[PATCH 1/2] drm/amd: Use portable do_div helper

[Christian König]

Am 19.09.2017 um 22:23 schrieb Felix Kuehling:
> Signed-off-by: Felix Kuehling <Felix.Kuehling at amd.com>

Acked-by: Christian König <christian.koenig at amd.com> for both.

> ---
>   drivers/gpu/drm/amd/lib/chash.c | 30 +++++++++++++++++++++++-------
>   1 file changed, 23 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/lib/chash.c b/drivers/gpu/drm/amd/lib/chash.c
> index 1bc4287..e07e6f3 100644
> --- a/drivers/gpu/drm/amd/lib/chash.c
> +++ b/drivers/gpu/drm/amd/lib/chash.c
> @@ -27,6 +27,7 @@
>   #include <linux/slab.h>
>   #include <linux/module.h>
>   #include <linux/sched/clock.h>
> +#include <asm/div64.h>
>   #include <linux/chash.h>
>   
>   /**
> @@ -70,9 +71,21 @@ EXPORT_SYMBOL(chash_table_free);
>   #ifdef CONFIG_CHASH_STATS
>   
>   #define DIV_FRAC(nom, denom, quot, frac, frac_digits) do {		\
> -		(quot) = (nom) / (denom);				\
> -		(frac) = ((nom) % (denom) * (frac_digits) +		\
> -			  (denom) / 2) / (denom);			\
> +		u64 __nom = (nom);					\
> +		u64 __denom = (denom);					\
> +		u64 __quot, __frac;					\
> +		u32 __rem;						\
> +									\
> +		while (__denom >> 32) {					\
> +			__nom   >>= 1;					\
> +			__denom >>= 1;					\
> +		}							\
> +		__quot = __nom;						\
> +		__rem  = do_div(__quot, __denom);			\
> +		__frac = __rem * (frac_digits) + (__denom >> 1);	\
> +		do_div(__frac, __denom);				\
> +		(quot) = __quot;					\
> +		(frac) = __frac;					\
>   	} while (0)
>   
>   void __chash_table_dump_stats(struct __chash_table *table)
> @@ -562,7 +575,7 @@ module_param_named(test_iters, chash_test_iters, ulong, 0444);
>   static int __init chash_init(void)
>   {
>   	int ret;
> -	u64 ts1_ns, ts_delta_us;
> +	u64 ts1_ns;
>   
>   	/* Skip self test on user errors */
>   	if (chash_test_bits < 4 || chash_test_bits > 20) {
> @@ -603,10 +616,13 @@ static int __init chash_init(void)
>   			      chash_test_minfill, chash_test_maxfill,
>   			      chash_test_iters);
>   	if (!ret) {
> -		ts_delta_us = (local_clock() - ts1_ns) / 1000;
> +		u64 ts_delta_us = local_clock() - ts1_ns;
> +		u64 iters_per_second = (u64)chash_test_iters * 1000000;
> +
> +		do_div(ts_delta_us, 1000);
> +		do_div(iters_per_second, ts_delta_us);
>   		pr_info("chash: self test took %llu us, %llu iterations/s\n",
> -			ts_delta_us,
> -			(u64)chash_test_iters * 1000000 / ts_delta_us);
> +			ts_delta_us, iters_per_second);
>   	} else {
>   		pr_err("chash: self test failed: %d\n", ret);
>   	}