Merge pull request #118 from daveshah1/dcu

Adding ECP5 DCU support

1 files changed, 53 insertions, 1 deletions

diff --git a/ecp5/globals.cc b/ecp5/globals.cc
index 9b0928a4..66c62024 100644
--- a/ecp5/globals.cc
+++ b/ecp5/globals.cc
@@ -55,6 +55,9 @@ class Ecp5GlobalRouter
     {
         if (user.cell->type == id_TRELLIS_SLICE && (user.port == id_CLK || user.port == id_WCK))
             return true;
+        if (user.cell->type == id_DCUA && (user.port == id_CH0_FF_RXI_CLK || user.port == id_CH1_FF_RXI_CLK ||
+                                           user.port == id_CH0_FF_TXI_CLK || user.port == id_CH1_FF_TXI_CLK))
+            return true;
         return false;
     }
 
@@ -65,8 +68,11 @@ class Ecp5GlobalRouter
             NetInfo *ni = net.second.get();
             clockCount[ni->name] = 0;
             for (const auto &user : ni->users) {
-                if (is_clock_port(user))
+                if (is_clock_port(user)) {
                     clockCount[ni->name]++;
+                    if (user.cell->type == id_DCUA)
+                        clockCount[ni->name] += 100;
+                }
             }
             // log_info("clkcount %s: %d\n", ni->name.c_str(ctx),clockCount[ni->name]);
         }
@@ -290,6 +296,10 @@ class Ecp5GlobalRouter
             float tns;
             return get_net_metric(ctx, clki, MetricType::WIRELENGTH, tns);
         } else {
+            // Check for dedicated routing
+            if (has_short_route(ctx->getBelPinWire(drv_bel, drv.port), ctx->getBelPinWire(dcc->bel, id_CLKI))) {
+                return 0;
+            }
             // Driver is locked
             Loc dcc_loc = ctx->getBelLocation(dcc->bel);
             Loc drv_loc = ctx->getBelLocation(drv_bel);
@@ -297,6 +307,46 @@ class Ecp5GlobalRouter
         }
     }
 
+    // Return true if a short (<5) route exists between two wires
+    bool has_short_route(WireId src, WireId dst, int thresh = 5)
+    {
+        std::queue<WireId> visit;
+        std::unordered_map<WireId, PipId> backtrace;
+        visit.push(src);
+        WireId cursor;
+        while (true) {
+
+            if (visit.empty() || visit.size() > 1000) {
+                // log_info ("dist %s -> %s = inf\n", ctx->getWireName(src).c_str(ctx),
+                // ctx->getWireName(dst).c_str(ctx));
+                return false;
+            }
+            cursor = visit.front();
+            visit.pop();
+
+            if (cursor == dst)
+                break;
+            for (auto dh : ctx->getPipsDownhill(cursor)) {
+                WireId pipDst = ctx->getPipDstWire(dh);
+                if (backtrace.count(pipDst))
+                    continue;
+                backtrace[pipDst] = dh;
+                visit.push(pipDst);
+            }
+        }
+        int length = 0;
+        while (true) {
+            auto fnd = backtrace.find(cursor);
+            if (fnd == backtrace.end())
+                break;
+            cursor = ctx->getPipSrcWire(fnd->second);
+            length++;
+        }
+        // log_info ("dist %s -> %s = %d\n", ctx->getWireName(src).c_str(ctx), ctx->getWireName(dst).c_str(ctx),
+        // length);
+        return length < thresh;
+    }
+
     // Attempt to place a DCC
     void place_dcc(CellInfo *dcc)
     {
@@ -335,6 +385,8 @@ class Ecp5GlobalRouter
         for (auto user : net->users) {
             if (user.port == id_CLKFB) {
                 keep_users.push_back(user);
+            } else if (net->driver.cell->type == id_EXTREFB && user.cell->type == id_DCUA) {
+                keep_users.push_back(user);
             } else {
                 glbnet->users.push_back(user);
                 user.cell->ports.at(user.port).net = glbnet.get();