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   1 /*
   2  * Atomic operations that C can't guarantee us.  Useful for
   3  * resource counting etc..
   4  *
   5  * But use these as seldom as possible since they are much more slower
   6  * than regular operations.
   7  *
   8  * This file is subject to the terms and conditions of the GNU General Public
   9  * License.  See the file "COPYING" in the main directory of this archive
  10  * for more details.
  11  *
  12  * Copyright (C) 1996, 97, 99, 2000, 03, 04, 06 by Ralf Baechle
  13  */
  14 #ifndef _ASM_ATOMIC_H
  15 #define _ASM_ATOMIC_H
  16
  17 #include <linux/irqflags.h>
  18 #include <asm/barrier.h>
  19 #include <asm/cpu-features.h>
  20 #include <asm/war.h>
  21 #include <asm/system.h>
  22
  23 typedef struct { volatile int counter; } atomic_t;
  24
  25 #define ATOMIC_INIT(i)    { (i) }
  26
  27 /*
  28  * atomic_read - read atomic variable
  29  * @v: pointer of type atomic_t
  30  *
  31  * Atomically reads the value of @v.
  32  */
  33 #define atomic_read(v)          ((v)->counter)
  34
  35 /*
  36  * atomic_set - set atomic variable
  37  * @v: pointer of type atomic_t
  38  * @i: required value
  39  *
  40  * Atomically sets the value of @v to @i.
  41  */
  42 #define atomic_set(v, i)                ((v)->counter = (i))
  43
  44 /*
  45  * atomic_add - add integer to atomic variable
  46  * @i: integer value to add
  47  * @v: pointer of type atomic_t
  48  *
  49  * Atomically adds @i to @v.
  50  */
  51 static __inline__ void atomic_add(int i, atomic_t * v)
  52 {
  53         if (cpu_has_llsc && R10000_LLSC_WAR) {
  54                 unsigned long temp;
  55
  56                 __asm__ __volatile__(
  57                 "       .set    mips3                                   \n"
  58                 "1:     ll      %0, %1          # atomic_add            \n"
  59                 "       addu    %0, %2                                  \n"
  60                 "       sc      %0, %1                                  \n"
  61                 "       beqzl   %0, 1b                                  \n"
  62                 "       .set    mips0                                   \n"
  63                 : "=&r" (temp), "=m" (v->counter)
  64                 : "Ir" (i), "m" (v->counter));
  65         } else if (cpu_has_llsc) {
  66                 unsigned long temp;
  67
  68                 __asm__ __volatile__(
  69                 "       .set    mips3                                   \n"
  70                 "1:     ll      %0, %1          # atomic_add            \n"
  71                 "       addu    %0, %2                                  \n"
  72                 "       sc      %0, %1                                  \n"
  73                 "       beqz    %0, 2f                                  \n"
  74                 "       .subsection 2                                   \n"
  75                 "2:     b       1b                                      \n"
  76                 "       .previous                                       \n"
  77                 "       .set    mips0                                   \n"
  78                 : "=&r" (temp), "=m" (v->counter)
  79                 : "Ir" (i), "m" (v->counter));
  80         } else {
  81                 unsigned long flags;
  82
  83                 raw_local_irq_save(flags);
  84                 v->counter += i;
  85                 raw_local_irq_restore(flags);
  86         }
  87 }
  88
  89 /*
  90  * atomic_sub - subtract the atomic variable
  91  * @i: integer value to subtract
  92  * @v: pointer of type atomic_t
  93  *
  94  * Atomically subtracts @i from @v.
  95  */
  96 static __inline__ void atomic_sub(int i, atomic_t * v)
  97 {
  98         if (cpu_has_llsc && R10000_LLSC_WAR) {
  99                 unsigned long temp;
 100
 101                 __asm__ __volatile__(
 102                 "       .set    mips3                                   \n"
 103                 "1:     ll      %0, %1          # atomic_sub            \n"
 104                 "       subu    %0, %2                                  \n"
 105                 "       sc      %0, %1                                  \n"
 106                 "       beqzl   %0, 1b                                  \n"
 107                 "       .set    mips0                                   \n"
 108                 : "=&r" (temp), "=m" (v->counter)
 109                 : "Ir" (i), "m" (v->counter));
 110         } else if (cpu_has_llsc) {
 111                 unsigned long temp;
 112
 113                 __asm__ __volatile__(
 114                 "       .set    mips3                                   \n"
 115                 "1:     ll      %0, %1          # atomic_sub            \n"
 116                 "       subu    %0, %2                                  \n"
 117                 "       sc      %0, %1                                  \n"
 118                 "       beqz    %0, 2f                                  \n"
 119                 "       .subsection 2                                   \n"
 120                 "2:     b       1b                                      \n"
 121                 "       .previous                                       \n"
 122                 "       .set    mips0                                   \n"
 123                 : "=&r" (temp), "=m" (v->counter)
 124                 : "Ir" (i), "m" (v->counter));
 125         } else {
 126                 unsigned long flags;
 127
 128                 raw_local_irq_save(flags);
 129                 v->counter -= i;
 130                 raw_local_irq_restore(flags);
 131         }
 132 }
 133
 134 /*
 135  * Same as above, but return the result value
 136  */
 137 static __inline__ int atomic_add_return(int i, atomic_t * v)
 138 {
 139         unsigned long result;
 140
 141         smp_llsc_mb();
 142
 143         if (cpu_has_llsc && R10000_LLSC_WAR) {
 144                 unsigned long temp;
 145
 146                 __asm__ __volatile__(
 147                 "       .set    mips3                                   \n"
 148                 "1:     ll      %1, %2          # atomic_add_return     \n"
 149                 "       addu    %0, %1, %3                              \n"
 150                 "       sc      %0, %2                                  \n"
 151                 "       beqzl   %0, 1b                                  \n"
 152                 "       addu    %0, %1, %3                              \n"
 153                 "       .set    mips0                                   \n"
 154                 : "=&r" (result), "=&r" (temp), "=m" (v->counter)
 155                 : "Ir" (i), "m" (v->counter)
 156                 : "memory");
 157         } else if (cpu_has_llsc) {
 158                 unsigned long temp;
 159
 160                 __asm__ __volatile__(
 161                 "       .set    mips3                                   \n"
 162                 "1:     ll      %1, %2          # atomic_add_return     \n"
 163                 "       addu    %0, %1, %3                              \n"
 164                 "       sc      %0, %2                                  \n"
 165                 "       beqz    %0, 2f                                  \n"
 166                 "       addu    %0, %1, %3                              \n"
 167                 "       .subsection 2                                   \n"
 168                 "2:     b       1b                                      \n"
 169                 "       .previous                                       \n"
 170                 "       .set    mips0                                   \n"
 171                 : "=&r" (result), "=&r" (temp), "=m" (v->counter)
 172                 : "Ir" (i), "m" (v->counter)
 173                 : "memory");
 174         } else {
 175                 unsigned long flags;
 176
 177                 raw_local_irq_save(flags);
 178                 result = v->counter;
 179                 result += i;
 180                 v->counter = result;
 181                 raw_local_irq_restore(flags);
 182         }
 183
 184         smp_llsc_mb();
 185
 186         return result;
 187 }
 188
 189 static __inline__ int atomic_sub_return(int i, atomic_t * v)
 190 {
 191         unsigned long result;
 192
 193         smp_llsc_mb();
 194
 195         if (cpu_has_llsc && R10000_LLSC_WAR) {
 196                 unsigned long temp;
 197
 198                 __asm__ __volatile__(
 199                 "       .set    mips3                                   \n"
 200                 "1:     ll      %1, %2          # atomic_sub_return     \n"
 201                 "       subu    %0, %1, %3                              \n"
 202                 "       sc      %0, %2                                  \n"
 203                 "       beqzl   %0, 1b                                  \n"
 204                 "       subu    %0, %1, %3                              \n"
 205                 "       .set    mips0                                   \n"
 206                 : "=&r" (result), "=&r" (temp), "=m" (v->counter)
 207                 : "Ir" (i), "m" (v->counter)
 208                 : "memory");
 209         } else if (cpu_has_llsc) {
 210                 unsigned long temp;
 211
 212                 __asm__ __volatile__(
 213                 "       .set    mips3                                   \n"
 214                 "1:     ll      %1, %2          # atomic_sub_return     \n"
 215                 "       subu    %0, %1, %3                              \n"
 216                 "       sc      %0, %2                                  \n"
 217                 "       beqz    %0, 2f                                  \n"
 218                 "       subu    %0, %1, %3                              \n"
 219                 "       .subsection 2                                   \n"
 220                 "2:     b       1b                                      \n"
 221                 "       .previous                                       \n"
 222                 "       .set    mips0                                   \n"
 223                 : "=&r" (result), "=&r" (temp), "=m" (v->counter)
 224                 : "Ir" (i), "m" (v->counter)
 225                 : "memory");
 226         } else {
 227                 unsigned long flags;
 228
 229                 raw_local_irq_save(flags);
 230                 result = v->counter;
 231                 result -= i;
 232                 v->counter = result;
 233                 raw_local_irq_restore(flags);
 234         }
 235
 236         smp_llsc_mb();
 237
 238         return result;
 239 }
 240
 241 /*
 242  * atomic_sub_if_positive - conditionally subtract integer from atomic variable
 243  * @i: integer value to subtract
 244  * @v: pointer of type atomic_t
 245  *
 246  * Atomically test @v and subtract @i if @v is greater or equal than @i.
 247  * The function returns the old value of @v minus @i.
 248  */
 249 static __inline__ int atomic_sub_if_positive(int i, atomic_t * v)
 250 {
 251         unsigned long result;
 252
 253         smp_llsc_mb();
 254
 255         if (cpu_has_llsc && R10000_LLSC_WAR) {
 256                 unsigned long temp;
 257
 258                 __asm__ __volatile__(
 259                 "       .set    mips3                                   \n"
 260                 "1:     ll      %1, %2          # atomic_sub_if_positive\n"
 261                 "       subu    %0, %1, %3                              \n"
 262                 "       bltz    %0, 1f                                  \n"
 263                 "       sc      %0, %2                                  \n"
 264                 "       .set    noreorder                               \n"
 265                 "       beqzl   %0, 1b                                  \n"
 266                 "        subu   %0, %1, %3                              \n"
 267                 "       .set    reorder                                 \n"
 268                 "1:                                                     \n"
 269                 "       .set    mips0                                   \n"
 270                 : "=&r" (result), "=&r" (temp), "=m" (v->counter)
 271                 : "Ir" (i), "m" (v->counter)
 272                 : "memory");
 273         } else if (cpu_has_llsc) {
 274                 unsigned long temp;
 275
 276                 __asm__ __volatile__(
 277                 "       .set    mips3                                   \n"
 278                 "1:     ll      %1, %2          # atomic_sub_if_positive\n"
 279                 "       subu    %0, %1, %3                              \n"
 280                 "       bltz    %0, 1f                                  \n"
 281                 "       sc      %0, %2                                  \n"
 282                 "       .set    noreorder                               \n"
 283                 "       beqz    %0, 2f                                  \n"
 284                 "        subu   %0, %1, %3                              \n"
 285                 "       .set    reorder                                 \n"
 286                 "1:                                                     \n"
 287                 "       .subsection 2                                   \n"
 288                 "2:     b       1b                                      \n"
 289                 "       .previous                                       \n"
 290                 "       .set    mips0                                   \n"
 291                 : "=&r" (result), "=&r" (temp), "=m" (v->counter)
 292                 : "Ir" (i), "m" (v->counter)
 293                 : "memory");
 294         } else {
 295                 unsigned long flags;
 296
 297                 raw_local_irq_save(flags);
 298                 result = v->counter;
 299                 result -= i;
 300                 if (result >= 0)
 301                         v->counter = result;
 302                 raw_local_irq_restore(flags);
 303         }
 304
 305         smp_llsc_mb();
 306
 307         return result;
 308 }
 309
 310 #define atomic_cmpxchg(v, o, n) (cmpxchg(&((v)->counter), (o), (n)))
 311 #define atomic_xchg(v, new) (xchg(&((v)->counter), (new)))
 312
 313 /**
 314  * atomic_add_unless - add unless the number is a given value
 315  * @v: pointer of type atomic_t
 316  * @a: the amount to add to v...
 317  * @u: ...unless v is equal to u.
 318  *
 319  * Atomically adds @a to @v, so long as it was not @u.
 320  * Returns non-zero if @v was not @u, and zero otherwise.
 321  */
 322 static __inline__ int atomic_add_unless(atomic_t *v, int a, int u)
 323 {
 324         int c, old;
 325         c = atomic_read(v);
 326         for (;;) {
 327                 if (unlikely(c == (u)))
 328                         break;
 329                 old = atomic_cmpxchg((v), c, c + (a));
 330                 if (likely(old == c))
 331                         break;
 332                 c = old;
 333         }
 334         return c != (u);
 335 }
 336 #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
 337
 338 #define atomic_dec_return(v) atomic_sub_return(1, (v))
 339 #define atomic_inc_return(v) atomic_add_return(1, (v))
 340
 341 /*
 342  * atomic_sub_and_test - subtract value from variable and test result
 343  * @i: integer value to subtract
 344  * @v: pointer of type atomic_t
 345  *
 346  * Atomically subtracts @i from @v and returns
 347  * true if the result is zero, or false for all
 348  * other cases.
 349  */
 350 #define atomic_sub_and_test(i, v) (atomic_sub_return((i), (v)) == 0)
 351
 352 /*
 353  * atomic_inc_and_test - increment and test
 354  * @v: pointer of type atomic_t
 355  *
 356  * Atomically increments @v by 1
 357  * and returns true if the result is zero, or false for all
 358  * other cases.
 359  */
 360 #define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)
 361
 362 /*
 363  * atomic_dec_and_test - decrement by 1 and test
 364  * @v: pointer of type atomic_t
 365  *
 366  * Atomically decrements @v by 1 and
 367  * returns true if the result is 0, or false for all other
 368  * cases.
 369  */
 370 #define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)
 371
 372 /*
 373  * atomic_dec_if_positive - decrement by 1 if old value positive
 374  * @v: pointer of type atomic_t
 375  */
 376 #define atomic_dec_if_positive(v)       atomic_sub_if_positive(1, v)
 377
 378 /*
 379  * atomic_inc - increment atomic variable
 380  * @v: pointer of type atomic_t
 381  *
 382  * Atomically increments @v by 1.
 383  */
 384 #define atomic_inc(v) atomic_add(1, (v))
 385
 386 /*
 387  * atomic_dec - decrement and test
 388  * @v: pointer of type atomic_t
 389  *
 390  * Atomically decrements @v by 1.
 391  */
 392 #define atomic_dec(v) atomic_sub(1, (v))
 393
 394 /*
 395  * atomic_add_negative - add and test if negative
 396  * @v: pointer of type atomic_t
 397  * @i: integer value to add
 398  *
 399  * Atomically adds @i to @v and returns true
 400  * if the result is negative, or false when
 401  * result is greater than or equal to zero.
 402  */
 403 #define atomic_add_negative(i, v) (atomic_add_return(i, (v)) < 0)
 404
 405 #ifdef CONFIG_64BIT
 406
 407 typedef struct { volatile long counter; } atomic64_t;
 408
 409 #define ATOMIC64_INIT(i)    { (i) }
 410
 411 /*
 412  * atomic64_read - read atomic variable
 413  * @v: pointer of type atomic64_t
 414  *
 415  */
 416 #define atomic64_read(v)        ((v)->counter)
 417
 418 /*
 419  * atomic64_set - set atomic variable
 420  * @v: pointer of type atomic64_t
 421  * @i: required value
 422  */
 423 #define atomic64_set(v, i)      ((v)->counter = (i))
 424
 425 /*
 426  * atomic64_add - add integer to atomic variable
 427  * @i: integer value to add
 428  * @v: pointer of type atomic64_t
 429  *
 430  * Atomically adds @i to @v.
 431  */
 432 static __inline__ void atomic64_add(long i, atomic64_t * v)
 433 {
 434         if (cpu_has_llsc && R10000_LLSC_WAR) {
 435                 unsigned long temp;
 436
 437                 __asm__ __volatile__(
 438                 "       .set    mips3                                   \n"
 439                 "1:     lld     %0, %1          # atomic64_add          \n"
 440                 "       addu    %0, %2                                  \n"
 441                 "       scd     %0, %1                                  \n"
 442                 "       beqzl   %0, 1b                                  \n"
 443                 "       .set    mips0                                   \n"
 444                 : "=&r" (temp), "=m" (v->counter)
 445                 : "Ir" (i), "m" (v->counter));
 446         } else if (cpu_has_llsc) {
 447                 unsigned long temp;
 448
 449                 __asm__ __volatile__(
 450                 "       .set    mips3                                   \n"
 451                 "1:     lld     %0, %1          # atomic64_add          \n"
 452                 "       addu    %0, %2                                  \n"
 453                 "       scd     %0, %1                                  \n"
 454                 "       beqz    %0, 2f                                  \n"
 455                 "       .subsection 2                                   \n"
 456                 "2:     b       1b                                      \n"
 457                 "       .previous                                       \n"
 458                 "       .set    mips0                                   \n"
 459                 : "=&r" (temp), "=m" (v->counter)
 460                 : "Ir" (i), "m" (v->counter));
 461         } else {
 462                 unsigned long flags;
 463
 464                 raw_local_irq_save(flags);
 465                 v->counter += i;
 466                 raw_local_irq_restore(flags);
 467         }
 468 }
 469
 470 /*
 471  * atomic64_sub - subtract the atomic variable
 472  * @i: integer value to subtract
 473  * @v: pointer of type atomic64_t
 474  *
 475  * Atomically subtracts @i from @v.
 476  */
 477 static __inline__ void atomic64_sub(long i, atomic64_t * v)
 478 {
 479         if (cpu_has_llsc && R10000_LLSC_WAR) {
 480                 unsigned long temp;
 481
 482                 __asm__ __volatile__(
 483                 "       .set    mips3                                   \n"
 484                 "1:     lld     %0, %1          # atomic64_sub          \n"
 485                 "       subu    %0, %2                                  \n"
 486                 "       scd     %0, %1                                  \n"
 487                 "       beqzl   %0, 1b                                  \n"
 488                 "       .set    mips0                                   \n"
 489                 : "=&r" (temp), "=m" (v->counter)
 490                 : "Ir" (i), "m" (v->counter));
 491         } else if (cpu_has_llsc) {
 492                 unsigned long temp;
 493
 494                 __asm__ __volatile__(
 495                 "       .set    mips3                                   \n"
 496                 "1:     lld     %0, %1          # atomic64_sub          \n"
 497                 "       subu    %0, %2                                  \n"
 498                 "       scd     %0, %1                                  \n"
 499                 "       beqz    %0, 2f                                  \n"
 500                 "       .subsection 2                                   \n"
 501                 "2:     b       1b                                      \n"
 502                 "       .previous                                       \n"
 503                 "       .set    mips0                                   \n"
 504                 : "=&r" (temp), "=m" (v->counter)
 505                 : "Ir" (i), "m" (v->counter));
 506         } else {
 507                 unsigned long flags;
 508
 509                 raw_local_irq_save(flags);
 510                 v->counter -= i;
 511                 raw_local_irq_restore(flags);
 512         }
 513 }
 514
 515 /*
 516  * Same as above, but return the result value
 517  */
 518 static __inline__ long atomic64_add_return(long i, atomic64_t * v)
 519 {
 520         unsigned long result;
 521
 522         smp_llsc_mb();
 523
 524         if (cpu_has_llsc && R10000_LLSC_WAR) {
 525                 unsigned long temp;
 526
 527                 __asm__ __volatile__(
 528                 "       .set    mips3                                   \n"
 529                 "1:     lld     %1, %2          # atomic64_add_return   \n"
 530                 "       addu    %0, %1, %3                              \n"
 531                 "       scd     %0, %2                                  \n"
 532                 "       beqzl   %0, 1b                                  \n"
 533                 "       addu    %0, %1, %3                              \n"
 534                 "       .set    mips0                                   \n"
 535                 : "=&r" (result), "=&r" (temp), "=m" (v->counter)
 536                 : "Ir" (i), "m" (v->counter)
 537                 : "memory");
 538         } else if (cpu_has_llsc) {
 539                 unsigned long temp;
 540
 541                 __asm__ __volatile__(
 542                 "       .set    mips3                                   \n"
 543                 "1:     lld     %1, %2          # atomic64_add_return   \n"
 544                 "       addu    %0, %1, %3                              \n"
 545                 "       scd     %0, %2                                  \n"
 546                 "       beqz    %0, 2f                                  \n"
 547                 "       addu    %0, %1, %3                              \n"
 548                 "       .subsection 2                                   \n"
 549                 "2:     b       1b                                      \n"
 550                 "       .previous                                       \n"
 551                 "       .set    mips0                                   \n"
 552                 : "=&r" (result), "=&r" (temp), "=m" (v->counter)
 553                 : "Ir" (i), "m" (v->counter)
 554                 : "memory");
 555         } else {
 556                 unsigned long flags;
 557
 558                 raw_local_irq_save(flags);
 559                 result = v->counter;
 560                 result += i;
 561                 v->counter = result;
 562                 raw_local_irq_restore(flags);
 563         }
 564
 565         smp_llsc_mb();
 566
 567         return result;
 568 }
 569
 570 static __inline__ long atomic64_sub_return(long i, atomic64_t * v)
 571 {
 572         unsigned long result;
 573
 574         smp_llsc_mb();
 575
 576         if (cpu_has_llsc && R10000_LLSC_WAR) {
 577                 unsigned long temp;
 578
 579                 __asm__ __volatile__(
 580                 "       .set    mips3                                   \n"
 581                 "1:     lld     %1, %2          # atomic64_sub_return   \n"
 582                 "       subu    %0, %1, %3                              \n"
 583                 "       scd     %0, %2                                  \n"
 584                 "       beqzl   %0, 1b                                  \n"
 585                 "       subu    %0, %1, %3                              \n"
 586                 "       .set    mips0                                   \n"
 587                 : "=&r" (result), "=&r" (temp), "=m" (v->counter)
 588                 : "Ir" (i), "m" (v->counter)
 589                 : "memory");
 590         } else if (cpu_has_llsc) {
 591                 unsigned long temp;
 592
 593                 __asm__ __volatile__(
 594                 "       .set    mips3                                   \n"
 595                 "1:     lld     %1, %2          # atomic64_sub_return   \n"
 596                 "       subu    %0, %1, %3                              \n"
 597                 "       scd     %0, %2                                  \n"
 598                 "       beqz    %0, 2f                                  \n"
 599                 "       subu    %0, %1, %3                              \n"
 600                 "       .subsection 2                                   \n"
 601                 "2:     b       1b                                      \n"
 602                 "       .previous                                       \n"
 603                 "       .set    mips0                                   \n"
 604                 : "=&r" (result), "=&r" (temp), "=m" (v->counter)
 605                 : "Ir" (i), "m" (v->counter)
 606                 : "memory");
 607         } else {
 608                 unsigned long flags;
 609
 610                 raw_local_irq_save(flags);
 611                 result = v->counter;
 612                 result -= i;
 613                 v->counter = result;
 614                 raw_local_irq_restore(flags);
 615         }
 616
 617         smp_llsc_mb();
 618
 619         return result;
 620 }
 621
 622 /*
 623  * atomic64_sub_if_positive - conditionally subtract integer from atomic variable
 624  * @i: integer value to subtract
 625  * @v: pointer of type atomic64_t
 626  *
 627  * Atomically test @v and subtract @i if @v is greater or equal than @i.
 628  * The function returns the old value of @v minus @i.
 629  */
 630 static __inline__ long atomic64_sub_if_positive(long i, atomic64_t * v)
 631 {
 632         unsigned long result;
 633
 634         smp_llsc_mb();
 635
 636         if (cpu_has_llsc && R10000_LLSC_WAR) {
 637                 unsigned long temp;
 638
 639                 __asm__ __volatile__(
 640                 "       .set    mips3                                   \n"
 641                 "1:     lld     %1, %2          # atomic64_sub_if_positive\n"
 642                 "       dsubu   %0, %1, %3                              \n"
 643                 "       bltz    %0, 1f                                  \n"
 644                 "       scd     %0, %2                                  \n"
 645                 "       .set    noreorder                               \n"
 646                 "       beqzl   %0, 1b                                  \n"
 647                 "        dsubu  %0, %1, %3                              \n"
 648                 "       .set    reorder                                 \n"
 649                 "1:                                                     \n"
 650                 "       .set    mips0                                   \n"
 651                 : "=&r" (result), "=&r" (temp), "=m" (v->counter)
 652                 : "Ir" (i), "m" (v->counter)
 653                 : "memory");
 654         } else if (cpu_has_llsc) {
 655                 unsigned long temp;
 656
 657                 __asm__ __volatile__(
 658                 "       .set    mips3                                   \n"
 659                 "1:     lld     %1, %2          # atomic64_sub_if_positive\n"
 660                 "       dsubu   %0, %1, %3                              \n"
 661                 "       bltz    %0, 1f                                  \n"
 662                 "       scd     %0, %2                                  \n"
 663                 "       .set    noreorder                               \n"
 664                 "       beqz    %0, 2f                                  \n"
 665                 "        dsubu  %0, %1, %3                              \n"
 666                 "       .set    reorder                                 \n"
 667                 "1:                                                     \n"
 668                 "       .subsection 2                                   \n"
 669                 "2:     b       1b                                      \n"
 670                 "       .previous                                       \n"
 671                 "       .set    mips0                                   \n"
 672                 : "=&r" (result), "=&r" (temp), "=m" (v->counter)
 673                 : "Ir" (i), "m" (v->counter)
 674                 : "memory");
 675         } else {
 676                 unsigned long flags;
 677
 678                 raw_local_irq_save(flags);
 679                 result = v->counter;
 680                 result -= i;
 681                 if (result >= 0)
 682                         v->counter = result;
 683                 raw_local_irq_restore(flags);
 684         }
 685
 686         smp_llsc_mb();
 687
 688         return result;
 689 }
 690
 691 #define atomic64_cmpxchg(v, o, n) \
 692         ((__typeof__((v)->counter))cmpxchg(&((v)->counter), (o), (n)))
 693 #define atomic64_xchg(v, new) (xchg(&((v)->counter), (new)))
 694
 695 /**
 696  * atomic64_add_unless - add unless the number is a given value
 697  * @v: pointer of type atomic64_t
 698  * @a: the amount to add to v...
 699  * @u: ...unless v is equal to u.
 700  *
 701  * Atomically adds @a to @v, so long as it was not @u.
 702  * Returns non-zero if @v was not @u, and zero otherwise.
 703  */
 704 static __inline__ int atomic64_add_unless(atomic64_t *v, long a, long u)
 705 {
 706         long c, old;
 707         c = atomic64_read(v);
 708         for (;;) {
 709                 if (unlikely(c == (u)))
 710                         break;
 711                 old = atomic64_cmpxchg((v), c, c + (a));
 712                 if (likely(old == c))
 713                         break;
 714                 c = old;
 715         }
 716         return c != (u);
 717 }
 718
 719 #define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
 720
 721 #define atomic64_dec_return(v) atomic64_sub_return(1, (v))
 722 #define atomic64_inc_return(v) atomic64_add_return(1, (v))
 723
 724 /*
 725  * atomic64_sub_and_test - subtract value from variable and test result
 726  * @i: integer value to subtract
 727  * @v: pointer of type atomic64_t
 728  *
 729  * Atomically subtracts @i from @v and returns
 730  * true if the result is zero, or false for all
 731  * other cases.
 732  */
 733 #define atomic64_sub_and_test(i, v) (atomic64_sub_return((i), (v)) == 0)
 734
 735 /*
 736  * atomic64_inc_and_test - increment and test
 737  * @v: pointer of type atomic64_t
 738  *
 739  * Atomically increments @v by 1
 740  * and returns true if the result is zero, or false for all
 741  * other cases.
 742  */
 743 #define atomic64_inc_and_test(v) (atomic64_inc_return(v) == 0)
 744
 745 /*
 746  * atomic64_dec_and_test - decrement by 1 and test
 747  * @v: pointer of type atomic64_t
 748  *
 749  * Atomically decrements @v by 1 and
 750  * returns true if the result is 0, or false for all other
 751  * cases.
 752  */
 753 #define atomic64_dec_and_test(v) (atomic64_sub_return(1, (v)) == 0)
 754
 755 /*
 756  * atomic64_dec_if_positive - decrement by 1 if old value positive
 757  * @v: pointer of type atomic64_t
 758  */
 759 #define atomic64_dec_if_positive(v)     atomic64_sub_if_positive(1, v)
 760
 761 /*
 762  * atomic64_inc - increment atomic variable
 763  * @v: pointer of type atomic64_t
 764  *
 765  * Atomically increments @v by 1.
 766  */
 767 #define atomic64_inc(v) atomic64_add(1, (v))
 768
 769 /*
 770  * atomic64_dec - decrement and test
 771  * @v: pointer of type atomic64_t
 772  *
 773  * Atomically decrements @v by 1.
 774  */
 775 #define atomic64_dec(v) atomic64_sub(1, (v))
 776
 777 /*
 778  * atomic64_add_negative - add and test if negative
 779  * @v: pointer of type atomic64_t
 780  * @i: integer value to add
 781  *
 782  * Atomically adds @i to @v and returns true
 783  * if the result is negative, or false when
 784  * result is greater than or equal to zero.
 785  */
 786 #define atomic64_add_negative(i, v) (atomic64_add_return(i, (v)) < 0)
 787
 788 #endif /* CONFIG_64BIT */
 789
 790 /*
 791  * atomic*_return operations are serializing but not the non-*_return
 792  * versions.
 793  */
 794 #define smp_mb__before_atomic_dec()     smp_llsc_mb()
 795 #define smp_mb__after_atomic_dec()      smp_llsc_mb()
 796 #define smp_mb__before_atomic_inc()     smp_llsc_mb()
 797 #define smp_mb__after_atomic_inc()      smp_llsc_mb()
 798
 799 #include <asm-generic/atomic.h>
 800
 801 #endif /* _ASM_ATOMIC_H */