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_LE_SWIZZLE ((BITS_PER_LONG-1) & ~0x7) 56 57 /* Macro for generating the ***_bits() functions */ 58 #define DEFINE_BITOP(fn, op, prefix, postfix) \ 59 static __inline__ void fn(unsigned long mask, \ 60 volatile unsigned long *_p) \ 61 { \ 62 unsigned long old; \ 63 unsigned long *p = (unsigned long *)_p; \ 64 __asm__ __volatile__ ( \ 65 prefix \ 66 "1:" PPC_LLARX(%0,0,%3,0) "\n" \ 67 stringify_in_c(op) "%0,%0,%2\n" \ 68 PPC405_ERR77(0,%3) \ 69 PPC_STLCX "%0,0,%3\n" \ 70 "bne- 1b\n" \ 71 postfix \ 72 : "=&r" (old), "+m" (*p) \ 73 : "r" (mask), "r" (p) \ 74 : "cc", "memory"); \ 75 } 76 77 DEFINE_BITOP(set_bits, or, "", "") 78 DEFINE_BITOP(clear_bits, andc, "", "") 79 DEFINE_BITOP(clear_bits_unlock, andc, PPC_RELEASE_BARRIER, "") 80 DEFINE_BITOP(change_bits, xor, "", "") 81 82 static __inline__ void set_bit(int nr, volatile unsigned long *addr) 83 { 84 set_bits(BIT_MASK(nr), addr + BIT_WORD(nr)); 85 } 86 87 static __inline__ void clear_bit(int nr, volatile unsigned long *addr) 88 { 89 clear_bits(BIT_MASK(nr), addr + BIT_WORD(nr)); 90 } 91 92 static __inline__ void clear_bit_unlock(int nr, volatile unsigned long *addr) 93 { 94 clear_bits_unlock(BIT_MASK(nr), addr + BIT_WORD(nr)); 95 } 96 97 static __inline__ void change_bit(int nr, volatile unsigned long *addr) 98 { 99 change_bits(BIT_MASK(nr), addr + BIT_WORD(nr)); 100 } 101 102 /* Like DEFINE_BITOP(), with changes to the arguments to 'op' and the output 103 * operands. */ 104 #define DEFINE_TESTOP(fn, op, prefix, postfix, eh) \ 105 static __inline__ unsigned long fn( \ 106 unsigned long mask, \ 107 volatile unsigned long *_p) \ 108 { \ 109 unsigned long old, t; \ 110 unsigned long *p = (unsigned long *)_p; \ 111 __asm__ __volatile__ ( \ 112 prefix \ 113 "1:" PPC_LLARX(%0,0,%3,eh) "\n" \ 114 stringify_in_c(op) "%1,%0,%2\n" \ 115 PPC405_ERR77(0,%3) \ 116 PPC_STLCX "%1,0,%3\n" \ 117 "bne- 1b\n" \ 118 postfix \ 119 : "=&r" (old), "=&r" (t) \ 120 : "r" (mask), "r" (p) \ 121 : "cc", "memory"); \ 122 return (old & mask); \ 123 } 124 125 DEFINE_TESTOP(test_and_set_bits, or, PPC_ATOMIC_ENTRY_BARRIER, 126 PPC_ATOMIC_EXIT_BARRIER, 0) 127 DEFINE_TESTOP(test_and_set_bits_lock, or, "", 128 PPC_ACQUIRE_BARRIER, 1) 129 DEFINE_TESTOP(test_and_clear_bits, andc, PPC_ATOMIC_ENTRY_BARRIER, 130 PPC_ATOMIC_EXIT_BARRIER, 0) 131 DEFINE_TESTOP(test_and_change_bits, xor, PPC_ATOMIC_ENTRY_BARRIER, 132 PPC_ATOMIC_EXIT_BARRIER, 0) 133 134 static __inline__ int test_and_set_bit(unsigned long nr, 135 volatile unsigned long *addr) 136 { 137 return test_and_set_bits(BIT_MASK(nr), addr + BIT_WORD(nr)) != 0; 138 } 139 140 static __inline__ int test_and_set_bit_lock(unsigned long nr, 141 volatile unsigned long *addr) 142 { 143 return test_and_set_bits_lock(BIT_MASK(nr), 144 addr + BIT_WORD(nr)) != 0; 145 } 146 147 static __inline__ int test_and_clear_bit(unsigned long nr, 148 volatile unsigned long *addr) 149 { 150 return test_and_clear_bits(BIT_MASK(nr), addr + BIT_WORD(nr)) != 0; 151 } 152 153 static __inline__ int test_and_change_bit(unsigned long nr, 154 volatile unsigned long *addr) 155 { 156 return test_and_change_bits(BIT_MASK(nr), addr + BIT_WORD(nr)) != 0; 157 } 158 159 #include <asm-generic/bitops/non-atomic.h> 160 161 static __inline__ void __clear_bit_unlock(int nr, volatile unsigned long *addr) 162 { 163 __asm__ __volatile__(PPC_RELEASE_BARRIER "" ::: "memory"); 164 __clear_bit(nr, addr); 165 } 166 167 /* 168 * Return the zero-based bit position (LE, not IBM bit numbering) of 169 * the most significant 1-bit in a double word. 170 */ 171 static __inline__ __attribute__((const)) 172 int __ilog2(unsigned long x) 173 { 174 int lz; 175 176 asm (PPC_CNTLZL "%0,%1" : "=r" (lz) : "r" (x)); 177 return BITS_PER_LONG - 1 - lz; 178 } 179 180 static inline __attribute__((const)) 181 int __ilog2_u32(u32 n) 182 { 183 int bit; 184 asm ("cntlzw %0,%1" : "=r" (bit) : "r" (n)); 185 return 31 - bit; 186 } 187 188 #ifdef __powerpc64__ 189 static inline __attribute__((const)) 190 int __ilog2_u64(u64 n) 191 { 192 int bit; 193 asm ("cntlzd %0,%1" : "=r" (bit) : "r" (n)); 194 return 63 - bit; 195 } 196 #endif 197 198 /* 199 * Determines the bit position of the least significant 0 bit in the 200 * specified double word. The returned bit position will be 201 * zero-based, starting from the right side (63/31 - 0). 202 */ 203 static __inline__ unsigned long ffz(unsigned long x) 204 { 205 /* no zero exists anywhere in the 8 byte area. */ 206 if ((x = ~x) == 0) 207 return BITS_PER_LONG; 208 209 /* 210 * Calculate the bit position of the least significant '1' bit in x 211 * (since x has been changed this will actually be the least significant 212 * '0' bit in * the original x). Note: (x & -x) gives us a mask that 213 * is the least significant * (RIGHT-most) 1-bit of the value in x. 214 */ 215 return __ilog2(x & -x); 216 } 217 218 static __inline__ int __ffs(unsigned long x) 219 { 220 return __ilog2(x & -x); 221 } 222 223 /* 224 * ffs: find first bit set. This is defined the same way as 225 * the libc and compiler builtin ffs routines, therefore 226 * differs in spirit from the above ffz (man ffs). 227 */ 228 static __inline__ int ffs(int x) 229 { 230 unsigned long i = (unsigned long)x; 231 return __ilog2(i & -i) + 1; 232 } 233 234 /* 235 * fls: find last (most-significant) bit set. 236 * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32. 237 */ 238 static __inline__ int fls(unsigned int x) 239 { 240 int lz; 241 242 asm ("cntlzw %0,%1" : "=r" (lz) : "r" (x)); 243 return 32 - lz; 244 } 245 246 static __inline__ unsigned long __fls(unsigned long x) 247 { 248 return __ilog2(x); 249 } 250 251 /* 252 * 64-bit can do this using one cntlzd (count leading zeroes doubleword) 253 * instruction; for 32-bit we use the generic version, which does two 254 * 32-bit fls calls. 255 */ 256 #ifdef __powerpc64__ 257 static __inline__ int fls64(__u64 x) 258 { 259 int lz; 260 261 asm ("cntlzd %0,%1" : "=r" (lz) : "r" (x)); 262 return 64 - lz; 263 } 264 #else 265 #include <asm-generic/bitops/fls64.h> 266 #endif /* __powerpc64__ */ 267 268 #ifdef CONFIG_PPC64 269 unsigned int __arch_hweight8(unsigned int w); 270 unsigned int __arch_hweight16(unsigned int w); 271 unsigned int __arch_hweight32(unsigned int w); 272 unsigned long __arch_hweight64(__u64 w); 273 #include <asm-generic/bitops/const_hweight.h> 274 #else 275 #include <asm-generic/bitops/hweight.h> 276 #endif 277 278 #include <asm-generic/bitops/find.h> 279 280 /* Little-endian versions */ 281 #include <asm-generic/bitops/le.h> 282 283 /* Bitmap functions for the ext2 filesystem */ 284 285 #include <asm-generic/bitops/ext2-atomic-setbit.h> 286 287 #include <asm-generic/bitops/sched.h> 288 289 #endif /* __KERNEL__ */ 290 291 #endif /* _ASM_POWERPC_BITOPS_H */ 292