drm/msm/dp: introduce dp_mst_drm for MST stream management

Add a dp_mst_drm layer to manage DP MST streams with a clear ownership
model between encoder, panel and connector.

Each MST stream is represented by a dedicated drm_encoder. At modeset
initialization time, one (encoder, dp_panel) pair is created per
stream_id and remains fixed for the lifetime of the driver. The
dp_panel thus carries a stable stream context, including stream_id
and pixel mapping.

MST connectors are created and destroyed dynamically on hotplug and
are attached to a dp_panel through atomic routing. During an atomic
commit, connectors are associated with encoders via
atomic_best_encoder(), forming a temporary binding for the duration
of the commit.

Encoder helper callbacks drive the MST stream lifecycle, including
timeslot allocation, link enable/disable and payload programming.

A per-MST-instance lock serializes operations on shared link state
across multiple streams.

Signed-off-by: Abhinav Kumar <[email protected]>
Signed-off-by: Yongxing Mou <[email protected]>
---
 drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c |   6 +
 drivers/gpu/drm/msm/dp/dp_display.c     |   9 ++
 drivers/gpu/drm/msm/dp/dp_display.h     |   2 +
 drivers/gpu/drm/msm/dp/dp_mst_drm.c     | 245 ++++++++++++++++++++++++++++++++
 drivers/gpu/drm/msm/msm_drv.h           |   7 +
 5 files changed, 269 insertions(+)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c 
b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
index b32ecd5b0777..ac5dc844fead 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
@@ -696,6 +696,12 @@ static int _dpu_kms_initialize_displayport(struct 
drm_device *dev,
                                        DPU_ERROR("encoder init failed for dp 
mst display\n");
                                        return PTR_ERR(encoder);
                                }
+
+                               rc = 
msm_dp_mst_attach_encoder(priv->kms->dp[i], encoder);
+                               if (rc) {
+                                       DPU_ERROR("dp_mst attach_encoder 
failed, rc = %d\n", rc);
+                                       return rc;
+                               }
                        }
                }
        }
diff --git a/drivers/gpu/drm/msm/dp/dp_display.c 
b/drivers/gpu/drm/msm/dp/dp_display.c
index fc9c1e3e57ab..6eac390af2e0 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -601,6 +601,15 @@ struct msm_dp_panel *msm_dp_display_get_panel(struct 
msm_dp *msm_dp_display,
        return dp_panel;
 }
 
+void msm_dp_display_set_link_info(struct msm_dp *msm_dp_display,
+                                 struct msm_dp_link_info *dst)
+{
+       struct msm_dp_display_private *dp =
+               container_of(msm_dp_display, struct msm_dp_display_private, 
msm_dp_display);
+
+       memcpy(dst, &dp->panel->link_info, sizeof(*dst));
+}
+
 static void msm_dp_display_deinit_sub_modules(struct msm_dp_display_private 
*dp)
 {
        msm_dp_audio_put(dp->audio);
diff --git a/drivers/gpu/drm/msm/dp/dp_display.h 
b/drivers/gpu/drm/msm/dp/dp_display.h
index a185819ec57e..fb6bdd372b52 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.h
+++ b/drivers/gpu/drm/msm/dp/dp_display.h
@@ -63,4 +63,6 @@ void msm_dp_display_unprepare(struct msm_dp *dp);
 
 struct msm_dp_panel *msm_dp_display_get_panel(struct msm_dp *msm_dp_display,
                                              enum msm_dp_stream_id stream_id);
+void msm_dp_display_set_link_info(struct msm_dp *msm_dp_display,
+                                 struct msm_dp_link_info *dst);
 #endif /* _DP_DISPLAY_H_ */
diff --git a/drivers/gpu/drm/msm/dp/dp_mst_drm.c 
b/drivers/gpu/drm/msm/dp/dp_mst_drm.c
index 78b8dffe111b..6a77fdef85e9 100644
--- a/drivers/gpu/drm/msm/dp/dp_mst_drm.c
+++ b/drivers/gpu/drm/msm/dp/dp_mst_drm.c
@@ -4,18 +4,259 @@
  */
 
 #include <drm/drm_edid.h>
+#include <drm/drm_fixed.h>
+#include <drm/drm_atomic_helper.h>
 #include <drm/display/drm_dp_mst_helper.h>
 
 #include "dp_mst_drm.h"
 #include "dp_panel.h"
+#include "dpu_encoder.h"
+
+#define to_dp_mst_connector(x) \
+               container_of((x), struct msm_dp_mst_connector, connector)
+
+struct msm_dp_mst_encoder {
+       struct drm_encoder *enc;
+       int stream_id;
+       struct msm_dp_panel *dp_panel;
+};
+
+struct msm_dp_mst_connector {
+       struct drm_connector connector;
+       struct drm_dp_mst_port *mst_port;
+       struct msm_dp_mst *dp_mst;
+};
+
 
 struct msm_dp_mst {
        struct drm_dp_mst_topology_mgr mst_mgr;
+       struct msm_dp_mst_encoder mst_encoders[DP_STREAM_MAX];
        struct msm_dp *msm_dp;
        struct drm_dp_aux *dp_aux;
        u32 max_streams;
+       struct mutex mst_lock;
+       struct msm_dp_link_info link_info;
 };
 
+static struct msm_dp_panel *msm_dp_mst_panel_from_encoder(struct msm_dp_mst 
*mst,
+                                                         struct drm_encoder 
*enc)
+{
+       int i;
+
+       for (i = 0; i < mst->max_streams; i++) {
+               if (mst->mst_encoders[i].enc == enc)
+                       return mst->mst_encoders[i].dp_panel;
+       }
+       return NULL;
+}
+
+static void msm_dp_mst_update_timeslots(struct msm_dp_mst *mst,
+                                       struct msm_dp_panel *panel,
+                                       struct drm_dp_mst_atomic_payload 
*payload)
+{
+       if (payload->vc_start_slot < 0)
+               msm_dp_display_set_stream_info(mst->msm_dp, panel, 1, 0, 0);
+       else
+               msm_dp_display_set_stream_info(mst->msm_dp, panel,
+                                              payload->vc_start_slot,
+                                              payload->time_slots, 
payload->pbn);
+
+       drm_dbg_kms(mst->msm_dp->drm_dev,
+                   "[MST] stream:%u timeslots vc_start:%d slots:%d pbn:%d\n",
+                   panel->stream_id, payload->vc_start_slot,
+                   payload->time_slots, payload->pbn);
+}
+
+static void msm_dp_mst_stream_enable(struct drm_encoder *encoder,
+                                    struct drm_atomic_commit *state)
+{
+       struct drm_connector *connector =
+               drm_atomic_get_new_connector_for_encoder(state, encoder);
+       struct msm_dp_mst_connector *mst_conn = to_dp_mst_connector(connector);
+       struct msm_dp_mst *mst = mst_conn->dp_mst;
+       struct msm_dp *dp_display = mst->msm_dp;
+       struct msm_dp_panel *panel = msm_dp_mst_panel_from_encoder(mst, 
encoder);
+       struct drm_dp_mst_port *port = mst_conn->mst_port;
+       struct drm_dp_mst_topology_state *mst_state =
+               drm_atomic_get_new_mst_topology_state(state, &mst->mst_mgr);
+       struct drm_dp_mst_atomic_payload *payload =
+               drm_atomic_get_mst_payload_state(mst_state, port);
+       int rc;
+
+       panel->connector = connector;
+
+       guard(mutex)(&mst->mst_lock);
+
+       rc = msm_dp_display_set_mode_helper(dp_display, state, encoder, panel);
+       if (rc) {
+               drm_err(dp_display->drm_dev,
+                       "[MST] stream:%u set_mode failed rc=%d\n", 
panel->stream_id, rc);
+               goto out;
+       }
+
+       rc = msm_dp_display_prepare_link(dp_display);
+       if (rc) {
+               drm_err(dp_display->drm_dev,
+                       "[MST] stream:%u prepare_link failed rc=%d\n", 
panel->stream_id, rc);
+               msm_dp_display_unprepare(dp_display);
+               goto out;
+       }
+
+       drm_dp_mst_update_slots(mst_state, DP_CAP_ANSI_8B10B);
+
+       rc = drm_dp_add_payload_part1(&mst->mst_mgr, mst_state, payload);
+       if (rc) {
+               drm_err(dp_display->drm_dev,
+                       "[MST] payload allocation failure for conn:%d\n", 
connector->base.id);
+               msm_dp_display_unprepare(dp_display);
+               goto out;
+       }
+
+       msm_dp_mst_update_timeslots(mst, panel, payload);
+
+       msm_dp_display_enable_helper(dp_display, panel);
+
+       drm_dp_check_act_status(&mst->mst_mgr);
+
+       drm_dp_add_payload_part2(&mst->mst_mgr, payload);
+
+out:
+       drm_connector_get(connector);
+}
+
+static void msm_dp_mst_stream_disable(struct drm_encoder *encoder,
+                                     struct drm_atomic_commit *state)
+{
+       struct drm_connector *connector = 
drm_atomic_get_old_connector_for_encoder(state, encoder);
+       struct msm_dp_mst_connector *mst_conn = to_dp_mst_connector(connector);
+       struct msm_dp_mst *mst = mst_conn->dp_mst;
+       struct msm_dp_panel *panel = msm_dp_mst_panel_from_encoder(mst, 
encoder);
+       struct drm_dp_mst_topology_state *old_mst_state =
+               drm_atomic_get_old_mst_topology_state(state, &mst->mst_mgr);
+       struct drm_dp_mst_topology_state *new_mst_state =
+               drm_atomic_get_new_mst_topology_state(state, &mst->mst_mgr);
+       struct drm_dp_mst_atomic_payload *old_payload =
+               drm_atomic_get_mst_payload_state(old_mst_state, 
mst_conn->mst_port);
+       struct drm_dp_mst_atomic_payload *new_payload =
+               drm_atomic_get_mst_payload_state(new_mst_state, 
mst_conn->mst_port);
+
+       guard(mutex)(&mst->mst_lock);
+
+       drm_dp_remove_payload_part1(&mst->mst_mgr, new_mst_state, new_payload);
+
+       drm_dp_remove_payload_part2(&mst->mst_mgr, new_mst_state, old_payload, 
new_payload);
+
+       msm_dp_mst_update_timeslots(mst, panel, new_payload);
+
+       msm_dp_display_disable_helper(mst->msm_dp, panel);
+
+       drm_dp_check_act_status(&mst->mst_mgr);
+}
+
+static void msm_dp_mst_stream_post_disable(struct drm_encoder *encoder,
+                                          struct drm_atomic_commit *state)
+{
+       struct drm_connector *connector = 
drm_atomic_get_old_connector_for_encoder(state, encoder);
+       struct msm_dp_mst_connector *mst_conn = to_dp_mst_connector(connector);
+       struct msm_dp_mst *mst = mst_conn->dp_mst;
+       struct msm_dp_panel *panel = msm_dp_mst_panel_from_encoder(mst, 
encoder);
+
+       guard(mutex)(&mst->mst_lock);
+
+       msm_dp_display_atomic_post_disable_helper(mst->msm_dp, panel);
+
+       if (!mst->msm_dp->mst_active)
+               msm_dp_display_unprepare(mst->msm_dp);
+
+       panel->connector = NULL;
+
+       drm_connector_put(connector);
+}
+
+static int msm_dp_mst_enc_atomic_check(struct drm_encoder *enc,
+                                      struct drm_crtc_state *crtc_state,
+                                      struct drm_connector_state *conn_state)
+{
+       struct msm_dp_mst_connector *mst_conn = 
to_dp_mst_connector(conn_state->connector);
+       struct msm_dp_mst *mst = mst_conn->dp_mst;
+       struct drm_dp_mst_topology_state *mst_state;
+       int bpp, pbn, slots;
+
+       if (!conn_state->crtc)
+               return 0;
+
+       if (!drm_atomic_crtc_needs_modeset(crtc_state) || !crtc_state->active)
+               return 0;
+
+       bpp = (conn_state->connector->display_info.bpc * 3) ?: 24; /* fallback: 
assume 8bpc */
+       pbn = drm_dp_calc_pbn_mode(crtc_state->mode.clock, bpp << 4);
+
+       mst_state = drm_atomic_get_mst_topology_state(crtc_state->state, 
&mst->mst_mgr);
+       if (IS_ERR(mst_state))
+               return PTR_ERR(mst_state);
+
+       if (!dfixed_trunc(mst_state->pbn_div)) {
+               mst_state->pbn_div =
+                       drm_dp_get_vc_payload_bw(mst->link_info.rate,
+                                                mst->link_info.num_lanes);
+       }
+
+       slots = drm_dp_atomic_find_time_slots(crtc_state->state, &mst->mst_mgr,
+                                             mst_conn->mst_port, pbn);
+       if (slots < 0)
+               return slots;
+
+       return 0;
+}
+
+static void msm_dp_mst_enc_atomic_enable(struct drm_encoder *enc,
+                                        struct drm_atomic_commit *state)
+{
+       msm_dp_mst_stream_enable(enc, state);
+       dpu_encoder_phys_enable(enc, state);
+}
+
+static void msm_dp_mst_enc_atomic_disable(struct drm_encoder *enc,
+                                         struct drm_atomic_commit *state)
+{
+       msm_dp_mst_stream_disable(enc, state);
+       dpu_encoder_phys_disable(enc, state);
+       msm_dp_mst_stream_post_disable(enc, state);
+}
+
+static const struct drm_encoder_helper_funcs msm_dp_mst_encoder_helper_funcs = 
{
+       .atomic_check    = msm_dp_mst_enc_atomic_check,
+       .atomic_mode_set = dpu_encoder_atomic_mode_set,
+       .atomic_enable   = msm_dp_mst_enc_atomic_enable,
+       .atomic_disable  = msm_dp_mst_enc_atomic_disable,
+};
+
+int msm_dp_mst_attach_encoder(struct msm_dp *dp_display, struct drm_encoder 
*encoder)
+{
+       struct msm_dp_mst *mst = dp_display->msm_dp_mst;
+       struct msm_dp_panel *dp_panel;
+       int i;
+
+       for (i = 0; i < mst->max_streams; i++) {
+               if (!mst->mst_encoders[i].enc)
+                       break;
+       }
+
+       dp_panel = msm_dp_display_get_panel(dp_display, i);
+       if (!dp_panel) {
+               drm_err(dp_display->drm_dev,
+                       "[MST] failed to allocate panel for stream %d\n", i);
+               return -ENOMEM;
+       }
+
+       mst->mst_encoders[i].enc = encoder;
+       mst->mst_encoders[i].stream_id = i;
+       mst->mst_encoders[i].dp_panel = dp_panel;
+       drm_encoder_helper_add(encoder, &msm_dp_mst_encoder_helper_funcs);
+
+       return 0;
+}
+
 int msm_dp_mst_display_set_mgr_state(struct msm_dp *dp_display, bool state)
 {
        struct msm_dp_mst *mst = dp_display->msm_dp_mst;
@@ -27,6 +268,9 @@ int msm_dp_mst_display_set_mgr_state(struct msm_dp 
*dp_display, bool state)
                        "[MST] failed to set topology mgr state to %d rc:%d\n", 
state, rc);
        }
 
+       if (state)
+               msm_dp_display_set_link_info(dp_display, &mst->link_info);
+
        drm_dbg_kms(dp_display->drm_dev, "[MST] set_mgr_state state:%d\n", 
state);
        return rc;
 }
@@ -55,6 +299,7 @@ int msm_dp_mst_init(struct msm_dp *dp_display, u32 
max_streams, struct drm_dp_au
                return ret;
        }
 
+       mutex_init(&mst->mst_lock);
        dp_display->msm_dp_mst = mst;
        return 0;
 }
diff --git a/drivers/gpu/drm/msm/msm_drv.h b/drivers/gpu/drm/msm/msm_drv.h
index f71200a790f3..854dd08eede2 100644
--- a/drivers/gpu/drm/msm/msm_drv.h
+++ b/drivers/gpu/drm/msm/msm_drv.h
@@ -358,6 +358,8 @@ bool msm_dp_needs_periph_flush(const struct msm_dp 
*dp_display,
 bool msm_dp_wide_bus_available(const struct msm_dp *dp_display);
 int msm_dp_get_mst_max_stream(struct msm_dp *dp_display);
 int msm_dp_mst_register(struct msm_dp *dp_display);
+int msm_dp_mst_attach_encoder(struct msm_dp *dp_display, struct drm_encoder 
*encoder);
+
 #else
 static inline int __init msm_dp_register(void)
 {
@@ -384,6 +386,11 @@ static inline int msm_dp_mst_register(struct msm_dp 
*dp_display)
        return -EINVAL;
 }
 
+static inline int msm_dp_mst_attach_encoder(struct msm_dp *dp_display, struct 
drm_encoder *encoder)
+{
+       return -EINVAL;
+}
+
 static inline void msm_dp_snapshot(struct msm_disp_state *disp_state, struct 
msm_dp *dp_display)
 {
 }

-- 
2.43.0

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