Re: [PATCH v1] usb: dwc3: core: Add shutdown callback for dwc3

Sandeep Maheswaram
2021-03-30T08:43:23Z

On 3/26/2021 7:07 PM, Greg Kroah-Hartman wrote:
> On Wed, Mar 24, 2021 at 12:57:32AM +0530, Sandeep Maheswaram wrote:
>> This patch adds a shutdown callback to USB DWC core driver to ensure that
>> it is properly shutdown in reboot/shutdown path. This is required
>> where SMMU address translation is enabled like on SC7180
>> SoC and few others. If the hardware is still accessing memory after
>> SMMU translation is disabled as part of SMMU shutdown callback in
>> system reboot or shutdown path, then IOVAs(I/O virtual address)
>> which it was using will go on the bus as the physical addresses which
>> might result in unknown crashes (NoC/interconnect errors).
>>
>> Previously this was added in dwc3 qcom glue driver.
>> https://patchwork.kernel.org/project/linux-arm-msm/list/?series=382449
>> But observed kernel panic as glue driver shutdown getting called after
>> iommu shutdown. As we are adding iommu nodes in dwc core node
>> in device tree adding shutdown callback in core driver seems correct.
> So shouldn't you also remove this from the qcom glue driver at the same
> time? Please submit both as a patch series.
>
> thanks,
>
> greg k-h

Hi Greg,

The qcom glue driver patch is not merged yet. I have just mentioned for it for reference.

Regards
Sandeep