From 399b867fac244c4506f0a9365e7d53bfe74e66b4 Mon Sep 17 00:00:00 2001
From: Stefan Roese <sr@denx.de>
Date: Mon, 24 Aug 2020 13:04:41 +0200
Subject: [PATCH] mips: octeon: cache.c: Flush all pending writes in
 flush_dcache_range()

As noticed while working on the USB xHCI support, Octeon needs to flush
all pending writes so that the values are present in the memory. Add
this "syncw" instruction (twice) to flush_dcache_range().

Signed-off-by: Stefan Roese <sr@denx.de>
---
 arch/mips/mach-octeon/cache.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/mips/mach-octeon/cache.c b/arch/mips/mach-octeon/cache.c
index 9a88bb97c7..f293d65dae 100644
--- a/arch/mips/mach-octeon/cache.c
+++ b/arch/mips/mach-octeon/cache.c
@@ -5,14 +5,13 @@
 
 #include <cpu_func.h>
 
-/*
- * The Octeon platform is cache coherent and cache flushes and invalidates
- * are not needed. Define some platform specific empty flush_foo()
- * functions here to overwrite the _weak common function as a no-op.
- * This effectively disables all cache operations.
- */
+/* Octeon memory write barrier */
+#define CVMX_SYNCW	asm volatile ("syncw\nsyncw\n" : : : "memory")
+
 void flush_dcache_range(ulong start_addr, ulong stop)
 {
+	/* Flush all pending writes */
+	CVMX_SYNCW;
 }
 
 void flush_cache(ulong start_addr, ulong size)
@@ -21,4 +20,5 @@ void flush_cache(ulong start_addr, ulong size)
 
 void invalidate_dcache_range(ulong start_addr, ulong stop)
 {
+	/* Don't need to do anything for OCTEON */
 }
-- 
2.39.5