Re: [U-Boot] [PATCH v2 4/5] time: import time_after, time_before and friends from Linux

On 27 December 2016 at 08:36, Masahiro Yamada yamada.masahiro@socionext.com wrote:

It is not safe to compare timer values directly.

On 32-bit systems, for example, timer_get_us() wraps around every 72 min. (2 ^ 32 / 1000000 =~ 4295 sec =~ 72 min). Depending on the get_ticks() implementation, it may wrap more frequently. The 72 min might be possible on the use of U-Boot.

Let's borrow time_after, time_before, and friends to solve the wrap-around problem.

These macros were copied from include/linux/jiffies.h of Linux 4.9.

Signed-off-by: Masahiro Yamada yamada.masahiro@socionext.com

Changes in v2: None

include/time.h | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+)

Reviewed-by: Simon Glass sjg@chromium.org