Re: Grub doesn’t load devicetree

[Tomaž Zaman]

Doesn’t work - at least not correctly:

=> fatload mmc 0:1 $fdt_addr_r /boot/dtb/fsl-ls1046a-rdb-sdk.dtb
31793 bytes read in 4 ms (7.6 MiB/s)
=> fatload mmc 0:1 $kernel_addr_r /EFI/boot/grubaa64.efi
3978688 bytes read in 168 ms (22.6 MiB/s)
=> setenv fman_ucode
=> bootefi $kernel_addr_r $fdt_addr_r
Failed to load EFI variables
WARNING failed to get smmu node: FDT_ERR_NOTFOUND
WARNING failed to get smmu node: FDT_ERR_NOTFOUND
Booting /\EFI\boot\grubaa64.efi
Welcome to GRUB!

Because of those FDT_ERR_NOTFOUND kernel reports a bunch of errors and doesn’t boot with all the hardware support I need it to.

On the other hand, if I run the same kernel/devicetree/initramfs with booti, bypassing the Grub completely, it works fine. The problem is, I need Grub2 for his project.

Tomaž Zaman, CEO
Mono Technologies Inc.
+386 30 651 645

[cid:98510E94234546F0B7D19E62D33FDFCC]

On 29 Aug 2024 at 10:02 +0200, Peter Robinson <pbrobinson at gmail.com>, wrote:
On Thu, 29 Aug 2024 at 05:14, Tomaž Zaman <tomaz at mono.si> wrote:

I’m working on an arm64 board with an NXP LS1046A CPU and I simply cannot get Grub to load a different device tree than the one that’s provided to it by the EFI Stub.

=> fatload mmc 0:1 $kernel_addr_r /EFI/boot/grubaa64.efi
=> fatload mmc 0:1 $fdt_addr_r /boot/dtb/fsl-ls1046a-rdb-sdk.dtb
=> bootefi $kernel_addr_r $fdt_addr_r

At his point, I get a couple of errors like “smmu node not found”.

However, if I, instead of "fsl-ls1046a-rdb-sdk.dtb” use "fsl-ls1046a-rdb.dtb”, then I get to Grub without any errors.

And this is where I encounter the issue. Because I would like to use a different DTB for booting Linux than the one that’s provided by the EFI configuration table, I set

devicetree /boot/dtb/fsl-ls1046a-rdb-sdk.dtb
linux /boot/vmlinuz-6.6.3-arm64
initrd /boot/initrd.img-6.6.3-arm64

In this case, the devicetree instruction gets ignored completely, and before I see kernel loading, the message “Using FDT from the EFI configuration table"

Is there a way for me to override/replace the device tree that u-boot passed to Grub? I tried passing the “dtb=“ parameter to the kernel boot command, but in that case, I get "EFI stub: ERROR: Failed to handle fs_proto” because kernel when booting doesn’t appear to have access to the same filesystem that Grub does.

Why don't you load a new one into memory with u-boot and then grub
will already have the one you want to use and grun doesn't need to do
anything. Something like this on the U-Boot command line would load
the DT and grub and start to boot:

load mmc 0:1 ${kernel_addr_r} EFI/BOOT/BOOTAA64.EFI
load mmc 0:1 ${fdt_addr_r} dtb/${fdtfile}
bootefi ${kernel_addr_r} ${fdt_addr_r}

You'll need to adjust for storage, partitions, file paths etc.

Thank you!


(this is my first time using *any* mailing list, so apologies if this is the wrong address to send this question to)

Tomaž Zaman, CEO
Mono Technologies Inc.
+386 30 651 645

[cid:18EB2FEE485A4DD7A1CE716CE14FCBC7]

-------------- next part --------------
A non-text attachment was scrubbed...
Name: 98510E94234546F0B7D19E62D33FDFCC.png
Type: image/png
Size: 5014 bytes
Desc: 98510E94234546F0B7D19E62D33FDFCC.png
URL: <https://lists.denx.de/pipermail/u-boot/attachments/20240829/89d5fc4d/attachment.png>