target/linux/generic/patches-4.4/087-regmap-make-LZO-cache-optional.patch

   1 From de88e9b0354c2e3ff8eae3f97afe43a34f5ed239 Mon Sep 17 00:00:00 2001
   2 From: Jonas Gorski <jonas.gorski@gmail.com>
   3 Date: Sat, 13 May 2017 13:03:21 +0200
   4 Subject: [PATCH] regmap: make LZO cache optional
   5
   6 Commit 2cbbb579bcbe3 ("regmap: Add the LZO cache support") added support
   7 for LZO compression in regcache, but there were never any users added
   8 afterwards. Since LZO support itself has its own size, it currently is
   9 rather a deoptimization.
  10
  11 So make it optional by introducing a symbol that can be selected by
  12 drivers wanting to make use of it.
  13
  14 Saves e.g. ~46 kB on MIPS (size of LZO support + regcache LZO code).
  15
  16 Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
  17 ---
  18 I tried using google to find any users (even out-of-tree ones), but at
  19 best I found a single driver submission that was switched to RBTREE in
  20 subsequent resubmissions (MFD_SMSC).
  21
  22 One could maybe also just drop the code because of no users for 5 years,
  23 but that would be up to the maintainer(s) to decide.
  24
  25  drivers/base/regmap/Kconfig    | 5 ++++-
  26  drivers/base/regmap/Makefile   | 3 ++-
  27  drivers/base/regmap/regcache.c | 2 ++
  28  3 files changed, 8 insertions(+), 2 deletions(-)
  29
  30 --- a/drivers/base/regmap/Kconfig
  31 +++ b/drivers/base/regmap/Kconfig
  32 @@ -4,9 +4,12 @@
  33
  34  config REGMAP
  35         default y if (REGMAP_I2C || REGMAP_SPI || REGMAP_SPMI || REGMAP_AC97 || REGMAP_MMIO || REGMAP_IRQ)
  36 +       select IRQ_DOMAIN if REGMAP_IRQ
  37 +       bool
  38 +
  39 +config REGCACHE_COMPRESSED
  40         select LZO_COMPRESS
  41         select LZO_DECOMPRESS
  42 -       select IRQ_DOMAIN if REGMAP_IRQ
  43         bool
  44
  45  config REGMAP_AC97
  46 --- a/drivers/base/regmap/Makefile
  47 +++ b/drivers/base/regmap/Makefile
  48 @@ -2,7 +2,8 @@
  49  CFLAGS_regmap.o := -I$(src)
  50
  51  obj-$(CONFIG_REGMAP) += regmap.o regcache.o
  52 -obj-$(CONFIG_REGMAP) += regcache-rbtree.o regcache-lzo.o regcache-flat.o
  53 +obj-$(CONFIG_REGMAP) += regcache-rbtree.o regcache-flat.o
  54 +obj-$(CONFIG_REGCACHE_COMPRESSED) += regcache-lzo.o
  55  obj-$(CONFIG_DEBUG_FS) += regmap-debugfs.o
  56  obj-$(CONFIG_REGMAP_AC97) += regmap-ac97.o
  57  obj-$(CONFIG_REGMAP_I2C) += regmap-i2c.o
  58 --- a/drivers/base/regmap/regcache.c
  59 +++ b/drivers/base/regmap/regcache.c
  60 @@ -21,7 +21,9 @@
  61
  62  static const struct regcache_ops *cache_types[] = {
  63         &regcache_rbtree_ops,
  64 +#if IS_ENABLED(CONFIG_REGCACHE_COMPRESSED)
  65         &regcache_lzo_ops,
  66 +#endif
  67         &regcache_flat_ops,
  68  };
  69