[PATCH 1/3] ARM: atomic.h: add 64-bit counter support

[Ahmad Fatoum]

On 02.08.21 12:40, Renaud Barbier wrote:
> In preparation for the introduction of the FSL IFC nand driver
> for the layerscape CPU, add 64-bit counter support.
> 
> Remove functions calling undefined functions.
> 
> Signed-off-by: Renaud Barbier <renaud.barbier at abaco.com>
> ---
>  include/asm-generic/atomic-long.h | 63 -------------------------------
>  include/asm-generic/atomic.h      | 49 ++++++++++++++++++++++++
>  2 files changed, 49 insertions(+), 63 deletions(-)
> 
> diff --git a/include/asm-generic/atomic-long.h b/include/asm-generic/atomic-long.h
> index 322d510f38..fd1fdad20f 100644
> --- a/include/asm-generic/atomic-long.h
> +++ b/include/asm-generic/atomic-long.h
> @@ -66,69 +66,6 @@ static inline void atomic_long_sub(long i, atomic_long_t *l)
>  	atomic64_sub(i, v);
>  }
>  
> -static inline int atomic_long_sub_and_test(long i, atomic_long_t *l)
> -{
> -	atomic64_t *v = (atomic64_t *)l;
> -
> -	return atomic64_sub_and_test(i, v);
> -}
> -
> -static inline int atomic_long_dec_and_test(atomic_long_t *l)
> -{
> -	atomic64_t *v = (atomic64_t *)l;
> -
> -	return atomic64_dec_and_test(v);
> -}
> -
> -static inline int atomic_long_inc_and_test(atomic_long_t *l)
> -{
> -	atomic64_t *v = (atomic64_t *)l;
> -
> -	return atomic64_inc_and_test(v);
> -}
> -
> -static inline int atomic_long_add_negative(long i, atomic_long_t *l)
> -{
> -	atomic64_t *v = (atomic64_t *)l;
> -
> -	return atomic64_add_negative(i, v);
> -}
> -
> -static inline long atomic_long_add_return(long i, atomic_long_t *l)
> -{
> -	atomic64_t *v = (atomic64_t *)l;
> -
> -	return (long)atomic64_add_return(i, v);
> -}
> -
> -static inline long atomic_long_sub_return(long i, atomic_long_t *l)
> -{
> -	atomic64_t *v = (atomic64_t *)l;
> -
> -	return (long)atomic64_sub_return(i, v);
> -}
> -
> -static inline long atomic_long_inc_return(atomic_long_t *l)
> -{
> -	atomic64_t *v = (atomic64_t *)l;
> -
> -	return (long)atomic64_inc_return(v);
> -}
> -
> -static inline long atomic_long_dec_return(atomic_long_t *l)
> -{
> -	atomic64_t *v = (atomic64_t *)l;
> -
> -	return (long)atomic64_dec_return(v);
> -}
> -
> -static inline long atomic_long_add_unless(atomic_long_t *l, long a, long u)
> -{
> -	atomic64_t *v = (atomic64_t *)l;
> -
> -	return (long)atomic64_add_unless(v, a, u);
> -}
> -

No one is using the deleted atomic_long_ functions. So that's ok.

>  #define atomic_long_inc_not_zero(l) atomic64_inc_not_zero((atomic64_t *)(l))
>  
>  #define atomic_long_cmpxchg(l, old, new) \
> diff --git a/include/asm-generic/atomic.h b/include/asm-generic/atomic.h
> index 449cecaabc..6e63b8e8e7 100644
> --- a/include/asm-generic/atomic.h
> +++ b/include/asm-generic/atomic.h
> @@ -11,7 +11,55 @@
>  #ifdef CONFIG_SMP
>  #error SMP not supported
>  #endif
> +#define ATOMIC_INIT(i)	{ (i) }
> +
> +#ifdef CONFIG_64BIT
> +typedef struct { s64 counter; } atomic64_t;
> +
> +#define atomic64_read(v)	((v)->counter)
> +#define atomic64_set(v, i)	(((v)->counter) = (i))
> +
> +static inline void atomic64_add(s64 i, volatile atomic64_t *v)
> +{
> +	v->counter += i;
> +}
> +
> +static inline void atomic64_sub(s64 i, volatile atomic64_t *v)
> +{
> +	v->counter -= i;
> +}
> +
> +static inline void atomic64_inc(volatile atomic64_t *v)
> +{
> +	v->counter += 1;
> +}
> +
> +static inline void atomic64_dec(volatile atomic64_t *v)
> +{
> +	v->counter -= 1;
> +}
> +
> +static inline int atomic64_dec_and_test(volatile atomic64_t *v)
> +{
> +	s64 val;
> +
> +	val = v->counter;
> +	v->counter = val -= 1;
> +
> +	return val == 0;

That's a very awkward way to write

return --v->counter == 0;

But I see you just copied the 32 bit variants, so:

Reviewed-by: Ahmad Fatoum <a.fatoum at pengutronix.de>

> +}
>  
> +static inline int atomic64_add_negative(s64 i, volatile atomic64_t *v)
> +{
> +	s64 val;
> +
> +	val = v->counter;
> +	v->counter = val += i;
> +
> +	return val < 0;
> +}
> +
> +#else
>  typedef struct { volatile int counter; } atomic_t;
>  
>  #define ATOMIC_INIT(i)	{ (i) }
> @@ -63,6 +111,7 @@ static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr)
>  {
>  	*addr &= ~mask;
>  }
> +#endif
>  
>  /* Atomic operations are already serializing on ARM */
>  #define smp_mb__before_atomic_dec()	barrier()
> 


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