From 0823162211c1f13342183bcbfe322638e9a0e8d3 Mon Sep 17 00:00:00 2001
From: kettenis <kettenis@openbsd.org>
Date: Fri, 12 Nov 2021 17:04:32 +0000
Subject: [PATCH] Use a mutex to lock the bus such that we can safely access
 the bus from interrupt handlers and process context.

ok patrick@
---
 sys/arch/arm64/dev/aplspi.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/sys/arch/arm64/dev/aplspi.c b/sys/arch/arm64/dev/aplspi.c
index a9075636087..4bd1483adce 100644
--- a/sys/arch/arm64/dev/aplspi.c
+++ b/sys/arch/arm64/dev/aplspi.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: aplspi.c,v 1.1 2021/10/31 16:38:12 kettenis Exp $	*/
+/*	$OpenBSD: aplspi.c,v 1.2 2021/11/12 17:04:32 kettenis Exp $	*/
 /*
  * Copyright (c) 2021 Mark Kettenis <kettenis@openbsd.org>
  *
@@ -20,7 +20,7 @@
 #include <sys/kernel.h>
 #include <sys/device.h>
 #include <sys/malloc.h>
-#include <sys/stdint.h>
+#include <sys/mutex.h>
 
 #include <machine/bus.h>
 #include <machine/fdt.h>
@@ -63,6 +63,7 @@ struct aplspi_softc {
 	uint32_t		sc_pfreq;
 
 	struct spi_controller	sc_tag;
+	struct mutex		sc_mtx;
 
 	int			sc_cs;
 	uint32_t		*sc_csgpio;
@@ -145,6 +146,8 @@ aplspi_attach(struct device *parent, struct device *self, void *aux)
 	sc->sc_tag.sc_acquire_bus = aplspi_acquire_bus;
 	sc->sc_tag.sc_release_bus = aplspi_release_bus;
 
+	mtx_init(&sc->sc_mtx, IPL_TTY);
+
 	aplspi_scan(sc);
 }
 
@@ -245,12 +248,18 @@ aplspi_transfer(void *cookie, char *out, char *in, int len, int flags)
 int
 aplspi_acquire_bus(void *cookie, int flags)
 {
+	struct aplspi_softc *sc = cookie;
+
+	mtx_enter(&sc->sc_mtx);
 	return 0;
 }
 
 void
 aplspi_release_bus(void *cookie, int flags)
 {
+	struct aplspi_softc *sc = cookie;
+
+	mtx_leave(&sc->sc_mtx);
 }
 
 void
-- 
2.20.1