From feb7a0d4c2c050ca25fb85dfe627c5c8232b42ad Mon Sep 17 00:00:00 2001
From: rdon <you@example.com>
Date: Mon, 29 Jun 2026 22:18:31 +0900
Subject: [PATCH] runtime/rp2: handle RP2350 shared FIFO IRQ for GC

---
 src/runtime/runtime_rp2.go    | 19 ++-----------------
 src/runtime/runtime_rp2040.go | 23 +++++++++++++++++++++++
 src/runtime/runtime_rp2350.go | 20 ++++++++++++++++++++
 3 files changed, 45 insertions(+), 17 deletions(-)

diff --git a/src/runtime/runtime_rp2.go b/src/runtime/runtime_rp2.go
index 1cd23d6dcb..f6d31f9806 100644
--- a/src/runtime/runtime_rp2.go
+++ b/src/runtime/runtime_rp2.go
@@ -8,7 +8,6 @@ import (
 	"internal/task"
 	"machine"
 	_ "machine/usb/cdc"
-	"runtime/interrupt"
 	"runtime/volatile"
 	"unsafe"
 )
@@ -140,14 +139,7 @@ func startSecondaryCores() {
 	// Enable the FIFO interrupt for the GC stop the world phase.
 	// We can only do this after we don't need the FIFO anymore for starting the
 	// second core.
-	intr := interrupt.New(sioIrqFifoProc0, func(intr interrupt.Interrupt) {
-		switch rp.SIO.FIFO_RD.Get() {
-		case 1:
-			gcInterruptHandler(0)
-		}
-	})
-	intr.Enable()
-	intr.SetPriority(0xff)
+	enableSIOFifoInterruptCore0()
 }
 
 var core1StartSequence = [...]uint32{
@@ -174,14 +166,7 @@ func runCore1() {
 	// the GC.
 	// Use the lowest possible priority (highest priority value), so that other
 	// interrupts can still happen while the GC is running.
-	intr := interrupt.New(sioIrqFifoProc1, func(intr interrupt.Interrupt) {
-		switch rp.SIO.FIFO_RD.Get() {
-		case 1:
-			gcInterruptHandler(1)
-		}
-	})
-	intr.Enable()
-	intr.SetPriority(0xff)
+	enableSIOFifoInterruptCore1()
 
 	// Now start running the scheduler on this core.
 	schedulerLock.Lock()
diff --git a/src/runtime/runtime_rp2040.go b/src/runtime/runtime_rp2040.go
index 2ca3605e03..7a12900097 100644
--- a/src/runtime/runtime_rp2040.go
+++ b/src/runtime/runtime_rp2040.go
@@ -4,9 +4,32 @@ package runtime
 
 import (
 	"device/rp"
+	"runtime/interrupt"
 )
 
 const (
 	sioIrqFifoProc0 = rp.IRQ_SIO_IRQ_PROC0
 	sioIrqFifoProc1 = rp.IRQ_SIO_IRQ_PROC1
 )
+
+func enableSIOFifoInterruptCore0() {
+	intr := interrupt.New(sioIrqFifoProc0, func(intr interrupt.Interrupt) {
+		switch rp.SIO.FIFO_RD.Get() {
+		case 1:
+			gcInterruptHandler(0)
+		}
+	})
+	intr.Enable()
+	intr.SetPriority(0xff)
+}
+
+func enableSIOFifoInterruptCore1() {
+	intr := interrupt.New(sioIrqFifoProc1, func(intr interrupt.Interrupt) {
+		switch rp.SIO.FIFO_RD.Get() {
+		case 1:
+			gcInterruptHandler(1)
+		}
+	})
+	intr.Enable()
+	intr.SetPriority(0xff)
+}
diff --git a/src/runtime/runtime_rp2350.go b/src/runtime/runtime_rp2350.go
index 91af23212e..161847fc62 100644
--- a/src/runtime/runtime_rp2350.go
+++ b/src/runtime/runtime_rp2350.go
@@ -4,6 +4,7 @@ package runtime
 
 import (
 	"device/rp"
+	"runtime/interrupt"
 )
 
 const (
@@ -14,3 +15,22 @@ const (
 	sioIrqFifoProc0 = rp.IRQ_SIO_IRQ_FIFO
 	sioIrqFifoProc1 = rp.IRQ_SIO_IRQ_FIFO
 )
+
+var sioFifoInterrupt = interrupt.New(sioIrqFifoProc0, handleSIOFifoInterrupt)
+
+func enableSIOFifoInterruptCore0() {
+	sioFifoInterrupt.Enable()
+	sioFifoInterrupt.SetPriority(0xff)
+}
+
+func enableSIOFifoInterruptCore1() {
+	sioFifoInterrupt.Enable()
+	sioFifoInterrupt.SetPriority(0xff)
+}
+
+func handleSIOFifoInterrupt(intr interrupt.Interrupt) {
+	switch rp.SIO.FIFO_RD.Get() {
+	case 1:
+		gcInterruptHandler(currentCPU())
+	}
+}