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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (c) 2015 MediaTek Inc.
* Copyright (c) 2025 Collabora Ltd.
* AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
*/
#include <linux/dma-buf.h>
#include <linux/vmalloc.h>
#include <drm/drm.h>
#include <drm/drm_device.h>
#include <drm/drm_gem.h>
#include <drm/drm_gem_dma_helper.h>
#include <drm/drm_prime.h>
#include <drm/drm_print.h>
#include "mtk_drm_drv.h"
#include "mtk_gem.h"
static int mtk_gem_object_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma);
static void mtk_gem_free_object(struct drm_gem_object *obj)
{
struct drm_gem_dma_object *dma_obj = to_drm_gem_dma_obj(obj);
struct mtk_drm_private *priv = obj->dev->dev_private;
if (dma_obj->sgt)
drm_prime_gem_destroy(obj, dma_obj->sgt);
else
dma_free_wc(priv->dma_dev, dma_obj->base.size,
dma_obj->vaddr, dma_obj->dma_addr);
/* release file pointer to gem object. */
drm_gem_object_release(obj);
kfree(dma_obj);
}
/*
* Allocate a sg_table for this GEM object.
* Note: Both the table's contents, and the sg_table itself must be freed by
* the caller.
* Returns a pointer to the newly allocated sg_table, or an ERR_PTR() error.
*/
static struct sg_table *mtk_gem_prime_get_sg_table(struct drm_gem_object *obj)
{
struct drm_gem_dma_object *dma_obj = to_drm_gem_dma_obj(obj);
struct mtk_drm_private *priv = obj->dev->dev_private;
struct sg_table *sgt;
int ret;
sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
if (!sgt)
return ERR_PTR(-ENOMEM);
ret = dma_get_sgtable(priv->dma_dev, sgt, dma_obj->vaddr,
dma_obj->dma_addr, obj->size);
if (ret) {
DRM_ERROR("failed to allocate sgt, %d\n", ret);
kfree(sgt);
return ERR_PTR(ret);
}
return sgt;
}
static const struct drm_gem_object_funcs mtk_gem_object_funcs = {
.free = mtk_gem_free_object,
.print_info = drm_gem_dma_object_print_info,
.get_sg_table = mtk_gem_prime_get_sg_table,
.vmap = drm_gem_dma_object_vmap,
.mmap = mtk_gem_object_mmap,
.vm_ops = &drm_gem_dma_vm_ops,
};
static struct drm_gem_dma_object *mtk_gem_init(struct drm_device *dev,
unsigned long size, bool private)
{
struct drm_gem_dma_object *dma_obj;
int ret;
size = round_up(size, PAGE_SIZE);
if (size == 0)
return ERR_PTR(-EINVAL);
dma_obj = kzalloc(sizeof(*dma_obj), GFP_KERNEL);
if (!dma_obj)
return ERR_PTR(-ENOMEM);
dma_obj->base.funcs = &mtk_gem_object_funcs;
if (private) {
ret = 0;
drm_gem_private_object_init(dev, &dma_obj->base, size);
} else {
ret = drm_gem_object_init(dev, &dma_obj->base, size);
}
if (ret) {
DRM_ERROR("failed to initialize gem object\n");
kfree(dma_obj);
return ERR_PTR(ret);
}
return dma_obj;
}
static struct drm_gem_dma_object *mtk_gem_create(struct drm_device *dev, size_t size)
{
struct mtk_drm_private *priv = dev->dev_private;
struct drm_gem_dma_object *dma_obj;
struct drm_gem_object *obj;
int ret;
dma_obj = mtk_gem_init(dev, size, false);
if (IS_ERR(dma_obj))
return ERR_CAST(dma_obj);
obj = &dma_obj->base;
dma_obj->vaddr = dma_alloc_wc(priv->dma_dev, obj->size,
&dma_obj->dma_addr,
GFP_KERNEL | __GFP_NOWARN);
if (!dma_obj->vaddr) {
DRM_ERROR("failed to allocate %zx byte dma buffer", obj->size);
ret = -ENOMEM;
goto err_gem_free;
}
DRM_DEBUG_DRIVER("vaddr = %p dma_addr = %pad size = %zu\n",
dma_obj->vaddr, &dma_obj->dma_addr,
size);
return dma_obj;
err_gem_free:
drm_gem_object_release(obj);
kfree(dma_obj);
return ERR_PTR(ret);
}
int mtk_gem_dumb_create(struct drm_file *file_priv, struct drm_device *dev,
struct drm_mode_create_dumb *args)
{
struct drm_gem_dma_object *dma_obj;
int ret;
args->pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
/*
* Multiply 2 variables of different types,
* for example: args->size = args->spacing * args->height;
* may cause coverity issue with unintentional overflow.
*/
args->size = args->pitch;
args->size *= args->height;
dma_obj = mtk_gem_create(dev, args->size);
if (IS_ERR(dma_obj))
return PTR_ERR(dma_obj);
/*
* allocate a id of idr table where the obj is registered
* and handle has the id what user can see.
*/
ret = drm_gem_handle_create(file_priv, &dma_obj->base, &args->handle);
if (ret)
goto err_handle_create;
/* drop reference from allocate - handle holds it now. */
drm_gem_object_put(&dma_obj->base);
return 0;
err_handle_create:
mtk_gem_free_object(&dma_obj->base);
return ret;
}
static int mtk_gem_object_mmap(struct drm_gem_object *obj,
struct vm_area_struct *vma)
{
struct drm_gem_dma_object *dma_obj = to_drm_gem_dma_obj(obj);
struct mtk_drm_private *priv = obj->dev->dev_private;
int ret;
/*
* Set vm_pgoff (used as a fake buffer offset by DRM) to 0 and map the
* whole buffer from the start.
*/
vma->vm_pgoff -= drm_vma_node_start(&obj->vma_node);
/*
* dma_alloc_attrs() allocated a struct page table for mtk_gem, so clear
* VM_PFNMAP flag that was set by drm_gem_mmap_obj()/drm_gem_mmap().
*/
vm_flags_mod(vma, VM_IO | VM_DONTEXPAND | VM_DONTDUMP, VM_PFNMAP);
vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);
ret = dma_mmap_wc(priv->dma_dev, vma, dma_obj->vaddr,
dma_obj->dma_addr, obj->size);
if (ret)
drm_gem_vm_close(vma);
return ret;
}
struct drm_gem_object *mtk_gem_prime_import_sg_table(struct drm_device *dev,
struct dma_buf_attachment *attach, struct sg_table *sgt)
{
struct drm_gem_dma_object *dma_obj;
/* check if the entries in the sg_table are contiguous */
if (drm_prime_get_contiguous_size(sgt) < attach->dmabuf->size) {
DRM_ERROR("sg_table is not contiguous");
return ERR_PTR(-EINVAL);
}
dma_obj = mtk_gem_init(dev, attach->dmabuf->size, true);
if (IS_ERR(dma_obj))
return ERR_CAST(dma_obj);
dma_obj->dma_addr = sg_dma_address(sgt->sgl);
dma_obj->sgt = sgt;
return &dma_obj->base;
}
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