Viaduct API for a hybrid between generic and full-custom arch

Signed-off-by: gatecat <gatecat@ds0.me>

1 files changed, 163 insertions, 0 deletions

diff --git a/generic/viaduct_helpers.cc b/generic/viaduct_helpers.cc
new file mode 100644
index 00000000..36bdd6be
--- /dev/null
+++ b/generic/viaduct_helpers.cc
@@ -0,0 +1,163 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2021  gatecat <gatecat@ds0.me>
+ *
+ *  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 "viaduct_helpers.h"
+#include "design_utils.h"
+#include "log.h"
+#include "nextpnr.h"
+#include "util.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+void ViaductHelpers::resize_ids(int x, int y)
+{
+    NPNR_ASSERT(x >= 0 && y >= 0 && x <= 20000 && y <= 20000);
+    while (int(x_ids.size()) <= x) {
+        IdString next = ctx->id(stringf("X%d", int(x_ids.size())));
+        x_ids.push_back(next);
+    }
+    while (int(y_ids.size()) <= y) {
+        IdString next = ctx->id(stringf("Y%d", int(y_ids.size())));
+        y_ids.push_back(next);
+    }
+}
+
+IdStringList ViaductHelpers::xy_id(int x, int y, IdString base)
+{
+    resize_ids(x, y);
+    std::array<IdString, 3> result{x_ids.at(x), y_ids.at(y), base};
+    return IdStringList(result);
+}
+
+IdStringList ViaductHelpers::xy_id(int x, int y, IdStringList base)
+{
+    resize_ids(x, y);
+    std::array<IdString, 2> prefix{x_ids.at(x), y_ids.at(y)};
+    return IdStringList::concat(IdStringList(prefix), base);
+}
+
+void ViaductHelpers::remove_nextpnr_iobs(const pool<CellTypePort> &top_ports)
+{
+    std::vector<IdString> to_remove;
+    for (auto &cell : ctx->cells) {
+        auto &ci = *cell.second;
+        if (!ci.type.in(ctx->id("$nextpnr_ibuf"), ctx->id("$nextpnr_obuf"), ctx->id("$nextpnr_iobuf")))
+            continue;
+        NetInfo *i = get_net_or_empty(&ci, ctx->id("I"));
+        if (i && i->driver.cell) {
+            if (!top_ports.count(CellTypePort(i->driver)))
+                log_error("Top-level port '%s' driven by illegal port %s.%s\n", ctx->nameOf(&ci),
+                          ctx->nameOf(i->driver.cell), ctx->nameOf(i->driver.port));
+        }
+        NetInfo *o = get_net_or_empty(&ci, ctx->id("O"));
+        if (o) {
+            for (auto &usr : o->users) {
+                if (!top_ports.count(CellTypePort(usr)))
+                    log_error("Top-level port '%s' driving illegal port %s.%s\n", ctx->nameOf(&ci),
+                              ctx->nameOf(usr.cell), ctx->nameOf(usr.port));
+            }
+        }
+        disconnect_port(ctx, &ci, ctx->id("I"));
+        disconnect_port(ctx, &ci, ctx->id("O"));
+        to_remove.push_back(ci.name);
+    }
+    for (IdString cell_name : to_remove)
+        ctx->cells.erase(cell_name);
+}
+
+int ViaductHelpers::constrain_cell_pairs(const pool<CellTypePort> &src_ports, const pool<CellTypePort> &sink_ports,
+                                         int delta_z)
+{
+    int constrained = 0;
+    for (auto &cell : ctx->cells) {
+        auto &ci = *cell.second;
+        if (ci.cluster != ClusterId())
+            continue; // don't constrain already-constrained cells
+        bool done = false;
+        for (auto &port : ci.ports) {
+            // look for starting source ports
+            if (port.second.type != PORT_OUT || !port.second.net)
+                continue;
+            if (!src_ports.count(CellTypePort(ci.type, port.first)))
+                continue;
+            for (auto &usr : port.second.net->users) {
+                if (!sink_ports.count(CellTypePort(usr)))
+                    continue;
+                if (usr.cell->cluster != ClusterId())
+                    continue;
+                // Add the constraint
+                ci.cluster = ci.name;
+                ci.constr_abs_z = false;
+                ci.constr_children.push_back(usr.cell);
+                usr.cell->cluster = ci.name;
+                usr.cell->constr_x = 0;
+                usr.cell->constr_y = 0;
+                usr.cell->constr_z = delta_z;
+                usr.cell->constr_abs_z = false;
+                ++constrained;
+                done = true;
+                break;
+            }
+            if (done)
+                break;
+        }
+    }
+    return constrained;
+}
+
+void ViaductHelpers::replace_constants(CellTypePort vcc_driver, CellTypePort gnd_driver,
+                                       const dict<IdString, Property> &vcc_params,
+                                       const dict<IdString, Property> &gnd_params)
+{
+    CellInfo *vcc_drv = ctx->createCell(ctx->id("$PACKER_VCC_DRV"), vcc_driver.cell_type);
+    vcc_drv->addOutput(vcc_driver.port);
+    for (auto &p : vcc_params)
+        vcc_drv->params[p.first] = p.second;
+
+    CellInfo *gnd_drv = ctx->createCell(ctx->id("$PACKER_GND_DRV"), gnd_driver.cell_type);
+    gnd_drv->addOutput(gnd_driver.port);
+    for (auto &p : gnd_params)
+        gnd_drv->params[p.first] = p.second;
+
+    NetInfo *vcc_net = ctx->createNet(ctx->id("$PACKER_VCC"));
+    NetInfo *gnd_net = ctx->createNet(ctx->id("$PACKER_GND"));
+
+    std::vector<IdString> trim_cells;
+    std::vector<IdString> trim_nets;
+    for (auto &net : ctx->nets) {
+        auto &ni = *net.second;
+        if (!ni.driver.cell)
+            continue;
+        if (ni.driver.cell->type != ctx->id("GND") && ni.driver.cell->type != ctx->id("VCC"))
+            continue;
+        NetInfo *replace = (ni.driver.cell->type == ctx->id("VCC")) ? vcc_net : gnd_net;
+        for (auto &usr : ni.users) {
+            usr.cell->ports.at(usr.port).net = replace;
+            replace->users.push_back(usr);
+        }
+        trim_cells.push_back(ni.driver.cell->name);
+        trim_nets.push_back(ni.name);
+    }
+    for (IdString cell_name : trim_cells)
+        ctx->cells.erase(cell_name);
+    for (IdString net_name : trim_nets)
+        ctx->nets.erase(net_name);
+}
+
+NEXTPNR_NAMESPACE_END