Re: [PATCH v5 11/12] drm: Add CP downstream_info property

On Thu, Apr 18, 2019 at 02:28:04PM +0530, Ramalingam C wrote:

This patch adds a optional CP downstream info blob property to the connectors. This enables the Userspace to read the information of HDCP authenticated downstream topology.

Driver will update this blob with all downstream information at the end of the authentication.

In case userspace configures this platform as repeater, then this information is needed for the authentication with upstream HDCP transmitter.

v2: s/cp_downstream/content_protection_downstream [daniel] v3: s/content_protection_downstream/hdcp_topology [daniel] v4: hdcp_topology_info struct is added with explicit padding [Daniel] v5: Rebased.

Signed-off-by: Ramalingam C ramalingam.c@intel.com

drivers/gpu/drm/drm_atomic_uapi.c | 3 ++ drivers/gpu/drm/drm_connector.c | 20 ++++++++++ drivers/gpu/drm/drm_hdcp.c | 65 +++++++++++++++++++++++++++++++ include/drm/drm_connector.h | 6 +++ include/drm/drm_hdcp.h | 6 +++ include/drm/drm_mode_config.h | 6 +++ include/uapi/drm/drm_mode.h | 37 ++++++++++++++++++ 7 files changed, 143 insertions(+)

diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/drm_atomic_uapi.c index 0b0747869963..1c9e1ab0d536 100644 --- a/drivers/gpu/drm/drm_atomic_uapi.c +++ b/drivers/gpu/drm/drm_atomic_uapi.c @@ -813,6 +813,9 @@ drm_atomic_connector_get_property(struct drm_connector *connector, *val = state->content_protection; } else if (property == config->hdcp_content_type_property) { *val = state->hdcp_content_type;

• } else if (property == config->hdcp_topology_property) {

• *val = connector->hdcp_topology_blob_ptr ?
  

• 	connector->hdcp_topology_blob_ptr->base.id : 0;
  

  } else if (property == config->writeback_fb_id_property) { /* Writeback framebuffer is one-shot, write and forget */ *val = 0;

diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c index 436cf8e764cc..033ced774d37 100644 --- a/drivers/gpu/drm/drm_connector.c +++ b/drivers/gpu/drm/drm_connector.c @@ -246,6 +246,7 @@ int drm_connector_init(struct drm_device *dev, mutex_init(&connector->mutex); connector->edid_blob_ptr = NULL; connector->tile_blob_ptr = NULL;

• connector->hdcp_topology_blob_ptr = NULL; connector->status = connector_status_unknown; connector->display_info.panel_orientation = DRM_MODE_PANEL_ORIENTATION_UNKNOWN;

@@ -972,6 +973,25 @@ static const struct drm_prop_enum_list hdmi_colorspaces[] = {

• authentication process. If content type is changed when
• content_protection is not UNDESIRED, then kernel will disable the HDCP
• and re-enable with new type in the same atomic commit

• • HDCP Topology:
• • This blob property is used to pass the HDCP downstream topology details
• • of a HDCP encrypted connector, from kernel to userspace.
• • This provides all required information to userspace, so that userspace
• • can implement the HDCP repeater using the kernel as downstream ports of
• • the repeater. as illustrated below:

• •                      HDCP Repeaters
    

• • +--------------------------------------------------------------+
• • | |
• • | | |
• • | Userspace HDCP Receiver +-----> KMD HDCP transmitters |
• • | (Upstream Port) <------+ (Downstream Ports) |
• • | | |
• • | |
• • +--------------------------------------------------------------+

Hm I think this misrenders, since the table isn't indented or marked as fixed with. Did you check the output of $make htmldocs?

• • Kernel will populate this blob only when the HDCP authentication is
• • successful.
  • max bpc:
  • This range property is used by userspace to limit the bit depth. When

diff --git a/drivers/gpu/drm/drm_hdcp.c b/drivers/gpu/drm/drm_hdcp.c index 5640c4e744fe..c0d3fc93fc50 100644 --- a/drivers/gpu/drm/drm_hdcp.c +++ b/drivers/gpu/drm/drm_hdcp.c @@ -431,3 +431,68 @@ void drm_hdcp_update_content_protection(struct drm_connector *connector, dev->mode_config.content_protection_property); } EXPORT_SYMBOL(drm_hdcp_update_content_protection);

+/**

• • drm_connector_attach_hdcp_topology_property - attach hdcp topology property
• • @connector: connector to attach hdcp topology property with.
• • This is used to add support for hdcp topology support on select connectors.
• • When Intel platform is configured as repeater, this downstream info is used
• • by userspace, to complete the repeater authentication of HDCP specification
• • with upstream HDCP transmitter.
• • The blob_id of the hdcp topology info will be set to
• • &drm_connector_state.hdcp_topology
• • Returns:
• • Zero on success, negative errno on failure.
• */

+int drm_connector_attach_hdcp_topology_property(struct drm_connector *connector) +{

• struct drm_device *dev = connector->dev;
• struct drm_property *prop = dev->mode_config.hdcp_topology_property;
• if (!prop)

• prop = drm_property_create(dev, DRM_MODE_PROP_BLOB |
  

• 			   DRM_MODE_PROP_IMMUTABLE,
  

• 			   "HDCP Topology", 0);
  

• if (!prop)

• return -ENOMEM;
  

• drm_object_attach_property(&connector->base, prop, 0);
• dev->mode_config.hdcp_topology_property = prop;
• return 0;

+} +EXPORT_SYMBOL(drm_connector_attach_hdcp_topology_property);

+/**

• • drm_connector_update_hdcp_topology_property - update the hdcp topology
• • property of a connector
• • @connector: drm connector, the topology is associated to
• • @hdcp_topology_info: new content for the blob of hdcp_topology_property
• • This function creates a new blob modeset object and assigns its id to the
• • connector's hdcp_topology_property.
• • Returns:
• • Zero on success, negative errno on failure.
• */

+int +drm_connector_update_hdcp_topology_property(struct drm_connector *connector,

• 			const struct hdcp_topology_info *info)
  

+{

• struct drm_device *dev = connector->dev;
• int ret;
• if (!info)

• return -EINVAL;
  

• ret = drm_property_replace_global_blob(dev,

• 	&connector->hdcp_topology_blob_ptr,
  

• 	sizeof(struct hdcp_topology_info),
  

• 	info, &connector->base,
  

• 	dev->mode_config.hdcp_topology_property);
  

• return ret;

+}

Hm, I'd put this into the previous function that also sends out the uevent. That way we can guarantee that we update everyting _before_ we send out the uevent to signal to userspace that it should take some action.

+EXPORT_SYMBOL(drm_connector_update_hdcp_topology_property); diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h index 9e2f1a9de2a0..180f8f4d4526 100644 --- a/include/drm/drm_connector.h +++ b/include/drm/drm_connector.h @@ -1050,6 +1050,12 @@ struct drm_connector { /** @properties: property tracking for this connector */ struct drm_object_properties properties;

• /**

• * @hdcp_topology_blob_ptr: DRM BLOB pointer for hdcp downstream
  

• * topology information.
  

• */
  

• struct drm_property_blob *hdcp_topology_blob_ptr;
• /**
  • @scaling_mode_property: Optional atomic property to control the
  • upscaling. See drm_connector_attach_content_protection_property().

diff --git a/include/drm/drm_hdcp.h b/include/drm/drm_hdcp.h index 9457c7ec0d37..011f35e121a5 100644 --- a/include/drm/drm_hdcp.h +++ b/include/drm/drm_hdcp.h @@ -300,10 +300,16 @@ struct hdcp2_srm_header {

struct drm_device; struct drm_connector; +struct hdcp_topology_info;

bool drm_hdcp_ksvs_revocated(struct drm_device *dev, u8 *ksvs, u32 ksv_count); int drm_connector_attach_content_protection_property( struct drm_connector *connector, bool hdcp_content_type); void drm_hdcp_update_content_protection(struct drm_connector *connector, u64 val); +int drm_connector_attach_hdcp_topology_property(

• 		struct drm_connector *connector);
  

+int drm_connector_update_hdcp_topology_property(

• 		struct drm_connector *connector,
  

• 		const struct hdcp_topology_info *info);
  

#endif diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h index b359b5b71eb9..4349b614fa15 100644 --- a/include/drm/drm_mode_config.h +++ b/include/drm/drm_mode_config.h @@ -848,6 +848,12 @@ struct drm_mode_config { */ struct drm_property *hdcp_content_type_property;

• /**

• * @hdcp_topology_property: DRM BLOB property for hdcp downstream
  

• * topology information.
  

• */
  

• struct drm_property *hdcp_topology_property;
• /* dumb ioctl parameters */ uint32_t preferred_depth, prefer_shadow;

diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h index 8ac03351fdee..9d7cdfab4962 100644 --- a/include/uapi/drm/drm_mode.h +++ b/include/uapi/drm/drm_mode.h @@ -213,6 +213,43 @@ extern "C" { #define DRM_MODE_HDCP_CONTENT_TYPE0 0 #define DRM_MODE_HDCP_CONTENT_TYPE1 1

+#define DRM_MODE_HDCP_KSV_LEN 5 +#define DRM_MODE_HDCP_MAX_DEVICE_CNT 127 +#define DRM_MODE_HDCP14_IN_FORCE (1 << 0) +#define DRM_MODE_HDCP22_IN_FORCE (1 << 1)

+struct hdcp_topology_info {

• /* Version of HDCP authenticated (1.4/2.2) */
• __u32 ver_in_force;
• /* Applicable only for HDCP2.2 */
• __u32 content_type;
• /* KSV of immediate HDCP Sink. In Little-Endian Format. */
• __u8 bksv[DRM_MODE_HDCP_KSV_LEN];
• /* Whether Immediate HDCP sink is a repeater? */
• __u8 is_repeater;
• /* Depth received from immediate downstream repeater */
• __u8 depth;
• __u8 pad1;
• /* Device count received from immediate downstream repeater */
• __u32 device_count;
• /*

• * Max buffer required to hold ksv list received from immediate
  

• * repeater. In this array first device_count * DRM_MODE_HDCP_KSV_LEN
  

• * will hold the valid ksv bytes.
  

• * If authentication specification is
  

• *	HDCP1.4 - each KSV's Bytes will be in Little-Endian format.
  

• *	HDCP2.2 - each KSV's Bytes will be in Big-Endian format.
  

• */
  

• __u8 ksv_list[DRM_MODE_HDCP_KSV_LEN * DRM_MODE_HDCP_MAX_DEVICE_CNT];
• __u8 pad2[5];

+} __packed;

So I think we need userspace for this, but not sure where the discussions on that are right now. Is this feasible, or this and follow-up i915 patch more fyi and not for upstream? -Daniel

struct drm_mode_modeinfo { __u32 clock; __u16 hdisplay; -- 2.19.1