drm/i915/hdcp: HDCP stream encryption support

Both HDCP_{1.x,2.x} requires to select/deselect Multistream HDCP bit
in TRANS_DDI_FUNC_CTL in order to enable/disable stream HDCP
encryption over DP MST Transport Link.

HDCP 1.4 stream encryption requires to validate the stream encryption
status in HDCP_STATUS_{TRANSCODER,PORT} register driving that link
in order to enable/disable the stream encryption.

Both of above requirement are same for all Gen with respect to
B.Spec Documentation.

v2:
- Cosmetic changes function name, error msg print and
  stream typo fixes. [Uma]
v3:
- uniformity for connector detail in DMESG. [Ram]

Cc: Ramalingam C <ramalingam.c@intel.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Reviewed-by: Ramalingam C <ramalingam.c@intel.com>
Tested-by: Karthik B S <karthik.b.s@intel.com>
Signed-off-by: Anshuman Gupta <anshuman.gupta@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210111081120.28417-8-anshuman.gupta@intel.com

drivers/gpu/drm/i915/display/intel_ddi.c

@@ -2099,9 +2099,9 @@ void intel_ddi_disable_transcoder_func(const struct intel_crtc_state *crtc_state
 	}
 }
 
-int intel_ddi_toggle_hdcp_signalling(struct intel_encoder *intel_encoder,
+int intel_ddi_toggle_hdcp_bits(struct intel_encoder *intel_encoder,
 			       enum transcoder cpu_transcoder,
-				     bool enable)
+			       bool enable, u32 hdcp_mask)
 {
 	struct drm_device *dev = intel_encoder->base.dev;
 	struct drm_i915_private *dev_priv = to_i915(dev);
@@ -2116,9 +2116,9 @@ int intel_ddi_toggle_hdcp_signalling(struct intel_encoder *intel_encoder,
 
 	tmp = intel_de_read(dev_priv, TRANS_DDI_FUNC_CTL(cpu_transcoder));
 	if (enable)
-		tmp |= TRANS_DDI_HDCP_SIGNALLING;
+		tmp |= hdcp_mask;
 	else
-		tmp &= ~TRANS_DDI_HDCP_SIGNALLING;
+		tmp &= ~hdcp_mask;
 	intel_de_write(dev_priv, TRANS_DDI_FUNC_CTL(cpu_transcoder), tmp);
 	intel_display_power_put(dev_priv, intel_encoder->power_domain, wakeref);
 	return ret;

drivers/gpu/drm/i915/display/intel_ddi.h

@@ -50,9 +50,9 @@ u32 bxt_signal_levels(struct intel_dp *intel_dp,
 		      const struct intel_crtc_state *crtc_state);
 u32 ddi_signal_levels(struct intel_dp *intel_dp,
 		      const struct intel_crtc_state *crtc_state);
-int intel_ddi_toggle_hdcp_signalling(struct intel_encoder *intel_encoder,
+int intel_ddi_toggle_hdcp_bits(struct intel_encoder *intel_encoder,
 			       enum transcoder cpu_transcoder,
-				     bool enable);
+			       bool enable, u32 hdcp_mask);
 void icl_sanitize_encoder_pll_mapping(struct intel_encoder *encoder);
 
 #endif /* __INTEL_DDI_H__ */

drivers/gpu/drm/i915/display/intel_display_types.h

@@ -343,6 +343,10 @@ struct intel_hdcp_shim {
 				 enum transcoder cpu_transcoder,
 				 bool enable);
 
+	/* Enable/Disable stream encryption on DP MST Transport Link */
+	int (*stream_encryption)(struct intel_connector *connector,
+				 bool enable);
+
 	/* Ensures the link is still protected */
 	bool (*check_link)(struct intel_digital_port *dig_port,
 			   struct intel_connector *connector);

drivers/gpu/drm/i915/display/intel_dp_hdcp.c

@@ -16,6 +16,30 @@
 #include "intel_dp.h"
 #include "intel_hdcp.h"
 
+static unsigned int transcoder_to_stream_enc_status(enum transcoder cpu_transcoder)
+{
+	u32 stream_enc_mask;
+
+	switch (cpu_transcoder) {
+	case TRANSCODER_A:
+		stream_enc_mask = HDCP_STATUS_STREAM_A_ENC;
+		break;
+	case TRANSCODER_B:
+		stream_enc_mask = HDCP_STATUS_STREAM_B_ENC;
+		break;
+	case TRANSCODER_C:
+		stream_enc_mask = HDCP_STATUS_STREAM_C_ENC;
+		break;
+	case TRANSCODER_D:
+		stream_enc_mask = HDCP_STATUS_STREAM_D_ENC;
+		break;
+	default:
+		stream_enc_mask = 0;
+	}
+
+	return stream_enc_mask;
+}
+
 static void intel_dp_hdcp_wait_for_cp_irq(struct intel_hdcp *hdcp, int timeout)
 {
 	long ret;
@@ -622,24 +646,57 @@ static const struct intel_hdcp_shim intel_dp_hdcp_shim = {
 };
 
 static int
-intel_dp_mst_hdcp_toggle_signalling(struct intel_digital_port *dig_port,
-				    enum transcoder cpu_transcoder,
+intel_dp_mst_toggle_hdcp_stream_select(struct intel_connector *connector,
 				       bool enable)
 {
-	struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev);
+	struct intel_digital_port *dig_port = intel_attached_dig_port(connector);
+	struct drm_i915_private *i915 = to_i915(connector->base.dev);
+	struct intel_hdcp *hdcp = &connector->hdcp;
 	int ret;
 
-	if (!enable)
-		usleep_range(6, 60); /* Bspec says >= 6us */
-
-	ret = intel_ddi_toggle_hdcp_signalling(&dig_port->base,
-					       cpu_transcoder, enable);
+	ret = intel_ddi_toggle_hdcp_bits(&dig_port->base,
+					 hdcp->stream_transcoder, enable,
+					 TRANS_DDI_HDCP_SELECT);
 	if (ret)
-		drm_dbg_kms(&i915->drm, "%s HDCP signalling failed (%d)\n",
+		drm_err(&i915->drm, "%s HDCP stream select failed (%d)\n",
 			enable ? "Enable" : "Disable", ret);
 	return ret;
 }
 
+static int
+intel_dp_mst_hdcp_stream_encryption(struct intel_connector *connector,
+				    bool enable)
+{
+	struct intel_digital_port *dig_port = intel_attached_dig_port(connector);
+	struct drm_i915_private *i915 = to_i915(connector->base.dev);
+	struct intel_hdcp *hdcp = &connector->hdcp;
+	enum port port = dig_port->base.port;
+	enum transcoder cpu_transcoder = hdcp->stream_transcoder;
+	u32 stream_enc_status;
+	int ret;
+
+	ret = intel_dp_mst_toggle_hdcp_stream_select(connector, enable);
+	if (ret)
+		return ret;
+
+	stream_enc_status =  transcoder_to_stream_enc_status(cpu_transcoder);
+	if (!stream_enc_status)
+		return -EINVAL;
+
+	/* Wait for encryption confirmation */
+	if (intel_de_wait_for_register(i915,
+				       HDCP_STATUS(i915, cpu_transcoder, port),
+				       stream_enc_status,
+				       enable ? stream_enc_status : 0,
+				       HDCP_ENCRYPT_STATUS_CHANGE_TIMEOUT_MS)) {
+		drm_err(&i915->drm, "Timed out waiting for transcoder: %s stream encryption %s\n",
+			transcoder_name(cpu_transcoder), enable ? "enabled" : "disabled");
+		return -ETIMEDOUT;
+	}
+
+	return 0;
+}
+
 static
 bool intel_dp_mst_hdcp_check_link(struct intel_digital_port *dig_port,
 				  struct intel_connector *connector)
@@ -656,11 +713,15 @@ bool intel_dp_mst_hdcp_check_link(struct intel_digital_port *dig_port,
 						  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);
+			    "[%s:%d] failed QSES ret=%d\n",
+			    connector->base.name, connector->base.base.id, ret);
 		return false;
 	}
 
+	drm_dbg_kms(&i915->drm, "[%s:%d] QSES stream auth: %d stream enc: %d\n",
+		    connector->base.name, connector->base.base.id,
+		    reply.auth_completed, reply.encryption_enabled);
+
 	return reply.auth_completed && reply.encryption_enabled;
 }
 
@@ -673,7 +734,8 @@ static const struct intel_hdcp_shim intel_dp_mst_hdcp_shim = {
 	.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,
+	.toggle_signalling = intel_dp_hdcp_toggle_signalling,
+	.stream_encryption = intel_dp_mst_hdcp_stream_encryption,
 	.check_link = intel_dp_mst_hdcp_check_link,
 	.hdcp_capable = intel_dp_hdcp_capable,
 

drivers/gpu/drm/i915/display/intel_hdmi.c

@@ -1494,15 +1494,16 @@ static int kbl_repositioning_enc_en_signal(struct intel_connector *connector,
 		usleep_range(25, 50);
 	}
 
-	ret = intel_ddi_toggle_hdcp_signalling(&dig_port->base, cpu_transcoder,
-					       false);
+	ret = intel_ddi_toggle_hdcp_bits(&dig_port->base, cpu_transcoder,
+					 false, TRANS_DDI_HDCP_SIGNALLING);
 	if (ret) {
 		drm_err(&dev_priv->drm,
 			"Disable HDCP signalling failed (%d)\n", ret);
 		return ret;
 	}
-	ret = intel_ddi_toggle_hdcp_signalling(&dig_port->base, cpu_transcoder,
-					       true);
+
+	ret = intel_ddi_toggle_hdcp_bits(&dig_port->base, cpu_transcoder,
+					 true, TRANS_DDI_HDCP_SIGNALLING);
 	if (ret) {
 		drm_err(&dev_priv->drm,
 			"Enable HDCP signalling failed (%d)\n", ret);
@@ -1525,8 +1526,9 @@ int intel_hdmi_hdcp_toggle_signalling(struct intel_digital_port *dig_port,
 	if (!enable)
 		usleep_range(6, 60); /* Bspec says >= 6us */
 
-	ret = intel_ddi_toggle_hdcp_signalling(&dig_port->base, cpu_transcoder,
-					       enable);
+	ret = intel_ddi_toggle_hdcp_bits(&dig_port->base,
+					 cpu_transcoder, enable,
+					 TRANS_DDI_HDCP_SIGNALLING);
 	if (ret) {
 		drm_err(&dev_priv->drm, "%s HDCP signalling failed (%d)\n",
 			enable ? "Enable" : "Disable", ret);

drivers/gpu/drm/i915/i915_reg.h

@@ -9960,6 +9960,7 @@ enum skl_power_gate {
 #define  TRANS_DDI_DP_VC_PAYLOAD_ALLOC	(1 << 8)
 #define  TRANS_DDI_HDMI_SCRAMBLER_CTS_ENABLE (1 << 7)
 #define  TRANS_DDI_HDMI_SCRAMBLER_RESET_FREQ (1 << 6)
+#define  TRANS_DDI_HDCP_SELECT		REG_BIT(5)
 #define  TRANS_DDI_BFI_ENABLE		(1 << 4)
 #define  TRANS_DDI_HIGH_TMDS_CHAR_RATE	(1 << 4)
 #define  TRANS_DDI_HDMI_SCRAMBLING	(1 << 0)