[meta-xilinx] SPL->ATF->Linux

[Stefano Stabellini]

Hi Peter,

I chatted with Michal about FIT images when he was here a month or two
ago -- it should work for Xen but I haven't had a chance to try it out
yet. I am working on a set of scripts to make it easier to boot Xen,
especially in a dom0less scenario where there are many binaries to be
loaded from u-boot, including the kernels of all VMs, and this could "fit"
very nicely :-)

For Xen and Linux alone, there is probably no need for trampoline code.

Cheers,

Stefano


On Fri, 14 Jun 2019, Peter Ryzer wrote:
>
> I have been following along with interest, do you know if this would work if we wanted to load Xen i.e. to boot a Xen Dom0?
> 
> Best Regards
> 
> Peter
> 
>  
> 
>  
> 
> On Fri, 14 Jun 2019 at 08:36, Michal Simek <michal.simek at xilinx.com> wrote:
> 
>       On 13. 06. 19 17:22, Jean-Francois Dagenais wrote:
>       > Thanks Michal!
>       >
>       > This is awesome. I can certainly use this. Please review my assumptions below...
>       >
>       >> On Jun 12, 2019, at 07:39, Michal Simek <michal.simek at xilinx.com> wrote:
>       >>
>       >> Create bif like this.
>       >> Image - one partition load addr 0x80000 as data
>       >> dtb - one partition load addr 0x100000000 as data
>       >>
>       >> ATF - one partition (as today) EL3
>       >> Trampoline code below() EL2-ns with filled kernel start to 0x80000 and
>       >> dtb at 0x100000000
>       >>
>       >> fsbl starts ATF and it will pass handoff structure and primary program
>       >> will be trampoline executed in EL2 which will just pass proper arguments
>       >> to kernel.
>       >
>       >
>       > So in essence, the program below becomes a standalone binary file which
>       > essentially replaces "u-boot.bin" correct? Let's call it linux-boot.bin
>       > (inspired by comment in code below).
>       >
>       > This would mean that boot.bin file must contain linux-boot.bin so FSBL loads it
>       > to RAM prior to passing execution to ATF. If correct, linux-boot.bin must be
>       > loaded at 0xfffc8000 (if following the example below), correct?
>       >
>       > If I understand all this correctly, I could either use FSBL with a boot.bin
>       > containing basically everything needed to boot up to the kernel, including
>       > linux-boot.bin. Or I could use SPL inside an u-boot's mkimage made boot.bin
>       > configured to load a FIT image containing atf, linux-boot.bin,kernelImage,dtb ?
>       >
>       > If I understand FIT correctly, it is basically a "better", more straight forward
>       > way to load multiples binaries into RAM rather than messing with
>       > CONFIG_SPL_FS_LOAD_ARGS_NAME, CONFIG_SYS_SPL_ARGS_ADDR,
>       > CONFIG_SPL_FS_LOAD_KERNEL_NAME and CONFIG_SPL_FS_LOAD_PAYLOAD_NAME... correct?
> 
>       If you want to boot just linux without u-boot you can simply run
>       FSBL->ATF->linux-boot.bin->Linux. That's what I have described in
>       previous email. And I would put linux-boot.bin to RAM out of Linux image.
> 
>       And sure you can use SPL instead of FSBL which likely don't need to use
>       any trampoline code (linux-boot.bin). If this is packed in FIT I also
>       think that you don't need to use any trampoline for booting. But I
>       didn't test it to be 100% sure.
> 
>       Thanks,
>       Michal
> 
> 
> 
> 
> 
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