Re: [PATCH v2 6/9] Revert "iommu/arm-smmu: Make arm-smmu-v3 explicitly non-modular"

Will Deacon
2019-11-08T16:47:37Z

On Fri, Nov 08, 2019 at 04:44:25PM +0000, John Garry wrote:
> On 08/11/2019 16:17, John Garry wrote:
> > On 08/11/2019 15:16, Will Deacon wrote:
> > > +MODULE_DEVICE_TABLE(of, arm_smmu_of_match);
> >
> > Hi Will,
> >
> > >   static struct platform_driver arm_smmu_driver = {
> > >       .driver    = {
> > >           .name        = "arm-smmu-v3",
> > >           .of_match_table    = of_match_ptr(arm_smmu_of_match),
> > > -        .suppress_bind_attrs = true,
> >
> > Does this mean that we can now manually unbind this driver from the SMMU
> > device?
> >
> > Seems dangerous. Here's what happens for me:
> >
> > root@ubuntu:/sys# cd ./bus/platform/drivers/arm-smmu-v3
> > ind @ubuntu:/sys/bus/platform/drivers/arm-smmu-v3# echo
> > arm-smmu-v3.0.auto > unbind
> > [   77.580351] hisi_sas_v2_hw HISI0162:01: CQE_AXI_W_ERR (0x800) found!
> > ho [   78.635473] platform arm-smmu-v3.0.auto: CMD_SYNC timeout at
> > 0x00000146 [hwprod 0x00000146, hwcons 0x00000000]
> >
> > >       },
> > >       .probe    = arm_smmu_device_probe,
> > > +    .remove    = arm_smmu_device_remove,
> > >       .shutdown = arm_smmu_device_shutdown,
> > >   };
> > > -builtin_platform_driver(arm_smmu_driver);
> > > +module_platform_driver(arm_smmu_driver);
> > > +
>
> BTW, it now looks like it was your v1 series I was testing there, on your
> branch iommu/module. It would be helpful to update for ease of testing.

Yes, sorry about that. I'll update it now (although I'm not sure it will
help with this -- I was going to see what happens with other devices such
as the intel-iommu or storage controllers)

Will