tree 9aaa4bc00bd7426abcd3456e099b0322adbe773a
parent 4ba6a2b28f111e4c9621487612056d10f3f4a6ca
parent 320549a22484952d88d4e0320218765b16cd2174
author Linus Torvalds <torvalds@linux-foundation.org> 1454955606 -0800
committer Linus Torvalds <torvalds@linux-foundation.org> 1454955606 -0800
mergetag object 320549a22484952d88d4e0320218765b16cd2174
 type commit
 tag regmap-fix-v4.5-big-endian
 tagger Mark Brown <broonie@kernel.org> 1454672083 +0000
 
 regmap: mmio: Revert to v4.4 endianness handling
 
 Commit 29bb45f25ff3 (regmap-mmio: Use native endianness for read/write)
 attempted to fix some long standing bugs in the MMIO implementation for
 big endian systems caused by duplicate byte swapping in both regmap and
 readl()/writel() which affected MIPS systems as when they are in big
 endian mode they flip the endianness of all registers in the system, not
 just the CPU.  MIPS systems had worked around this by declaring regmap
 using IPs as little endian which is inaccurate, unfortunately the issue
 had not been reported.
 
 Sadly the fix makes things worse rather than better.  By changing the
 behaviour to match the documentation it caused behaviour changes for
 other IPs which broke them and by using the __raw I/O accessors to avoid
 the endianness swapping in readl()/writel() it removed some memory
 ordering guarantees and could potentially generate unvirtualisable
 instructions on some architectures.
 
 Unfortunately sorting out all this mess in any half way sensible fashion
 was far too invasive to go in during an -rc cycle so instead let's go
 back to the old broken behaviour for v4.5, the better fixes are already
 queued for v4.6.  This does mean that we keep the broken MIPS DTs for
 another release but that seems the least bad way of handling the
 situation.
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1
 
 iQEcBAABAgAGBQJWtIjbAAoJECTWi3JdVIfQs8QH/jNpfio4klDkdlH/KpPZXlrp
 FzASbGePNtLqZXFL5WcG//ni3EYdbaiXZIdLBKDx9K4F2ca9FAF8aAnZAZ5uefGx
 bnloYpV34DqQwS5f9FrrNsm+YVTTuUIt0dx4ZRGCEdMTzW7i3efs/9eVEITUixK6
 U1obTJovAl33bihadsC9hzJVwfOq3H4aFFWc/EFZzbQaU2/so2eiA1dhPr/YErRJ
 dMR8drWxpYXuBsrk5T647R0sUw7pA4Zw+WAF032TPQf/1Fy9Vk1/yXbTyccZzFzo
 bfupRA/HpeLNZ9cN9z9y3Fa0je4UNbBZh0poB5B773af84NnhX7Ytenjo+peVxI=
 =+Q6E
 -----END PGP SIGNATURE-----

Merge tag 'regmap-fix-v4.5-big-endian' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap

Pull regmap fix from Mark Brown:
 "A single revert back to v4.4 endianness handling.

  Commit 29bb45f25ff3 ("regmap-mmio: Use native endianness for
  read/write") attempted to fix some long standing bugs in the MMIO
  implementation for big endian systems caused by duplicate byte
  swapping in both regmap and readl()/writel().  Sadly the fix makes
  things worse rather than better, so revert it for now"

* tag 'regmap-fix-v4.5-big-endian' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap:
  regmap: mmio: Revert to v4.4 endianness handling