Access GPIO from remote processor running FreeRTOS in OpenAMP design

Hello,
I've posted this same message to the Xilinx support forum, but thought I'd try here as well.

I have created an AMP configuration using a MicroZed board where the master processor is running PetaLinux and the remote processor is running FreeRTOS. This design is based off the proxy_app example and successfully boots both processors and executes code on both processors that communicate using the mechanisms from the example. In addition, I am able to control custom QSPI blocks instantiated within the PL section of the Zynq from the remote process and receive interrupts for these peripherals in the remote processor.

I need to be able to control several GPIOs from the remote processor and I am unable to do this. I first started with GPIOs that are routed to EMIO, but had no luck. I then went back to attempt to use the LED GPIO (on MIO47) on the MicroZed and that fails as well. If I use the same code in a stand-alone project (non-AMP with FreeRTOS code running on processor 0), I can successfully control all the EMIOs, but porting that code to the AMP design does not allow any GPIO control.

Is there some initialization that must be done to allow access to the PS peripherals such as the GPIO or others to be accessed by the remote processor in this configuration?

All tools and Petalinux are version 2015.4. Thanks in advance for any help anyone can provide.

Regards,
Ron

0 Former Member over 5 years ago

Hello Ron,

There are a couple of posts on the Xilinx Community Forums that might address your issue:

https://forums.xilinx.com/t5/OpenAMP/I-O-resource-on-cpu1/td-p/669122

https://forums.xilinx.com/t5/Zynq-All-Programmable-SoC/AMP-spi-drivers-not-working-on-cpu1/td-p/642930

Let us know if this resolves the issue.

-Gary
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0 Former Member over 5 years ago

Thanks Gary. The problem was that these GPIOs needed to have entries in the device tree. I added one for the LED on MIO47 as follows:

gpio-leds {
tcompatible = "gpio-leds";
tled-user47 {
ttlabel = "led-user47";
ttgpios = <&gpio0 47 0>;
t};
};

And my custom GPIOs on EMIO:
gpio {
tadc-gpio0 {
ttlabel = "adc-gpio0";
ttgpios = <&gpio0 54 0>;
t};
tadc-gpio1 {
ttlabel = "adc-gpio1";
ttgpios = <&gpio0 55 0>;
t};
};

Evidently these are needed on the PetaLinux side to enable them for the remote processor. I'm guessing this enables clocks to the devices.

-Ron
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0 byc013 1 month ago in reply to Former Member

Hello Gary,

I'm running an AMP system on Zynq7000 with two cortex A9 cores.
Linux Os on core0 and standalone on core1.

In my case I use remoteproc drivers to load the standalone ELF from Linux user-space based on the rpmsg-proxy-app sample application.

I am trying to access gpios MIOs and EMIOs from my standalone application with no luck so far. I have tried many things.
I also need to access SPI0 from the standalone app with no luck as well.

I was trying to follow the 2 links you've provided here above but they seem to be broken.

Could you please assist me with this IOMEM issue?

Thanks!
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