Re: [PATCH 3/4] drm/xe/gsc: add gsc device support

[Daniele Ceraolo Spurio]

On 9/13/2023 5:48 AM, Usyskin, Alexander wrote:
> > > +struct xe_gsc {
> > Please use a different name for this instead of just xe_gsc. In Xe we're
> > likely never going to fully use the GSC via HECI, only the GSCFI/CSC
> > part. In MTL and newer we also have the actual GSC part being split off
> > and placed inside GT (behind the GSCCS), so if we call this just xe_gsc
> > as well it'll be confusing. I suggest calling this something like
> > xe_heci_gsc, xe_heci_interface or something like that. I had actually
> > suggested this for i915 as well
> > (https://patchwork.freedesktop.org/patch/509653/) but Tomas was
> > concerned it might make backporting fixes difficult, so I dropped it;
> > this is not a concern for Xe right now.
> >
> > Note that this means renaming all the exposed functions as well.
> >
> > Daniele
> Sure, will rename it xe_heci_gsc and move to xe_device.
>
> > > diff --git a/drivers/gpu/drm/xe/xe_irq.c b/drivers/gpu/drm/xe/xe_irq.c
> > > index 1dee3e832eb5..1ae4cc9f1522 100644
> > > --- a/drivers/gpu/drm/xe/xe_irq.c
> > > +++ b/drivers/gpu/drm/xe/xe_irq.c
> > > @@ -128,6 +128,7 @@ void xe_irq_enable_hwe(struct xe_gt *gt)
> > >    	struct xe_device *xe = gt_to_xe(gt);
> > >    	u32 ccs_mask, bcs_mask;
> > >    	u32 irqs, dmask, smask;
> > > +	u32 gsc_mask = GSC_IRQ_INTF(1);
> > >
> > >    	if (xe_device_guc_submission_enabled(xe)) {
> > >    		irqs = GT_RENDER_USER_INTERRUPT |
> > > @@ -180,6 +181,9 @@ void xe_irq_enable_hwe(struct xe_gt *gt)
> > >    		if (xe_hw_engine_mask_per_class(gt,
> > XE_ENGINE_CLASS_OTHER)) {
> > >    			xe_mmio_write32(gt, GUNIT_GSC_INTR_ENABLE,
> > irqs);
> > >    			xe_mmio_write32(gt, GUNIT_GSC_INTR_MASK,
> > ~irqs);
> > > +		} else if (HAS_HECI_GSCFI(xe)) {
> > > +			xe_mmio_write32(gt, GUNIT_GSC_INTR_ENABLE,
> > gsc_mask);
> > > +			xe_mmio_write32(gt, GUNIT_GSC_INTR_MASK,
> > ~gsc_mask);
> Danielle, how this enablement should look when gsc_heci is not gt related?
> I'm somewhat confused here.

This one you should be able to leave as-is, and your check in 
HAS_HECI_GSCFI is already at the xe device level and not at the gt 
level. Unfortunately the mmio writes functions only allow a gt parameter 
for now, so we need to stick with that (I believe there is a plan to 
change it at some point).

What will need to change is xe_gsc_irq_handler(), but you can change 
that to take the heci_gsc as a parameter and then do:

    xe_gsc_irq_handler(&gt_to_xe(gt)->heci_gsc, iir);

Daniele

>