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

[Raag Jadav <raag.jadav@intel.com>]

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.

> +	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?

> +	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.

> +	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