// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2014 Red Hat
 * Author: Rob Clark <robdclark@gmail.com>
 */

#include <drm/drm_atomic_uapi.h>
#include <drm/drm_gem_atomic_helper.h>
#include <drm/drm_vblank.h>

#include "msm_atomic_trace.h"
#include "msm_drv.h"
#include "msm_gem.h"
#include "msm_kms.h"

int msm_atomic_prepare_fb(struct drm_plane *plane,
                          struct drm_plane_state *new_state)
{
        struct msm_drm_private *priv = plane->dev->dev_private;
        struct msm_kms *kms = priv->kms;

        if (!new_state->fb)
                return 0;

        drm_gem_plane_helper_prepare_fb(plane, new_state);

        return msm_framebuffer_prepare(new_state->fb, kms->aspace);
}

/*
 * Helpers to control vblanks while we flush.. basically just to ensure
 * that vblank accounting is switched on, so we get valid seqn/timestamp
 * on pageflip events (if requested)
 */

static void vblank_get(struct msm_kms *kms, unsigned crtc_mask)
{
        struct drm_crtc *crtc;

        for_each_crtc_mask(kms->dev, crtc, crtc_mask) {
                if (!crtc->state->active)
                        continue;
                drm_crtc_vblank_get(crtc);
        }
}

static void vblank_put(struct msm_kms *kms, unsigned crtc_mask)
{
        struct drm_crtc *crtc;

        for_each_crtc_mask(kms->dev, crtc, crtc_mask) {
                if (!crtc->state->active)
                        continue;
                drm_crtc_vblank_put(crtc);
        }
}

static void lock_crtcs(struct msm_kms *kms, unsigned int crtc_mask)
{
        int crtc_index;
        struct drm_crtc *crtc;

        for_each_crtc_mask(kms->dev, crtc, crtc_mask) {
                crtc_index = drm_crtc_index(crtc);
                mutex_lock_nested(&kms->commit_lock[crtc_index], crtc_index);
        }
}

static void unlock_crtcs(struct msm_kms *kms, unsigned int crtc_mask)
{
        struct drm_crtc *crtc;

        for_each_crtc_mask_reverse(kms->dev, crtc, crtc_mask)
                mutex_unlock(&kms->commit_lock[drm_crtc_index(crtc)]);
}

static void msm_atomic_async_commit(struct msm_kms *kms, int crtc_idx)
{
        unsigned crtc_mask = BIT(crtc_idx);

        trace_msm_atomic_async_commit_start(crtc_mask);

        lock_crtcs(kms, crtc_mask);

        if (!(kms->pending_crtc_mask & crtc_mask)) {
                unlock_crtcs(kms, crtc_mask);
                goto out;
        }

        kms->pending_crtc_mask &= ~crtc_mask;

        kms->funcs->enable_commit(kms);

        vblank_get(kms, crtc_mask);

        /*
         * Flush hardware updates:
         */
        trace_msm_atomic_flush_commit(crtc_mask);
        kms->funcs->flush_commit(kms, crtc_mask);

        /*
         * Wait for flush to complete:
         */
        trace_msm_atomic_wait_flush_start(crtc_mask);
        kms->funcs->wait_flush(kms, crtc_mask);
        trace_msm_atomic_wait_flush_finish(crtc_mask);

        vblank_put(kms, crtc_mask);

        kms->funcs->complete_commit(kms, crtc_mask);
        unlock_crtcs(kms, crtc_mask);
        kms->funcs->disable_commit(kms);

out:
        trace_msm_atomic_async_commit_finish(crtc_mask);
}

static enum hrtimer_restart msm_atomic_pending_timer(struct hrtimer *t)
{
        struct msm_pending_timer *timer = container_of(t,
                        struct msm_pending_timer, timer);

        kthread_queue_work(timer->worker, &timer->work);

        return HRTIMER_NORESTART;
}

static void msm_atomic_pending_work(struct kthread_work *work)
{
        struct msm_pending_timer *timer = container_of(work,
                        struct msm_pending_timer, work);

        msm_atomic_async_commit(timer->kms, timer->crtc_idx);
}

int msm_atomic_init_pending_timer(struct msm_pending_timer *timer,
                struct msm_kms *kms, int crtc_idx)
{
        timer->kms = kms;
        timer->crtc_idx = crtc_idx;
        hrtimer_init(&timer->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
        timer->timer.function = msm_atomic_pending_timer;

        timer->worker = kthread_create_worker(0, "atomic-worker-%d", crtc_idx);
        if (IS_ERR(timer->worker)) {
                int ret = PTR_ERR(timer->worker);
                timer->worker = NULL;
                return ret;
        }
        sched_set_fifo(timer->worker->task);
        kthread_init_work(&timer->work, msm_atomic_pending_work);

        return 0;
}

void msm_atomic_destroy_pending_timer(struct msm_pending_timer *timer)
{
        if (timer->worker)
                kthread_destroy_worker(timer->worker);
}

static bool can_do_async(struct drm_atomic_state *state,
                struct drm_crtc **async_crtc)
{
        struct drm_connector_state *connector_state;
        struct drm_connector *connector;
        struct drm_crtc_state *crtc_state;
        struct drm_crtc *crtc;
        int i, num_crtcs = 0;

        if (!(state->legacy_cursor_update || state->async_update))
                return false;

        /* any connector change, means slow path: */
        for_each_new_connector_in_state(state, connector, connector_state, i)
                return false;

        for_each_new_crtc_in_state(state, crtc, crtc_state, i) {
                if (drm_atomic_crtc_needs_modeset(crtc_state))
                        return false;
                if (++num_crtcs > 1)
                        return false;
                *async_crtc = crtc;
        }

        return true;
}

/* Get bitmask of crtcs that will need to be flushed.  The bitmask
 * can be used with for_each_crtc_mask() iterator, to iterate
 * effected crtcs without needing to preserve the atomic state.
 */
static unsigned get_crtc_mask(struct drm_atomic_state *state)
{
        struct drm_crtc_state *crtc_state;
        struct drm_crtc *crtc;
        unsigned i, mask = 0;

        for_each_new_crtc_in_state(state, crtc, crtc_state, i)
                mask |= drm_crtc_mask(crtc);

        return mask;
}

void msm_atomic_commit_tail(struct drm_atomic_state *state)
{
        struct drm_device *dev = state->dev;
        struct msm_drm_private *priv = dev->dev_private;
        struct msm_kms *kms = priv->kms;
        struct drm_crtc *async_crtc = NULL;
        unsigned crtc_mask = get_crtc_mask(state);
        bool async = kms->funcs->vsync_time &&
                        can_do_async(state, &async_crtc);

        trace_msm_atomic_commit_tail_start(async, crtc_mask);

        kms->funcs->enable_commit(kms);

        /*
         * Ensure any previous (potentially async) commit has
         * completed:
         */
        lock_crtcs(kms, crtc_mask);
        trace_msm_atomic_wait_flush_start(crtc_mask);
        kms->funcs->wait_flush(kms, crtc_mask);
        trace_msm_atomic_wait_flush_finish(crtc_mask);

        /*
         * Now that there is no in-progress flush, prepare the
         * current update:
         */
        kms->funcs->prepare_commit(kms, state);

        /*
         * Push atomic updates down to hardware:
         */
        drm_atomic_helper_commit_modeset_disables(dev, state);
        drm_atomic_helper_commit_planes(dev, state, 0);
        drm_atomic_helper_commit_modeset_enables(dev, state);

        if (async) {
                struct msm_pending_timer *timer =
                        &kms->pending_timers[drm_crtc_index(async_crtc)];

                /* async updates are limited to single-crtc updates: */
                WARN_ON(crtc_mask != drm_crtc_mask(async_crtc));

                /*
                 * Start timer if we don't already have an update pending
                 * on this crtc:
                 */
                if (!(kms->pending_crtc_mask & crtc_mask)) {
                        ktime_t vsync_time, wakeup_time;

                        kms->pending_crtc_mask |= crtc_mask;

                        vsync_time = kms->funcs->vsync_time(kms, async_crtc);
                        wakeup_time = ktime_sub(vsync_time, ms_to_ktime(1));

                        hrtimer_start(&timer->timer, wakeup_time,
                                        HRTIMER_MODE_ABS);
                }

                kms->funcs->disable_commit(kms);
                unlock_crtcs(kms, crtc_mask);
                /*
                 * At this point, from drm core's perspective, we
                 * are done with the atomic update, so we can just
                 * go ahead and signal that it is done:
                 */
                drm_atomic_helper_commit_hw_done(state);
                drm_atomic_helper_cleanup_planes(dev, state);

                trace_msm_atomic_commit_tail_finish(async, crtc_mask);

                return;
        }

        /*
         * If there is any async flush pending on updated crtcs, fold
         * them into the current flush.
         */
        kms->pending_crtc_mask &= ~crtc_mask;

        vblank_get(kms, crtc_mask);

        /*
         * Flush hardware updates:
         */
        trace_msm_atomic_flush_commit(crtc_mask);
        kms->funcs->flush_commit(kms, crtc_mask);
        unlock_crtcs(kms, crtc_mask);
        /*
         * Wait for flush to complete:
         */
        trace_msm_atomic_wait_flush_start(crtc_mask);
        kms->funcs->wait_flush(kms, crtc_mask);
        trace_msm_atomic_wait_flush_finish(crtc_mask);

        vblank_put(kms, crtc_mask);

        lock_crtcs(kms, crtc_mask);
        kms->funcs->complete_commit(kms, crtc_mask);
        unlock_crtcs(kms, crtc_mask);
        kms->funcs->disable_commit(kms);

        drm_atomic_helper_commit_hw_done(state);
        drm_atomic_helper_cleanup_planes(dev, state);

        trace_msm_atomic_commit_tail_finish(async, crtc_mask);
}