/*
 * Copyright © 2017 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 "display/intel_frontbuffer.h"

#include "i915_drv.h"
#include "i915_gem_clflush.h"
#include "i915_gem_context.h"
#include "i915_gem_object.h"
#include "i915_globals.h"

static struct i915_global_object {
        struct i915_global base;
        struct kmem_cache *slab_objects;
} global;

struct drm_i915_gem_object *i915_gem_object_alloc(void)
{
        return kmem_cache_zalloc(global.slab_objects, GFP_KERNEL);
}

void i915_gem_object_free(struct drm_i915_gem_object *obj)
{
        return kmem_cache_free(global.slab_objects, obj);
}

static void
frontbuffer_retire(struct i915_active_request *active,
                   struct i915_request *request)
{
        struct drm_i915_gem_object *obj =
                container_of(active, typeof(*obj), frontbuffer_write);

        intel_fb_obj_flush(obj, ORIGIN_CS);
}

void i915_gem_object_init(struct drm_i915_gem_object *obj,
                          const struct drm_i915_gem_object_ops *ops)
{
        mutex_init(&obj->mm.lock);

        spin_lock_init(&obj->vma.lock);
        INIT_LIST_HEAD(&obj->vma.list);

        INIT_LIST_HEAD(&obj->lut_list);
        INIT_LIST_HEAD(&obj->batch_pool_link);

        init_rcu_head(&obj->rcu);

        obj->ops = ops;

        obj->frontbuffer_ggtt_origin = ORIGIN_GTT;
        i915_active_request_init(&obj->frontbuffer_write,
                                 NULL, frontbuffer_retire);

        obj->mm.madv = I915_MADV_WILLNEED;
        INIT_RADIX_TREE(&obj->mm.get_page.radix, GFP_KERNEL | __GFP_NOWARN);
        mutex_init(&obj->mm.get_page.lock);
}

/**
 * Mark up the object's coherency levels for a given cache_level
 * @obj: #drm_i915_gem_object
 * @cache_level: cache level
 */
void i915_gem_object_set_cache_coherency(struct drm_i915_gem_object *obj,
                                         unsigned int cache_level)
{
        obj->cache_level = cache_level;

        if (cache_level != I915_CACHE_NONE)
                obj->cache_coherent = (I915_BO_CACHE_COHERENT_FOR_READ |
                                       I915_BO_CACHE_COHERENT_FOR_WRITE);
        else if (HAS_LLC(to_i915(obj->base.dev)))
                obj->cache_coherent = I915_BO_CACHE_COHERENT_FOR_READ;
        else
                obj->cache_coherent = 0;

        obj->cache_dirty =
                !(obj->cache_coherent & I915_BO_CACHE_COHERENT_FOR_WRITE);
}

void i915_gem_close_object(struct drm_gem_object *gem, struct drm_file *file)
{
        struct drm_i915_gem_object *obj = to_intel_bo(gem);
        struct drm_i915_file_private *fpriv = file->driver_priv;
        struct i915_lut_handle *lut, *ln;
        LIST_HEAD(close);

        i915_gem_object_lock(obj);
        list_for_each_entry_safe(lut, ln, &obj->lut_list, obj_link) {
                struct i915_gem_context *ctx = lut->ctx;

                if (ctx->file_priv != fpriv)
                        continue;

                i915_gem_context_get(ctx);
                list_move(&lut->obj_link, &close);
        }
        i915_gem_object_unlock(obj);

        list_for_each_entry_safe(lut, ln, &close, obj_link) {
                struct i915_gem_context *ctx = lut->ctx;
                struct i915_vma *vma;

                /*
                 * We allow the process to have multiple handles to the same
                 * vma, in the same fd namespace, by virtue of flink/open.
                 */

                mutex_lock(&ctx->mutex);
                vma = radix_tree_delete(&ctx->handles_vma, lut->handle);
                if (vma) {
                        GEM_BUG_ON(vma->obj != obj);
                        GEM_BUG_ON(!atomic_read(&vma->open_count));
                        if (atomic_dec_and_test(&vma->open_count) &&
                            !i915_vma_is_ggtt(vma))
                                i915_vma_close(vma);
                }
                mutex_unlock(&ctx->mutex);

                i915_gem_context_put(lut->ctx);
                i915_lut_handle_free(lut);
                i915_gem_object_put(obj);
        }
}

static void __i915_gem_free_objects(struct drm_i915_private *i915,
                                    struct llist_node *freed)
{
        struct drm_i915_gem_object *obj, *on;
        intel_wakeref_t wakeref;

        wakeref = intel_runtime_pm_get(&i915->runtime_pm);
        llist_for_each_entry_safe(obj, on, freed, freed) {
                struct i915_vma *vma, *vn;

                trace_i915_gem_object_destroy(obj);

                mutex_lock(&i915->drm.struct_mutex);

                GEM_BUG_ON(i915_gem_object_is_active(obj));
                list_for_each_entry_safe(vma, vn, &obj->vma.list, obj_link) {
                        GEM_BUG_ON(i915_vma_is_active(vma));
                        vma->flags &= ~I915_VMA_PIN_MASK;
                        i915_vma_destroy(vma);
                }
                GEM_BUG_ON(!list_empty(&obj->vma.list));
                GEM_BUG_ON(!RB_EMPTY_ROOT(&obj->vma.tree));

                /*
                 * This serializes freeing with the shrinker. Since the free
                 * is delayed, first by RCU then by the workqueue, we want the
                 * shrinker to be able to free pages of unreferenced objects,
                 * or else we may oom whilst there are plenty of deferred
                 * freed objects.
                 */
                if (i915_gem_object_has_pages(obj) &&
                    i915_gem_object_is_shrinkable(obj)) {
                        unsigned long flags;

                        spin_lock_irqsave(&i915->mm.obj_lock, flags);
                        list_del_init(&obj->mm.link);
                        spin_unlock_irqrestore(&i915->mm.obj_lock, flags);
                }

                mutex_unlock(&i915->drm.struct_mutex);

                GEM_BUG_ON(atomic_read(&obj->bind_count));
                GEM_BUG_ON(obj->userfault_count);
                GEM_BUG_ON(atomic_read(&obj->frontbuffer_bits));
                GEM_BUG_ON(!list_empty(&obj->lut_list));

                if (obj->ops->release)
                        obj->ops->release(obj);

                atomic_set(&obj->mm.pages_pin_count, 0);
                __i915_gem_object_put_pages(obj, I915_MM_NORMAL);
                GEM_BUG_ON(i915_gem_object_has_pages(obj));

                if (obj->base.import_attach)
                        drm_prime_gem_destroy(&obj->base, NULL);

                drm_gem_object_release(&obj->base);

                bitmap_free(obj->bit_17);
                i915_gem_object_free(obj);

                GEM_BUG_ON(!atomic_read(&i915->mm.free_count));
                atomic_dec(&i915->mm.free_count);

                cond_resched();
        }
        intel_runtime_pm_put(&i915->runtime_pm, wakeref);
}

void i915_gem_flush_free_objects(struct drm_i915_private *i915)
{
        struct llist_node *freed;

        /* Free the oldest, most stale object to keep the free_list short */
        freed = NULL;
        if (!llist_empty(&i915->mm.free_list)) { /* quick test for hotpath */
                /* Only one consumer of llist_del_first() allowed */
                spin_lock(&i915->mm.free_lock);
                freed = llist_del_first(&i915->mm.free_list);
                spin_unlock(&i915->mm.free_lock);
        }
        if (unlikely(freed)) {
                freed->next = NULL;
                __i915_gem_free_objects(i915, freed);
        }
}

static void __i915_gem_free_work(struct work_struct *work)
{
        struct drm_i915_private *i915 =
                container_of(work, struct drm_i915_private, mm.free_work);
        struct llist_node *freed;

        /*
         * All file-owned VMA should have been released by this point through
         * i915_gem_close_object(), or earlier by i915_gem_context_close().
         * However, the object may also be bound into the global GTT (e.g.
         * older GPUs without per-process support, or for direct access through
         * the GTT either for the user or for scanout). Those VMA still need to
         * unbound now.
         */

        spin_lock(&i915->mm.free_lock);
        while ((freed = llist_del_all(&i915->mm.free_list))) {
                spin_unlock(&i915->mm.free_lock);

                __i915_gem_free_objects(i915, freed);
                if (need_resched())
                        return;

                spin_lock(&i915->mm.free_lock);
        }
        spin_unlock(&i915->mm.free_lock);
}

static void __i915_gem_free_object_rcu(struct rcu_head *head)
{
        struct drm_i915_gem_object *obj =
                container_of(head, typeof(*obj), rcu);
        struct drm_i915_private *i915 = to_i915(obj->base.dev);

        /*
         * We reuse obj->rcu for the freed list, so we had better not treat
         * it like a rcu_head from this point forwards. And we expect all
         * objects to be freed via this path.
         */
        destroy_rcu_head(&obj->rcu);

        /*
         * Since we require blocking on struct_mutex to unbind the freed
         * object from the GPU before releasing resources back to the
         * system, we can not do that directly from the RCU callback (which may
         * be a softirq context), but must instead then defer that work onto a
         * kthread. We use the RCU callback rather than move the freed object
         * directly onto the work queue so that we can mix between using the
         * worker and performing frees directly from subsequent allocations for
         * crude but effective memory throttling.
         */
        if (llist_add(&obj->freed, &i915->mm.free_list))
                queue_work(i915->wq, &i915->mm.free_work);
}

void i915_gem_free_object(struct drm_gem_object *gem_obj)
{
        struct drm_i915_gem_object *obj = to_intel_bo(gem_obj);

        /*
         * Before we free the object, make sure any pure RCU-only
         * read-side critical sections are complete, e.g.
         * i915_gem_busy_ioctl(). For the corresponding synchronized
         * lookup see i915_gem_object_lookup_rcu().
         */
        atomic_inc(&to_i915(obj->base.dev)->mm.free_count);
        call_rcu(&obj->rcu, __i915_gem_free_object_rcu);
}

static inline enum fb_op_origin
fb_write_origin(struct drm_i915_gem_object *obj, unsigned int domain)
{
        return (domain == I915_GEM_DOMAIN_GTT ?
                obj->frontbuffer_ggtt_origin : ORIGIN_CPU);
}

static bool gpu_write_needs_clflush(struct drm_i915_gem_object *obj)
{
        return !(obj->cache_level == I915_CACHE_NONE ||
                 obj->cache_level == I915_CACHE_WT);
}

void
i915_gem_object_flush_write_domain(struct drm_i915_gem_object *obj,
                                   unsigned int flush_domains)
{
        struct drm_i915_private *dev_priv = to_i915(obj->base.dev);
        struct i915_vma *vma;

        assert_object_held(obj);

        if (!(obj->write_domain & flush_domains))
                return;

        switch (obj->write_domain) {
        case I915_GEM_DOMAIN_GTT:
                i915_gem_flush_ggtt_writes(dev_priv);

                intel_fb_obj_flush(obj,
                                   fb_write_origin(obj, I915_GEM_DOMAIN_GTT));

                for_each_ggtt_vma(vma, obj) {
                        if (vma->iomap)
                                continue;

                        i915_vma_unset_ggtt_write(vma);
                }
                break;

        case I915_GEM_DOMAIN_WC:
                wmb();
                break;

        case I915_GEM_DOMAIN_CPU:
                i915_gem_clflush_object(obj, I915_CLFLUSH_SYNC);
                break;

        case I915_GEM_DOMAIN_RENDER:
                if (gpu_write_needs_clflush(obj))
                        obj->cache_dirty = true;
                break;
        }

        obj->write_domain = 0;
}

void i915_gem_init__objects(struct drm_i915_private *i915)
{
        INIT_WORK(&i915->mm.free_work, __i915_gem_free_work);
}

static void i915_global_objects_shrink(void)
{
        kmem_cache_shrink(global.slab_objects);
}

static void i915_global_objects_exit(void)
{
        kmem_cache_destroy(global.slab_objects);
}

static struct i915_global_object global = { {
        .shrink = i915_global_objects_shrink,
        .exit = i915_global_objects_exit,
} };

int __init i915_global_objects_init(void)
{
        global.slab_objects =
                KMEM_CACHE(drm_i915_gem_object, SLAB_HWCACHE_ALIGN);
        if (!global.slab_objects)
                return -ENOMEM;

        i915_global_register(&global.base);
        return 0;
}

#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
#include "selftests/huge_gem_object.c"
#include "selftests/huge_pages.c"
#include "selftests/i915_gem_object.c"
#include "selftests/i915_gem_coherency.c"
#endif