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/replacements.h>
  28 #include <helper/types.h>
  29
  30 #define BIT(nr)                     (1UL << (nr))
  31 #define BITS_PER_BYTE               8
  32 #define BITS_PER_LONG               (BITS_PER_BYTE * sizeof(long))
  33 #define BITS_TO_LONGS(nr)           DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long))
  34 #define BIT_MASK(nr)                (1UL << ((nr) % BITS_PER_LONG))
  35 #define BIT_WORD(nr)                ((nr) / BITS_PER_LONG)
  36 #define DECLARE_BITMAP(name, bits)  unsigned long name[BITS_TO_LONGS(bits)]
  37
  38 /**
  39  * bitmap_zero - Clears all the bits in memory
  40  * @param dst the address of the bitmap
  41  * @param nbits the number of bits to clear
  42  */
  43 static inline void bitmap_zero(unsigned long *dst, unsigned int nbits)
  44 {
  45         unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
  46         memset(dst, 0, len);
  47 }
  48
  49 /**
  50  * clear_bit - Clear a bit in memory
  51  * @param nr the bit to set
  52  * @param addr the address to start counting from
  53  */
  54 static inline void clear_bit(unsigned int nr, volatile unsigned long *addr)
  55 {
  56         unsigned long mask = BIT_MASK(nr);
  57         unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
  58
  59         *p &= ~mask;
  60 }
  61
  62 /**
  63  * set_bit - Set a bit in memory
  64  * @param nr the bit to set
  65  * @param addr the address to start counting from
  66  */
  67 static inline void set_bit(unsigned int nr, volatile unsigned long *addr)
  68 {
  69         unsigned long mask = BIT_MASK(nr);
  70         unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
  71
  72         *p |= mask;
  73 }
  74
  75 /**
  76  * test_bit - Determine whether a bit is set
  77  * @param nr bit number to test
  78  * @param addr Address to start counting from
  79  */
  80 static inline int test_bit(unsigned int nr, const volatile unsigned long *addr)
  81 {
  82         return 1UL & (addr[BIT_WORD(nr)] >> (nr % BITS_PER_LONG));
  83 }
  84
  85 #endif /* OPENOCD_HELPER_BITS_H */