[Intel-gfx] [PATCH 1/2] drm/i915/hdcp: Create hdcp_gsc_message in and out

[Kandpal, Suraj]

> On 5/19/2023 2:49 AM, Suraj Kandpal wrote:
> > Add hdcp_gsc_message_in and hdcp_gsc_message_out to help
> > differenctiate the reply given by gsc to avoid any kind of message
> > corruption due message structure reuse.
> > hdcp_gsc_message_out will be filled in upcoming patches
> 
> Generic question on the approach: for both PXP and GSC proxy, we allocate a
> single multi-page object and use the first half for input and the second half
> output. This makes things simpler because we don't need to allocate, map
> and then cleanup 2 separate objects. Any reason not to follow a similar
> approach here?
> 

Tbh I wasn't aware PXP and GSC Proxy were taking this approach maybe I too can modify
the code to use this approach, can you point me towards any reference function which I can have a look at.

Regards,
Suraj Kandpal

> Daniele
> 
> >
> > Cc: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
> > Cc: Alan Previn <alan.previn.teres.alexis at intel.com>
> > Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
> > Signed-off-by: Suraj Kandpal <suraj.kandpal at intel.com>
> > ---
> >   .../gpu/drm/i915/display/intel_display_core.h |  3 +-
> >   drivers/gpu/drm/i915/display/intel_hdcp_gsc.c | 41 +++++++++++++------
> >   2 files changed, 31 insertions(+), 13 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_display_core.h
> > b/drivers/gpu/drm/i915/display/intel_display_core.h
> > index e36f88a39b86..ead16d341f5c 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display_core.h
> > +++ b/drivers/gpu/drm/i915/display/intel_display_core.h
> > @@ -403,7 +403,8 @@ struct intel_display {
> >   		 * reused when sending message to gsc cs.
> >   		 * this is only populated post Meteorlake
> >   		 */
> > -		struct intel_hdcp_gsc_message *hdcp_message;
> > +		struct intel_hdcp_gsc_message *hdcp_message_in;
> > +		struct intel_hdcp_gsc_message *hdcp_message_out;
> >   		/* Mutex to protect the above hdcp component related
> values. */
> >   		struct mutex comp_mutex;
> >   	} hdcp;
> > diff --git a/drivers/gpu/drm/i915/display/intel_hdcp_gsc.c
> > b/drivers/gpu/drm/i915/display/intel_hdcp_gsc.c
> > index 7e52aea6aa17..be505b2d679e 100644
> > --- a/drivers/gpu/drm/i915/display/intel_hdcp_gsc.c
> > +++ b/drivers/gpu/drm/i915/display/intel_hdcp_gsc.c
> > @@ -665,34 +665,51 @@ static int
> > intel_hdcp_gsc_initialize_message(struct drm_i915_private *i915,
> >
> >   static int intel_hdcp_gsc_hdcp2_init(struct drm_i915_private *i915)
> >   {
> > -	struct intel_hdcp_gsc_message *hdcp_message;
> > +	struct intel_hdcp_gsc_message *hdcp_message_in,
> *hdcp_message_out;
> >   	int ret;
> >
> > -	hdcp_message = kzalloc(sizeof(*hdcp_message), GFP_KERNEL);
> > +	hdcp_message_in = kzalloc(sizeof(*hdcp_message_in), GFP_KERNEL);
> >
> > -	if (!hdcp_message)
> > +	if (!hdcp_message_in)
> >   		return -ENOMEM;
> >
> > +	hdcp_message_out = kzalloc(sizeof(*hdcp_message_out),
> GFP_KERNEL);
> > +
> > +	if (!hdcp_message_out)
> > +		return -ENOMEM;
> >   	/*
> >   	 * NOTE: No need to lock the comp mutex here as it is already
> >   	 * going to be taken before this function called
> >   	 */
> > -	i915->display.hdcp.hdcp_message = hdcp_message;
> > -	ret = intel_hdcp_gsc_initialize_message(i915, hdcp_message);
> > +	i915->display.hdcp.hdcp_message_in = hdcp_message_in;
> > +	ret = intel_hdcp_gsc_initialize_message(i915, hdcp_message_in);
> > +
> > +	if (ret) {
> > +		drm_err(&i915->drm, "Could not initialize
> hdcp_message_in\n");
> > +		goto out;
> > +	}
> > +
> > +	i915->display.hdcp.hdcp_message_out = hdcp_message_out;
> > +	ret = intel_hdcp_gsc_initialize_message(i915, hdcp_message_out);
> >
> >   	if (ret)
> > -		drm_err(&i915->drm, "Could not initialize
> hdcp_message\n");
> > +		drm_err(&i915->drm, "Could not initialize
> hdcp_message_out\n");
> >
> > +out:
> >   	return ret;
> >   }
> >
> >   static void intel_hdcp_gsc_free_message(struct drm_i915_private *i915)
> >   {
> > -	struct intel_hdcp_gsc_message *hdcp_message =
> > -					i915->display.hdcp.hdcp_message;
> > -
> > -	i915_vma_unpin_and_release(&hdcp_message->vma,
> I915_VMA_RELEASE_MAP);
> > -	kfree(hdcp_message);
> > +	struct intel_hdcp_gsc_message *hdcp_message_in =
> > +					i915-
> >display.hdcp.hdcp_message_in;
> > +	struct intel_hdcp_gsc_message *hdcp_message_out =
> > +					i915-
> >display.hdcp.hdcp_message_out;
> > +
> > +	i915_vma_unpin_and_release(&hdcp_message_in->vma,
> I915_VMA_RELEASE_MAP);
> > +	i915_vma_unpin_and_release(&hdcp_message_out->vma,
> I915_VMA_RELEASE_MAP);
> > +	kfree(hdcp_message_in);
> > +	kfree(hdcp_message_out);
> >   }
> >
> >   int intel_hdcp_gsc_init(struct drm_i915_private *i915) @@ -782,7
> > +799,7 @@ ssize_t intel_hdcp_gsc_msg_send(struct drm_i915_private
> *i915, u8 *msg_in,
> >   	if (msg_in_len > max_msg_size || msg_out_len > max_msg_size)
> >   		return -ENOSPC;
> >
> > -	hdcp_message = i915->display.hdcp.hdcp_message;
> > +	hdcp_message = i915->display.hdcp.hdcp_message_in;
> >   	header = hdcp_message->hdcp_cmd;
> >   	addr = i915_ggtt_offset(hdcp_message->vma);
> >