include/asm-powerpc/bitops.h

   1 /*
   2  * PowerPC atomic bit operations.
   3  *
   4  * Merged version by David Gibson <david@gibson.dropbear.id.au>.
   5  * Based on ppc64 versions by: Dave Engebretsen, Todd Inglett, Don
   6  * Reed, Pat McCarthy, Peter Bergner, Anton Blanchard.  They
   7  * originally took it from the ppc32 code.
   8  *
   9  * Within a word, bits are numbered LSB first.  Lot's of places make
  10  * this assumption by directly testing bits with (val & (1<<nr)).
  11  * This can cause confusion for large (> 1 word) bitmaps on a
  12  * big-endian system because, unlike little endian, the number of each
  13  * bit depends on the word size.
  14  *
  15  * The bitop functions are defined to work on unsigned longs, so for a
  16  * ppc64 system the bits end up numbered:
  17  *   |63..............0|127............64|191...........128|255...........196|
  18  * and on ppc32:
  19  *   |31.....0|63....31|95....64|127...96|159..128|191..160|223..192|255..224|
  20  *
  21  * There are a few little-endian macros used mostly for filesystem
  22  * bitmaps, these work on similar bit arrays layouts, but
  23  * byte-oriented:
  24  *   |7...0|15...8|23...16|31...24|39...32|47...40|55...48|63...56|
  25  *
  26  * The main difference is that bit 3-5 (64b) or 3-4 (32b) in the bit
  27  * number field needs to be reversed compared to the big-endian bit
  28  * fields. This can be achieved by XOR with 0x38 (64b) or 0x18 (32b).
  29  *
  30  * This program is free software; you can redistribute it and/or
  31  * modify it under the terms of the GNU General Public License
  32  * as published by the Free Software Foundation; either version
  33  * 2 of the License, or (at your option) any later version.
  34  */
  35
  36 #ifndef _ASM_POWERPC_BITOPS_H
  37 #define _ASM_POWERPC_BITOPS_H
  38
  39 #ifdef __KERNEL__
  40
  41 #include <linux/compiler.h>
  42 #include <asm/asm-compat.h>
  43 #include <asm/synch.h>
  44
  45 /*
  46  * clear_bit doesn't imply a memory barrier
  47  */
  48 #define smp_mb__before_clear_bit()      smp_mb()
  49 #define smp_mb__after_clear_bit()       smp_mb()
  50
  51 #define BITOP_MASK(nr)          (1UL << ((nr) % BITS_PER_LONG))
  52 #define BITOP_WORD(nr)          ((nr) / BITS_PER_LONG)
  53 #define BITOP_LE_SWIZZLE        ((BITS_PER_LONG-1) & ~0x7)
  54
  55 static __inline__ void set_bit(int nr, volatile unsigned long *addr)
  56 {
  57         unsigned long old;
  58         unsigned long mask = BITOP_MASK(nr);
  59         unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
  60
  61         __asm__ __volatile__(
  62 "1:"    PPC_LLARX "%0,0,%3      # set_bit\n"
  63         "or     %0,%0,%2\n"
  64         PPC405_ERR77(0,%3)
  65         PPC_STLCX "%0,0,%3\n"
  66         "bne-   1b"
  67         : "=&r" (old), "+m" (*p)
  68         : "r" (mask), "r" (p)
  69         : "cc" );
  70 }
  71
  72 static __inline__ void clear_bit(int nr, volatile unsigned long *addr)
  73 {
  74         unsigned long old;
  75         unsigned long mask = BITOP_MASK(nr);
  76         unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
  77
  78         __asm__ __volatile__(
  79 "1:"    PPC_LLARX "%0,0,%3      # clear_bit\n"
  80         "andc   %0,%0,%2\n"
  81         PPC405_ERR77(0,%3)
  82         PPC_STLCX "%0,0,%3\n"
  83         "bne-   1b"
  84         : "=&r" (old), "+m" (*p)
  85         : "r" (mask), "r" (p)
  86         : "cc" );
  87 }
  88
  89 static __inline__ void change_bit(int nr, volatile unsigned long *addr)
  90 {
  91         unsigned long old;
  92         unsigned long mask = BITOP_MASK(nr);
  93         unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
  94
  95         __asm__ __volatile__(
  96 "1:"    PPC_LLARX "%0,0,%3      # change_bit\n"
  97         "xor    %0,%0,%2\n"
  98         PPC405_ERR77(0,%3)
  99         PPC_STLCX "%0,0,%3\n"
 100         "bne-   1b"
 101         : "=&r" (old), "+m" (*p)
 102         : "r" (mask), "r" (p)
 103         : "cc" );
 104 }
 105
 106 static __inline__ int test_and_set_bit(unsigned long nr,
 107                                        volatile unsigned long *addr)
 108 {
 109         unsigned long old, t;
 110         unsigned long mask = BITOP_MASK(nr);
 111         unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
 112
 113         __asm__ __volatile__(
 114         LWSYNC_ON_SMP
 115 "1:"    PPC_LLARX "%0,0,%3              # test_and_set_bit\n"
 116         "or     %1,%0,%2 \n"
 117         PPC405_ERR77(0,%3)
 118         PPC_STLCX "%1,0,%3 \n"
 119         "bne-   1b"
 120         ISYNC_ON_SMP
 121         : "=&r" (old), "=&r" (t)
 122         : "r" (mask), "r" (p)
 123         : "cc", "memory");
 124
 125         return (old & mask) != 0;
 126 }
 127
 128 static __inline__ int test_and_clear_bit(unsigned long nr,
 129                                          volatile unsigned long *addr)
 130 {
 131         unsigned long old, t;
 132         unsigned long mask = BITOP_MASK(nr);
 133         unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
 134
 135         __asm__ __volatile__(
 136         LWSYNC_ON_SMP
 137 "1:"    PPC_LLARX "%0,0,%3              # test_and_clear_bit\n"
 138         "andc   %1,%0,%2 \n"
 139         PPC405_ERR77(0,%3)
 140         PPC_STLCX "%1,0,%3 \n"
 141         "bne-   1b"
 142         ISYNC_ON_SMP
 143         : "=&r" (old), "=&r" (t)
 144         : "r" (mask), "r" (p)
 145         : "cc", "memory");
 146
 147         return (old & mask) != 0;
 148 }
 149
 150 static __inline__ int test_and_change_bit(unsigned long nr,
 151                                           volatile unsigned long *addr)
 152 {
 153         unsigned long old, t;
 154         unsigned long mask = BITOP_MASK(nr);
 155         unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
 156
 157         __asm__ __volatile__(
 158         LWSYNC_ON_SMP
 159 "1:"    PPC_LLARX "%0,0,%3              # test_and_change_bit\n"
 160         "xor    %1,%0,%2 \n"
 161         PPC405_ERR77(0,%3)
 162         PPC_STLCX "%1,0,%3 \n"
 163         "bne-   1b"
 164         ISYNC_ON_SMP
 165         : "=&r" (old), "=&r" (t)
 166         : "r" (mask), "r" (p)
 167         : "cc", "memory");
 168
 169         return (old & mask) != 0;
 170 }
 171
 172 static __inline__ void set_bits(unsigned long mask, unsigned long *addr)
 173 {
 174         unsigned long old;
 175
 176         __asm__ __volatile__(
 177 "1:"    PPC_LLARX "%0,0,%3         # set_bits\n"
 178         "or     %0,%0,%2\n"
 179         PPC_STLCX "%0,0,%3\n"
 180         "bne-   1b"
 181         : "=&r" (old), "+m" (*addr)
 182         : "r" (mask), "r" (addr)
 183         : "cc");
 184 }
 185
 186 #include <asm-generic/bitops/non-atomic.h>
 187
 188 /*
 189  * Return the zero-based bit position (LE, not IBM bit numbering) of
 190  * the most significant 1-bit in a double word.
 191  */
 192 static __inline__ __attribute__((const))
 193 int __ilog2(unsigned long x)
 194 {
 195         int lz;
 196
 197         asm (PPC_CNTLZL "%0,%1" : "=r" (lz) : "r" (x));
 198         return BITS_PER_LONG - 1 - lz;
 199 }
 200
 201 static inline __attribute__((const))
 202 int __ilog2_u32(u32 n)
 203 {
 204         int bit;
 205         asm ("cntlzw %0,%1" : "=r" (bit) : "r" (n));
 206         return 31 - bit;
 207 }
 208
 209 #ifdef __powerpc64__
 210 static inline __attribute__((const))
 211 int __ilog2_u64(u64 n)
 212 {
 213         int bit;
 214         asm ("cntlzd %0,%1" : "=r" (bit) : "r" (n));
 215         return 63 - bit;
 216 }
 217 #endif
 218
 219 /*
 220  * Determines the bit position of the least significant 0 bit in the
 221  * specified double word. The returned bit position will be
 222  * zero-based, starting from the right side (63/31 - 0).
 223  */
 224 static __inline__ unsigned long ffz(unsigned long x)
 225 {
 226         /* no zero exists anywhere in the 8 byte area. */
 227         if ((x = ~x) == 0)
 228                 return BITS_PER_LONG;
 229
 230         /*
 231          * Calculate the bit position of the least signficant '1' bit in x
 232          * (since x has been changed this will actually be the least signficant
 233          * '0' bit in * the original x).  Note: (x & -x) gives us a mask that
 234          * is the least significant * (RIGHT-most) 1-bit of the value in x.
 235          */
 236         return __ilog2(x & -x);
 237 }
 238
 239 static __inline__ int __ffs(unsigned long x)
 240 {
 241         return __ilog2(x & -x);
 242 }
 243
 244 /*
 245  * ffs: find first bit set. This is defined the same way as
 246  * the libc and compiler builtin ffs routines, therefore
 247  * differs in spirit from the above ffz (man ffs).
 248  */
 249 static __inline__ int ffs(int x)
 250 {
 251         unsigned long i = (unsigned long)x;
 252         return __ilog2(i & -i) + 1;
 253 }
 254
 255 /*
 256  * fls: find last (most-significant) bit set.
 257  * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
 258  */
 259 static __inline__ int fls(unsigned int x)
 260 {
 261         int lz;
 262
 263         asm ("cntlzw %0,%1" : "=r" (lz) : "r" (x));
 264         return 32 - lz;
 265 }
 266 #include <asm-generic/bitops/fls64.h>
 267
 268 #include <asm-generic/bitops/hweight.h>
 269
 270 #define find_first_zero_bit(addr, size) find_next_zero_bit((addr), (size), 0)
 271 unsigned long find_next_zero_bit(const unsigned long *addr,
 272                                  unsigned long size, unsigned long offset);
 273 /**
 274  * find_first_bit - find the first set bit in a memory region
 275  * @addr: The address to start the search at
 276  * @size: The maximum size to search
 277  *
 278  * Returns the bit-number of the first set bit, not the number of the byte
 279  * containing a bit.
 280  */
 281 #define find_first_bit(addr, size) find_next_bit((addr), (size), 0)
 282 unsigned long find_next_bit(const unsigned long *addr,
 283                             unsigned long size, unsigned long offset);
 284
 285 /* Little-endian versions */
 286
 287 static __inline__ int test_le_bit(unsigned long nr,
 288                                   __const__ unsigned long *addr)
 289 {
 290         __const__ unsigned char *tmp = (__const__ unsigned char *) addr;
 291         return (tmp[nr >> 3] >> (nr & 7)) & 1;
 292 }
 293
 294 #define __set_le_bit(nr, addr) \
 295         __set_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
 296 #define __clear_le_bit(nr, addr) \
 297         __clear_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
 298
 299 #define test_and_set_le_bit(nr, addr) \
 300         test_and_set_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
 301 #define test_and_clear_le_bit(nr, addr) \
 302         test_and_clear_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
 303
 304 #define __test_and_set_le_bit(nr, addr) \
 305         __test_and_set_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
 306 #define __test_and_clear_le_bit(nr, addr) \
 307         __test_and_clear_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
 308
 309 #define find_first_zero_le_bit(addr, size) generic_find_next_zero_le_bit((addr), (size), 0)
 310 unsigned long generic_find_next_zero_le_bit(const unsigned long *addr,
 311                                     unsigned long size, unsigned long offset);
 312
 313 /* Bitmap functions for the ext2 filesystem */
 314
 315 #define ext2_set_bit(nr,addr) \
 316         __test_and_set_le_bit((nr), (unsigned long*)addr)
 317 #define ext2_clear_bit(nr, addr) \
 318         __test_and_clear_le_bit((nr), (unsigned long*)addr)
 319
 320 #define ext2_set_bit_atomic(lock, nr, addr) \
 321         test_and_set_le_bit((nr), (unsigned long*)addr)
 322 #define ext2_clear_bit_atomic(lock, nr, addr) \
 323         test_and_clear_le_bit((nr), (unsigned long*)addr)
 324
 325 #define ext2_test_bit(nr, addr)      test_le_bit((nr),(unsigned long*)addr)
 326
 327 #define ext2_find_first_zero_bit(addr, size) \
 328         find_first_zero_le_bit((unsigned long*)addr, size)
 329 #define ext2_find_next_zero_bit(addr, size, off) \
 330         generic_find_next_zero_le_bit((unsigned long*)addr, size, off)
 331
 332 /* Bitmap functions for the minix filesystem.  */
 333
 334 #define minix_test_and_set_bit(nr,addr) \
 335         __test_and_set_le_bit(nr, (unsigned long *)addr)
 336 #define minix_set_bit(nr,addr) \
 337         __set_le_bit(nr, (unsigned long *)addr)
 338 #define minix_test_and_clear_bit(nr,addr) \
 339         __test_and_clear_le_bit(nr, (unsigned long *)addr)
 340 #define minix_test_bit(nr,addr) \
 341         test_le_bit(nr, (unsigned long *)addr)
 342
 343 #define minix_find_first_zero_bit(addr,size) \
 344         find_first_zero_le_bit((unsigned long *)addr, size)
 345
 346 #include <asm-generic/bitops/sched.h>
 347
 348 #endif /* __KERNEL__ */
 349
 350 #endif /* _ASM_POWERPC_BITOPS_H */