ecp5: Add support for mapping PRLD FFs

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

2 files changed, 28 insertions, 4 deletions

diff --git a/techlibs/ecp5/cells_map.v b/techlibs/ecp5/cells_map.v
index 71ae9237b..10e89a3e0 100644
--- a/techlibs/ecp5/cells_map.v
+++ b/techlibs/ecp5/cells_map.v
@@ -47,6 +47,21 @@ module  \$__DFFSE_NP1 (input D, C, E, R, output Q); TRELLIS_FF #(.GSR("AUTO"), .
 module  \$__DFFSE_PP0 (input D, C, E, R, output Q); TRELLIS_FF #(.GSR("AUTO"), .CEMUX("CE"), .CLKMUX("CLK"), .LSRMUX("LSR"), .REGSET("RESET"), .SRMODE("LSR_OVER_CE"))  _TECHMAP_REPLACE_ (.CLK(C), .CE(E), .LSR(R), .DI(D), .Q(Q)); endmodule
 module  \$__DFFSE_PP1 (input D, C, E, R, output Q); TRELLIS_FF #(.GSR("AUTO"), .CEMUX("CE"), .CLKMUX("CLK"), .LSRMUX("LSR"), .REGSET("SET"), .SRMODE("LSR_OVER_CE"))  _TECHMAP_REPLACE_ (.CLK(C), .CE(E), .LSR(R), .DI(D), .Q(Q)); endmodule
 
+`ifdef ASYNC_PRLD
+module  \$_DLATCH_N_ (input E, input D, output Q); TRELLIS_FF #(.GSR("DISABLED"), .CEMUX("1"), .LSRMODE("PRLD"), .LSRMUX("LSR"), .REGSET("RESET"), .SRMODE("ASYNC"))  _TECHMAP_REPLACE_ (.LSR(!E), .DI(1'b0), .M(D), .Q(Q)); endmodule
+module  \$_DLATCH_P_ (input E, input D, output Q); TRELLIS_FF #(.GSR("DISABLED"), .CEMUX("1"), .LSRMODE("PRLD"), .LSRMUX("LSR"), .REGSET("RESET"), .SRMODE("ASYNC"))  _TECHMAP_REPLACE_ (.LSR(E), .DI(1'b0), .M(D), .Q(Q)); endmodule
+
+module \$_DFFSR_NNN_ (input C, S, R, D, output Q); TRELLIS_FF #(.GSR("DISABLED"), .CEMUX("1"), .CLKMUX("INV"), .LSRMODE("PRLD"), .LSRMUX("LSR"), .REGSET("RESET"), .SRMODE("ASYNC"))  _TECHMAP_REPLACE_ (.CLK(C), .LSR(!S || !R), .DI(D), .M(R), .Q(Q)); endmodule
+module \$_DFFSR_NNP_ (input C, S, R, D, output Q); TRELLIS_FF #(.GSR("DISABLED"), .CEMUX("1"), .CLKMUX("INV"), .LSRMODE("PRLD"), .LSRMUX("LSR"), .REGSET("RESET"), .SRMODE("ASYNC"))  _TECHMAP_REPLACE_ (.CLK(C), .LSR(!S || R), .DI(D), .M(!R), .Q(Q)); endmodule
+module \$_DFFSR_NPN_ (input C, S, R, D, output Q); TRELLIS_FF #(.GSR("DISABLED"), .CEMUX("1"), .CLKMUX("INV"), .LSRMODE("PRLD"), .LSRMUX("LSR"), .REGSET("RESET"), .SRMODE("ASYNC"))  _TECHMAP_REPLACE_ (.CLK(C), .LSR(S || !R), .DI(D), .M(R), .Q(Q)); endmodule
+module \$_DFFSR_NPP_ (input C, S, R, D, output Q); TRELLIS_FF #(.GSR("DISABLED"), .CEMUX("1"), .CLKMUX("INV"), .LSRMODE("PRLD"), .LSRMUX("LSR"), .REGSET("RESET"), .SRMODE("ASYNC"))  _TECHMAP_REPLACE_ (.CLK(C), .LSR(S || R), .DI(D), .M(!R), .Q(Q)); endmodule
+
+module \$_DFFSR_PNN_ (input C, S, R, D, output Q); TRELLIS_FF #(.GSR("DISABLED"), .CEMUX("1"), .CLKMUX("CLK"), .LSRMODE("PRLD"), .LSRMUX("LSR"), .REGSET("RESET"), .SRMODE("ASYNC"))  _TECHMAP_REPLACE_ (.CLK(C), .LSR(!S || !R), .DI(D), .M(R), .Q(Q)); endmodule
+module \$_DFFSR_PNP_ (input C, S, R, D, output Q); TRELLIS_FF #(.GSR("DISABLED"), .CEMUX("1"), .CLKMUX("CLK"), .LSRMODE("PRLD"), .LSRMUX("LSR"), .REGSET("RESET"), .SRMODE("ASYNC"))  _TECHMAP_REPLACE_ (.CLK(C), .LSR(!S || R), .DI(D), .M(!R), .Q(Q)); endmodule
+module \$_DFFSR_PPN_ (input C, S, R, D, output Q); TRELLIS_FF #(.GSR("DISABLED"), .CEMUX("1"), .CLKMUX("CLK"), .LSRMODE("PRLD"), .LSRMUX("LSR"), .REGSET("RESET"), .SRMODE("ASYNC"))  _TECHMAP_REPLACE_ (.CLK(C), .LSR(S || !R), .DI(D), .M(R), .Q(Q)); endmodule
+module \$_DFFSR_PPP_ (input C, S, R, D, output Q); TRELLIS_FF #(.GSR("DISABLED"), .CEMUX("1"), .CLKMUX("CLK"), .LSRMODE("PRLD"), .LSRMUX("LSR"), .REGSET("RESET"), .SRMODE("ASYNC"))  _TECHMAP_REPLACE_ (.CLK(C), .LSR(S || R), .DI(D), .M(!R), .Q(Q)); endmodule
+`endif
+
 `include "cells_ff.vh"
 `include "cells_io.vh"
 
diff --git a/techlibs/ecp5/synth_ecp5.cc b/techlibs/ecp5/synth_ecp5.cc
index 4cbb56ea1..b71bb2395 100644
--- a/techlibs/ecp5/synth_ecp5.cc
+++ b/techlibs/ecp5/synth_ecp5.cc
@@ -79,6 +79,9 @@ struct SynthEcp5Pass : public ScriptPass
 		log("    -nowidelut\n");
 		log("        do not use PFU muxes to implement LUTs larger than LUT4s\n");
 		log("\n");
+		log("    -asyncprld\n");
+		log("        use async PRLD mode to implement DLATCH and DFFSR (EXPERIMENTAL)\n");
+		log("\n");
 		log("    -abc2\n");
 		log("        run two passes of 'abc' for slightly improved logic density\n");
 		log("\n");
@@ -99,7 +102,7 @@ struct SynthEcp5Pass : public ScriptPass
 	}
 
 	string top_opt, blif_file, edif_file, json_file;
-	bool noccu2, nodffe, nobram, nolutram, nowidelut, flatten, retime, abc2, abc9, nodsp, vpr;
+	bool noccu2, nodffe, nobram, nolutram, nowidelut, asyncprld, flatten, retime, abc2, abc9, nodsp, vpr;
 
 	void clear_flags() YS_OVERRIDE
 	{
@@ -112,6 +115,7 @@ struct SynthEcp5Pass : public ScriptPass
 		nobram = false;
 		nolutram = false;
 		nowidelut = false;
+		asyncprld = false;
 		flatten = true;
 		retime = false;
 		abc2 = false;
@@ -176,6 +180,10 @@ struct SynthEcp5Pass : public ScriptPass
 				nobram = true;
 				continue;
 			}
+			if (args[argidx] == "-asyncprld") {
+				asyncprld = true;
+				continue;
+			}
 			if (args[argidx] == "-nolutram" || /*deprecated alias*/ args[argidx] == "-nodram") {
 				nolutram = true;
 				continue;
@@ -292,7 +300,7 @@ struct SynthEcp5Pass : public ScriptPass
 			run("opt_clean");
 			if (!nodffe)
 				run("dff2dffe -direct-match $_DFF_* -direct-match $__DFFS_*");
-			run("techmap -D NO_LUT -map +/ecp5/cells_map.v");
+			run(stringf("techmap -D NO_LUT %s -map +/ecp5/cells_map.v", help_mode ? "[-D ASYNC_PRLD]" : (asyncprld ? "-D ASYNC_PRLD" : "")));
 			run("opt_expr -undriven -mux_undef");
 			run("simplemap");
 			run("ecp5_ffinit");
@@ -306,10 +314,11 @@ struct SynthEcp5Pass : public ScriptPass
 			if (abc2 || help_mode) {
 				run("abc", "      (only if -abc2)");
 			}
-			std::string techmap_args = "-map +/ecp5/latches_map.v";
+			std::string techmap_args = asyncprld ? "" : "-map +/ecp5/latches_map.v";
 			if (abc9)
 				techmap_args += " -map +/ecp5/abc9_map.v -max_iter 1";
-			run("techmap " + techmap_args);
+			if (!asyncprld || abc9)
+				run("techmap " + techmap_args);
 
 			if (abc9) {
 				run("read_verilog -icells -lib +/ecp5/abc9_model.v");