Re: [PATCH v8 11/35] drm/i915: Check HDCP 1.4 and 2.2 link on CP_IRQ

[Daniel Vetter <daniel@ffwll.ch>]

On Tue, Nov 27, 2018 at 04:13:09PM +0530, Ramalingam C wrote:
> On DP HDCP1.4 and 2.2, when CP_IRQ is received, start the link
> integrity check for the HDCP version that is enabled.
> 
> v2:
>   Rebased. Function name is changed.
> v3:
>   No Changes.
> v4:
>   No Changes.
> v5:
>   No Changes.
> v6:
>   %s/_in_force/_in_use [Sean Paul]
> v7:
>   Rebased.
> v8:
>   Rebased.
> 
> Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
> cc: Sean Paul <seanpaul@chromium.org>
> Reviewed-by: Sean Paul <seanpaul@chromium.org>
> ---
>  drivers/gpu/drm/i915/intel_dp.c   |  2 +-
>  drivers/gpu/drm/i915/intel_drv.h  |  2 +-
>  drivers/gpu/drm/i915/intel_hdcp.c | 29 +++++++++++++++++++++++++++++
>  3 files changed, 31 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index ac62af073688..ecc4706db7dc 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -4532,7 +4532,7 @@ static void intel_dp_check_service_irq(struct intel_dp *intel_dp)
>  		intel_dp_handle_test_request(intel_dp);
>  
>  	if (val & DP_CP_IRQ)
> -		intel_hdcp_check_link(intel_dp->attached_connector);
> +		intel_hdcp_handle_cp_irq(intel_dp->attached_connector);
>  
>  	if (val & DP_SINK_SPECIFIC_IRQ)
>  		DRM_DEBUG_DRIVER("Sink specific irq unhandled\n");
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index e6e32bf52568..d5ab1ff9cc69 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -2082,11 +2082,11 @@ int intel_hdcp_init(struct intel_connector *connector,
>  		    bool hdcp2_supported);
>  int intel_hdcp_enable(struct intel_connector *connector);
>  int intel_hdcp_disable(struct intel_connector *connector);
> -int intel_hdcp_check_link(struct intel_connector *connector);
>  bool is_hdcp_supported(struct drm_i915_private *dev_priv, enum port port);
>  bool intel_hdcp_capable(struct intel_connector *connector);
>  bool is_hdcp2_supported(struct drm_i915_private *dev_priv);
>  void intel_hdcp_exit(struct drm_i915_private *dev_priv);
> +void intel_hdcp_handle_cp_irq(struct intel_connector *connector);

Renaming doesn't seem to gain us anything, pls drop.

>  
>  /* intel_psr.c */
>  #define CAN_PSR(dev_priv) (HAS_PSR(dev_priv) && dev_priv->psr.sink_support)
> diff --git a/drivers/gpu/drm/i915/intel_hdcp.c b/drivers/gpu/drm/i915/intel_hdcp.c
> index df0fb6d9200b..b9e5f73c640d 100644
> --- a/drivers/gpu/drm/i915/intel_hdcp.c
> +++ b/drivers/gpu/drm/i915/intel_hdcp.c
> @@ -117,6 +117,26 @@ static bool intel_hdcp2_capable(struct intel_connector *connector)
>  	return capable;
>  }
>  
> +static inline bool intel_hdcp_in_use(struct intel_connector *connector)
> +{
> +	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
> +	enum port port = connector->encoder->port;
> +	u32 reg;
> +
> +	reg = I915_READ(PORT_HDCP_STATUS(port));
> +	return reg & (HDCP_STATUS_AUTH | HDCP_STATUS_ENC);
> +}
> +
> +static inline bool intel_hdcp2_in_use(struct intel_connector *connector)
> +{
> +	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
> +	enum port port = connector->encoder->port;
> +	u32 reg;
> +
> +	reg = I915_READ(HDCP2_STATUS_DDI(port));
> +	return reg & (LINK_ENCRYPTION_STATUS | LINK_AUTH_STATUS);
> +}
> +
>  static int intel_hdcp_poll_ksv_fifo(struct intel_digital_port *intel_dig_port,
>  				    const struct intel_hdcp_shim *shim)
>  {
> @@ -2008,3 +2028,12 @@ void intel_hdcp_atomic_check(struct drm_connector *connector,
>  						   new_state->crtc);
>  	crtc_state->mode_changed = true;
>  }
> +
> +/* Handles the CP_IRQ raised from the DP HDCP sink */
> +void intel_hdcp_handle_cp_irq(struct intel_connector *connector)
> +{
> +	if (intel_hdcp_in_use(connector))

Reading registers to figure out what we're doing is bad style. I think
reading register to double-check that our sw-side tracking is correct is
good, so maybe put these checks into hdcp1/2_check_link in a WARN_ON. But
here we should take the hdcp mutex and look at the sw state.

This will naturally fall out of the check_link worker merging in the
earlier patch I think.
-Daniel

> +		intel_hdcp_check_link(connector);
> +	else if (intel_hdcp2_in_use(connector))
> +		intel_hdcp2_check_link(connector);
> +}
> -- 
> 2.7.4
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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