[PATCH] riscv: dts: spacemit: k3-pico-itx: Fix non-functional ethernet TX timing

[E Shattow]

Hi Andrew,

On 6/10/26 02:05, Andrew Rembrandt wrote:
> On Wed, Jun 10, 2026 at 07:14:56 am Inochi Amaoto wrote:
>> Do not do this, just leave the rx-internal-delay-ps untouched.
> 
> Sounds good, I'll leave v1 as-is. Many thanks for the review.
> 
> Regards,
> 
> Andrew
> 
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I do not notice any difference with or without this property present,
tested Linux -next with U-Boot modification to devicetree:

load usb 0:1 $fdt_addr_r /dtb/spacemit/k3-pico-itx.dtb
fdt addr $fdt_addr_r
fdt resize
fdt header get filesize totalsize
fdt set /soc/ethernet at cac80000 tx-internal-delay-ps <400>
load usb 0:1 $kernel_addr_r /EFI/BOOT/BOOTRISCV64.EFI
# throwaway use of ping is workaround for broken vendor U-Boot
ping 127.0.0.1; bootefi $kernel_addr_r $fdt_addr_r

Aside, there is still some problem with the driver which does cause it
to fail. This can be reproduced by unloading the module and then loading
the module; built from -next with 'olddefconfig' of debian Kconfig for
kernel 7.1, no patches.

# modprobe -r dwmac_spacemit
# modprobe dwmac_spacemit
[   61.469745] spacemit-dwmac cac80000.ethernet end0: cannot attach to
PHY (error: -ENODEV)

[   91.544646] spacemit-dwmac cac80000.ethernet end0: cannot attach to
PHY (error: -ENODEV)

If not reloading the module then I don't see any difference, traffic
passes (ping 1.1.1.1) with or without your suggested
tx-internal-delay-ps property. Is there a specific test to run to
observe expected difference?

Thanks,

-E