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frontend/adapter/LiteDRAMNativePortDownConverter: Do early ack of user cmd. 

To better decouple cmd/data paths in user logic.
This commit is contained in:
Florent Kermarrec 2023-05-31 16:52:38 +02:00 committed by Hans Baier
parent 5e7ba4ee71
commit ed1e569e29
1 changed files with 12 additions and 7 deletions
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19
litedram/frontend/adapter.py
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@ -81,23 +81,28 @@ class LiteDRAMNativePortDownConverter(Module):
ratio = port_from.data_width//port_to.data_width
mode = port_from.mode
count = Signal(max=ratio)
cmd_count = Signal(max=ratio)
cmd_addr = Signal(len(port_from.cmd.addr))
cmd_we = Signal()
self.submodules.fsm = fsm = FSM(reset_state="IDLE")
fsm.act("IDLE",
NextValue(count, 0),
port_from.cmd.ready.eq(1),
If(port_from.cmd.valid,
NextValue(cmd_count, 0),
NextValue(cmd_addr, port_from.cmd.addr),
NextValue(cmd_we, port_from.cmd.we),
NextState("CONVERT")
)
)
fsm.act("CONVERT",
port_to.cmd.valid.eq(1),
port_to.cmd.we.eq(port_from.cmd.we),
port_to.cmd.addr.eq(port_from.cmd.addr*ratio + count),
port_to.cmd.we.eq(cmd_we),
port_to.cmd.addr.eq(cmd_addr*ratio + cmd_count),
If(port_to.cmd.ready,
NextValue(count, count + 1),
If(count == (ratio - 1),
port_from.cmd.ready.eq(1),
NextValue(cmd_count, cmd_count + 1),
If(cmd_count == (ratio - 1),
NextState("IDLE")
)
)