feat: Chip ROM auto generation with OpenLane 2

So we can generate the ROM while building the shuttle's GDS

configure.py

@@ -244,7 +244,7 @@ if __name__ == '__main__':
         shuttle.configure_mux()
         if args.test:
             shuttle.write_gl_config()
-        #rom.write_rom()
+        rom.write_rom()
         if not args.test:
             docs.build_index()
 

rom.py

@@ -1,4 +1,8 @@
 import git
+import os
+from urllib.parse import urlparse
+
+MAX_ROM_TEXT_SIZE = 92
 
 segment_font = {
     " ": 0b00000000,
@@ -30,7 +34,8 @@ class ROMFile:
         self.config = config
 
     def get_git_remote(self):
-        return list(git.Repo(".").remotes[0].urls)[0]
+        repo_url = list(git.Repo(".").remotes[0].urls)[0]
+        return urlparse(repo_url).path[1:]
 
     def get_git_commit_hash(self):
         return git.Repo(".").commit().hexsha
@@ -39,18 +44,25 @@ class ROMFile:
         rom = bytearray(256)
         short_sha = self.get_git_commit_hash()[:8]
 
-        rom_text = f"shuttle={self.config['name']}\n"
+        rom_text = f"shuttle={self.config['id']}\n"
         rom_text += f"repo={self.get_git_remote()}\n"
         rom_text += f"commit={short_sha}\n"
 
-        assert len(rom_text) < 96, "ROM text too long"
+        print(f"\nROM text: {len(rom_text)} bytes (max={MAX_ROM_TEXT_SIZE})\n")
+        print("  " + "\n  ".join(rom_text.split("\n")))
 
-        rom[0:4] = map(segment_char, "tt04")
+        assert len(rom_text) < MAX_ROM_TEXT_SIZE, "ROM text too long"
+
+        rom[0:4] = map(segment_char, self.config['id'])
         rom[8:16] = map(segment_char, short_sha.upper())
         rom[32 : 32 + len(rom_text)] = rom_text.encode("ascii")
 
-        # build complete list of filenames for sim
+        with open(os.path.join(os.path.dirname(__file__), "rom/rom.vmem"), "w") as fh:
-        with open("verilog/includes/rom_tile.vmem", "w") as fh:
+            for line in rom_text.split("\n"):
+                if len(line) == 0:
+                    continue
+                fh.write(f"// {line}\n")
+            fh.write("\n")
             for line in range(0, len(rom), 16):
                 for byte in range(0, 16):
                     fh.write("{:02x} ".format(rom[line + byte]))

rom/.gitignore

@@ -0,0 +1,2 @@
+runs
+rom.vmem

rom/config.json

@@ -0,0 +1,31 @@
+{
+  "DESIGN_NAME": "tt_um_chip_rom",
+  "VERILOG_FILES": "dir::tt_um_chip_rom.v",
+  
+  "FP_SIZING": "absolute",
+  "DIE_AREA": "0 0 168.36 111.52",
+  "FP_DEF_TEMPLATE": "ref::$DESIGN_DIR/../def/tt_block_1x1.def",
+
+  "FP_IO_HLENGTH": 2,
+  "FP_IO_VLENGTH": 2,
+
+  "//": "use alternative efabless decap cells to solve LI density issue",
+  "DECAP_CELL": "sky130_fd_sc_hd__decap_3 sky130_fd_sc_hd__decap_4 sky130_fd_sc_hd__decap_6 sky130_fd_sc_hd__decap_8 sky130_ef_sc_hd__decap_12",
+
+  "//": "period is in ns, so 20ns == 50mHz",
+  "CLOCK_PERIOD": 20,
+  "CLOCK_PORT": "clk",
+
+  "//": "don't use power rings or met5",
+  "DESIGN_IS_CORE": false,
+  "RT_MAX_LAYER": "met4",
+
+  "//": "save some time",
+  "RUN_KLAYOUT_XOR": false,
+
+  "//": "reduce wasted space",
+  "TOP_MARGIN_MULT": 1,
+  "BOTTOM_MARGIN_MULT": 1,
+  "LEFT_MARGIN_MULT": 6,
+  "RIGHT_MARGIN_MULT": 6
+}

rom/tt_um_chip_rom.v

@@ -0,0 +1,32 @@
+/*
+ * tt_um_chip_rom.v
+ *
+ * ROM module for Tiny Tapeout chips
+ *
+ * Author: Uri Shaked
+ */
+
+`default_nettype none
+
+module tt_um_chip_rom (
+	input  wire [7:0] ui_in,	// Dedicated inputs
+	output wire [7:0] uo_out,	// Dedicated outputs
+	input  wire [7:0] uio_in,	// IOs: Input path
+	output wire [7:0] uio_out,// IOs: Output path
+	output wire [7:0] uio_oe,	// IOs: Enable path (active high: 0=input, 1=output)
+	input  wire       ena,
+	input  wire       clk,
+	input  wire       rst_n
+);
+
+	reg [7:0] rom_data [0:255];
+
+  initial begin
+		$readmemh("rom.vmem", rom_data);
+	end
+	
+	assign uo_out  = rom_data[ui_in];
+	assign uio_out = 8'h00;
+	assign uio_oe  = 8'h00;
+
+endmodule // tt_um_chip_rom

shuttle.py

@@ -100,6 +100,8 @@ class ShuttleConfig():
 
     def find_last_run(self, macro: str):
         runs = f"tt-multiplexer/ol2/{macro}/runs/"
+        if macro == "tt_um_chip_rom":
+            runs = "tt/rom/runs/"
         runlist = sorted(
             [r for r in os.listdir(runs) if r.startswith("RUN_") and os.path.isdir(os.path.join(runs, r))]
         )
@@ -115,7 +117,7 @@ class ShuttleConfig():
         copy_print_glob("projects/*/*.gds", "tt-multiplexer/ol2/tt_top/gds")
         copy_print_glob("projects/*/*.lef", "tt-multiplexer/ol2/tt_top/lef")
         copy_print_glob("projects/*/*.v", "tt-multiplexer/ol2/tt_top/verilog")
-        macros = ["tt_ctrl", "tt_mux"]
+        macros = ["tt_um_chip_rom", "tt_ctrl", "tt_mux"]
         for macro in macros:
             lastrun = self.find_last_run(macro)
             copy_print(f"{lastrun}/final/gds/{macro}.gds", f"tt-multiplexer/ol2/tt_top/gds/{macro}.gds")