linux/include/asm-generic/iomap.h
Baoquan He 0b1f77e74b 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/Yp7h0Jv6vpgt6xdZ@infradead.org/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/20220607125027.44946-1-wangkefeng.wang@huawei.com/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/cover.1665568707.git.christophe.leroy@csgroup.eu/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/20230706154520.11257-2-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: David Laight <David.Laight@ACULAB.COM>
Cc: Helge Deller <deller@gmx.de>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Brian Cain <bcain@quicinc.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Rich Felker <dalias@libc.org>
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>
2023-08-18 10:12:32 -07:00

116 lines
3.9 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __GENERIC_IO_H
#define __GENERIC_IO_H
#include <linux/linkage.h>
#include <asm/byteorder.h>
/*
* These are the "generic" interfaces for doing new-style
* memory-mapped or PIO accesses. Architectures may do
* their own arch-optimized versions, these just act as
* wrappers around the old-style IO register access functions:
* read[bwl]/write[bwl]/in[bwl]/out[bwl]
*
* Don't include this directly, include it from <asm/io.h>.
*/
/*
* Read/write from/to an (offsettable) iomem cookie. It might be a PIO
* access or a MMIO access, these functions don't care. The info is
* encoded in the hardware mapping set up by the mapping functions
* (or the cookie itself, depending on implementation and hw).
*
* The generic routines just encode the PIO/MMIO as part of the
* cookie, and coldly assume that the MMIO IO mappings are not
* in the low address range. Architectures for which this is not
* true can't use this generic implementation.
*/
extern unsigned int ioread8(const void __iomem *);
extern unsigned int ioread16(const void __iomem *);
extern unsigned int ioread16be(const void __iomem *);
extern unsigned int ioread32(const void __iomem *);
extern unsigned int ioread32be(const void __iomem *);
#ifdef CONFIG_64BIT
extern u64 ioread64(const void __iomem *);
extern u64 ioread64be(const void __iomem *);
#endif
#ifdef readq
#define ioread64_lo_hi ioread64_lo_hi
#define ioread64_hi_lo ioread64_hi_lo
#define ioread64be_lo_hi ioread64be_lo_hi
#define ioread64be_hi_lo ioread64be_hi_lo
extern u64 ioread64_lo_hi(const void __iomem *addr);
extern u64 ioread64_hi_lo(const void __iomem *addr);
extern u64 ioread64be_lo_hi(const void __iomem *addr);
extern u64 ioread64be_hi_lo(const void __iomem *addr);
#endif
extern void iowrite8(u8, void __iomem *);
extern void iowrite16(u16, void __iomem *);
extern void iowrite16be(u16, void __iomem *);
extern void iowrite32(u32, void __iomem *);
extern void iowrite32be(u32, void __iomem *);
#ifdef CONFIG_64BIT
extern void iowrite64(u64, void __iomem *);
extern void iowrite64be(u64, void __iomem *);
#endif
#ifdef writeq
#define iowrite64_lo_hi iowrite64_lo_hi
#define iowrite64_hi_lo iowrite64_hi_lo
#define iowrite64be_lo_hi iowrite64be_lo_hi
#define iowrite64be_hi_lo iowrite64be_hi_lo
extern void iowrite64_lo_hi(u64 val, void __iomem *addr);
extern void iowrite64_hi_lo(u64 val, void __iomem *addr);
extern void iowrite64be_lo_hi(u64 val, void __iomem *addr);
extern void iowrite64be_hi_lo(u64 val, void __iomem *addr);
#endif
/*
* "string" versions of the above. Note that they
* use native byte ordering for the accesses (on
* the assumption that IO and memory agree on a
* byte order, and CPU byteorder is irrelevant).
*
* They do _not_ update the port address. If you
* want MMIO that copies stuff laid out in MMIO
* memory across multiple ports, use "memcpy_toio()"
* and friends.
*/
extern void ioread8_rep(const void __iomem *port, void *buf, unsigned long count);
extern void ioread16_rep(const void __iomem *port, void *buf, unsigned long count);
extern void ioread32_rep(const void __iomem *port, void *buf, unsigned long count);
extern void iowrite8_rep(void __iomem *port, const void *buf, unsigned long count);
extern void iowrite16_rep(void __iomem *port, const void *buf, unsigned long count);
extern void iowrite32_rep(void __iomem *port, const void *buf, unsigned long count);
#ifdef CONFIG_HAS_IOPORT_MAP
/* Create a virtual mapping cookie for an IO port range */
extern void __iomem *ioport_map(unsigned long port, unsigned int nr);
extern void ioport_unmap(void __iomem *);
#endif
#ifndef ioremap_wc
#define ioremap_wc ioremap
#endif
#ifndef ioremap_wt
#define ioremap_wt ioremap
#endif
#ifndef ioremap_np
/* See the comment in asm-generic/io.h about ioremap_np(). */
#define ioremap_np ioremap_np
static inline void __iomem *ioremap_np(phys_addr_t offset, size_t size)
{
return NULL;
}
#endif
#include <asm-generic/pci_iomap.h>
#endif