8b/10b encoding format requires to reserve the first slot for recording metadata. Real data transmission starts from the second slot, with a total of available 63 slots available.
In 128b/132b encoding format, metadata is transmitted separately in LLCP packet before MTP. Real data transmission starts from the first slot, with a total of 64 slots available.
Update the slot information after link detect.
Signed-off-by: Fangzhi Zuo Jerry.Zuo@amd.com --- drivers/gpu/drm/drm_dp_mst_topology.c | 48 ++++++++++++++++++++++----- include/drm/drm_dp_mst_helper.h | 8 +++++ 2 files changed, 47 insertions(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index 42a0c6888c33..577ed4224778 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -3382,7 +3382,7 @@ int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr) struct drm_dp_payload req_payload; struct drm_dp_mst_port *port; int i, j; - int cur_slots = 1; + int cur_slots = mgr->first_link_start_slot;
mutex_lock(&mgr->payload_lock); for (i = 0; i < mgr->max_payloads; i++) { @@ -4302,8 +4302,13 @@ int drm_dp_find_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr,
num_slots = DIV_ROUND_UP(pbn, mgr->pbn_div);
- /* max. time slots - one slot for MTP header */ - if (num_slots > 63) + /** + * first_link_total_avail_slots: max. time slots + * first slot reserved for MTP header in 8b/10b, + * but not required for 128b/132b + */ + + if (num_slots > mgr->first_link_total_avail_slots) return -ENOSPC; return num_slots; } @@ -4314,8 +4319,12 @@ static int drm_dp_init_vcpi(struct drm_dp_mst_topology_mgr *mgr, { int ret;
- /* max. time slots - one slot for MTP header */ - if (slots > 63) + /** + * first_link_total_avail_slots: max. time slots + * first slot reserved for MTP header in 8b/10b, + * but not required for 128b/132b + */ + if (slots > mgr->first_link_total_avail_slots) return -ENOSPC;
vcpi->pbn = pbn; @@ -4488,6 +4497,25 @@ int drm_dp_atomic_release_vcpi_slots(struct drm_atomic_state *state, } EXPORT_SYMBOL(drm_dp_atomic_release_vcpi_slots);
+/* + * drm_dp_mst_update_first_link_slot_info() + * update the first link's total available slots and starting slot + * @mgr: manager to store the slot info. + * @encoding_format: detected link encoding format + */ +void drm_dp_mst_update_first_link_slot_info( + struct drm_dp_mst_topology_mgr *mgr, uint8_t encoding_format) +{ + if (encoding_format == DP_CAP_ANSI_128B132B) { + mgr->first_link_total_avail_slots = 64; + mgr->first_link_start_slot = 0; + } + DRM_DEBUG_KMS("%s encoding format on 0x%p -> total %d slots, start at slot %d\n", + (encoding_format == DP_CAP_ANSI_128B132B) ? "128b/132b":"8b/10b", + mgr, mgr->first_link_total_avail_slots, mgr->first_link_start_slot); +} +EXPORT_SYMBOL(drm_dp_mst_update_first_link_slot_info); + /** * drm_dp_mst_allocate_vcpi() - Allocate a virtual channel * @mgr: manager for this port @@ -4518,8 +4546,8 @@ bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
ret = drm_dp_init_vcpi(mgr, &port->vcpi, pbn, slots); if (ret) { - DRM_DEBUG_KMS("failed to init vcpi slots=%d max=63 ret=%d\n", - DIV_ROUND_UP(pbn, mgr->pbn_div), ret); + DRM_DEBUG_KMS("failed to init vcpi slots=%d max=%d ret=%d\n", + DIV_ROUND_UP(pbn, mgr->pbn_div), mgr->first_link_total_avail_slots, ret); drm_dp_mst_topology_put_port(port); goto out; } @@ -5162,7 +5190,7 @@ drm_dp_mst_atomic_check_vcpi_alloc_limit(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_topology_state *mst_state) { struct drm_dp_vcpi_allocation *vcpi; - int avail_slots = 63, payload_count = 0; + int avail_slots = mgr->first_link_total_avail_slots, payload_count = 0;
list_for_each_entry(vcpi, &mst_state->vcpis, next) { /* Releasing VCPI is always OK-even if the port is gone */ @@ -5191,7 +5219,7 @@ drm_dp_mst_atomic_check_vcpi_alloc_limit(struct drm_dp_mst_topology_mgr *mgr, } DRM_DEBUG_ATOMIC("[MST MGR:%p] mst state %p VCPI avail=%d used=%d\n", mgr, mst_state, avail_slots, - 63 - avail_slots); + mgr->first_link_total_avail_slots - avail_slots);
return 0; } @@ -5455,6 +5483,8 @@ int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr, if (!mgr->proposed_vcpis) return -ENOMEM; set_bit(0, &mgr->payload_mask); + mgr->first_link_total_avail_slots = 63; + mgr->first_link_start_slot = 1;
mst_state = kzalloc(sizeof(*mst_state), GFP_KERNEL); if (mst_state == NULL) diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h index bd1c39907b92..f4310b3705e7 100644 --- a/include/drm/drm_dp_mst_helper.h +++ b/include/drm/drm_dp_mst_helper.h @@ -653,6 +653,13 @@ struct drm_dp_mst_topology_mgr { */ int pbn_div;
+ /** + * @first_link_total_avail_slots: frist link total slots available. + * @first_link_start_slot: start slot index for real data transmission. + */ + u8 first_link_total_avail_slots; + u8 first_link_start_slot; + /** * @funcs: Atomic helper callbacks */ @@ -795,6 +802,7 @@ int drm_dp_mst_get_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp
void drm_dp_mst_reset_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port);
+void drm_dp_mst_update_first_link_slot_info(struct drm_dp_mst_topology_mgr *mgr, uint8_t encoding_format);
void drm_dp_mst_deallocate_vcpi(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port);