arch/sh/include/asm/cmpxchg-llsc.h

   1 #ifndef __ASM_SH_CMPXCHG_LLSC_H
   2 #define __ASM_SH_CMPXCHG_LLSC_H
   3
   4 #include <linux/bitops.h>
   5 #include <asm/byteorder.h>
   6
   7 static inline unsigned long xchg_u32(volatile u32 *m, unsigned long val)
   8 {
   9         unsigned long retval;
  10         unsigned long tmp;
  11
  12         __asm__ __volatile__ (
  13                 "1:                                     \n\t"
  14                 "movli.l        @%2, %0 ! xchg_u32      \n\t"
  15                 "mov            %0, %1                  \n\t"
  16                 "mov            %3, %0                  \n\t"
  17                 "movco.l        %0, @%2                 \n\t"
  18                 "bf             1b                      \n\t"
  19                 "synco                                  \n\t"
  20                 : "=&z"(tmp), "=&r" (retval)
  21                 : "r" (m), "r" (val)
  22                 : "t", "memory"
  23         );
  24
  25         return retval;
  26 }
  27
  28 static inline unsigned long
  29 __cmpxchg_u32(volatile u32 *m, unsigned long old, unsigned long new)
  30 {
  31         unsigned long retval;
  32         unsigned long tmp;
  33
  34         __asm__ __volatile__ (
  35                 "1:                                             \n\t"
  36                 "movli.l        @%2, %0 ! __cmpxchg_u32         \n\t"
  37                 "mov            %0, %1                          \n\t"
  38                 "cmp/eq         %1, %3                          \n\t"
  39                 "bf             2f                              \n\t"
  40                 "mov            %4, %0                          \n\t"
  41                 "2:                                             \n\t"
  42                 "movco.l        %0, @%2                         \n\t"
  43                 "bf             1b                              \n\t"
  44                 "synco                                          \n\t"
  45                 : "=&z" (tmp), "=&r" (retval)
  46                 : "r" (m), "r" (old), "r" (new)
  47                 : "t", "memory"
  48         );
  49
  50         return retval;
  51 }
  52
  53 static inline u32 __xchg_cmpxchg(volatile void *ptr, u32 x, int size)
  54 {
  55         int off = (unsigned long)ptr % sizeof(u32);
  56         volatile u32 *p = ptr - off;
  57 #ifdef __BIG_ENDIAN
  58         int bitoff = (sizeof(u32) - 1 - off) * BITS_PER_BYTE;
  59 #else
  60         int bitoff = off * BITS_PER_BYTE;
  61 #endif
  62         u32 bitmask = ((0x1 << size * BITS_PER_BYTE) - 1) << bitoff;
  63         u32 oldv, newv;
  64         u32 ret;
  65
  66         do {
  67                 oldv = READ_ONCE(*p);
  68                 ret = (oldv & bitmask) >> bitoff;
  69                 newv = (oldv & ~bitmask) | (x << bitoff);
  70         } while (__cmpxchg_u32(p, oldv, newv) != oldv);
  71
  72         return ret;
  73 }
  74
  75 static inline unsigned long xchg_u16(volatile u16 *m, unsigned long val)
  76 {
  77         return __xchg_cmpxchg(m, val, sizeof *m);
  78 }
  79
  80 static inline unsigned long xchg_u8(volatile u8 *m, unsigned long val)
  81 {
  82         return __xchg_cmpxchg(m, val, sizeof *m);
  83 }
  84
  85 #endif /* __ASM_SH_CMPXCHG_LLSC_H */