Re: Xilinx Zynq 7000 Start of CPU1

[Sebastian Huber]

----- Am 18. Sep 2024 um 11:13 schrieb Sebastian Huber 
sebastian.huber@embedded-brains.de:

> Hello,
> 
> I recently added the support for CPU1 to the xilinx-zynq-a9 machine
> (hw/arm/xilinx_zynq.c). However, the reset behaviour doesn't match exactly 
> with
> the hardware. After a system reset (SRST), the CPU1 should execute a wfe
> instruction and then load the start address from 0xfffffff0:
> 
> https://docs.amd.com/r/en-US/ug585-zynq-7000-SoC-TRM/Starting-Code-on-CPU-1
> 
> It would be great if someone has a hint for me how I can add this startup code
> for CPU1 at address region 0xFFFFFE00 to 0xFFFFFFF0.

I got it working with some hacks in arm_load_kernel() and do_cpu_reset(). In 
arm_load_kernel() had to remove the:

        /*
         * No secondary boot stub; don't use the reset hook that would
         * have set the CPU up to call it
         */
        info->write_secondary_boot = NULL;
        info->secondary_cpu_reset_hook = NULL;

This change probably breaks a lot of things. I am not sure how to address this 
issue.

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0001-hw-arm-xilinx_zynq-Add-CPU1-reset.patch
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