Re: [Intel-gfx] [PATCH v7 17/17] drm/i915: Add HDCP 1.4 support for MST connectors

[Anshuman Gupta <anshuman.gupta@intel.com>]

On 2020-08-11 at 13:28:46 -0400, Sean Paul wrote:
> On Thu, Jul 9, 2020 at 8:40 AM Anshuman Gupta <anshuman.gupta@intel.com> wrote:
> >
> 
> \snip
> 
> > > > +static int
> > > > +intel_dp_mst_hdcp_toggle_signalling(struct intel_digital_port *intel_dig_port,
> > > > +                               enum transcoder cpu_transcoder,
> > > > +                               bool enable)
> > > > +{
> > > > +   struct drm_i915_private *i915 = to_i915(intel_dig_port->base.base.dev);
> > > > +   int ret;
> > > > +
> > > > +   if (!enable)
> > > > +           usleep_range(6, 60); /* Bspec says >= 6us */
> > > > +
> > > > +   ret = intel_ddi_toggle_hdcp_signalling(&intel_dig_port->base,
> > > > +                                          cpu_transcoder, enable);
> > > Sean,
> > >
> > > This function toggles the TRANS_DDI_HDCP_SIGNALLING (9th)bit of TRANS_DDI_FUNC_CTL(tran)
> > > But in the hw specification this bit is mentioned to be ignored for non
> > > HDMI/DVI modes of the TRANS DDI.
> > >
> > > Any reason why we need this? Did you try with out this function?
> > >
> 
> Under "Authentication Part 1 for Multi-stream DisplayPort", bspec says:
> 2. Select HDCP for the desired stream using the Pipe DDI Function
> Control register.
This is the 5th bit (Multistream HDCP Select) of Pipe DDI Function Control register i.e
TRANS_DDI_FUNC_CTL register. This bit ensures HDCP encryption to this transcoder stream when used in
multistream DisplayPort mode.
Unfortunately public specs of Gen11 has discrepency and doesn't describe this bit.
https://01.org/sites/default/files/documentation/intel-gfx-prm-osrc-icllp-vol02c-commandreference-registers-part2_0.pdf
Page No.1026 TRANS_DDI_FUNC_CTL
> 
> > > Apart from that Patch looks good to me.
> > IMHO it seems we are still missing to enable the Multistream HDCP Select
> > bit (5) in TRANS_DDI_FUNC_CTL register which is required to enable the
> > stream encryption.
> >
> 
> Could you send me some docs on this? I don't see have info on this bit.
This bit is not described in above mentioned public spec, but neither bit TRANS_DDI_HDCP_SIGNALLING bit (9th)
which used in this patch, what is the source of public B.spec you are following?
Thanks,
Anshuman Gupta.
> 
> Sean
> 
> > Thanks,
> > Anshuman Gupta.
> > >
> > > -Ram
> > >
> > > > +   if (ret)
> > > > +           drm_dbg_kms(&i915->drm, "%s HDCP signalling failed (%d)\n",
> > > > +                         enable ? "Enable" : "Disable", ret);
> > > > +   return ret;
> > > > +}
> > > > +
> > > > +static
> > > > +bool intel_dp_mst_hdcp_check_link(struct intel_digital_port *intel_dig_port,
> > > > +                             struct intel_connector *connector)
> > > > +{
> > > > +   struct drm_i915_private *i915 = to_i915(intel_dig_port->base.base.dev);
> > > > +   struct intel_dp *intel_dp = &intel_dig_port->dp;
> > > > +   struct drm_dp_query_stream_enc_status_ack_reply reply;
> > > > +   int ret;
> > > > +
> > > > +   if (!intel_dp_hdcp_check_link(intel_dig_port, connector))
> > > > +           return false;
> > > > +
> > > > +   ret = drm_dp_send_query_stream_enc_status(&intel_dp->mst_mgr,
> > > > +                                             connector->port, &reply);
> > > > +   if (ret) {
> > > > +           drm_dbg_kms(&i915->drm,
> > > > +                       "[CONNECTOR:%d:%s] failed QSES ret=%d\n",
> > > > +                       connector->base.base.id, connector->base.name, ret);
> > > > +           return false;
> > > > +   }
> > > > +
> > > > +   return reply.auth_completed && reply.encryption_enabled;
> > > > +}
> > > > +
> > > > +static const struct intel_hdcp_shim intel_dp_mst_hdcp_shim = {
> > > > +   .write_an_aksv = intel_dp_hdcp_write_an_aksv,
> > > > +   .read_bksv = intel_dp_hdcp_read_bksv,
> > > > +   .read_bstatus = intel_dp_hdcp_read_bstatus,
> > > > +   .repeater_present = intel_dp_hdcp_repeater_present,
> > > > +   .read_ri_prime = intel_dp_hdcp_read_ri_prime,
> > > > +   .read_ksv_ready = intel_dp_hdcp_read_ksv_ready,
> > > > +   .read_ksv_fifo = intel_dp_hdcp_read_ksv_fifo,
> > > > +   .read_v_prime_part = intel_dp_hdcp_read_v_prime_part,
> > > > +   .toggle_signalling = intel_dp_mst_hdcp_toggle_signalling,
> > > > +   .check_link = intel_dp_mst_hdcp_check_link,
> > > > +   .hdcp_capable = intel_dp_hdcp_capable,
> > > > +
> > > > +   .protocol = HDCP_PROTOCOL_DP,
> > > > +};
> > > > +
> > > >  int intel_dp_init_hdcp(struct intel_digital_port *intel_dig_port,
> > > >                    struct intel_connector *intel_connector)
> > > >  {
> > > > @@ -630,7 +691,10 @@ int intel_dp_init_hdcp(struct intel_digital_port *intel_dig_port,
> > > >     if (!is_hdcp_supported(dev_priv, port))
> > > >             return 0;
> > > >
> > > > -   if (!intel_dp_is_edp(intel_dp))
> > > > +   if (intel_connector->mst_port)
> > > > +           return intel_hdcp_init(intel_connector, port,
> > > > +                                  &intel_dp_mst_hdcp_shim);
> > > > +   else if (!intel_dp_is_edp(intel_dp))
> > > >             return intel_hdcp_init(intel_connector, port,
> > > >                                    &intel_dp_hdcp_shim);
> > > >
> > > > diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> > > > index 0675825dcc20..abaaeeb963d2 100644
> > > > --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> > > > +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> > > > @@ -37,6 +37,7 @@
> > > >  #include "intel_dp.h"
> > > >  #include "intel_dp_mst.h"
> > > >  #include "intel_dpio_phy.h"
> > > > +#include "intel_hdcp.h"
> > > >
> > > >  static int intel_dp_mst_compute_link_config(struct intel_encoder *encoder,
> > > >                                         struct intel_crtc_state *crtc_state,
> > > > @@ -352,6 +353,8 @@ static void intel_mst_disable_dp(struct intel_atomic_state *state,
> > > >     drm_dbg_kms(&i915->drm, "active links %d\n",
> > > >                 intel_dp->active_mst_links);
> > > >
> > > > +   intel_hdcp_disable(intel_mst->connector);
> > > > +
> > > >     drm_dp_mst_reset_vcpi_slots(&intel_dp->mst_mgr, connector->port);
> > > >
> > > >     ret = drm_dp_update_payload_part1(&intel_dp->mst_mgr);
> > > > @@ -548,6 +551,13 @@ static void intel_mst_enable_dp(struct intel_atomic_state *state,
> > > >
> > > >     if (pipe_config->has_audio)
> > > >             intel_audio_codec_enable(encoder, pipe_config, conn_state);
> > > > +
> > > > +   /* Enable hdcp if it's desired */
> > > > +   if (conn_state->content_protection ==
> > > > +       DRM_MODE_CONTENT_PROTECTION_DESIRED)
> > > > +           intel_hdcp_enable(to_intel_connector(conn_state->connector),
> > > > +                             pipe_config->cpu_transcoder,
> > > > +                             (u8)conn_state->hdcp_content_type);
> > > >  }
> > > >
> > > >  static bool intel_dp_mst_enc_get_hw_state(struct intel_encoder *encoder,
> > > > @@ -770,6 +780,14 @@ static struct drm_connector *intel_dp_add_mst_connector(struct drm_dp_mst_topolo
> > > >     intel_attach_force_audio_property(connector);
> > > >     intel_attach_broadcast_rgb_property(connector);
> > > >
> > > > +
> > > > +   /* TODO: Figure out how to make HDCP work on GEN12+ */
> > > > +   if (INTEL_GEN(dev_priv) < 12) {
> > > > +           ret = intel_dp_init_hdcp(intel_dig_port, intel_connector);
> > > > +           if (ret)
> > > > +                   DRM_DEBUG_KMS("HDCP init failed, skipping.\n");
> > > > +   }
> > > > +
> > > >     /*
> > > >      * Reuse the prop from the SST connector because we're
> > > >      * not allowed to create new props after device registration.
> > > > diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c b/drivers/gpu/drm/i915/display/intel_hdcp.c
> > > > index 6bd0e4616ee1..ddc9db8de2bc 100644
> > > > --- a/drivers/gpu/drm/i915/display/intel_hdcp.c
> > > > +++ b/drivers/gpu/drm/i915/display/intel_hdcp.c
> > > > @@ -2060,7 +2060,7 @@ int intel_hdcp_init(struct intel_connector *connector,
> > > >     if (!shim)
> > > >             return -EINVAL;
> > > >
> > > > -   if (is_hdcp2_supported(dev_priv))
> > > > +   if (is_hdcp2_supported(dev_priv) && !connector->mst_port)
> > > >             intel_hdcp2_init(connector, port, shim);
> > > >
> > > >     ret =
> > > > --
> > > > Sean Paul, Software Engineer, Google / Chromium OS
> > > >
> > > _______________________________________________
> > > Intel-gfx mailing list
> > > Intel-gfx@lists.freedesktop.org
> > > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
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