// SPDX-License-Identifier: GPL-2.0+
/* Copyright (C) 2015-2018 Broadcom */

/**
 * DOC: V3D GEM BO management support
 *
 * Compared to VC4 (V3D 2.x), V3D 3.3 introduces an MMU between the
 * GPU and the bus, allowing us to use shmem objects for our storage
 * instead of CMA.
 *
 * Physically contiguous objects may still be imported to V3D, but the
 * driver doesn't allocate physically contiguous objects on its own.
 * Display engines requiring physically contiguous allocations should
 * look into Mesa's "renderonly" support (as used by the Mesa pl111
 * driver) for an example of how to integrate with V3D.
 *
 * Long term, we should support evicting pages from the MMU when under
 * memory pressure (thus the v3d_bo_get_pages() refcounting), but
 * that's not a high priority since our systems tend to not have swap.
 */

#include <linux/dma-buf.h>
#include <linux/pfn_t.h>

#include "v3d_drv.h"
#include "uapi/drm/v3d_drm.h"

/* Called DRM core on the last userspace/kernel unreference of the
 * BO.
 */
void v3d_free_object(struct drm_gem_object *obj)
{
        struct v3d_dev *v3d = to_v3d_dev(obj->dev);
        struct v3d_bo *bo = to_v3d_bo(obj);

        v3d_mmu_remove_ptes(bo);

        mutex_lock(&v3d->bo_lock);
        v3d->bo_stats.num_allocated--;
        v3d->bo_stats.pages_allocated -= obj->size >> PAGE_SHIFT;
        mutex_unlock(&v3d->bo_lock);

        spin_lock(&v3d->mm_lock);
        drm_mm_remove_node(&bo->node);
        spin_unlock(&v3d->mm_lock);

        /* GPU execution may have dirtied any pages in the BO. */
        bo->base.pages_mark_dirty_on_put = true;

        drm_gem_shmem_free_object(obj);
}

static const struct drm_gem_object_funcs v3d_gem_funcs = {
        .free = v3d_free_object,
        .print_info = drm_gem_shmem_print_info,
        .pin = drm_gem_shmem_pin,
        .unpin = drm_gem_shmem_unpin,
        .get_sg_table = drm_gem_shmem_get_sg_table,
        .vmap = drm_gem_shmem_vmap,
        .vunmap = drm_gem_shmem_vunmap,
        .mmap = drm_gem_shmem_mmap,
};

/* gem_create_object function for allocating a BO struct and doing
 * early setup.
 */
struct drm_gem_object *v3d_create_object(struct drm_device *dev, size_t size)
{
        struct v3d_bo *bo;
        struct drm_gem_object *obj;

        if (size == 0)
                return NULL;

        bo = kzalloc(sizeof(*bo), GFP_KERNEL);
        if (!bo)
                return NULL;
        obj = &bo->base.base;

        obj->funcs = &v3d_gem_funcs;
        bo->base.map_wc = true;
        INIT_LIST_HEAD(&bo->unref_head);

        return &bo->base.base;
}

static int
v3d_bo_create_finish(struct drm_gem_object *obj)
{
        struct v3d_dev *v3d = to_v3d_dev(obj->dev);
        struct v3d_bo *bo = to_v3d_bo(obj);
        struct sg_table *sgt;
        int ret;

        /* So far we pin the BO in the MMU for its lifetime, so use
         * shmem's helper for getting a lifetime sgt.
         */
        sgt = drm_gem_shmem_get_pages_sgt(&bo->base.base);
        if (IS_ERR(sgt))
                return PTR_ERR(sgt);

        spin_lock(&v3d->mm_lock);
        /* Allocate the object's space in the GPU's page tables.
         * Inserting PTEs will happen later, but the offset is for the
         * lifetime of the BO.
         */
        ret = drm_mm_insert_node_generic(&v3d->mm, &bo->node,
                                         obj->size >> PAGE_SHIFT,
                                         GMP_GRANULARITY >> PAGE_SHIFT, 0, 0);
        spin_unlock(&v3d->mm_lock);
        if (ret)
                return ret;

        /* Track stats for /debug/dri/n/bo_stats. */
        mutex_lock(&v3d->bo_lock);
        v3d->bo_stats.num_allocated++;
        v3d->bo_stats.pages_allocated += obj->size >> PAGE_SHIFT;
        mutex_unlock(&v3d->bo_lock);

        v3d_mmu_insert_ptes(bo);

        return 0;
}

struct v3d_bo *v3d_bo_create(struct drm_device *dev, struct drm_file *file_priv,
                             size_t unaligned_size)
{
        struct drm_gem_shmem_object *shmem_obj;
        struct v3d_bo *bo;
        int ret;

        shmem_obj = drm_gem_shmem_create(dev, unaligned_size);
        if (IS_ERR(shmem_obj))
                return ERR_CAST(shmem_obj);
        bo = to_v3d_bo(&shmem_obj->base);

        ret = v3d_bo_create_finish(&shmem_obj->base);
        if (ret)
                goto free_obj;

        return bo;

free_obj:
        drm_gem_shmem_free_object(&shmem_obj->base);
        return ERR_PTR(ret);
}

struct drm_gem_object *
v3d_prime_import_sg_table(struct drm_device *dev,
                          struct dma_buf_attachment *attach,
                          struct sg_table *sgt)
{
        struct drm_gem_object *obj;
        int ret;

        obj = drm_gem_shmem_prime_import_sg_table(dev, attach, sgt);
        if (IS_ERR(obj))
                return obj;

        ret = v3d_bo_create_finish(obj);
        if (ret) {
                drm_gem_shmem_free_object(obj);
                return ERR_PTR(ret);
        }

        return obj;
}

int v3d_create_bo_ioctl(struct drm_device *dev, void *data,
                        struct drm_file *file_priv)
{
        struct drm_v3d_create_bo *args = data;
        struct v3d_bo *bo = NULL;
        int ret;

        if (args->flags != 0) {
                DRM_INFO("unknown create_bo flags: %d\n", args->flags);
                return -EINVAL;
        }

        bo = v3d_bo_create(dev, file_priv, PAGE_ALIGN(args->size));
        if (IS_ERR(bo))
                return PTR_ERR(bo);

        args->offset = bo->node.start << PAGE_SHIFT;

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

        return ret;
}

int v3d_mmap_bo_ioctl(struct drm_device *dev, void *data,
                      struct drm_file *file_priv)
{
        struct drm_v3d_mmap_bo *args = data;
        struct drm_gem_object *gem_obj;

        if (args->flags != 0) {
                DRM_INFO("unknown mmap_bo flags: %d\n", args->flags);
                return -EINVAL;
        }

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

        args->offset = drm_vma_node_offset_addr(&gem_obj->vma_node);
        drm_gem_object_put(gem_obj);

        return 0;
}

int v3d_get_bo_offset_ioctl(struct drm_device *dev, void *data,
                            struct drm_file *file_priv)
{
        struct drm_v3d_get_bo_offset *args = data;
        struct drm_gem_object *gem_obj;
        struct v3d_bo *bo;

        gem_obj = drm_gem_object_lookup(file_priv, args->handle);
        if (!gem_obj) {
                DRM_DEBUG("Failed to look up GEM BO %d\n", args->handle);
                return -ENOENT;
        }
        bo = to_v3d_bo(gem_obj);

        args->offset = bo->node.start << PAGE_SHIFT;

        drm_gem_object_put(gem_obj);
        return 0;
}