[PATCH v3 16/40] misc/mei/hdcp: Verify M_prime

[Ramalingam C]

Request to ME to verify the M_Prime received from the HDCP sink.

ME FW will calculate the M and compare with M_prime received
as part of RepeaterAuth_Stream_Ready, which is HDCP2.2 protocol msg.

On successful completion of this stage, downstream propagation of
the stream management info is completed.

v2:
  Rebased.
v3:
  cldev is passed as first parameter [Tomas]
  Redundant comments and cast are removed [Tomas]

Signed-off-by: Ramalingam C <ramalingam.c at intel.com>
---
 drivers/misc/mei/hdcp/mei_hdcp.c | 79 ++++++++++++++++++++++++++++++++++++++++
 include/linux/mei_hdcp.h         |  8 ++++
 2 files changed, 87 insertions(+)

diff --git a/drivers/misc/mei/hdcp/mei_hdcp.c b/drivers/misc/mei/hdcp/mei_hdcp.c
index 64fcecfa5b10..68eb5267a8e7 100644
--- a/drivers/misc/mei/hdcp/mei_hdcp.c
+++ b/drivers/misc/mei/hdcp/mei_hdcp.c
@@ -553,6 +553,85 @@ mei_repeater_check_flow_prepare_ack(struct mei_cl_device *cldev,
 }
 EXPORT_SYMBOL(mei_repeater_check_flow_prepare_ack);
 
+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];
+		}
+	}
+}
+
+/**
+ * mei_verify_mprime:
+ *	Function to verify mprime.
+ *
+ * @cldev		: Pointer for mei client device
+ * @data		: Intel HW specific Data
+ * @stream_ready	: pointer for RepeaterAuth_Stream_Ready message.
+ *
+ * Returns 0 on Success, <0 on Failure
+ */
+int mei_verify_mprime(struct mei_cl_device *cldev, struct mei_hdcp_data *data,
+		      struct hdcp2_rep_stream_ready *stream_ready)
+{
+	struct wired_cmd_repeater_auth_stream_req_in
+					verify_mprime_in = { { 0 } };
+	struct wired_cmd_repeater_auth_stream_req_out
+					verify_mprime_out = { { 0 } };
+	struct device *dev;
+	ssize_t byte;
+
+	if (!stream_ready || !data)
+		return -EINVAL;
+
+	dev = &cldev->dev;
+
+	verify_mprime_in.header.api_version = HDCP_API_VERSION;
+	verify_mprime_in.header.command_id = WIRED_REPEATER_AUTH_STREAM_REQ;
+	verify_mprime_in.header.status = ME_HDCP_STATUS_SUCCESS;
+	verify_mprime_in.header.buffer_len =
+			WIRED_CMD_BUF_LEN_REPEATER_AUTH_STREAM_REQ_MIN_IN;
+
+	verify_mprime_in.port.integrated_port_type = data->port_type;
+	verify_mprime_in.port.physical_port = data->port;
+
+	memcpy(verify_mprime_in.m_prime, stream_ready->m_prime,
+	       HDCP_2_2_MPRIME_LEN);
+	reverse_endianness((u8 *)&verify_mprime_in.seq_num_m,
+			   HDCP_2_2_SEQ_NUM_LEN, (u8 *)&data->seq_num_m);
+	memcpy(verify_mprime_in.streams, data->streams,
+	       (data->k * sizeof(struct hdcp2_streamid_type)));
+
+	verify_mprime_in.k = __swab16(data->k);
+
+	byte = mei_cldev_send(cldev, (u8 *)&verify_mprime_in,
+			      sizeof(verify_mprime_in));
+	if (byte < 0) {
+		dev_dbg(dev, "mei_cldev_send failed. %d\n", (int)byte);
+		return byte;
+	}
+
+	byte = mei_cldev_recv(cldev, (u8 *)&verify_mprime_out,
+			      sizeof(verify_mprime_out));
+	if (byte < 0) {
+		dev_dbg(dev, "mei_cldev_recv failed. %d\n", (int)byte);
+		return byte;
+	}
+
+	if (verify_mprime_out.header.status != ME_HDCP_STATUS_SUCCESS) {
+		dev_dbg(dev, "ME cmd 0x%08X failed. status: 0x%X\n",
+			WIRED_REPEATER_AUTH_STREAM_REQ,
+			verify_mprime_out.header.status);
+		return -1;
+	}
+	return 0;
+}
+EXPORT_SYMBOL(mei_verify_mprime);
+
 void mei_cldev_state_notify_clients(struct mei_cl_device *cldev, bool enabled)
 {
 	if (enabled)
diff --git a/include/linux/mei_hdcp.h b/include/linux/mei_hdcp.h
index 46e2dc295d03..dbc216e13f97 100644
--- a/include/linux/mei_hdcp.h
+++ b/include/linux/mei_hdcp.h
@@ -134,6 +134,8 @@ mei_repeater_check_flow_prepare_ack(struct mei_cl_device *cldev,
 				    struct hdcp2_rep_send_receiverid_list
 							*rep_topology,
 				    struct hdcp2_rep_send_ack *rep_send_ack);
+int mei_verify_mprime(struct mei_cl_device *cldev, struct mei_hdcp_data *data,
+		      struct hdcp2_rep_stream_ready *stream_ready);
 #else
 static int mei_cldev_register_notify(struct notifier_block *nb)
 {
@@ -201,5 +203,11 @@ mei_repeater_check_flow_prepare_ack(struct mei_cl_device *cldev,
 {
 	return -ENODEV;
 }
+static inline
+int mei_verify_mprime(struct mei_cl_device *cldev, struct mei_hdcp_data *data,
+		      struct hdcp2_rep_stream_ready *stream_ready)
+{
+	return -ENODEV;
+}
 #endif /* defined (CONFIG_INTEL_MEI_HDCP) */
 #endif /* defined (_LINUX_MEI_HDCP_H) */
-- 
2.7.4