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

From: Sandeep Maheswaram
Date: Tue Mar 30 2021 - 04:43:22 EST



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