VDSO needs real-time cycle count to ensure the time accuracy.
Unlike others, nds32 architecture does not define clock source,
hence VDSO needs atcpit100 offering real-time cycle count
to derive the correct time.
Signed-off-by: Vincent Chen <vincentc@andestech.com>
Signed-off-by: Rick Chen <rickchen36@gmail.com>
Signed-off-by: Greentime Hu <green.hu@gmail.com>
ATCPIT100 is often used on the Andes architecture,
This timer provide 4 PIT channels. Each PIT channel is a
multi-function timer, can be configured as 32,16,8 bit timers
or PWM as well.
For system timer it will set channel 1 32-bit timer0 as clock
source and count downwards until underflow and restart again.
It also set channel 0 32-bit timer0 as clock event and count
downwards until condition match. It will generate an interrupt
for handling periodically.
Signed-off-by: Rick Chen <rickchen36@gmail.com>
Signed-off-by: Greentime Hu <green.hu@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Add andestech atcpit100 timer
Rick Chen