src/helper/bits.h

   1 /*
   2  * Copyright (C) 2018, STMicroelectronics - All Rights Reserved
   3  * Author(s): Antonio Borneo <borneo.antonio@gmail.com> for STMicroelectronics
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 /*
  20  * The content of this file is mainly copied/inspired from Linux kernel
  21  * code in include/linux/types.h include/linux/bitmap.h include/linux/bitops.h
  22  */
  23
  24 #ifndef OPENOCD_HELPER_BITS_H
  25 #define OPENOCD_HELPER_BITS_H
  26
  27 #include <helper/types.h>
  28
  29 #define BIT(nr)                     (1UL << (nr))
  30 #define BITS_PER_BYTE               8
  31 #define BITS_PER_LONG               (BITS_PER_BYTE * sizeof(long))
  32 #define BITS_TO_LONGS(nr)           DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long))
  33 #define BIT_MASK(nr)                (1UL << ((nr) % BITS_PER_LONG))
  34 #define BIT_WORD(nr)                ((nr) / BITS_PER_LONG)
  35 #define DECLARE_BITMAP(name, bits)  unsigned long name[BITS_TO_LONGS(bits)]
  36
  37 /**
  38  * bitmap_zero - Clears all the bits in memory
  39  * @dst: the address of the bitmap
  40  * @nbits: the number of bits to clear
  41  */
  42 static inline void bitmap_zero(unsigned long *dst, unsigned int nbits)
  43 {
  44         unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
  45         memset(dst, 0, len);
  46 }
  47
  48 /**
  49  * clear_bit - Clear a bit in memory
  50  * @nr: the bit to set
  51  * @addr: the address to start counting from
  52  */
  53 static inline void clear_bit(unsigned int nr, volatile unsigned long *addr)
  54 {
  55         unsigned long mask = BIT_MASK(nr);
  56         unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
  57
  58         *p &= ~mask;
  59 }
  60
  61 /**
  62  * set_bit - Set a bit in memory
  63  * @nr: the bit to set
  64  * @addr: the address to start counting from
  65  */
  66 static inline void set_bit(unsigned int nr, volatile unsigned long *addr)
  67 {
  68         unsigned long mask = BIT_MASK(nr);
  69         unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
  70
  71         *p |= mask;
  72 }
  73
  74 /**
  75  * test_bit - Determine whether a bit is set
  76  * @nr: bit number to test
  77  * @addr: Address to start counting from
  78  */
  79 static inline int test_bit(unsigned int nr, const volatile unsigned long *addr)
  80 {
  81         return 1UL & (addr[BIT_WORD(nr)] >> (nr % BITS_PER_LONG));
  82 }
  83
  84 #endif /* OPENOCD_HELPER_BITS_H */