From 169c474fb22d8a5e909e172f177b957546d0519d Mon Sep 17 00:00:00 2001 From: William Breathitt Gray Date: Wed, 4 Dec 2019 16:50:57 -0800 Subject: bitops: introduce the for_each_set_clump8 macro Pach series "Introduce the for_each_set_clump8 macro", v18. While adding GPIO get_multiple/set_multiple callback support for various drivers, I noticed a pattern of looping manifesting that would be useful standardized as a macro. This patchset introduces the for_each_set_clump8 macro and utilizes it in several GPIO drivers. The for_each_set_clump macro8 facilitates a for-loop syntax that iterates over a memory region entire groups of set bits at a time. For example, suppose you would like to iterate over a 32-bit integer 8 bits at a time, skipping over 8-bit groups with no set bit, where XXXXXXXX represents the current 8-bit group: Example: 10111110 00000000 11111111 00110011 First loop: 10111110 00000000 11111111 XXXXXXXX Second loop: 10111110 00000000 XXXXXXXX 00110011 Third loop: XXXXXXXX 00000000 11111111 00110011 Each iteration of the loop returns the next 8-bit group that has at least one set bit. The for_each_set_clump8 macro has four parameters: * start: set to the bit offset of the current clump * clump: set to the current clump value * bits: bitmap to search within * size: bitmap size in number of bits In this version of the patchset, the for_each_set_clump macro has been reimplemented and simplified based on the suggestions provided by Rasmus Villemoes and Andy Shevchenko in the version 4 submission. In particular, the function of the for_each_set_clump macro has been restricted to handle only 8-bit clumps; the drivers that use the for_each_set_clump macro only handle 8-bit ports so a generic for_each_set_clump implementation is not necessary. Thus, a solution for large clumps (i.e. those larger than the width of a bitmap word) can be postponed until a driver appears that actually requires such a generic for_each_set_clump implementation. For what it's worth, a semi-generic for_each_set_clump (i.e. for clumps smaller than the width of a bitmap word) can be implemented by simply replacing the hardcoded '8' and '0xFF' instances with respective variables. I have not yet had a need for such an implementation, and since it falls short of a true generic for_each_set_clump function, I have decided to forgo such an implementation for now. In addition, the bitmap_get_value8 and bitmap_set_value8 functions are introduced to get and set 8-bit values respectively. Their use is based on the behavior suggested in the patchset version 4 review. This patch (of 14): This macro iterates for each 8-bit group of bits (clump) with set bits, within a bitmap memory region. For each iteration, "start" is set to the bit offset of the found clump, while the respective clump value is stored to the location pointed by "clump". Additionally, the bitmap_get_value8 and bitmap_set_value8 functions are introduced to respectively get and set an 8-bit value in a bitmap memory region. [gustavo@embeddedor.com: fix potential sign-extension overflow] Link: http://lkml.kernel.org/r/20191015184657.GA26541@embeddedor [akpm@linux-foundation.org: s/ULL/UL/, per Joe] [vilhelm.gray@gmail.com: add for_each_set_clump8 documentation] Link: http://lkml.kernel.org/r/20191016161825.301082-1-vilhelm.gray@gmail.com Link: http://lkml.kernel.org/r/893c3b4f03266c9496137cc98ac2b1bd27f92c73.1570641097.git.vilhelm.gray@gmail.com Signed-off-by: William Breathitt Gray Signed-off-by: Gustavo A. R. Silva Suggested-by: Andy Shevchenko Suggested-by: Rasmus Villemoes Suggested-by: Lukas Wunner Tested-by: Andy Shevchenko Cc: Arnd Bergmann Cc: Linus Walleij Cc: Bartosz Golaszewski Cc: Masahiro Yamada Cc: Geert Uytterhoeven Cc: Phil Reid Cc: Geert Uytterhoeven Cc: Mathias Duckeck Cc: Morten Hein Tiljeset Cc: Sean Nyekjaer Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/bitmap.h | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) (limited to 'include/linux/bitmap.h') diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h index 29fc933df3bf..9f046609e809 100644 --- a/include/linux/bitmap.h +++ b/include/linux/bitmap.h @@ -66,6 +66,8 @@ * bitmap_allocate_region(bitmap, pos, order) Allocate specified bit region * bitmap_from_arr32(dst, buf, nbits) Copy nbits from u32[] buf to dst * bitmap_to_arr32(buf, src, nbits) Copy nbits from buf to u32[] dst + * bitmap_get_value8(map, start) Get 8bit value from map at start + * bitmap_set_value8(map, value, start) Set 8bit value to map at start * * Note, bitmap_zero() and bitmap_fill() operate over the region of * unsigned longs, that is, bits behind bitmap till the unsigned long @@ -489,6 +491,39 @@ static inline void bitmap_from_u64(unsigned long *dst, u64 mask) dst[1] = mask >> 32; } +/** + * bitmap_get_value8 - get an 8-bit value within a memory region + * @map: address to the bitmap memory region + * @start: bit offset of the 8-bit value; must be a multiple of 8 + * + * Returns the 8-bit value located at the @start bit offset within the @src + * memory region. + */ +static inline unsigned long bitmap_get_value8(const unsigned long *map, + unsigned long start) +{ + const size_t index = BIT_WORD(start); + const unsigned long offset = start % BITS_PER_LONG; + + return (map[index] >> offset) & 0xFF; +} + +/** + * bitmap_set_value8 - set an 8-bit value within a memory region + * @map: address to the bitmap memory region + * @value: the 8-bit value; values wider than 8 bits may clobber bitmap + * @start: bit offset of the 8-bit value; must be a multiple of 8 + */ +static inline void bitmap_set_value8(unsigned long *map, unsigned long value, + unsigned long start) +{ + const size_t index = BIT_WORD(start); + const unsigned long offset = start % BITS_PER_LONG; + + map[index] &= ~(0xFFUL << offset); + map[index] |= value << offset; +} + #endif /* __ASSEMBLY__ */ #endif /* __LINUX_BITMAP_H */ -- cgit v1.2.3 From 30544ed5de431fe25d3793e4dd5a058d877c4d77 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Wed, 4 Dec 2019 16:53:26 -0800 Subject: lib/bitmap: introduce bitmap_replace() helper In some drivers we want to have a single operation over bitmap which is an equivalent to: *dst = (*old & ~(*mask)) | (*new & *mask) Introduce bitmap_replace() helper for this. Link: http://lkml.kernel.org/r/20191022172922.61232-8-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko Acked-by: Linus Walleij Cc: Rasmus Villemoes Cc: Bartosz Golaszewski Cc: Geert Uytterhoeven Cc: Marek Vasut Cc: Thomas Petazzoni Cc: William Breathitt Gray Cc: Yury Norov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/bitmap.h | 16 ++++++++++++++++ lib/bitmap.c | 12 ++++++++++++ lib/test_bitmap.c | 38 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 66 insertions(+) (limited to 'include/linux/bitmap.h') diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h index 9f046609e809..ff335b22f23c 100644 --- a/include/linux/bitmap.h +++ b/include/linux/bitmap.h @@ -53,6 +53,7 @@ * bitmap_find_next_zero_area_off(buf, len, pos, n, mask) as above * bitmap_shift_right(dst, src, n, nbits) *dst = *src >> n * bitmap_shift_left(dst, src, n, nbits) *dst = *src << n + * bitmap_replace(dst, old, new, mask, nbits) *dst = (*old & ~(*mask)) | (*new & *mask) * bitmap_remap(dst, src, old, new, nbits) *dst = map(old, new)(src) * bitmap_bitremap(oldbit, old, new, nbits) newbit = map(old, new)(oldbit) * bitmap_onto(dst, orig, relmap, nbits) *dst = orig relative to relmap @@ -140,6 +141,9 @@ extern void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1, const unsigned long *bitmap2, unsigned int nbits); extern int __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1, const unsigned long *bitmap2, unsigned int nbits); +extern void __bitmap_replace(unsigned long *dst, + const unsigned long *old, const unsigned long *new, + const unsigned long *mask, unsigned int nbits); extern int __bitmap_intersects(const unsigned long *bitmap1, const unsigned long *bitmap2, unsigned int nbits); extern int __bitmap_subset(const unsigned long *bitmap1, @@ -434,6 +438,18 @@ static inline void bitmap_shift_left(unsigned long *dst, const unsigned long *sr __bitmap_shift_left(dst, src, shift, nbits); } +static inline void bitmap_replace(unsigned long *dst, + const unsigned long *old, + const unsigned long *new, + const unsigned long *mask, + unsigned int nbits) +{ + if (small_const_nbits(nbits)) + *dst = (*old & ~(*mask)) | (*new & *mask); + else + __bitmap_replace(dst, old, new, mask, nbits); +} + static inline int bitmap_parse(const char *buf, unsigned int buflen, unsigned long *maskp, int nmaskbits) { diff --git a/lib/bitmap.c b/lib/bitmap.c index f9e834841e94..4250519d7d1c 100644 --- a/lib/bitmap.c +++ b/lib/bitmap.c @@ -222,6 +222,18 @@ int __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1, } EXPORT_SYMBOL(__bitmap_andnot); +void __bitmap_replace(unsigned long *dst, + const unsigned long *old, const unsigned long *new, + const unsigned long *mask, unsigned int nbits) +{ + unsigned int k; + unsigned int nr = BITS_TO_LONGS(nbits); + + for (k = 0; k < nr; k++) + dst[k] = (old[k] & ~mask[k]) | (new[k] & mask[k]); +} +EXPORT_SYMBOL(__bitmap_replace); + int __bitmap_intersects(const unsigned long *bitmap1, const unsigned long *bitmap2, unsigned int bits) { diff --git a/lib/test_bitmap.c b/lib/test_bitmap.c index 4544847cf81e..e14a15ac250b 100644 --- a/lib/test_bitmap.c +++ b/lib/test_bitmap.c @@ -42,6 +42,19 @@ static const unsigned long exp2[] __initconst = { BITMAP_FROM_U64(0xffffffff77777777ULL), }; +/* Fibonacci sequence */ +static const unsigned long exp2_to_exp3_mask[] __initconst = { + BITMAP_FROM_U64(0x008000020020212eULL), +}; +/* exp3_0_1 = (exp2[0] & ~exp2_to_exp3_mask) | (exp2[1] & exp2_to_exp3_mask) */ +static const unsigned long exp3_0_1[] __initconst = { + BITMAP_FROM_U64(0x33b3333311313137ULL), +}; +/* exp3_1_0 = (exp2[1] & ~exp2_to_exp3_mask) | (exp2[0] & exp2_to_exp3_mask) */ +static const unsigned long exp3_1_0[] __initconst = { + BITMAP_FROM_U64(0xff7fffff77575751ULL), +}; + static bool __init __check_eq_uint(const char *srcfile, unsigned int line, const unsigned int exp_uint, unsigned int x) @@ -257,6 +270,30 @@ static void __init test_copy(void) expect_eq_pbl("0-108,128-1023", bmap2, 1024); } +#define EXP2_IN_BITS (sizeof(exp2) * 8) + +static void __init test_replace(void) +{ + unsigned int nbits = 64; + DECLARE_BITMAP(bmap, 1024); + + bitmap_zero(bmap, 1024); + bitmap_replace(bmap, &exp2[0], &exp2[1], exp2_to_exp3_mask, nbits); + expect_eq_bitmap(bmap, exp3_0_1, nbits); + + bitmap_zero(bmap, 1024); + bitmap_replace(bmap, &exp2[1], &exp2[0], exp2_to_exp3_mask, nbits); + expect_eq_bitmap(bmap, exp3_1_0, nbits); + + bitmap_fill(bmap, 1024); + bitmap_replace(bmap, &exp2[0], &exp2[1], exp2_to_exp3_mask, nbits); + expect_eq_bitmap(bmap, exp3_0_1, nbits); + + bitmap_fill(bmap, 1024); + bitmap_replace(bmap, &exp2[1], &exp2[0], exp2_to_exp3_mask, nbits); + expect_eq_bitmap(bmap, exp3_1_0, nbits); +} + #define PARSE_TIME 0x1 struct test_bitmap_parselist{ @@ -476,6 +513,7 @@ static void __init selftest(void) test_zero_clear(); test_fill_set(); test_copy(); + test_replace(); test_bitmap_arr32(); test_bitmap_parselist(); test_bitmap_parselist_user(); -- cgit v1.2.3