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().
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
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandi...@intel.com>
---
drivers/gpu/drm/drm_dp_mst_topology.c | 75 +++++++++++++++++++++++++++++++++++
include/drm/drm_dp_mst_helper.h | 6 +++
2 files changed, 81 insertions(+)
diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c
b/drivers/gpu/drm/drm_dp_mst_topology.c
index a891c36..93de257 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -2498,6 +2498,81 @@ static int drm_dp_init_vcpi(struct
drm_dp_mst_topology_mgr *mgr,
}
/**
+ * 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
+ * @port: port to release the vcpi slots for
+ *
+ * RETURNS:
+ * Number of slots released from the atomic state for this port
+ */
+int drm_dp_atomic_release_vcpi_slots(struct drm_atomic_state *state,
+ struct drm_dp_mst_topology_mgr *mgr,
+ struct drm_dp_mst_port *port)
+{
+ struct drm_dp_mst_topology_state *topology_state;
+ int curr_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;
+
+ curr_slots = port->vcpi.num_slots;
+ topology_state->avail_slots += curr_slots;
+ DRM_DEBUG_KMS("vcpi slots released=%d, avail=%d\n",
+ curr_slots, topology_state->avail_slots);
+
+ drm_dp_put_port(port);
+ return curr_slots;
+}
+EXPORT_SYMBOL(drm_dp_atomic_release_vcpi_slots);
+
+/**
* drm_dp_mst_allocate_vcpi() - Allocate a virtual channel
* @mgr: manager for this port
* @port: port to allocate a virtual channel for.
diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h
index 0b371df..64e7dac 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,
+ struct drm_dp_mst_port *port);
#endif
--
2.7.4
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