = DissectorTable.get("usb.product")
+
+ -- Dissection by vendor+product ID requires that Wireshark can get the
+ -- the device descriptor. Making a USB device available inside VirtualBox
+ -- will make it inaccessible from Linux, so Wireshark cannot fetch the
+ -- descriptor by itself. However, it is sufficient if the VirtualBox
+ -- guest requests the descriptor once while Wireshark is capturing.
+-- usb_product_dissectors:add(0x29616689, p_lwla)
+
+ -- Addendum: Protocol registration based on product ID does not always
+ -- work as desired. Register the protocol on the interface class instead.
+ -- The downside is that it would be a bad idea to put this into the global
+ -- configuration, so one has to make do with -X lua_script: for now.
+ local usb_bulk_dissectors = DissectorTable.get("usb.bulk")
+
+ -- For some reason the "unknown" class ID is sometimes 0xFF and sometimes
+ -- 0xFFFF. Register both to make it work all the time.
+ usb_bulk_dissectors:add(0xFF, p_lwla)
+ usb_bulk_dissectors:add(0xFFFF, p_lwla)
+end
projects / sigrok-util.git / commitdiff