1 files changed, 296 insertions, 0 deletions
diff --git a/machxo2/pack.cc b/machxo2/pack.cc
new file mode 100644
index 00000000..5a6cd97b
--- /dev/null
+++ b/machxo2/pack.cc
@@ -0,0 +1,296 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018-19  David Shah <david@symbioticeda.com>
+ *  Copyright (C) 2021  William D. Jones <wjones@wdj-consulting.com>
+ *
+ *  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 <algorithm>
+#include <iterator>
+#include <unordered_set>
+#include "cells.h"
+#include "design_utils.h"
+#include "log.h"
+#include "util.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+// Pack LUTs and LUT-FF pairs
+static void pack_lut_lutffs(Context *ctx)
+{
+    log_info("Packing LUT-FFs..\n");
+
+    std::unordered_set<IdString> packed_cells;
+    std::vector<std::unique_ptr<CellInfo>> new_cells;
+    for (auto cell : sorted(ctx->cells)) {
+        CellInfo *ci = cell.second;
+        if (ctx->verbose)
+            log_info("cell '%s' is of type '%s'\n", ci->name.c_str(ctx), ci->type.c_str(ctx));
+        if (is_lut(ctx, ci)) {
+            std::unique_ptr<CellInfo> packed = create_machxo2_cell(ctx, id_FACADE_SLICE, ci->name.str(ctx) + "_LC");
+            std::copy(ci->attrs.begin(), ci->attrs.end(), std::inserter(packed->attrs, packed->attrs.begin()));
+
+            packed_cells.insert(ci->name);
+            if (ctx->verbose)
+                log_info("packed cell %s into %s\n", ci->name.c_str(ctx), packed->name.c_str(ctx));
+            // See if we can pack into a DFF. Both LUT4 and FF outputs are
+            // available for a given slice, so we can pack a FF even if the
+            // LUT4 drives more than one FF.
+            NetInfo *o = ci->ports.at(id_Z).net;
+            CellInfo *dff = net_only_drives(ctx, o, is_ff, id_DI, false);
+            auto lut_bel = ci->attrs.find(ctx->id("BEL"));
+            bool packed_dff = false;
+
+            if (dff) {
+                if (ctx->verbose)
+                    log_info("found attached dff %s\n", dff->name.c_str(ctx));
+                auto dff_bel = dff->attrs.find(ctx->id("BEL"));
+                if (lut_bel != ci->attrs.end() && dff_bel != dff->attrs.end() && lut_bel->second != dff_bel->second) {
+                    // Locations don't match, can't pack
+                } else {
+                    lut_to_lc(ctx, ci, packed.get(), false);
+                    dff_to_lc(ctx, dff, packed.get(), false);
+                    if (dff_bel != dff->attrs.end())
+                        packed->attrs[ctx->id("BEL")] = dff_bel->second;
+                    packed_cells.insert(dff->name);
+                    if (ctx->verbose)
+                        log_info("packed cell %s into %s\n", dff->name.c_str(ctx), packed->name.c_str(ctx));
+                    packed_dff = true;
+                }
+            }
+            if (!packed_dff) {
+                lut_to_lc(ctx, ci, packed.get(), true);
+            }
+            new_cells.push_back(std::move(packed));
+        }
+    }
+
+    for (auto pcell : packed_cells) {
+        ctx->cells.erase(pcell);
+    }
+    for (auto &ncell : new_cells) {
+        ctx->cells[ncell->name] = std::move(ncell);
+    }
+}
+
+static void pack_remaining_ffs(Context *ctx)
+{
+    log_info("Packing remaining FFs..\n");
+
+    std::unordered_set<IdString> packed_cells;
+    std::vector<std::unique_ptr<CellInfo>> new_cells;
+
+    for (auto cell : sorted(ctx->cells)) {
+        CellInfo *ci = cell.second;
+
+        if (is_ff(ctx, ci)) {
+            if (ctx->verbose)
+                log_info("cell '%s' of type '%s remains unpacked'\n", ci->name.c_str(ctx), ci->type.c_str(ctx));
+
+            std::unique_ptr<CellInfo> packed = create_machxo2_cell(ctx, id_FACADE_SLICE, ci->name.str(ctx) + "_LC");
+            std::copy(ci->attrs.begin(), ci->attrs.end(), std::inserter(packed->attrs, packed->attrs.begin()));
+
+            auto dff_bel = ci->attrs.find(ctx->id("BEL"));
+            dff_to_lc(ctx, ci, packed.get(), false);
+            if (dff_bel != ci->attrs.end())
+                packed->attrs[ctx->id("BEL")] = dff_bel->second;
+            packed_cells.insert(ci->name);
+            if (ctx->verbose)
+                log_info("packed cell %s into %s\n", ci->name.c_str(ctx), packed->name.c_str(ctx));
+
+            new_cells.push_back(std::move(packed));
+        }
+    }
+
+    for (auto pcell : packed_cells) {
+        ctx->cells.erase(pcell);
+    }
+    for (auto &ncell : new_cells) {
+        ctx->cells[ncell->name] = std::move(ncell);
+    }
+}
+
+// Merge a net into a constant net
+static void set_net_constant(Context *ctx, NetInfo *orig, NetInfo *constnet, bool constval)
+{
+    (void)constval;
+
+    std::unordered_set<IdString> packed_cells;
+    std::vector<std::unique_ptr<CellInfo>> new_cells;
+
+    orig->driver.cell = nullptr;
+    for (auto user : orig->users) {
+        if (user.cell != nullptr) {
+            CellInfo *uc = user.cell;
+            if (ctx->verbose)
+                log_info("%s user %s\n", orig->name.c_str(ctx), uc->name.c_str(ctx));
+
+            if (uc->type == id_FACADE_FF && user.port == id_DI) {
+                log_info("FACADE_FF %s is driven by a constant\n", uc->name.c_str(ctx));
+
+                std::unique_ptr<CellInfo> lc = create_machxo2_cell(ctx, id_FACADE_SLICE, uc->name.str(ctx) + "_CONST");
+                std::copy(uc->attrs.begin(), uc->attrs.end(), std::inserter(lc->attrs, lc->attrs.begin()));
+
+                dff_to_lc(ctx, uc, lc.get(), true);
+                packed_cells.insert(uc->name);
+
+                lc->ports[id_A0].net = constnet;
+                user.cell = lc.get();
+                user.port = id_A0;
+
+                new_cells.push_back(std::move(lc));
+            } else {
+                uc->ports[user.port].net = constnet;
+            }
+
+            constnet->users.push_back(user);
+        }
+    }
+    orig->users.clear();
+
+    for (auto pcell : packed_cells) {
+        ctx->cells.erase(pcell);
+    }
+    for (auto &ncell : new_cells) {
+        ctx->cells[ncell->name] = std::move(ncell);
+    }
+}
+
+// Pack constants (based on simple implementation in generic).
+// VCC/GND cells provided by nextpnr automatically.
+static void pack_constants(Context *ctx)
+{
+    log_info("Packing constants..\n");
+
+    std::unique_ptr<CellInfo> const_cell = create_machxo2_cell(ctx, id_FACADE_SLICE, "$PACKER_CONST");
+    const_cell->params[id_LUT0_INITVAL] = Property(0, 16);
+    const_cell->params[id_LUT1_INITVAL] = Property(0xFFFF, 16);
+
+    std::unique_ptr<NetInfo> gnd_net = std::unique_ptr<NetInfo>(new NetInfo);
+    gnd_net->name = ctx->id("$PACKER_GND_NET");
+    gnd_net->driver.cell = const_cell.get();
+    gnd_net->driver.port = id_F0;
+    const_cell->ports.at(id_F0).net = gnd_net.get();
+
+    std::unique_ptr<NetInfo> vcc_net = std::unique_ptr<NetInfo>(new NetInfo);
+    vcc_net->name = ctx->id("$PACKER_VCC_NET");
+    vcc_net->driver.cell = const_cell.get();
+    vcc_net->driver.port = id_F1;
+    const_cell->ports.at(id_F1).net = vcc_net.get();
+
+    std::vector<IdString> dead_nets;
+
+    for (auto net : sorted(ctx->nets)) {
+        NetInfo *ni = net.second;
+        if (ni->driver.cell != nullptr && ni->driver.cell->type == ctx->id("GND")) {
+            IdString drv_cell = ni->driver.cell->name;
+            set_net_constant(ctx, ni, gnd_net.get(), false);
+            dead_nets.push_back(net.first);
+            ctx->cells.erase(drv_cell);
+        } else if (ni->driver.cell != nullptr && ni->driver.cell->type == ctx->id("VCC")) {
+            IdString drv_cell = ni->driver.cell->name;
+            set_net_constant(ctx, ni, vcc_net.get(), true);
+            dead_nets.push_back(net.first);
+            ctx->cells.erase(drv_cell);
+        }
+    }
+
+    ctx->cells[const_cell->name] = std::move(const_cell);
+    ctx->nets[gnd_net->name] = std::move(gnd_net);
+    ctx->nets[vcc_net->name] = std::move(vcc_net);
+
+    for (auto dn : dead_nets) {
+        ctx->nets.erase(dn);
+    }
+}
+
+static bool is_nextpnr_iob(Context *ctx, CellInfo *cell)
+{
+    return cell->type == ctx->id("$nextpnr_ibuf") || cell->type == ctx->id("$nextpnr_obuf") ||
+           cell->type == ctx->id("$nextpnr_iobuf");
+}
+
+static bool is_facade_iob(const Context *ctx, const CellInfo *cell) { return cell->type == id_FACADE_IO; }
+
+// Pack IO buffers- Right now, all this does is remove $nextpnr_[io]buf cells.
+// User is expected to manually instantiate FACADE_IO with BEL/IO_TYPE
+// attributes.
+static void pack_io(Context *ctx)
+{
+    std::unordered_set<IdString> packed_cells;
+
+    log_info("Packing IOs..\n");
+
+    for (auto cell : sorted(ctx->cells)) {
+        CellInfo *ci = cell.second;
+        if (is_nextpnr_iob(ctx, ci)) {
+            for (auto &p : ci->ports)
+                disconnect_port(ctx, ci, p.first);
+            packed_cells.insert(ci->name);
+        } else if (is_facade_iob(ctx, ci)) {
+            // If FACADE_IO has LOC attribute, convert the LOC (pin) to a BEL
+            // attribute and place FACADE_IO at resulting BEL location. A BEL
+            // attribute already on a FACADE_IO is an error. Attributes on
+            // the pin attached to the PAD of FACADE_IO are ignored by this
+            // packing phase.
+            auto loc_attr_cell = ci->attrs.find(ctx->id("LOC"));
+            auto bel_attr_cell = ci->attrs.find(ctx->id("BEL"));
+
+            if (loc_attr_cell != ci->attrs.end()) {
+                if (bel_attr_cell != ci->attrs.end()) {
+                    log_error("IO buffer %s has both a BEL attribute and LOC attribute.\n", ci->name.c_str(ctx));
+                }
+
+                log_info("found LOC attribute on IO buffer %s.\n", ci->name.c_str(ctx));
+                std::string pin = loc_attr_cell->second.as_string();
+
+                BelId pinBel = ctx->getPackagePinBel(pin);
+                if (pinBel == BelId()) {
+                    log_error("IO buffer '%s' constrained to pin '%s', which does not exist for package '%s'.\n",
+                              ci->name.c_str(ctx), pin.c_str(), ctx->args.package.c_str());
+                } else {
+                    log_info("pin '%s' constrained to Bel '%s'.\n", ci->name.c_str(ctx), ctx->nameOfBel(pinBel));
+                }
+                ci->attrs[ctx->id("BEL")] = ctx->getBelName(pinBel).str(ctx);
+            }
+        }
+    }
+
+    for (auto pcell : packed_cells) {
+        ctx->cells.erase(pcell);
+    }
+}
+
+// Main pack function
+bool Arch::pack()
+{
+    Context *ctx = getCtx();
+    try {
+        log_break();
+        pack_constants(ctx);
+        pack_io(ctx);
+        pack_lut_lutffs(ctx);
+        pack_remaining_ffs(ctx);
+        ctx->settings[ctx->id("pack")] = 1;
+        ctx->assignArchInfo();
+        log_info("Checksum: 0x%08x\n", ctx->checksum());
+        return true;
+    } catch (log_execution_error_exception) {
+        return false;
+    }
+}
+
+NEXTPNR_NAMESPACE_END