Message-ID: <20230921110424.215592-1-bhe@redhat.com>
Date:   Thu, 21 Sep 2023 19:04:20 +0800
From:   Baoquan He <bhe@...hat.com>
To:     linux-kernel@...r.kernel.org
Cc:     linux-arch@...r.kernel.org, linux-mm@...ck.org,
        akpm@...ux-foundation.org, arnd@...db.de, jiaxun.yang@...goat.com,
        mpe@...erman.id.au, geert@...ux-m68k.org, mcgrof@...nel.org,
        hch@...radead.org, tsbogend@...ha.franken.de, f.fainelli@...il.com,
        deller@....de, Baoquan He <bhe@...hat.com>
Subject: [PATCH v5 0/4] arch/*/io.h: remove ioremap_uc in some architectures

This patchset tries to remove ioremap_uc() in the current architectures
except of x86 and ia64. They will use the default ioremap_uc version
in <asm-generic/io.h> which returns NULL. Anyone who wants to add new
invocation of ioremap_uc(), please consider using ioremap() instead or
adding a new ARCH specific ioremap_uc(), or refer to the callsite
in drivers/video/fbdev/aty/atyfb_base.c.

This change won't cuase breakage to the current kernel because in the
only ioremap_uc callsite, an adjustment is made to eliminate impact in
patch 1 of this series.

To get rid of all of them other than x86 and ia64, add asm-generic/io.h
to asm/io.h of mips ARCH. With this adding, we can get rid of the
ioremap_uc() in mips too. This is done in patch 2. And a followup patch
4 is added to remove duplicated code according to Arnd's suggestion.

Test:
=====
Except of Jiaxun's efficient testing on patch 2/4, I also did cross compiling
of this series on mips64, building passed.

History:
=======
v4->v5:
  - In v4, Thomas reported that adding <asm-generic/io.h> including into
    mips always cause crash on his malta qemu. Finally, Jiaxun stood up to
    take over the patch 2/4 and make it work. This patchset collects
    Jiaxun's patch v5 and add Arnd's tag. Thanks to Jiaxun.
  - Meanwhile, the old patch 4/4 need be adjusted because Jiaxun has done
    some removal of duplicated codes in <asm/io.h>.
  - Add reviewers' tags from v4.
v3->v4:
  - Add patch 1 to adjust code in the only ioremap_uc() callsite so that
    later removing ioremap_uc() won't cause breakage.
  - Update log and document writing in patch 3.
  - Add followup patch 4 to clean up duplicated code in asm/io.h of MIPS.
v2->v3:
  - In patch 1, move those macro definition of functio near its function
    declaration according to Arnd's suggestion. And remove the unneeded
    change in asm/mmiowb.h introduced in old version.
  - In patch 2, clean up and rewrite the messy document related to
    ioremap_uc() in Documentation/driver-api/device-io.rst.
v1->v2:
  - Update log of patch 2, and document related to ioremap_uc()
    according to Geert's comment.
  - Add Geert's Acked-by.

Arnd Bergmann (1):
  video: fbdev: atyfb: only use ioremap_uc() on i386 and ia64

Baoquan He (2):
  arch/*/io.h: remove ioremap_uc in some architectures
  mips: io: remove duplicated codes

Jiaxun Yang (1):
  mips: add <asm-generic/io.h> including

 Documentation/driver-api/device-io.rst |   9 +-
 arch/alpha/include/asm/io.h            |   1 -
 arch/hexagon/include/asm/io.h          |   3 -
 arch/m68k/include/asm/kmap.h           |   1 -
 arch/mips/include/asm/io.h             | 123 +++++++++++++++----------
 arch/mips/include/asm/mmiowb.h         |   4 +-
 arch/mips/include/asm/smp-ops.h        |   2 -
 arch/mips/include/asm/smp.h            |   4 +-
 arch/mips/kernel/setup.c               |   1 +
 arch/mips/pci/pci-ip27.c               |   3 +
 arch/parisc/include/asm/io.h           |   2 -
 arch/powerpc/include/asm/io.h          |   1 -
 arch/sh/include/asm/io.h               |   2 -
 arch/sparc/include/asm/io_64.h         |   1 -
 drivers/video/fbdev/aty/atyfb_base.c   |   4 +
 15 files changed, 88 insertions(+), 73 deletions(-)

-- 
2.41.0

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