Revert "ARM: socfpga: Remove socfpga_sdram_apply_static_cfg()

Wolfgang Grandegger wg at
Fri Aug 7 17:49:13 CEST 2020

Am 07.08.20 um 17:05 schrieb Dinh Nguyen:
> CC Hean Loong:
> On 8/6/20 7:36 AM, 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:
>> 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.
> Can you elaborate what you mean here? You are starting the Frame Buffer
> driver with U-Boot?

Yes, the FPGA image provides the Intel Video and Image Processing(VIP)
Frame Buffer II IP core and it is loaded with "> fpga load ..." in
U-Boot before Linux starts. And yes, this IP core does use the DRAM
bridge (F2S).

The systems hangs, if I start the framebuffer in U-Boot or Linux, but
only after a power-cycle. It works fine after a soft-reset.

>>>> , 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.


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