Re: [PATCH 2/9] ARC: timer: rtc: implement read loop in "C" vs. inline asm

Daniel Lezcano
2016-11-03T17:03:07Z

On Mon, Oct 31, 2016 at 03:48:09PM -0700, Vineet Gupta wrote:
> To allow for easy movement into drivers/clocksource
>
> Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
> ---
> arch/arc/kernel/time.c | 13 +++++--------
> 1 file changed, 5 insertions(+), 8 deletions(-)
>
> diff --git a/arch/arc/kernel/time.c b/arch/arc/kernel/time.c
> index a2db010cde18..2c51e3cafad0 100644
> --- a/arch/arc/kernel/time.c
> +++ b/arch/arc/kernel/time.c
> @@ -153,14 +153,11 @@ static cycle_t arc_read_rtc(struct clocksource *cs)
> cycle_t full;
> } stamp;
>
> -
> - __asm__ __volatile(
> - "1: \n"
> - " lr %0, [AUX_RTC_LOW] \n"
> - " lr %1, [AUX_RTC_HIGH] \n"
> - " lr %2, [AUX_RTC_CTRL] \n"
> - " bbit0.nt %2, 31, 1b \n"
> - : "=r" (stamp.low), "=r" (stamp.high), "=r" (status));
> + do {
> + stamp.low = read_aux_reg(AUX_RTC_LOW);
> + stamp.high = read_aux_reg(AUX_RTC_HIGH);
> + status = read_aux_reg(AUX_RTC_CTRL);
> + } while (!(status & 0x80000000UL));

Replace the literal 0x80000000UL by a macro.

What is the 'status' for ?

> return stamp.full;
> }
> --
> 2.7.4
>