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

Greg Kroah-Hartman
2021-03-26T13:37:39Z

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