From 3f3353b7e1218d208507bc52688cacb4ff893c28 Mon Sep 17 00:00:00 2001 From: "Pandiyan, Dhinakaran" Date: Thu, 20 Apr 2017 22:51:31 -0700 Subject: drm/dp: Introduce MST topology state to track available link bandwidth 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. v3: WARN_ON() if connection_mutex is not held (Archit) v2: Included kernel doc, moved state initialization and switched to kmemdup() for allocation (Daniel) Cc: Daniel Vetter Cc: Maarten Lankhorst Cc: Archit Taneja Cc: Chris Wilson Cc: Harry Wentland Reviewed-by: Maarten Lankhorst Reviewed-by: Harry Wentland Signed-off-by: Dhinakaran Pandiyan Signed-off-by: Maarten Lankhorst Link: http://patchwork.freedesktop.org/patch/msgid/1492753893-3748-3-git-send-email-dhinakaran.pandiyan@intel.com --- include/drm/drm_dp_mst_helper.h | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'include/drm/drm_dp_mst_helper.h') diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h index 5b024764666c..0b371dffed00 100644 --- a/include/drm/drm_dp_mst_helper.h +++ b/include/drm/drm_dp_mst_helper.h @@ -24,6 +24,7 @@ #include #include +#include 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 * @@ -480,6 +487,16 @@ 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 -- cgit v1.2.3 From edb1ed1ab7d314e114de84003f763da34c0f34c0 Mon Sep 17 00:00:00 2001 From: "Pandiyan, Dhinakaran" Date: Thu, 20 Apr 2017 22:51:32 -0700 Subject: drm/dp: Add DP MST helpers to atomically find and release vcpi slots drm_dp_atomic_find_vcpi_slots() should be called from ->atomic_check() to check there are sufficient vcpi slots for a mode and to add that to the state. This should be followed by a call to drm_dp_mst_allocate_vcpi() in ->atomic_commit() to initialize a struct vcpi for the port. drm_dp_atomic_release_vcpi_slots() should be called from ->atomic_check() to release a port's vcpi slot allocation from the state. Drivers that do not make use of this atomic helper are expected to call drm_dp_find_vcpi_slots() instead before calling drm_dp_mst_allocate_vcpi(). v3: drm_dp_atomic_release_vcpi_slots() now needs to know how many slots to release as we may not have a valid reference to port. v2: Added checks for verifying the port reference is valid Moved get_mst_topology_state() into the helpers (Daniel) Changed find_vcpi_slots() to not depend on current allocation Cc: Daniel Vetter Cc: Maarten Lankhorst Cc: Archit Taneja Cc: Chris Wilson Cc: Harry Wentland Reviewed-by: Harry Wentland Reviewed-by: Maarten Lankhorst Signed-off-by: Dhinakaran Pandiyan Signed-off-by: Maarten Lankhorst Link: http://patchwork.freedesktop.org/patch/msgid/1492753893-3748-4-git-send-email-dhinakaran.pandiyan@intel.com --- drivers/gpu/drm/drm_dp_mst_topology.c | 75 +++++++++++++++++++++++++++++++++++ include/drm/drm_dp_mst_helper.h | 6 +++ 2 files changed, 81 insertions(+) (limited to 'include/drm/drm_dp_mst_helper.h') diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index 0ad0baae5c7e..d1cbb9c8f806 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -2497,6 +2497,81 @@ static int drm_dp_init_vcpi(struct drm_dp_mst_topology_mgr *mgr, return 0; } +/** + * drm_dp_atomic_find_vcpi_slots() - Find and add vcpi slots to the state + * @state: global atomic state + * @mgr: MST topology manager for the port + * @port: port to find vcpi slots for + * @pbn: bandwidth required for the mode in PBN + * + * RETURNS: + * Total slots in the atomic state assigned for this port or error + */ +int drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state *state, + struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_port *port, int pbn) +{ + struct drm_dp_mst_topology_state *topology_state; + int req_slots; + + topology_state = drm_atomic_get_mst_topology_state(state, mgr); + if (topology_state == NULL) + return -ENOMEM; + + port = drm_dp_get_validated_port_ref(mgr, port); + if (port == NULL) + return -EINVAL; + req_slots = DIV_ROUND_UP(pbn, mgr->pbn_div); + DRM_DEBUG_KMS("vcpi slots req=%d, avail=%d\n", + req_slots, topology_state->avail_slots); + + if (req_slots > topology_state->avail_slots) { + drm_dp_put_port(port); + return -ENOSPC; + } + + topology_state->avail_slots -= req_slots; + DRM_DEBUG_KMS("vcpi slots avail=%d", topology_state->avail_slots); + + drm_dp_put_port(port); + return req_slots; +} +EXPORT_SYMBOL(drm_dp_atomic_find_vcpi_slots); + +/** + * drm_dp_atomic_release_vcpi_slots() - Release allocated vcpi slots + * @state: global atomic state + * @mgr: MST topology manager for the port + * @slots: number of vcpi slots to release + * + * RETURNS: + * 0 if @slots were added back to &drm_dp_mst_topology_state->avail_slots or + * negative error code + */ +int drm_dp_atomic_release_vcpi_slots(struct drm_atomic_state *state, + struct drm_dp_mst_topology_mgr *mgr, + int slots) +{ + struct drm_dp_mst_topology_state *topology_state; + + topology_state = drm_atomic_get_mst_topology_state(state, mgr); + if (topology_state == NULL) + return -ENOMEM; + + /* We cannot rely on port->vcpi.num_slots to update + * topology_state->avail_slots as the port may not exist if the parent + * branch device was unplugged. This should be fixed by tracking + * per-port slot allocation in drm_dp_mst_topology_state instead of + * depending on the caller to tell us how many slots to release. + */ + topology_state->avail_slots += slots; + DRM_DEBUG_KMS("vcpi slots released=%d, avail=%d\n", + slots, topology_state->avail_slots); + + return 0; +} +EXPORT_SYMBOL(drm_dp_atomic_release_vcpi_slots); + /** * drm_dp_mst_allocate_vcpi() - Allocate a virtual channel * @mgr: manager for this port diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h index 0b371dffed00..177ab6f86855 100644 --- a/include/drm/drm_dp_mst_helper.h +++ b/include/drm/drm_dp_mst_helper.h @@ -615,5 +615,11 @@ 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); +int drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state *state, + struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_port *port, int pbn); +int drm_dp_atomic_release_vcpi_slots(struct drm_atomic_state *state, + struct drm_dp_mst_topology_mgr *mgr, + int slots); #endif -- cgit v1.2.3