Re: [PATCH v10 06/10] drm/i915/nvm: add nvm device for discrete graphics

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

On Thu, May 15, 2025 at 04:33:41PM +0300, Alexander Usyskin wrote:
> Enable access to internal non-volatile memory on
> DGFX devices via a child device.
> The nvm child device is exposed via auxiliary bus.

...

> +void intel_nvm_init(struct drm_i915_private *i915)
> +{

Lucas recently revamped xe driver to address this, so let's not hide bugs
and return an error where possible.

> +	struct pci_dev *pdev = to_pci_dev(i915->drm.dev);
> +	struct intel_dg_nvm_dev *nvm;
> +	struct auxiliary_device *aux_dev;
> +	int ret;
> +
> +	/* Only the DGFX devices have internal NVM */
> +	if (!IS_DGFX(i915))
> +		return;
> +
> +	/* Nvm pointer should be NULL here */
> +	if (WARN_ON(i915->nvm))
> +		return;
> +
> +	i915->nvm = kzalloc(sizeof(*nvm), GFP_KERNEL);
> +	if (!i915->nvm)
> +		return;
> +
> +	nvm = i915->nvm;
> +
> +	nvm->writeable_override = true;
> +	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;
> +	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);

Why not just pci_dev_id()?

> +	aux_dev->dev.parent = &pdev->dev;
> +	aux_dev->dev.release = i915_nvm_release_dev;
> +
> +	ret = auxiliary_device_init(aux_dev);
> +	if (ret) {
> +		drm_err(&i915->drm, "i915-nvm aux init failed %d\n", ret);
> +		return;
> +	}
> +
> +	ret = auxiliary_device_add(aux_dev);
> +	if (ret) {
> +		drm_err(&i915->drm, "i915-nvm aux add failed %d\n", ret);
> +		auxiliary_device_uninit(aux_dev);
> +		return;
> +	}
> +}

Raag

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