[v4,0/4] arch/*/io.h: remove ioremap_uc in some architectures

Message

Baoquan He March 8, 2023, 1:07 p.m. UTC

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.

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 (3):
  mips: add <asm-generic/io.h> including
  arch/*/io.h: remove ioremap_uc in some architectures
  mips: io: remove duplicated codes

 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             | 112 +++++++++++++++----------
 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 +
 10 files changed, 78 insertions(+), 58 deletions(-)