drm/i915/dp: Extract drm_dp_read_mst_cap()

Just a tiny drive-by cleanup, we can consolidate i915's code for
checking for MST support into a helper to be shared across drivers.

v5:
* Drop !!()
* Move drm_dp_has_mst() out of header
* Change name from drm_dp_has_mst() to drm_dp_read_mst_cap()

Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Sean Paul <sean@poorly.run>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200826182456.322681-10-lyude@redhat.com

diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index b23cb2fec3f35f8b8eaa231b6a13267e7041cab7..61755c26fac03cce121221e13bad37c640b0221d 100644 (file)
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -3486,6 +3486,28 @@ static int drm_dp_get_vc_payload_bw(u8 dp_link_bw, u8  dp_link_count)
        return dp_link_bw * dp_link_count / 2;
 }
 
+/**
+ * drm_dp_read_mst_cap() - check whether or not a sink supports MST
+ * @aux: The DP AUX channel to use
+ * @dpcd: A cached copy of the DPCD capabilities for this sink
+ *
+ * Returns: %True if the sink supports MST, %false otherwise
+ */
+bool drm_dp_read_mst_cap(struct drm_dp_aux *aux,
+                        const u8 dpcd[DP_RECEIVER_CAP_SIZE])
+{
+       u8 mstm_cap;
+
+       if (dpcd[DP_DPCD_REV] < DP_DPCD_REV_12)
+               return false;
+
+       if (drm_dp_dpcd_readb(aux, DP_MSTM_CAP, &mstm_cap) != 1)
+               return false;
+
+       return mstm_cap & DP_MST_CAP;
+}
+EXPORT_SYMBOL(drm_dp_read_mst_cap);
+
 /**
  * drm_dp_mst_topology_mgr_set_mst() - Set the MST state for a topology manager
  * @mgr: manager to set state for

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 79c27f91f42c0a8f32bbbea38e9db77d27bfb895..4c7314b7a84e4d4cefebc1166706b8d84bd0aad7 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -4699,20 +4699,6 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp)
        return true;
 }
 
-static bool
-intel_dp_sink_can_mst(struct intel_dp *intel_dp)
-{
-       u8 mstm_cap;
-
-       if (intel_dp->dpcd[DP_DPCD_REV] < 0x12)
-               return false;
-
-       if (drm_dp_dpcd_readb(&intel_dp->aux, DP_MSTM_CAP, &mstm_cap) != 1)
-               return false;
-
-       return mstm_cap & DP_MST_CAP;
-}
-
 static bool
 intel_dp_can_mst(struct intel_dp *intel_dp)
 {
@@ -4720,7 +4706,7 @@ intel_dp_can_mst(struct intel_dp *intel_dp)
 
        return i915->params.enable_dp_mst &&
                intel_dp->can_mst &&
-               intel_dp_sink_can_mst(intel_dp);
+               drm_dp_read_mst_cap(&intel_dp->aux, intel_dp->dpcd);
 }
 
 static void
@@ -4729,7 +4715,7 @@ intel_dp_configure_mst(struct intel_dp *intel_dp)
        struct drm_i915_private *i915 = dp_to_i915(intel_dp);
        struct intel_encoder *encoder =
                &dp_to_dig_port(intel_dp)->base;
-       bool sink_can_mst = intel_dp_sink_can_mst(intel_dp);
+       bool sink_can_mst = drm_dp_read_mst_cap(&intel_dp->aux, intel_dp->dpcd);
 
        drm_dbg_kms(&i915->drm,
                    "[ENCODER:%d:%s] MST support: port: %s, sink: %s, modparam: %s\n",

diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h
index 8b9eb4db3381c45a112e039510fce5ceaf4e72f8..6ae5860d8644e29a83c23cced654223121aa2eb5 100644 (file)
--- a/include/drm/drm_dp_mst_helper.h
+++ b/include/drm/drm_dp_mst_helper.h
@@ -728,10 +728,9 @@ int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr,
 
 void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr);
 
-
+bool drm_dp_read_mst_cap(struct drm_dp_aux *aux, const u8 dpcd[DP_RECEIVER_CAP_SIZE]);
 int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool mst_state);
 
-
 int drm_dp_mst_hpd_irq(struct drm_dp_mst_topology_mgr *mgr, u8 *esi, bool *handled);