[PATCH v2] MIPS: OCTEON: Add WAR_OCTEON_BARRIER workaround config

[jiaqingtong97@163.com]

From: Jia Qingtong <jiaqingtong97@163.com>

Some Cavium Octeon CPUs(Octeon & Octeon Plus) suffer from a bug that
causes a single wmb ordering barrier to be ineffective, requiring
the use of 2 in sequence to provide an effective barrier.
This patch make workaroud as a config for CPUs who didn't suffer
from that bug.

Signed-off-by: Jia Qingtong <jiaqingtong97@163.com>
---
 arch/mips/cavium-octeon/Kconfig | 9 +++++++++
 arch/mips/include/asm/sync.h    | 2 +-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/arch/mips/cavium-octeon/Kconfig b/arch/mips/cavium-octeon/Kconfig
index 4984e462be30..0dc910683df9 100644
--- a/arch/mips/cavium-octeon/Kconfig
+++ b/arch/mips/cavium-octeon/Kconfig
@@ -1,6 +1,15 @@
 # SPDX-License-Identifier: GPL-2.0
 if CPU_CAVIUM_OCTEON
 
+config WAR_OCTEON_BARRIER
+	bool "Enable Octeon & Octeon Plus barrier workaround"
+	default "y"
+	help
+	  Some Cavium Octeon CPUs(Octeon & Octeon Plus)
+	  suffer from a bug that causes a single wmb ordering barrier
+	  to be ineffective, requiring the use of 2 in sequence
+	  to provide an effective barrier.
+
 config CAVIUM_CN63XXP1
 	bool "Enable CN63XXP1 errata workarounds"
 	default "n"
diff --git a/arch/mips/include/asm/sync.h b/arch/mips/include/asm/sync.h
index aabd097933fe..b24a2f82ef19 100644
--- a/arch/mips/include/asm/sync.h
+++ b/arch/mips/include/asm/sync.h
@@ -158,7 +158,7 @@
  * Note that this expression is evaluated by the assembler (not the compiler),
  * and that the assembler evaluates '==' as 0 or -1, not 0 or 1.
  */
-#ifdef CONFIG_CPU_CAVIUM_OCTEON
+#ifdef CONFIG_WAR_OCTEON_BARRIER
 # define __SYNC_rpt(type)	(1 - (type == __SYNC_wmb))
 #else
 # define __SYNC_rpt(type)	1
-- 
2.28.0