Re: [linux-sunxi] [PATCH 2/4] drivers: soc: sunxi: fix error processing on base address when claiming

[Icenowy Zheng]

ä 2017å8æ18æ GMT+08:00 äå2:21:07, Chen-Yu Tsai <wens@xxxxxxxx> åå:
>Hi,
>
>On Wed, Aug 9, 2017 at 4:56 PM, Icenowy Zheng <icenowy@xxxxxxx> wrote:
>> When claiming SRAM, if the base is set to an error, it means that the
>> SRAM controller has been probed, but failed to remap the controller
>> memory zone. If the base is zero, thus the SRAM controller should be
>not
>> probed at all, and it should return -EPROBE_DEFER. However, currently
>we
>> returned -EPROBE_DEFER in the former situation, and ignored the
>latter
>> situation (which will lead to the kernel to panic).
>>
>> Fix the behavior on abnormal base address processing when claiming.
>
>Could you describe how you actually ran into this? The failure seems
>unlikely for a properly written device tree.

In fact it's possible, as the probe defering used to be broken.

On the A64 situation, the SRAM is referenced by the DE2 CCU driver, which will be probed very early -- before SRAM is probed, and the problem happens.

>
>Thanks
>ChenYu