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Commit 0bb9c2b2 authored by Dhinakaran Pandiyan's avatar Dhinakaran Pandiyan Committed by Ville Syrjälä
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drm/dp/mst: Sideband message transaction to power up/down nodes 



The POWER_DOWN_PHY and POWER_UP_PHY sideband message transactions allow
the source to reqest any node in a mst path or a whole path to be
powered down or up. This allows drivers to target a specific sink in the
MST topology, an improvement over just power managing the imediate
downstream device. Secondly, since the request-reply protocol waits for an
ACK, we can be sure that a downstream sink has enough time to respond to a
power up/down request.

v2: Fix memory leak (Lyude)
Cc: Lyude <lyude@redhat.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: default avatarDhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170907001458.9399-1-dhinakaran.pandiyan@intel.com


Reviewed-by: default avatarLyude Paul <lyude@redhat.com>
Signed-off-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
parent 8a50b9bd

drivers/gpu/drm/drm_dp_mst_topology.c

+74 −0
Original line number Diff line number Diff line
@@ -294,6 +294,12 @@ static void drm_dp_encode_sideband_req(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_POWER_DOWN_PHY:

	case DP_POWER_UP_PHY:

		buf[idx] = (req->u.port_num.port_number & 0xf) << 4;

		idx++;

		break;

	}

	raw->cur_len = idx;

}
@@ -538,6 +544,21 @@ static bool drm_dp_sideband_parse_query_payload_ack(struct drm_dp_sideband_msg_r 
	return false;

}



static bool drm_dp_sideband_parse_power_updown_phy_ack(struct drm_dp_sideband_msg_rx *raw,

						       struct drm_dp_sideband_msg_reply_body *repmsg)

{

	int idx = 1;



	repmsg->u.port_number.port_number = (raw->msg[idx] >> 4) & 0xf;

	idx++;

	if (idx > raw->curlen) {

		DRM_DEBUG_KMS("power up/down phy parse length fail %d %d\n",

			      idx, raw->curlen);

		return false;

	}

	return true;

}



static bool drm_dp_sideband_parse_reply(struct drm_dp_sideband_msg_rx *raw,

					struct drm_dp_sideband_msg_reply_body *msg)

{
@@ -567,6 +588,9 @@ static bool drm_dp_sideband_parse_reply(struct drm_dp_sideband_msg_rx *raw, 
		return drm_dp_sideband_parse_enum_path_resources_ack(raw, msg);

	case DP_ALLOCATE_PAYLOAD:

		return drm_dp_sideband_parse_allocate_payload_ack(raw, msg);

	case DP_POWER_DOWN_PHY:

	case DP_POWER_UP_PHY:

		return drm_dp_sideband_parse_power_updown_phy_ack(raw, msg);

	default:

		DRM_ERROR("Got unknown reply 0x%02x\n", msg->req_type);

		return false;
@@ -693,6 +717,22 @@ static int build_allocate_payload(struct drm_dp_sideband_msg_tx *msg, int port_n 
	return 0;

}



static int build_power_updown_phy(struct drm_dp_sideband_msg_tx *msg,

				  int port_num, bool power_up)

{

	struct drm_dp_sideband_msg_req_body req;



	if (power_up)

		req.req_type = DP_POWER_UP_PHY;

	else

		req.req_type = DP_POWER_DOWN_PHY;



	req.u.port_num.port_number = port_num;

	drm_dp_encode_sideband_req(&req, msg);

	msg->path_msg = true;

	return 0;

}



static int drm_dp_mst_assign_payload_id(struct drm_dp_mst_topology_mgr *mgr,

					struct drm_dp_vcpi *vcpi)

{
@@ -1724,6 +1764,40 @@ static int drm_dp_payload_send_msg(struct drm_dp_mst_topology_mgr *mgr, 
	return ret;

}



int drm_dp_send_power_updown_phy(struct drm_dp_mst_topology_mgr *mgr,

				 struct drm_dp_mst_port *port, bool power_up)

{

	struct drm_dp_sideband_msg_tx *txmsg;

	int len, ret;



	port = drm_dp_get_validated_port_ref(mgr, port);

	if (!port)

		return -EINVAL;



	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);

	if (!txmsg) {

		drm_dp_put_port(port);

		return -ENOMEM;

	}



	txmsg->dst = port->parent;

	len = build_power_updown_phy(txmsg, port->port_num, power_up);

	drm_dp_queue_down_tx(mgr, txmsg);



	ret = drm_dp_mst_wait_tx_reply(port->parent, txmsg);

	if (ret > 0) {

		if (txmsg->reply.reply_type == 1)

			ret = -EINVAL;

		else

			ret = 0;

	}

	kfree(txmsg);

	drm_dp_put_port(port);



	return ret;

}

EXPORT_SYMBOL(drm_dp_send_power_updown_phy);



static int drm_dp_create_payload_step1(struct drm_dp_mst_topology_mgr *mgr,

				       int id,

				       struct drm_dp_payload *payload)

include/drm/drm_dp_mst_helper.h

+2 −0
Original line number Diff line number Diff line
@@ -631,5 +631,7 @@ int drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state *state, 
int drm_dp_atomic_release_vcpi_slots(struct drm_atomic_state *state,

				     struct drm_dp_mst_topology_mgr *mgr,

				     int slots);

int drm_dp_send_power_updown_phy(struct drm_dp_mst_topology_mgr *mgr,

				 struct drm_dp_mst_port *port, bool power_up);



#endif