ast2500 reboot got stuck in timeriomem_rng_probe()

[Tao Ren]

> Can you show us your devicetree patch? The only things I can think of are
> if you didn't specify the 'quality' attribute (if you don't the quality defaults
> to 0, which marks the device as disabled in the hwrng device list), or if
 > you set a really long period (but I assume you could have sorted that out
 > yourself :)).

Thank you Andrew for the response. I'm using the default settings in aspeed-g5.dtsi:
    - period = <1>;
    - quality = <100>;

After some investigation, I highly suspect it's because some part(s) of the chip are not reset properly, because:
   1) the problem only happens during warn reboot: cold boot works fine.
   2) bootup hangs at a different place if I disable HW_RANDOM_TIMERIOMEM.
   3) the issue is gone if I update aspeed watchdog reset type to system (aspeed,reset-type = "system") in dts file.

Attached the device tree for your reference, and I will refine the file and send out review soon.


Thanks,

Tao

On 8/1/18, 6:41 PM, "Andrew Jeffery" <andrew at aj.id.au> wrote:

    Hi Tao,
    
    On Thu, 2 Aug 2018, at 02:38, Tao Ren wrote:
    > Hi,
    > 
    > I’m upgrading facebook cmm-bmc (ast2500) from 4.1 to openbmc linux 
    > 4.17.2, and when I tried to reboot linux 4.17, system got stuck in  
    > timeriomem_rng_probe() function during boot up. Did anyone hit the 
    > similar issue before? What would be the recommended solution?
    > 
    
    Can you show us your devicetree patch? The only things I can think of are
    if you didn't specify the 'quality' attribute (if you don't the quality defaults
    to 0, which marks the device as disabled in the hwrng device list), or if
    you set a really long period (but I assume you could have sorted that out
    yourself :)).
    
    Cheers,
    
    Andrew
    

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