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dma: style

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This commit is contained in:
Sebastien Bourdeauducq 2020-07-15 23:06:14 +08:00
parent 92405ffe91
commit b68cb137e5
1 changed files with 14 additions and 17 deletions
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31
src/gateware/dma.py
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@ -20,9 +20,6 @@ class AXIReader(Module):
# # #
ar = membus.ar
r = membus.r
eop_pending = Signal()
self.sync += [
If(self.sink.stb & self.sink.ack & self.sink.eop, eop_pending.eq(1)),
@ -30,14 +27,14 @@ class AXIReader(Module):
]
self.comb += [
ar.addr.eq(Cat(C(0, alignment_bits), self.sink.address)),
ar.id.eq(0), # Same ID for all transactions to forbid reordering.
ar.burst.eq(axi.Burst.incr.value),
ar.len.eq(AXI_BURST_LEN-1), # Number of transfers in burst (0->1 transfer, 1->2 transfers...).
ar.size.eq(log2_int(dw//8)), # Width of burst: 3 = 8 bytes = 64 bits.
ar.cache.eq(0xf),
ar.valid.eq(self.sink.stb & ~eop_pending),
self.sink.ack.eq(ar.ready & ~eop_pending)
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)
]
# UG585: "Large slave interface read acceptance capability in the range of 14 to 70 commands"
@ -45,17 +42,17 @@ class AXIReader(Module):
request_done = Signal()
reply_done = Signal()
self.comb += [
request_done.eq(ar.valid & ar.ready),
reply_done.eq(r.valid & r.ready & r.last)
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)
self.comb += [
self.source.stb.eq(r.valid),
r.ready.eq(self.source.ack),
self.source.data.eq(r.data),
self.source.stb.eq(membus.r.valid),
membus.r.ready.eq(self.source.ack),
self.source.data.eq(membus.r.data),
# Note that when eop_pending=1, no new transactions are made and inflight_cnt is no longer incremented
self.source.eop.eq(eop_pending & r.last & (inflight_cnt == 1))
self.source.eop.eq(eop_pending & membus.r.last & (inflight_cnt == 1))
]