[PATCH v5 08/16] drm/i915: Don't fully disable HDCP on a port if multiple pipes are using it

[Sean Paul <sean@poorly.run>]

From: Sean Paul <seanpaul@chromium.org>

This patch is required for HDCP over MST. If a port is being used for
multiple HDCP streams, we don't want to fully disable HDCP on a port if
one of them is disabled. Instead, we just disable the HDCP signalling on
that particular pipe and exit early. The last pipe to disable HDCP will
also bring down HDCP on the port.

In order to achieve this, we need to keep a refcount in intel_digital_port
and protect it using a new hdcp_mutex.

Cc: Ramalingam C <ramalingam.c@intel.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20191203173638.94919-8-sean@poorly.run #v1
Link: https://patchwork.freedesktop.org/patch/msgid/20191212190230.188505-9-sean@poorly.run #v2
Link: https://patchwork.freedesktop.org/patch/msgid/20200117193103.156821-9-sean@poorly.run #v3
Link: https://patchwork.freedesktop.org/patch/msgid/20200218220242.107265-9-sean@poorly.run #v4

Changes in v2:
-Move the toggle_signalling call into _intel_hdcp_disable so it's called from check_work
Changes in v3:
-None
Changes in v4:
-None
Changes in v5:
-Change WARN_ON to drm_WARN_ON
---
 drivers/gpu/drm/i915/display/intel_ddi.c      |  3 ++
 .../drm/i915/display/intel_display_types.h    |  5 ++
 drivers/gpu/drm/i915/display/intel_dp.c       |  2 +
 drivers/gpu/drm/i915/display/intel_hdcp.c     | 53 +++++++++++++++----
 drivers/gpu/drm/i915/display/intel_hdmi.c     |  2 +
 5 files changed, 56 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
index d27f74c8f55d0..48910a2ceaaaa 100644
--- a/drivers/gpu/drm/i915/display/intel_ddi.c
+++ b/drivers/gpu/drm/i915/display/intel_ddi.c
@@ -4452,6 +4452,9 @@ void intel_ddi_init(struct drm_i915_private *dev_priv, enum port port)
 	drm_encoder_init(&dev_priv->drm, &encoder->base, &intel_ddi_funcs,
 			 DRM_MODE_ENCODER_TMDS, "DDI %c", port_name(port));
 
+	mutex_init(&intel_dig_port->hdcp_mutex);
+	intel_dig_port->num_hdcp_streams = 0;
+
 	encoder->hotplug = intel_ddi_hotplug;
 	encoder->compute_output_type = intel_ddi_compute_output_type;
 	encoder->compute_config = intel_ddi_compute_config;
diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index bd577f143469c..04161993e2038 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -1388,6 +1388,11 @@ struct intel_digital_port {
 	enum phy_fia tc_phy_fia;
 	u8 tc_phy_fia_idx;
 
+	/* protects num_hdcp_streams reference count */
+	struct mutex hdcp_mutex;
+	/* the number of pipes using HDCP signalling out of this port */
+	unsigned int num_hdcp_streams;
+
 	void (*write_infoframe)(struct intel_encoder *encoder,
 				const struct intel_crtc_state *crtc_state,
 				unsigned int type,
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index b2e92ecd1e0ff..4a38012a1fb03 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -7800,6 +7800,8 @@ bool intel_dp_init(struct drm_i915_private *dev_priv,
 	intel_encoder = &intel_dig_port->base;
 	encoder = &intel_encoder->base;
 
+	mutex_init(&intel_dig_port->hdcp_mutex);
+
 	if (drm_encoder_init(&dev_priv->drm, &intel_encoder->base,
 			     &intel_dp_enc_funcs, DRM_MODE_ENCODER_TMDS,
 			     "DP %c", port_name(port)))
diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c b/drivers/gpu/drm/i915/display/intel_hdcp.c
index 9523ab6c65e0d..0ee29f88bab2d 100644
--- a/drivers/gpu/drm/i915/display/intel_hdcp.c
+++ b/drivers/gpu/drm/i915/display/intel_hdcp.c
@@ -803,6 +803,19 @@ static int _intel_hdcp_disable(struct intel_connector *connector)
 	drm_dbg_kms(&dev_priv->drm, "[%s:%d] HDCP is being disabled...\n",
 		    connector->base.name, connector->base.base.id);
 
+	/*
+	 * If there are other connectors on this port using HDCP, don't disable
+	 * it. Instead, toggle the HDCP signalling off on that particular
+	 * connector/pipe and exit.
+	 */
+	if (intel_dig_port->num_hdcp_streams > 0) {
+		ret = hdcp->shim->toggle_signalling(intel_dig_port,
+						    cpu_transcoder, false);
+		if (ret)
+			DRM_ERROR("Failed to disable HDCP signalling\n");
+		return ret;
+	}
+
 	hdcp->hdcp_encrypted = false;
 	intel_de_write(dev_priv, HDCP_CONF(dev_priv, cpu_transcoder, port), 0);
 	if (intel_de_wait_for_clear(dev_priv,
@@ -883,6 +896,8 @@ struct intel_connector *intel_hdcp_to_connector(struct intel_hdcp *hdcp)
 static void intel_hdcp_update_value(struct intel_connector *connector,
 				    u64 value, bool update_property)
 {
+	struct drm_device *dev = connector->base.dev;
+	struct intel_digital_port *intel_dig_port = intel_attached_dig_port(connector);
 	struct intel_hdcp *hdcp = &connector->hdcp;
 
 	drm_WARN_ON(connector->base.dev, !mutex_is_locked(&hdcp->mutex));
@@ -890,6 +905,15 @@ static void intel_hdcp_update_value(struct intel_connector *connector,
 	if (hdcp->value == value)
 		return;
 
+	drm_WARN_ON(dev, !mutex_is_locked(&intel_dig_port->hdcp_mutex));
+
+	if (hdcp->value == DRM_MODE_CONTENT_PROTECTION_ENABLED) {
+		if (!drm_WARN_ON(dev, intel_dig_port->num_hdcp_streams == 0))
+			intel_dig_port->num_hdcp_streams--;
+	} else if (value == DRM_MODE_CONTENT_PROTECTION_ENABLED) {
+		intel_dig_port->num_hdcp_streams++;
+	}
+
 	hdcp->value = value;
 	if (update_property) {
 		drm_connector_get(&connector->base);
@@ -908,6 +932,8 @@ static int intel_hdcp_check_link(struct intel_connector *connector)
 	int ret = 0;
 
 	mutex_lock(&hdcp->mutex);
+	mutex_lock(&intel_dig_port->hdcp_mutex);
+
 	cpu_transcoder = hdcp->cpu_transcoder;
 
 	/* Check_link valid only when HDCP1.4 is enabled */
@@ -961,6 +987,7 @@ static int intel_hdcp_check_link(struct intel_connector *connector)
 	}
 
 out:
+	mutex_unlock(&intel_dig_port->hdcp_mutex);
 	mutex_unlock(&hdcp->mutex);
 	return ret;
 }
@@ -2058,6 +2085,7 @@ int intel_hdcp_enable(struct intel_connector *connector,
 		      enum transcoder cpu_transcoder, u8 content_type)
 {
 	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_digital_port *intel_dig_port = intel_attached_dig_port(connector);
 	struct intel_hdcp *hdcp = &connector->hdcp;
 	unsigned long check_link_interval = DRM_HDCP_CHECK_PERIOD_MS;
 	int ret = -EINVAL;
@@ -2066,6 +2094,7 @@ int intel_hdcp_enable(struct intel_connector *connector,
 		return -ENOENT;
 
 	mutex_lock(&hdcp->mutex);
+	mutex_lock(&intel_dig_port->hdcp_mutex);
 	drm_WARN_ON(&dev_priv->drm,
 		    hdcp->value == DRM_MODE_CONTENT_PROTECTION_ENABLED);
 	hdcp->content_type = content_type;
@@ -2100,12 +2129,14 @@ int intel_hdcp_enable(struct intel_connector *connector,
 					true);
 	}
 
+	mutex_unlock(&intel_dig_port->hdcp_mutex);
 	mutex_unlock(&hdcp->mutex);
 	return ret;
 }
 
 int intel_hdcp_disable(struct intel_connector *connector)
 {
+	struct intel_digital_port *intel_dig_port = intel_attached_dig_port(connector);
 	struct intel_hdcp *hdcp = &connector->hdcp;
 	int ret = 0;
 
@@ -2113,17 +2144,21 @@ int intel_hdcp_disable(struct intel_connector *connector)
 		return -ENOENT;
 
 	mutex_lock(&hdcp->mutex);
+	mutex_lock(&intel_dig_port->hdcp_mutex);
 
-	if (hdcp->value != DRM_MODE_CONTENT_PROTECTION_UNDESIRED) {
-		intel_hdcp_update_value(connector,
-					DRM_MODE_CONTENT_PROTECTION_UNDESIRED,
-					false);
-		if (hdcp->hdcp2_encrypted)
-			ret = _intel_hdcp2_disable(connector);
-		else if (hdcp->hdcp_encrypted)
-			ret = _intel_hdcp_disable(connector);
-	}
+	if (hdcp->value == DRM_MODE_CONTENT_PROTECTION_UNDESIRED)
+		goto out;
+
+	intel_hdcp_update_value(connector,
+				DRM_MODE_CONTENT_PROTECTION_UNDESIRED, false);
 
+	if (hdcp->hdcp2_encrypted)
+		ret = _intel_hdcp2_disable(connector);
+	else if (hdcp->hdcp_encrypted)
+		ret = _intel_hdcp_disable(connector);
+
+out:
+	mutex_unlock(&intel_dig_port->hdcp_mutex);
 	mutex_unlock(&hdcp->mutex);
 	cancel_delayed_work_sync(&hdcp->check_work);
 	return ret;
diff --git a/drivers/gpu/drm/i915/display/intel_hdmi.c b/drivers/gpu/drm/i915/display/intel_hdmi.c
index 51db3adb4bf1c..29149b59f9e40 100644
--- a/drivers/gpu/drm/i915/display/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/display/intel_hdmi.c
@@ -3259,6 +3259,8 @@ void intel_hdmi_init(struct drm_i915_private *dev_priv,
 
 	intel_encoder = &intel_dig_port->base;
 
+	mutex_init(&intel_dig_port->hdcp_mutex);
+
 	drm_encoder_init(&dev_priv->drm, &intel_encoder->base,
 			 &intel_hdmi_enc_funcs, DRM_MODE_ENCODER_TMDS,
 			 "HDMI %c", port_name(port));
-- 
Sean Paul, Software Engineer, Google / Chromium OS

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