From: Mykola Lysenko <mykola.lyse...@amd.com>

In case broadcast message received in UP request,
RAD cannot be used to identify message originator.
Message should be parsed, originator should be found
by GUID from parsed message.

Also reply with broadcast in case broadcast message
received (for now it is always broadcast)

Signed-off-by: Mykola Lysenko <Mykola.Lysenko at amd.com>
---
 drivers/gpu/drm/drm_dp_mst_topology.c | 95 +++++++++++++++++++++++++++++++----
 1 file changed, 84 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c 
b/drivers/gpu/drm/drm_dp_mst_topology.c
index 809959d56d78..3baa95c1b14b 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -1210,6 +1210,50 @@ out:
        return mstb;
 }

+static struct drm_dp_mst_branch *get_mst_branch_device_by_guid_helper(
+       struct drm_dp_mst_branch *mstb,
+       uint8_t *guid)
+{
+       struct drm_dp_mst_branch *found_mstb;
+       struct drm_dp_mst_port *port;
+
+       list_for_each_entry(port, &mstb->ports, next) {
+               if (!port->mstb)
+                       continue;
+
+               if (port->guid_valid && memcmp(port->guid, guid, 16) == 0)
+                       return port->mstb;
+
+               found_mstb = get_mst_branch_device_by_guid_helper(port->mstb, 
guid);
+
+               if (found_mstb)
+                       return found_mstb;
+       }
+
+       return NULL;
+}
+
+static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device_by_guid(
+       struct drm_dp_mst_topology_mgr *mgr,
+       uint8_t *guid)
+{
+       struct drm_dp_mst_branch *mstb;
+
+       /* find the port by iterating down */
+       mutex_lock(&mgr->lock);
+
+       if (mgr->guid_valid && memcmp(mgr->guid, guid, 16) == 0)
+               mstb = mgr->mst_primary;
+       else
+               mstb = get_mst_branch_device_by_guid_helper(mgr->mst_primary, 
guid);
+
+       if (mstb)
+               kref_get(&mstb->kref);
+
+       mutex_unlock(&mgr->lock);
+       return mstb;
+}
+
 static void drm_dp_check_and_send_link_address(struct drm_dp_mst_topology_mgr 
*mgr,
                                               struct drm_dp_mst_branch *mstb)
 {
@@ -1320,6 +1364,7 @@ static int set_hdr_from_dst_qlock(struct 
drm_dp_sideband_msg_hdr *hdr,
                                  struct drm_dp_sideband_msg_tx *txmsg)
 {
        struct drm_dp_mst_branch *mstb = txmsg->dst;
+       u8 req_type;

        /* both msg slots are full */
        if (txmsg->seqno == -1) {
@@ -1336,7 +1381,13 @@ static int set_hdr_from_dst_qlock(struct 
drm_dp_sideband_msg_hdr *hdr,
                        txmsg->seqno = 1;
                mstb->tx_slots[txmsg->seqno] = txmsg;
        }
-       hdr->broadcast = 0;
+
+       req_type = txmsg->msg[0] & 0x7f;
+       if (req_type == DP_CONNECTION_STATUS_NOTIFY ||
+               req_type == DP_RESOURCE_STATUS_NOTIFY)
+               hdr->broadcast = 1;
+       else
+               hdr->broadcast = 0;
        hdr->path_msg = txmsg->path_msg;
        hdr->lct = mstb->lct;
        hdr->lcr = mstb->lct - 1;
@@ -2145,28 +2196,50 @@ static int drm_dp_mst_handle_up_req(struct 
drm_dp_mst_topology_mgr *mgr)

        if (mgr->up_req_recv.have_eomt) {
                struct drm_dp_sideband_msg_req_body msg;
-               struct drm_dp_mst_branch *mstb;
+               struct drm_dp_mst_branch *mstb = NULL;
                bool seqno;
-               mstb = drm_dp_get_mst_branch_device(mgr,
-                                                   
mgr->up_req_recv.initial_hdr.lct,
-                                                   
mgr->up_req_recv.initial_hdr.rad);
-               if (!mstb) {
-                       DRM_DEBUG_KMS("Got MST reply from unknown device %d\n", 
mgr->up_req_recv.initial_hdr.lct);
-                       memset(&mgr->up_req_recv, 0, sizeof(struct 
drm_dp_sideband_msg_rx));
-                       return 0;
+
+               if (!mgr->up_req_recv.initial_hdr.broadcast) {
+                       mstb = drm_dp_get_mst_branch_device(mgr,
+                                                           
mgr->up_req_recv.initial_hdr.lct,
+                                                           
mgr->up_req_recv.initial_hdr.rad);
+                       if (!mstb) {
+                               DRM_DEBUG_KMS("Got MST reply from unknown 
device %d\n", mgr->up_req_recv.initial_hdr.lct);
+                               memset(&mgr->up_req_recv, 0, sizeof(struct 
drm_dp_sideband_msg_rx));
+                               return 0;
+                       }
                }

                seqno = mgr->up_req_recv.initial_hdr.seqno;
                drm_dp_sideband_parse_req(&mgr->up_req_recv, &msg);

                if (msg.req_type == DP_CONNECTION_STATUS_NOTIFY) {
-                       drm_dp_send_up_ack_reply(mgr, mstb, msg.req_type, 
seqno, false);
+                       drm_dp_send_up_ack_reply(mgr, mgr->mst_primary, 
msg.req_type, seqno, false);
+
+                       if (!mstb)
+                               mstb = 
drm_dp_get_mst_branch_device_by_guid(mgr, msg.u.conn_stat.guid);
+
+                       if (!mstb) {
+                               DRM_DEBUG_KMS("Got MST reply from unknown 
device %d\n", mgr->up_req_recv.initial_hdr.lct);
+                               memset(&mgr->up_req_recv, 0, sizeof(struct 
drm_dp_sideband_msg_rx));
+                               return 0;
+                       }
+
                        drm_dp_update_port(mstb, &msg.u.conn_stat);
                        DRM_DEBUG_KMS("Got CSN: pn: %d ldps:%d ddps: %d mcs: %d 
ip: %d pdt: %d\n", msg.u.conn_stat.port_number, 
msg.u.conn_stat.legacy_device_plug_status, 
msg.u.conn_stat.displayport_device_plug_status, 
msg.u.conn_stat.message_capability_status, msg.u.conn_stat.input_port, 
msg.u.conn_stat.peer_device_type);
                        (*mgr->cbs->hotplug)(mgr);

                } else if (msg.req_type == DP_RESOURCE_STATUS_NOTIFY) {
-                       drm_dp_send_up_ack_reply(mgr, mstb, msg.req_type, 
seqno, false);
+                       drm_dp_send_up_ack_reply(mgr, mgr->mst_primary, 
msg.req_type, seqno, false);
+                       if (!mstb)
+                               mstb = 
drm_dp_get_mst_branch_device_by_guid(mgr, msg.u.resource_stat.guid);
+
+                       if (!mstb) {
+                               DRM_DEBUG_KMS("Got MST reply from unknown 
device %d\n", mgr->up_req_recv.initial_hdr.lct);
+                               memset(&mgr->up_req_recv, 0, sizeof(struct 
drm_dp_sideband_msg_rx));
+                               return 0;
+                       }
+
                        DRM_DEBUG_KMS("Got RSN: pn: %d avail_pbn %d\n", 
msg.u.resource_stat.port_number, msg.u.resource_stat.available_pbn);
                }

-- 
2.1.4

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