include/asm-cris/bitops.h

   1 /* asm/bitops.h for Linux/CRIS
   2  *
   3  * TODO: asm versions if speed is needed
   4  *
   5  * All bit operations return 0 if the bit was cleared before the
   6  * operation and != 0 if it was not.
   7  *
   8  * bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1).
   9  */
  10
  11 #ifndef _CRIS_BITOPS_H
  12 #define _CRIS_BITOPS_H
  13
  14 /* Currently this is unsuitable for consumption outside the kernel.  */
  15 #ifdef __KERNEL__
  16
  17 #include <asm/arch/bitops.h>
  18 #include <asm/system.h>
  19 #include <asm/atomic.h>
  20 #include <linux/compiler.h>
  21
  22 /*
  23  * Some hacks to defeat gcc over-optimizations..
  24  */
  25 struct __dummy { unsigned long a[100]; };
  26 #define ADDR (*(struct __dummy *) addr)
  27 #define CONST_ADDR (*(const struct __dummy *) addr)
  28
  29 /*
  30  * set_bit - Atomically set a bit in memory
  31  * @nr: the bit to set
  32  * @addr: the address to start counting from
  33  *
  34  * This function is atomic and may not be reordered.  See __set_bit()
  35  * if you do not require the atomic guarantees.
  36  * Note that @nr may be almost arbitrarily large; this function is not
  37  * restricted to acting on a single-word quantity.
  38  */
  39
  40 #define set_bit(nr, addr)    (void)test_and_set_bit(nr, addr)
  41
  42 /*
  43  * clear_bit - Clears a bit in memory
  44  * @nr: Bit to clear
  45  * @addr: Address to start counting from
  46  *
  47  * clear_bit() is atomic and may not be reordered.  However, it does
  48  * not contain a memory barrier, so if it is used for locking purposes,
  49  * you should call smp_mb__before_clear_bit() and/or smp_mb__after_clear_bit()
  50  * in order to ensure changes are visible on other processors.
  51  */
  52
  53 #define clear_bit(nr, addr)  (void)test_and_clear_bit(nr, addr)
  54
  55 /*
  56  * change_bit - Toggle a bit in memory
  57  * @nr: Bit to change
  58  * @addr: Address to start counting from
  59  *
  60  * change_bit() is atomic and may not be reordered.
  61  * Note that @nr may be almost arbitrarily large; this function is not
  62  * restricted to acting on a single-word quantity.
  63  */
  64
  65 #define change_bit(nr, addr) (void)test_and_change_bit(nr, addr)
  66
  67 /**
  68  * test_and_set_bit - Set a bit and return its old value
  69  * @nr: Bit to set
  70  * @addr: Address to count from
  71  *
  72  * This operation is atomic and cannot be reordered.
  73  * It also implies a memory barrier.
  74  */
  75
  76 static inline int test_and_set_bit(int nr, volatile unsigned long *addr)
  77 {
  78         unsigned int mask, retval;
  79         unsigned long flags;
  80         unsigned int *adr = (unsigned int *)addr;
  81
  82         adr += nr >> 5;
  83         mask = 1 << (nr & 0x1f);
  84         cris_atomic_save(addr, flags);
  85         retval = (mask & *adr) != 0;
  86         *adr |= mask;
  87         cris_atomic_restore(addr, flags);
  88         return retval;
  89 }
  90
  91 /*
  92  * clear_bit() doesn't provide any barrier for the compiler.
  93  */
  94 #define smp_mb__before_clear_bit()      barrier()
  95 #define smp_mb__after_clear_bit()       barrier()
  96
  97 /**
  98  * test_and_clear_bit - Clear a bit and return its old value
  99  * @nr: Bit to clear
 100  * @addr: Address to count from
 101  *
 102  * This operation is atomic and cannot be reordered.
 103  * It also implies a memory barrier.
 104  */
 105
 106 static inline int test_and_clear_bit(int nr, volatile unsigned long *addr)
 107 {
 108         unsigned int mask, retval;
 109         unsigned long flags;
 110         unsigned int *adr = (unsigned int *)addr;
 111
 112         adr += nr >> 5;
 113         mask = 1 << (nr & 0x1f);
 114         cris_atomic_save(addr, flags);
 115         retval = (mask & *adr) != 0;
 116         *adr &= ~mask;
 117         cris_atomic_restore(addr, flags);
 118         return retval;
 119 }
 120
 121 /**
 122  * test_and_change_bit - Change a bit and return its old value
 123  * @nr: Bit to change
 124  * @addr: Address to count from
 125  *
 126  * This operation is atomic and cannot be reordered.
 127  * It also implies a memory barrier.
 128  */
 129
 130 static inline int test_and_change_bit(int nr, volatile unsigned long *addr)
 131 {
 132         unsigned int mask, retval;
 133         unsigned long flags;
 134         unsigned int *adr = (unsigned int *)addr;
 135         adr += nr >> 5;
 136         mask = 1 << (nr & 0x1f);
 137         cris_atomic_save(addr, flags);
 138         retval = (mask & *adr) != 0;
 139         *adr ^= mask;
 140         cris_atomic_restore(addr, flags);
 141         return retval;
 142 }
 143
 144 #include <asm-generic/bitops/non-atomic.h>
 145
 146 /*
 147  * Since we define it "external", it collides with the built-in
 148  * definition, which doesn't have the same semantics.  We don't want to
 149  * use -fno-builtin, so just hide the name ffs.
 150  */
 151 #define ffs kernel_ffs
 152
 153 #include <asm-generic/bitops/fls.h>
 154 #include <asm-generic/bitops/fls64.h>
 155 #include <asm-generic/bitops/hweight.h>
 156 #include <asm-generic/bitops/find.h>
 157
 158 #include <asm-generic/bitops/ext2-non-atomic.h>
 159
 160 #define ext2_set_bit_atomic(l,n,a)   test_and_set_bit(n,a)
 161 #define ext2_clear_bit_atomic(l,n,a) test_and_clear_bit(n,a)
 162
 163 #include <asm-generic/bitops/minix.h>
 164 #include <asm-generic/bitops/sched.h>
 165
 166 #endif /* __KERNEL__ */
 167
 168 #endif /* _CRIS_BITOPS_H */