Re: [PATCH v5 5/9] iommu/arm-smmu: Attach to host1x context device bus

[Mikko Perttunen]

On 5/16/22 13:07, Will Deacon wrote:
> On Mon, May 16, 2022 at 11:52:54AM +0300, cyndis@xxxxxxxx wrote:
> > From: Mikko Perttunen <mperttunen@xxxxxxxxxx>
> >
> > Set itself as the IOMMU for the host1x context device bus, containing
> > "dummy" devices used for Host1x context isolation.
> >
> > Signed-off-by: Mikko Perttunen <mperttunen@xxxxxxxxxx>
> > ---
> >   drivers/iommu/arm/arm-smmu/arm-smmu.c | 13 +++++++++++++
> >   1 file changed, 13 insertions(+)
> >
> > diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
> > index 568cce590ccc..9ff54eaecf81 100644
> > --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
> > +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
> > @@ -39,6 +39,7 @@
> >   
> >   #include <linux/amba/bus.h>
> >   #include <linux/fsl/mc.h>
> > +#include <linux/host1x_context_bus.h>
> >   
> >   #include "arm-smmu.h"
> >   
> > @@ -2053,8 +2054,20 @@ static int arm_smmu_bus_init(struct iommu_ops *ops)
> >   			goto err_reset_pci_ops;
> >   	}
> >   #endif
> > +#ifdef CONFIG_TEGRA_HOST1X_CONTEXT_BUS
> > +	if (!iommu_present(&host1x_context_device_bus_type)) {
> > +		err = bus_set_iommu(&host1x_context_device_bus_type, ops);
> > +		if (err)
> > +			goto err_reset_fsl_mc_ops;
> > +	}
> > +#endif
> > +
> >   	return 0;
> >   
> > +err_reset_fsl_mc_ops: __maybe_unused;
> > +#ifdef CONFIG_FSL_MC_BUS
> > +	bus_set_iommu(&fsl_mc_bus_type, NULL);
> > +#endif
>
> bus_set_iommu() is going away:
>
> https://lore.kernel.org/r/cover.1650890638.git.robin.murphy@xxxxxxx
>
> Will

Thanks for the heads-up. Robin had pointed out that this work was 
ongoing but I hadn't seen the patches yet. I'll look into it.

Mikko

> >