drm/msm/mdp5: Prepare for dynamic assignment of mixers

Add the stuff needed to allow dynamically assigning a mixer to a CRTC.

Since mixers are a resource that can be shared across multiple CRTCs, we
need to maintain a 'hwmixer_to_crtc' map in the global atomic state,
acquire the mdp5_kms.state_lock modeset lock and so on.

The mixer is assigned in the CRTC's atomic_check() func, a failure will
result in the new state being cleanly rolled back.

The mixer assignment itself is straightforward, and almost identical to
what we do for hwpipes. We don't need to grab the old hwmixer_to_crtc
state like we do in hwpipes since we don't need to compare anything
with the old state at the moment.

The only LM capability we care about at the moment is whether the mixer
instance can be used to display stuff (i.e, connect to an INTF
downstream).
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>

drivers/gpu/drm/msm/mdp/mdp5/mdp5_crtc.c

@@ -367,6 +367,30 @@ static void mdp5_crtc_enable(struct drm_crtc *crtc)
 	mdp5_crtc->enabled = true;
 }
 
+int mdp5_crtc_setup_pipeline(struct drm_crtc *crtc,
+			     struct drm_crtc_state *new_crtc_state)
+{
+	struct mdp5_crtc_state *mdp5_cstate =
+			to_mdp5_crtc_state(new_crtc_state);
+	struct mdp5_pipeline *pipeline = &mdp5_cstate->pipeline;
+	bool new_mixer = false;
+
+	new_mixer = !pipeline->mixer;
+
+	if (new_mixer) {
+		struct mdp5_hw_mixer *old_mixer = pipeline->mixer;
+
+		pipeline->mixer = mdp5_mixer_assign(new_crtc_state->state, crtc,
+						    MDP_LM_CAP_DISPLAY);
+		if (IS_ERR(pipeline->mixer))
+			return PTR_ERR(pipeline->mixer);
+
+		mdp5_mixer_release(new_crtc_state->state, old_mixer);
+	}
+
+	return 0;
+}
+
 struct plane_state {
 	struct drm_plane *plane;
 	struct mdp5_plane_state *state;
@@ -399,6 +423,7 @@ static int mdp5_crtc_atomic_check(struct drm_crtc *crtc,
 	const struct drm_plane_state *pstate;
 	bool cursor_plane = false;
 	int cnt = 0, base = 0, i;
+	int ret;
 
 	DBG("%s: check", crtc->name);
 
@@ -412,6 +437,12 @@ static int mdp5_crtc_atomic_check(struct drm_crtc *crtc,
 			cursor_plane = true;
 	}
 
+	ret = mdp5_crtc_setup_pipeline(crtc, state);
+	if (ret) {
+		dev_err(dev->dev, "couldn't assign mixers %d\n", ret);
+		return ret;
+	}
+
 	/* assign a stage based on sorted zpos property */
 	sort(pstates, cnt, sizeof(pstates[0]), pstate_cmp, NULL);
 

drivers/gpu/drm/msm/mdp/mdp5/mdp5_kms.c

@@ -93,6 +93,7 @@ struct mdp5_state *mdp5_get_state(struct drm_atomic_state *s)
 
 	/* Copy state: */
 	new_state->hwpipe = mdp5_kms->state->hwpipe;
+	new_state->hwmixer = mdp5_kms->state->hwmixer;
 	if (mdp5_kms->smp)
 		new_state->smp = mdp5_kms->state->smp;
 

drivers/gpu/drm/msm/mdp/mdp5/mdp5_kms.h

@@ -90,6 +90,7 @@ struct mdp5_kms {
  */
 struct mdp5_state {
 	struct mdp5_hw_pipe_state hwpipe;
+	struct mdp5_hw_mixer_state hwmixer;
 	struct mdp5_smp_state smp;
 };
 

drivers/gpu/drm/msm/mdp/mdp5/mdp5_mixer.c

@@ -16,6 +16,61 @@
 
 #include "mdp5_kms.h"
 
+struct mdp5_hw_mixer *mdp5_mixer_assign(struct drm_atomic_state *s,
+					struct drm_crtc *crtc, uint32_t caps)
+{
+	struct msm_drm_private *priv = s->dev->dev_private;
+	struct mdp5_kms *mdp5_kms = to_mdp5_kms(to_mdp_kms(priv->kms));
+	struct mdp5_state *state = mdp5_get_state(s);
+	struct mdp5_hw_mixer_state *new_state;
+	struct mdp5_hw_mixer *mixer = NULL;
+	int i;
+
+	if (IS_ERR(state))
+		return ERR_CAST(state);
+
+	new_state = &state->hwmixer;
+
+	for (i = 0; i < mdp5_kms->num_hwmixers; i++) {
+		struct mdp5_hw_mixer *cur = mdp5_kms->hwmixers[i];
+
+		/* skip if already in-use */
+		if (new_state->hwmixer_to_crtc[cur->idx])
+			continue;
+
+		/* skip if doesn't support some required caps: */
+		if (caps & ~cur->caps)
+			continue;
+
+		if (!mixer)
+			mixer = cur;
+	}
+
+	if (!mixer)
+		return ERR_PTR(-ENOMEM);
+
+	new_state->hwmixer_to_crtc[mixer->idx] = crtc;
+
+	return mixer;
+}
+
+void mdp5_mixer_release(struct drm_atomic_state *s, struct mdp5_hw_mixer *mixer)
+{
+	struct mdp5_state *state = mdp5_get_state(s);
+	struct mdp5_hw_mixer_state *new_state = &state->hwmixer;
+
+	if (!mixer)
+		return;
+
+	if (WARN_ON(!new_state->hwmixer_to_crtc[mixer->idx]))
+		return;
+
+	DBG("%s: release from crtc %s", mixer->name,
+	    new_state->hwmixer_to_crtc[mixer->idx]->name);
+
+	new_state->hwmixer_to_crtc[mixer->idx] = NULL;
+}
+
 void mdp5_mixer_destroy(struct mdp5_hw_mixer *mixer)
 {
 	kfree(mixer);

drivers/gpu/drm/msm/mdp/mdp5/mdp5_mixer.h

@@ -31,7 +31,16 @@ struct mdp5_hw_mixer {
 	uint32_t flush_mask;      /* used to commit LM registers */
 };
 
+/* global atomic state of assignment between CRTCs and Layer Mixers: */
+struct mdp5_hw_mixer_state {
+	struct drm_crtc *hwmixer_to_crtc[8];
+};
+
 struct mdp5_hw_mixer *mdp5_mixer_init(const struct mdp5_lm_instance *lm);
 void mdp5_mixer_destroy(struct mdp5_hw_mixer *lm);
+struct mdp5_hw_mixer *mdp5_mixer_assign(struct drm_atomic_state *s,
+					struct drm_crtc *crtc, uint32_t caps);
+void mdp5_mixer_release(struct drm_atomic_state *s,
+			struct mdp5_hw_mixer *mixer);
 
 #endif /* __MDP5_LM_H__ */