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frontend/avalon: Add back cmd_fifo (and always go through it).

This commit is contained in:
Florent Kermarrec 2023-06-01 13:07:09 +02:00
parent 3d016b2ad5
commit ec6d2467c7
1 changed files with 19 additions and 13 deletions
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32
litedram/frontend/avalon.py
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@ -61,41 +61,47 @@ class LiteDRAMAvalonMM2Native(LiteXModule):
]
self.wdata_fifo = wdata_fifo = stream.SyncFIFO(wdata_layout, max_burst_length)
# Cmd FIFO.
# ---------
cmd_layout = [("addr", port.address_width), ("we", 1)]
self.cmd_fifo = cmd_fifo = stream.SyncFIFO(cmd_layout, max_burst_length)
# Control-Path.
# -------------
self.fsm = fsm = FSM(reset_state="SINGLE-ACCESS")
fsm.act("SINGLE-ACCESS",
avalon.waitrequest.eq(1),
port.cmd.addr.eq(avalon.address - address_offset),
port.cmd.we.eq(avalon.write),
port.cmd.valid.eq(avalon.read | (avalon.write & wdata_fifo.sink.ready)),
port.cmd.last.eq(avalon.burstcount <= 1),
If(port.cmd.valid & port.cmd.ready,
cmd_fifo.sink.valid.eq(avalon.read | (avalon.write & wdata_fifo.sink.ready)),
cmd_fifo.sink.last.eq(avalon.burstcount <= 1),
cmd_fifo.sink.we.eq(avalon.write),
cmd_fifo.sink.addr.eq(avalon.address - address_offset),
If(cmd_fifo.sink.valid & cmd_fifo.sink.ready,
avalon.waitrequest.eq(0),
# If access is a burst, continue it in BURST-ACCESS.
If(~port.cmd.last,
If(~cmd_fifo.sink.last,
NextValue(burst_count, avalon.burstcount - 1),
NextValue(burst_read, avalon.read),
NextValue(burst_address, port.cmd.addr + burst_increment),
NextValue(burst_address, cmd_fifo.sink.addr + burst_increment),
NextState("BURST-ACCESS")
)
)
)
fsm.act("BURST-ACCESS",
avalon.waitrequest.eq(1),
port.cmd.addr.eq(burst_address),
port.cmd.we.eq(avalon.write),
port.cmd.valid.eq(burst_read | (avalon.write & wdata_fifo.sink.ready)),
port.cmd.last.eq(burst_count == 1),
If(port.cmd.valid & port.cmd.ready,
cmd_fifo.sink.valid.eq(burst_read | (avalon.write & wdata_fifo.sink.ready)),
cmd_fifo.sink.last.eq(burst_count == 1),
cmd_fifo.sink.we.eq(avalon.write),
cmd_fifo.sink.addr.eq(burst_address),
If(cmd_fifo.sink.valid & cmd_fifo.sink.ready,
avalon.waitrequest.eq(~avalon.write),
NextValue(burst_count, burst_count - 1),
NextValue(burst_address, burst_address + burst_increment),
If(port.cmd.last,
If(cmd_fifo.sink.last,
NextState("SINGLE-ACCESS")
)
)
)
self.comb += cmd_fifo.source.connect(port.cmd, keep={"valid", "ready", "last", "we", "addr"})
# Write Data-path.
# ----------------