// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2017 The Linux Foundation. All rights reserved.
 */

#include "mdp5_kms.h"

/*
 * As of now, there are only 2 combinations possible for source split:
 *
 * Left | Right
 * -----|------
 *  LM0 | LM1
 *  LM2 | LM5
 *
 */
static int lm_right_pair[] = { 1, -1, 5, -1, -1, -1 };

static int get_right_pair_idx(struct mdp5_kms *mdp5_kms, int lm)
{
        int i;
        int pair_lm;

        pair_lm = lm_right_pair[lm];
        if (pair_lm < 0)
                return -EINVAL;

        for (i = 0; i < mdp5_kms->num_hwmixers; i++) {
                struct mdp5_hw_mixer *mixer = mdp5_kms->hwmixers[i];

                if (mixer->lm == pair_lm)
                        return mixer->idx;
        }

        return -1;
}

int mdp5_mixer_assign(struct drm_atomic_state *s, struct drm_crtc *crtc,
                      uint32_t caps, struct mdp5_hw_mixer **mixer,
                      struct mdp5_hw_mixer **r_mixer)
{
        struct msm_drm_private *priv = s->dev->dev_private;
        struct mdp5_kms *mdp5_kms = to_mdp5_kms(to_mdp_kms(priv->kms));
        struct mdp5_global_state *global_state = mdp5_get_global_state(s);
        struct mdp5_hw_mixer_state *new_state;
        int i;

        if (IS_ERR(global_state))
                return PTR_ERR(global_state);

        new_state = &global_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 by a different CRTC. If there is a
                 * mixer already assigned to this CRTC, it means this call is
                 * a request to get an additional right mixer. Assume that the
                 * existing mixer is the 'left' one, and try to see if we can
                 * get its corresponding 'right' pair.
                 */
                if (new_state->hwmixer_to_crtc[cur->idx] &&
                    new_state->hwmixer_to_crtc[cur->idx] != crtc)
                        continue;

                /* skip if doesn't support some required caps: */
                if (caps & ~cur->caps)
                        continue;

                if (r_mixer) {
                        int pair_idx;

                        pair_idx = get_right_pair_idx(mdp5_kms, cur->lm);
                        if (pair_idx < 0)
                                return -EINVAL;

                        if (new_state->hwmixer_to_crtc[pair_idx])
                                continue;

                        *r_mixer = mdp5_kms->hwmixers[pair_idx];
                }

                /*
                 * prefer a pair-able LM over an unpairable one. We can
                 * switch the CRTC from Normal mode to Source Split mode
                 * without requiring a full modeset if we had already
                 * assigned this CRTC a pair-able LM.
                 *
                 * TODO: There will be assignment sequences which would
                 * result in the CRTC requiring a full modeset, even
                 * if we have the LM resources to prevent it. For a platform
                 * with a few displays, we don't run out of pair-able LMs
                 * so easily. For now, ignore the possibility of requiring
                 * a full modeset.
                 */
                if (!(*mixer) || cur->caps & MDP_LM_CAP_PAIR)
                        *mixer = cur;
        }

        if (!(*mixer))
                return -ENOMEM;

        if (r_mixer && !(*r_mixer))
                return -ENOMEM;

        DBG("assigning Layer Mixer %d to crtc %s", (*mixer)->lm, crtc->name);

        new_state->hwmixer_to_crtc[(*mixer)->idx] = crtc;
        if (r_mixer) {
                DBG("assigning Right Layer Mixer %d to crtc %s", (*r_mixer)->lm,
                    crtc->name);
                new_state->hwmixer_to_crtc[(*r_mixer)->idx] = crtc;
        }

        return 0;
}

int mdp5_mixer_release(struct drm_atomic_state *s, struct mdp5_hw_mixer *mixer)
{
        struct mdp5_global_state *global_state = mdp5_get_global_state(s);
        struct mdp5_hw_mixer_state *new_state;

        if (!mixer)
                return 0;

        if (IS_ERR(global_state))
                return PTR_ERR(global_state);

        new_state = &global_state->hwmixer;

        if (WARN_ON(!new_state->hwmixer_to_crtc[mixer->idx]))
                return -EINVAL;

        DBG("%s: release from crtc %s", mixer->name,
            new_state->hwmixer_to_crtc[mixer->idx]->name);

        new_state->hwmixer_to_crtc[mixer->idx] = NULL;

        return 0;
}

static const char * const mixer_names[] = {
        "LM0", "LM1", "LM2", "LM3", "LM4", "LM5",
};

struct mdp5_hw_mixer *mdp5_mixer_init(struct drm_device *dev,
                                      const struct mdp5_lm_instance *lm)
{
        struct mdp5_hw_mixer *mixer;

        mixer = devm_kzalloc(dev->dev, sizeof(*mixer), GFP_KERNEL);
        if (!mixer)
                return ERR_PTR(-ENOMEM);

        mixer->name = mixer_names[lm->id];
        mixer->lm = lm->id;
        mixer->caps = lm->caps;
        mixer->pp = lm->pp;
        mixer->dspp = lm->dspp;
        mixer->flush_mask = mdp_ctl_flush_mask_lm(lm->id);

        return mixer;
}