// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2011 Texas Instruments Incorporated - https://www.ti.com/
 * Author: Rob Clark <rob.clark@linaro.org>
 */

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

#include <drm/drm_prime.h>

#include "omap_drv.h"

MODULE_IMPORT_NS("DMA_BUF");

/* -----------------------------------------------------------------------------
 * DMABUF Export
 */

static struct sg_table *omap_gem_map_dma_buf(
                struct dma_buf_attachment *attachment,
                enum dma_data_direction dir)
{
        struct drm_gem_object *obj = attachment->dmabuf->priv;
        struct sg_table *sg;
        sg = omap_gem_get_sg(obj, dir);
        if (IS_ERR(sg))
                return sg;

        return sg;
}

static void omap_gem_unmap_dma_buf(struct dma_buf_attachment *attachment,
                struct sg_table *sg, enum dma_data_direction dir)
{
        struct drm_gem_object *obj = attachment->dmabuf->priv;
        omap_gem_put_sg(obj, sg);
}

static int omap_gem_dmabuf_begin_cpu_access(struct dma_buf *buffer,
                enum dma_data_direction dir)
{
        struct drm_gem_object *obj = buffer->priv;
        struct page **pages;
        if (omap_gem_flags(obj) & OMAP_BO_TILED_MASK) {
                /* TODO we would need to pin at least part of the buffer to
                 * get de-tiled view.  For now just reject it.
                 */
                return -ENOMEM;
        }
        /* make sure we have the pages: */
        return omap_gem_get_pages(obj, &pages, true);
}

static int omap_gem_dmabuf_end_cpu_access(struct dma_buf *buffer,
                                          enum dma_data_direction dir)
{
        struct drm_gem_object *obj = buffer->priv;
        omap_gem_put_pages(obj);
        return 0;
}

static int omap_gem_dmabuf_mmap(struct dma_buf *buffer,
                struct vm_area_struct *vma)
{
        struct drm_gem_object *obj = buffer->priv;

        return drm_gem_mmap_obj(obj, omap_gem_mmap_size(obj), vma);
}

static const struct dma_buf_ops omap_dmabuf_ops = {
        .map_dma_buf = omap_gem_map_dma_buf,
        .unmap_dma_buf = omap_gem_unmap_dma_buf,
        .release = drm_gem_dmabuf_release,
        .begin_cpu_access = omap_gem_dmabuf_begin_cpu_access,
        .end_cpu_access = omap_gem_dmabuf_end_cpu_access,
        .mmap = omap_gem_dmabuf_mmap,
};

struct dma_buf *omap_gem_prime_export(struct drm_gem_object *obj, int flags)
{
        DEFINE_DMA_BUF_EXPORT_INFO(exp_info);

        exp_info.ops = &omap_dmabuf_ops;
        exp_info.size = omap_gem_mmap_size(obj);
        exp_info.flags = flags;
        exp_info.priv = obj;
        exp_info.resv = obj->resv;

        return drm_gem_dmabuf_export(obj->dev, &exp_info);
}

/* -----------------------------------------------------------------------------
 * DMABUF Import
 */

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

        if (dma_buf->ops == &omap_dmabuf_ops) {
                obj = dma_buf->priv;
                if (obj->dev == dev) {
                        /*
                         * Importing dmabuf exported from out own gem increases
                         * refcount on gem itself instead of f_count of dmabuf.
                         */
                        drm_gem_object_get(obj);
                        return obj;
                }
        }

        attach = dma_buf_attach(dma_buf, dev->dev);
        if (IS_ERR(attach))
                return ERR_CAST(attach);

        get_dma_buf(dma_buf);

        sgt = dma_buf_map_attachment_unlocked(attach, DMA_TO_DEVICE);
        if (IS_ERR(sgt)) {
                ret = PTR_ERR(sgt);
                goto fail_detach;
        }

        obj = omap_gem_new_dmabuf(dev, dma_buf->size, sgt);
        if (IS_ERR(obj)) {
                ret = PTR_ERR(obj);
                goto fail_unmap;
        }

        obj->import_attach = attach;

        return obj;

fail_unmap:
        dma_buf_unmap_attachment_unlocked(attach, sgt, DMA_TO_DEVICE);
fail_detach:
        dma_buf_detach(dma_buf, attach);
        dma_buf_put(dma_buf);

        return ERR_PTR(ret);
}