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.
Cc: Lyude <ly...@redhat.com>
Cc: Ville Syrjälä <ville.syrj...@linux.intel.com>
Cc: Harry Wentland <harry.wentl...@amd.com>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandi...@intel.com>
---
drivers/gpu/drm/drm_dp_mst_topology.c | 73 +++++++++++++++++++++++++++++++++++
include/drm/drm_dp_mst_helper.h | 2 +
2 files changed, 75 insertions(+)
diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c
b/drivers/gpu/drm/drm_dp_mst_topology.c
index 41b492f99955..a9f12708a046 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -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 +544,22 @@ 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 +589,9 @@ 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 +718,22 @@ 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 +1765,38 @@ 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;
+
+ txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
+ if (!txmsg)
+ return -ENOMEM;
+
+ port = drm_dp_get_validated_port_ref(mgr, port);
+ if (!port)
+ return -EINVAL;
+
+ 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 0;
+}
+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)
diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h
index d55abb75f29a..7f78d26a0766 100644
--- a/include/drm/drm_dp_mst_helper.h
+++ b/include/drm/drm_dp_mst_helper.h
@@ -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
--
2.11.0
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