Link bandwidth is shared between multiple display streams in DP MST configurations. The DP MST topology manager structure maintains the shared link bandwidth for a primary link directly connected to the GPU. For atomic modesetting drivers, checking if there is sufficient link bandwidth for a mode needs to be done during the atomic_check phase to avoid failed modesets. Let's encapsulate the available link bw information in a private state structure so that bw can be allocated and released atomically for each of the ports sharing the primary link.
v2: Included kernel doc, moved state initialization and switched to kmemdup() for allocation (Daniel)
Signed-off-by: Dhinakaran Pandiyan dhinakaran.pandiyan@intel.com --- drivers/gpu/drm/drm_dp_mst_topology.c | 71 +++++++++++++++++++++++++++++++++++ include/drm/drm_dp_mst_helper.h | 20 ++++++++++ 2 files changed, 91 insertions(+)
diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index 37482b7..a891c36 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -2936,6 +2936,65 @@ static void drm_dp_destroy_connector_work(struct work_struct *work) (*mgr->cbs->hotplug)(mgr); }
+void *drm_dp_mst_duplicate_state(struct drm_atomic_state *state, void *obj) +{ + struct drm_dp_mst_topology_mgr *mgr = obj; + struct drm_dp_mst_topology_state *new_mst_state; + + if (WARN_ON(!mgr->state)) + return NULL; + + new_mst_state = kmemdup(mgr->state, sizeof(*new_mst_state), GFP_KERNEL); + if (new_mst_state) + new_mst_state->state = state; + return new_mst_state; +} + +void drm_dp_mst_swap_state(void *obj, void **obj_state_ptr) +{ + struct drm_dp_mst_topology_mgr *mgr = obj; + struct drm_dp_mst_topology_state **topology_state_ptr; + + topology_state_ptr = (struct drm_dp_mst_topology_state **)obj_state_ptr; + + mgr->state->state = (*topology_state_ptr)->state; + swap(*topology_state_ptr, mgr->state); + mgr->state->state = NULL; +} + +void drm_dp_mst_destroy_state(void *obj_state) +{ + kfree(obj_state); +} + +static const struct drm_private_state_funcs mst_state_funcs = { + .duplicate_state = drm_dp_mst_duplicate_state, + .swap_state = drm_dp_mst_swap_state, + .destroy_state = drm_dp_mst_destroy_state, +}; + +/** + * drm_atomic_get_mst_topology_state: get MST topology state + * + * @state: global atomic state + * @mgr: MST topology manager, also the private object in this case + * + * This function wraps drm_atomic_get_priv_obj_state() passing in the MST atomic + * state vtable so that the private object state returned is that of a MST + * topology object. + * + * RETURNS: + * + * The MST topology state or error pointer. + */ +struct drm_dp_mst_topology_state *drm_atomic_get_mst_topology_state(struct drm_atomic_state *state, + struct drm_dp_mst_topology_mgr *mgr) +{ + return drm_atomic_get_private_obj_state(state, mgr, + &mst_state_funcs); +} +EXPORT_SYMBOL(drm_atomic_get_mst_topology_state); + /** * drm_dp_mst_topology_mgr_init - initialise a topology manager * @mgr: manager struct to initialise @@ -2980,6 +3039,15 @@ int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr, if (test_calc_pbn_mode() < 0) DRM_ERROR("MST PBN self-test failed\n");
+ mgr->state = kzalloc(sizeof(*mgr->state), GFP_KERNEL); + if (mgr->state == NULL) + return -ENOMEM; + mgr->state->mgr = mgr; + + /* max. time slots - one slot for MTP header */ + mgr->state->avail_slots = 63; + mgr->funcs = &mst_state_funcs; + return 0; } EXPORT_SYMBOL(drm_dp_mst_topology_mgr_init); @@ -3000,6 +3068,9 @@ void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr) mutex_unlock(&mgr->payload_lock); mgr->dev = NULL; mgr->aux = NULL; + kfree(mgr->state); + mgr->state = NULL; + mgr->funcs = NULL; } EXPORT_SYMBOL(drm_dp_mst_topology_mgr_destroy);
diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h index 5b02476..0b371df 100644 --- a/include/drm/drm_dp_mst_helper.h +++ b/include/drm/drm_dp_mst_helper.h @@ -24,6 +24,7 @@
#include <linux/types.h> #include <drm/drm_dp_helper.h> +#include <drm/drm_atomic.h>
struct drm_dp_mst_branch;
@@ -403,6 +404,12 @@ struct drm_dp_payload { int vcpi; };
+struct drm_dp_mst_topology_state { + int avail_slots; + struct drm_atomic_state *state; + struct drm_dp_mst_topology_mgr *mgr; +}; + /** * struct drm_dp_mst_topology_mgr - DisplayPort MST manager * @@ -481,6 +488,16 @@ struct drm_dp_mst_topology_mgr { int pbn_div;
/** + * @state: State information for topology manager + */ + struct drm_dp_mst_topology_state *state; + + /** + * @funcs: Atomic helper callbacks + */ + const struct drm_private_state_funcs *funcs; + + /** * @qlock: protects @tx_msg_downq, the &drm_dp_mst_branch.txslost and * &drm_dp_sideband_msg_tx.state once they are queued */ @@ -596,4 +613,7 @@ void drm_dp_mst_dump_topology(struct seq_file *m,
void drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr *mgr); int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr); +struct drm_dp_mst_topology_state *drm_atomic_get_mst_topology_state(struct drm_atomic_state *state, + struct drm_dp_mst_topology_mgr *mgr); + #endif