[U-Boot] [U-Boot, 07/18] rockchip: timer: implement timer_get_boot_us

[Philipp Tomsich]

> To make the Rockchip DM timer driver useful for the timing of
> bootstages, we need a few enhancements:
>  - This implements timer_get_boot_us.
>  - This avoids reinitialising the timer, if it has already been
>    set up (e.g. by our TPL and SPL stages). Now, we have a single
>    timebase ticking from TPL through the full U-Boot.
>  - This adds support for reading the timer even before the
>    device-model is ready: we find the timer via /chosen/tick-timer,
>    then read its address and clock-frequency, and finally read the
>    timeval directly).
> 
> Signed-off-by: Philipp Tomsich <philipp.tomsich at theobroma-systems.com>
> ---
> 
>  drivers/timer/rockchip_timer.c | 72 +++++++++++++++++++++++++++++++++++++++---
>  1 file changed, 67 insertions(+), 5 deletions(-)
> 

Acked-by: Philipp Tomsich <philipp.tomsich at theobroma-systems.com>