Commit eaee1c08 authored by Nirmoy Das's avatar Nirmoy Das
Browse files

drm/i915: Add a function to mmap framebuffer obj 



Implement i915_gem_fb_mmap() to enable fb_ops.fb_mmap()
callback for i915's framebuffer objects.

v2: add a comment why i915_gem_object_get() needed(Andi).
v3: mmap also ttm objects.

Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Andi Shyti <andi.shyti@linux.intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Signed-off-by: default avatarNirmoy Das <nirmoy.das@intel.com>
Reviewed-by: default avatarAndi Shyti <andi.shyti@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230404143100.10452-3-nirmoy.das@intel.com
parent ddb78a51

drivers/gpu/drm/i915/gem/i915_gem_mman.c

+92 −45
Original line number Diff line number Diff line
@@ -927,53 +927,15 @@ static struct file *mmap_singleton(struct drm_i915_private *i915) 
	return file;

}



/*

 * This overcomes the limitation in drm_gem_mmap's assignment of a

 * drm_gem_object as the vma->vm_private_data. Since we need to

 * be able to resolve multiple mmap offsets which could be tied

 * to a single gem object.

 */

int i915_gem_mmap(struct file *filp, struct vm_area_struct *vma)

static int

i915_gem_object_mmap(struct drm_i915_gem_object *obj,

		     struct i915_mmap_offset *mmo,

		     struct vm_area_struct *vma)

{

	struct drm_vma_offset_node *node;

	struct drm_file *priv = filp->private_data;

	struct drm_device *dev = priv->minor->dev;

	struct drm_i915_gem_object *obj = NULL;

	struct i915_mmap_offset *mmo = NULL;

	struct drm_i915_private *i915 = to_i915(obj->base.dev);

	struct drm_device *dev = &i915->drm;

	struct file *anon;



	if (drm_dev_is_unplugged(dev))

		return -ENODEV;



	rcu_read_lock();

	drm_vma_offset_lock_lookup(dev->vma_offset_manager);

	node = drm_vma_offset_exact_lookup_locked(dev->vma_offset_manager,

						  vma->vm_pgoff,

						  vma_pages(vma));

	if (node && drm_vma_node_is_allowed(node, priv)) {

		/*

		 * Skip 0-refcnted objects as it is in the process of being

		 * destroyed and will be invalid when the vma manager lock

		 * is released.

		 */

		if (!node->driver_private) {

			mmo = container_of(node, struct i915_mmap_offset, vma_node);

			obj = i915_gem_object_get_rcu(mmo->obj);



			GEM_BUG_ON(obj && obj->ops->mmap_ops);

		} else {

			obj = i915_gem_object_get_rcu

				(container_of(node, struct drm_i915_gem_object,

					      base.vma_node));



			GEM_BUG_ON(obj && !obj->ops->mmap_ops);

		}

	}

	drm_vma_offset_unlock_lookup(dev->vma_offset_manager);

	rcu_read_unlock();

	if (!obj)

		return node ? -EACCES : -EINVAL;



	if (i915_gem_object_is_readonly(obj)) {

		if (vma->vm_flags & VM_WRITE) {

			i915_gem_object_put(obj);
@@ -1005,7 +967,7 @@ int i915_gem_mmap(struct file *filp, struct vm_area_struct *vma) 
	if (obj->ops->mmap_ops) {

		vma->vm_page_prot = pgprot_decrypted(vm_get_page_prot(vma->vm_flags));

		vma->vm_ops = obj->ops->mmap_ops;

		vma->vm_private_data = node->driver_private;

		vma->vm_private_data = obj->base.vma_node.driver_private;

		return 0;

	}
@@ -1043,6 +1005,91 @@ int i915_gem_mmap(struct file *filp, struct vm_area_struct *vma) 
	return 0;

}



/*

 * This overcomes the limitation in drm_gem_mmap's assignment of a

 * drm_gem_object as the vma->vm_private_data. Since we need to

 * be able to resolve multiple mmap offsets which could be tied

 * to a single gem object.

 */

int i915_gem_mmap(struct file *filp, struct vm_area_struct *vma)

{

	struct drm_vma_offset_node *node;

	struct drm_file *priv = filp->private_data;

	struct drm_device *dev = priv->minor->dev;

	struct drm_i915_gem_object *obj = NULL;

	struct i915_mmap_offset *mmo = NULL;



	if (drm_dev_is_unplugged(dev))

		return -ENODEV;



	rcu_read_lock();

	drm_vma_offset_lock_lookup(dev->vma_offset_manager);

	node = drm_vma_offset_exact_lookup_locked(dev->vma_offset_manager,

						  vma->vm_pgoff,

						  vma_pages(vma));

	if (node && drm_vma_node_is_allowed(node, priv)) {

		/*

		 * Skip 0-refcnted objects as it is in the process of being

		 * destroyed and will be invalid when the vma manager lock

		 * is released.

		 */

		if (!node->driver_private) {

			mmo = container_of(node, struct i915_mmap_offset, vma_node);

			obj = i915_gem_object_get_rcu(mmo->obj);



			GEM_BUG_ON(obj && obj->ops->mmap_ops);

		} else {

			obj = i915_gem_object_get_rcu

				(container_of(node, struct drm_i915_gem_object,

					      base.vma_node));



			GEM_BUG_ON(obj && !obj->ops->mmap_ops);

		}

	}

	drm_vma_offset_unlock_lookup(dev->vma_offset_manager);

	rcu_read_unlock();

	if (!obj)

		return node ? -EACCES : -EINVAL;



	return i915_gem_object_mmap(obj, mmo, vma);

}



int i915_gem_fb_mmap(struct drm_i915_gem_object *obj, struct vm_area_struct *vma)

{

	struct drm_i915_private *i915 = to_i915(obj->base.dev);

	struct drm_device *dev = &i915->drm;

	struct i915_mmap_offset *mmo = NULL;

	enum i915_mmap_type mmap_type;

	struct i915_ggtt *ggtt = to_gt(i915)->ggtt;



	if (drm_dev_is_unplugged(dev))

		return -ENODEV;



	/* handle ttm object */

	if (obj->ops->mmap_ops) {

		/*

		 * ttm fault handler, ttm_bo_vm_fault_reserved() uses fake offset

		 * to calculate page offset so set that up.

		 */

		vma->vm_pgoff += drm_vma_node_start(&obj->base.vma_node);

	} else {

		/* handle stolen and smem objects */

		mmap_type = i915_ggtt_has_aperture(ggtt) ? I915_MMAP_TYPE_GTT : I915_MMAP_TYPE_WC;

		mmo = mmap_offset_attach(obj, mmap_type, NULL);

		if (!mmo)

			return -ENODEV;

	}



	/*

	 * When we install vm_ops for mmap we are too late for

	 * the vm_ops->open() which increases the ref_count of

	 * this obj and then it gets decreased by the vm_ops->close().

	 * To balance this increase the obj ref_count here.

	 */

	obj = i915_gem_object_get(obj);

	return i915_gem_object_mmap(obj, mmo, vma);

}



#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)

#include "selftests/i915_gem_mman.c"

#endif

drivers/gpu/drm/i915/gem/i915_gem_mman.h

+1 −1
Original line number Diff line number Diff line
@@ -29,5 +29,5 @@ void i915_gem_object_release_mmap_gtt(struct drm_i915_gem_object *obj); 


void i915_gem_object_runtime_pm_release_mmap_offset(struct drm_i915_gem_object *obj);

void i915_gem_object_release_mmap_offset(struct drm_i915_gem_object *obj);



int i915_gem_fb_mmap(struct drm_i915_gem_object *obj, struct vm_area_struct *vma);

#endif