[Intel-gfx] [RFC 1/2] drm/i915: Add support for considering HDCP ver requested via debugfs

[Ankit Nautiyal]

For testing and debugging each HDCP version separately, a debugfs
entry for requesting a specific version is required. The vesion
requested via debugfs needs to be stored in hdcp structure. This can
then be considered while enabling HDCP, provided the platform and the
display supports the requested version.

This patch adds the support for storing the version requested as a 32bit
flag. The default value is set to signify that any of the HDCP version
can be used.

If a specific HDCP version is requested through the debugfs, the driver
chooses that version, instead of policy of choosing the highest HDCP
version supported.

Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
---
 drivers/gpu/drm/i915/display/intel_display_types.h | 10 ++++++++++
 drivers/gpu/drm/i915/display/intel_hdcp.c          |  8 ++++++--
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index 9488449e4b94..cfa641c70717 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -408,6 +408,16 @@ struct intel_hdcp {
 	 * Hence caching the transcoder here.
 	 */
 	enum transcoder cpu_transcoder;
+
+	/*
+	 * HDCP version requested from debugfs i915_hdcp_ver_request.
+	 * Kernel will read these bits and entertain the request, as per
+	 * the HDCP capability of the panel and platform.
+	 */
+#define HDCP_VERSION_1_4	0x01
+#define HDCP_VERSION_2_2	0x02
+#define HDCP_VERSION_MASK	0x03
+	u32 debugfs_ver_request;
 };
 
 struct intel_connector {
diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c b/drivers/gpu/drm/i915/display/intel_hdcp.c
index 2cbc4619b4ce..951401046804 100644
--- a/drivers/gpu/drm/i915/display/intel_hdcp.c
+++ b/drivers/gpu/drm/i915/display/intel_hdcp.c
@@ -1977,6 +1977,8 @@ int intel_hdcp_init(struct intel_connector *connector,
 	if (!shim)
 		return -EINVAL;
 
+	hdcp->debugfs_ver_request = HDCP_VERSION_MASK;
+
 	if (is_hdcp2_supported(dev_priv))
 		intel_hdcp2_init(connector, shim);
 
@@ -2023,7 +2025,8 @@ int intel_hdcp_enable(struct intel_connector *connector,
 	 * Considering that HDCP2.2 is more secure than HDCP1.4, If the setup
 	 * is capable of HDCP2.2, it is preferred to use HDCP2.2.
 	 */
-	if (intel_hdcp2_capable(connector)) {
+	if ((hdcp->debugfs_ver_request & HDCP_VERSION_2_2) &&
+	    intel_hdcp2_capable(connector)) {
 		ret = _intel_hdcp2_enable(connector);
 		if (!ret)
 			check_link_interval = DRM_HDCP2_CHECK_PERIOD_MS;
@@ -2033,7 +2036,8 @@ int intel_hdcp_enable(struct intel_connector *connector,
 	 * When HDCP2.2 fails and Content Type is not Type1, HDCP1.4 will
 	 * be attempted.
 	 */
-	if (ret && intel_hdcp_capable(connector) &&
+	if (ret && (hdcp->debugfs_ver_request & HDCP_VERSION_1_4) &&
+	    intel_hdcp_capable(connector) &&
 	    hdcp->content_type != DRM_MODE_HDCP_CONTENT_TYPE1) {
 		ret = _intel_hdcp_enable(connector);
 	}
-- 
2.17.1