[PATCH v2 1/1] drm/dp_mst: Use kHz as link rate units when settig source max link caps at init

Nikola Cornij
2021-05-12T22:07:35Z

[why]
Link rate in kHz is what is eventually required to calculate the link
bandwidth, which makes kHz a more generic unit. This should also make
forward-compatibility with new DP standards easier.

[how]
- Replace 'link rate DPCD code' with 'link rate in kHz' when used with
drm_dp_mst_topology_mgr_init()
- Add/remove related DPCD code conversion from/to kHz where applicable

Signed-off-by: Nikola Cornij <nikola.cornij@amd.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
---
.../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c | 4 ++--
drivers/gpu/drm/drm_dp_mst_topology.c | 8 ++++----
drivers/gpu/drm/i915/display/intel_dp_mst.c | 4 ++--
drivers/gpu/drm/nouveau/dispnv50/disp.c | 5 +++--
drivers/gpu/drm/radeon/radeon_dp_mst.c | 2 +-
include/drm/drm_dp_mst_helper.h | 8 ++++----
6 files changed, 16 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
index 4a0c24ce5f7d..f78dd021f591 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
@@ -458,8 +458,8 @@ void amdgpu_dm_initialize_dp_connector(struct amdgpu_display_manager *dm,
&aconnector->dm_dp_aux.aux,
16,
4,
- (u8)max_link_enc_cap.lane_count,
- (u8)max_link_enc_cap.link_rate,
+ max_link_enc_cap.lane_count,
+ drm_dp_bw_code_to_link_rate(max_link_enc_cap.link_rate),
aconnector->connector_id);

drm_connector_attach_dp_subconnector_property(&aconnector->base);
diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index 54604633e65c..32b7f8983b94 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -3722,9 +3722,9 @@ int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool ms
}

lane_count = min_t(int, mgr->dpcd[2] & DP_MAX_LANE_COUNT_MASK, mgr->max_lane_count);
- link_rate = min_t(int, mgr->dpcd[1], mgr->max_link_rate);
+ link_rate = min_t(int, drm_dp_bw_code_to_link_rate(mgr->dpcd[1]), mgr->max_link_rate);
mgr->pbn_div = drm_dp_get_vc_payload_bw(mgr,
- drm_dp_bw_code_to_link_rate(link_rate),
+ link_rate,
lane_count);
if (mgr->pbn_div == 0) {
ret = -EINVAL;
@@ -5454,7 +5454,7 @@ EXPORT_SYMBOL(drm_atomic_get_mst_topology_state);
* @max_dpcd_transaction_bytes: hw specific DPCD transaction limit
* @max_payloads: maximum number of payloads this GPU can source
* @max_lane_count: maximum number of lanes this GPU supports
- * @max_link_rate: maximum link rate this GPU supports, units as in DPCD
+ * @max_link_rate: maximum link rate per lane this GPU supports in kHz
* @conn_base_id: the connector object ID the MST device is connected to.
*
* Return 0 for success, or negative error code on failure
@@ -5462,7 +5462,7 @@ EXPORT_SYMBOL(drm_atomic_get_mst_topology_state);
int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr,
struct drm_device *dev, struct drm_dp_aux *aux,
int max_dpcd_transaction_bytes, int max_payloads,
- u8 max_lane_count, u8 max_link_rate,
+ int max_lane_count, int max_link_rate,
int conn_base_id)
{
struct drm_dp_mst_topology_state *mst_state;
diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
index f608c0cb98f4..26f65445bc8a 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
@@ -960,8 +960,8 @@ intel_dp_mst_encoder_init(struct intel_digital_port *dig_port, int conn_base_id)
intel_dp_create_fake_mst_encoders(dig_port);
ret = drm_dp_mst_topology_mgr_init(&intel_dp->mst_mgr, &i915->drm,
&intel_dp->aux, 16, 3,
- (u8)dig_port->max_lanes,
- drm_dp_link_rate_to_bw_code(max_source_rate),
+ dig_port->max_lanes,
+ max_source_rate,
conn_base_id);
if (ret)
return ret;
diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c
index c46d0374b6e6..f949767698fc 100644
--- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
+++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
@@ -1617,8 +1617,9 @@ nv50_mstm_new(struct nouveau_encoder *outp, struct drm_dp_aux *aux, int aux_max,
mstm->mgr.cbs = &nv50_mstm;

ret = drm_dp_mst_topology_mgr_init(&mstm->mgr, dev, aux, aux_max,
- (u8)max_payloads, outp->dcb->dpconf.link_nr,
- (u8)outp->dcb->dpconf.link_bw, conn_base_id);
+ max_payloads, outp->dcb->dpconf.link_nr,
+ drm_dp_bw_code_to_link_rate(outp->dcb->dpconf.link_bw),
+ conn_base_id);
if (ret)
return ret;

diff --git a/drivers/gpu/drm/radeon/radeon_dp_mst.c b/drivers/gpu/drm/radeon/radeon_dp_mst.c
index 13072c2a6502..ec867fa880a4 100644
--- a/drivers/gpu/drm/radeon/radeon_dp_mst.c
+++ b/drivers/gpu/drm/radeon/radeon_dp_mst.c
@@ -642,7 +642,7 @@ radeon_dp_mst_init(struct radeon_connector *radeon_connector)
radeon_connector->mst_mgr.cbs = &mst_cbs;
return drm_dp_mst_topology_mgr_init(&radeon_connector->mst_mgr, dev,
&radeon_connector->ddc_bus->aux, 16, 6,
- 4, (u8)max_link_rate,
+ 4, drm_dp_bw_code_to_link_rate(max_link_rate),
radeon_connector->base.base.id);
}

diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h
index c87a829b6498..ddb9231d0309 100644
--- a/include/drm/drm_dp_mst_helper.h
+++ b/include/drm/drm_dp_mst_helper.h
@@ -596,11 +596,11 @@ struct drm_dp_mst_topology_mgr {
/**
* @max_lane_count: maximum number of lanes the GPU can drive.
*/
- u8 max_lane_count;
+ int max_lane_count;
/**
- * @max_link_rate: maximum link rate per lane GPU can output.
+ * @max_link_rate: maximum link rate per lane GPU can output, in kHz.
*/
- u8 max_link_rate;
+ int max_link_rate;
/**
* @conn_base_id: DRM connector ID this mgr is connected to. Only used
* to build the MST connector path value.
@@ -774,7 +774,7 @@ int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr,
struct drm_device *dev, struct drm_dp_aux *aux,
int max_dpcd_transaction_bytes,
int max_payloads,
- u8 max_lane_count, u8 max_link_rate,
+ int max_lane_count, int max_link_rate,
int conn_base_id);

void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr);
--
2.25.1