// SPDX-License-Identifier: MIT
/*
 * Copyright © 2016 Intel Corporation
 */

#include "gem/i915_gem_context.h"
#include "gt/intel_ring.h"

#include "i915_drv.h"
#include "intel_context.h"
#include "intel_engine_pm.h"

#include "mock_engine.h"
#include "selftests/mock_request.h"

static int mock_timeline_pin(struct intel_timeline *tl)
{
        int err;

        if (WARN_ON(!i915_gem_object_trylock(tl->hwsp_ggtt->obj, NULL)))
                return -EBUSY;

        err = intel_timeline_pin_map(tl);
        i915_gem_object_unlock(tl->hwsp_ggtt->obj);
        if (err)
                return err;

        atomic_inc(&tl->pin_count);
        return 0;
}

static void mock_timeline_unpin(struct intel_timeline *tl)
{
        GEM_BUG_ON(!atomic_read(&tl->pin_count));
        atomic_dec(&tl->pin_count);
}

static struct i915_vma *create_ring_vma(struct i915_ggtt *ggtt, int size)
{
        struct i915_address_space *vm = &ggtt->vm;
        struct drm_i915_private *i915 = vm->i915;
        struct drm_i915_gem_object *obj;
        struct i915_vma *vma;

        obj = i915_gem_object_create_internal(i915, size);
        if (IS_ERR(obj))
                return ERR_CAST(obj);

        vma = i915_vma_instance(obj, vm, NULL);
        if (IS_ERR(vma))
                goto err;

        return vma;

err:
        i915_gem_object_put(obj);
        return vma;
}

static struct intel_ring *mock_ring(struct intel_engine_cs *engine)
{
        const unsigned long sz = PAGE_SIZE;
        struct intel_ring *ring;

        ring = kzalloc(sizeof(*ring) + sz, GFP_KERNEL);
        if (!ring)
                return NULL;

        kref_init(&ring->ref);
        ring->size = sz;
        ring->effective_size = sz;
        ring->vaddr = (void *)(ring + 1);
        atomic_set(&ring->pin_count, 1);

        ring->vma = create_ring_vma(engine->gt->ggtt, PAGE_SIZE);
        if (IS_ERR(ring->vma)) {
                kfree(ring);
                return NULL;
        }

        intel_ring_update_space(ring);

        return ring;
}

static void mock_ring_free(struct intel_ring *ring)
{
        i915_vma_put(ring->vma);

        kfree(ring);
}

static struct i915_request *first_request(struct mock_engine *engine)
{
        return list_first_entry_or_null(&engine->hw_queue,
                                        struct i915_request,
                                        mock.link);
}

static void advance(struct i915_request *request)
{
        list_del_init(&request->mock.link);
        i915_request_mark_complete(request);
        GEM_BUG_ON(!i915_request_completed(request));

        intel_engine_signal_breadcrumbs(request->engine);
}

static void hw_delay_complete(struct timer_list *t)
{
        struct mock_engine *engine = timer_container_of(engine, t, hw_delay);
        struct i915_request *request;
        unsigned long flags;

        spin_lock_irqsave(&engine->hw_lock, flags);

        /* Timer fired, first request is complete */
        request = first_request(engine);
        if (request)
                advance(request);

        /*
         * Also immediately signal any subsequent 0-delay requests, but
         * requeue the timer for the next delayed request.
         */
        while ((request = first_request(engine))) {
                if (request->mock.delay) {
                        mod_timer(&engine->hw_delay,
                                  jiffies + request->mock.delay);
                        break;
                }

                advance(request);
        }

        spin_unlock_irqrestore(&engine->hw_lock, flags);
}

static void mock_context_unpin(struct intel_context *ce)
{
}

static void mock_context_post_unpin(struct intel_context *ce)
{
        i915_vma_unpin(ce->ring->vma);
}

static void mock_context_destroy(struct kref *ref)
{
        struct intel_context *ce = container_of(ref, typeof(*ce), ref);

        GEM_BUG_ON(intel_context_is_pinned(ce));

        if (test_bit(CONTEXT_ALLOC_BIT, &ce->flags)) {
                mock_ring_free(ce->ring);
                mock_timeline_unpin(ce->timeline);
        }

        intel_context_fini(ce);
        intel_context_free(ce);
}

static int mock_context_alloc(struct intel_context *ce)
{
        int err;

        ce->ring = mock_ring(ce->engine);
        if (!ce->ring)
                return -ENOMEM;

        ce->timeline = intel_timeline_create(ce->engine->gt);
        if (IS_ERR(ce->timeline)) {
                kfree(ce->engine);
                return PTR_ERR(ce->timeline);
        }

        err = mock_timeline_pin(ce->timeline);
        if (err) {
                intel_timeline_put(ce->timeline);
                ce->timeline = NULL;
                return err;
        }

        return 0;
}

static int mock_context_pre_pin(struct intel_context *ce,
                                struct i915_gem_ww_ctx *ww, void **unused)
{
        return i915_vma_pin_ww(ce->ring->vma, ww, 0, 0, PIN_GLOBAL | PIN_HIGH);
}

static int mock_context_pin(struct intel_context *ce, void *unused)
{
        return 0;
}

static void mock_context_reset(struct intel_context *ce)
{
}

static const struct intel_context_ops mock_context_ops = {
        .alloc = mock_context_alloc,

        .pre_pin = mock_context_pre_pin,
        .pin = mock_context_pin,
        .unpin = mock_context_unpin,
        .post_unpin = mock_context_post_unpin,

        .enter = intel_context_enter_engine,
        .exit = intel_context_exit_engine,

        .reset = mock_context_reset,
        .destroy = mock_context_destroy,
};

static int mock_request_alloc(struct i915_request *request)
{
        INIT_LIST_HEAD(&request->mock.link);
        request->mock.delay = 0;

        return 0;
}

static int mock_emit_flush(struct i915_request *request,
                           unsigned int flags)
{
        return 0;
}

static u32 *mock_emit_breadcrumb(struct i915_request *request, u32 *cs)
{
        return cs;
}

static void mock_submit_request(struct i915_request *request)
{
        struct mock_engine *engine =
                container_of(request->engine, typeof(*engine), base);
        unsigned long flags;

        i915_request_submit(request);

        spin_lock_irqsave(&engine->hw_lock, flags);
        list_add_tail(&request->mock.link, &engine->hw_queue);
        if (list_is_first(&request->mock.link, &engine->hw_queue)) {
                if (request->mock.delay)
                        mod_timer(&engine->hw_delay,
                                  jiffies + request->mock.delay);
                else
                        advance(request);
        }
        spin_unlock_irqrestore(&engine->hw_lock, flags);
}

static void mock_add_to_engine(struct i915_request *rq)
{
        lockdep_assert_held(&rq->engine->sched_engine->lock);
        list_move_tail(&rq->sched.link, &rq->engine->sched_engine->requests);
}

static void mock_remove_from_engine(struct i915_request *rq)
{
        struct intel_engine_cs *engine, *locked;

        /*
         * Virtual engines complicate acquiring the engine timeline lock,
         * as their rq->engine pointer is not stable until under that
         * engine lock. The simple ploy we use is to take the lock then
         * check that the rq still belongs to the newly locked engine.
         */

        locked = READ_ONCE(rq->engine);
        spin_lock_irq(&locked->sched_engine->lock);
        while (unlikely(locked != (engine = READ_ONCE(rq->engine)))) {
                spin_unlock(&locked->sched_engine->lock);
                spin_lock(&engine->sched_engine->lock);
                locked = engine;
        }
        list_del_init(&rq->sched.link);
        spin_unlock_irq(&locked->sched_engine->lock);
}

static void mock_reset_prepare(struct intel_engine_cs *engine)
{
}

static void mock_reset_rewind(struct intel_engine_cs *engine, bool stalled)
{
        GEM_BUG_ON(stalled);
}

static void mock_reset_cancel(struct intel_engine_cs *engine)
{
        struct mock_engine *mock =
                container_of(engine, typeof(*mock), base);
        struct i915_request *rq;
        unsigned long flags;

        timer_delete_sync(&mock->hw_delay);

        spin_lock_irqsave(&engine->sched_engine->lock, flags);

        /* Mark all submitted requests as skipped. */
        list_for_each_entry(rq, &engine->sched_engine->requests, sched.link)
                i915_request_put(i915_request_mark_eio(rq));
        intel_engine_signal_breadcrumbs(engine);

        /* Cancel and submit all pending requests. */
        list_for_each_entry(rq, &mock->hw_queue, mock.link) {
                if (i915_request_mark_eio(rq)) {
                        __i915_request_submit(rq);
                        i915_request_put(rq);
                }
        }
        INIT_LIST_HEAD(&mock->hw_queue);

        spin_unlock_irqrestore(&engine->sched_engine->lock, flags);
}

static void mock_reset_finish(struct intel_engine_cs *engine)
{
}

static void mock_engine_release(struct intel_engine_cs *engine)
{
        struct mock_engine *mock =
                container_of(engine, typeof(*mock), base);

        GEM_BUG_ON(timer_pending(&mock->hw_delay));

        i915_sched_engine_put(engine->sched_engine);
        intel_breadcrumbs_put(engine->breadcrumbs);

        intel_context_unpin(engine->kernel_context);
        intel_context_put(engine->kernel_context);

        intel_engine_fini_retire(engine);
}

struct intel_engine_cs *mock_engine(struct drm_i915_private *i915,
                                    const char *name,
                                    int id)
{
        struct mock_engine *engine;

        GEM_BUG_ON(id >= I915_NUM_ENGINES);
        GEM_BUG_ON(!to_gt(i915)->uncore);

        engine = kzalloc(sizeof(*engine) + PAGE_SIZE, GFP_KERNEL);
        if (!engine)
                return NULL;

        /* minimal engine setup for requests */
        engine->base.i915 = i915;
        engine->base.gt = to_gt(i915);
        engine->base.uncore = to_gt(i915)->uncore;
        snprintf(engine->base.name, sizeof(engine->base.name), "%s", name);
        engine->base.id = id;
        engine->base.mask = BIT(id);
        engine->base.legacy_idx = INVALID_ENGINE;
        engine->base.instance = id;
        engine->base.status_page.addr = (void *)(engine + 1);

        engine->base.cops = &mock_context_ops;
        engine->base.request_alloc = mock_request_alloc;
        engine->base.emit_flush = mock_emit_flush;
        engine->base.emit_fini_breadcrumb = mock_emit_breadcrumb;
        engine->base.submit_request = mock_submit_request;
        engine->base.add_active_request = mock_add_to_engine;
        engine->base.remove_active_request = mock_remove_from_engine;

        engine->base.reset.prepare = mock_reset_prepare;
        engine->base.reset.rewind = mock_reset_rewind;
        engine->base.reset.cancel = mock_reset_cancel;
        engine->base.reset.finish = mock_reset_finish;

        engine->base.release = mock_engine_release;

        to_gt(i915)->engine[id] = &engine->base;
        to_gt(i915)->engine_class[0][id] = &engine->base;

        /* fake hw queue */
        spin_lock_init(&engine->hw_lock);
        timer_setup(&engine->hw_delay, hw_delay_complete, 0);
        INIT_LIST_HEAD(&engine->hw_queue);

        intel_engine_add_user(&engine->base);

        return &engine->base;
}

int mock_engine_init(struct intel_engine_cs *engine)
{
        struct intel_context *ce;

        INIT_LIST_HEAD(&engine->pinned_contexts_list);

        engine->sched_engine = i915_sched_engine_create(ENGINE_MOCK);
        if (!engine->sched_engine)
                return -ENOMEM;
        engine->sched_engine->private_data = engine;

        intel_engine_init_execlists(engine);
        intel_engine_init__pm(engine);
        intel_engine_init_retire(engine);

        engine->breadcrumbs = intel_breadcrumbs_create(NULL);
        if (!engine->breadcrumbs)
                goto err_schedule;

        ce = create_kernel_context(engine);
        if (IS_ERR(ce))
                goto err_breadcrumbs;

        /* We insist the kernel context is using the status_page */
        engine->status_page.vma = ce->timeline->hwsp_ggtt;

        engine->kernel_context = ce;
        return 0;

err_breadcrumbs:
        intel_breadcrumbs_put(engine->breadcrumbs);
err_schedule:
        i915_sched_engine_put(engine->sched_engine);
        return -ENOMEM;
}

void mock_engine_flush(struct intel_engine_cs *engine)
{
        struct mock_engine *mock =
                container_of(engine, typeof(*mock), base);
        struct i915_request *request, *rn;

        timer_delete_sync(&mock->hw_delay);

        spin_lock_irq(&mock->hw_lock);
        list_for_each_entry_safe(request, rn, &mock->hw_queue, mock.link)
                advance(request);
        spin_unlock_irq(&mock->hw_lock);
}

void mock_engine_reset(struct intel_engine_cs *engine)
{
}