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build.res: allow requesting raw ports, with dir="-".

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This provides an escape hatch for the case where the nMigen platform
code is not flexible enough, and a IO buffer primitive needs to be
instantiated directly.
This commit is contained in:
whitequark 2019-06-03 03:17:20 +00:00
parent c30617fc05
commit cd6488c782
2 changed files with 52 additions and 24 deletions
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51
nmigen/build/res.py
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@ -84,13 +84,14 @@ class ConstraintManager:
dir = subsignal.io[0].dir
if xdr is None:
xdr = 1
if dir not in ("i", "o", "io"):
raise TypeError("Direction must be one of \"i\", \"o\" or \"io\", not {!r}"
if dir not in ("i", "o", "io", "-"):
raise TypeError("Direction must be one of \"i\", \"o\", \"io\", or \"-\", "
"not {!r}"
.format(dir))
if subsignal.io[0].dir != "io" and dir != subsignal.io[0].dir:
if dir != subsignal.io[0].dir and not (subsignal.io[0].dir == "io" or dir == "-"):
raise ValueError("Direction of {!r} cannot be changed from \"{}\" to \"{}\"; "
"direction can be changed from \"io\" to \"i\" or from \"io\""
"to \"o\""
"direction can be changed from \"io\" to \"i\", from \"io\""
"to \"o\", or from anything to \"-\""
.format(subsignal.io[0], subsignal.io[0].dir, dir))
if not isinstance(xdr, int) or xdr < 1:
raise ValueError("Data rate of {!r} must be a positive integer, not {!r}"
@ -109,14 +110,19 @@ class ConstraintManager:
elif isinstance(subsignal.io[0], (Pins, DiffPairs)):
phys = subsignal.io[0]
pin = Pin(len(phys), dir, xdr, name=name)
if isinstance(phys, Pins):
port = Signal(pin.width, name="{}__io".format(pin.name))
port = Record([("io", len(phys))], name=name)
if isinstance(phys, DiffPairs):
port = (Signal(pin.width, name="{}__p".format(pin.name)),
Signal(pin.width, name="{}__n".format(pin.name)))
self._ports.append((subsignal, pin, port))
return pin
port = Record([("p", len(phys)),
("n", len(phys))], name=name)
if dir == "-":
self._ports.append((subsignal, None, port))
return port
else:
pin = Pin(len(phys), dir, xdr, name=name)
self._ports.append((subsignal, pin, port))
return pin
else:
assert False # :nocov:
@ -128,38 +134,39 @@ class ConstraintManager:
def iter_single_ended_pins(self):
for resource, pin, port in self._ports:
if pin is None:
continue
if isinstance(resource.io[0], Pins):
yield pin, port, resource.extras
yield pin, port.io, resource.extras
def iter_differential_pins(self):
for resource, pin, port in self._ports:
if pin is None:
continue
if isinstance(resource.io[0], DiffPairs):
p_port, n_port = port
yield pin, p_port, n_port, resource.extras
yield pin, port.p, port.n, resource.extras
def iter_ports(self):
for resource, pin, port in self._ports:
if isinstance(resource.io[0], Pins):
yield port
yield port.io
elif isinstance(resource.io[0], DiffPairs):
p_port, n_port = port
yield p_port
yield n_port
yield port.p
yield port.n
else:
assert False
def iter_port_constraints(self, diff_pins="pn"):
for resource, pin, port in self._ports:
if isinstance(resource.io[0], Pins):
yield port.name, resource.io[0].names, resource.extras
yield port.io.name, resource.io[0].names, resource.extras
elif isinstance(resource.io[0], DiffPairs):
p_port, n_port = port
# On some FPGAs like iCE40, only one pin out of two in a differential pair may be
# constrained. The other has to be completely disconnected.
if "p" in diff_pins:
yield p_port.name, resource.io[0].p.names, resource.extras
yield port.p.name, resource.io[0].p.names, resource.extras
if "n" in diff_pins:
yield n_port.name, resource.io[0].n.names, resource.extras
yield port.n.name, resource.io[0].n.names, resource.extras
else:
assert False