[RFC v4 09/20] drm/i915/dp: Extract drm_dp_has_mst()

Lyude Paul
2020-08-25T19:51:35Z

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.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Sean Paul <sean@poorly.run>
---
drivers/gpu/drm/i915/display/intel_dp.c | 18 ++----------------
include/drm/drm_dp_mst_helper.h | 22 ++++++++++++++++++++++
2 files changed, 24 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 79c27f91f42c0..1e29d3a012856 100644
--- 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_has_mst(&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_has_mst(&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 8b9eb4db3381c..2d8983a713e8c 100644
--- a/include/drm/drm_dp_mst_helper.h
+++ b/include/drm/drm_dp_mst_helper.h
@@ -911,4 +911,26 @@ __drm_dp_mst_state_iter_get(struct drm_atomic_state *state,
for ((__i) = 0; (__i) < (__state)->num_private_objs; (__i)++) \
for_each_if(__drm_dp_mst_state_iter_get((__state), &(mgr), NULL, &(new_state), (__i)))

+/**
+ * drm_dp_has_mst() - 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
+ */
+static inline bool
+drm_dp_has_mst(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);
+}
+
#endif
--
2.26.2