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frontend/crossbar: fill LiteDRAMDownConverter (to be tested)

This commit is contained in:
Florent Kermarrec 2016-05-24 08:34:14 +02:00
parent b76f7e6e07
commit f70e28beac
1 changed files with 57 additions and 3 deletions
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60
litedram/frontend/crossbar.py
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@ -10,6 +10,7 @@ from litedram.common import *
class LiteDRAMAsyncAdapter(Module): class LiteDRAMAsyncAdapter(Module):
# TODO: check cmd/wdata/rdata fifo depths
def __init__(self, port_from, port_to): def __init__(self, port_from, port_to):
assert port_from.aw == port_to.aw assert port_from.aw == port_to.aw
assert port_from.dw == port.to.dw assert port_from.dw == port.to.dw
@ -22,7 +23,8 @@ class LiteDRAMAsyncAdapter(Module):
# # # # # #
cmd_fifo = stream.AsyncFIFO([("we", 1), ("adr", aw)], 8) cmd_fifo = stream.AsyncFIFO([("we", 1), ("adr", aw)], 8)
cmd_fifo = ClockDomainsRenamer({"write": cd_from, "read": cd_to})(cmd_fifo) cmd_fifo = ClockDomainsRenamer({"write": cd_from,
"read": cd_to})(cmd_fifo)
self.submodules += cmd_fifo self.submodules += cmd_fifo
self.comb += [ self.comb += [
port_from.cmd.connect(cmd_fifo.sink), port_from.cmd.connect(cmd_fifo.sink),
@ -30,7 +32,8 @@ class LiteDRAMAsyncAdapter(Module):
] ]
wdata_fifo = stream.AsyncFIFO([("data", dw), ("we", dw//8)], 8) wdata_fifo = stream.AsyncFIFO([("data", dw), ("we", dw//8)], 8)
wdata_fifo = ClockDomainsRenamer({"write": cd_from, "read": cd_to})(wdata_fifo) wdata_fifo = ClockDomainsRenamer({"write": cd_from,
"read": cd_to})(wdata_fifo)
self.submodules += wdata_fifo self.submodules += wdata_fifo
self.comb += [ self.comb += [
port_from.wdata.connect(wdata_fifo.sink), port_from.wdata.connect(wdata_fifo.sink),
@ -38,7 +41,8 @@ class LiteDRAMAsyncAdapter(Module):
] ]
rdata_fifo = stream.AsyncFIFO([("data", dw)], 8) rdata_fifo = stream.AsyncFIFO([("data", dw)], 8)
rdata_fifo = ClockDomainsRenamer({"write": cd_to, "read": cd_from})(rdata_fifo) rdata_fifo = ClockDomainsRenamer({"write": cd_to,
"read": cd_from})(rdata_fifo)
self.submodules += rdata_fifo self.submodules += rdata_fifo
self.comb += [ self.comb += [
port_to.rdata.connect(rdata_fifo.sink), port_to.rdata.connect(rdata_fifo.sink),
@ -60,9 +64,59 @@ class _LiteDRAMDownConverter(Module):
def __init__(self, port_from, port_to): def __init__(self, port_from, port_to):
assert port_from.cd == port_to.cd assert port_from.cd == port_to.cd
assert port_from.dw > port_to.dw assert port_from.dw > port_to.dw
if port_from.dw % port_to.dw:
raise ValueError("Ratio must be an int")
# # # # # #
ratio = port_from.dw//port_to.dw
counter = Signal(max=ratio)
counter_reset = Signal()
counter_ce = Signal()
self.sync += \
If(counter_reset,
counter.eq(0)
).Elif(counter_ce,
counter.eq(counter + 1)
)
self.submodules.fsm = fsm = FSM(reset_state="IDLE")
fsm.act("IDLE",
counter_reset.eq(1),
If(port_from.cmd.valid,
NextState("ADAPT")
)
)
fsm.act("ADAPT",
port_to.cmd.valid.eq(1),
port_to.cmd.we.eq(port_from.cmd.we),
port_to.cmd.adr.eq(port_from.cmd.adr*ratio + counter),
If(port_to.cmd.ready,
counter_ce.eq(1),
If(counter == ratio - 1,
port_from.cmd.ready.eq(1)
NextState("IDLE")
)
)
)
wdata_converter = stream.StrideConverter(port_from.wdata.description,
port_to.wdata.descritpion)
self.submodules += wdata_converter
self.comb += [
port_from.wdata.connect(wdata_converter.sink),
wdata_converter.source.connect(port_to.wdata)
]
rdata_converter = stream.StrideConverter(port_to.rdata.description,
port_from.rdata.description)
self.submodules += rdata_converter
self.comb += [
port_to.rdata.connect(rdata_converter.sink),
rdata_converter.source.connect(port_from.rdata)
]
class _LiteDRAMUpConverter(Module): class _LiteDRAMUpConverter(Module):
"""LiteDRAM port UpConverter """LiteDRAM port UpConverter