drm/omapdrm/omap_gem_dmabuf.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * Copyright (C) 2011 Texas Instruments Incorporated - https://www.ti.com/
0004  * Author: Rob Clark <rob.clark@linaro.org>
0005  */
0006
0007 #include <linux/dma-buf.h>
0008 #include <linux/highmem.h>
0009
0010 #include <drm/drm_prime.h>
0011
0012 #include "omap_drv.h"
0013
0014 MODULE_IMPORT_NS(DMA_BUF);
0015
0016 /* -----------------------------------------------------------------------------
0017  * DMABUF Export
0018  */
0019
0020 static struct sg_table *omap_gem_map_dma_buf(
0021         struct dma_buf_attachment *attachment,
0022         enum dma_data_direction dir)
0023 {
0024     struct drm_gem_object *obj = attachment->dmabuf->priv;
0025     struct sg_table *sg;
0026     sg = omap_gem_get_sg(obj, dir);
0027     if (IS_ERR(sg))
0028         return sg;
0029
0030     return sg;
0031 }
0032
0033 static void omap_gem_unmap_dma_buf(struct dma_buf_attachment *attachment,
0034         struct sg_table *sg, enum dma_data_direction dir)
0035 {
0036     struct drm_gem_object *obj = attachment->dmabuf->priv;
0037     omap_gem_put_sg(obj, sg);
0038 }
0039
0040 static int omap_gem_dmabuf_begin_cpu_access(struct dma_buf *buffer,
0041         enum dma_data_direction dir)
0042 {
0043     struct drm_gem_object *obj = buffer->priv;
0044     struct page **pages;
0045     if (omap_gem_flags(obj) & OMAP_BO_TILED_MASK) {
0046         /* TODO we would need to pin at least part of the buffer to
0047          * get de-tiled view.  For now just reject it.
0048          */
0049         return -ENOMEM;
0050     }
0051     /* make sure we have the pages: */
0052     return omap_gem_get_pages(obj, &pages, true);
0053 }
0054
0055 static int omap_gem_dmabuf_end_cpu_access(struct dma_buf *buffer,
0056                       enum dma_data_direction dir)
0057 {
0058     struct drm_gem_object *obj = buffer->priv;
0059     omap_gem_put_pages(obj);
0060     return 0;
0061 }
0062
0063 static int omap_gem_dmabuf_mmap(struct dma_buf *buffer,
0064         struct vm_area_struct *vma)
0065 {
0066     struct drm_gem_object *obj = buffer->priv;
0067     int ret = 0;
0068
0069     ret = drm_gem_mmap_obj(obj, omap_gem_mmap_size(obj), vma);
0070     if (ret < 0)
0071         return ret;
0072
0073     return omap_gem_mmap_obj(obj, vma);
0074 }
0075
0076 static const struct dma_buf_ops omap_dmabuf_ops = {
0077     .map_dma_buf = omap_gem_map_dma_buf,
0078     .unmap_dma_buf = omap_gem_unmap_dma_buf,
0079     .release = drm_gem_dmabuf_release,
0080     .begin_cpu_access = omap_gem_dmabuf_begin_cpu_access,
0081     .end_cpu_access = omap_gem_dmabuf_end_cpu_access,
0082     .mmap = omap_gem_dmabuf_mmap,
0083 };
0084
0085 struct dma_buf *omap_gem_prime_export(struct drm_gem_object *obj, int flags)
0086 {
0087     DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
0088
0089     exp_info.ops = &omap_dmabuf_ops;
0090     exp_info.size = omap_gem_mmap_size(obj);
0091     exp_info.flags = flags;
0092     exp_info.priv = obj;
0093     exp_info.resv = obj->resv;
0094
0095     return drm_gem_dmabuf_export(obj->dev, &exp_info);
0096 }
0097
0098 /* -----------------------------------------------------------------------------
0099  * DMABUF Import
0100  */
0101
0102 struct drm_gem_object *omap_gem_prime_import(struct drm_device *dev,
0103                          struct dma_buf *dma_buf)
0104 {
0105     struct dma_buf_attachment *attach;
0106     struct drm_gem_object *obj;
0107     struct sg_table *sgt;
0108     int ret;
0109
0110     if (dma_buf->ops == &omap_dmabuf_ops) {
0111         obj = dma_buf->priv;
0112         if (obj->dev == dev) {
0113             /*
0114              * Importing dmabuf exported from out own gem increases
0115              * refcount on gem itself instead of f_count of dmabuf.
0116              */
0117             drm_gem_object_get(obj);
0118             return obj;
0119         }
0120     }
0121
0122     attach = dma_buf_attach(dma_buf, dev->dev);
0123     if (IS_ERR(attach))
0124         return ERR_CAST(attach);
0125
0126     get_dma_buf(dma_buf);
0127
0128     sgt = dma_buf_map_attachment(attach, DMA_TO_DEVICE);
0129     if (IS_ERR(sgt)) {
0130         ret = PTR_ERR(sgt);
0131         goto fail_detach;
0132     }
0133
0134     obj = omap_gem_new_dmabuf(dev, dma_buf->size, sgt);
0135     if (IS_ERR(obj)) {
0136         ret = PTR_ERR(obj);
0137         goto fail_unmap;
0138     }
0139
0140     obj->import_attach = attach;
0141
0142     return obj;
0143
0144 fail_unmap:
0145     dma_buf_unmap_attachment(attach, sgt, DMA_TO_DEVICE);
0146 fail_detach:
0147     dma_buf_detach(dma_buf, attach);
0148     dma_buf_put(dma_buf);
0149
0150     return ERR_PTR(ret);
0151 }