Merge pull request #941 from yrabbit/gsr

gowin: Add the Global Set/Reset primitive

gowin/arch.cc

@@ -991,6 +991,14 @@ Arch::Arch(ArchArgs args) : args(args)
             int z = 0;
             bool dff = true;
             switch (static_cast<ConstIds>(bel->type_id)) {
+            case ID_GSR0:
+                snprintf(buf, 32, "R%dC%d_GSR0", row + 1, col + 1);
+                belname = id(buf);
+                addBel(belname, id_GSR, Loc(col, row, 0), false);
+                portname = IdString(pairLookup(bel->ports.get(), bel->num_ports, ID_GSRI)->src_id);
+                snprintf(buf, 32, "R%dC%d_%s", row + 1, col + 1, portname.c_str(this));
+                addBelInput(belname, id_GSRI, id(buf));
+                break;
             // fall through the ++
             case ID_LUT7:
                 z++;

gowin/cells.cc

@@ -63,6 +63,8 @@ std::unique_ptr<CellInfo> create_generic_cell(Context *ctx, IdString type, std::
         new_cell->addInput(id_I);
         new_cell->addInput(id_OEN);
         new_cell->addOutput(id_O);
+    } else if (type == id_GSR) {
+        new_cell->addInput(id_GSRI);
     } else {
         log_error("unable to create generic cell of type %s\n", type.c_str(ctx));
     }

gowin/constids.inc

@@ -739,6 +739,11 @@ X(IOBUF)
 X(TBUF)
 X(TLVDS_OBUF)
 
+// global set/reset
+X(GSR)
+X(GSR0)
+X(GSRI)
+
 // primitive attributes
 X(INIT)
 X(FF_USED)

gowin/pack.cc

@@ -660,6 +660,41 @@ static void pack_constants(Context *ctx)
     }
 }
 
+// Pack global set-reset
+static void pack_gsr(Context *ctx)
+{
+    log_info("Packing GSR..\n");
+
+    bool user_gsr = false;
+    for (auto &cell : ctx->cells) {
+        CellInfo *ci = cell.second.get();
+        if (ctx->verbose)
+            log_info("cell '%s' is of type '%s'\n", ctx->nameOf(ci), ci->type.c_str(ctx));
+        if (ci->type == id_GSR) {
+            user_gsr = true;
+            break;
+        }
+    }
+    if (!user_gsr) {
+        // XXX
+        bool have_gsr_bel = false;
+        for (auto bi : ctx->bels) {
+            if (bi.second.type == id_GSR) {
+                have_gsr_bel = true;
+                break;
+            }
+        }
+        if (have_gsr_bel) {
+            // make default GSR
+            std::unique_ptr<CellInfo> gsr_cell = create_generic_cell(ctx, id_GSR, "GSR");
+            gsr_cell->connectPort(id_GSRI, ctx->nets[ctx->id("$PACKER_VCC_NET")].get());
+            ctx->cells[gsr_cell->name] = std::move(gsr_cell);
+        } else {
+            log_info("No GSR in the chip base\n");
+        }
+    }
+}
+
 static bool is_nextpnr_iob(const Context *ctx, CellInfo *cell)
 {
     return cell->type == ctx->id("$nextpnr_ibuf") || cell->type == ctx->id("$nextpnr_obuf") ||
@@ -857,6 +892,7 @@ bool Arch::pack()
     try {
         log_break();
         pack_constants(ctx);
+        pack_gsr(ctx);
         pack_io(ctx);
         pack_diff_io(ctx);
         pack_wideluts(ctx);