ecp5: Add IO buffer insertion

Signed-off-by: David Shah <dave@ds0.me>

4 files changed, 70 insertions, 15 deletions

diff --git a/ecp5/cells.cc b/ecp5/cells.cc
index a728104d..31839ee4 100644
--- a/ecp5/cells.cc
+++ b/ecp5/cells.cc
@@ -343,4 +343,46 @@ void dram_to_ram_slice(Context *ctx, CellInfo *ram, CellInfo *lc, CellInfo *ramw
     }
 }
 
+void nxio_to_tr(Context *ctx, CellInfo *nxio, CellInfo *trio, std::vector<std::unique_ptr<CellInfo>> &created_cells,
+                std::unordered_set<IdString> &todelete_cells)
+{
+    if (nxio->type == ctx->id("$nextpnr_ibuf")) {
+        trio->params[ctx->id("DIR")] = "INPUT";
+        replace_port(nxio, ctx->id("O"), trio, ctx->id("O"));
+    } else if (nxio->type == ctx->id("$nextpnr_obuf")) {
+        trio->params[ctx->id("DIR")] = "OUTPUT";
+        replace_port(nxio, ctx->id("I"), trio, ctx->id("I"));
+    } else if (nxio->type == ctx->id("$nextpnr_iobuf")) {
+        // N.B. tristate will be dealt with below
+        trio->params[ctx->id("DIR")] = "BIDIR";
+        replace_port(nxio, ctx->id("I"), trio, ctx->id("I"));
+        replace_port(nxio, ctx->id("O"), trio, ctx->id("O"));
+    } else {
+        NPNR_ASSERT(false);
+    }
+    NetInfo *donet = trio->ports.at(ctx->id("I")).net;
+    CellInfo *tbuf = net_driven_by(
+            ctx, donet, [](const Context *ctx, const CellInfo *cell) { return cell->type == ctx->id("$_TBUF_"); },
+            ctx->id("Y"));
+    if (tbuf) {
+        replace_port(tbuf, ctx->id("I"), trio, ctx->id("I"));
+        // Need to invert E to form T
+        std::unique_ptr<CellInfo> inv_lut = create_ecp5_cell(ctx, ctx->id("LUT4"), trio->name.str(ctx) + "$invert_T");
+        replace_port(tbuf, ctx->id("E"), inv_lut.get(), ctx->id("A"));
+        inv_lut->params[ctx->id("INIT")] = "21845";
+        connect_ports(ctx, inv_lut.get(), ctx->id("Z"), trio, ctx->id("T"));
+        created_cells.push_back(std::move(inv_lut));
+
+        if (donet->users.size() > 1) {
+            for (auto user : donet->users)
+                log_info("     remaining tristate user: %s.%s\n", user.cell->name.c_str(ctx), user.port.c_str(ctx));
+            log_error("unsupported tristate IO pattern for IO buffer '%s', "
+                      "instantiate SB_IO manually to ensure correct behaviour\n",
+                      nxio->name.c_str(ctx));
+        }
+        ctx->nets.erase(donet->name);
+        todelete_cells.insert(tbuf->name);
+    }
+}
+
 NEXTPNR_NAMESPACE_END
diff --git a/ecp5/cells.h b/ecp5/cells.h
index a5229fe0..9c2ff3cf 100644
--- a/ecp5/cells.h
+++ b/ecp5/cells.h
@@ -52,6 +52,10 @@ void ccu2c_to_slice(Context *ctx, CellInfo *ccu, CellInfo *lc);
 void dram_to_ramw(Context *ctx, CellInfo *ram, CellInfo *lc);
 void dram_to_ram_slice(Context *ctx, CellInfo *ram, CellInfo *lc, CellInfo *ramw, int index);
 
+// Convert a nextpnr IO buffer to a TRELLIS_IO
+void nxio_to_tr(Context *ctx, CellInfo *nxio, CellInfo *trio, std::vector<std::unique_ptr<CellInfo>> &created_cells,
+                std::unordered_set<IdString> &todelete_cells);
+
 NEXTPNR_NAMESPACE_END
 
 #endif
diff --git a/ecp5/lpf.cc b/ecp5/lpf.cc
index c8e61414..4bde660e 100644
--- a/ecp5/lpf.cc
+++ b/ecp5/lpf.cc
@@ -19,19 +19,22 @@
 
 #include <sstream>
 #include "log.h"
-#include "log.h"
 
 NEXTPNR_NAMESPACE_BEGIN
 
 bool Arch::applyLPF(std::string filename, std::istream &in)
 {
-    auto isempty = [] (const std::string &str) {return std::all_of(str.begin(), str.end(), [](char c){return isblank(c);});};
-    auto strip_quotes = [] (const std::string &str) {if (str.at(0) == '"') {
-        NPNR_ASSERT(str.back() == '"');
-        return str.substr(1, str.size() - 2);
-    } else {
-        return str;
-    }};
+    auto isempty = [](const std::string &str) {
+        return std::all_of(str.begin(), str.end(), [](char c) { return isblank(c); });
+    };
+    auto strip_quotes = [](const std::string &str) {
+        if (str.at(0) == '"') {
+            NPNR_ASSERT(str.back() == '"');
+            return str.substr(1, str.size() - 2);
+        } else {
+            return str;
+        }
+    };
 
     try {
         if (!in)
@@ -50,24 +53,24 @@ bool Arch::applyLPF(std::string filename, std::istream &in)
             while (scpos != std::string::npos) {
                 std::string command = linebuf.substr(0, scpos);
                 // Split command into words
-                std::stringstream ss(line);
+                std::stringstream ss(command);
                 std::vector<std::string> words;
                 std::string tmp;
                 while (ss >> tmp)
                     words.push_back(tmp);
                 if (words.size() >= 0) {
                     std::string verb = words.at(0);
-                    if(verb == "BLOCK" || verb == "SYSCONFIG" || verb == "FREQUENCY") {
+                    if (verb == "BLOCK" || verb == "SYSCONFIG" || verb == "FREQUENCY") {
                         log_warning("    ignoring unsupported LPF command '%s'\n", command.c_str());
                     } else if (verb == "LOCATE") {
                         NPNR_ASSERT(words.at(1) == "COMP");
                         std::string cell = strip_quotes(words.at(2));
-                        NPNR_ASSERT(words.at(1) == "SITE");
+                        NPNR_ASSERT(words.at(3) == "SITE");
                         auto fnd_cell = cells.find(id(cell));
                         if (fnd_cell == cells.end()) {
                             log_warning("unmatched LPF 'LOCATE COMP' '%s'\n", cell.c_str());
                         } else {
-                            fnd_cell->second->attrs[id("LOC")] = strip_quotes(words.at(3));
+                            fnd_cell->second->attrs[id("LOC")] = strip_quotes(words.at(4));
                         }
                     } else if (verb == "IOBUF") {
                         NPNR_ASSERT(words.at(1) == "PORT");
@@ -87,7 +90,7 @@ bool Arch::applyLPF(std::string filename, std::istream &in)
                     }
                 }
 
-                linebuf = linebuf.substr(scpos+1);
+                linebuf = linebuf.substr(scpos + 1);
                 scpos = linebuf.find(';');
             }
         }
diff --git a/ecp5/pack.cc b/ecp5/pack.cc
index 18debb74..cb111fc6 100644
--- a/ecp5/pack.cc
+++ b/ecp5/pack.cc
@@ -266,11 +266,17 @@ class Ecp5Packer
                         }
                     }
                 } else {
-                    log_error("TRELLIS_IO required on all top level IOs...\n");
+                    // Create a TRELLIS_IO buffer
+                    std::unique_ptr<CellInfo> tr_cell =
+                            create_ecp5_cell(ctx, ctx->id("TRELLIS_IO"), ci->name.str(ctx) + "$tr_io");
+                    nxio_to_tr(ctx, ci, tr_cell.get(), new_cells, packed_cells);
+                    new_cells.push_back(std::move(tr_cell));
+                    trio = new_cells.back().get();
                 }
 
                 packed_cells.insert(ci->name);
-                std::copy(ci->attrs.begin(), ci->attrs.end(), std::inserter(trio->attrs, trio->attrs.begin()));
+                for (const auto &attr : ci->attrs)
+                    trio->attrs[attr.first] = attr.second;
 
                 auto loc_attr = trio->attrs.find(ctx->id("LOC"));
                 if (loc_attr != trio->attrs.end()) {