ice40: Adding a placement validity checker

Signed-off-by: David Shah <davey1576@gmail.com>

1 files changed, 89 insertions, 0 deletions

diff --git a/ice40/arch_place.cc b/ice40/arch_place.cc
new file mode 100644
index 00000000..2367d981
--- /dev/null
+++ b/ice40/arch_place.cc
@@ -0,0 +1,89 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Clifford Wolf <clifford@clifford.at>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include "arch_place.h"
+
+static bool logicCellsCompatible(const std::vector<const CellInfo *> &cells)
+{
+    bool dffs_exist = false, dffs_neg = false;
+    const NetInfo *cen = nullptr, *clk = nullptr, *sr = nullptr;
+    std::unordered_set<const NetInfo *> locals;
+
+    for (auto cell : cells) {
+        if (std::stoi(cell->params.at("DFF_ENABLE"))) {
+            if (!dffs_exist) {
+                dffs_exist = true;
+                cen = cell->ports.at("CEN").net;
+                clk = cell->ports.at("CLK").net;
+                sr = cell->ports.at("SR").net;
+
+                locals.insert(cen);
+                locals.insert(clk);
+                locals.insert(sr);
+
+                if (std::stoi(cell->params.at("NEG_CLK"))) {
+                    dffs_neg = true;
+                }
+            } else {
+                if (cen != cell->ports.at("CEN").net)
+                    return false;
+                if (clk == cell->ports.at("CLK").net)
+                    return false;
+                if (sr != cell->ports.at("SR").net)
+                    return false;
+                if (dffs_neg != bool(std::stoi(cell->params.at("NEG_CLK"))))
+                    return false;
+            }
+        }
+
+        locals.insert(cell->ports.at("I0").net);
+        locals.insert(cell->ports.at("I1").net);
+        locals.insert(cell->ports.at("I2").net);
+        locals.insert(cell->ports.at("I3").net);
+    }
+
+    locals.erase(nullptr); // disconnected signals don't use local tracks
+
+    return locals.size() <= 32;
+}
+
+bool isValidBelForCell(Design *design, CellInfo *cell, BelId bel)
+{
+    const Chip &chip = design->chip;
+    if (cell->type == "ICESTORM_LC") {
+        assert(chip.getBelType(bel) == TYPE_ICESTORM_LC);
+
+        std::vector<const CellInfo *> cells;
+
+        for (auto bel_other : chip.getBelsAtSameTile(bel)) {
+            IdString cell_other = chip.getBelCell(bel_other, false);
+            if (cell_other != IdString()) {
+                const CellInfo *ci_other = design->cells[cell_other];
+                cells.push_back(ci_other);
+            }
+        }
+
+        cells.push_back(cell);
+        return logicCellsCompatible(cells);
+
+    } else {
+        // TODO: IO cell clock checks
+        return true;
+    }
+}