drm/i915: Add HDCP framework + base implementation

This patch adds the framework required to add HDCP support to intel
connectors. It implements Aksv loading from fuse, and parts 1/2/3
of the HDCP authentication scheme.

Note that without shim implementations, this does not actually implement
HDCP. That will come in subsequent patches.

Changes in v2:
- Don't open code wait_fors (Chris)
- drm_hdcp.c under MIT license (Daniel)
- Move intel_hdcp_disable() call above ddi_disable (Ram)
- Fix // comments (I wore a cone of shame for 12 hours to atone) (Daniel)
- Justify intel_hdcp_shim with comments (Daniel)
- Fixed async locking issues by adding hdcp_mutex (Daniel)
- Don't alter connector_state in enable/disable (Daniel)
Changes in v3:
- Added hdcp_mutex/hdcp_value to make async reasonable
- Added hdcp_prop_work to separate link checking & property setting
- Added new helper for atomic_check state tracking (Daniel)
- Moved enable/disable into atomic_commit with matching helpers
- Moved intel_hdcp_check_link out of all locks when called from dp
- Bumped up ksv_fifo timeout (noticed failure on one of my dongles)
Changes in v4:
- Remove SKL_ prefix from most register names (Daniel)
- Move enable/disable back to modeset path (Daniel)
- s/get_random_long/get_random_u32/ (Daniel)
- Remove mode_config.mutex lock in prop_work (Daniel)
- Add intel_hdcp_init to handle init of conn components (Daniel)
- Actually check return value of attach_property
- Check Bksv is valid before trying to authenticate (Ram)
Changes in v5:
- checkpatch whitespace changes
- s/DRM_MODE_CONTENT_PROTECTION_OFF/DRM_MODE_CONTENT_PROTECTION_UNDESIRED/
- Fix ksv list wait timeout (actually wait 5s)
- Increase the R0 timeout to 300ms (Ram)
Changes in v6:
- SPDX license

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Ramalingam C <ramalingm.c@intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20180108195545.218615-6-seanpaul@chromium.org

drivers/gpu/drm/i915/intel_ddi.c

@@ -2423,6 +2423,11 @@ static void intel_enable_ddi(struct intel_encoder *encoder,
 		intel_enable_ddi_hdmi(encoder, crtc_state, conn_state);
 	else
 		intel_enable_ddi_dp(encoder, crtc_state, 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));
 }
 
 static void intel_disable_ddi_dp(struct intel_encoder *encoder,
@@ -2457,6 +2462,8 @@ static void intel_disable_ddi(struct intel_encoder *encoder,
 			      const struct intel_crtc_state *old_crtc_state,
 			      const struct drm_connector_state *old_conn_state)
 {
+	intel_hdcp_disable(to_intel_connector(old_conn_state->connector));
+
 	if (intel_crtc_has_type(old_crtc_state, INTEL_OUTPUT_HDMI))
 		intel_disable_ddi_hdmi(encoder, old_crtc_state, old_conn_state);
 	else