- def _request(self, name, number=0, *, dir=None, xdr=None):
- """request a Resource (e.g. name="uart", number=0) which will
- return a data structure containing Records of all the pins.
-
- this override will also - automatically - create a JTAG Boundary Scan
- connection *without* any change to the actual Platform.request() API
- """
- pad_mgr = self.jtag.pad_mgr
- pad_mgr = self.jtag.pad_mgr
- padlookup = self.jtag.padlookup
- # okaaaay, bit of shenanigens going on: the important data structure
- # here is Resourcemanager._ports. requests add to _ports, which is
- # what needs redirecting. therefore what has to happen is to
- # capture the number of ports *before* the request. sigh.
- start_ports = len(self._ports)
- value = super().request(name, number, dir=dir, xdr=xdr)
- end_ports = len(self._ports)
-
- # now make a corresponding (duplicate) request to the pad manager
- # BUT, if it doesn't exist, don't sweat it: all it means is, the
- # application did not request Boundary Scan for that resource.
- pad_start_ports = len(pad_mgr._ports)
- try:
- pvalue = pad_mgr.request(name, number, dir=dir, xdr=xdr)
- except ResourceError:
- return value
- pad_end_ports = len(pad_mgr._ports)
-
- # ok now we have the lengths: now create a lookup between the pad
- # and the core, so that JTAG boundary scan can be inserted in between
- core = self._ports[start_ports:end_ports]
- pads = pad_mgr._ports[pad_start_ports:pad_end_ports]
- # oops if not the same numbers added. it's a duplicate. shouldn't happen
- assert len(core) == len(pads), "argh, resource manager error"
- print ("core", core)
- print ("pads", pads)
-
- # pad/core each return a list of tuples of (res, pin, port, attrs)
- for pad, core in zip(pads, core):
- # create a lookup on pin name to get at the hidden pad instance
- # this pin name will be handed to get_input, get_output etc.
- # and without the padlookup you can't find the (duplicate) pad.
- # note that self.padlookup and self.jtag.ios use the *exact* same
- # pin.name per pin
- pin = pad[1]
- corepin = core[1]
- if pin is None: continue # skip when pin is None
- assert corepin is not None # if pad was None, core should be too
- print ("iter", pad, pin.name)
- print ("existing pads", padlookup.keys())
- assert pin.name not in padlookup # no overwrites allowed!
- assert pin.name == corepin.name # has to be the same!
- padlookup[pin.name] = pad # store pad by pin name
-
- # now add the IO Shift Register. first identify the type
- # then request a JTAG IOConn. we can't wire it up (yet) because
- # we don't have a Module() instance. doh. that comes in get_input
- # and get_output etc. etc.
- iotype = resiotypes[pin.dir] # look up the C4M-JTAG IOType
- io = self.jtag.add_io(iotype=iotype, name=pin.name) # create IOConn
- self.jtag.ios[pin.name] = io # store IOConn Record by pin name
-
- # finally return the value just like ResourceManager.request()
- return value
-