/*
 *  Copyright © 2015 Broadcom
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

/* DOC: VC4 GEM BO management support.
 *
 * The VC4 GPU architecture (both scanout and rendering) has direct
 * access to system memory with no MMU in between.  To support it, we
 * use the GEM CMA helper functions to allocate contiguous ranges of
 * physical memory for our BOs.
 *
 * Since the CMA allocator is very slow, we keep a cache of recently
 * freed BOs around so that the kernel's allocation of objects for 3D
 * rendering can return quickly.
 */

#include "vc4_drv.h"
#include "uapi/drm/vc4_drm.h"

static void vc4_bo_stats_dump(struct vc4_dev *vc4)
{
        DRM_INFO("num bos allocated: %d\n",
                 vc4->bo_stats.num_allocated);
        DRM_INFO("size bos allocated: %dkb\n",
                 vc4->bo_stats.size_allocated / 1024);
        DRM_INFO("num bos used: %d\n",
                 vc4->bo_stats.num_allocated - vc4->bo_stats.num_cached);
        DRM_INFO("size bos used: %dkb\n",
                 (vc4->bo_stats.size_allocated -
                  vc4->bo_stats.size_cached) / 1024);
        DRM_INFO("num bos cached: %d\n",
                 vc4->bo_stats.num_cached);
        DRM_INFO("size bos cached: %dkb\n",
                 vc4->bo_stats.size_cached / 1024);
}

#ifdef CONFIG_DEBUG_FS
int vc4_bo_stats_debugfs(struct seq_file *m, void *unused)
{
        struct drm_info_node *node = (struct drm_info_node *)m->private;
        struct drm_device *dev = node->minor->dev;
        struct vc4_dev *vc4 = to_vc4_dev(dev);
        struct vc4_bo_stats stats;

        /* Take a snapshot of the current stats with the lock held. */
        mutex_lock(&vc4->bo_lock);
        stats = vc4->bo_stats;
        mutex_unlock(&vc4->bo_lock);

        seq_printf(m, "num bos allocated: %d\n",
                   stats.num_allocated);
        seq_printf(m, "size bos allocated: %dkb\n",
                   stats.size_allocated / 1024);
        seq_printf(m, "num bos used: %d\n",
                   stats.num_allocated - stats.num_cached);
        seq_printf(m, "size bos used: %dkb\n",
                   (stats.size_allocated - stats.size_cached) / 1024);
        seq_printf(m, "num bos cached: %d\n",
                   stats.num_cached);
        seq_printf(m, "size bos cached: %dkb\n",
                   stats.size_cached / 1024);

        return 0;
}
#endif

static uint32_t bo_page_index(size_t size)
{
        return (size / PAGE_SIZE) - 1;
}

/* Must be called with bo_lock held. */
static void vc4_bo_destroy(struct vc4_bo *bo)
{
        struct drm_gem_object *obj = &bo->base.base;
        struct vc4_dev *vc4 = to_vc4_dev(obj->dev);

        if (bo->validated_shader) {
                kfree(bo->validated_shader->texture_samples);
                kfree(bo->validated_shader);
                bo->validated_shader = NULL;
        }

        vc4->bo_stats.num_allocated--;
        vc4->bo_stats.size_allocated -= obj->size;
        drm_gem_cma_free_object(obj);
}

/* Must be called with bo_lock held. */
static void vc4_bo_remove_from_cache(struct vc4_bo *bo)
{
        struct drm_gem_object *obj = &bo->base.base;
        struct vc4_dev *vc4 = to_vc4_dev(obj->dev);

        vc4->bo_stats.num_cached--;
        vc4->bo_stats.size_cached -= obj->size;

        list_del(&bo->unref_head);
        list_del(&bo->size_head);
}

static struct list_head *vc4_get_cache_list_for_size(struct drm_device *dev,
                                                     size_t size)
{
        struct vc4_dev *vc4 = to_vc4_dev(dev);
        uint32_t page_index = bo_page_index(size);

        if (vc4->bo_cache.size_list_size <= page_index) {
                uint32_t new_size = max(vc4->bo_cache.size_list_size * 2,
                                        page_index + 1);
                struct list_head *new_list;
                uint32_t i;

                new_list = kmalloc_array(new_size, sizeof(struct list_head),
                                         GFP_KERNEL);
                if (!new_list)
                        return NULL;

                /* Rebase the old cached BO lists to their new list
                 * head locations.
                 */
                for (i = 0; i < vc4->bo_cache.size_list_size; i++) {
                        struct list_head *old_list =
                                &vc4->bo_cache.size_list[i];

                        if (list_empty(old_list))
                                INIT_LIST_HEAD(&new_list[i]);
                        else
                                list_replace(old_list, &new_list[i]);
                }
                /* And initialize the brand new BO list heads. */
                for (i = vc4->bo_cache.size_list_size; i < new_size; i++)
                        INIT_LIST_HEAD(&new_list[i]);

                kfree(vc4->bo_cache.size_list);
                vc4->bo_cache.size_list = new_list;
                vc4->bo_cache.size_list_size = new_size;
        }

        return &vc4->bo_cache.size_list[page_index];
}

void vc4_bo_cache_purge(struct drm_device *dev)
{
        struct vc4_dev *vc4 = to_vc4_dev(dev);

        mutex_lock(&vc4->bo_lock);
        while (!list_empty(&vc4->bo_cache.time_list)) {
                struct vc4_bo *bo = list_last_entry(&vc4->bo_cache.time_list,
                                                    struct vc4_bo, unref_head);
                vc4_bo_remove_from_cache(bo);
                vc4_bo_destroy(bo);
        }
        mutex_unlock(&vc4->bo_lock);
}

static struct vc4_bo *vc4_bo_get_from_cache(struct drm_device *dev,
                                            uint32_t size)
{
        struct vc4_dev *vc4 = to_vc4_dev(dev);
        uint32_t page_index = bo_page_index(size);
        struct vc4_bo *bo = NULL;

        size = roundup(size, PAGE_SIZE);

        mutex_lock(&vc4->bo_lock);
        if (page_index >= vc4->bo_cache.size_list_size)
                goto out;

        if (list_empty(&vc4->bo_cache.size_list[page_index]))
                goto out;

        bo = list_first_entry(&vc4->bo_cache.size_list[page_index],
                              struct vc4_bo, size_head);
        vc4_bo_remove_from_cache(bo);
        kref_init(&bo->base.base.refcount);

out:
        mutex_unlock(&vc4->bo_lock);
        return bo;
}

/**
 * vc4_gem_create_object - Implementation of driver->gem_create_object.
 *
 * This lets the CMA helpers allocate object structs for us, and keep
 * our BO stats correct.
 */
struct drm_gem_object *vc4_create_object(struct drm_device *dev, size_t size)
{
        struct vc4_dev *vc4 = to_vc4_dev(dev);
        struct vc4_bo *bo;

        bo = kzalloc(sizeof(*bo), GFP_KERNEL);
        if (!bo)
                return ERR_PTR(-ENOMEM);

        mutex_lock(&vc4->bo_lock);
        vc4->bo_stats.num_allocated++;
        vc4->bo_stats.size_allocated += size;
        mutex_unlock(&vc4->bo_lock);

        return &bo->base.base;
}

struct vc4_bo *vc4_bo_create(struct drm_device *dev, size_t unaligned_size,
                             bool from_cache)
{
        size_t size = roundup(unaligned_size, PAGE_SIZE);
        struct vc4_dev *vc4 = to_vc4_dev(dev);
        struct drm_gem_cma_object *cma_obj;

        if (size == 0)
                return ERR_PTR(-EINVAL);

        /* First, try to get a vc4_bo from the kernel BO cache. */
        if (from_cache) {
                struct vc4_bo *bo = vc4_bo_get_from_cache(dev, size);

                if (bo)
                        return bo;
        }

        cma_obj = drm_gem_cma_create(dev, size);
        if (IS_ERR(cma_obj)) {
                /*
                 * If we've run out of CMA memory, kill the cache of
                 * CMA allocations we've got laying around and try again.
                 */
                vc4_bo_cache_purge(dev);

                cma_obj = drm_gem_cma_create(dev, size);
                if (IS_ERR(cma_obj)) {
                        DRM_ERROR("Failed to allocate from CMA:\n");
                        vc4_bo_stats_dump(vc4);
                        return ERR_PTR(-ENOMEM);
                }
        }

        return to_vc4_bo(&cma_obj->base);
}

int vc4_dumb_create(struct drm_file *file_priv,
                    struct drm_device *dev,
                    struct drm_mode_create_dumb *args)
{
        int min_pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
        struct vc4_bo *bo = NULL;
        int ret;

        if (args->pitch < min_pitch)
                args->pitch = min_pitch;

        if (args->size < args->pitch * args->height)
                args->size = args->pitch * args->height;

        bo = vc4_bo_create(dev, args->size, false);
        if (IS_ERR(bo))
                return PTR_ERR(bo);

        ret = drm_gem_handle_create(file_priv, &bo->base.base, &args->handle);
        drm_gem_object_unreference_unlocked(&bo->base.base);

        return ret;
}

/* Must be called with bo_lock held. */
static void vc4_bo_cache_free_old(struct drm_device *dev)
{
        struct vc4_dev *vc4 = to_vc4_dev(dev);
        unsigned long expire_time = jiffies - msecs_to_jiffies(1000);

        while (!list_empty(&vc4->bo_cache.time_list)) {
                struct vc4_bo *bo = list_last_entry(&vc4->bo_cache.time_list,
                                                    struct vc4_bo, unref_head);
                if (time_before(expire_time, bo->free_time)) {
                        mod_timer(&vc4->bo_cache.time_timer,
                                  round_jiffies_up(jiffies +
                                                   msecs_to_jiffies(1000)));
                        return;
                }

                vc4_bo_remove_from_cache(bo);
                vc4_bo_destroy(bo);
        }
}

/* Called on the last userspace/kernel unreference of the BO.  Returns
 * it to the BO cache if possible, otherwise frees it.
 *
 * Note that this is called with the struct_mutex held.
 */
void vc4_free_object(struct drm_gem_object *gem_bo)
{
        struct drm_device *dev = gem_bo->dev;
        struct vc4_dev *vc4 = to_vc4_dev(dev);
        struct vc4_bo *bo = to_vc4_bo(gem_bo);
        struct list_head *cache_list;

        mutex_lock(&vc4->bo_lock);
        /* If the object references someone else's memory, we can't cache it.
         */
        if (gem_bo->import_attach) {
                vc4_bo_destroy(bo);
                goto out;
        }

        /* Don't cache if it was publicly named. */
        if (gem_bo->name) {
                vc4_bo_destroy(bo);
                goto out;
        }

        cache_list = vc4_get_cache_list_for_size(dev, gem_bo->size);
        if (!cache_list) {
                vc4_bo_destroy(bo);
                goto out;
        }

        if (bo->validated_shader) {
                kfree(bo->validated_shader->texture_samples);
                kfree(bo->validated_shader);
                bo->validated_shader = NULL;
        }

        bo->free_time = jiffies;
        list_add(&bo->size_head, cache_list);
        list_add(&bo->unref_head, &vc4->bo_cache.time_list);

        vc4->bo_stats.num_cached++;
        vc4->bo_stats.size_cached += gem_bo->size;

        vc4_bo_cache_free_old(dev);

out:
        mutex_unlock(&vc4->bo_lock);
}

static void vc4_bo_cache_time_work(struct work_struct *work)
{
        struct vc4_dev *vc4 =
                container_of(work, struct vc4_dev, bo_cache.time_work);
        struct drm_device *dev = vc4->dev;

        mutex_lock(&vc4->bo_lock);
        vc4_bo_cache_free_old(dev);
        mutex_unlock(&vc4->bo_lock);
}

static void vc4_bo_cache_time_timer(unsigned long data)
{
        struct drm_device *dev = (struct drm_device *)data;
        struct vc4_dev *vc4 = to_vc4_dev(dev);

        schedule_work(&vc4->bo_cache.time_work);
}

struct dma_buf *
vc4_prime_export(struct drm_device *dev, struct drm_gem_object *obj, int flags)
{
        struct vc4_bo *bo = to_vc4_bo(obj);

        if (bo->validated_shader) {
                DRM_ERROR("Attempting to export shader BO\n");
                return ERR_PTR(-EINVAL);
        }

        return drm_gem_prime_export(dev, obj, flags);
}

int vc4_mmap(struct file *filp, struct vm_area_struct *vma)
{
        struct drm_gem_object *gem_obj;
        struct vc4_bo *bo;
        int ret;

        ret = drm_gem_mmap(filp, vma);
        if (ret)
                return ret;

        gem_obj = vma->vm_private_data;
        bo = to_vc4_bo(gem_obj);

        if (bo->validated_shader && (vma->vm_flags & VM_WRITE)) {
                DRM_ERROR("mmaping of shader BOs for writing not allowed.\n");
                return -EINVAL;
        }

        /*
         * Clear the VM_PFNMAP flag that was set by drm_gem_mmap(), and set the
         * vm_pgoff (used as a fake buffer offset by DRM) to 0 as we want to map
         * the whole buffer.
         */
        vma->vm_flags &= ~VM_PFNMAP;
        vma->vm_pgoff = 0;

        ret = dma_mmap_wc(bo->base.base.dev->dev, vma, bo->base.vaddr,
                          bo->base.paddr, vma->vm_end - vma->vm_start);
        if (ret)
                drm_gem_vm_close(vma);

        return ret;
}

int vc4_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
{
        struct vc4_bo *bo = to_vc4_bo(obj);

        if (bo->validated_shader && (vma->vm_flags & VM_WRITE)) {
                DRM_ERROR("mmaping of shader BOs for writing not allowed.\n");
                return -EINVAL;
        }

        return drm_gem_cma_prime_mmap(obj, vma);
}

void *vc4_prime_vmap(struct drm_gem_object *obj)
{
        struct vc4_bo *bo = to_vc4_bo(obj);

        if (bo->validated_shader) {
                DRM_ERROR("mmaping of shader BOs not allowed.\n");
                return ERR_PTR(-EINVAL);
        }

        return drm_gem_cma_prime_vmap(obj);
}

int vc4_create_bo_ioctl(struct drm_device *dev, void *data,
                        struct drm_file *file_priv)
{
        struct drm_vc4_create_bo *args = data;
        struct vc4_bo *bo = NULL;
        int ret;

        /*
         * We can't allocate from the BO cache, because the BOs don't
         * get zeroed, and that might leak data between users.
         */
        bo = vc4_bo_create(dev, args->size, false);
        if (IS_ERR(bo))
                return PTR_ERR(bo);

        ret = drm_gem_handle_create(file_priv, &bo->base.base, &args->handle);
        drm_gem_object_unreference_unlocked(&bo->base.base);

        return ret;
}

int vc4_mmap_bo_ioctl(struct drm_device *dev, void *data,
                      struct drm_file *file_priv)
{
        struct drm_vc4_mmap_bo *args = data;
        struct drm_gem_object *gem_obj;

        gem_obj = drm_gem_object_lookup(dev, file_priv, args->handle);
        if (!gem_obj) {
                DRM_ERROR("Failed to look up GEM BO %d\n", args->handle);
                return -EINVAL;
        }

        /* The mmap offset was set up at BO allocation time. */
        args->offset = drm_vma_node_offset_addr(&gem_obj->vma_node);

        drm_gem_object_unreference_unlocked(gem_obj);
        return 0;
}

int
vc4_create_shader_bo_ioctl(struct drm_device *dev, void *data,
                           struct drm_file *file_priv)
{
        struct drm_vc4_create_shader_bo *args = data;
        struct vc4_bo *bo = NULL;
        int ret;

        if (args->size == 0)
                return -EINVAL;

        if (args->size % sizeof(u64) != 0)
                return -EINVAL;

        if (args->flags != 0) {
                DRM_INFO("Unknown flags set: 0x%08x\n", args->flags);
                return -EINVAL;
        }

        if (args->pad != 0) {
                DRM_INFO("Pad set: 0x%08x\n", args->pad);
                return -EINVAL;
        }

        bo = vc4_bo_create(dev, args->size, true);
        if (IS_ERR(bo))
                return PTR_ERR(bo);

        if (copy_from_user(bo->base.vaddr,
                             (void __user *)(uintptr_t)args->data,
                             args->size)) {
                ret = -EFAULT;
                goto fail;
        }
        /* Clear the rest of the memory from allocating from the BO
         * cache.
         */
        memset(bo->base.vaddr + args->size, 0,
               bo->base.base.size - args->size);

        bo->validated_shader = vc4_validate_shader(&bo->base);
        if (!bo->validated_shader) {
                ret = -EINVAL;
                goto fail;
        }

        /* We have to create the handle after validation, to avoid
         * races for users to do doing things like mmap the shader BO.
         */
        ret = drm_gem_handle_create(file_priv, &bo->base.base, &args->handle);

 fail:
        drm_gem_object_unreference_unlocked(&bo->base.base);

        return ret;
}

void vc4_bo_cache_init(struct drm_device *dev)
{
        struct vc4_dev *vc4 = to_vc4_dev(dev);

        mutex_init(&vc4->bo_lock);

        INIT_LIST_HEAD(&vc4->bo_cache.time_list);

        INIT_WORK(&vc4->bo_cache.time_work, vc4_bo_cache_time_work);
        setup_timer(&vc4->bo_cache.time_timer,
                    vc4_bo_cache_time_timer,
                    (unsigned long)dev);
}

void vc4_bo_cache_destroy(struct drm_device *dev)
{
        struct vc4_dev *vc4 = to_vc4_dev(dev);

        del_timer(&vc4->bo_cache.time_timer);
        cancel_work_sync(&vc4->bo_cache.time_work);

        vc4_bo_cache_purge(dev);

        if (vc4->bo_stats.num_allocated) {
                DRM_ERROR("Destroying BO cache while BOs still allocated:\n");
                vc4_bo_stats_dump(vc4);
        }
}