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ice40: Validity check for LVDS IO

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Signed-off-by: David Shah <davey1576@gmail.com>
This commit is contained in:
David Shah 2018-09-24 15:14:28 +01:00
parent 9834b68041
commit d5d9fb27a6
4 changed files with 29 additions and 0 deletions
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2
ice40/arch.cc
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@ -975,6 +975,8 @@ void Arch::assignCellInfo(CellInfo *cell)
cell->lcInfo.inputCount++;
if (get_net_or_empty(cell, id_I3))
cell->lcInfo.inputCount++;
} else if (cell->type == id_SB_IO) {
cell->ioInfo.lvds = str_or_default(cell->params, id_IO_STANDARD, "SB_LVCMOS") == "SB_LVDS_INPUT";
}
}

21
ice40/arch_place.cc
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@ -139,6 +139,27 @@ bool Arch::isValidBelForCell(CellInfo *cell, BelId bel) const
}
}
}
Loc ioLoc = getBelLocation(bel);
Loc compLoc = ioLoc;
compLoc.z = 1 - compLoc.z;
// Check LVDS pairing
if (cell->ioInfo.lvds) {
// Check correct z and complement location is free
if (ioLoc.z != 0)
return false;
BelId compBel = getBelByLocation(compLoc);
CellInfo *compCell = getBoundBelCell(compBel);
if (compCell)
return false;
} else {
// Check LVDS IO is not placed at complement location
BelId compBel = getBelByLocation(compLoc);
CellInfo *compCell = getBoundBelCell(compBel);
if (compCell && compCell->ioInfo.lvds)
return false;
}
return getBelPackagePin(bel) != "";
} else if (cell->type == id_SB_GB) {
NPNR_ASSERT(cell->ports.at(id_GLOBAL_BUFFER_OUTPUT).net != nullptr);

5
ice40/archdefs.h
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@ -144,6 +144,11 @@ struct ArchCellInfo
int inputCount;
const NetInfo *clk, *cen, *sr;
} lcInfo;
struct
{
bool lvds;
// TODO: clk packing checks...
} ioInfo;
};
};

1
ice40/constids.inc
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@ -435,3 +435,4 @@ X(ICESTORM_SPRAM)
X(DFF_ENABLE)
X(CARRY_ENABLE)
X(NEG_CLK)
X(IO_STANDARD)