Re: prueth: IEP driver doesn't probe anymore

[Romain Naour <romain.naour@smile.fr>]

Hi All,

Le 16/09/2022 à 10:55, Romain Naour a écrit :
> Hi All,
> 
> I'm able to use the prueth driver on a AM5749 cpu using the TI vendor branch
> (ti-linux-5.10.y). But I need a more recent kernel to support other device on my
> custom board. So I had to rebase all the TI work related to the out of tree
> prueth driver on a the latest kernel.
> 
> I hope this driver will be merged in the kernel soon but the series [1] doesn't
> include the prueth driver for AM57xx cpus (only the icssg_prueth for AM65xx is
> included).
> 
> For some reason the IEP driver [2] [3] doesn't probe anymore. Is a side effect
> of recent ti-sysc or legacy platform data work ? I'm using a 5.19.8 stable kernel.
> 
> The prueth_probe() error out with "unable to get IEP" log message.
> 
> Do you have any clue?

I tested several kernel releases between the 5.10 and 5.19 and It turn out that
the issue appear in the 5.13.y kernel.

After a long and time consuming git bisect, the first bad commit is:

Merge tag 'arm-soc-5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=01d7136894410a71932096e0fb9f1d301b6ccf07

Yes this is a merge commit from Linus.

I tested the kernel from each commit parent and the prueth sill works.

So I rebased the branch arm-soc-5.13 merged by Linus to have a fast-forward
history. The second git bisect return this commit as first bad commit:

ARM: dts: Move dra7 l3 noc to a separate node:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=7f2659ce657e87cb7f47e6b15099608eaa1349ac

The switch to ti-sysc seems to have some side effect on some driver like pci-dra7xx:

"After updating pci-dra7xx driver to probe with ti-sysc and genpd, I
noticed that dra7xx_pcie_probe() would not run if a power-domains property
was configured for the interconnect target module."

https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e259c2926c016dd815e5547412356d378fc1f589

This is my current understanding of the issue... but I don't understand the side
effect of the move of the dra7 l3 noc node. Also, there is something merged
before the 'arm-soc-5.13' branch that is a second cause of the issue.

Best regards,
Romain

> 
> Danish, if you can provide a new version of the "PRUSS Remoteproc, Platform
> APIS, and Ethernet Driver" series including the prueth and iep driver for
> AM57xx, I will be able to test it [4].
> 
> Thanks!
> 
> [1] https://lore.kernel.org/netdev/20220406094358.7895-1-p-mohan@ti.com/
> [2]
> https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/commit/?h=ti-linux-5.10.y&id=d3bf5a58c356a90fe14d34f213d6195b9a946dc5
> [3]
> https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/commit/?h=ti-linux-5.10.y&id=7cb095866c8b436176dd783878a9e9c3c0bada0b
> [4]
> https://lore.kernel.org/linux-remoteproc/992019ad-5c58-d420-8a18-a82228f8e086@smile.fr/
> 
> Best regards,
> Romain