litex/migen/bank/csrgen.py

81 lines
2.4 KiB
Python

from migen.util.misc import xdir
from migen.fhdl.std import *
from migen.bus import csr
from migen.bank.bank import GenericBank
class Bank(GenericBank):
def __init__(self, description, address=0, bus=None):
if bus is None:
bus = csr.Interface()
self.bus = bus
###
GenericBank.__init__(self, description, flen(self.bus.dat_w))
sel = Signal()
self.comb += sel.eq(self.bus.adr[9:] == address)
for i, c in enumerate(self.simple_csrs):
self.comb += [
c.r.eq(self.bus.dat_w[:c.size]),
c.re.eq(sel & \
self.bus.we & \
(self.bus.adr[:self.decode_bits] == i))
]
brcases = dict((i, self.bus.dat_r.eq(c.w)) for i, c in enumerate(self.simple_csrs))
self.sync += [
self.bus.dat_r.eq(0),
If(sel, Case(self.bus.adr[:self.decode_bits], brcases))
]
# address_map(name, memory) returns the CSR offset at which to map
# the CSR object (register bank or memory).
# If memory=None, the object is the register bank of object source.name.
# Otherwise, it is a memory object belonging to source.name.
# address_map is called exactly once for each object at each call to
# scan(), so it can have side effects.
class BankArray(Module):
def __init__(self, source, address_map, *ifargs, **ifkwargs):
self.source = source
self.address_map = address_map
self.scan(ifargs, ifkwargs)
def scan(self, ifargs, ifkwargs):
self.banks = []
self.srams = []
for name, obj in xdir(self.source, True):
if hasattr(obj, "get_csrs"):
csrs = obj.get_csrs()
else:
csrs = []
if hasattr(obj, "get_memories"):
memories = obj.get_memories()
for memory in memories:
mapaddr = self.address_map(name, memory)
if mapaddr is None:
continue
sram_bus = csr.Interface(*ifargs, **ifkwargs)
mmap = csr.SRAM(memory, mapaddr, bus=sram_bus)
self.submodules += mmap
csrs += mmap.get_csrs()
self.srams.append((name, memory, mapaddr, mmap))
if csrs:
mapaddr = self.address_map(name, None)
if mapaddr is None:
continue
bank_bus = csr.Interface(*ifargs, **ifkwargs)
rmap = Bank(csrs, mapaddr, bus=bank_bus)
self.submodules += rmap
self.banks.append((name, csrs, mapaddr, rmap))
def get_rmaps(self):
return [rmap for name, csrs, mapaddr, rmap in self.banks]
def get_mmaps(self):
return [mmap for name, memory, mapaddr, mmap in self.srams]
def get_buses(self):
return [i.bus for i in self.get_rmaps() + self.get_mmaps()]