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Cortex-A9 Cause for wake up from low power mode ( WFI )

Note: This was originally posted on 26th July 2011 at http://forums.arm.com

Hi
I am using cortex-A9 powered soc, it has two a9 cores.

when cpu1 is put in low power mode using the wfi, the processor wakes up unintentionally.
From the Cortex-A9 MPCore TRM, the causes for the wake ups are

The transition from the WFI Standby mode to the Run modeis caused by:

"¢ An interrupt, masked or unmasked.

"¢ An asynchronous data abort, regardless of the value ofthe CPSR.A bit. A pending wake-up event prevents the processor from enteringlow power mode.

"¢ A debug request, regardless of whether debug isenabled.

"¢ A cp15 maintenance request from another processor

"¢ A reset.

Since all Irq's are routed to cpu0, irq is not a cause for the spurious wakeup,
The only cause seems to be the "cp15 maintenance request from another processor"

How to check which of the CP15 maintenance request caused the wakup
is it possible to disable the cp15 maintenance requests from other cpu before going to low power mode.

Thanks

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Virupax ss over 12 years ago

Note: This was originally posted on 27th September 2011 at http://forums.arm.com

Thanks for the reply.
In WFI mode , does the CPU need to handle the maintenance requests ? Does the FW bit can be set to 0 in WFI mode ?
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Virupax ss over 12 years ago

Note: This was originally posted on 27th September 2011 at http://forums.arm.com

Thanks for the reply.
In WFI mode , does the CPU need to handle the maintenance requests ? Does the FW bit can be set to 0 in WFI mode ?
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