From 409992961c86e1933dd0f5a9d5fdec624fa61afe Mon Sep 17 00:00:00 2001
From: Jacob Lifshay <programmerjake@gmail.com>
Date: Tue, 21 Oct 2025 19:53:15 -0700
Subject: [PATCH] switch to using verilog for reset synchronizer so we can use
 attributes on FDPE instances

---
 crates/fayalite/src/vendor/xilinx/arty_a7.rs | 82 ++++++++++++--------
 1 file changed, 50 insertions(+), 32 deletions(-)

diff --git a/crates/fayalite/src/vendor/xilinx/arty_a7.rs b/crates/fayalite/src/vendor/xilinx/arty_a7.rs
index 0559199..f0a3f96 100644
--- a/crates/fayalite/src/vendor/xilinx/arty_a7.rs
+++ b/crates/fayalite/src/vendor/xilinx/arty_a7.rs
@@ -1,14 +1,10 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
 // See Notices.txt for copyright information
 
-use std::sync::OnceLock;
-
-use ordered_float::NotNan;
-
 use crate::{
     annotations::Annotation,
     intern::{Intern, Interned},
-    module::{instance_with_loc, reg_builder_with_loc, wire_with_loc},
+    module::instance_with_loc,
     platform::{
         DynPlatform, Peripheral, PeripheralRef, Peripherals, PeripheralsBuilderFactory,
         PeripheralsBuilderFinished, Platform, PlatformAspectSet,
@@ -20,6 +16,8 @@ use crate::{
         primitives::{self, BUFGCE, STARTUPE2_default_inputs},
     },
 };
+use ordered_float::NotNan;
+use std::sync::OnceLock;
 
 macro_rules! arty_a7_platform {
     (
@@ -120,6 +118,45 @@ impl ArtyA7Platform {
     }
 }
 
+#[hdl_module(extern)]
+fn reset_sync() {
+    #[hdl]
+    let clk: Clock = m.input();
+    #[hdl]
+    let inp: Bool = m.input();
+    #[hdl]
+    let out: SyncReset = m.output();
+    m.annotate_module(BlackBoxInlineAnnotation {
+        path: "fayalite_arty_a7_reset_sync.v".intern(),
+        text: r#"module __fayalite_arty_a7_reset_sync(input clk, input inp, output out);
+    wire reset_0_out;
+    (* ASYNC_REG = "TRUE" *)
+    FDPE #(
+        .INIT(1'b1)
+    ) reset_0 (
+        .Q(reset_0_out),
+        .C(clk),
+        .CE(1'b1),
+        .PRE(inp),
+        .D(1'b0)
+    );
+    (* ASYNC_REG = "TRUE" *)
+    FDPE #(
+        .INIT(1'b1)
+    ) reset_1 (
+        .Q(out),
+        .C(clk),
+        .CE(1'b1),
+        .PRE(inp),
+        .D(reset_0_out)
+    );
+endmodule
+"#
+        .intern(),
+    });
+    m.verilog_name("__fayalite_arty_a7_reset_sync");
+}
+
 impl Platform for ArtyA7Platform {
     type Peripherals = ArtyA7Peripherals;
 
@@ -236,36 +273,17 @@ impl Platform for ArtyA7Platform {
         let clk100_sync = instance_with_loc("clk100_sync", BUFGCE(), SourceLocation::builtin());
         connect(clk100_sync.CE, startup.EOS);
         connect(clk100_sync.I, clk100_buf);
+        annotate(clk100_sync.O, clock_annotation);
         if let Some(clk100) = clk100.into_used() {
             connect(clk100.instance_io_field().clk, clk100_sync.O);
         }
-        let rst_buf = make_buffered_input("rst", "C2", "LVCMOS33", &[], true);
-        let rst_sync_cd = wire_with_loc(
-            "rst_sync_cd",
-            SourceLocation::builtin(),
-            ClockDomain[AsyncReset],
-        );
-        annotate(clk100_sync.O, clock_annotation);
-        connect(rst_sync_cd.clk, clk100_sync.O);
-        connect(rst_sync_cd.rst, rst_buf.to_async_reset());
-        let [rst_sync_0, rst_sync_1] = std::array::from_fn(|index| {
-            let rst_sync =
-                reg_builder_with_loc(&format!("rst_sync_{index}"), SourceLocation::builtin())
-                    .clock_domain(rst_sync_cd)
-                    .reset(true)
-                    .build();
-            annotate(
-                rst_sync,
-                SVAttributeAnnotation {
-                    text: "ASYNC_REG = \"TRUE\"".intern(),
-                },
-            );
-            annotate(rst_sync, DontTouchAnnotation);
-            rst_sync
-        });
-        connect(rst_sync_0, false);
-        connect(rst_sync_1, rst_sync_0);
-        let rst_value = rst_sync_1.to_sync_reset();
+        let rst_value = {
+            let rst_buf = make_buffered_input("rst", "C2", "LVCMOS33", &[], true);
+            let rst_sync = instance_with_loc("rst_sync", reset_sync(), SourceLocation::builtin());
+            connect(rst_sync.clk, clk100_sync.O);
+            connect(rst_sync.inp, rst_buf);
+            rst_sync.out
+        };
         if let Some(rst) = rst.into_used() {
             connect(rst.instance_io_field(), rst_value.to_reset());
         }