[PATCH 29/43] drm/i915: Implement HDCP2.2 repeater authentication

Ramalingam C
2018-02-14T14:20:55Z

Implements the HDCP2.2 repeaters authentication steps such as verifying
the downstream topology and sending stream management information.

Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
---
drivers/gpu/drm/i915/intel_hdcp.c | 133 ++++++++++++++++++++++++++++++++++++++
1 file changed, 133 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_hdcp.c b/drivers/gpu/drm/i915/intel_hdcp.c
index 64276f180e45..0cd637dd3f6b 100644
--- a/drivers/gpu/drm/i915/intel_hdcp.c
+++ b/drivers/gpu/drm/i915/intel_hdcp.c
@@ -1153,6 +1153,133 @@ static int hdcp2_session_key_exchange(struct intel_hdcp *hdcp)
return 0;
}

+/*
+ * Lib endianness functions are aligned for 16/32/64 bits. Since here sequence
+ * num is 24bits developed a small conversion function.
+ */
+static inline void reverse_endianness(u8 *dest, size_t dst_sz, u8 *src)
+{
+ u32 index;
+
+ if (dest != NULL && dst_sz != 0) {
+ for (index = 0; index < dst_sz && index < sizeof(u32);
+ index++) {
+ dest[dst_sz - index - 1] = src[index];
+ }
+ }
+}
+
+static int hdcp2_propagate_stream_management_info(struct intel_hdcp *hdcp)
+{
+ struct intel_digital_port *intel_dig_port =
+ conn_to_dig_port(hdcp->connector);
+ union {
+ struct hdcp2_rep_stream_manage stream_manage;
+ struct hdcp2_rep_stream_ready stream_ready;
+ } msgs;
+ const struct intel_hdcp2_shim *shim = hdcp->hdcp2_shim;
+ int ret;
+
+ /* Prepare RepeaterAuth_Stream_Manage msg */
+ msgs.stream_manage.msg_id = REP_STREAM_MANAGE;
+ reverse_endianness(msgs.stream_manage.seq_num_m, HDCP_SEQ_NUM_LEN,
+ (u8 *)&hdcp->seq_num_m);
+
+ /* K no of streams is fixed as 1. Stored as big-endian. */
+ msgs.stream_manage.k = __swab16(1);
+
+ /* For HDMI this is forced to be 0x0. For DP SST also this is 0x0. */
+ msgs.stream_manage.streams[0].stream_id = 0;
+ msgs.stream_manage.streams[0].stream_type = hdcp->content_type;
+
+ /* Send it to Repeater */
+ ret = shim->write_msg(intel_dig_port, &msgs.stream_manage,
+ sizeof(msgs.stream_manage));
+ if (ret < 0)
+ return ret;
+
+ ret = shim->read_msg(intel_dig_port, REP_STREAM_READY,
+ &msgs.stream_ready, sizeof(msgs.stream_ready));
+ if (ret < 0)
+ return ret;
+
+ hdcp->mei_hdcp_data->seq_num_m = hdcp->seq_num_m;
+ hdcp->mei_hdcp_data->streams[0].stream_type = hdcp->content_type;
+
+ ret = hdcp2_verify_mprime(hdcp, &msgs.stream_ready);
+ if (ret < 0)
+ return ret;
+
+ hdcp->seq_num_m++;
+
+ if (hdcp->seq_num_m > HDCP_2_2_SEQ_NUM_MAX) {
+ DRM_DEBUG_KMS("seq_num_m roll over.\n");
+ return -1;
+ }
+ return 0;
+}
+
+static int hdcp2_authenticate_repeater_topology(struct intel_hdcp *hdcp)
+{
+ struct intel_digital_port *intel_dig_port =
+ conn_to_dig_port(hdcp->connector);
+ union {
+ struct hdcp2_rep_send_receiverid_list recvid_list;
+ struct hdcp2_rep_send_ack rep_ack;
+ } msgs;
+ const struct intel_hdcp2_shim *shim = hdcp->hdcp2_shim;
+ union hdcp2_rx_info *rx_info;
+ uint32_t seq_num_v;
+ int ret;
+
+ ret = shim->read_msg(intel_dig_port, REP_SEND_RECVID_LIST,
+ &msgs.recvid_list, sizeof(msgs.recvid_list));
+ if (ret < 0)
+ return ret;
+
+ rx_info = &msgs.recvid_list.rx_info;
+
+ if (rx_info->fields.max_cascade_exceeded ||
+ rx_info->fields.max_devs_exceeded) {
+ DRM_DEBUG_KMS("Topology Max Size Exceeded\n");
+ return -1;
+ }
+
+ /* Converting and Storing the seq_num_v to local variable as DWORD */
+ reverse_endianness((u8 *)&seq_num_v, HDCP_SEQ_NUM_LEN,
+ msgs.recvid_list.seq_num_v);
+
+ if (seq_num_v < hdcp->seq_num_v) {
+ /* Roll over of the seq_num_v from repeater. Reauthenticate. */
+ DRM_DEBUG_KMS("Seq_num_v roll over.\n");
+ return -1;
+ }
+
+ ret = hdcp2_verify_rep_topology_prepare_ack(hdcp, &msgs.recvid_list,
+ &msgs.rep_ack);
+ if (ret < 0)
+ return ret;
+
+ hdcp->seq_num_v = seq_num_v;
+ ret = shim->write_msg(intel_dig_port, &msgs.rep_ack,
+ sizeof(msgs.rep_ack));
+ if (ret < 0)
+ return ret;
+
+ return 0;
+}
+
+static int hdcp2_authenticate_repeater(struct intel_hdcp *hdcp)
+{
+ int ret;
+
+ ret = hdcp2_authenticate_repeater_topology(hdcp);
+ if (ret < 0)
+ return ret;
+
+ return hdcp2_propagate_stream_management_info(hdcp);
+}
+
static int hdcp2_authenticate_sink(struct intel_hdcp *hdcp)
{
struct intel_digital_port *intel_dig_port =
@@ -1194,6 +1321,12 @@ static int hdcp2_authenticate_sink(struct intel_hdcp *hdcp)
sizeof(stream_type_msg));
if (ret < 0)
return ret;
+ } else if (hdcp->is_repeater) {
+ ret = hdcp2_authenticate_repeater(hdcp);
+ if (ret < 0) {
+ DRM_DEBUG_KMS("Repeater Auth Failed. Err: %d\n", ret);
+ return ret;
+ }
}

hdcp->mei_hdcp_data->streams[0].stream_type = hdcp->content_type;