artiq-zynq/src/gateware/dma.py

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from migen import *
from migen.genlib.fsm import FSM
from misoc.interconnect.csr import *
from misoc.interconnect import stream
from migen_axi.interconnect import axi
from artiq.gateware.rtio.dma import RawSlicer, RecordConverter, RecordSlicer, TimeOffset, CRIMaster
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import endianness
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AXI_BURST_LEN = 16
class AXIReader(Module):
def __init__(self, membus):
aw = len(membus.ar.addr)
dw = len(membus.r.data)
alignment_bits = log2_int(AXI_BURST_LEN*dw//8)
self.sink = stream.Endpoint([("address", aw - alignment_bits)])
self.source = stream.Endpoint([("data", dw)])
# # #
eop_pending = Signal()
self.sync += [
If(self.sink.stb & self.sink.ack & self.sink.eop, eop_pending.eq(1)),
If(self.source.stb & self.source.ack & self.source.eop, eop_pending.eq(0)),
]
self.comb += [
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membus.ar.addr.eq(Cat(C(0, alignment_bits), self.sink.address)),
membus.ar.id.eq(0), # Same ID for all transactions to forbid reordering.
membus.ar.burst.eq(axi.Burst.incr.value),
membus.ar.len.eq(AXI_BURST_LEN-1), # Number of transfers in burst (0->1 transfer, 1->2 transfers...).
membus.ar.size.eq(log2_int(dw//8)), # Width of burst: 3 = 8 bytes = 64 bits.
membus.ar.cache.eq(0xf),
membus.ar.valid.eq(self.sink.stb & ~eop_pending),
self.sink.ack.eq(membus.ar.ready & ~eop_pending)
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]
# UG585: "Large slave interface read acceptance capability in the range of 14 to 70 commands"
inflight_cnt = Signal(max=128)
request_done = Signal()
reply_done = Signal()
self.comb += [
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request_done.eq(membus.ar.valid & membus.ar.ready),
reply_done.eq(membus.r.valid & membus.r.ready & membus.r.last)
]
self.sync += inflight_cnt.eq(inflight_cnt + request_done - reply_done)
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self.comb += [
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self.source.stb.eq(membus.r.valid),
membus.r.ready.eq(self.source.ack),
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self.source.data.eq(endianness.convert_signal(membus.r.data)),
# Note that when eop_pending=1, no new transactions are made and inflight_cnt is no longer incremented
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self.source.eop.eq(eop_pending & membus.r.last & (inflight_cnt == 1))
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]
class DMAReader(Module, AutoCSR):
def __init__(self, membus, enable):
aw = len(membus.ar.addr)
alignment_bits = log2_int(AXI_BURST_LEN*len(membus.r.data)//8)
self.submodules.wb_reader = AXIReader(membus)
self.source = self.wb_reader.source
# All numbers in bytes
self.base_address = CSRStorage(aw, alignment_bits=alignment_bits)
# # #
enable_r = Signal()
address = self.wb_reader.sink
assert len(address.address) == len(self.base_address.storage)
self.sync += [
enable_r.eq(enable),
If(enable & ~enable_r,
address.address.eq(self.base_address.storage),
address.eop.eq(0),
address.stb.eq(1),
),
If(address.stb & address.ack,
If(address.eop,
address.stb.eq(0)
).Else(
address.address.eq(address.address + 1),
If(~enable, address.eop.eq(1))
)
)
]
class DMA(Module):
def __init__(self, membus):
self.enable = CSR()
flow_enable = Signal()
self.submodules.dma = DMAReader(membus, flow_enable)
self.submodules.slicer = RecordSlicer(len(membus.r.data))
self.submodules.time_offset = TimeOffset()
self.submodules.cri_master = CRIMaster()
self.cri = self.cri_master.cri
self.comb += [
self.dma.source.connect(self.slicer.sink),
self.slicer.source.connect(self.time_offset.sink),
self.time_offset.source.connect(self.cri_master.sink)
]
fsm = FSM(reset_state="IDLE")
self.submodules += fsm
fsm.act("IDLE",
If(self.enable.re, NextState("FLOWING"))
)
fsm.act("FLOWING",
self.enable.w.eq(1),
flow_enable.eq(1),
If(self.slicer.end_marker_found,
NextState("FLUSH")
)
)
fsm.act("FLUSH",
self.enable.w.eq(1),
self.slicer.flush.eq(1),
NextState("WAIT_EOP")
)
fsm.act("WAIT_EOP",
self.enable.w.eq(1),
If(self.cri_master.sink.stb & self.cri_master.sink.ack & self.cri_master.sink.eop,
NextState("WAIT_CRI_MASTER")
)
)
fsm.act("WAIT_CRI_MASTER",
self.enable.w.eq(1),
If(~self.cri_master.busy, NextState("IDLE"))
)
def get_csrs(self):
return ([self.enable] +
self.dma.get_csrs() + self.time_offset.get_csrs() +
self.cri_master.get_csrs())