1#!/usr/bin/env python3
2#
3# Copyright (c) 2019 Intel Corporation.
4#
5# SPDX-License-Identifier: Apache-2.0
6"""
7Script to capture tracing data with USB backend.
8"""
9
10import usb.core
11import usb.util
12import argparse
13import sys
14
15def parse_args():
16    global args
17    parser = argparse.ArgumentParser(
18        description=__doc__,
19        formatter_class=argparse.RawDescriptionHelpFormatter, allow_abbrev=False)
20    parser.add_argument("-v", "--vendor_id", required=True,
21                        help="usb device vendor id")
22    parser.add_argument("-p", "--product_id", required=True,
23                        help="usb device product id")
24    parser.add_argument("-o", "--output", default='channel0_0',
25                        required=False, help="tracing data output file")
26    args = parser.parse_args()
27
28def main():
29    parse_args()
30    if args.vendor_id.isdecimal():
31        vendor_id = int(args.vendor_id)
32    else:
33        vendor_id = int(args.vendor_id, 16)
34
35    if args.product_id.isdecimal():
36        product_id = int(args.product_id)
37    else:
38        product_id = int(args.product_id, 16)
39
40    output_file = args.output
41
42    try:
43        usb_device = usb.core.find(idVendor=vendor_id, idProduct=product_id)
44    except Exception as e:
45        sys.exit("{}".format(e))
46
47    if usb_device is None:
48        sys.exit("No device found, check vendor_id and product_id")
49
50    if usb_device.is_kernel_driver_active(0):
51        try:
52            usb_device.detach_kernel_driver(0)
53        except usb.core.USBError as e:
54            sys.exit("{}".format(e))
55
56    # set the active configuration. With no arguments, the first
57    # configuration will be the active one
58    try:
59        usb_device.set_configuration()
60    except usb.core.USBError as e:
61        sys.exit("{}".format(e))
62
63    configuration = usb_device[0]
64    interface = configuration[(0, 0)]
65
66    # match the only IN endpoint
67    read_endpoint = usb.util.find_descriptor(interface, custom_match = \
68                                                lambda e: \
69                                                usb.util.endpoint_direction( \
70                                                    e.bEndpointAddress) == \
71                                                usb.util.ENDPOINT_IN)
72
73    # match the only OUT endpoint
74    write_endpoint = usb.util.find_descriptor(interface, custom_match = \
75                                                lambda e: \
76                                                usb.util.endpoint_direction( \
77                                                    e.bEndpointAddress) == \
78                                                usb.util.ENDPOINT_OUT)
79
80    usb.util.claim_interface(usb_device, interface)
81
82    #enable device tracing
83    write_endpoint.write('enable')
84
85    #try to read to avoid garbage mixed to useful stream data
86    buff = usb.util.create_buffer(8192)
87    read_endpoint.read(buff, 10000)
88
89    with open(output_file, "wb") as file_desc:
90        while True:
91            buff = usb.util.create_buffer(8192)
92            length = read_endpoint.read(buff, 100000)
93            for index in range(length):
94                file_desc.write(chr(buff[index]).encode('latin1'))
95
96    usb.util.release_interface(usb_device, interface)
97
98if __name__=="__main__":
99    try:
100        main()
101    except KeyboardInterrupt:
102        print('Data capture interrupted, data saved into {}'.format(args.output))
103        sys.exit(0)
104