src/helper/bits.h

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2
   3 /*
   4  * Copyright (C) 2018, STMicroelectronics - All Rights Reserved
   5  * Author(s): Antonio Borneo <borneo.antonio@gmail.com> for STMicroelectronics
   6  */
   7
   8 /*
   9  * The content of this file is mainly copied/inspired from Linux kernel
  10  * code in include/linux/types.h include/linux/bitmap.h include/linux/bitops.h
  11  */
  12
  13 #ifndef OPENOCD_HELPER_BITS_H
  14 #define OPENOCD_HELPER_BITS_H
  15
  16 #include <helper/replacements.h>
  17 #include <helper/types.h>
  18
  19 #define BIT(nr)                     (1UL << (nr))
  20 #define BIT_ULL(nr)                 (1ULL << (nr))
  21 #define BITS_PER_BYTE               8
  22 #define BITS_PER_LONG               (BITS_PER_BYTE * sizeof(long))
  23 #define BITS_PER_LONG_LONG          (BITS_PER_BYTE * sizeof(long long))
  24 #define GENMASK(h, l)               (((~0UL) - (1UL << (l)) + 1) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
  25 #define GENMASK_ULL(h, l)           (((~0ULL) - (1ULL << (l)) + 1) & (~0ULL >> (BITS_PER_LONG_LONG - 1 - (h))))
  26 #define BITS_TO_LONGS(nr)           DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long))
  27 #define BIT_MASK(nr)                (1UL << ((nr) % BITS_PER_LONG))
  28 #define BIT_WORD(nr)                ((nr) / BITS_PER_LONG)
  29 #define DECLARE_BITMAP(name, bits)  unsigned long name[BITS_TO_LONGS(bits)]
  30
  31 /**
  32  * bitmap_zero - Clears all the bits in memory
  33  * @param dst the address of the bitmap
  34  * @param nbits the number of bits to clear
  35  */
  36 static inline void bitmap_zero(unsigned long *dst, unsigned int nbits)
  37 {
  38         unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
  39         memset(dst, 0, len);
  40 }
  41
  42 /**
  43  * clear_bit - Clear a bit in memory
  44  * @param nr the bit to set
  45  * @param addr the address to start counting from
  46  */
  47 static inline void clear_bit(unsigned int nr, volatile unsigned long *addr)
  48 {
  49         unsigned long mask = BIT_MASK(nr);
  50         unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
  51
  52         *p &= ~mask;
  53 }
  54
  55 /**
  56  * set_bit - Set a bit in memory
  57  * @param nr the bit to set
  58  * @param addr the address to start counting from
  59  */
  60 static inline void set_bit(unsigned int nr, volatile unsigned long *addr)
  61 {
  62         unsigned long mask = BIT_MASK(nr);
  63         unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
  64
  65         *p |= mask;
  66 }
  67
  68 /**
  69  * test_bit - Determine whether a bit is set
  70  * @param nr bit number to test
  71  * @param addr Address to start counting from
  72  */
  73 static inline int test_bit(unsigned int nr, const volatile unsigned long *addr)
  74 {
  75         return 1UL & (addr[BIT_WORD(nr)] >> (nr % BITS_PER_LONG));
  76 }
  77
  78 #endif /* OPENOCD_HELPER_BITS_H */