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@xxxxxxx>
---
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);
--
2.25.1
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