/*
 * PowerPC atomic bit operations.
 *
 * Merged version by David Gibson <david@gibson.dropbear.id.au>.
 * Based on ppc64 versions by: Dave Engebretsen, Todd Inglett, Don
 * Reed, Pat McCarthy, Peter Bergner, Anton Blanchard.  They
 * originally took it from the ppc32 code.
 *
 * Within a word, bits are numbered LSB first.  Lot's of places make
 * this assumption by directly testing bits with (val & (1<<nr)).
 * This can cause confusion for large (> 1 word) bitmaps on a
 * big-endian system because, unlike little endian, the number of each
 * bit depends on the word size.
 *
 * The bitop functions are defined to work on unsigned longs, so for a
 * ppc64 system the bits end up numbered:
 *   |63..............0|127............64|191...........128|255...........196|
 * and on ppc32:
 *   |31.....0|63....31|95....64|127...96|159..128|191..160|223..192|255..224|
 *
 * There are a few little-endian macros used mostly for filesystem
 * bitmaps, these work on similar bit arrays layouts, but
 * byte-oriented:
 *   |7...0|15...8|23...16|31...24|39...32|47...40|55...48|63...56|
 *
 * The main difference is that bit 3-5 (64b) or 3-4 (32b) in the bit
 * number field needs to be reversed compared to the big-endian bit
 * fields. This can be achieved by XOR with 0x38 (64b) or 0x18 (32b).
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#ifndef _ASM_POWERPC_BITOPS_H
#define _ASM_POWERPC_BITOPS_H

#ifdef __KERNEL__

#ifndef _LINUX_BITOPS_H
#error only <linux/bitops.h> can be included directly
#endif

#include <linux/compiler.h>
#include <asm/asm-compat.h>
#include <asm/synch.h>

/* PPC bit number conversion */
#define PPC_BITLSHIFT(be)       (BITS_PER_LONG - 1 - (be))
#define PPC_BIT(bit)            (1UL << PPC_BITLSHIFT(bit))
#define PPC_BITMASK(bs, be)     ((PPC_BIT(bs) - PPC_BIT(be)) | PPC_BIT(bs))

/*
 * clear_bit doesn't imply a memory barrier
 */
#define smp_mb__before_clear_bit()      smp_mb()
#define smp_mb__after_clear_bit()       smp_mb()

/* Macro for generating the ***_bits() functions */
#define DEFINE_BITOP(fn, op, prefix)            \
static __inline__ void fn(unsigned long mask,   \
                volatile unsigned long *_p)     \
{                                               \
        unsigned long old;                      \
        unsigned long *p = (unsigned long *)_p; \
        __asm__ __volatile__ (                  \
        prefix                                  \
"1:"    PPC_LLARX(%0,0,%3,0) "\n"               \
        stringify_in_c(op) "%0,%0,%2\n"         \
        PPC405_ERR77(0,%3)                      \
        PPC_STLCX "%0,0,%3\n"                   \
        "bne- 1b\n"                             \
        : "=&r" (old), "+m" (*p)                \
        : "r" (mask), "r" (p)                   \
        : "cc", "memory");                      \
}

DEFINE_BITOP(set_bits, or, "")
DEFINE_BITOP(clear_bits, andc, "")
DEFINE_BITOP(clear_bits_unlock, andc, PPC_RELEASE_BARRIER)
DEFINE_BITOP(change_bits, xor, "")

static __inline__ void set_bit(int nr, volatile unsigned long *addr)
{
        set_bits(BIT_MASK(nr), addr + BIT_WORD(nr));
}

static __inline__ void clear_bit(int nr, volatile unsigned long *addr)
{
        clear_bits(BIT_MASK(nr), addr + BIT_WORD(nr));
}

static __inline__ void clear_bit_unlock(int nr, volatile unsigned long *addr)
{
        clear_bits_unlock(BIT_MASK(nr), addr + BIT_WORD(nr));
}

static __inline__ void change_bit(int nr, volatile unsigned long *addr)
{
        change_bits(BIT_MASK(nr), addr + BIT_WORD(nr));
}

/* Like DEFINE_BITOP(), with changes to the arguments to 'op' and the output
 * operands. */
#define DEFINE_TESTOP(fn, op, prefix, postfix, eh)      \
static __inline__ unsigned long fn(                     \
                unsigned long mask,                     \
                volatile unsigned long *_p)             \
{                                                       \
        unsigned long old, t;                           \
        unsigned long *p = (unsigned long *)_p;         \
        __asm__ __volatile__ (                          \
        prefix                                          \
"1:"    PPC_LLARX(%0,0,%3,eh) "\n"                      \
        stringify_in_c(op) "%1,%0,%2\n"                 \
        PPC405_ERR77(0,%3)                              \
        PPC_STLCX "%1,0,%3\n"                           \
        "bne- 1b\n"                                     \
        postfix                                         \
        : "=&r" (old), "=&r" (t)                        \
        : "r" (mask), "r" (p)                           \
        : "cc", "memory");                              \
        return (old & mask);                            \
}

DEFINE_TESTOP(test_and_set_bits, or, PPC_ATOMIC_ENTRY_BARRIER,
              PPC_ATOMIC_EXIT_BARRIER, 0)
DEFINE_TESTOP(test_and_set_bits_lock, or, "",
              PPC_ACQUIRE_BARRIER, 1)
DEFINE_TESTOP(test_and_clear_bits, andc, PPC_ATOMIC_ENTRY_BARRIER,
              PPC_ATOMIC_EXIT_BARRIER, 0)
DEFINE_TESTOP(test_and_change_bits, xor, PPC_ATOMIC_ENTRY_BARRIER,
              PPC_ATOMIC_EXIT_BARRIER, 0)

static __inline__ int test_and_set_bit(unsigned long nr,
                                       volatile unsigned long *addr)
{
        return test_and_set_bits(BIT_MASK(nr), addr + BIT_WORD(nr)) != 0;
}

static __inline__ int test_and_set_bit_lock(unsigned long nr,
                                       volatile unsigned long *addr)
{
        return test_and_set_bits_lock(BIT_MASK(nr),
                                addr + BIT_WORD(nr)) != 0;
}

static __inline__ int test_and_clear_bit(unsigned long nr,
                                         volatile unsigned long *addr)
{
        return test_and_clear_bits(BIT_MASK(nr), addr + BIT_WORD(nr)) != 0;
}

static __inline__ int test_and_change_bit(unsigned long nr,
                                          volatile unsigned long *addr)
{
        return test_and_change_bits(BIT_MASK(nr), addr + BIT_WORD(nr)) != 0;
}

#include <asm-generic/bitops/non-atomic.h>

static __inline__ void __clear_bit_unlock(int nr, volatile unsigned long *addr)
{
        __asm__ __volatile__(PPC_RELEASE_BARRIER "" ::: "memory");
        __clear_bit(nr, addr);
}

/*
 * Return the zero-based bit position (LE, not IBM bit numbering) of
 * the most significant 1-bit in a double word.
 */
static __inline__ __attribute__((const))
int __ilog2(unsigned long x)
{
        int lz;

        asm (PPC_CNTLZL "%0,%1" : "=r" (lz) : "r" (x));
        return BITS_PER_LONG - 1 - lz;
}

static inline __attribute__((const))
int __ilog2_u32(u32 n)
{
        int bit;
        asm ("cntlzw %0,%1" : "=r" (bit) : "r" (n));
        return 31 - bit;
}

#ifdef __powerpc64__
static inline __attribute__((const))
int __ilog2_u64(u64 n)
{
        int bit;
        asm ("cntlzd %0,%1" : "=r" (bit) : "r" (n));
        return 63 - bit;
}
#endif

/*
 * Determines the bit position of the least significant 0 bit in the
 * specified double word. The returned bit position will be
 * zero-based, starting from the right side (63/31 - 0).
 */
static __inline__ unsigned long ffz(unsigned long x)
{
        /* no zero exists anywhere in the 8 byte area. */
        if ((x = ~x) == 0)
                return BITS_PER_LONG;

        /*
         * Calculate the bit position of the least significant '1' bit in x
         * (since x has been changed this will actually be the least significant
         * '0' bit in * the original x).  Note: (x & -x) gives us a mask that
         * is the least significant * (RIGHT-most) 1-bit of the value in x.
         */
        return __ilog2(x & -x);
}

static __inline__ int __ffs(unsigned long x)
{
        return __ilog2(x & -x);
}

/*
 * ffs: find first bit set. This is defined the same way as
 * the libc and compiler builtin ffs routines, therefore
 * differs in spirit from the above ffz (man ffs).
 */
static __inline__ int ffs(int x)
{
        unsigned long i = (unsigned long)x;
        return __ilog2(i & -i) + 1;
}

/*
 * fls: find last (most-significant) bit set.
 * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
 */
static __inline__ int fls(unsigned int x)
{
        int lz;

        asm ("cntlzw %0,%1" : "=r" (lz) : "r" (x));
        return 32 - lz;
}

static __inline__ unsigned long __fls(unsigned long x)
{
        return __ilog2(x);
}

/*
 * 64-bit can do this using one cntlzd (count leading zeroes doubleword)
 * instruction; for 32-bit we use the generic version, which does two
 * 32-bit fls calls.
 */
#ifdef __powerpc64__
static __inline__ int fls64(__u64 x)
{
        int lz;

        asm ("cntlzd %0,%1" : "=r" (lz) : "r" (x));
        return 64 - lz;
}
#else
#include <asm-generic/bitops/fls64.h>
#endif /* __powerpc64__ */

#ifdef CONFIG_PPC64
unsigned int __arch_hweight8(unsigned int w);
unsigned int __arch_hweight16(unsigned int w);
unsigned int __arch_hweight32(unsigned int w);
unsigned long __arch_hweight64(__u64 w);
#include <asm-generic/bitops/const_hweight.h>
#else
#include <asm-generic/bitops/hweight.h>
#endif

#include <asm-generic/bitops/find.h>

/* Little-endian versions */
#include <asm-generic/bitops/le.h>

/* Bitmap functions for the ext2 filesystem */

#include <asm-generic/bitops/ext2-atomic-setbit.h>

#include <asm-generic/bitops/sched.h>

#endif /* __KERNEL__ */

#endif /* _ASM_POWERPC_BITOPS_H */