disp: msm: sde: revert to previous smmu state upon failure to switch

This change saves the previous state before moving into the transitional
smmu state, during secure-display/secure-camera usecases. Upon failure
to complete the transition, set smmu state to the previous state.
Previously, smmu state was staying in transitional state.

Change-Id: I1a78ddcf6ac1c7ea66c8c2095cd1a6d6160647a1
Signed-off-by: Samantha Tran <[email protected]>

msm/sde/sde_crtc.c

@@ -1781,6 +1781,8 @@ int sde_crtc_get_secure_transition_ops(struct drm_crtc *crtc,
 		return -EINVAL;
 
 	smmu_state = &sde_kms->smmu_state;
+	smmu_state->prev_state = smmu_state->state;
+
 	sde_crtc = to_sde_crtc(crtc);
 	secure_level = sde_crtc_get_secure_level(crtc, crtc->state);
 	catalog = sde_kms->catalog;

msm/sde/sde_kms.c

@@ -528,12 +528,24 @@ static int _sde_kms_secure_ctrl(struct sde_kms *sde_kms, struct drm_crtc *crtc,
 end:
 	smmu_state->sui_misr_state = NONE;
 	smmu_state->transition_type = NONE;
-	smmu_state->transition_error = ret ? true : false;
+	smmu_state->transition_error = false;
 
-	SDE_DEBUG("crtc %d: old_state %d, new_state %d, sec_lvl %d, ret %d\n",
-			DRMID(crtc), old_smmu_state, smmu_state->state,
-			smmu_state->secure_level, ret);
-	SDE_EVT32(DRMID(crtc), smmu_state->state, smmu_state->transition_type,
+	/*
+	 * If switch failed, toggling secure_level is enough since
+	 * there are only two secure levels - secure/non-secure
+	 */
+	if (ret) {
+		smmu_state->transition_error = true;
+		smmu_state->state = smmu_state->prev_state;
+		smmu_state->secure_level = !smmu_state->secure_level;
+	}
+
+	SDE_DEBUG(
+		"crtc %d: old_state %d, req_state %d, new_state %d, sec_lvl %d, ret %d\n",
+			DRMID(crtc), smmu_state->prev_state, old_smmu_state,
+			smmu_state->state, smmu_state->secure_level, ret);
+	SDE_EVT32(DRMID(crtc), smmu_state->prev_state,
+			smmu_state->state, smmu_state->transition_type,
 			smmu_state->transition_error, smmu_state->secure_level,
 			smmu_state->sui_misr_state, ret, SDE_EVTLOG_FUNC_EXIT);
 

msm/sde/sde_kms.h

@@ -187,12 +187,14 @@ enum frame_trigger_mode_type {
 /**
  * struct sde_kms_smmu_state_data: stores the smmu state and transition type
  * @state: current state of smmu context banks
+ * @prev_state: previous state of smmu context banks
  * @secure_level: secure level cached from crtc
  * @transition_type: transition request type
  * @transition_error: whether there is error while transitioning the state
  */
 struct sde_kms_smmu_state_data {
 	uint32_t state;
+	uint32_t prev_state;
 	uint32_t secure_level;
 	uint32_t transition_type;
 	uint32_t transition_error;