Revert "ARM: socfpga: Remove socfpga_sdram_apply_static_cfg()

[Marek Vasut]

On 8/7/20 12:58 PM, Wolfgang Grandegger wrote:
> Am 06.08.20 um 14:50 schrieb Marek Vasut:
>> On 8/6/20 2:36 PM, Wolfgang Grandegger wrote:
>>> Am 06.08.20 um 13:04 schrieb Marek Vasut:
>>>> On 8/6/20 12:53 PM, Wolfgang Grandegger wrote:
>>>>> This reverts commit c5f4b805755912a3d2fe20f014b6b6ab0473bd73.
>>>>>
>>>>> Conflicts:
>>>>> 	arch/arm/mach-socfpga/misc_gen5.c
>>>>>
>>>>> Without socfpga_sdram_apply_static_cfg(), the system hangs when Linux
>>>>> calls altvipfb2_start_hw() of the Intel Video and Image Processing(VIP)
>>>>> Frame Buffer II driver (drivers/video/fbdev/altvipfb2.c)
>>>>
>>>> There is no such driver in mainline U-Boot or Linux.
>>>
>>> It's a simple frame buffer driver from linux-socfpga for the IP core
>>> Intel Video and Image Processing(VIP) Frame Buffer II. It actually
>>> hangs here when the streaming starts:
>>>
>>> https://github.com/altera-opensource/linux-socfpga/blob/socfpga-5.4.44-lts/drivers/video/fbdev/altvipfb2.c#L69
>>>
>>> I can also hang the system if I setup and start the FB with just a
>>> few U-Boot commands. I think the system hangs when the IP core starts
>>> reading the FB data from the system memory.
>>
>> I am CCing Dinh , I recall there was some discussion about hangs on
>> CycloneV and it was fixed recently.
>>
>>>>> , but only
>>>>> after a power cycle (cold boot). The issue does not show up after a
>>>>> soft reset (warm boot) and with v2018.11.
>>>>
>>>> See the commit message of the patch this is reverting, I believe there
>>>> is a deeper issue with the static config register. Can you investigate?
>>>
>>> I read the commit message, but well, I can't follow all the details :(.
>>> On the other hand, it seems also not clear why the fix was added. Any
>>> idea what to investigate.
>>
>> The system was repeatedly rebooted in a loop, the FPGA was loaded before
>> Linux booted. After hundreds of reboots, the system got stuck on setting
>> up the static cfg register. I think there was even another email
> 
> I rebooted Linux on my MCVEVP more than 100 times with and without
> loading the FPGA in U-Boot. The system never hang!

It could very well be bitstream related, wait for Simon to chime in.
Do you load the bitstream in U-Boot or in Linux ?

>> exchange where the suggestion was to make this apply_static_cfg optional
>> and only use it when the DRAM port is enabled in the quartus design.
>> Maybe that is the way out of this ?
> 
> Yep.

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