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 --- drivers/gpu/drm/drm_dp_mst_topology.c | 75 +++++++++++++++++++++++++++++++++++ 1 file changed, 75 insertions(+) (limited to 'drivers/gpu/drm/drm_dp_mst_topology.c') diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index d3fc7e4e85b7..0ad0baae5c7e 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -2936,6 +2936,69 @@ 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. Also, drm_atomic_get_private_obj_state() expects the caller + * to care of the locking, so warn if don't hold the connection_mutex. + * + * 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) +{ + struct drm_device *dev = mgr->dev; + + WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex)); + 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 +3043,15 @@ 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 +3072,9 @@ 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); -- cgit v1.2.1 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 +++++++++++++++++++++++++++++++++++ 1 file changed, 75 insertions(+) (limited to 'drivers/gpu/drm/drm_dp_mst_topology.c') 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 -- cgit v1.2.1 From 992d38cc787d353aba8b0e13d37a719a3431db79 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Sat, 13 May 2017 11:52:00 +0100 Subject: drm/dp: Read the tx msg state once after checking for an event Both as an exercise to document that we are reading the state outside of the appropriate mutex and to ensure that we only read the value once before the multiple comparisons, use READ_ONCE. Signed-off-by: Chris Wilson Signed-off-by: Daniel Vetter Link: http://patchwork.freedesktop.org/patch/msgid/20170513105201.17658-1-chris@chris-wilson.co.uk --- drivers/gpu/drm/drm_dp_mst_topology.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'drivers/gpu/drm/drm_dp_mst_topology.c') diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index d1cbb9c8f806..3bdd314f02b1 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -737,16 +737,16 @@ static void drm_dp_mst_put_payload_id(struct drm_dp_mst_topology_mgr *mgr, static bool check_txmsg_state(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_sideband_msg_tx *txmsg) { - bool ret; + unsigned int state; /* * All updates to txmsg->state are protected by mgr->qlock, and the two * cases we check here are terminal states. For those the barriers * provided by the wake_up/wait_event pair are enough. */ - ret = (txmsg->state == DRM_DP_SIDEBAND_TX_RX || - txmsg->state == DRM_DP_SIDEBAND_TX_TIMEOUT); - return ret; + state = READ_ONCE(txmsg->state); + return (state == DRM_DP_SIDEBAND_TX_RX || + state == DRM_DP_SIDEBAND_TX_TIMEOUT); } static int drm_dp_mst_wait_tx_reply(struct drm_dp_mst_branch *mstb, -- cgit v1.2.1 From 68e989dc044346a7941370c48a96a64f42a36be1 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Sat, 13 May 2017 11:52:01 +0100 Subject: drm/dp: Wait up all outstanding tx waiters As we can have multiple tx in the queue, with individual waiters, make sure that all are woken when any state changes (so that we are sure the right owner of the txmsg is woken). Signed-off-by: Chris Wilson Signed-off-by: Daniel Vetter Link: http://patchwork.freedesktop.org/patch/msgid/20170513105201.17658-2-chris@chris-wilson.co.uk --- drivers/gpu/drm/drm_dp_mst_topology.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'drivers/gpu/drm/drm_dp_mst_topology.c') diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index 3bdd314f02b1..222eb1a8549b 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -855,7 +855,7 @@ static void drm_dp_destroy_mst_branch_device(struct kref *kref) mutex_unlock(&mstb->mgr->qlock); if (wake_tx) - wake_up(&mstb->mgr->tx_waitq); + wake_up_all(&mstb->mgr->tx_waitq); kref_put(kref, drm_dp_free_mst_branch_device); } @@ -1510,7 +1510,7 @@ static void process_single_down_tx_qlock(struct drm_dp_mst_topology_mgr *mgr) if (txmsg->seqno != -1) txmsg->dst->tx_slots[txmsg->seqno] = NULL; txmsg->state = DRM_DP_SIDEBAND_TX_TIMEOUT; - wake_up(&mgr->tx_waitq); + wake_up_all(&mgr->tx_waitq); } } @@ -2258,7 +2258,7 @@ static int drm_dp_mst_handle_down_rep(struct drm_dp_mst_topology_mgr *mgr) mstb->tx_slots[slot] = NULL; mutex_unlock(&mgr->qlock); - wake_up(&mgr->tx_waitq); + wake_up_all(&mgr->tx_waitq); } return ret; } -- cgit v1.2.1