From 4ba4c6b8971d0c3edf332fb99c27d5847759ec96 Mon Sep 17 00:00:00 2001
From: Keith Rothman <537074+litghost@users.noreply.github.com>
Date: Tue, 15 Jan 2019 12:17:40 -0800
Subject: [PATCH 1/3] Add retries to bidirection PIP fuzzer.

Signed-off-by: Keith Rothman <537074+litghost@users.noreply.github.com>
---
 fuzzers/057-pip-bi/generate.tcl | 50 +++++++++++++++++++++++++--------
 1 file changed, 39 insertions(+), 11 deletions(-)

diff --git a/fuzzers/057-pip-bi/generate.tcl b/fuzzers/057-pip-bi/generate.tcl
index a6b10245..10dbdd0e 100644
--- a/fuzzers/057-pip-bi/generate.tcl
+++ b/fuzzers/057-pip-bi/generate.tcl
@@ -41,22 +41,50 @@ for {set idx 0} {$idx < [llength $todo_lines]} {incr idx} {
     set dst_wire [lindex $line 1]
     set src_wire [lindex $line 2]
 
-    if {$tile_type == "INT_L"} {set tile [lindex $int_l_tiles $idx]; set other_tile [lindex $int_r_tiles $idx]}
-    if {$tile_type == "INT_R"} {set tile [lindex $int_r_tiles $idx]; set other_tile [lindex $int_l_tiles $idx]}
+    set tries 0
+    while {1} {
+        set tile_idx [expr $tries + [expr $idx * 3]]
+        incr tries
 
-    puts "PIP Tile: $tile"
+        if {$tile_type == "INT_L"} {set tile [lindex $int_l_tiles $tile_idx]; set other_tile [lindex $int_r_tiles $idx]}
+        if {$tile_type == "INT_R"} {set tile [lindex $int_r_tiles $tile_idx]; set other_tile [lindex $int_l_tiles $idx]}
 
-    set driver_site [get_sites -of_objects [get_site_pins -of_objects [get_nodes -downhill \
-            -of_objects [get_nodes -of_objects [get_wires $other_tile/CLK*0]]]]]
+        puts "PIP Tile: $tile"
 
-    puts "LUT Tile (Site): $other_tile ($driver_site)"
+        set driver_site [get_sites -of_objects [get_site_pins -of_objects [get_nodes -downhill \
+                -of_objects [get_nodes -of_objects [get_wires $other_tile/CLK*0]]]]]
 
-    set mylut [create_cell -reference LUT1 mylut_$idx]
-    set_property -dict "LOC $driver_site BEL A6LUT" $mylut
+        puts "LUT Tile (Site): $other_tile ($driver_site)"
 
-    set mynet [create_net mynet_$idx]
-    connect_net -net $mynet -objects "$mylut/I0 $mylut/O"
-    route_via $mynet "$tile/$src_wire $tile/$dst_wire"
+        set mylut [create_cell -reference LUT1 mylut_$idx]
+        set_property -dict "LOC $driver_site BEL A6LUT" $mylut
+
+        set mynet [create_net mynet_$idx]
+        connect_net -net $mynet -objects "$mylut/I0 $mylut/O"
+        set rc [route_via $mynet "$tile/$src_wire $tile/$dst_wire" 0]
+        if {$rc != 0} {
+            puts "ROUTING DONE!"
+            break
+        }
+
+        # fallback
+        puts "WARNING: failed to route net"
+        write_checkpoint -force route_todo_$idx.$tries.fail.dcp
+
+        puts "Rolling back route"
+        set_property is_route_fixed 0 $mynet
+        set_property is_bel_fixed 0 $mylut
+        set_property is_loc_fixed 1 $mylut
+        set_property is_bel_fixed 0 $myff
+        set_property is_loc_fixed 1 $myff
+        route_design -unroute -nets $mynet
+
+        # sometimes it gets stuck in specific src -> dst locations
+        if {$tries >= 3} {
+            puts "WARNING: failed to route net after $tries tries"
+            error
+        }
+    }
 
     if {[get_pips -filter "NAME == \"${tile}/${tile_type}.${src_wire}<<->>${dst_wire}\" || NAME == \"${tile}/${tile_type}.${dst_wire}<<->>${src_wire}\""  -of_objects [get_nets $mynet]] != ""} {
         puts $fp "A $tile/$dst_wire $tile/$src_wire"

From dc060064c39b762b2303208f2ead3485ef30788d Mon Sep 17 00:00:00 2001
From: Keith Rothman <537074+litghost@users.noreply.github.com>
Date: Tue, 15 Jan 2019 12:30:52 -0800
Subject: [PATCH 2/3] Fix copy/paste error, no such var as myff.

Signed-off-by: Keith Rothman <537074+litghost@users.noreply.github.com>
---
 fuzzers/057-pip-bi/generate.tcl | 2 --
 1 file changed, 2 deletions(-)

diff --git a/fuzzers/057-pip-bi/generate.tcl b/fuzzers/057-pip-bi/generate.tcl
index 10dbdd0e..84dd588f 100644
--- a/fuzzers/057-pip-bi/generate.tcl
+++ b/fuzzers/057-pip-bi/generate.tcl
@@ -75,8 +75,6 @@ for {set idx 0} {$idx < [llength $todo_lines]} {incr idx} {
         set_property is_route_fixed 0 $mynet
         set_property is_bel_fixed 0 $mylut
         set_property is_loc_fixed 1 $mylut
-        set_property is_bel_fixed 0 $myff
-        set_property is_loc_fixed 1 $myff
         route_design -unroute -nets $mynet
 
         # sometimes it gets stuck in specific src -> dst locations

From 63b397199ced34102737bc85415dee555a53dd28 Mon Sep 17 00:00:00 2001
From: Keith Rothman <537074+litghost@users.noreply.github.com>
Date: Tue, 15 Jan 2019 12:38:11 -0800
Subject: [PATCH 3/3] Move 1-time part of loop out of loop.

Signed-off-by: Keith Rothman <537074+litghost@users.noreply.github.com>
---
 fuzzers/057-pip-bi/generate.tcl | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/fuzzers/057-pip-bi/generate.tcl b/fuzzers/057-pip-bi/generate.tcl
index 84dd588f..f09b5d28 100644
--- a/fuzzers/057-pip-bi/generate.tcl
+++ b/fuzzers/057-pip-bi/generate.tcl
@@ -41,6 +41,11 @@ for {set idx 0} {$idx < [llength $todo_lines]} {incr idx} {
     set dst_wire [lindex $line 1]
     set src_wire [lindex $line 2]
 
+    set mylut [create_cell -reference LUT1 mylut_$idx]
+
+    set mynet [create_net mynet_$idx]
+    connect_net -net $mynet -objects "$mylut/I0 $mylut/O"
+
     set tries 0
     while {1} {
         set tile_idx [expr $tries + [expr $idx * 3]]
@@ -56,11 +61,8 @@ for {set idx 0} {$idx < [llength $todo_lines]} {incr idx} {
 
         puts "LUT Tile (Site): $other_tile ($driver_site)"
 
-        set mylut [create_cell -reference LUT1 mylut_$idx]
         set_property -dict "LOC $driver_site BEL A6LUT" $mylut
 
-        set mynet [create_net mynet_$idx]
-        connect_net -net $mynet -objects "$mylut/I0 $mylut/O"
         set rc [route_via $mynet "$tile/$src_wire $tile/$dst_wire" 0]
         if {$rc != 0} {
             puts "ROUTING DONE!"