From 7d0b6ed05533c1a039dfc4988696151b551f60b2 Mon Sep 17 00:00:00 2001
From: tsutsui <tsutsui@NetBSD.org>
Date: Fri, 27 Jan 2023 15:31:05 +0000
Subject: [PATCH] next68k: Fix silent stall of next68k esp(4) SCSI.

next68k esp(4) driver requires nextdma(4) interrupts at ipl 6
during ncr53c9x_intr() for esp(4) at ipl 3.  It worked on netbsd-5
and prior, but on netbsd-5 splbio() was changed from ipl 3 to 6
for SMP support and on netbsd-6 ncr53c9x driver was changed to
use mutex(9) instead of simple_lock(9), so nextdma interrupts
were no longer raised during ncr53c9x interrupt handler.

For now, just call mutex_exit(9) and mutex_enter(9) during
waiting nextdma(4) interrupts in MD esp_dma_intr() handler.
This could be wrong and the interrupt handler for nextdma should
be reorganized, but it just works.

Should be pulled up to netbsd-10 and netbsd-9.
---
 sys/arch/next68k/dev/esp.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/sys/arch/next68k/dev/esp.c b/sys/arch/next68k/dev/esp.c
index 8f363729f40d..cfc85876ec37 100644
--- a/sys/arch/next68k/dev/esp.c
+++ b/sys/arch/next68k/dev/esp.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: esp.c,v 1.64 2017/03/31 08:38:13 msaitoh Exp $	*/
+/*	$NetBSD: esp.c,v 1.65 2023/01/27 15:31:05 tsutsui Exp $	*/
 
 /*-
  * Copyright (c) 1997, 1998 The NetBSD Foundation, Inc.
@@ -75,7 +75,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: esp.c,v 1.64 2017/03/31 08:38:13 msaitoh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: esp.c,v 1.65 2023/01/27 15:31:05 tsutsui Exp $");
 
 #include <sys/types.h>
 #include <sys/param.h>
@@ -509,6 +509,7 @@ esp_dma_intr(struct ncr53c9x_softc *sc)
 			}
 #endif
 
+			mutex_exit(&sc->sc_lock);	/* for nextdma intr */
 			while (!nextdma_finished(nsc)) {
 			/* esp_dma_isactive(sc)) { */
 				NDTRACEIF (ndtrace_addc('w'));
@@ -602,7 +603,7 @@ esp_dma_intr(struct ncr53c9x_softc *sc)
 
 			}
 		out:
-			;
+			mutex_enter(&sc->sc_lock);	/* for nextdma intr */
 
 #ifdef ESP_DEBUG
 /* 			esp_dma_nest--; */