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Fasm2bels fails due to orphan sink #1149

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acomodi opened this issue Nov 12, 2019 · 8 comments
Closed

Fasm2bels fails due to orphan sink #1149

acomodi opened this issue Nov 12, 2019 · 8 comments

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@acomodi
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acomodi commented Nov 12, 2019

While dealing with #1102, to debug the reasons of not having the OSERDES work on HW, I stumbled on an orphan_sink issue in fasm2bels. The error is the following:

// LIOI3_X0Y25 IOI_OLOGIC0_CLK 5816393
// LIOI3_X0Y25 IOI_OCLK_0 5816355
// LIOI3_X0Y25 IOI_LEAF_GCLK5 5816230
// HCLK_IOI3_X1Y26 HCLK_IOI_CK_IGCLK0 1918182
// HCLK_IOI3_X1Y26/HCLK_IOI_CK_IGCLK0 is connected to net via wire_pkey 1918166
// sink node 1322627 connected to source 1627198
// LIOI3_X0Y25/IOI_LEAF_GCLK5 is connected to net via wire_pkey 1918182
// sink node 1322683 connected to source 1627198
// LIOI3_X0Y25/IOI_OCLK_0 is connected to net via wire_pkey 5816230
// sink node 2020629 connected to source 1627198
// LIOI3_X0Y25/IOI_OLOGIC0_CLK is connected to net via wire_pkey 5816355
// sink node 2020667 connected to source 1627198
// LIOI3_X0Y25 IOI_OLOGIC0_CLKDIV 5816395
Traceback (most recent call last):
  File "/home/alessandro/projects/symbiflow/tmp/symbiflow-arch-defs/build/env/conda/lib/python3.7/runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "/home/alessandro/projects/symbiflow/tmp/symbiflow-arch-defs/build/env/conda/lib/python3.7/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "/home/alessandro/projects/symbiflow/tmp/symbiflow-arch-defs/xc7/fasm2bels/__main__.py", line 4, in <module>
    main()
  File "/home/alessandro/projects/symbiflow/tmp/symbiflow-arch-defs/xc7/fasm2bels/fasm2bels.py", line 296, in main
    top.make_routes(allow_orphan_sinks=args.allow_orphan_sinks)
  File "/home/alessandro/projects/symbiflow/tmp/symbiflow-arch-defs/xc7/fasm2bels/verilog_modeling.py", line 1381, in make_routes
    net_map=self.net_map,
  File "/home/alessandro/projects/symbiflow/tmp/symbiflow-arch-defs/xc7/fasm2bels/make_routes.py", line 700, in make_routes
    allow_orphan_sinks=allow_orphan_sinks
  File "/home/alessandro/projects/symbiflow/tmp/symbiflow-arch-defs/xc7/fasm2bels/make_routes.py", line 610, in expand_sink
    assert False, (sink_node_pkey, tile_name, wire_name, sink_wire_pkey)
AssertionError: (2020669, 'LIOI3_X0Y25', 'IOI_OLOGIC0_CLKDIV', 5816395)

By examining both the fasm file and the routing graph I have double-checked that the route is actually there.
expand_node should be able to find a route to the first sink which is connected to a source, as it happens for the LIOI3_X0Y25 IOI_OLOGIC0_CLK for which the tool can find the connections to the HCLK_IOI_CK_IGCLK0 that already has a connection.
Instead, the tool seems to be unable to find very similar routes for the OLOGIC0_CLKDIV pip.

The problem may be that expand_node cannot find an active upstream connected pip to OLOGIC0_CLKDIV, and this seems to be a possible bug in make_routes as in the top.fasm file the connection is there (to IOI_LEAF_GCLK1):

...
LIOI3_X0Y25.ILOGIC_Y1.ZINV_D
LIOI3_X0Y25.IOI_OCLK_0.IOI_LEAF_GCLK5
LIOI3_X0Y25.IOI_OLOGIC0_CLKDIV.IOI_LEAF_GCLK1
...
@acomodi acomodi changed the title Fasm2bels fails due to orphan_sink Fasm2bels fails due to orphan sink Nov 12, 2019
@acomodi
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acomodi commented Nov 12, 2019

@litghost FYI

@acomodi
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acomodi commented Nov 12, 2019 •
edited
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To reproduce the error is enough to run the vivado_load_dcp target of one of the oserdes tests of #1102

@litghost
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litghost commented Nov 12, 2019 •
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Any chance there is a swapping of Y0 and Y1? That might be causing the problem.

@acomodi
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acomodi commented Nov 12, 2019

I Have to check it, but I doubt it as I think also the OLOGIC0_CLK would fail as well

@litghost
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OLOGIC0_CLK is a ppip, so it would not have failed. OLOGIC0_CLKDIV does have routing choices, so it is not a ppip.

@acomodi
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acomodi commented Nov 13, 2019 •
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So, the Y locations should be correct. I am debugging fasm2bels and a strange thing happens during the computation of the maybe_active_pips:

...
SINK WIRE:  IOI_LEAF_GCLK1
SOURCE WIRE:  IOI_OCLK_0
SINK WIRE:  IOI_LEAF_GCLK5
NOT TAKEN SOURCE WIRE:  IOI_OLOGIC0_CLKDIV
...

IOI_OLOGIC0_CLKDIV seems not to be present in the wire_in_tile table.

@acomodi
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acomodi commented Nov 14, 2019

I have discovered the issue. It is related with the usage of non-canonical physical tiles, for which the IOI_OLOGIC0_CLKDIV source wire could not be found as the tile_type_pkey did not match any entry in the db.

I have a fix for that in a68cc81

@acomodi
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acomodi commented Nov 18, 2019

Solved in #1102. Closing

@acomodi acomodi closed this as completed Nov 18, 2019
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@litghost @acomodi