Re: Testing the recent RISC-V DT patchsets

[Loys Ollivier]

On Wed 29 May 2019 at 00:50, Atish Patra <atish.patra@xxxxxxx> wrote:

> On 5/28/19 8:36 AM, Karsten Merker wrote:
>> On Tue, May 28, 2019 at 05:10:42PM +0200, Loys Ollivier wrote:
>>> On Tue 28 May 2019 at 01:32, Paul Walmsley <paul.walmsley@xxxxxxxxxx> wrote:
>>>
>>>> An update for those testing RISC-V patches: here's a new branch of
>>>> riscv-pk/bbl that doesn't try to read or modify the DT data at all, which
>>>> should be useful until U-Boot settles down.
>> [...]
>>>> Here is an Linux kernel branch with updated DT data that can be booted
>>>> with the above bootloader:
>>>>
>>>>     https://github.com/sifive/riscv-linux/tree/dev/paulw/dts-v5.2-rc1-experimental
>>>>
>>>> A sample boot log follows, using a 'defconfig' build from that branch.
>>>
>>> Thanks Paul, I can confirm that it works.
>>>
>>> Something is still unclear to myself.
>>> Using FSBL + riscv-pk/bbl the linux kernel + device tree boots.
>>> Neither FSBL nor riscv-pk/bbl are modifying the DT.
>>>
>>> Using FSBL + OpenSBI + U-Boot the same kernel + device tree hangs on
>>> running /init.
>>>
>>> Would you have any pointer on what riscv-pk does that OpenSBI/U-boot doesn't ?
>>> Or maybe it is the other way around - OpenSBI/U-boot does something that
>>> extra that should not happen.
>> 
>> Hello,
>> 
>> I don't know which version of OpenSBI you are using, but there is
>> a problem with the combination of kernel 5.2-rc1 and OpenSBI
>> versions before commit
>> 
>>    https://github.com/riscv/opensbi/commit/4e2cd478208531c47343290f15b577d40c82649c
>> 
>> that can result in a hang on executing init, so in case you
>> should be using an older OpenSBI build that might be the source
>> of the problem that you are experiencing.
>> 
>> Regards,
>> Karsten
>> 
>
> I verified the updated DT with upstream kernel for the boot flow OpenSBI 
> + U-Boot + Linux or OpenSBI + Linux.
>
> OpenSBI should be compiled for sifive platform with following additional 
> argument
>
> FW_PAYLOAD_FDT_PATH=<linux kernel 
> source>/arch/riscv/boot/dts/sifive/hifive-unleashed-a00.dtb
>
> FYI: It will only work when kernel is given a payload to U-Boot/OpenSBI 
> directly.
>

Hum, I am surprised by this statement.
I was able to verify the latest DT patch serie from Paul with:
OpenSBI + U-Boot + Linux & DT.

Following the OpenSBI documentation [0] with U-Boot payload:
FW_PAYLOAD_PATH=<u-boot_build_dir>/u-boot.bin

I get an U-Boot prompt and then I can just load the linux kernel and
device tree from the network.

[0]: https://github.com/riscv/opensbi/blob/master/docs/platform/sifive_fu540.md#building-sifive-fu540-platform

> Network booting is still not working as the clock driver probe doesn't 
> happen because of the updated DT.
>
> -- 
> Regards,
> Atish