[U-Boot] [PATCH v3] arm: socfpga: fix issue with warm reset when CSEL is 0

[Marek Vasut]

On 02/20/2017 03:35 PM, Dalon Westergreen wrote:
> On Mon, 2017-02-20 at 15:24 +0100, Marek Vasut wrote:
>> On 02/20/2017 03:21 PM, Dalon Westergreen wrote:
>>>
>>> On Mon, 2017-02-20 at 15:14 +0100, Marek Vasut wrote:
>>>>
>>>> On 02/20/2017 03:10 PM, Dalon Westergreen wrote:
>>>>>
>>>>>
>>>>> On Mon, 2017-02-20 at 10:07 +0100, Marek Vasut wrote:
>>>>>>
>>>>>>
>>>>>> On 02/18/2017 02:34 AM, Dalon Westergreen wrote:
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> When CSEL=0x0 the socfpga bootrom does not touch the clock
>>>>>>> configuration for the device.  This can lead to a boot failure
>>>>>>> on warm resets. This patch disables warm resets when CSEL=0.
>>>>>>> This results in the clock and pll configurations being reset
>>>>>>> on any reset issued when CSEL=0.
>>>>>>>
>>>>>>> Signed-off-by: Dalon Westergreen <dwesterg at gmail.com>
>>>>>>
>>>>>> What about my suggestion for V2 about just loading function pointer
>>>>>> into
>>>>>> the reset jump address register ?
>>>>>
>>>>> Frankly, i really dont like relying on the existence of a snippet of
>>>>> code in
>>>>> the
>>>>> onchip ram being untouched to ensure a reboot/reset will occur for this
>>>>> csel=0
>>>>> case.  i am certain this case is rarely used, and confident that it isnt
>>>>> being
>>>>> used while trying to preserve sdram contents.
>>>>
>>>> Well, you already rely on such snippet, it's SPL. If you corrupt SPL and
>>>> do warm reset, your system hangs, I had that multiple times :)
>>>
>>> True.  I would argue to just use cold resets but i think arria 10 has more
>>> use
>>> for the warm reset case.
>>
>> OK
>>
>>>
>>>>
>>>>>
>>>>>
>>>>> the downside is that the scorecard is reset every boot. so the bootrom
>>>>> will
>>>>> retry all the spl images again resulting in possibly longer boot times.
>>>>
>>>> Is that significant ?
>>>
>>> The watchdog timeout is on the order of 1.5 seconds.  That would be for each
>>> failed spl.
>>
>> Hm, OK. But then your system is kinda broken, so you should expect this
>> I guess.
> 
> My thought exactly...  I would like to see if Chin Liang or Dinh have any
> comments?

Agreed, this needs more input

-- 
Best regards,
Marek Vasut