asm-generic/iomap.h: remove ARCH_HAS_IOREMAP_xx macros

Patch series "mm: ioremap: Convert architectures to take GENERIC_IOREMAP
way", v8.

Motivation and implementation:
==============================
Currently, many architecutres have't taken the standard GENERIC_IOREMAP
way to implement ioremap_prot(), iounmap(), and ioremap_xx(), but make
these functions specifically under each arch's folder.  Those cause many
duplicated code of ioremap() and iounmap().

In this patchset, firstly introduce generic_ioremap_prot() and
generic_iounmap() to extract the generic code for GENERIC_IOREMAP.  By
taking GENERIC_IOREMAP method, the generic generic_ioremap_prot(),
generic_iounmap(), and their generic wrapper ioremap_prot(), ioremap() and
iounmap() are all visible and available to arch.  Arch needs to provide
wrapper functions to override the generic version if there's arch specific
handling in its corresponding ioremap_prot(), ioremap() or iounmap(). 
With these changes, duplicated ioremap/iounmap() code uder ARCH-es are
removed, and the equivalent functioality is kept as before.

Background info:
================

1) The converting more architectures to take GENERIC_IOREMAP way is
   suggested by Christoph in below discussion:
   https://lore.kernel.org/all/[email protected]/T/#u

2) In the previous v1 to v3, it's basically further action after arm64
   has converted to GENERIC_IOREMAP way in below patchset.  It's done by
   adding hook ioremap_allowed() and iounmap_allowed() in ARCH to add ARCH
   specific handling the middle of ioremap_prot() and iounmap().

[PATCH v5 0/6] arm64: Cleanup ioremap() and support ioremap_prot()
https://lore.kernel.org/all/[email protected]/T/#u

Later, during v3 reviewing, Christophe Leroy suggested to introduce
generic_ioremap_prot() and generic_iounmap() to generic codes, and ARCH
can provide wrapper function ioremap_prot(), ioremap() or iounmap() if
needed.  Christophe made a RFC patchset as below to specially demonstrate
his idea.  This is what v4 and now v5 is doing.

[RFC PATCH 0/8] mm: ioremap: Convert architectures to take GENERIC_IOREMAP way
https://lore.kernel.org/all/[email protected]/T/#u

Testing:
========
In v8, I only applied this patchset onto the latest linus's tree to build
and run on arm64 and s390.


This patch (of 19):

Let's use '#define ioremap_xx' and "#ifdef ioremap_xx" instead.

To remove defined ARCH_HAS_IOREMAP_xx macros in <asm/io.h> of each ARCH,
the ARCH's own ioremap_wc|wt|np definition need be above "#include
<asm-generic/iomap.h>.  Otherwise the redefinition error would be seen
during compiling.  So the relevant adjustments are made to avoid compiling
error:

  loongarch:
  - doesn't include <asm-generic/iomap.h>, defining ARCH_HAS_IOREMAP_WC
    is redundant, so simply remove it.

  m68k:
  - selected GENERIC_IOMAP, <asm-generic/iomap.h> has been added in
    <asm-generic/io.h>, and <asm/kmap.h> is included above
    <asm-generic/iomap.h>, so simply remove ARCH_HAS_IOREMAP_WT defining.

  mips:
  - move "#include <asm-generic/iomap.h>" below ioremap_wc definition
    in <asm/io.h>

  powerpc:
  - remove "#include <asm-generic/iomap.h>" in <asm/io.h> because it's
    duplicated with the one in <asm-generic/io.h>, let's rely on the
    latter.

  x86:
  - selected GENERIC_IOMAP, remove #include <asm-generic/iomap.h> in
    the middle of <asm/io.h>. Let's rely on <asm-generic/io.h>.

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

1 files changed, 1 insertions, 8 deletions

diff --git a/arch/powerpc/include/asm/io.h b/arch/powerpc/include/asm/io.h
index f1e657c9bbe8..67a3fb6de498 100644
--- a/arch/powerpc/include/asm/io.h
+++ b/arch/powerpc/include/asm/io.h
@@ -3,11 +3,6 @@
 #define _ASM_POWERPC_IO_H
 #ifdef __KERNEL__
 
-#define ARCH_HAS_IOREMAP_WC
-#ifdef CONFIG_PPC32
-#define ARCH_HAS_IOREMAP_WT
-#endif
-
 /*
  */
 
@@ -732,9 +727,7 @@ static inline void name at					\
 #define writel_relaxed(v, addr)	writel(v, addr)
 #define writeq_relaxed(v, addr)	writeq(v, addr)
 
-#ifdef CONFIG_GENERIC_IOMAP
-#include <asm-generic/iomap.h>
-#else
+#ifndef CONFIG_GENERIC_IOMAP
 /*
  * Here comes the implementation of the IOMAP interfaces.
  */