From 92d7223a74235054f2aa7227d207d9c57f84dca0 Mon Sep 17 00:00:00 2001
From: Sinan Kaya <okaya@codeaurora.org>
Date: Mon, 16 Apr 2018 18:16:56 -0400
Subject: [PATCH] alpha: io: reorder barriers to guarantee writeX() and
iowriteX() ordering #2
memory-barriers.txt has been updated with the following requirement.
"When using writel(), a prior wmb() is not needed to guarantee that the
cache coherent memory writes have completed before writing to the MMIO
region."
Current writeX() and iowriteX() implementations on alpha are not
satisfying this requirement as the barrier is after the register write.
Move mb() in writeX() and iowriteX() functions to guarantee that HW
observes memory changes before performing register operations.
Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Matt Turner <mattst88@gmail.com>
---
arch/alpha/kernel/io.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/arch/alpha/kernel/io.c b/arch/alpha/kernel/io.c
index 3e3d49c254c52..c025a3e5e3578 100644
--- a/arch/alpha/kernel/io.c
+++ b/arch/alpha/kernel/io.c
@@ -37,20 +37,20 @@ unsigned int ioread32(void __iomem *addr)
void iowrite8(u8 b, void __iomem *addr)
{
- IO_CONCAT(__IO_PREFIX,iowrite8)(b, addr);
mb();
+ IO_CONCAT(__IO_PREFIX,iowrite8)(b, addr);
}
void iowrite16(u16 b, void __iomem *addr)
{
- IO_CONCAT(__IO_PREFIX,iowrite16)(b, addr);
mb();
+ IO_CONCAT(__IO_PREFIX,iowrite16)(b, addr);
}
void iowrite32(u32 b, void __iomem *addr)
{
- IO_CONCAT(__IO_PREFIX,iowrite32)(b, addr);
mb();
+ IO_CONCAT(__IO_PREFIX,iowrite32)(b, addr);
}
EXPORT_SYMBOL(ioread8);
@@ -176,26 +176,26 @@ u64 readq(const volatile void __iomem *addr)
void writeb(u8 b, volatile void __iomem *addr)
{
- __raw_writeb(b, addr);
mb();
+ __raw_writeb(b, addr);
}
void writew(u16 b, volatile void __iomem *addr)
{
- __raw_writew(b, addr);
mb();
+ __raw_writew(b, addr);
}
void writel(u32 b, volatile void __iomem *addr)
{
- __raw_writel(b, addr);
mb();
+ __raw_writel(b, addr);
}
void writeq(u64 b, volatile void __iomem *addr)
{
- __raw_writeq(b, addr);
mb();
+ __raw_writeq(b, addr);
}
EXPORT_SYMBOL(readb);
--
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