a) Changing the operating behaviour of A5 core =>
We are running linux on Cosmic Phytec VF6XX board, in order to reduce the power consumed by the board, we require A5 core to switch to ultra-low power mode when it is idle. Can you specify how to achieve this in linux ?
Note: We have identified power modes for Vybrid. Please find attached power-mode.png
b) Implementing CPU to CPU interrupt in mcc =>
We have identified existence of cpu to cpu interrrupts in mcc but how to trigger interrupt from a mqx program and handle those interrupts in linux. Do you have some documentation regarding that on the same board ? Please find attached cpu-cpu-interrupt.png
As noted in the same thread we have in the Timesys Support queue, util-linux provides similar functionality to that which you see in Ubuntu.
Following up from the thread you have in our Support queue:
A. Standard Linux Power Management, as detailed in the Documentation shipped with the kernel source applies:
Vybrid linux-3.13 supports LP-RUN and STOP modes, whereas linux-3.0 only supports LP-RUN.
B. The MQX demos for Vybrid can serve as examples of MQX generating interrupts, which are then serviced by Linux
For the example of MQX generating an interrupt that Linux services, MCC in MQX will generate interrupts at the end of the mcc_send() and mcc_recv() functions in mcc_api.c (these functions call mcc_generate_cpu_to_cpu_interrupt() to generate the interrupt).
In Linux, the interrupt is serviced by MCC in mcc-kmod/mcc_linux.c, in the cpu_to_cpu_irq_handler() function.
Thank you for the reply. From the link - linux-3.13/Documentation/power , we have identified various power modes that vybrid supports i.e S1,S3 and S4. But how to switch to these power modes in timesys Linux ?
As in Ubuntu, we can achieve same by using command rtcwake. Is there any equivalent to this command on Cosmic Phytec board ? It has Timesys Linux 3.0