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Linux/OMAP4460: NO high resolution timer support for OMAP4 ?

ranchu
Guru 20755 points

Part Number: OMAP4460

Tool/software: Linux

Hello,

I can't find in configuration support for MPU timer, i.e. it's seem that my architecture (omap4) does not support it:

Symbol: OMAP_MPU_TIMER [=n] │
│ Type : boolean │
│ Prompt: Use mpu timer │
│ Defined at arch/arm/plat-omap/Kconfig:189 │
│ Depends on: ARCH_OMAP [=y] && ARCH_OMAP1 [=n] │
│ Location: │
│ -> System Type │
│ -> TI OMAP Common Features │
│ Selected by: ARCH_OMAP730 [=n] && ARCH_OMAP1 [=n] || ARCH_OMAP15XX [= │

Does it mean that I don't have high resolution timer ?

I see that I have 32k timers, but not sure if it is the same as high resolution timers:

ubuntu@ubuntu-laptop:~/malat/src/kernel-ubuntu$ cat .config | grep HZ
# CONFIG_RCU_FAST_NO_HZ is not set
CONFIG_OMAP_32K_TIMER_HZ=128
CONFIG_NO_HZ=y
CONFIG_HZ=128
ubuntu@ubuntu-laptop:~/malat/src/kernel-ubuntu$

Thanks for any feedback,

Ran

  • 0
    TI__Guru**** 161600 points
    Hi Ran,

    There are GP timer & Watchdog dedicated specially to the MPU. However these timers are locked for use access, they cannot be stopped by any hardware means. Their clocks cannot be gated. The GP timer can be accessed only in Secure MPU mode.

    However any additional information about these timers is under NDA and CANNOT be discussed on a public forum.

    Best Regards,
    Yordan
  • 0 in reply to Yordan Kovachev
    Guru 20755 points

    Thank Yordan,

    I'm not sure I understand.

    I worked a lot with GP timer with both omap35xx, davinci (ti81xx), and others.

    Do you mean that the same API for GP timers, is no longer supported with OMAP4 ? 

    )

    Is there any way to use high resolution timers ?

    Can I use HRTIMERS (high resolution timer) in kernel ?

    Thank you,

    Ran