drm/i915: enable dp mst audio

This patch adds support for DP MST audio in i915.

Enable audio codec when DP MST is enabled if has_audio flag is set.
Disable audio codec when DP MST is disabled if has_audio flag is set.

Another separated patches to support DP MST audio will be implemented
in audio driver.

This patch is ported from
commit 3708d5e0 ("drm/i915: start adding dp mst audio")

And because commit 3708d5e0 ("drm/i915: start adding dp mst audio")
breaks MST multi-monitor setups on some platforms, the orignal patch is
reverted by
commit be754b10 ("Revert "drm/i915: start adding dp mst audio"")

As the multi-monitor setups issue is fixed, let's port the patch and
enable the dp mst audio.
Signed-off-by: Libin Yang <libin.yang@intel.com>
Cc: Lyude <cpaul@redhat.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1480334827-112273-3-git-send-email-libin.yang@intel.com

drivers/gpu/drm/i915/intel_dp_mst.c

@@ -37,6 +37,8 @@ static bool intel_dp_mst_compute_config(struct intel_encoder *encoder,
 	struct intel_dp_mst_encoder *intel_mst = enc_to_mst(&encoder->base);
 	struct intel_digital_port *intel_dig_port = intel_mst->primary;
 	struct intel_dp *intel_dp = &intel_dig_port->dp;
+	struct intel_connector *connector =
+		to_intel_connector(conn_state->connector);
 	struct drm_atomic_state *state;
 	int bpp;
 	int lane_count, slots;
@@ -58,6 +60,8 @@ static bool intel_dp_mst_compute_config(struct intel_encoder *encoder,
 
 	state = pipe_config->base.state;
 
+	if (drm_dp_mst_port_has_audio(&intel_dp->mst_mgr, connector->port))
+		pipe_config->has_audio = true;
 	mst_pbn = drm_dp_calc_pbn_mode(adjusted_mode->crtc_clock, bpp);
 
 	pipe_config->pbn = mst_pbn;
@@ -83,6 +87,7 @@ static void intel_mst_disable_dp(struct intel_encoder *encoder,
 	struct intel_dp *intel_dp = &intel_dig_port->dp;
 	struct intel_connector *connector =
 		to_intel_connector(old_conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
 	int ret;
 
 	DRM_DEBUG_KMS("%d\n", intel_dp->active_mst_links);
@@ -93,6 +98,10 @@ static void intel_mst_disable_dp(struct intel_encoder *encoder,
 	if (ret) {
 		DRM_ERROR("failed to update payload %d\n", ret);
 	}
+	if (old_crtc_state->has_audio) {
+		intel_audio_codec_disable(encoder);
+		intel_display_power_put(dev_priv, POWER_DOMAIN_AUDIO);
+	}
 }
 
 static void intel_mst_post_disable_dp(struct intel_encoder *encoder,
@@ -205,6 +214,10 @@ static void intel_mst_enable_dp(struct intel_encoder *encoder,
 	ret = drm_dp_check_act_status(&intel_dp->mst_mgr);
 
 	ret = drm_dp_update_payload_part2(&intel_dp->mst_mgr);
+	if (pipe_config->has_audio) {
+		intel_display_power_get(dev_priv, POWER_DOMAIN_AUDIO);
+		intel_audio_codec_enable(encoder, pipe_config, conn_state);
+	}
 }
 
 static bool intel_dp_mst_enc_get_hw_state(struct intel_encoder *encoder,
@@ -227,6 +240,9 @@ static void intel_dp_mst_enc_get_config(struct intel_encoder *encoder,
 	enum transcoder cpu_transcoder = pipe_config->cpu_transcoder;
 	u32 temp, flags = 0;
 
+	pipe_config->has_audio =
+		intel_ddi_is_audio_enabled(dev_priv, crtc);
+
 	temp = I915_READ(TRANS_DDI_FUNC_CTL(cpu_transcoder));
 	if (temp & TRANS_DDI_PHSYNC)
 		flags |= DRM_MODE_FLAG_PHSYNC;