[PATCH v10 08/10] drm/xe/nvm: add on-die non-volatile memory device

[Usyskin, Alexander]

> Subject: Re: [PATCH v10 08/10] drm/xe/nvm: add on-die non-volatile
> memory device
> 
> On Thu, May 15, 2025 at 04:33:43PM +0300, Alexander Usyskin wrote:
> > Enable access to internal non-volatile memory on DGFX
> > with GSC/CSC devices via a child device.
> > The nvm child device is exposed via auxiliary bus.
> 
> ...
> 
> > +void xe_nvm_init(struct xe_device *xe)
> > +{
> 
> Same as patch 6, please handle errors.
This device failure is non-fatal for Xe, caller will ignore
the failure anyway.

> 
> > +	struct pci_dev *pdev = to_pci_dev(xe->drm.dev);
> > +	struct intel_dg_nvm_dev *nvm;
> > +	struct auxiliary_device *aux_dev;
> > +	int ret;
> > +
> > +	if (!xe->info.has_gsc_nvm)
> > +		return;
> > +
> > +	/* No access to internal NVM from VFs */
> > +	if (IS_SRIOV_VF(xe))
> > +		return;
> > +
> > +	/* Nvm pointer should be NULL here */
> > +	if (WARN_ON(xe->nvm))
> > +		return;
> > +
> > +	xe->nvm = kzalloc(sizeof(*nvm), GFP_KERNEL);
> > +	if (!xe->nvm)
> > +		return;
> > +
> > +	nvm = xe->nvm;
> > +
> > +	nvm->writeable_override = false;
> > +	nvm->bar.parent = &pdev->resource[0];
> > +	nvm->bar.start = GEN12_GUNIT_NVM_BASE + pdev-
> >resource[0].start;
> > +	nvm->bar.end = nvm->bar.start + GEN12_GUNIT_NVM_SIZE - 1;
> 
> Just out of curiosity, why off by one? Aren't ioremaps all PAGE_SIZEd?

Was here all the time, never questioned this.
> 
> > +	nvm->bar.flags = IORESOURCE_MEM;
> > +	nvm->bar.desc = IORES_DESC_NONE;
> > +	nvm->regions = regions;
> > +
> > +	aux_dev = &nvm->aux_dev;
> > +
> > +	aux_dev->name = "nvm";
> > +	aux_dev->id = (pci_domain_nr(pdev->bus) << 16) |
> > +		       PCI_DEVID(pdev->bus->number, pdev->devfn);
> 
> Ditto as patch 6.
Will do
> 
> > +	aux_dev->dev.parent = &pdev->dev;
> > +	aux_dev->dev.release = xe_nvm_release_dev;
> > +
> > +	ret = auxiliary_device_init(aux_dev);
> > +	if (ret) {
> > +		drm_err(&xe->drm, "xe-nvm aux init failed %d\n", ret);
> > +		return;
> > +	}
> > +
> > +	ret = auxiliary_device_add(aux_dev);
> > +	if (ret) {
> > +		drm_err(&xe->drm, "xe-nvm aux add failed %d\n", ret);
> > +		auxiliary_device_uninit(aux_dev);
> > +		return;
> > +	}
> > +}
> 
> Raag