/*
 * Copyright © 2016 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 *
 */

#include "mock_engine.h"
#include "mock_request.h"

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

static void advance(struct mock_engine *engine,
                    struct mock_request *request)
{
        list_del_init(&request->link);
        mock_seqno_advance(&engine->base, request->base.global_seqno);
}

static void hw_delay_complete(struct timer_list *t)
{
        struct mock_engine *engine = from_timer(engine, t, hw_delay);
        struct mock_request *request;

        spin_lock(&engine->hw_lock);

        /* Timer fired, first request is complete */
        request = first_request(engine);
        if (request)
                advance(engine, 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->delay) {
                        mod_timer(&engine->hw_delay, jiffies + request->delay);
                        break;
                }

                advance(engine, request);
        }

        spin_unlock(&engine->hw_lock);
}

static struct intel_ring *
mock_context_pin(struct intel_engine_cs *engine,
                 struct i915_gem_context *ctx)
{
        i915_gem_context_get(ctx);
        return engine->buffer;
}

static void mock_context_unpin(struct intel_engine_cs *engine,
                               struct i915_gem_context *ctx)
{
        i915_gem_context_put(ctx);
}

static int mock_request_alloc(struct i915_request *request)
{
        struct mock_request *mock = container_of(request, typeof(*mock), base);

        INIT_LIST_HEAD(&mock->link);
        mock->delay = 0;

        return 0;
}

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

static void mock_emit_breadcrumb(struct i915_request *request,
                                 u32 *flags)
{
}

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

        i915_request_submit(request);
        GEM_BUG_ON(!request->global_seqno);

        spin_lock_irq(&engine->hw_lock);
        list_add_tail(&mock->link, &engine->hw_queue);
        if (mock->link.prev == &engine->hw_queue) {
                if (mock->delay)
                        mod_timer(&engine->hw_delay, jiffies + mock->delay);
                else
                        advance(engine, mock);
        }
        spin_unlock_irq(&engine->hw_lock);
}

static struct intel_ring *mock_ring(struct intel_engine_cs *engine)
{
        const unsigned long sz = PAGE_SIZE / 2;
        struct intel_ring *ring;

        BUILD_BUG_ON(MIN_SPACE_FOR_ADD_REQUEST > sz);

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

        ring->size = sz;
        ring->effective_size = sz;
        ring->vaddr = (void *)(ring + 1);

        INIT_LIST_HEAD(&ring->request_list);
        intel_ring_update_space(ring);

        return ring;
}

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);

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

        engine->base.buffer = mock_ring(&engine->base);
        if (!engine->base.buffer) {
                kfree(engine);
                return NULL;
        }

        /* minimal engine setup for requests */
        engine->base.i915 = i915;
        snprintf(engine->base.name, sizeof(engine->base.name), "%s", name);
        engine->base.id = id;
        engine->base.status_page.page_addr = (void *)(engine + 1);

        engine->base.context_pin = mock_context_pin;
        engine->base.context_unpin = mock_context_unpin;
        engine->base.request_alloc = mock_request_alloc;
        engine->base.emit_flush = mock_emit_flush;
        engine->base.emit_breadcrumb = mock_emit_breadcrumb;
        engine->base.submit_request = mock_submit_request;

        engine->base.timeline =
                &i915->gt.global_timeline.engine[engine->base.id];

        intel_engine_init_breadcrumbs(&engine->base);
        engine->base.breadcrumbs.mock = true; /* prevent touching HW for irqs */

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

        return &engine->base;
}

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

        del_timer_sync(&mock->hw_delay);

        spin_lock_irq(&mock->hw_lock);
        list_for_each_entry_safe(request, rn, &mock->hw_queue, link) {
                list_del_init(&request->link);
                mock_seqno_advance(&mock->base, request->base.global_seqno);
        }
        spin_unlock_irq(&mock->hw_lock);
}

void mock_engine_reset(struct intel_engine_cs *engine)
{
        intel_write_status_page(engine, I915_GEM_HWS_INDEX, 0);
}

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

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

        if (engine->last_retired_context)
                engine->context_unpin(engine, engine->last_retired_context);

        intel_engine_fini_breadcrumbs(engine);

        kfree(engine->buffer);
        kfree(engine);
}