git.rot13.org Git - goodfet/blob - client/USBInterface.py

   1 # USBInterface.py
   2 #
   3 # Contains class definition for USBInterface.
   4
   5 from USB import *
   6
   7 class USBInterface:
   8     name = "generic USB interface"
   9
  10     def __init__(self, interface_number, interface_alternate, interface_class,
  11             interface_subclass, interface_protocol, interface_string_index,
  12             verbose=0, endpoints=[], descriptors={}):
  13
  14         self.number = interface_number
  15         self.alternate = interface_alternate
  16         self.iclass = interface_class
  17         self.subclass = interface_subclass
  18         self.protocol = interface_protocol
  19         self.string_index = interface_string_index
  20
  21         self.endpoints = endpoints
  22         self.descriptors = descriptors
  23
  24         self.verbose = verbose
  25
  26         self.descriptors[USB.desc_type_interface] = self.get_descriptor
  27
  28         self.request_handlers = {
  29              6 : self.handle_get_descriptor_request,
  30             11 : self.handle_set_interface_request
  31         }
  32
  33         self.configuration = None
  34
  35         for e in self.endpoints:
  36             e.set_interface(self)
  37
  38         self.device_class = None
  39
  40     def set_configuration(self, config):
  41         self.configuration = config
  42
  43     # USB 2.0 specification, section 9.4.3 (p 281 of pdf)
  44     # HACK: blatant copypasta from USBDevice pains me deeply
  45     def handle_get_descriptor_request(self, req):
  46         dtype  = (req.value >> 8) & 0xff
  47         dindex = req.value & 0xff
  48         lang   = req.index
  49         n      = req.length
  50
  51         response = None
  52
  53         if self.verbose > 2:
  54             print(self.name, ("received GET_DESCRIPTOR req %d, index %d, " \
  55                     + "language 0x%04x, length %d") \
  56                     % (dtype, dindex, lang, n))
  57
  58         # TODO: handle KeyError
  59         response = self.descriptors[dtype]
  60         if callable(response):
  61             response = response(dindex)
  62
  63         if response:
  64             n = min(n, len(response))
  65             self.configuration.device.maxusb_app.send_on_endpoint(0, response[:n])
  66
  67             if self.verbose > 5:
  68                 print(self.name, "sent", n, "bytes in response")
  69
  70     def handle_set_interface_request(self, req):
  71         self.configuration.device.maxusb_app.stall_ep0()
  72
  73     # Table 9-12 of USB 2.0 spec (pdf page 296)
  74     def get_descriptor(self):
  75
  76         d = bytearray([
  77                 9,          # length of descriptor in bytes
  78                 4,          # descriptor type 4 == interface
  79                 self.number,
  80                 self.alternate,
  81                 len(self.endpoints),
  82                 self.iclass,
  83                 self.subclass,
  84                 self.protocol,
  85                 self.string_index
  86         ])
  87
  88         if self.iclass:
  89             iclass_desc_num = USB.interface_class_to_descriptor_type(self.iclass)
  90             if iclass_desc_num:
  91                 d += self.descriptors[iclass_desc_num]
  92
  93         for e in self.endpoints:
  94             d += e.get_descriptor()
  95
  96         return d
  97