[PATCH] drm/i915/display: Assert valid cpu_transcoder

[Jonathan Cavitt <jonathan.cavitt@intel.com>]

Static analysis issue:

Bit operations are being performed using bit offsets computed from
cpu_transcoder values, which may (albeit unlikely) be -1.  Assert this
is not the case when relevant.

Signed-off-by: Jonathan Cavitt <jonathan.cavitt@intel.com>
---
 drivers/gpu/drm/i915/display/intel_ddi.c     | 8 +++++++-
 drivers/gpu/drm/i915/display/intel_display.c | 5 +++++
 drivers/gpu/drm/i915/display/intel_dp.c      | 3 +++
 drivers/gpu/drm/i915/display/intel_dp_mst.c  | 3 +++
 4 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
index d8739e2bb004..ec947c415e5f 100644
--- a/drivers/gpu/drm/i915/display/intel_ddi.c
+++ b/drivers/gpu/drm/i915/display/intel_ddi.c
@@ -3876,7 +3876,8 @@ static void intel_ddi_set_idle_link_train(struct intel_dp *intel_dp,
 static bool intel_ddi_is_audio_enabled(struct intel_display *display,
 				       enum transcoder cpu_transcoder)
 {
-	if (cpu_transcoder == TRANSCODER_EDP)
+	if (cpu_transcoder == TRANSCODER_EDP ||
+	    drm_WARN_ON(display->drm, cpu_transcoder == INVALID_TRANSCODER))
 		return false;
 
 	if (!intel_display_power_is_enabled(display, POWER_DOMAIN_AUDIO_MMIO))
@@ -4611,6 +4612,8 @@ intel_ddi_port_sync_transcoders(const struct intel_crtc_state *ref_crtc_state,
 		if (!crtcs_port_sync_compatible(ref_crtc_state,
 						crtc_state))
 			continue;
+		if (drm_WARN_ON(display->drm, crtc_state->cpu_transcoder == INVALID_TRANSCODER))
+			continue;
 		transcoders |= BIT(crtc_state->cpu_transcoder);
 	}
 
@@ -4649,6 +4652,9 @@ static int intel_ddi_compute_config_late(struct intel_encoder *encoder,
 	else
 		crtc_state->master_transcoder = ffs(port_sync_transcoders) - 1;
 
+	if (drm_WARN_ON(display->drm, crtc_state->cpu_transcoder == INVALID_TRANSCODER))
+		return -EINVAL;
+
 	if (crtc_state->master_transcoder == crtc_state->cpu_transcoder) {
 		crtc_state->master_transcoder = INVALID_TRANSCODER;
 		crtc_state->sync_mode_slaves_mask =
diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index 7491e00e3858..c9d50240d813 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -5855,9 +5855,14 @@ static bool intel_cpu_transcoders_need_modeset(struct intel_atomic_state *state,
 {
 	const struct intel_crtc_state *new_crtc_state;
 	struct intel_crtc *crtc;
+	struct drm_device *drm;
 	int i;
 
+	drm = to_intel_display(state)->drm;
+
 	for_each_new_intel_crtc_in_state(state, crtc, new_crtc_state, i) {
+		if (drm_WARN_ON(drm, new_crtc_state->cpu_transcoder == INVALID_TRANSCODER))
+			continue;
 		if (new_crtc_state->hw.enable &&
 		    transcoders & BIT(new_crtc_state->cpu_transcoder) &&
 		    intel_crtc_needs_modeset(new_crtc_state))
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 79fd3b8d8b25..402b22423ff2 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -6412,6 +6412,9 @@ static int intel_modeset_affected_transcoders(struct intel_atomic_state *state,
 		if (!crtc_state->hw.enable)
 			continue;
 
+		if (drm_WARN_ON(display->drm, crtc_state->cpu_transcoder == INVALID_TRANSCODER))
+			continue;
+
 		if (!(transcoders & BIT(crtc_state->cpu_transcoder)))
 			continue;
 
diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
index 24f8e60df9ac..f6690130d1cb 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
@@ -741,6 +741,9 @@ intel_dp_mst_transcoder_mask(struct intel_atomic_state *state,
 		if (!crtc_state->hw.active)
 			continue;
 
+		if (drm_WARN_ON(display->drm, crtc_state->cpu_transcoder == INVALID_TRANSCODER))
+			continue;
+
 		transcoders |= BIT(crtc_state->cpu_transcoder);
 	}
 
-- 
2.43.0