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 #ifndef _LINUX_BITOPS_H 42 #error only <linux/bitops.h> can be included directly 43 #endif 44 45 #include <linux/compiler.h> 46 #include <asm/asm-compat.h> 47 #include <asm/synch.h> 48 49 /* 50 * clear_bit doesn't imply a memory barrier 51 */ 52 #define smp_mb__before_clear_bit() smp_mb() 53 #define smp_mb__after_clear_bit() smp_mb() 54 55 #define BITOP_MASK(nr) (1UL << ((nr) % BITS_PER_LONG)) 56 #define BITOP_WORD(nr) ((nr) / BITS_PER_LONG) 57 #define BITOP_LE_SWIZZLE ((BITS_PER_LONG-1) & ~0x7) 58 59 /* Macro for generating the ***_bits() functions */ 60 #define DEFINE_BITOP(fn, op, prefix, postfix) \ 61 static __inline__ void fn(unsigned long mask, \ 62 volatile unsigned long *_p) \ 63 { \ 64 unsigned long old; \ 65 unsigned long *p = (unsigned long *)_p; \ 66 __asm__ __volatile__ ( \ 67 prefix \ 68 "1:" PPC_LLARX "%0,0,%3\n" \ 69 stringify_in_c(op) "%0,%0,%2\n" \ 70 PPC405_ERR77(0,%3) \ 71 PPC_STLCX "%0,0,%3\n" \ 72 "bne- 1b\n" \ 73 postfix \ 74 : "=&r" (old), "+m" (*p) \ 75 : "r" (mask), "r" (p) \ 76 : "cc", "memory"); \ 77 } 78 79 DEFINE_BITOP(set_bits, or, "", "") 80 DEFINE_BITOP(clear_bits, andc, "", "") 81 DEFINE_BITOP(clear_bits_unlock, andc, LWSYNC_ON_SMP, "") 82 DEFINE_BITOP(change_bits, xor, "", "") 83 84 static __inline__ void set_bit(int nr, volatile unsigned long *addr) 85 { 86 set_bits(BITOP_MASK(nr), addr + BITOP_WORD(nr)); 87 } 88 89 static __inline__ void clear_bit(int nr, volatile unsigned long *addr) 90 { 91 clear_bits(BITOP_MASK(nr), addr + BITOP_WORD(nr)); 92 } 93 94 static __inline__ void clear_bit_unlock(int nr, volatile unsigned long *addr) 95 { 96 clear_bits_unlock(BITOP_MASK(nr), addr + BITOP_WORD(nr)); 97 } 98 99 static __inline__ void change_bit(int nr, volatile unsigned long *addr) 100 { 101 change_bits(BITOP_MASK(nr), addr + BITOP_WORD(nr)); 102 } 103 104 /* Like DEFINE_BITOP(), with changes to the arguments to 'op' and the output 105 * operands. */ 106 #define DEFINE_TESTOP(fn, op, prefix, postfix) \ 107 static __inline__ unsigned long fn( \ 108 unsigned long mask, \ 109 volatile unsigned long *_p) \ 110 { \ 111 unsigned long old, t; \ 112 unsigned long *p = (unsigned long *)_p; \ 113 __asm__ __volatile__ ( \ 114 prefix \ 115 "1:" PPC_LLARX "%0,0,%3\n" \ 116 stringify_in_c(op) "%1,%0,%2\n" \ 117 PPC405_ERR77(0,%3) \ 118 PPC_STLCX "%1,0,%3\n" \ 119 "bne- 1b\n" \ 120 postfix \ 121 : "=&r" (old), "=&r" (t) \ 122 : "r" (mask), "r" (p) \ 123 : "cc", "memory"); \ 124 return (old & mask); \ 125 } 126 127 DEFINE_TESTOP(test_and_set_bits, or, LWSYNC_ON_SMP, ISYNC_ON_SMP) 128 DEFINE_TESTOP(test_and_set_bits_lock, or, "", ISYNC_ON_SMP) 129 DEFINE_TESTOP(test_and_clear_bits, andc, LWSYNC_ON_SMP, ISYNC_ON_SMP) 130 DEFINE_TESTOP(test_and_change_bits, xor, LWSYNC_ON_SMP, ISYNC_ON_SMP) 131 132 static __inline__ int test_and_set_bit(unsigned long nr, 133 volatile unsigned long *addr) 134 { 135 return test_and_set_bits(BITOP_MASK(nr), addr + BITOP_WORD(nr)) != 0; 136 } 137 138 static __inline__ int test_and_set_bit_lock(unsigned long nr, 139 volatile unsigned long *addr) 140 { 141 return test_and_set_bits_lock(BITOP_MASK(nr), 142 addr + BITOP_WORD(nr)) != 0; 143 } 144 145 static __inline__ int test_and_clear_bit(unsigned long nr, 146 volatile unsigned long *addr) 147 { 148 return test_and_clear_bits(BITOP_MASK(nr), addr + BITOP_WORD(nr)) != 0; 149 } 150 151 static __inline__ int test_and_change_bit(unsigned long nr, 152 volatile unsigned long *addr) 153 { 154 return test_and_change_bits(BITOP_MASK(nr), addr + BITOP_WORD(nr)) != 0; 155 } 156 157 #include <asm-generic/bitops/non-atomic.h> 158 159 static __inline__ void __clear_bit_unlock(int nr, volatile unsigned long *addr) 160 { 161 __asm__ __volatile__(LWSYNC_ON_SMP "" ::: "memory"); 162 __clear_bit(nr, addr); 163 } 164 165 /* 166 * Return the zero-based bit position (LE, not IBM bit numbering) of 167 * the most significant 1-bit in a double word. 168 */ 169 static __inline__ __attribute__((const)) 170 int __ilog2(unsigned long x) 171 { 172 int lz; 173 174 asm (PPC_CNTLZL "%0,%1" : "=r" (lz) : "r" (x)); 175 return BITS_PER_LONG - 1 - lz; 176 } 177 178 static inline __attribute__((const)) 179 int __ilog2_u32(u32 n) 180 { 181 int bit; 182 asm ("cntlzw %0,%1" : "=r" (bit) : "r" (n)); 183 return 31 - bit; 184 } 185 186 #ifdef __powerpc64__ 187 static inline __attribute__((const)) 188 int __ilog2_u64(u64 n) 189 { 190 int bit; 191 asm ("cntlzd %0,%1" : "=r" (bit) : "r" (n)); 192 return 63 - bit; 193 } 194 #endif 195 196 /* 197 * Determines the bit position of the least significant 0 bit in the 198 * specified double word. The returned bit position will be 199 * zero-based, starting from the right side (63/31 - 0). 200 */ 201 static __inline__ unsigned long ffz(unsigned long x) 202 { 203 /* no zero exists anywhere in the 8 byte area. */ 204 if ((x = ~x) == 0) 205 return BITS_PER_LONG; 206 207 /* 208 * Calculate the bit position of the least signficant '1' bit in x 209 * (since x has been changed this will actually be the least signficant 210 * '0' bit in * the original x). Note: (x & -x) gives us a mask that 211 * is the least significant * (RIGHT-most) 1-bit of the value in x. 212 */ 213 return __ilog2(x & -x); 214 } 215 216 static __inline__ int __ffs(unsigned long x) 217 { 218 return __ilog2(x & -x); 219 } 220 221 /* 222 * ffs: find first bit set. This is defined the same way as 223 * the libc and compiler builtin ffs routines, therefore 224 * differs in spirit from the above ffz (man ffs). 225 */ 226 static __inline__ int ffs(int x) 227 { 228 unsigned long i = (unsigned long)x; 229 return __ilog2(i & -i) + 1; 230 } 231 232 /* 233 * fls: find last (most-significant) bit set. 234 * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32. 235 */ 236 static __inline__ int fls(unsigned int x) 237 { 238 int lz; 239 240 asm ("cntlzw %0,%1" : "=r" (lz) : "r" (x)); 241 return 32 - lz; 242 } 243 244 static __inline__ unsigned long __fls(unsigned long x) 245 { 246 return __ilog2(x); 247 } 248 249 /* 250 * 64-bit can do this using one cntlzd (count leading zeroes doubleword) 251 * instruction; for 32-bit we use the generic version, which does two 252 * 32-bit fls calls. 253 */ 254 #ifdef __powerpc64__ 255 static __inline__ int fls64(__u64 x) 256 { 257 int lz; 258 259 asm ("cntlzd %0,%1" : "=r" (lz) : "r" (x)); 260 return 64 - lz; 261 } 262 #else 263 #include <asm-generic/bitops/fls64.h> 264 #endif /* __powerpc64__ */ 265 266 #include <asm-generic/bitops/hweight.h> 267 #include <asm-generic/bitops/find.h> 268 269 /* Little-endian versions */ 270 271 static __inline__ int test_le_bit(unsigned long nr, 272 __const__ unsigned long *addr) 273 { 274 __const__ unsigned char *tmp = (__const__ unsigned char *) addr; 275 return (tmp[nr >> 3] >> (nr & 7)) & 1; 276 } 277 278 #define __set_le_bit(nr, addr) \ 279 __set_bit((nr) ^ BITOP_LE_SWIZZLE, (addr)) 280 #define __clear_le_bit(nr, addr) \ 281 __clear_bit((nr) ^ BITOP_LE_SWIZZLE, (addr)) 282 283 #define test_and_set_le_bit(nr, addr) \ 284 test_and_set_bit((nr) ^ BITOP_LE_SWIZZLE, (addr)) 285 #define test_and_clear_le_bit(nr, addr) \ 286 test_and_clear_bit((nr) ^ BITOP_LE_SWIZZLE, (addr)) 287 288 #define __test_and_set_le_bit(nr, addr) \ 289 __test_and_set_bit((nr) ^ BITOP_LE_SWIZZLE, (addr)) 290 #define __test_and_clear_le_bit(nr, addr) \ 291 __test_and_clear_bit((nr) ^ BITOP_LE_SWIZZLE, (addr)) 292 293 #define find_first_zero_le_bit(addr, size) generic_find_next_zero_le_bit((addr), (size), 0) 294 unsigned long generic_find_next_zero_le_bit(const unsigned long *addr, 295 unsigned long size, unsigned long offset); 296 297 unsigned long generic_find_next_le_bit(const unsigned long *addr, 298 unsigned long size, unsigned long offset); 299 /* Bitmap functions for the ext2 filesystem */ 300 301 #define ext2_set_bit(nr,addr) \ 302 __test_and_set_le_bit((nr), (unsigned long*)addr) 303 #define ext2_clear_bit(nr, addr) \ 304 __test_and_clear_le_bit((nr), (unsigned long*)addr) 305 306 #define ext2_set_bit_atomic(lock, nr, addr) \ 307 test_and_set_le_bit((nr), (unsigned long*)addr) 308 #define ext2_clear_bit_atomic(lock, nr, addr) \ 309 test_and_clear_le_bit((nr), (unsigned long*)addr) 310 311 #define ext2_test_bit(nr, addr) test_le_bit((nr),(unsigned long*)addr) 312 313 #define ext2_find_first_zero_bit(addr, size) \ 314 find_first_zero_le_bit((unsigned long*)addr, size) 315 #define ext2_find_next_zero_bit(addr, size, off) \ 316 generic_find_next_zero_le_bit((unsigned long*)addr, size, off) 317 318 #define ext2_find_next_bit(addr, size, off) \ 319 generic_find_next_le_bit((unsigned long *)addr, size, off) 320 /* Bitmap functions for the minix filesystem. */ 321 322 #define minix_test_and_set_bit(nr,addr) \ 323 __test_and_set_le_bit(nr, (unsigned long *)addr) 324 #define minix_set_bit(nr,addr) \ 325 __set_le_bit(nr, (unsigned long *)addr) 326 #define minix_test_and_clear_bit(nr,addr) \ 327 __test_and_clear_le_bit(nr, (unsigned long *)addr) 328 #define minix_test_bit(nr,addr) \ 329 test_le_bit(nr, (unsigned long *)addr) 330 331 #define minix_find_first_zero_bit(addr,size) \ 332 find_first_zero_le_bit((unsigned long *)addr, size) 333 334 #include <asm-generic/bitops/sched.h> 335 336 #endif /* __KERNEL__ */ 337 338 #endif /* _ASM_POWERPC_BITOPS_H */ 339