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().
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@xxxxxxxxx>
---
drivers/gpu/drm/drm_dp_mst_topology.c | 43 +++++++++++++++++++++++++++++++++++
include/drm/drm_dp_mst_helper.h | 5 ++++
2 files changed, 48 insertions(+)
diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index 1be19e1..737d61f 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -2501,6 +2501,49 @@ static int drm_dp_init_vcpi(struct drm_dp_mst_topology_mgr *mgr,
}
/**
+ * drm_dp_atomic_release_vcpi_slots() - Release allocated vcpi slots from the state
+ * @topology_state: MST topology state
+ * @port: port to release the vcpi slots for
+ */
+int drm_dp_atomic_release_vcpi_slots(struct drm_dp_mst_topology_state *topology_state,
+ struct drm_dp_mst_port *port)
+{
+ int alloc = drm_dp_mst_get_vcpi_slots(topology_state->mgr, port);
+
+ topology_state->avail_slots += alloc;
+ DRM_DEBUG_KMS("vcpi slots released=%d, avail=%d\n",
+ alloc, topology_state->avail_slots);
+ return alloc;
+}
+EXPORT_SYMBOL(drm_dp_atomic_release_vcpi_slots);
+
+/**
+ * drm_dp_atomic_find_vcpi_slots() - Find and add vcpi slots to the state
+ * @topology_state: MST topology state
+ * @port: port to find vcpi slots for
+ * @pbn: bandwidth required for the mode in PBN
+ */
+int drm_dp_atomic_find_vcpi_slots(struct drm_dp_mst_topology_state *topology_state,
+ struct drm_dp_mst_port *port, int pbn)
+{
+ int num_slots, curr_alloc;
+ struct drm_dp_mst_topology_mgr *mgr = topology_state->mgr;
+
+ num_slots = DIV_ROUND_UP(pbn, mgr->pbn_div);
+ curr_alloc = drm_dp_mst_get_vcpi_slots(mgr, port);
+ DRM_DEBUG_KMS("vcpi slots new=%d, curr=%d, avail=%d\n",
+ num_slots, curr_alloc, topology_state->avail_slots);
+
+ if (num_slots - curr_alloc > topology_state->avail_slots)
+ return -ENOSPC;
+
+ topology_state->avail_slots -= (num_slots - curr_alloc);
+ DRM_DEBUG_KMS("vcpi slots avail=%d", topology_state->avail_slots);
+ return num_slots;
+}
+EXPORT_SYMBOL(drm_dp_atomic_find_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 0a9bf20..90395d8 100644
--- a/include/drm/drm_dp_mst_helper.h
+++ b/include/drm/drm_dp_mst_helper.h
@@ -609,4 +609,9 @@ 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_dp_mst_topology_state *topology_state,
+ struct drm_dp_mst_port *port, int pbn);
+int drm_dp_atomic_release_vcpi_slots(struct drm_dp_mst_topology_state *topology_state,
+ struct drm_dp_mst_port *port);
+
#endif
--
2.7.4
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