On Wed, 2017-09-06 at 11:40 -0400, Lyude Paul wrote:
> On Tue, 2017-09-05 at 18:26 -0700, Dhinakaran Pandiyan wrote:
> > 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 <lyude@xxxxxxxxxx>
> > Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> > Cc: Harry Wentland <harry.wentland@xxxxxxx>
> > Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@xxxxxxxxx>
> > ---
> > 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;
> if (!port), then you leak memory by not freeing txmsg
Right, I'll fix that up in the next version. Thanks!
> > +
> > + 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
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