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2017-11-18include/linux/bitfield.h: include <linux/build_bug.h> instead of <linux/bug.h>Masahiro Yamada1-1/+1
Since commit bc6245e5efd7 ("bug: split BUILD_BUG stuff out into <linux/build_bug.h>"), #include <linux/build_bug.h> is better to pull minimal headers needed for BUILG_BUG() family. Link: http://lkml.kernel.org/r/1505700775-19826-1-git-send-email-yamada.masahiro@socionext.com Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com> Cc: Dinan Gunawardena <dinan.gunawardena@netronome.com> Cc: Kalle Valo <kvalo@codeaurora.org> Cc: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-04include/linux/bitfield.h: remove 32bit from FIELD_GET comment blockMasahiro Yamada1-1/+1
I do not see anything that restricts this macro to 32 bit width. Link: http://lkml.kernel.org/r/1505921975-23379-1-git-send-email-yamada.masahiro@socionext.com Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-10bitfield.h: add FIELD_FIT() helperJakub Kicinski1-0/+13
Add a helper for checking at runtime that a value will fit inside a specified field/mask. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-09add basic register-field manipulation macrosJakub Kicinski1-0/+93
Common approach to accessing register fields is to define structures or sets of macros containing mask and shift pair. Operations on the register are then performed as follows: field = (reg >> shift) & mask; reg &= ~(mask << shift); reg |= (field & mask) << shift; Defining shift and mask separately is tedious. Ivo van Doorn came up with an idea of computing them at compilation time based on a single shifted mask (later refined by Felix) which can be used like this: #define REG_FIELD 0x000ff000 field = FIELD_GET(REG_FIELD, reg); reg &= ~REG_FIELD; reg |= FIELD_PREP(REG_FIELD, field); FIELD_{GET,PREP} macros take care of finding out what the appropriate shift is based on compilation time ffs operation. GENMASK can be used to define registers (which is usually less error-prone and easier to match with datasheets). This approach is the most convenient I've seen so to limit code multiplication let's move the macros to a global header file. Attempts to use static inlines instead of macros failed due to false positive triggering of BUILD_BUG_ON()s, especially with GCC < 6.0. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Reviewed-by: Dinan Gunawardena <dinan.gunawardena@netronome.com> Signed-off-by: Kalle Valo <kvalo@codeaurora.org>