summaryrefslogtreecommitdiffstats
path: root/arch/arm/include/asm/bitops.h
diff options
context:
space:
mode:
Diffstat (limited to 'arch/arm/include/asm/bitops.h')
-rw-r--r--arch/arm/include/asm/bitops.h340
1 files changed, 340 insertions, 0 deletions
diff --git a/arch/arm/include/asm/bitops.h b/arch/arm/include/asm/bitops.h
new file mode 100644
index 0000000..9a1db20
--- /dev/null
+++ b/arch/arm/include/asm/bitops.h
@@ -0,0 +1,340 @@
+/*
+ * Copyright 1995, Russell King.
+ * Various bits and pieces copyrights include:
+ * Linus Torvalds (test_bit).
+ * Big endian support: Copyright 2001, Nicolas Pitre
+ * reworked by rmk.
+ *
+ * bit 0 is the LSB of an "unsigned long" quantity.
+ *
+ * Please note that the code in this file should never be included
+ * from user space. Many of these are not implemented in assembler
+ * since they would be too costly. Also, they require privileged
+ * instructions (which are not available from user mode) to ensure
+ * that they are atomic.
+ */
+
+#ifndef __ASM_ARM_BITOPS_H
+#define __ASM_ARM_BITOPS_H
+
+#ifdef __KERNEL__
+
+#ifndef _LINUX_BITOPS_H
+#error only <linux/bitops.h> can be included directly
+#endif
+
+#include <linux/compiler.h>
+#include <asm/system.h>
+
+#define smp_mb__before_clear_bit() mb()
+#define smp_mb__after_clear_bit() mb()
+
+/*
+ * These functions are the basis of our bit ops.
+ *
+ * First, the atomic bitops. These use native endian.
+ */
+static inline void ____atomic_set_bit(unsigned int bit, volatile unsigned long *p)
+{
+ unsigned long flags;
+ unsigned long mask = 1UL << (bit & 31);
+
+ p += bit >> 5;
+
+ raw_local_irq_save(flags);
+ *p |= mask;
+ raw_local_irq_restore(flags);
+}
+
+static inline void ____atomic_clear_bit(unsigned int bit, volatile unsigned long *p)
+{
+ unsigned long flags;
+ unsigned long mask = 1UL << (bit & 31);
+
+ p += bit >> 5;
+
+ raw_local_irq_save(flags);
+ *p &= ~mask;
+ raw_local_irq_restore(flags);
+}
+
+static inline void ____atomic_change_bit(unsigned int bit, volatile unsigned long *p)
+{
+ unsigned long flags;
+ unsigned long mask = 1UL << (bit & 31);
+
+ p += bit >> 5;
+
+ raw_local_irq_save(flags);
+ *p ^= mask;
+ raw_local_irq_restore(flags);
+}
+
+static inline int
+____atomic_test_and_set_bit(unsigned int bit, volatile unsigned long *p)
+{
+ unsigned long flags;
+ unsigned int res;
+ unsigned long mask = 1UL << (bit & 31);
+
+ p += bit >> 5;
+
+ raw_local_irq_save(flags);
+ res = *p;
+ *p = res | mask;
+ raw_local_irq_restore(flags);
+
+ return res & mask;
+}
+
+static inline int
+____atomic_test_and_clear_bit(unsigned int bit, volatile unsigned long *p)
+{
+ unsigned long flags;
+ unsigned int res;
+ unsigned long mask = 1UL << (bit & 31);
+
+ p += bit >> 5;
+
+ raw_local_irq_save(flags);
+ res = *p;
+ *p = res & ~mask;
+ raw_local_irq_restore(flags);
+
+ return res & mask;
+}
+
+static inline int
+____atomic_test_and_change_bit(unsigned int bit, volatile unsigned long *p)
+{
+ unsigned long flags;
+ unsigned int res;
+ unsigned long mask = 1UL << (bit & 31);
+
+ p += bit >> 5;
+
+ raw_local_irq_save(flags);
+ res = *p;
+ *p = res ^ mask;
+ raw_local_irq_restore(flags);
+
+ return res & mask;
+}
+
+#include <asm-generic/bitops/non-atomic.h>
+
+/*
+ * A note about Endian-ness.
+ * -------------------------
+ *
+ * When the ARM is put into big endian mode via CR15, the processor
+ * merely swaps the order of bytes within words, thus:
+ *
+ * ------------ physical data bus bits -----------
+ * D31 ... D24 D23 ... D16 D15 ... D8 D7 ... D0
+ * little byte 3 byte 2 byte 1 byte 0
+ * big byte 0 byte 1 byte 2 byte 3
+ *
+ * This means that reading a 32-bit word at address 0 returns the same
+ * value irrespective of the endian mode bit.
+ *
+ * Peripheral devices should be connected with the data bus reversed in
+ * "Big Endian" mode. ARM Application Note 61 is applicable, and is
+ * available from http://www.arm.com/.
+ *
+ * The following assumes that the data bus connectivity for big endian
+ * mode has been followed.
+ *
+ * Note that bit 0 is defined to be 32-bit word bit 0, not byte 0 bit 0.
+ */
+
+/*
+ * Little endian assembly bitops. nr = 0 -> byte 0 bit 0.
+ */
+extern void _set_bit_le(int nr, volatile unsigned long * p);
+extern void _clear_bit_le(int nr, volatile unsigned long * p);
+extern void _change_bit_le(int nr, volatile unsigned long * p);
+extern int _test_and_set_bit_le(int nr, volatile unsigned long * p);
+extern int _test_and_clear_bit_le(int nr, volatile unsigned long * p);
+extern int _test_and_change_bit_le(int nr, volatile unsigned long * p);
+extern int _find_first_zero_bit_le(const void * p, unsigned size);
+extern int _find_next_zero_bit_le(const void * p, int size, int offset);
+extern int _find_first_bit_le(const unsigned long *p, unsigned size);
+extern int _find_next_bit_le(const unsigned long *p, int size, int offset);
+
+/*
+ * Big endian assembly bitops. nr = 0 -> byte 3 bit 0.
+ */
+extern void _set_bit_be(int nr, volatile unsigned long * p);
+extern void _clear_bit_be(int nr, volatile unsigned long * p);
+extern void _change_bit_be(int nr, volatile unsigned long * p);
+extern int _test_and_set_bit_be(int nr, volatile unsigned long * p);
+extern int _test_and_clear_bit_be(int nr, volatile unsigned long * p);
+extern int _test_and_change_bit_be(int nr, volatile unsigned long * p);
+extern int _find_first_zero_bit_be(const void * p, unsigned size);
+extern int _find_next_zero_bit_be(const void * p, int size, int offset);
+extern int _find_first_bit_be(const unsigned long *p, unsigned size);
+extern int _find_next_bit_be(const unsigned long *p, int size, int offset);
+
+#ifndef CONFIG_SMP
+/*
+ * The __* form of bitops are non-atomic and may be reordered.
+ */
+#define ATOMIC_BITOP_LE(name,nr,p) \
+ (__builtin_constant_p(nr) ? \
+ ____atomic_##name(nr, p) : \
+ _##name##_le(nr,p))
+
+#define ATOMIC_BITOP_BE(name,nr,p) \
+ (__builtin_constant_p(nr) ? \
+ ____atomic_##name(nr, p) : \
+ _##name##_be(nr,p))
+#else
+#define ATOMIC_BITOP_LE(name,nr,p) _##name##_le(nr,p)
+#define ATOMIC_BITOP_BE(name,nr,p) _##name##_be(nr,p)
+#endif
+
+#define NONATOMIC_BITOP(name,nr,p) \
+ (____nonatomic_##name(nr, p))
+
+#ifndef __ARMEB__
+/*
+ * These are the little endian, atomic definitions.
+ */
+#define set_bit(nr,p) ATOMIC_BITOP_LE(set_bit,nr,p)
+#define clear_bit(nr,p) ATOMIC_BITOP_LE(clear_bit,nr,p)
+#define change_bit(nr,p) ATOMIC_BITOP_LE(change_bit,nr,p)
+#define test_and_set_bit(nr,p) ATOMIC_BITOP_LE(test_and_set_bit,nr,p)
+#define test_and_clear_bit(nr,p) ATOMIC_BITOP_LE(test_and_clear_bit,nr,p)
+#define test_and_change_bit(nr,p) ATOMIC_BITOP_LE(test_and_change_bit,nr,p)
+#define find_first_zero_bit(p,sz) _find_first_zero_bit_le(p,sz)
+#define find_next_zero_bit(p,sz,off) _find_next_zero_bit_le(p,sz,off)
+#define find_first_bit(p,sz) _find_first_bit_le(p,sz)
+#define find_next_bit(p,sz,off) _find_next_bit_le(p,sz,off)
+
+#define WORD_BITOFF_TO_LE(x) ((x))
+
+#else
+
+/*
+ * These are the big endian, atomic definitions.
+ */
+#define set_bit(nr,p) ATOMIC_BITOP_BE(set_bit,nr,p)
+#define clear_bit(nr,p) ATOMIC_BITOP_BE(clear_bit,nr,p)
+#define change_bit(nr,p) ATOMIC_BITOP_BE(change_bit,nr,p)
+#define test_and_set_bit(nr,p) ATOMIC_BITOP_BE(test_and_set_bit,nr,p)
+#define test_and_clear_bit(nr,p) ATOMIC_BITOP_BE(test_and_clear_bit,nr,p)
+#define test_and_change_bit(nr,p) ATOMIC_BITOP_BE(test_and_change_bit,nr,p)
+#define find_first_zero_bit(p,sz) _find_first_zero_bit_be(p,sz)
+#define find_next_zero_bit(p,sz,off) _find_next_zero_bit_be(p,sz,off)
+#define find_first_bit(p,sz) _find_first_bit_be(p,sz)
+#define find_next_bit(p,sz,off) _find_next_bit_be(p,sz,off)
+
+#define WORD_BITOFF_TO_LE(x) ((x) ^ 0x18)
+
+#endif
+
+#if __LINUX_ARM_ARCH__ < 5
+
+#include <asm-generic/bitops/ffz.h>
+#include <asm-generic/bitops/__ffs.h>
+#include <asm-generic/bitops/fls.h>
+#include <asm-generic/bitops/ffs.h>
+
+#else
+
+static inline int constant_fls(int x)
+{
+ int r = 32;
+
+ if (!x)
+ return 0;
+ if (!(x & 0xffff0000u)) {
+ x <<= 16;
+ r -= 16;
+ }
+ if (!(x & 0xff000000u)) {
+ x <<= 8;
+ r -= 8;
+ }
+ if (!(x & 0xf0000000u)) {
+ x <<= 4;
+ r -= 4;
+ }
+ if (!(x & 0xc0000000u)) {
+ x <<= 2;
+ r -= 2;
+ }
+ if (!(x & 0x80000000u)) {
+ x <<= 1;
+ r -= 1;
+ }
+ return r;
+}
+
+/*
+ * On ARMv5 and above those functions can be implemented around
+ * the clz instruction for much better code efficiency.
+ */
+
+#define __fls(x) \
+ ( __builtin_constant_p(x) ? constant_fls(x) : \
+ ({ int __r; asm("clz\t%0, %1" : "=r"(__r) : "r"(x) : "cc"); 32-__r; }) )
+
+/* Implement fls() in C so that 64-bit args are suitably truncated */
+static inline int fls(int x)
+{
+ return __fls(x);
+}
+
+#define ffs(x) ({ unsigned long __t = (x); fls(__t & -__t); })
+#define __ffs(x) (ffs(x) - 1)
+#define ffz(x) __ffs( ~(x) )
+
+#endif
+
+#include <asm-generic/bitops/fls64.h>
+
+#include <asm-generic/bitops/sched.h>
+#include <asm-generic/bitops/hweight.h>
+#include <asm-generic/bitops/lock.h>
+
+/*
+ * Ext2 is defined to use little-endian byte ordering.
+ * These do not need to be atomic.
+ */
+#define ext2_set_bit(nr,p) \
+ __test_and_set_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
+#define ext2_set_bit_atomic(lock,nr,p) \
+ test_and_set_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
+#define ext2_clear_bit(nr,p) \
+ __test_and_clear_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
+#define ext2_clear_bit_atomic(lock,nr,p) \
+ test_and_clear_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
+#define ext2_test_bit(nr,p) \
+ test_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
+#define ext2_find_first_zero_bit(p,sz) \
+ _find_first_zero_bit_le(p,sz)
+#define ext2_find_next_zero_bit(p,sz,off) \
+ _find_next_zero_bit_le(p,sz,off)
+#define ext2_find_next_bit(p, sz, off) \
+ _find_next_bit_le(p, sz, off)
+
+/*
+ * Minix is defined to use little-endian byte ordering.
+ * These do not need to be atomic.
+ */
+#define minix_set_bit(nr,p) \
+ __set_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
+#define minix_test_bit(nr,p) \
+ test_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
+#define minix_test_and_set_bit(nr,p) \
+ __test_and_set_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
+#define minix_test_and_clear_bit(nr,p) \
+ __test_and_clear_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
+#define minix_find_first_zero_bit(p,sz) \
+ _find_first_zero_bit_le(p,sz)
+
+#endif /* __KERNEL__ */
+
+#endif /* _ARM_BITOPS_H */
OpenPOWER on IntegriCloud