Re: [PATCH 05/11] RISC-V: drivers/iommu/riscv: Add sysfs interface

[Conor Dooley]

On Thu, Jul 20, 2023 at 11:37:50PM +0200, Krzysztof Kozlowski wrote:
> On 20/07/2023 20:30, Tomasz Jeznach wrote:

> >>> +#define sysfs_dev_to_iommu(dev) \
> >>> +     container_of(dev_get_drvdata(dev), struct riscv_iommu_device, iommu)
> >>> +
> >>> +static ssize_t address_show(struct device *dev,
> >>> +                         struct device_attribute *attr, char *buf)
> >>
> >>
> >> Where is the sysfs ABI documented?
> >>
> > 
> > Sysfs for now is used only to expose selected IOMMU memory mapped
> > registers, with complete documentation in the RISC-V IOMMU Arch Spec
> > [1], and some comments in iommu-bits.h file.
> > LMK If it would be better to put a dedicated file documenting those
> > with the patch itself.
> 
> I meant, you created new sysfs interface. Maybe I missed something in
> the patchset, but each new sysfs interface required documenting in
> Documentation/ABI/.

| expose selected IOMMU memory mapped registers

| Enable sysfs debug / visibility interface providing restricted
| access to hardware registers.

Documentation requirements of sysfs stuff aside, I'm not sure that we
even want a sysfs interface for this in the first place? Seems like, if
at all, this should be debugfs instead? Seems like the only use case for
it is debugging/development...

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