Working on the timing annotator

Signed-off-by: David Shah <davey1576@gmail.com>

common/timing.cc

@@ -62,12 +62,13 @@ static delay_t follow_user_port(Context *ctx, PortRef &user, int path_length,
     if (value < user.budget) {
         user.budget = value;
     }
+    return value;
 }
 
 static delay_t follow_net(Context *ctx, NetInfo *net, int path_length,
                           delay_t slack)
 {
-    delay_t net_budget = slack / path_length;
+    delay_t net_budget = slack / (path_length + 1);
     for (auto &usr : net->users) {
         net_budget = std::min(
                 net_budget, follow_user_port(ctx, usr, path_length + 1, slack));
@@ -77,6 +78,7 @@ static delay_t follow_net(Context *ctx, NetInfo *net, int path_length,
 
 void assign_budget(Context *ctx, float default_clock)
 {
+    log_info("Annotating ports with timing budgets\n");
     for (auto cell : ctx->cells) {
         for (auto port : cell.second->ports) {
             if (port.second.type == PORT_OUT) {

ice40/arch.cc

@@ -21,7 +21,7 @@
 #include <cmath>
 #include "log.h"
 #include "nextpnr.h"
-
+#include "util.h"
 NEXTPNR_NAMESPACE_BEGIN
 
 // -----------------------------------------------------------------------
@@ -414,26 +414,39 @@ std::vector<GraphicElement> Arch::getPipGraphics(PipId pip) const
     std::vector<GraphicElement> ret;
     // FIXME
     return ret;
-}
+};
 
 // -----------------------------------------------------------------------
 
 bool Arch::getCellDelay(const CellInfo *cell, IdString fromPort,
                         IdString toPort, delay_t &delay) const
 {
-    // TODO
+    if (cell->type == id("ICESTORM_LC")) {
+        if (fromPort == id("I0") || fromPort == id("I1") ||
+            fromPort == id("I2") || fromPort == id("I3")) {
+            if (toPort == id("O") || toPort == id("LO")) {
+                delay = 450;
+                return true;
+            }
+        }
+    }
     return false;
 }
 
 IdString Arch::getPortClock(const CellInfo *cell, IdString port) const
 {
-    // TODO
+    if (cell->type == id("ICESTORM_LC") &&
+        bool_or_default(cell->params, id("DFF_ENABLE"))) {
+        if (port != id("LO") && port != id("CIN") && port != id("COUT"))
+            return id("CLK");
+    }
     return IdString();
 }
 
 bool Arch::isClockPort(const CellInfo *cell, IdString port) const
 {
-    // TODO
+    if (cell->type == id("ICESTORM_LC") && port == id("CLK"))
+        return true;
     return false;
 }
 

ice40/main.cc

@@ -36,6 +36,7 @@
 #include "pybindings.h"
 #include "route.h"
 #include "version.h"
+#include "timing.h"
 
 void svg_dump_el(const GraphicElement &el)
 {
@@ -232,7 +233,7 @@ int main(int argc, char *argv[])
 
         if (!pack_design(&ctx) && !ctx.force)
             log_error("Packing design failed.\n");
-
+        assign_budget(&ctx);
         print_utilisation(&ctx);
 
         if (!vm.count("pack-only")) {