linux-kernel - RE: [PATCH v10 06/10] drm/i915/nvm: add nvm device for discrete graphics

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Message-ID: <CY5PR11MB6366E83555BDF8B89C9DD6D9ED64A@CY5PR11MB6366.namprd11.prod.outlook.com>
Date: Tue, 27 May 2025 06:00:20 +0000
From: "Usyskin, Alexander" <alexander.usyskin@...el.com>
To: "Jadav, Raag" <raag.jadav@...el.com>
CC: Miquel Raynal <miquel.raynal@...tlin.com>, Richard Weinberger
	<richard@....at>, Vignesh Raghavendra <vigneshr@...com>, "De Marchi, Lucas"
	<lucas.demarchi@...el.com>, Thomas Hellström
	<thomas.hellstrom@...ux.intel.com>, "Vivi, Rodrigo" <rodrigo.vivi@...el.com>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, Maxime Ripard
	<mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>, David Airlie
	<airlied@...il.com>, Simona Vetter <simona@...ll.ch>, Jani Nikula
	<jani.nikula@...ux.intel.com>, Joonas Lahtinen
	<joonas.lahtinen@...ux.intel.com>, Tvrtko Ursulin <tursulin@...ulin.net>,
	"Poosa, Karthik" <karthik.poosa@...el.com>, "Abliyev, Reuven"
	<reuven.abliyev@...el.com>, "Weil, Oren jer" <oren.jer.weil@...el.com>,
	"linux-mtd@...ts.infradead.org" <linux-mtd@...ts.infradead.org>,
	"intel-xe@...ts.freedesktop.org" <intel-xe@...ts.freedesktop.org>,
	"dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
	"intel-gfx@...ts.freedesktop.org" <intel-gfx@...ts.freedesktop.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, Tomas Winkler
	<tomasw@...il.com>
Subject: RE: [PATCH v10 06/10] drm/i915/nvm: add nvm device for discrete
 graphics

> Subject: Re: [PATCH v10 06/10] drm/i915/nvm: add nvm device for discrete
> graphics
> 
> 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.
> 
I can return error from this call, but the SPI failure is non-fatal for Xe.
Caller should ignore error from this init.

> > +	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()?
Will do
> 
> > +	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