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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: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170907001458.9399-1-dhinakaran.pandiyan@intel.com
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
This commit is contained in:
Dhinakaran Pandiyan 2017-09-06 17:14:58 -07:00 committed by Ville Syrjälä
parent 8a50b9bd56
commit 0bb9c2b27f
2 changed files with 76 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

74
drivers/gpu/drm/drm_dp_mst_topology.c
View File

@ -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 @@ fail_len:
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 @@ fail_put:
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)

2
include/drm/drm_dp_mst_helper.h
View File

@ -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