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drm: GEM mmap support

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Add core support for mapping of GEM objects.  Drivers should provide a
vm_operations_struct if they want to support page faulting of objects.
The code for handling GEM object offsets was taken from TTM, which was
written by Thomas Hellström.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>
This commit is contained in:
Jesse Barnes
2008-11-05 10:31:53 -08:00
committed by Dave Airlie
parent a9587470f7
commit a2c0a97b78
8 changed files with 161 additions and 3 deletions
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109
drivers/gpu/drm/drm_gem.c
View File

@@ -64,6 +64,13 @@
* up at a later date, and as our interface with shmfs for memory allocation.
*/
/*
* We make up offsets for buffer objects so we can recognize them at
* mmap time.
*/
#define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFFUL >> PAGE_SHIFT) + 1)
#define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFFUL >> PAGE_SHIFT) * 16)
/**
* Initialize the GEM device fields
*/
@@ -71,6 +78,8 @@
int
drm_gem_init(struct drm_device *dev)
{
struct drm_gem_mm *mm;
spin_lock_init(&dev->object_name_lock);
idr_init(&dev->object_name_idr);
atomic_set(&dev->object_count, 0);
@@ -79,9 +88,41 @@ drm_gem_init(struct drm_device *dev)
atomic_set(&dev->pin_memory, 0);
atomic_set(&dev->gtt_count, 0);
atomic_set(&dev->gtt_memory, 0);
mm = drm_calloc(1, sizeof(struct drm_gem_mm), DRM_MEM_MM);
if (!mm) {
DRM_ERROR("out of memory\n");
return -ENOMEM;
}
dev->mm_private = mm;
if (drm_ht_create(&mm->offset_hash, 19)) {
drm_free(mm, sizeof(struct drm_gem_mm), DRM_MEM_MM);
return -ENOMEM;
}
if (drm_mm_init(&mm->offset_manager, DRM_FILE_PAGE_OFFSET_START,
DRM_FILE_PAGE_OFFSET_SIZE)) {
drm_free(mm, sizeof(struct drm_gem_mm), DRM_MEM_MM);
drm_ht_remove(&mm->offset_hash);
return -ENOMEM;
}
return 0;
}
void
drm_gem_destroy(struct drm_device *dev)
{
struct drm_gem_mm *mm = dev->mm_private;
drm_mm_takedown(&mm->offset_manager);
drm_ht_remove(&mm->offset_hash);
drm_free(mm, sizeof(struct drm_gem_mm), DRM_MEM_MM);
dev->mm_private = NULL;
}
/**
* Allocate a GEM object of the specified size with shmfs backing store
*/
@@ -419,3 +460,71 @@ drm_gem_object_handle_free(struct kref *kref)
}
EXPORT_SYMBOL(drm_gem_object_handle_free);
/**
* drm_gem_mmap - memory map routine for GEM objects
* @filp: DRM file pointer
* @vma: VMA for the area to be mapped
*
* If a driver supports GEM object mapping, mmap calls on the DRM file
* descriptor will end up here.
*
* If we find the object based on the offset passed in (vma->vm_pgoff will
* contain the fake offset we created when the GTT map ioctl was called on
* the object), we set up the driver fault handler so that any accesses
* to the object can be trapped, to perform migration, GTT binding, surface
* register allocation, or performance monitoring.
*/
int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
{
struct drm_file *priv = filp->private_data;
struct drm_device *dev = priv->minor->dev;
struct drm_gem_mm *mm = dev->mm_private;
struct drm_map *map = NULL;
struct drm_gem_object *obj;
struct drm_hash_item *hash;
unsigned long prot;
int ret = 0;
mutex_lock(&dev->struct_mutex);
if (drm_ht_find_item(&mm->offset_hash, vma->vm_pgoff, &hash)) {
mutex_unlock(&dev->struct_mutex);
return drm_mmap(filp, vma);
}
map = drm_hash_entry(hash, struct drm_map_list, hash)->map;
if (!map ||
((map->flags & _DRM_RESTRICTED) && !capable(CAP_SYS_ADMIN))) {
ret = -EPERM;
goto out_unlock;
}
/* Check for valid size. */
if (map->size < vma->vm_end - vma->vm_start) {
ret = -EINVAL;
goto out_unlock;
}
obj = map->handle;
if (!obj->dev->driver->gem_vm_ops) {
ret = -EINVAL;
goto out_unlock;
}
vma->vm_flags |= VM_RESERVED | VM_IO | VM_PFNMAP | VM_DONTEXPAND;
vma->vm_ops = obj->dev->driver->gem_vm_ops;
vma->vm_private_data = map->handle;
/* FIXME: use pgprot_writecombine when available */
prot = pgprot_val(vma->vm_page_prot);
prot |= _PAGE_CACHE_WC;
vma->vm_page_prot = __pgprot(prot);
vma->vm_file = filp; /* Needed for drm_vm_open() */
drm_vm_open_locked(vma);
out_unlock:
mutex_unlock(&dev->struct_mutex);
return ret;
}
EXPORT_SYMBOL(drm_gem_mmap);