[Intel-gfx] [PATCH] drm/i915/huc: Add HuC fw loading support

[Srivatsa, Anusha]

>-----Original Message-----
>From: Chris Wilson [mailto:chris at chris-wilson.co.uk]
>Sent: Wednesday, January 11, 2017 6:24 AM
>To: Wajdeczko, Michal <Michal.Wajdeczko at intel.com>
>Cc: Srivatsa, Anusha <anusha.srivatsa at intel.com>; intel-
>gfx at lists.freedesktop.org; Alex Dai <yu.dai at intel.com>; Peter Antoine
><peter.antoine at intel.com>
>Subject: Re: [Intel-gfx] [PATCH] drm/i915/huc: Add HuC fw loading support
>
>On Wed, Jan 11, 2017 at 03:13:29PM +0100, Michal Wajdeczko wrote:
>> > +	vma = i915_gem_object_ggtt_pin(huc_fw->obj, NULL, 0, 0, 0);
>> > +	if (IS_ERR(vma)) {
>> > +		DRM_DEBUG_DRIVER("pin failed %d\n", (int)PTR_ERR(vma));
>> > +		return PTR_ERR(vma);
>> > +	}
>
>Just asking a stupid question: Does the HuC have the same limitation as the GuC
>on not being able to map certain ranges of the GuC? From the earlier discussion
>on the failures, I got the impression the HuC had the same limitations.

Hi Chris. I confirmed that HuC does have the limitations.
>> > +
>> > +	/* Invalidate GuC TLB to let GuC take the latest updates to GTT. */
>> > +	I915_WRITE(GEN8_GTCR, GEN8_GTCR_INVALIDATE);
>> > +
>> > +	intel_uncore_forcewake_get(dev_priv, FORCEWAKE_ALL);
>> > +
>> > +	/* init WOPCM */
>> > +	I915_WRITE(GUC_WOPCM_SIZE, intel_guc_wopcm_size(dev_priv));
>> > +	I915_WRITE(DMA_GUC_WOPCM_OFFSET,
>GUC_WOPCM_OFFSET_VALUE |
>> > +			HUC_LOADING_AGENT_GUC);
>> > +
>> > +	/* Set the source address for the uCode */
>> > +	offset = i915_ggtt_offset(vma) + huc_fw->header_offset;
>
>If huc does have the same limits as the guc, please use guc_ggtt_offset() for the
>extra verification on the address before use.

Yes. Thanks a lot for bringing this up.
>-Chris
>
>--
>Chris Wilson, Intel Open Source Technology Centre