/*
* Copyright © 2012 Red Hat
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*
* Authors:
* Dave Airlie <airlied@redhat.com>
* Rob Clark <rob.clark@linaro.org>
*
*/
#include <linux/export.h>
#include <linux/dma-buf.h>
#include <drm/drmP.h>
/*
* DMA-BUF/GEM Object references and lifetime overview:
*
* On the export the dma_buf holds a reference to the exporting GEM
* object. It takes this reference in handle_to_fd_ioctl, when it
* first calls .prime_export and stores the exporting GEM object in
* the dma_buf priv. This reference is released when the dma_buf
* object goes away in the driver .release function.
*
* On the import the importing GEM object holds a reference to the
* dma_buf (which in turn holds a ref to the exporting GEM object).
* It takes that reference in the fd_to_handle ioctl.
* It calls dma_buf_get, creates an attachment to it and stores the
* attachment in the GEM object. When this attachment is destroyed
* when the imported object is destroyed, we remove the attachment
* and drop the reference to the dma_buf.
*
* Thus the chain of references always flows in one direction
* (avoiding loops): importing_gem -> dmabuf -> exporting_gem
*
* Self-importing: if userspace is using PRIME as a replacement for flink
* then it will get a fd->handle request for a GEM object that it created.
* Drivers should detect this situation and return back the gem object
* from the dma-buf private. Prime will do this automatically for drivers that
* use the drm_gem_prime_{import,export} helpers.
*/
struct drm_prime_member {
struct list_head entry;
struct dma_buf *dma_buf;
uint32_t handle;
};
struct drm_prime_attachment {
struct sg_table *sgt;
enum dma_data_direction dir;
};
static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t handle)
{
struct drm_prime_member *member;
member = kmalloc(sizeof(*member), GFP_KERNEL);
if (!member)
return -ENOMEM;
get_dma_buf(dma_buf);
member->dma_buf = dma_buf;
member->handle = handle;
list_add(&member->entry, &prime_fpriv->head);
return 0;
}
static struct dma_buf *drm_prime_lookup_buf_by_handle(struct drm_prime_file_private *prime_fpriv,
uint32_t handle)
{
struct drm_prime_member *member;
list_for_each_entry(member, &prime_fpriv->head, entry) {
if (member->handle == handle)
return member->dma_buf;
}
return NULL;
}
static int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpriv,
struct dma_buf *dma_buf,
uint32_t *handle)
{
struct drm_prime_member *member;
list_for_each_entry(member, &prime_fpriv->head, entry) {
if (member->dma_buf == dma_buf) {
*handle = member->handle;
return 0;
}
}
return -ENOENT;
}
static int drm_gem_map_attach(struct dma_buf *dma_buf,
struct device *target_dev,
struct dma_buf_attachment *attach)
{
struct drm_prime_attachment *prime_attach;
struct drm_gem_object *obj = dma_buf->priv;
struct drm_device *dev = obj->dev;
prime_attach = kzalloc(sizeof(*prime_attach), GFP_KERNEL);
if (!prime_attach)
return -ENOMEM;
prime_attach->dir = DMA_NONE;
attach->priv = prime_attach;
if (!dev->driver->gem_prime_pin)
return 0;
return dev->driver->gem_prime_pin(obj);
}
static void drm_gem_map_detach(struct dma_buf *dma_buf,
struct dma_buf_attachment *attach)
{
struct drm_prime_attachment *prime_attach = attach->priv;
struct drm_gem_object *obj = dma_buf->priv;
struct drm_device *dev = obj->dev;
struct sg_table *sgt;
if (dev->driver->gem_prime_unpin)
dev->driver->gem_prime_unpin(obj);
if (!prime_attach)
return;
sgt = prime_attach->sgt;
if (sgt) {
if (prime_attach->dir != DMA_NONE)
dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents,
prime_attach->dir);
sg_free_table(sgt);
}
kfree(sgt);
kfree(prime_attach);
attach->priv = NULL;
}
void drm_prime_remove_buf_handle_locked(struct drm_prime_file_private *prime_fpriv,
struct dma_buf *dma_buf)
{
struct drm_prime_member *member, *safe;
list_for_each_entry_safe(member, safe, &prime_fpriv->head, entry) {
if (member->dma_buf == dma_buf) {
dma_buf_put(dma_buf);
list_del(&member->entry);
kfree(member);
}
}
}
static struct sg_table *drm_gem_map_dma_buf(struct dma_buf_attachment *attach,
enum dma_data_direction dir)
{
struct drm_prime_attachment *prime_attach = attach->priv;
struct drm_gem_object *obj = attach->dmabuf->priv;
struct sg_table *sgt;
if (WARN_ON(dir == DMA_NONE || !prime_attach))
return ERR_PTR(-EINVAL);
/* return the cached mapping when possible */
if (prime_attach->dir == dir)
return prime_attach->sgt;
/*
* two mappings with different directions for the same attachment are
* not allowed
*/
if (WARN_ON(prime_attach->dir != DMA_NONE))
return ERR_PTR(-EBUSY);
sgt = obj->dev->driver->gem_prime_get_sg_table(obj);
if (!IS_ERR(sgt)) {
if (!dma_map_sg(attach->dev, sgt->sgl, sgt->nents, dir)) {
sg_free_table(sgt);
kfree(sgt);
sgt = ERR_PTR(-ENOMEM);
} else {
prime_attach->sgt = sgt;
prime_attach->dir = dir;
}
}
return sgt;
}
static void drm_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
struct sg_table *sgt, enum dma_data_direction dir)
{
/* nothing to be done here */
}
void drm_gem_dmabuf_release(struct dma_buf *dma_buf)
{
struct drm_gem_object *obj = dma_buf->priv;
/* drop the reference on the export fd holds */
drm_gem_object_unreference_unlocked(obj);
}
EXPORT_SYMBOL(drm_gem_dmabuf_release);
static void *drm_gem_dmabuf_vmap(struct dma_buf *dma_buf)
{
struct drm_gem_object *obj = dma_buf->priv;
struct drm_device *dev = obj->dev;
return dev->driver->gem_prime_vmap(obj);
}
static void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, void *vaddr)
{
struct drm_gem_object *obj = dma_buf->priv;
struct drm_device *dev = obj->dev;
dev->driver->gem_prime_vunmap(obj, vaddr);
}
static void *drm_gem_dmabuf_kmap_atomic(struct dma_buf *dma_buf,
unsigned long page_num)
{
return NULL;
}
static void drm_gem_dmabuf_kunmap_atomic(struct dma_buf *dma_buf,
unsigned long page_num, void *addr)
{
}
static void *drm_gem_dmabuf_kmap(struct dma_buf *dma_buf,
unsigned long page_num)
{
return NULL;
}
static void drm_gem_dmabuf_kunmap(struct dma_buf *dma_buf,
unsigned long page_num, void *addr)
{
}
static int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf,
struct vm_area_struct *vma)
{
struct drm_gem_object *obj = dma_buf->priv;
struct drm_device *dev = obj->dev;
if (!dev->driver->gem_prime_mmap)
return -ENOSYS;
return dev->driver->gem_prime_mmap(obj, vma);
}
static const struct dma_buf_ops drm_gem_prime_dmabuf_ops = {
.attach = drm_gem_map_attach,
.detach = drm_gem_map_detach,
.map_dma_buf = drm_gem_map_dma_buf,
.unmap_dma_buf = drm_gem_unmap_dma_buf,
.release = drm_gem_dmabuf_release,
.kmap = drm_gem_dmabuf_kmap,
.kmap_atomic = drm_gem_dmabuf_kmap_atomic,
.kunmap = drm_gem_dmabuf_kunmap,
.kunmap_atomic = drm_gem_dmabuf_kunmap_atomic,
.mmap = drm_gem_dmabuf_mmap,
.vmap = drm_gem_dmabuf_vmap,
.vunmap = drm_gem_dmabuf_vunmap,
};
/**
* DOC: PRIME Helpers
*
* Drivers can implement @gem_prime_export and @gem_prime_import in terms of
* simpler APIs by using the helper functions @drm_gem_prime_export and
* @drm_gem_prime_import. These functions implement dma-buf support in terms of
* five lower-level driver callbacks:
*
* Export callbacks:
*
* - @gem_prime_pin (optional): prepare a GEM object for exporting
*
* - @gem_prime_get_sg_table: provide a scatter/gather table of pinned pages
*
* - @gem_prime_vmap: vmap a buffer exported by your driver
*
* - @gem_prime_vunmap: vunmap a buffer exported by your driver
*
* Import callback:
*
* - @gem_prime_import_sg_table (import): produce a GEM object from another
* driver's scatter/gather table
*/
struct dma_buf *drm_gem_prime_export(struct drm_device *dev,
struct drm_gem_object *obj, int flags)
{
return dma_buf_export(obj, &drm_gem_prime_dmabuf_ops, obj->size, flags);
}
EXPORT_SYMBOL(drm_gem_prime_export);
static struct dma_buf *export_and_register_object(struct drm_device *dev,
struct drm_gem_object *obj,
uint32_t flags)
{
struct dma_buf *dmabuf;
/* prevent races with concurrent gem_close. */
if (obj->handle_count == 0) {
dmabuf = ERR_PTR(-ENOENT);
return dmabuf;
}
dmabuf = dev->driver->gem_prime_export(dev, obj, flags);
if (IS_ERR(dmabuf)) {
/* normally the created dma-buf takes ownership of the ref,
* but if that fails then drop the ref
*/
return dmabuf;
}
/*
* Note that callers do not need to clean up the export cache
* since the check for obj->handle_count guarantees that someone
* will clean it up.
*/
obj->dma_buf = dmabuf;
get_dma_buf(obj->dma_buf);
/* Grab a new ref since the callers is now used by the dma-buf */
drm_gem_object_reference(obj);
return dmabuf;
}
int drm_gem_prime_handle_to_fd(struct drm_device *dev,
struct drm_file *file_priv, uint32_t handle, uint32_t flags,
int *prime_fd)
{
struct drm_gem_object *obj;
int ret = 0;
struct dma_buf *dmabuf;
mutex_lock(&file_priv->prime.lock);
obj = drm_gem_object_lookup(dev, file_priv, handle);
if (!obj) {
ret = -ENOENT;
goto out_unlock;
}
dmabuf = drm_prime_lookup_buf_by_handle(&file_priv->prime, handle);
if (dmabuf) {
get_dma_buf(dmabuf);
goto out_have_handle;
}
mutex_lock(&dev->object_name_lock);
/* re-export the original imported object */
if (obj->import_attach) {
dmabuf = obj->import_attach->dmabuf;
get_dma_buf(dmabuf);
goto out_have_obj;
}
if (obj->dma_buf) {
get_dma_buf(obj->dma_buf);
dmabuf = obj->dma_buf;
goto out_have_obj;
}
dmabuf = export_and_register_object(dev, obj, flags);
if (IS_ERR(dmabuf)) {
/* normally the created dma-buf takes ownership of the ref,
* but if that fails then drop the ref
*/
ret = PTR_ERR(dmabuf);
mutex_unlock(&dev->object_name_lock);
goto out;
}
out_have_obj:
/*
* If we've exported this buffer then cheat and add it to the import list
* so we get the correct handle back. We must do this under the
* protection of dev->object_name_lock to ensure that a racing gem close
* ioctl doesn't miss to remove this buffer handle from the cache.
*/
ret = drm_prime_add_buf_handle(&file_priv->prime,
dmabuf, handle);
mutex_unlock(&dev->object_name_lock);
if (ret)
goto fail_put_dmabuf;
out_have_handle:
ret = dma_buf_fd(dmabuf, flags);
/*
* We must _not_ remove the buffer from the handle cache since the newly
* created dma buf is already linked in the global obj->dma_buf pointer,
* and that is invariant as long as a userspace gem handle exists.
* Closing the handle will clean out the cache anyway, so we don't leak.
*/
if (ret < 0) {
goto fail_put_dmabuf;
} else {
*prime_fd = ret;
ret = 0;
}
goto out;
fail_put_dmabuf:
dma_buf_put(dmabuf);
out:
drm_gem_object_unreference_unlocked(obj);
out_unlock:
mutex_unlock(&file_priv->prime.lock);
return ret;
}
EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
struct dma_buf *dma_buf)
{
struct dma_buf_attachment *attach;
struct sg_table *sgt;
struct drm_gem_object *obj;
int ret;
if (!dev->driver->gem_prime_import_sg_table)
return ERR_PTR(-EINVAL);
if (dma_buf->ops == &drm_gem_prime_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_reference(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(attach, DMA_BIDIRECTIONAL);
if (IS_ERR_OR_NULL(sgt)) {
ret = PTR_ERR(sgt);
goto fail_detach;
}
obj = dev->driver->gem_prime_import_sg_table(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(attach, sgt, DMA_BIDIRECTIONAL);
fail_detach:
dma_buf_detach(dma_buf, attach);
dma_buf_put(dma_buf);
return ERR_PTR(ret);
}
EXPORT_SYMBOL(drm_gem_prime_import);
int drm_gem_prime_fd_to_handle(struct drm_device *dev,
struct drm_file *file_priv, int prime_fd, uint32_t *handle)
{
struct dma_buf *dma_buf;
struct drm_gem_object *obj;
int ret;
dma_buf = dma_buf_get(prime_fd);
if (IS_ERR(dma_buf))
return PTR_ERR(dma_buf);
mutex_lock(&file_priv->prime.lock);
ret = drm_prime_lookup_buf_handle(&file_priv->prime,
dma_buf, handle);
if (ret == 0)
goto out_put;
/* never seen this one, need to import */
mutex_lock(&dev->object_name_lock);
obj = dev->driver->gem_prime_import(dev, dma_buf);
if (IS_ERR(obj)) {
ret = PTR_ERR(obj);
goto out_unlock;
}
if (obj->dma_buf) {
WARN_ON(obj->dma_buf != dma_buf);
} else {
obj->dma_buf = dma_buf;
get_dma_buf(dma_buf);
}
/* drm_gem_handle_create_tail unlocks dev->object_name_lock. */
ret = drm_gem_handle_create_tail(file_priv, obj, handle);
drm_gem_object_unreference_unlocked(obj);
if (ret)
goto out_put;
ret = drm_prime_add_buf_handle(&file_priv->prime,
dma_buf, *handle);
if (ret)
goto fail;
mutex_unlock(&file_priv->prime.lock);
dma_buf_put(dma_buf);
return 0;
fail:
/* hmm, if driver attached, we are relying on the free-object path
* to detach.. which seems ok..
*/
drm_gem_handle_delete(file_priv, *handle);
out_unlock:
mutex_unlock(&dev->object_name_lock);
out_put:
dma_buf_put(dma_buf);
mutex_unlock(&file_priv->prime.lock);
return ret;
}
EXPORT_SYMBOL(drm_gem_prime_fd_to_handle);
int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
struct drm_file *file_priv)
{
struct drm_prime_handle *args = data;
uint32_t flags;
if (!drm_core_check_feature(dev, DRIVER_PRIME))
return -EINVAL;
if (!dev->driver->prime_handle_to_fd)
return -ENOSYS;
/* check flags are valid */
if (args->flags & ~DRM_CLOEXEC)
return -EINVAL;
/* we only want to pass DRM_CLOEXEC which is == O_CLOEXEC */
flags = args->flags & DRM_CLOEXEC;
return dev->driver->prime_handle_to_fd(dev, file_priv,
args->handle, flags, &args->fd);
}
int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
struct drm_file *file_priv)
{
struct drm_prime_handle *args = data;
if (!drm_core_check_feature(dev, DRIVER_PRIME))
return -EINVAL;
if (!dev->driver->prime_fd_to_handle)
return -ENOSYS;
return dev->driver->prime_fd_to_handle(dev, file_priv,
args->fd, &args->handle);
}
/*
* drm_prime_pages_to_sg
*
* this helper creates an sg table object from a set of pages
* the driver is responsible for mapping the pages into the
* importers address space
*/
struct sg_table *drm_prime_pages_to_sg(struct page **pages, int nr_pages)
{
struct sg_table *sg = NULL;
int ret;
sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
if (!sg) {
ret = -ENOMEM;
goto out;
}
ret = sg_alloc_table_from_pages(sg, pages, nr_pages, 0,
nr_pages << PAGE_SHIFT, GFP_KERNEL);
if (ret)
goto out;
return sg;
out:
kfree(sg);
return ERR_PTR(ret);
}
EXPORT_SYMBOL(drm_prime_pages_to_sg);
/* export an sg table into an array of pages and addresses
this is currently required by the TTM driver in order to do correct fault
handling */
int drm_prime_sg_to_page_addr_arrays(struct sg_table *sgt, struct page **pages,
dma_addr_t *addrs, int max_pages)
{
unsigned count;
struct scatterlist *sg;
struct page *page;
u32 len, offset;
int pg_index;
dma_addr_t addr;
pg_index = 0;
for_each_sg(sgt->sgl, sg, sgt->nents, count) {
len = sg->length;
offset = sg->offset;
page = sg_page(sg);
addr = sg_dma_address(sg);
while (len > 0) {
if (WARN_ON(pg_index >= max_pages))
return -1;
pages[pg_index] = page;
if (addrs)
addrs[pg_index] = addr;
page++;
addr += PAGE_SIZE;
len -= PAGE_SIZE;
pg_index++;
}
}
return 0;
}
EXPORT_SYMBOL(drm_prime_sg_to_page_addr_arrays);
/* helper function to cleanup a GEM/prime object */
void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg)
{
struct dma_buf_attachment *attach;
struct dma_buf *dma_buf;
attach = obj->import_attach;
if (sg)
dma_buf_unmap_attachment(attach, sg, DMA_BIDIRECTIONAL);
dma_buf = attach->dmabuf;
dma_buf_detach(attach->dmabuf, attach);
/* remove the reference */
dma_buf_put(dma_buf);
}
EXPORT_SYMBOL(drm_prime_gem_destroy);
void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv)
{
INIT_LIST_HEAD(&prime_fpriv->head);
mutex_init(&prime_fpriv->lock);
}
EXPORT_SYMBOL(drm_prime_init_file_private);
void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv)
{
/* by now drm_gem_release should've made sure the list is empty */
WARN_ON(!list_empty(&prime_fpriv->head));
}
EXPORT_SYMBOL(drm_prime_destroy_file_private);
