GPTIMER1 u-boot

Radu Donos

Hello!

I work with AM335x. I need to work with the system clock (from linux) in u-boot.

I found in dmesg the following:

[ 0.000000] OMAP clockevent source: GPTIMER2 at 24000000 Hz
[ 0.000000] OMAP clocksource: GPTIMER1 at 32768 Hz
...
[ 0.160186] Switching to clocksource gp timer

If I understood correctly the linux system clock is GPTIMER1.

How can I access this timer from u-boot? (I need to calibrate the system clock)

Best regards!

over 11 years ago

0 Biser Gatchev-XID over 11 years ago

TI__Guru**** 393215 points

There is some information on what GPTIMER1 is used for here: http://e2e.ti.com/support/arm/sitara_arm/f/791/p/180128/654090.aspx#654090

0 Radu Donos over 11 years ago in reply to Biser Gatchev-XID

Prodigy 130 points

Thank you for quick response, but unfortunately I did not find there what I needed.

How can I use timers interrupts in u-boot? Maybe someone has already done timers IRQ's in u-boot?

Does anyone have an example how to initialize and work with a timer on 32.768 kHz in u-boot?
Thanks in advance.

0 Steve Kipisz over 11 years ago in reply to Radu Donos

TI__Genius 15510 points

U-Boot does not use interrupts; it works in a polled mode. U-Boot uses TIMER2 in a polled mode to read time. Look at arch/arm/cpu/armv7/omap-common/timer.c.

Steve K.

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GPTIMER1 u-boot