io: Provide _inX() and _outX()

Since commit a7851aa ("io: change outX() to have their own IO barrier
overrides") and commit 87fe2d5 ("io: change inX() to have their own
IO barrier overrides"), the outX and inX functions have memory barriers
which can be overridden.

However, the generic logic_pio lib has continued to use readl/writel et al
for IO port accesses, which has weaker barriers on arm64.

Provide generic _inX() and _outX(), which can be used by logic pio.

For consistency, we check for !defined({in,out}X) && !defined(_{in,out}X),
for defining _{in,out}X, while a check for just !defined({in,out}X) should
suffice.

Reviewed-by: Arnd Bergmann <[email protected]>
Signed-off-by: John Garry <[email protected]>
Signed-off-by: Wei Xu <[email protected]>

Author: John Garry

include/asm-generic/io.h

@@ -448,17 +448,15 @@ static inline void writesq(volatile void __iomem *addr, const void *buffer,
 #define IO_SPACE_LIMIT 0xffff
 #endif
 
-#include <linux/logic_pio.h>
-
 /*
  * {in,out}{b,w,l}() access little endian I/O. {in,out}{b,w,l}_p() can be
  * implemented on hardware that needs an additional delay for I/O accesses to
  * take effect.
  */
 
-#ifndef inb
-#define inb inb
-static inline u8 inb(unsigned long addr)
+#if !defined(inb) && !defined(_inb)
+#define _inb _inb
+static inline u16 _inb(unsigned long addr)
 {
 	u8 val;
 
@@ -469,9 +467,9 @@ static inline u8 inb(unsigned long addr)
 }
 #endif
 
-#ifndef inw
-#define inw inw
-static inline u16 inw(unsigned long addr)
+#if !defined(inw) && !defined(_inw)
+#define _inw _inw
+static inline u16 _inw(unsigned long addr)
 {
 	u16 val;
 
@@ -482,9 +480,9 @@ static inline u16 inw(unsigned long addr)
 }
 #endif
 
-#ifndef inl
-#define inl inl
-static inline u32 inl(unsigned long addr)
+#if !defined(inl) && !defined(_inl)
+#define _inl _inl
+static inline u16 _inl(unsigned long addr)
 {
 	u32 val;
 
@@ -495,36 +493,62 @@ static inline u32 inl(unsigned long addr)
 }
 #endif
 
-#ifndef outb
-#define outb outb
-static inline void outb(u8 value, unsigned long addr)
+#if !defined(outb) && !defined(_outb)
+#define _outb _outb
+static inline void _outb(u8 value, unsigned long addr)
 {
 	__io_pbw();
 	__raw_writeb(value, PCI_IOBASE + addr);
 	__io_paw();
 }
 #endif
 
-#ifndef outw
-#define outw outw
-static inline void outw(u16 value, unsigned long addr)
+#if !defined(outw) && !defined(_outw)
+#define _outw _outw
+static inline void _outw(u16 value, unsigned long addr)
 {
 	__io_pbw();
 	__raw_writew(cpu_to_le16(value), PCI_IOBASE + addr);
 	__io_paw();
 }
 #endif
 
-#ifndef outl
-#define outl outl
-static inline void outl(u32 value, unsigned long addr)
+#if !defined(outl) && !defined(_outl)
+#define _outl _outl
+static inline void _outl(u32 value, unsigned long addr)
 {
 	__io_pbw();
 	__raw_writel(cpu_to_le32(value), PCI_IOBASE + addr);
 	__io_paw();
 }
 #endif
 
+#include <linux/logic_pio.h>
+
+#ifndef inb
+#define inb _inb
+#endif
+
+#ifndef inw
+#define inw _inw
+#endif
+
+#ifndef inl
+#define inl _inl
+#endif
+
+#ifndef outb
+#define outb _outb
+#endif
+
+#ifndef outw
+#define outw _outw
+#endif
+
+#ifndef outl
+#define outl _outl
+#endif
+
 #ifndef inb_p
 #define inb_p inb_p
 static inline u8 inb_p(unsigned long addr)