io: change readX_relaxed() to remove barriers
authorSinan Kaya <okaya@codeaurora.org>
Fri, 6 Apr 2018 18:02:45 +0000 (14:02 -0400)
committerArnd Bergmann <arnd@arndb.de>
Tue, 10 Apr 2018 14:37:21 +0000 (16:37 +0200)
Now that we hardened readX() API in asm-generic version, readX_relaxed()
API is violating the rules when readX_relaxed() == readX() in the default
implementation.

The relaxed API shouldn't have any barriers in it and it doesn't provide
any ordering with respect to the memory transactions. The only requirement
is for reads to be ordered with respect to each other. This is achieved
by the volatile in the __raw_readX() API.

Open code the relaxed API and remove any barriers in it.

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
include/asm-generic/io.h

index 578b6883dd6ab08833de09dfba862395dfd9063e..fa0975da0cecbb115b6dccb231059b96d20b79e7 100644 (file)
@@ -252,19 +252,35 @@ static inline void writeq(u64 value, volatile void __iomem *addr)
  * accesses.
  */
 #ifndef readb_relaxed
-#define readb_relaxed readb
+#define readb_relaxed readb_relaxed
+static inline u8 readb_relaxed(const volatile void __iomem *addr)
+{
+       return __raw_readb(addr);
+}
 #endif
 
 #ifndef readw_relaxed
-#define readw_relaxed readw
+#define readw_relaxed readw_relaxed
+static inline u16 readw_relaxed(const volatile void __iomem *addr)
+{
+       return __le16_to_cpu(__raw_readw(addr));
+}
 #endif
 
 #ifndef readl_relaxed
-#define readl_relaxed readl
+#define readl_relaxed readl_relaxed
+static inline u32 readl_relaxed(const volatile void __iomem *addr)
+{
+       return __le32_to_cpu(__raw_readl(addr));
+}
 #endif
 
 #if defined(readq) && !defined(readq_relaxed)
-#define readq_relaxed readq
+#define readq_relaxed readq_relaxed
+static inline u64 readq_relaxed(const volatile void __iomem *addr)
+{
+       return __le64_to_cpu(__raw_readq(addr));
+}
 #endif
 
 #ifndef writeb_relaxed