[Intel-gfx] [PATCH v7 15/17] drm/mst: Add support for QUERY_STREAM_ENCRYPTION_STATUS MST sideband message

Anshuman Gupta anshuman.gupta at intel.com
Tue Jun 30 14:09:30 UTC 2020


On 2020-06-23 at 21:29:05 +0530, Sean Paul wrote:
Hi Sean,
I am new to DP MST stuff, I am looking to DP MST spec DP v1.2a.
I have looked the entire series, i will take up this opportunity to review
the series from HDCP over DP MST POV.
I think theoretically this series should work or Gen12 as well, as DP MST streams
are getting encrypted by QUERY_STREAM_ENCRYPTION_STATUS reply tranaction msg
(generating Stream State Signature L’).
I will test this on Gen12 H/W with DP MST support and will provide my inputs.

Meanwhile while going through DP MST v1.2a specs(Page 262) came to know about 
a DP irq vector LINK_SERVICE_IRQ_VECTOR_ESI0 (02005h),
Bit 2 : STREAM_STATUS_CHANGED.
When this bit set to ‘1’ indicates the source must re-check the Stream Status
with the QUERY_STREAM_ENCRYPTION_STATUS message.
Currently i feel this irq support is missing, do we require to support
above IRQ vector for DP MST stream encryption.

Thanks,
Anshuman Gupta.

> From: Sean Paul <seanpaul at chromium.org>
> 
> Used to query whether an MST stream is encrypted or not.
> 
> Signed-off-by: Sean Paul <seanpaul at chromium.org>
> 
> Link: https://patchwork.freedesktop.org/patch/msgid/20200218220242.107265-14-sean@poorly.run #v4
> Link: https://patchwork.freedesktop.org/patch/msgid/20200305201236.152307-15-sean@poorly.run #v5
> Link: https://patchwork.freedesktop.org/patch/msgid/20200429195502.39919-15-sean@poorly.run #v6
> 
> Changes in v4:
> -Added to the set
> Changes in v5:
> -None
> Changes in v6:
> -Use FIELD_PREP to generate request buffer bitfields (Lyude)
> -Add mst selftest and dump/decode_sideband_req for QSES (Lyude)
> Changes in v7:
> -None
> ---
>  drivers/gpu/drm/drm_dp_mst_topology.c         | 142 ++++++++++++++++++
>  .../drm/selftests/test-drm_dp_mst_helper.c    |  17 +++
>  include/drm/drm_dp_helper.h                   |   3 +
>  include/drm/drm_dp_mst_helper.h               |  44 ++++++
>  4 files changed, 206 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
> index b2f5a84b4cfb..fc68478eaeb4 100644
> --- a/drivers/gpu/drm/drm_dp_mst_topology.c
> +++ b/drivers/gpu/drm/drm_dp_mst_topology.c
> @@ -20,11 +20,13 @@
>   * OF THIS SOFTWARE.
>   */
>  
> +#include <linux/bitfield.h>
>  #include <linux/delay.h>
>  #include <linux/errno.h>
>  #include <linux/i2c.h>
>  #include <linux/init.h>
>  #include <linux/kernel.h>
> +#include <linux/random.h>
>  #include <linux/sched.h>
>  #include <linux/seq_file.h>
>  #include <linux/iopoll.h>
> @@ -419,6 +421,22 @@ drm_dp_encode_sideband_req(const struct drm_dp_sideband_msg_req_body *req,
>  		memcpy(&buf[idx], req->u.i2c_write.bytes, req->u.i2c_write.num_bytes);
>  		idx += req->u.i2c_write.num_bytes;
>  		break;
> +	case DP_QUERY_STREAM_ENC_STATUS: {
> +		const struct drm_dp_query_stream_enc_status *msg;
> +
> +		msg = &req->u.enc_status;
> +		buf[idx] = msg->stream_id;
> +		idx++;
> +		memcpy(&buf[idx], msg->client_id, sizeof(msg->client_id));
> +		idx += sizeof(msg->client_id);
> +		buf[idx] = 0;
> +		buf[idx] |= FIELD_PREP(GENMASK(1, 0), msg->stream_event);
> +		buf[idx] |= msg->valid_stream_event ? BIT(2) : 0;
> +		buf[idx] |= FIELD_PREP(GENMASK(4, 3), msg->stream_behavior);
> +		buf[idx] |= msg->valid_stream_behavior ? BIT(5) : 0;
> +		idx++;
> +		}
> +		break;
>  	}
>  	raw->cur_len = idx;
>  }
> @@ -547,6 +565,20 @@ drm_dp_decode_sideband_req(const struct drm_dp_sideband_msg_tx *raw,
>  				return -ENOMEM;
>  		}
>  		break;
> +	case DP_QUERY_STREAM_ENC_STATUS:
> +		req->u.enc_status.stream_id = buf[idx++];
> +		for (i = 0; i < sizeof(req->u.enc_status.client_id); i++)
> +			req->u.enc_status.client_id[i] = buf[idx++];
> +
> +		req->u.enc_status.stream_event = FIELD_GET(GENMASK(1, 0),
> +							   buf[idx]);
> +		req->u.enc_status.valid_stream_event = FIELD_GET(BIT(2),
> +							 	 buf[idx]);
> +		req->u.enc_status.stream_behavior = FIELD_GET(GENMASK(4, 3),
> +							      buf[idx]);
> +		req->u.enc_status.valid_stream_behavior = FIELD_GET(BIT(5),
> +								    buf[idx]);
> +		break;
>  	}
>  
>  	return 0;
> @@ -625,6 +657,16 @@ drm_dp_dump_sideband_msg_req_body(const struct drm_dp_sideband_msg_req_body *req
>  		  req->u.i2c_write.num_bytes, req->u.i2c_write.num_bytes,
>  		  req->u.i2c_write.bytes);
>  		break;
> +	case DP_QUERY_STREAM_ENC_STATUS:
> +		P("stream_id=%u client_id=%*ph stream_event=%x "
> +		  "valid_event=%d stream_behavior=%x valid_behavior=%d",
> +		  req->u.enc_status.stream_id,
> +		  (int)ARRAY_SIZE(req->u.enc_status.client_id),
> +		  req->u.enc_status.client_id, req->u.enc_status.stream_event,
> +		  req->u.enc_status.valid_stream_event,
> +		  req->u.enc_status.stream_behavior,
> +		  req->u.enc_status.valid_stream_behavior);
> +		break;
>  	default:
>  		P("???\n");
>  		break;
> @@ -925,6 +967,34 @@ static bool drm_dp_sideband_parse_power_updown_phy_ack(struct drm_dp_sideband_ms
>  	return true;
>  }
>  
> +static bool
> +drm_dp_sideband_parse_query_stream_enc_status(
> +				struct drm_dp_sideband_msg_rx *raw,
> +				struct drm_dp_sideband_msg_reply_body *repmsg)
> +{
> +	struct drm_dp_query_stream_enc_status_ack_reply *reply;
> +
> +	reply = &repmsg->u.enc_status;
> +
> +	reply->stream_id = raw->msg[3];
> +
> +	reply->reply_signed = raw->msg[2] & BIT(0);
> +
> +	reply->hdcp_1x_device_present = raw->msg[2] & BIT(3);
> +	reply->hdcp_2x_device_present = raw->msg[2] & BIT(4);
> +
> +	reply->query_capable_device_present = raw->msg[2] & BIT(5);
> +	reply->legacy_device_present = raw->msg[2] & BIT(6);
> +	reply->unauthorizable_device_present = raw->msg[2] & BIT(7);
> +
> +	reply->auth_completed = !!(raw->msg[1] & BIT(3));
> +	reply->encryption_enabled = !!(raw->msg[1] & BIT(4));
> +	reply->repeater_present = !!(raw->msg[1] & BIT(5));
> +	reply->state = (raw->msg[1] & GENMASK(7, 6)) >> 6;
> +
> +	return true;
> +}
> +
>  static bool drm_dp_sideband_parse_reply(struct drm_dp_sideband_msg_rx *raw,
>  					struct drm_dp_sideband_msg_reply_body *msg)
>  {
> @@ -959,6 +1029,8 @@ static bool drm_dp_sideband_parse_reply(struct drm_dp_sideband_msg_rx *raw,
>  		return drm_dp_sideband_parse_power_updown_phy_ack(raw, msg);
>  	case DP_CLEAR_PAYLOAD_ID_TABLE:
>  		return true; /* since there's nothing to parse */
> +	case DP_QUERY_STREAM_ENC_STATUS:
> +		return drm_dp_sideband_parse_query_stream_enc_status(raw, msg);
>  	default:
>  		DRM_ERROR("Got unknown reply 0x%02x (%s)\n", msg->req_type,
>  			  drm_dp_mst_req_type_str(msg->req_type));
> @@ -1109,6 +1181,25 @@ static void build_power_updown_phy(struct drm_dp_sideband_msg_tx *msg,
>  	msg->path_msg = true;
>  }
>  
> +static int
> +build_query_stream_enc_status(struct drm_dp_sideband_msg_tx *msg, u8 stream_id,
> +			      u8 *q_id)
> +{
> +	struct drm_dp_sideband_msg_req_body req;
> +
> +	req.req_type = DP_QUERY_STREAM_ENC_STATUS;
> +	req.u.enc_status.stream_id = stream_id;
> +	memcpy(req.u.enc_status.client_id, q_id,
> +	       sizeof(req.u.enc_status.client_id));
> +	req.u.enc_status.stream_event = 0;
> +	req.u.enc_status.valid_stream_event = false;
> +	req.u.enc_status.stream_behavior = 0;
> +	req.u.enc_status.valid_stream_behavior = false;
> +
> +	drm_dp_encode_sideband_req(&req, msg);
> +	return 0;
> +}
> +
>  static int drm_dp_mst_assign_payload_id(struct drm_dp_mst_topology_mgr *mgr,
>  					struct drm_dp_vcpi *vcpi)
>  {
> @@ -3137,6 +3228,57 @@ int drm_dp_send_power_updown_phy(struct drm_dp_mst_topology_mgr *mgr,
>  }
>  EXPORT_SYMBOL(drm_dp_send_power_updown_phy);
>  
> +int drm_dp_send_query_stream_enc_status(struct drm_dp_mst_topology_mgr *mgr,
> +		struct drm_dp_mst_port *port,
> +		struct drm_dp_query_stream_enc_status_ack_reply *status)
> +{
> +	struct drm_dp_sideband_msg_tx *txmsg;
> +	u8 nonce[7];
> +	int len, ret;
> +
> +	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
> +	if (!txmsg)
> +		return -ENOMEM;
> +
> +	port = drm_dp_mst_topology_get_port_validated(mgr, port);
> +	if (!port) {
> +		ret = -EINVAL;
> +		goto out_get_port;
> +	}
> +
> +	get_random_bytes(nonce, sizeof(nonce));
> +
> +	/*
> +	 * "Source device targets the QUERY_STREAM_ENCRYPTION_STATUS message
> +	 *  transaction at the MST Branch device directly connected to the
> +	 *  Source"
> +	 */
> +	txmsg->dst = mgr->mst_primary;
> +
> +	len = build_query_stream_enc_status(txmsg, port->vcpi.vcpi, nonce);
> +
> +	drm_dp_queue_down_tx(mgr, txmsg);
> +
> +	ret = drm_dp_mst_wait_tx_reply(mgr->mst_primary, txmsg);
> +	if (ret < 0) {
> +		goto out;
> +	} else if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
> +		DRM_DEBUG_KMS("query encryption status nak received\n");
> +		ret = -ENXIO;
> +		goto out;
> +	}
> +
> +	ret = 0;
> +	memcpy(status, &txmsg->reply.u.enc_status, sizeof(*status));
> +
> +out:
> +	drm_dp_mst_topology_put_port(port);
> +out_get_port:
> +	kfree(txmsg);
> +	return ret;
> +}
> +EXPORT_SYMBOL(drm_dp_send_query_stream_enc_status);
> +
>  static int drm_dp_create_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
>  				       int id,
>  				       struct drm_dp_payload *payload)
> diff --git a/drivers/gpu/drm/selftests/test-drm_dp_mst_helper.c b/drivers/gpu/drm/selftests/test-drm_dp_mst_helper.c
> index bd990d178765..1d696ec001cf 100644
> --- a/drivers/gpu/drm/selftests/test-drm_dp_mst_helper.c
> +++ b/drivers/gpu/drm/selftests/test-drm_dp_mst_helper.c
> @@ -5,6 +5,8 @@
>  
>  #define PREFIX_STR "[drm_dp_mst_helper]"
>  
> +#include <linux/random.h>
> +
>  #include <drm/drm_dp_mst_helper.h>
>  #include <drm/drm_print.h>
>  
> @@ -237,6 +239,21 @@ int igt_dp_mst_sideband_msg_req_decode(void *unused)
>  	in.u.i2c_write.bytes = data;
>  	DO_TEST();
>  
> +	in.req_type = DP_QUERY_STREAM_ENC_STATUS;
> +	in.u.enc_status.stream_id = 1;
> +	DO_TEST();
> +	get_random_bytes(in.u.enc_status.client_id,
> +			 sizeof(in.u.enc_status.client_id));
> +	DO_TEST();
> +	in.u.enc_status.stream_event = 3;
> +	DO_TEST();
> +	in.u.enc_status.valid_stream_event = 0;
> +	DO_TEST();
> +	in.u.enc_status.stream_behavior = 3;
> +	DO_TEST();
> +	in.u.enc_status.valid_stream_behavior = 1;
> +	DO_TEST();
> +
>  #undef DO_TEST
>  	return 0;
>  }
> diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
> index e47dc22ebf50..e2d2df5e869e 100644
> --- a/include/drm/drm_dp_helper.h
> +++ b/include/drm/drm_dp_helper.h
> @@ -1108,6 +1108,9 @@
>  #define DP_POWER_DOWN_PHY		0x25
>  #define DP_SINK_EVENT_NOTIFY		0x30
>  #define DP_QUERY_STREAM_ENC_STATUS	0x38
> +#define  DP_QUERY_STREAM_ENC_STATUS_STATE_NO_EXIST	0
> +#define  DP_QUERY_STREAM_ENC_STATUS_STATE_INACTIVE	1
> +#define  DP_QUERY_STREAM_ENC_STATUS_STATE_ACTIVE	2
>  
>  /* DP 1.2 MST sideband reply types */
>  #define DP_SIDEBAND_REPLY_ACK		0x00
> diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h
> index 8b9eb4db3381..371eef8798ad 100644
> --- a/include/drm/drm_dp_mst_helper.h
> +++ b/include/drm/drm_dp_mst_helper.h
> @@ -313,6 +313,34 @@ struct drm_dp_remote_i2c_write_ack_reply {
>  	u8 port_number;
>  };
>  
> +struct drm_dp_query_stream_enc_status_ack_reply {
> +	/* Bit[23:16]- Stream Id */
> +	u8 stream_id;
> +
> +	/* Bit[15]- Signed */
> +	bool reply_signed;
> +
> +	/* Bit[10:8]- Stream Output Sink Type */
> +	bool unauthorizable_device_present;
> +	bool legacy_device_present;
> +	bool query_capable_device_present;
> +
> +	/* Bit[12:11]- Stream Output CP Type */
> +	bool hdcp_1x_device_present;
> +	bool hdcp_2x_device_present;
> +
> +	/* Bit[4]- Stream Authentication */
> +	bool auth_completed;
> +
> +	/* Bit[3]- Stream Encryption */
> +	bool encryption_enabled;
> +
> +	/* Bit[2]- Stream Repeater Function Present */
> +	bool repeater_present;
> +
> +	/* Bit[1:0]- Stream State */
> +	u8 state;
> +};
>  
>  #define DRM_DP_MAX_SDP_STREAMS 16
>  struct drm_dp_allocate_payload {
> @@ -374,6 +402,15 @@ struct drm_dp_remote_i2c_write {
>  	u8 *bytes;
>  };
>  
> +struct drm_dp_query_stream_enc_status {
> +	u8 stream_id;
> +	u8 client_id[7];	/* 56-bit nonce */
> +	u8 stream_event;
> +	bool valid_stream_event;
> +	u8 stream_behavior;
> +	u8 valid_stream_behavior;
> +};
> +
>  /* this covers ENUM_RESOURCES, POWER_DOWN_PHY, POWER_UP_PHY */
>  struct drm_dp_port_number_req {
>  	u8 port_number;
> @@ -422,6 +459,8 @@ struct drm_dp_sideband_msg_req_body {
>  
>  		struct drm_dp_remote_i2c_read i2c_read;
>  		struct drm_dp_remote_i2c_write i2c_write;
> +
> +		struct drm_dp_query_stream_enc_status enc_status;
>  	} u;
>  };
>  
> @@ -444,6 +483,8 @@ struct drm_dp_sideband_msg_reply_body {
>  		struct drm_dp_remote_i2c_read_ack_reply remote_i2c_read_ack;
>  		struct drm_dp_remote_i2c_read_nak_reply remote_i2c_read_nack;
>  		struct drm_dp_remote_i2c_write_ack_reply remote_i2c_write_ack;
> +
> +		struct drm_dp_query_stream_enc_status_ack_reply enc_status;
>  	} u;
>  };
>  
> @@ -808,6 +849,9 @@ drm_dp_atomic_release_vcpi_slots(struct drm_atomic_state *state,
>  				 struct drm_dp_mst_port *port);
>  int drm_dp_send_power_updown_phy(struct drm_dp_mst_topology_mgr *mgr,
>  				 struct drm_dp_mst_port *port, bool power_up);
> +int drm_dp_send_query_stream_enc_status(struct drm_dp_mst_topology_mgr *mgr,
> +		struct drm_dp_mst_port *port,
> +		struct drm_dp_query_stream_enc_status_ack_reply *status);
>  int __must_check drm_dp_mst_atomic_check(struct drm_atomic_state *state);
>  
>  void drm_dp_mst_get_port_malloc(struct drm_dp_mst_port *port);
> -- 
> Sean Paul, Software Engineer, Google / Chromium OS
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx


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