include/asm-xtensa/system.h

   1 /*
   2  * include/asm-xtensa/system.h
   3  *
   4  * This file is subject to the terms and conditions of the GNU General Public
   5  * License.  See the file "COPYING" in the main directory of this archive
   6  * for more details.
   7  *
   8  * Copyright (C) 2001 - 2005 Tensilica Inc.
   9  */
  10
  11 #ifndef _XTENSA_SYSTEM_H
  12 #define _XTENSA_SYSTEM_H
  13
  14 #include <linux/stringify.h>
  15
  16 #include <asm/processor.h>
  17
  18 /* interrupt control */
  19
  20 #define local_save_flags(x)                                             \
  21         __asm__ __volatile__ ("rsr %0,"__stringify(PS) : "=a" (x));
  22 #define local_irq_restore(x)    do {                                    \
  23         __asm__ __volatile__ ("wsr %0, "__stringify(PS)" ; rsync"       \
  24                               :: "a" (x) : "memory"); } while(0);
  25 #define local_irq_save(x)       do {                                    \
  26         __asm__ __volatile__ ("rsil %0, "__stringify(LOCKLEVEL)         \
  27                               : "=a" (x) :: "memory");} while(0);
  28
  29 static inline void local_irq_disable(void)
  30 {
  31         unsigned long flags;
  32         __asm__ __volatile__ ("rsil %0, "__stringify(LOCKLEVEL)
  33                               : "=a" (flags) :: "memory");
  34 }
  35 static inline void local_irq_enable(void)
  36 {
  37         unsigned long flags;
  38         __asm__ __volatile__ ("rsil %0, 0" : "=a" (flags) :: "memory");
  39
  40 }
  41
  42 static inline int irqs_disabled(void)
  43 {
  44         unsigned long flags;
  45         local_save_flags(flags);
  46         return flags & 0xf;
  47 }
  48
  49 #define RSR_CPENABLE(x) do {                                              \
  50         __asm__ __volatile__("rsr %0," __stringify(CPENABLE) : "=a" (x)); \
  51         } while(0);
  52 #define WSR_CPENABLE(x) do {                                              \
  53         __asm__ __volatile__("wsr %0," __stringify(CPENABLE)";rsync"      \
  54                              :: "a" (x));} while(0);
  55
  56 #define clear_cpenable() __clear_cpenable()
  57
  58 static inline void __clear_cpenable(void)
  59 {
  60 #if XCHAL_HAVE_CP
  61         unsigned long i = 0;
  62         WSR_CPENABLE(i);
  63 #endif
  64 }
  65
  66 static inline void enable_coprocessor(int i)
  67 {
  68 #if XCHAL_HAVE_CP
  69         int cp;
  70         RSR_CPENABLE(cp);
  71         cp |= 1 << i;
  72         WSR_CPENABLE(cp);
  73 #endif
  74 }
  75
  76 static inline void disable_coprocessor(int i)
  77 {
  78 #if XCHAL_HAVE_CP
  79         int cp;
  80         RSR_CPENABLE(cp);
  81         cp &= ~(1 << i);
  82         WSR_CPENABLE(cp);
  83 #endif
  84 }
  85
  86 #define smp_read_barrier_depends() do { } while(0)
  87 #define read_barrier_depends() do { } while(0)
  88
  89 #define mb()  barrier()
  90 #define rmb() mb()
  91 #define wmb() mb()
  92
  93 #ifdef CONFIG_SMP
  94 #error smp_* not defined
  95 #else
  96 #define smp_mb()        barrier()
  97 #define smp_rmb()       barrier()
  98 #define smp_wmb()       barrier()
  99 #endif
 100
 101 #define set_mb(var, value)      do { var = value; mb(); } while (0)
 102 #define set_wmb(var, value)     do { var = value; wmb(); } while (0)
 103
 104 #if !defined (__ASSEMBLY__)
 105
 106 /* * switch_to(n) should switch tasks to task nr n, first
 107  * checking that n isn't the current task, in which case it does nothing.
 108  */
 109 extern void *_switch_to(void *last, void *next);
 110
 111 #endif  /* __ASSEMBLY__ */
 112
 113 #define switch_to(prev,next,last)               \
 114 do {                                            \
 115         clear_cpenable();                       \
 116         (last) = _switch_to(prev, next);        \
 117 } while(0)
 118
 119 /*
 120  * cmpxchg
 121  */
 122
 123 static inline unsigned long
 124 __cmpxchg_u32(volatile int *p, int old, int new)
 125 {
 126   __asm__ __volatile__("rsil    a15, "__stringify(LOCKLEVEL)"\n\t"
 127                        "l32i    %0, %1, 0              \n\t"
 128                        "bne     %0, %2, 1f             \n\t"
 129                        "s32i    %3, %1, 0              \n\t"
 130                        "1:                             \n\t"
 131                        "wsr     a15, "__stringify(PS)" \n\t"
 132                        "rsync                          \n\t"
 133                        : "=&a" (old)
 134                        : "a" (p), "a" (old), "r" (new)
 135                        : "a15", "memory");
 136   return old;
 137 }
 138 /* This function doesn't exist, so you'll get a linker error
 139  * if something tries to do an invalid cmpxchg(). */
 140
 141 extern void __cmpxchg_called_with_bad_pointer(void);
 142
 143 static __inline__ unsigned long
 144 __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, int size)
 145 {
 146         switch (size) {
 147         case 4:  return __cmpxchg_u32(ptr, old, new);
 148         default: __cmpxchg_called_with_bad_pointer();
 149                  return old;
 150         }
 151 }
 152
 153 #define cmpxchg(ptr,o,n)                                                      \
 154         ({ __typeof__(*(ptr)) _o_ = (o);                                      \
 155            __typeof__(*(ptr)) _n_ = (n);                                      \
 156            (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_,          \
 157                                         (unsigned long)_n_, sizeof (*(ptr))); \
 158         })
 159
 160
 161
 162
 163 /*
 164  * xchg_u32
 165  *
 166  * Note that a15 is used here because the register allocation
 167  * done by the compiler is not guaranteed and a window overflow
 168  * may not occur between the rsil and wsr instructions. By using
 169  * a15 in the rsil, the machine is guaranteed to be in a state
 170  * where no register reference will cause an overflow.
 171  */
 172
 173 static inline unsigned long xchg_u32(volatile int * m, unsigned long val)
 174 {
 175   unsigned long tmp;
 176   __asm__ __volatile__("rsil    a15, "__stringify(LOCKLEVEL)"\n\t"
 177                        "l32i    %0, %1, 0              \n\t"
 178                        "s32i    %2, %1, 0              \n\t"
 179                        "wsr     a15, "__stringify(PS)" \n\t"
 180                        "rsync                          \n\t"
 181                        : "=&a" (tmp)
 182                        : "a" (m), "a" (val)
 183                        : "a15", "memory");
 184   return tmp;
 185 }
 186
 187 #define tas(ptr) (xchg((ptr),1))
 188
 189 #define xchg(ptr,x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
 190
 191 /*
 192  * This only works if the compiler isn't horribly bad at optimizing.
 193  * gcc-2.5.8 reportedly can't handle this, but I define that one to
 194  * be dead anyway.
 195  */
 196
 197 extern void __xchg_called_with_bad_pointer(void);
 198
 199 static __inline__ unsigned long
 200 __xchg(unsigned long x, volatile void * ptr, int size)
 201 {
 202         switch (size) {
 203                 case 4:
 204                         return xchg_u32(ptr, x);
 205         }
 206         __xchg_called_with_bad_pointer();
 207         return x;
 208 }
 209
 210 extern void set_except_vector(int n, void *addr);
 211
 212 static inline void spill_registers(void)
 213 {
 214         unsigned int a0, ps;
 215
 216         __asm__ __volatile__ (
 217                 "movi   a14," __stringify (PS_EXCM_MASK) " | 1\n\t"
 218                 "mov    a12, a0\n\t"
 219                 "rsr    a13," __stringify(SAR) "\n\t"
 220                 "xsr    a14," __stringify(PS) "\n\t"
 221                 "movi   a0, _spill_registers\n\t"
 222                 "rsync\n\t"
 223                 "callx0 a0\n\t"
 224                 "mov    a0, a12\n\t"
 225                 "wsr    a13," __stringify(SAR) "\n\t"
 226                 "wsr    a14," __stringify(PS) "\n\t"
 227                 :: "a" (&a0), "a" (&ps)
 228                 : "a2", "a3", "a12", "a13", "a14", "a15", "memory");
 229 }
 230
 231 #define arch_align_stack(x) (x)
 232
 233 #endif  /* _XTENSA_SYSTEM_H */