arch/m32r/include/asm/spinlock.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _ASM_M32R_SPINLOCK_H
   3 #define _ASM_M32R_SPINLOCK_H
   4
   5 /*
   6  *  linux/include/asm-m32r/spinlock.h
   7  *
   8  *  M32R version:
   9  *    Copyright (C) 2001, 2002  Hitoshi Yamamoto
  10  *    Copyright (C) 2004  Hirokazu Takata <takata at linux-m32r.org>
  11  */
  12
  13 #include <linux/compiler.h>
  14 #include <linux/atomic.h>
  15 #include <asm/dcache_clear.h>
  16 #include <asm/page.h>
  17 #include <asm/barrier.h>
  18 #include <asm/processor.h>
  19
  20 /*
  21  * Your basic SMP spinlocks, allowing only a single CPU anywhere
  22  *
  23  * (the type definitions are in asm/spinlock_types.h)
  24  *
  25  * Simple spin lock operations.  There are two variants, one clears IRQ's
  26  * on the local processor, one does not.
  27  *
  28  * We make no fairness assumptions. They have a cost.
  29  */
  30
  31 #define arch_spin_is_locked(x)          (*(volatile int *)(&(x)->slock) <= 0)
  32 #define arch_spin_lock_flags(lock, flags) arch_spin_lock(lock)
  33
  34 /**
  35  * arch_spin_trylock - Try spin lock and return a result
  36  * @lock: Pointer to the lock variable
  37  *
  38  * arch_spin_trylock() tries to get the lock and returns a result.
  39  * On the m32r, the result value is 1 (= Success) or 0 (= Failure).
  40  */
  41 static inline int arch_spin_trylock(arch_spinlock_t *lock)
  42 {
  43         int oldval;
  44         unsigned long tmp1, tmp2;
  45
  46         /*
  47          * lock->slock :  =1 : unlock
  48          *             : <=0 : lock
  49          * {
  50          *   oldval = lock->slock; <--+ need atomic operation
  51          *   lock->slock = 0;      <--+
  52          * }
  53          */
  54         __asm__ __volatile__ (
  55                 "# arch_spin_trylock            \n\t"
  56                 "ldi    %1, #0;                 \n\t"
  57                 "mvfc   %2, psw;                \n\t"
  58                 "clrpsw #0x40 -> nop;           \n\t"
  59                 DCACHE_CLEAR("%0", "r6", "%3")
  60                 "lock   %0, @%3;                \n\t"
  61                 "unlock %1, @%3;                \n\t"
  62                 "mvtc   %2, psw;                \n\t"
  63                 : "=&r" (oldval), "=&r" (tmp1), "=&r" (tmp2)
  64                 : "r" (&lock->slock)
  65                 : "memory"
  66 #ifdef CONFIG_CHIP_M32700_TS1
  67                 , "r6"
  68 #endif  /* CONFIG_CHIP_M32700_TS1 */
  69         );
  70
  71         return (oldval > 0);
  72 }
  73
  74 static inline void arch_spin_lock(arch_spinlock_t *lock)
  75 {
  76         unsigned long tmp0, tmp1;
  77
  78         /*
  79          * lock->slock :  =1 : unlock
  80          *             : <=0 : lock
  81          *
  82          * for ( ; ; ) {
  83          *   lock->slock -= 1;  <-- need atomic operation
  84          *   if (lock->slock == 0) break;
  85          *   for ( ; lock->slock <= 0 ; );
  86          * }
  87          */
  88         __asm__ __volatile__ (
  89                 "# arch_spin_lock               \n\t"
  90                 ".fillinsn                      \n"
  91                 "1:                             \n\t"
  92                 "mvfc   %1, psw;                \n\t"
  93                 "clrpsw #0x40 -> nop;           \n\t"
  94                 DCACHE_CLEAR("%0", "r6", "%2")
  95                 "lock   %0, @%2;                \n\t"
  96                 "addi   %0, #-1;                \n\t"
  97                 "unlock %0, @%2;                \n\t"
  98                 "mvtc   %1, psw;                \n\t"
  99                 "bltz   %0, 2f;                 \n\t"
 100                 LOCK_SECTION_START(".balign 4 \n\t")
 101                 ".fillinsn                      \n"
 102                 "2:                             \n\t"
 103                 "ld     %0, @%2;                \n\t"
 104                 "bgtz   %0, 1b;                 \n\t"
 105                 "bra    2b;                     \n\t"
 106                 LOCK_SECTION_END
 107                 : "=&r" (tmp0), "=&r" (tmp1)
 108                 : "r" (&lock->slock)
 109                 : "memory"
 110 #ifdef CONFIG_CHIP_M32700_TS1
 111                 , "r6"
 112 #endif  /* CONFIG_CHIP_M32700_TS1 */
 113         );
 114 }
 115
 116 static inline void arch_spin_unlock(arch_spinlock_t *lock)
 117 {
 118         mb();
 119         lock->slock = 1;
 120 }
 121
 122 /*
 123  * Read-write spinlocks, allowing multiple readers
 124  * but only one writer.
 125  *
 126  * NOTE! it is quite common to have readers in interrupts
 127  * but no interrupt writers. For those circumstances we
 128  * can "mix" irq-safe locks - any writer needs to get a
 129  * irq-safe write-lock, but readers can get non-irqsafe
 130  * read-locks.
 131  *
 132  * On x86, we implement read-write locks as a 32-bit counter
 133  * with the high bit (sign) being the "contended" bit.
 134  *
 135  * The inline assembly is non-obvious. Think about it.
 136  *
 137  * Changed to use the same technique as rw semaphores.  See
 138  * semaphore.h for details.  -ben
 139  */
 140
 141 /**
 142  * read_can_lock - would read_trylock() succeed?
 143  * @lock: the rwlock in question.
 144  */
 145 #define arch_read_can_lock(x) ((int)(x)->lock > 0)
 146
 147 /**
 148  * write_can_lock - would write_trylock() succeed?
 149  * @lock: the rwlock in question.
 150  */
 151 #define arch_write_can_lock(x) ((x)->lock == RW_LOCK_BIAS)
 152
 153 static inline void arch_read_lock(arch_rwlock_t *rw)
 154 {
 155         unsigned long tmp0, tmp1;
 156
 157         /*
 158          * rw->lock :  >0 : unlock
 159          *          : <=0 : lock
 160          *
 161          * for ( ; ; ) {
 162          *   rw->lock -= 1;  <-- need atomic operation
 163          *   if (rw->lock >= 0) break;
 164          *   rw->lock += 1;  <-- need atomic operation
 165          *   for ( ; rw->lock <= 0 ; );
 166          * }
 167          */
 168         __asm__ __volatile__ (
 169                 "# read_lock                    \n\t"
 170                 ".fillinsn                      \n"
 171                 "1:                             \n\t"
 172                 "mvfc   %1, psw;                \n\t"
 173                 "clrpsw #0x40 -> nop;           \n\t"
 174                 DCACHE_CLEAR("%0", "r6", "%2")
 175                 "lock   %0, @%2;                \n\t"
 176                 "addi   %0, #-1;                \n\t"
 177                 "unlock %0, @%2;                \n\t"
 178                 "mvtc   %1, psw;                \n\t"
 179                 "bltz   %0, 2f;                 \n\t"
 180                 LOCK_SECTION_START(".balign 4 \n\t")
 181                 ".fillinsn                      \n"
 182                 "2:                             \n\t"
 183                 "clrpsw #0x40 -> nop;           \n\t"
 184                 DCACHE_CLEAR("%0", "r6", "%2")
 185                 "lock   %0, @%2;                \n\t"
 186                 "addi   %0, #1;                 \n\t"
 187                 "unlock %0, @%2;                \n\t"
 188                 "mvtc   %1, psw;                \n\t"
 189                 ".fillinsn                      \n"
 190                 "3:                             \n\t"
 191                 "ld     %0, @%2;                \n\t"
 192                 "bgtz   %0, 1b;                 \n\t"
 193                 "bra    3b;                     \n\t"
 194                 LOCK_SECTION_END
 195                 : "=&r" (tmp0), "=&r" (tmp1)
 196                 : "r" (&rw->lock)
 197                 : "memory"
 198 #ifdef CONFIG_CHIP_M32700_TS1
 199                 , "r6"
 200 #endif  /* CONFIG_CHIP_M32700_TS1 */
 201         );
 202 }
 203
 204 static inline void arch_write_lock(arch_rwlock_t *rw)
 205 {
 206         unsigned long tmp0, tmp1, tmp2;
 207
 208         /*
 209          * rw->lock :  =RW_LOCK_BIAS_STR : unlock
 210          *          : !=RW_LOCK_BIAS_STR : lock
 211          *
 212          * for ( ; ; ) {
 213          *   rw->lock -= RW_LOCK_BIAS_STR;  <-- need atomic operation
 214          *   if (rw->lock == 0) break;
 215          *   rw->lock += RW_LOCK_BIAS_STR;  <-- need atomic operation
 216          *   for ( ; rw->lock != RW_LOCK_BIAS_STR ; ) ;
 217          * }
 218          */
 219         __asm__ __volatile__ (
 220                 "# write_lock                                   \n\t"
 221                 "seth   %1, #high(" RW_LOCK_BIAS_STR ");        \n\t"
 222                 "or3    %1, %1, #low(" RW_LOCK_BIAS_STR ");     \n\t"
 223                 ".fillinsn                                      \n"
 224                 "1:                                             \n\t"
 225                 "mvfc   %2, psw;                                \n\t"
 226                 "clrpsw #0x40 -> nop;                           \n\t"
 227                 DCACHE_CLEAR("%0", "r7", "%3")
 228                 "lock   %0, @%3;                                \n\t"
 229                 "sub    %0, %1;                                 \n\t"
 230                 "unlock %0, @%3;                                \n\t"
 231                 "mvtc   %2, psw;                                \n\t"
 232                 "bnez   %0, 2f;                                 \n\t"
 233                 LOCK_SECTION_START(".balign 4 \n\t")
 234                 ".fillinsn                                      \n"
 235                 "2:                                             \n\t"
 236                 "clrpsw #0x40 -> nop;                           \n\t"
 237                 DCACHE_CLEAR("%0", "r7", "%3")
 238                 "lock   %0, @%3;                                \n\t"
 239                 "add    %0, %1;                                 \n\t"
 240                 "unlock %0, @%3;                                \n\t"
 241                 "mvtc   %2, psw;                                \n\t"
 242                 ".fillinsn                                      \n"
 243                 "3:                                             \n\t"
 244                 "ld     %0, @%3;                                \n\t"
 245                 "beq    %0, %1, 1b;                             \n\t"
 246                 "bra    3b;                                     \n\t"
 247                 LOCK_SECTION_END
 248                 : "=&r" (tmp0), "=&r" (tmp1), "=&r" (tmp2)
 249                 : "r" (&rw->lock)
 250                 : "memory"
 251 #ifdef CONFIG_CHIP_M32700_TS1
 252                 , "r7"
 253 #endif  /* CONFIG_CHIP_M32700_TS1 */
 254         );
 255 }
 256
 257 static inline void arch_read_unlock(arch_rwlock_t *rw)
 258 {
 259         unsigned long tmp0, tmp1;
 260
 261         __asm__ __volatile__ (
 262                 "# read_unlock                  \n\t"
 263                 "mvfc   %1, psw;                \n\t"
 264                 "clrpsw #0x40 -> nop;           \n\t"
 265                 DCACHE_CLEAR("%0", "r6", "%2")
 266                 "lock   %0, @%2;                \n\t"
 267                 "addi   %0, #1;                 \n\t"
 268                 "unlock %0, @%2;                \n\t"
 269                 "mvtc   %1, psw;                \n\t"
 270                 : "=&r" (tmp0), "=&r" (tmp1)
 271                 : "r" (&rw->lock)
 272                 : "memory"
 273 #ifdef CONFIG_CHIP_M32700_TS1
 274                 , "r6"
 275 #endif  /* CONFIG_CHIP_M32700_TS1 */
 276         );
 277 }
 278
 279 static inline void arch_write_unlock(arch_rwlock_t *rw)
 280 {
 281         unsigned long tmp0, tmp1, tmp2;
 282
 283         __asm__ __volatile__ (
 284                 "# write_unlock                                 \n\t"
 285                 "seth   %1, #high(" RW_LOCK_BIAS_STR ");        \n\t"
 286                 "or3    %1, %1, #low(" RW_LOCK_BIAS_STR ");     \n\t"
 287                 "mvfc   %2, psw;                                \n\t"
 288                 "clrpsw #0x40 -> nop;                           \n\t"
 289                 DCACHE_CLEAR("%0", "r7", "%3")
 290                 "lock   %0, @%3;                                \n\t"
 291                 "add    %0, %1;                                 \n\t"
 292                 "unlock %0, @%3;                                \n\t"
 293                 "mvtc   %2, psw;                                \n\t"
 294                 : "=&r" (tmp0), "=&r" (tmp1), "=&r" (tmp2)
 295                 : "r" (&rw->lock)
 296                 : "memory"
 297 #ifdef CONFIG_CHIP_M32700_TS1
 298                 , "r7"
 299 #endif  /* CONFIG_CHIP_M32700_TS1 */
 300         );
 301 }
 302
 303 static inline int arch_read_trylock(arch_rwlock_t *lock)
 304 {
 305         atomic_t *count = (atomic_t*)lock;
 306         if (atomic_dec_return(count) >= 0)
 307                 return 1;
 308         atomic_inc(count);
 309         return 0;
 310 }
 311
 312 static inline int arch_write_trylock(arch_rwlock_t *lock)
 313 {
 314         atomic_t *count = (atomic_t *)lock;
 315         if (atomic_sub_and_test(RW_LOCK_BIAS, count))
 316                 return 1;
 317         atomic_add(RW_LOCK_BIAS, count);
 318         return 0;
 319 }
 320
 321 #define arch_read_lock_flags(lock, flags) arch_read_lock(lock)
 322 #define arch_write_lock_flags(lock, flags) arch_write_lock(lock)
 323
 324 #define arch_spin_relax(lock)   cpu_relax()
 325 #define arch_read_relax(lock)   cpu_relax()
 326 #define arch_write_relax(lock)  cpu_relax()
 327
 328 #endif  /* _ASM_M32R_SPINLOCK_H */