arch/m32r/include/asm/spinlock.h

   1 #ifndef _ASM_M32R_SPINLOCK_H
   2 #define _ASM_M32R_SPINLOCK_H
   3
   4 /*
   5  *  linux/include/asm-m32r/spinlock.h
   6  *
   7  *  M32R version:
   8  *    Copyright (C) 2001, 2002  Hitoshi Yamamoto
   9  *    Copyright (C) 2004  Hirokazu Takata <takata at linux-m32r.org>
  10  */
  11
  12 #include <linux/compiler.h>
  13 #include <linux/atomic.h>
  14 #include <asm/page.h>
  15
  16 /*
  17  * Your basic SMP spinlocks, allowing only a single CPU anywhere
  18  *
  19  * (the type definitions are in asm/spinlock_types.h)
  20  *
  21  * Simple spin lock operations.  There are two variants, one clears IRQ's
  22  * on the local processor, one does not.
  23  *
  24  * We make no fairness assumptions. They have a cost.
  25  */
  26
  27 #define arch_spin_is_locked(x)          (*(volatile int *)(&(x)->slock) <= 0)
  28 #define arch_spin_lock_flags(lock, flags) arch_spin_lock(lock)
  29 #define arch_spin_unlock_wait(x) \
  30                 do { cpu_relax(); } while (arch_spin_is_locked(x))
  31
  32 /**
  33  * arch_spin_trylock - Try spin lock and return a result
  34  * @lock: Pointer to the lock variable
  35  *
  36  * arch_spin_trylock() tries to get the lock and returns a result.
  37  * On the m32r, the result value is 1 (= Success) or 0 (= Failure).
  38  */
  39 static inline int arch_spin_trylock(arch_spinlock_t *lock)
  40 {
  41         int oldval;
  42         unsigned long tmp1, tmp2;
  43
  44         /*
  45          * lock->slock :  =1 : unlock
  46          *             : <=0 : lock
  47          * {
  48          *   oldval = lock->slock; <--+ need atomic operation
  49          *   lock->slock = 0;      <--+
  50          * }
  51          */
  52         __asm__ __volatile__ (
  53                 "# arch_spin_trylock            \n\t"
  54                 "ldi    %1, #0;                 \n\t"
  55                 "mvfc   %2, psw;                \n\t"
  56                 "clrpsw #0x40 -> nop;           \n\t"
  57                 DCACHE_CLEAR("%0", "r6", "%3")
  58                 "lock   %0, @%3;                \n\t"
  59                 "unlock %1, @%3;                \n\t"
  60                 "mvtc   %2, psw;                \n\t"
  61                 : "=&r" (oldval), "=&r" (tmp1), "=&r" (tmp2)
  62                 : "r" (&lock->slock)
  63                 : "memory"
  64 #ifdef CONFIG_CHIP_M32700_TS1
  65                 , "r6"
  66 #endif  /* CONFIG_CHIP_M32700_TS1 */
  67         );
  68
  69         return (oldval > 0);
  70 }
  71
  72 static inline void arch_spin_lock(arch_spinlock_t *lock)
  73 {
  74         unsigned long tmp0, tmp1;
  75
  76         /*
  77          * lock->slock :  =1 : unlock
  78          *             : <=0 : lock
  79          *
  80          * for ( ; ; ) {
  81          *   lock->slock -= 1;  <-- need atomic operation
  82          *   if (lock->slock == 0) break;
  83          *   for ( ; lock->slock <= 0 ; );
  84          * }
  85          */
  86         __asm__ __volatile__ (
  87                 "# arch_spin_lock               \n\t"
  88                 ".fillinsn                      \n"
  89                 "1:                             \n\t"
  90                 "mvfc   %1, psw;                \n\t"
  91                 "clrpsw #0x40 -> nop;           \n\t"
  92                 DCACHE_CLEAR("%0", "r6", "%2")
  93                 "lock   %0, @%2;                \n\t"
  94                 "addi   %0, #-1;                \n\t"
  95                 "unlock %0, @%2;                \n\t"
  96                 "mvtc   %1, psw;                \n\t"
  97                 "bltz   %0, 2f;                 \n\t"
  98                 LOCK_SECTION_START(".balign 4 \n\t")
  99                 ".fillinsn                      \n"
 100                 "2:                             \n\t"
 101                 "ld     %0, @%2;                \n\t"
 102                 "bgtz   %0, 1b;                 \n\t"
 103                 "bra    2b;                     \n\t"
 104                 LOCK_SECTION_END
 105                 : "=&r" (tmp0), "=&r" (tmp1)
 106                 : "r" (&lock->slock)
 107                 : "memory"
 108 #ifdef CONFIG_CHIP_M32700_TS1
 109                 , "r6"
 110 #endif  /* CONFIG_CHIP_M32700_TS1 */
 111         );
 112 }
 113
 114 static inline void arch_spin_unlock(arch_spinlock_t *lock)
 115 {
 116         mb();
 117         lock->slock = 1;
 118 }
 119
 120 /*
 121  * Read-write spinlocks, allowing multiple readers
 122  * but only one writer.
 123  *
 124  * NOTE! it is quite common to have readers in interrupts
 125  * but no interrupt writers. For those circumstances we
 126  * can "mix" irq-safe locks - any writer needs to get a
 127  * irq-safe write-lock, but readers can get non-irqsafe
 128  * read-locks.
 129  *
 130  * On x86, we implement read-write locks as a 32-bit counter
 131  * with the high bit (sign) being the "contended" bit.
 132  *
 133  * The inline assembly is non-obvious. Think about it.
 134  *
 135  * Changed to use the same technique as rw semaphores.  See
 136  * semaphore.h for details.  -ben
 137  */
 138
 139 /**
 140  * read_can_lock - would read_trylock() succeed?
 141  * @lock: the rwlock in question.
 142  */
 143 #define arch_read_can_lock(x) ((int)(x)->lock > 0)
 144
 145 /**
 146  * write_can_lock - would write_trylock() succeed?
 147  * @lock: the rwlock in question.
 148  */
 149 #define arch_write_can_lock(x) ((x)->lock == RW_LOCK_BIAS)
 150
 151 static inline void arch_read_lock(arch_rwlock_t *rw)
 152 {
 153         unsigned long tmp0, tmp1;
 154
 155         /*
 156          * rw->lock :  >0 : unlock
 157          *          : <=0 : lock
 158          *
 159          * for ( ; ; ) {
 160          *   rw->lock -= 1;  <-- need atomic operation
 161          *   if (rw->lock >= 0) break;
 162          *   rw->lock += 1;  <-- need atomic operation
 163          *   for ( ; rw->lock <= 0 ; );
 164          * }
 165          */
 166         __asm__ __volatile__ (
 167                 "# read_lock                    \n\t"
 168                 ".fillinsn                      \n"
 169                 "1:                             \n\t"
 170                 "mvfc   %1, psw;                \n\t"
 171                 "clrpsw #0x40 -> nop;           \n\t"
 172                 DCACHE_CLEAR("%0", "r6", "%2")
 173                 "lock   %0, @%2;                \n\t"
 174                 "addi   %0, #-1;                \n\t"
 175                 "unlock %0, @%2;                \n\t"
 176                 "mvtc   %1, psw;                \n\t"
 177                 "bltz   %0, 2f;                 \n\t"
 178                 LOCK_SECTION_START(".balign 4 \n\t")
 179                 ".fillinsn                      \n"
 180                 "2:                             \n\t"
 181                 "clrpsw #0x40 -> nop;           \n\t"
 182                 DCACHE_CLEAR("%0", "r6", "%2")
 183                 "lock   %0, @%2;                \n\t"
 184                 "addi   %0, #1;                 \n\t"
 185                 "unlock %0, @%2;                \n\t"
 186                 "mvtc   %1, psw;                \n\t"
 187                 ".fillinsn                      \n"
 188                 "3:                             \n\t"
 189                 "ld     %0, @%2;                \n\t"
 190                 "bgtz   %0, 1b;                 \n\t"
 191                 "bra    3b;                     \n\t"
 192                 LOCK_SECTION_END
 193                 : "=&r" (tmp0), "=&r" (tmp1)
 194                 : "r" (&rw->lock)
 195                 : "memory"
 196 #ifdef CONFIG_CHIP_M32700_TS1
 197                 , "r6"
 198 #endif  /* CONFIG_CHIP_M32700_TS1 */
 199         );
 200 }
 201
 202 static inline void arch_write_lock(arch_rwlock_t *rw)
 203 {
 204         unsigned long tmp0, tmp1, tmp2;
 205
 206         /*
 207          * rw->lock :  =RW_LOCK_BIAS_STR : unlock
 208          *          : !=RW_LOCK_BIAS_STR : lock
 209          *
 210          * for ( ; ; ) {
 211          *   rw->lock -= RW_LOCK_BIAS_STR;  <-- need atomic operation
 212          *   if (rw->lock == 0) break;
 213          *   rw->lock += RW_LOCK_BIAS_STR;  <-- need atomic operation
 214          *   for ( ; rw->lock != RW_LOCK_BIAS_STR ; ) ;
 215          * }
 216          */
 217         __asm__ __volatile__ (
 218                 "# write_lock                                   \n\t"
 219                 "seth   %1, #high(" RW_LOCK_BIAS_STR ");        \n\t"
 220                 "or3    %1, %1, #low(" RW_LOCK_BIAS_STR ");     \n\t"
 221                 ".fillinsn                                      \n"
 222                 "1:                                             \n\t"
 223                 "mvfc   %2, psw;                                \n\t"
 224                 "clrpsw #0x40 -> nop;                           \n\t"
 225                 DCACHE_CLEAR("%0", "r7", "%3")
 226                 "lock   %0, @%3;                                \n\t"
 227                 "sub    %0, %1;                                 \n\t"
 228                 "unlock %0, @%3;                                \n\t"
 229                 "mvtc   %2, psw;                                \n\t"
 230                 "bnez   %0, 2f;                                 \n\t"
 231                 LOCK_SECTION_START(".balign 4 \n\t")
 232                 ".fillinsn                                      \n"
 233                 "2:                                             \n\t"
 234                 "clrpsw #0x40 -> nop;                           \n\t"
 235                 DCACHE_CLEAR("%0", "r7", "%3")
 236                 "lock   %0, @%3;                                \n\t"
 237                 "add    %0, %1;                                 \n\t"
 238                 "unlock %0, @%3;                                \n\t"
 239                 "mvtc   %2, psw;                                \n\t"
 240                 ".fillinsn                                      \n"
 241                 "3:                                             \n\t"
 242                 "ld     %0, @%3;                                \n\t"
 243                 "beq    %0, %1, 1b;                             \n\t"
 244                 "bra    3b;                                     \n\t"
 245                 LOCK_SECTION_END
 246                 : "=&r" (tmp0), "=&r" (tmp1), "=&r" (tmp2)
 247                 : "r" (&rw->lock)
 248                 : "memory"
 249 #ifdef CONFIG_CHIP_M32700_TS1
 250                 , "r7"
 251 #endif  /* CONFIG_CHIP_M32700_TS1 */
 252         );
 253 }
 254
 255 static inline void arch_read_unlock(arch_rwlock_t *rw)
 256 {
 257         unsigned long tmp0, tmp1;
 258
 259         __asm__ __volatile__ (
 260                 "# read_unlock                  \n\t"
 261                 "mvfc   %1, psw;                \n\t"
 262                 "clrpsw #0x40 -> nop;           \n\t"
 263                 DCACHE_CLEAR("%0", "r6", "%2")
 264                 "lock   %0, @%2;                \n\t"
 265                 "addi   %0, #1;                 \n\t"
 266                 "unlock %0, @%2;                \n\t"
 267                 "mvtc   %1, psw;                \n\t"
 268                 : "=&r" (tmp0), "=&r" (tmp1)
 269                 : "r" (&rw->lock)
 270                 : "memory"
 271 #ifdef CONFIG_CHIP_M32700_TS1
 272                 , "r6"
 273 #endif  /* CONFIG_CHIP_M32700_TS1 */
 274         );
 275 }
 276
 277 static inline void arch_write_unlock(arch_rwlock_t *rw)
 278 {
 279         unsigned long tmp0, tmp1, tmp2;
 280
 281         __asm__ __volatile__ (
 282                 "# write_unlock                                 \n\t"
 283                 "seth   %1, #high(" RW_LOCK_BIAS_STR ");        \n\t"
 284                 "or3    %1, %1, #low(" RW_LOCK_BIAS_STR ");     \n\t"
 285                 "mvfc   %2, psw;                                \n\t"
 286                 "clrpsw #0x40 -> nop;                           \n\t"
 287                 DCACHE_CLEAR("%0", "r7", "%3")
 288                 "lock   %0, @%3;                                \n\t"
 289                 "add    %0, %1;                                 \n\t"
 290                 "unlock %0, @%3;                                \n\t"
 291                 "mvtc   %2, psw;                                \n\t"
 292                 : "=&r" (tmp0), "=&r" (tmp1), "=&r" (tmp2)
 293                 : "r" (&rw->lock)
 294                 : "memory"
 295 #ifdef CONFIG_CHIP_M32700_TS1
 296                 , "r7"
 297 #endif  /* CONFIG_CHIP_M32700_TS1 */
 298         );
 299 }
 300
 301 static inline int arch_read_trylock(arch_rwlock_t *lock)
 302 {
 303         atomic_t *count = (atomic_t*)lock;
 304         if (atomic_dec_return(count) >= 0)
 305                 return 1;
 306         atomic_inc(count);
 307         return 0;
 308 }
 309
 310 static inline int arch_write_trylock(arch_rwlock_t *lock)
 311 {
 312         atomic_t *count = (atomic_t *)lock;
 313         if (atomic_sub_and_test(RW_LOCK_BIAS, count))
 314                 return 1;
 315         atomic_add(RW_LOCK_BIAS, count);
 316         return 0;
 317 }
 318
 319 #define arch_read_lock_flags(lock, flags) arch_read_lock(lock)
 320 #define arch_write_lock_flags(lock, flags) arch_write_lock(lock)
 321
 322 #define arch_spin_relax(lock)   cpu_relax()
 323 #define arch_read_relax(lock)   cpu_relax()
 324 #define arch_write_relax(lock)  cpu_relax()
 325
 326 #endif  /* _ASM_M32R_SPINLOCK_H */