mm: ioremap: allow ARCH to have its own ioremap method definition

Architectures can be converted to GENERIC_IOREMAP, to take standard
ioremap_xxx() and iounmap() way. But some ARCH-es could have specific
handling for ioremap_prot(), ioremap() and iounmap(), than standard
methods.

In oder to convert these ARCH-es to take GENERIC_IOREMAP method, allow
these architecutres to have their own ioremap_prot(), ioremap() and
iounmap() definitions.

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Baoquan He <[e-mail]>
Acked-by: Arnd Bergmann <[e-mail]>
Reviewed-by: Christoph Hellwig <[e-mail]>
Reviewed-by: Kefeng Wang <[e-mail]>
Reviewed-by: Mike Rapoport (IBM) <[e-mail]>
Cc: Alexander Gordeev <[e-mail]>
Cc: Brian Cain <[e-mail]>
Cc: Catalin Marinas <[e-mail]>
Cc: Christian Borntraeger <[e-mail]>
Cc: Christophe Leroy <[e-mail]>
Cc: Chris Zankel <[e-mail]>
Cc: David Laight <[e-mail]>
Cc: Geert Uytterhoeven <[e-mail]>
Cc: Gerald Schaefer <[e-mail]>
Cc: Heiko Carstens <[e-mail]>
Cc: Helge Deller <[e-mail]>
Cc: "James E.J. Bottomley" <[e-mail]>
Cc: John Paul Adrian Glaubitz <[e-mail]>
Cc: Jonas Bonn <[e-mail]>
Cc: Matthew Wilcox <[e-mail]>
Cc: Max Filippov <[e-mail]>
Cc: Michael Ellerman <[e-mail]>
Cc: Nathan Chancellor <[e-mail]>
Cc: Nicholas Piggin <[e-mail]>
Cc: Niklas Schnelle <[e-mail]>
Cc: Rich Felker <[e-mail]>
Cc: Stafford Horne <[e-mail]>
Cc: Stefan Kristiansson <[e-mail]>
Cc: Sven Schnelle <[e-mail]>
Cc: Vasily Gorbik <[e-mail]>
Cc: Vineet Gupta <[e-mail]>
Cc: Will Deacon <[e-mail]>
Cc: Yoshinori Sato <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

include/asm-generic/io.h

···
 void iounmap(volatile void __iomem *addr);
 void generic_iounmap(volatile void __iomem *addr);
 
+#ifndef ioremap
+#define ioremap ioremap
 static inline void __iomem *ioremap(phys_addr_t addr, size_t size)
 {
 	/* _PAGE_IOREMAP needs to be supplied by the architecture */
 	return ioremap_prot(addr, size, _PAGE_IOREMAP);
 }
+#endif
 #endif /* !CONFIG_MMU || CONFIG_GENERIC_IOREMAP */
 
 #ifndef ioremap_wc

mm/ioremap.c

···
 	return (void __iomem *)(vaddr + offset);
 }
 
+#ifndef ioremap_prot
 void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size,
 			   unsigned long prot)
 {
 	return generic_ioremap_prot(phys_addr, size, __pgprot(prot));
 }
 EXPORT_SYMBOL(ioremap_prot);
+#endif
 
 void generic_iounmap(volatile void __iomem *addr)
 {
···
 		vunmap(vaddr);
 }
 
+#ifndef iounmap
 void iounmap(volatile void __iomem *addr)
 {
 	generic_iounmap(addr);
 }
 EXPORT_SYMBOL(iounmap);
+#endif