Module Name: src
Committed By: skrll
Date: Mon Dec 14 19:32:29 UTC 2020
Modified Files:
src/sys/arch/aarch64/aarch64: bus_space.c
Log Message:
Add a note about completion vs ordering barrier as well.
To generate a diff of this commit:
cvs rdiff -u -r1.14 -r1.15 src/sys/arch/aarch64/aarch64/bus_space.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/arch/aarch64/aarch64/bus_space.c
diff -u src/sys/arch/aarch64/aarch64/bus_space.c:1.14 src/sys/arch/aarch64/aarch64/bus_space.c:1.15
--- src/sys/arch/aarch64/aarch64/bus_space.c:1.14 Mon Dec 14 19:25:28 2020
+++ src/sys/arch/aarch64/aarch64/bus_space.c Mon Dec 14 19:32:29 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: bus_space.c,v 1.14 2020/12/14 19:25:28 skrll Exp $ */
+/* $NetBSD: bus_space.c,v 1.15 2020/12/14 19:32:29 skrll Exp $ */
/*
* Copyright (c) 2017 Ryo Shimizu <[email protected]>
@@ -27,7 +27,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(1, "$NetBSD: bus_space.c,v 1.14 2020/12/14 19:25:28 skrll Exp $");
+__KERNEL_RCSID(1, "$NetBSD: bus_space.c,v 1.15 2020/12/14 19:32:29 skrll Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@@ -638,6 +638,10 @@ generic_bs_barrier(void *t, bus_space_ha
* consulting the page tables), so just issue the barrier
* unconditionally. Chances are either it's necessary or the
* cost is small in comparison to device register I/O.
+ *
+ * The bus_space(9) man page is not clear whether barriers
+ * should enforce ordering or completion. To be safe, use dsb
+ * (ensure completion) here instead of dmb (ordering).
*/
switch (flags) {
case BUS_SPACE_BARRIER_READ:
