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/20230706154520.11257-6-bhe@redhat.comSigned-off-by: Baoquan He <bhe@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Brian Cain <bcain@quicinc.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Chris Zankel <chris@zankel.net>
Cc: David Laight <David.Laight@ACULAB.COM>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Rich Felker <dalias@libc.org>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

include/asm-generic/io.h

@@ -1081,11 +1081,14 @@ void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size,
 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

@@ -46,12 +46,14 @@ void __iomem *generic_ioremap_prot(phys_addr_t phys_addr, size_t size,
 	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)
 {
@@ -64,8 +66,10 @@ void generic_iounmap(volatile void __iomem *addr)
 		vunmap(vaddr);
 }
 
+#ifndef iounmap
 void iounmap(volatile void __iomem *addr)
 {
 	generic_iounmap(addr);
 }
 EXPORT_SYMBOL(iounmap);
+#endif