[U-Boot] [PATCH 3/4] nios2: use bitops from linux-2.6 asm-generic

[Scott McNutt]

Applied.
Thank you,
--Scott

Thomas Chou wrote:
> These are needed to use ubi/ubifs.
> 
> Signed-off-by: Thomas Chou <thomas at wytron.com.tw>
> ---
>  include/asm-nios2/bitops.h            |   14 +--
>  include/asm-nios2/bitops/atomic.h     |  189 +++++++++++++++++++++++++++++++++
>  include/asm-nios2/bitops/ffs.h        |   41 +++++++
>  include/asm-nios2/bitops/non-atomic.h |  108 +++++++++++++++++++
>  4 files changed, 342 insertions(+), 10 deletions(-)
>  create mode 100644 include/asm-nios2/bitops/atomic.h
>  create mode 100644 include/asm-nios2/bitops/ffs.h
>  create mode 100644 include/asm-nios2/bitops/non-atomic.h
> 
> diff --git a/include/asm-nios2/bitops.h b/include/asm-nios2/bitops.h
> index 5776bda..cf48ff7 100644
> --- a/include/asm-nios2/bitops.h
> +++ b/include/asm-nios2/bitops.h
> @@ -24,15 +24,9 @@
>  #ifndef __ASM_NIOS2_BITOPS_H_
>  #define __ASM_NIOS2_BITOPS_H_
>  
> -
> -extern void set_bit(int nr, volatile void * a);
> -extern void clear_bit(int nr, volatile void * a);
> -extern int test_and_clear_bit(int nr, volatile void * a);
> -extern void change_bit(unsigned long nr, volatile void *addr);
> -extern int test_and_set_bit(int nr, volatile void * a);
> -extern int test_and_change_bit(int nr, volatile void * addr);
> -extern int test_bit(int nr, volatile void * a);
> -extern int ffs(int i);
> -#define PLATFORM_FFS
> +/* copied from linux-2.6/include/asm-generic/bitops */
> +#include <asm/bitops/atomic.h>
> +#include <asm/bitops/non-atomic.h>
> +#include <asm/bitops/ffs.h>
>  
>  #endif /* __ASM_NIOS2_BITOPS_H */
> diff --git a/include/asm-nios2/bitops/atomic.h b/include/asm-nios2/bitops/atomic.h
> new file mode 100644
> index 0000000..c894646
> --- /dev/null
> +++ b/include/asm-nios2/bitops/atomic.h
> @@ -0,0 +1,189 @@
> +#ifndef _ASM_GENERIC_BITOPS_ATOMIC_H_
> +#define _ASM_GENERIC_BITOPS_ATOMIC_H_
> +
> +#include <asm/types.h>
> +#include <asm/system.h>
> +
> +#ifdef CONFIG_SMP
> +#include <asm/spinlock.h>
> +#include <asm/cache.h>		/* we use L1_CACHE_BYTES */
> +
> +/* Use an array of spinlocks for our atomic_ts.
> + * Hash function to index into a different SPINLOCK.
> + * Since "a" is usually an address, use one spinlock per cacheline.
> + */
> +#  define ATOMIC_HASH_SIZE 4
> +#  define ATOMIC_HASH(a) (&(__atomic_hash[ (((unsigned long) a)/L1_CACHE_BYTES) & (ATOMIC_HASH_SIZE-1) ]))
> +
> +extern raw_spinlock_t __atomic_hash[ATOMIC_HASH_SIZE] __lock_aligned;
> +
> +/* Can't use raw_spin_lock_irq because of #include problems, so
> + * this is the substitute */
> +#define _atomic_spin_lock_irqsave(l,f) do {	\
> +	raw_spinlock_t *s = ATOMIC_HASH(l);	\
> +	local_irq_save(f);			\
> +	__raw_spin_lock(s);			\
> +} while(0)
> +
> +#define _atomic_spin_unlock_irqrestore(l,f) do {	\
> +	raw_spinlock_t *s = ATOMIC_HASH(l);		\
> +	__raw_spin_unlock(s);				\
> +	local_irq_restore(f);				\
> +} while(0)
> +
> +
> +#else
> +#  define _atomic_spin_lock_irqsave(l,f) do { local_irq_save(f); } while (0)
> +#  define _atomic_spin_unlock_irqrestore(l,f) do { local_irq_restore(f); } while (0)
> +#endif
> +
> +/*
> + * NMI events can occur at any time, including when interrupts have been
> + * disabled by *_irqsave().  So you can get NMI events occurring while a
> + * *_bit function is holding a spin lock.  If the NMI handler also wants
> + * to do bit manipulation (and they do) then you can get a deadlock
> + * between the original caller of *_bit() and the NMI handler.
> + *
> + * by Keith Owens
> + */
> +
> +/**
> + * set_bit - Atomically set a bit in memory
> + * @nr: the bit to set
> + * @addr: the address to start counting from
> + *
> + * This function is atomic and may not be reordered.  See __set_bit()
> + * if you do not require the atomic guarantees.
> + *
> + * Note: there are no guarantees that this function will not be reordered
> + * on non x86 architectures, so if you are writing portable code,
> + * make sure not to rely on its reordering guarantees.
> + *
> + * Note that @nr may be almost arbitrarily large; this function is not
> + * restricted to acting on a single-word quantity.
> + */
> +static inline void set_bit(int nr, volatile unsigned long *addr)
> +{
> +	unsigned long mask = BIT_MASK(nr);
> +	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
> +	unsigned long flags;
> +
> +	_atomic_spin_lock_irqsave(p, flags);
> +	*p  |= mask;
> +	_atomic_spin_unlock_irqrestore(p, flags);
> +}
> +
> +/**
> + * clear_bit - Clears a bit in memory
> + * @nr: Bit to clear
> + * @addr: Address to start counting from
> + *
> + * clear_bit() is atomic and may not be reordered.  However, it does
> + * not contain a memory barrier, so if it is used for locking purposes,
> + * you should call smp_mb__before_clear_bit() and/or smp_mb__after_clear_bit()
> + * in order to ensure changes are visible on other processors.
> + */
> +static inline void clear_bit(int nr, volatile unsigned long *addr)
> +{
> +	unsigned long mask = BIT_MASK(nr);
> +	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
> +	unsigned long flags;
> +
> +	_atomic_spin_lock_irqsave(p, flags);
> +	*p &= ~mask;
> +	_atomic_spin_unlock_irqrestore(p, flags);
> +}
> +
> +/**
> + * change_bit - Toggle a bit in memory
> + * @nr: Bit to change
> + * @addr: Address to start counting from
> + *
> + * change_bit() is atomic and may not be reordered. It may be
> + * reordered on other architectures than x86.
> + * Note that @nr may be almost arbitrarily large; this function is not
> + * restricted to acting on a single-word quantity.
> + */
> +static inline void change_bit(int nr, volatile unsigned long *addr)
> +{
> +	unsigned long mask = BIT_MASK(nr);
> +	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
> +	unsigned long flags;
> +
> +	_atomic_spin_lock_irqsave(p, flags);
> +	*p ^= mask;
> +	_atomic_spin_unlock_irqrestore(p, flags);
> +}
> +
> +/**
> + * test_and_set_bit - Set a bit and return its old value
> + * @nr: Bit to set
> + * @addr: Address to count from
> + *
> + * This operation is atomic and cannot be reordered.
> + * It may be reordered on other architectures than x86.
> + * It also implies a memory barrier.
> + */
> +static inline int test_and_set_bit(int nr, volatile unsigned long *addr)
> +{
> +	unsigned long mask = BIT_MASK(nr);
> +	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
> +	unsigned long old;
> +	unsigned long flags;
> +
> +	_atomic_spin_lock_irqsave(p, flags);
> +	old = *p;
> +	*p = old | mask;
> +	_atomic_spin_unlock_irqrestore(p, flags);
> +
> +	return (old & mask) != 0;
> +}
> +
> +/**
> + * test_and_clear_bit - Clear a bit and return its old value
> + * @nr: Bit to clear
> + * @addr: Address to count from
> + *
> + * This operation is atomic and cannot be reordered.
> + * It can be reorderdered on other architectures other than x86.
> + * It also implies a memory barrier.
> + */
> +static inline int test_and_clear_bit(int nr, volatile unsigned long *addr)
> +{
> +	unsigned long mask = BIT_MASK(nr);
> +	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
> +	unsigned long old;
> +	unsigned long flags;
> +
> +	_atomic_spin_lock_irqsave(p, flags);
> +	old = *p;
> +	*p = old & ~mask;
> +	_atomic_spin_unlock_irqrestore(p, flags);
> +
> +	return (old & mask) != 0;
> +}
> +
> +/**
> + * test_and_change_bit - Change a bit and return its old value
> + * @nr: Bit to change
> + * @addr: Address to count from
> + *
> + * This operation is atomic and cannot be reordered.
> + * It also implies a memory barrier.
> + */
> +static inline int test_and_change_bit(int nr, volatile unsigned long *addr)
> +{
> +	unsigned long mask = BIT_MASK(nr);
> +	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
> +	unsigned long old;
> +	unsigned long flags;
> +
> +	_atomic_spin_lock_irqsave(p, flags);
> +	old = *p;
> +	*p = old ^ mask;
> +	_atomic_spin_unlock_irqrestore(p, flags);
> +
> +	return (old & mask) != 0;
> +}
> +
> +#endif /* _ASM_GENERIC_BITOPS_ATOMIC_H */
> diff --git a/include/asm-nios2/bitops/ffs.h b/include/asm-nios2/bitops/ffs.h
> new file mode 100644
> index 0000000..fbbb43a
> --- /dev/null
> +++ b/include/asm-nios2/bitops/ffs.h
> @@ -0,0 +1,41 @@
> +#ifndef _ASM_GENERIC_BITOPS_FFS_H_
> +#define _ASM_GENERIC_BITOPS_FFS_H_
> +
> +/**
> + * ffs - find first bit set
> + * @x: the word to search
> + *
> + * 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)
> +{
> +	int r = 1;
> +
> +	if (!x)
> +		return 0;
> +	if (!(x & 0xffff)) {
> +		x >>= 16;
> +		r += 16;
> +	}
> +	if (!(x & 0xff)) {
> +		x >>= 8;
> +		r += 8;
> +	}
> +	if (!(x & 0xf)) {
> +		x >>= 4;
> +		r += 4;
> +	}
> +	if (!(x & 3)) {
> +		x >>= 2;
> +		r += 2;
> +	}
> +	if (!(x & 1)) {
> +		x >>= 1;
> +		r += 1;
> +	}
> +	return r;
> +}
> +
> +#endif /* _ASM_GENERIC_BITOPS_FFS_H_ */
> diff --git a/include/asm-nios2/bitops/non-atomic.h b/include/asm-nios2/bitops/non-atomic.h
> new file mode 100644
> index 0000000..697cc2b
> --- /dev/null
> +++ b/include/asm-nios2/bitops/non-atomic.h
> @@ -0,0 +1,108 @@
> +#ifndef _ASM_GENERIC_BITOPS_NON_ATOMIC_H_
> +#define _ASM_GENERIC_BITOPS_NON_ATOMIC_H_
> +
> +#include <asm/types.h>
> +
> +/**
> + * __set_bit - Set a bit in memory
> + * @nr: the bit to set
> + * @addr: the address to start counting from
> + *
> + * Unlike set_bit(), this function is non-atomic and may be reordered.
> + * If it's called on the same region of memory simultaneously, the effect
> + * may be that only one operation succeeds.
> + */
> +static inline void __set_bit(int nr, volatile unsigned long *addr)
> +{
> +	unsigned long mask = BIT_MASK(nr);
> +	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
> +
> +	*p  |= mask;
> +}
> +
> +static inline void __clear_bit(int nr, volatile unsigned long *addr)
> +{
> +	unsigned long mask = BIT_MASK(nr);
> +	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
> +
> +	*p &= ~mask;
> +}
> +
> +/**
> + * __change_bit - Toggle a bit in memory
> + * @nr: the bit to change
> + * @addr: the address to start counting from
> + *
> + * Unlike change_bit(), this function is non-atomic and may be reordered.
> + * If it's called on the same region of memory simultaneously, the effect
> + * may be that only one operation succeeds.
> + */
> +static inline void __change_bit(int nr, volatile unsigned long *addr)
> +{
> +	unsigned long mask = BIT_MASK(nr);
> +	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
> +
> +	*p ^= mask;
> +}
> +
> +/**
> + * __test_and_set_bit - Set a bit and return its old value
> + * @nr: Bit to set
> + * @addr: Address to count from
> + *
> + * This operation is non-atomic and can be reordered.
> + * If two examples of this operation race, one can appear to succeed
> + * but actually fail.  You must protect multiple accesses with a lock.
> + */
> +static inline int __test_and_set_bit(int nr, volatile unsigned long *addr)
> +{
> +	unsigned long mask = BIT_MASK(nr);
> +	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
> +	unsigned long old = *p;
> +
> +	*p = old | mask;
> +	return (old & mask) != 0;
> +}
> +
> +/**
> + * __test_and_clear_bit - Clear a bit and return its old value
> + * @nr: Bit to clear
> + * @addr: Address to count from
> + *
> + * This operation is non-atomic and can be reordered.
> + * If two examples of this operation race, one can appear to succeed
> + * but actually fail.  You must protect multiple accesses with a lock.
> + */
> +static inline int __test_and_clear_bit(int nr, volatile unsigned long *addr)
> +{
> +	unsigned long mask = BIT_MASK(nr);
> +	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
> +	unsigned long old = *p;
> +
> +	*p = old & ~mask;
> +	return (old & mask) != 0;
> +}
> +
> +/* WARNING: non atomic and it can be reordered! */
> +static inline int __test_and_change_bit(int nr,
> +					    volatile unsigned long *addr)
> +{
> +	unsigned long mask = BIT_MASK(nr);
> +	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
> +	unsigned long old = *p;
> +
> +	*p = old ^ mask;
> +	return (old & mask) != 0;
> +}
> +
> +/**
> + * test_bit - Determine whether a bit is set
> + * @nr: bit number to test
> + * @addr: Address to start counting from
> + */
> +static inline int test_bit(int nr, const volatile unsigned long *addr)
> +{
> +	return 1UL & (addr[BIT_WORD(nr)] >> (nr & (BITS_PER_LONG-1)));
> +}
> +
> +#endif /* _ASM_GENERIC_BITOPS_NON_ATOMIC_H_ */