drm: Add GEM ("graphics execution manager") to i915 driver.

GEM allows the creation of persistent buffer objects accessible by the
graphics device through new ioctls for managing execution of commands on the
device.  The userland API is almost entirely driver-specific to ensure that
any driver building on this model can easily map the interface to individual
driver requirements.

GEM is used by the 2d driver for managing its internal state allocations and
will be used for pixmap storage to reduce memory consumption and enable
zero-copy GLX_EXT_texture_from_pixmap, and in the 3d driver is used to enable
GL_EXT_framebuffer_object and GL_ARB_pixel_buffer_object.

Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>

3 files changed, 514 insertions, 0 deletions

diff --git a/include/drm/drm.h b/include/drm/drm.h
index 15e5503..f46ba4b 100644
--- a/include/drm/drm.h
+++ b/include/drm/drm.h
@@ -570,6 +570,34 @@ struct drm_set_version {
 	int drm_dd_minor;
 };
 
+/** DRM_IOCTL_GEM_CLOSE ioctl argument type */
+struct drm_gem_close {
+	/** Handle of the object to be closed. */
+	uint32_t handle;
+	uint32_t pad;
+};
+
+/** DRM_IOCTL_GEM_FLINK ioctl argument type */
+struct drm_gem_flink {
+	/** Handle for the object being named */
+	uint32_t handle;
+
+	/** Returned global name */
+	uint32_t name;
+};
+
+/** DRM_IOCTL_GEM_OPEN ioctl argument type */
+struct drm_gem_open {
+	/** Name of object being opened */
+	uint32_t name;
+
+	/** Returned handle for the object */
+	uint32_t handle;
+
+	/** Returned size of the object */
+	uint64_t size;
+};
+
 #define DRM_IOCTL_BASE			'd'
 #define DRM_IO(nr)			_IO(DRM_IOCTL_BASE,nr)
 #define DRM_IOR(nr,type)		_IOR(DRM_IOCTL_BASE,nr,type)
@@ -585,6 +613,9 @@ struct drm_set_version {
 #define DRM_IOCTL_GET_STATS             DRM_IOR( 0x06, struct drm_stats)
 #define DRM_IOCTL_SET_VERSION		DRM_IOWR(0x07, struct drm_set_version)
 #define DRM_IOCTL_MODESET_CTL           DRM_IOW(0x08, struct drm_modeset_ctl)
+#define DRM_IOCTL_GEM_CLOSE		DRM_IOW (0x09, struct drm_gem_close)
+#define DRM_IOCTL_GEM_FLINK		DRM_IOWR(0x0a, struct drm_gem_flink)
+#define DRM_IOCTL_GEM_OPEN		DRM_IOWR(0x0b, struct drm_gem_open)
 
 #define DRM_IOCTL_SET_UNIQUE		DRM_IOW( 0x10, struct drm_unique)
 #define DRM_IOCTL_AUTH_MAGIC		DRM_IOW( 0x11, struct drm_auth)
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index e79ce07..1469a1b 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -104,6 +104,7 @@ struct drm_device;
 #define DRIVER_DMA_QUEUE   0x200
 #define DRIVER_FB_DMA      0x400
 #define DRIVER_IRQ_VBL2    0x800
+#define DRIVER_GEM         0x1000
 
 /***********************************************************************/
 /** \name Begin the DRM... */
@@ -387,6 +388,10 @@ struct drm_file {
 	struct drm_minor *minor;
 	int remove_auth_on_close;
 	unsigned long lock_count;
+	/** Mapping of mm object handles to object pointers. */
+	struct idr object_idr;
+	/** Lock for synchronization of access to object_idr. */
+	spinlock_t table_lock;
 	struct file *filp;
 	void *driver_priv;
 };
@@ -558,6 +563,56 @@ struct drm_ati_pcigart_info {
 };
 
 /**
+ * This structure defines the drm_mm memory object, which will be used by the
+ * DRM for its buffer objects.
+ */
+struct drm_gem_object {
+	/** Reference count of this object */
+	struct kref refcount;
+
+	/** Handle count of this object. Each handle also holds a reference */
+	struct kref handlecount;
+
+	/** Related drm device */
+	struct drm_device *dev;
+
+	/** File representing the shmem storage */
+	struct file *filp;
+
+	/**
+	 * Size of the object, in bytes.  Immutable over the object's
+	 * lifetime.
+	 */
+	size_t size;
+
+	/**
+	 * Global name for this object, starts at 1. 0 means unnamed.
+	 * Access is covered by the object_name_lock in the related drm_device
+	 */
+	int name;
+
+	/**
+	 * Memory domains. These monitor which caches contain read/write data
+	 * related to the object. When transitioning from one set of domains
+	 * to another, the driver is called to ensure that caches are suitably
+	 * flushed and invalidated
+	 */
+	uint32_t read_domains;
+	uint32_t write_domain;
+
+	/**
+	 * While validating an exec operation, the
+	 * new read/write domain values are computed here.
+	 * They will be transferred to the above values
+	 * at the point that any cache flushing occurs
+	 */
+	uint32_t pending_read_domains;
+	uint32_t pending_write_domain;
+
+	void *driver_private;
+};
+
+/**
  * DRM driver structure. This structure represent the common code for
  * a family of cards. There will one drm_device for each card present
  * in this family
@@ -657,6 +712,18 @@ struct drm_driver {
 	void (*set_version) (struct drm_device *dev,
 			     struct drm_set_version *sv);
 
+	int (*proc_init)(struct drm_minor *minor);
+	void (*proc_cleanup)(struct drm_minor *minor);
+
+	/**
+	 * Driver-specific constructor for drm_gem_objects, to set up
+	 * obj->driver_private.
+	 *
+	 * Returns 0 on success.
+	 */
+	int (*gem_init_object) (struct drm_gem_object *obj);
+	void (*gem_free_object) (struct drm_gem_object *obj);
+
 	int major;
 	int minor;
 	int patchlevel;
@@ -830,6 +897,22 @@ struct drm_device {
 	spinlock_t drw_lock;
 	struct idr drw_idr;
 	/*@} */
+
+	/** \name GEM information */
+	/*@{ */
+	spinlock_t object_name_lock;
+	struct idr object_name_idr;
+	atomic_t object_count;
+	atomic_t object_memory;
+	atomic_t pin_count;
+	atomic_t pin_memory;
+	atomic_t gtt_count;
+	atomic_t gtt_memory;
+	uint32_t gtt_total;
+	uint32_t invalidate_domains;    /* domains pending invalidation */
+	uint32_t flush_domains;         /* domains pending flush */
+	/*@} */
+
 };
 
 static __inline__ int drm_core_check_feature(struct drm_device *dev,
@@ -926,6 +1009,10 @@ extern void *drm_realloc(void *oldpt, size_t oldsize, size_t size, int area);
 extern DRM_AGP_MEM *drm_alloc_agp(struct drm_device *dev, int pages, u32 type);
 extern int drm_free_agp(DRM_AGP_MEM * handle, int pages);
 extern int drm_bind_agp(DRM_AGP_MEM * handle, unsigned int start);
+extern DRM_AGP_MEM *drm_agp_bind_pages(struct drm_device *dev,
+				       struct page **pages,
+				       unsigned long num_pages,
+				       uint32_t gtt_offset);
 extern int drm_unbind_agp(DRM_AGP_MEM * handle);
 
 				/* Misc. IOCTL support (drm_ioctl.h) */
@@ -988,6 +1075,9 @@ extern int drm_getmagic(struct drm_device *dev, void *data,
 extern int drm_authmagic(struct drm_device *dev, void *data,
 			 struct drm_file *file_priv);
 
+/* Cache management (drm_cache.c) */
+void drm_clflush_pages(struct page *pages[], unsigned long num_pages);
+
 				/* Locking IOCTL support (drm_lock.h) */
 extern int drm_lock(struct drm_device *dev, void *data,
 		    struct drm_file *file_priv);
@@ -1094,6 +1184,7 @@ extern DRM_AGP_MEM *drm_agp_allocate_memory(struct agp_bridge_data *bridge, size
 extern int drm_agp_free_memory(DRM_AGP_MEM * handle);
 extern int drm_agp_bind_memory(DRM_AGP_MEM * handle, off_t start);
 extern int drm_agp_unbind_memory(DRM_AGP_MEM * handle);
+extern void drm_agp_chipset_flush(struct drm_device *dev);
 
 				/* Stub support (drm_stub.h) */
 extern int drm_get_dev(struct pci_dev *pdev, const struct pci_device_id *ent,
@@ -1156,6 +1247,66 @@ extern unsigned long drm_mm_tail_space(struct drm_mm *mm);
 extern int drm_mm_remove_space_from_tail(struct drm_mm *mm, unsigned long size);
 extern int drm_mm_add_space_to_tail(struct drm_mm *mm, unsigned long size);
 
+/* Graphics Execution Manager library functions (drm_gem.c) */
+int drm_gem_init(struct drm_device *dev);
+void drm_gem_object_free(struct kref *kref);
+struct drm_gem_object *drm_gem_object_alloc(struct drm_device *dev,
+					    size_t size);
+void drm_gem_object_handle_free(struct kref *kref);
+
+static inline void
+drm_gem_object_reference(struct drm_gem_object *obj)
+{
+	kref_get(&obj->refcount);
+}
+
+static inline void
+drm_gem_object_unreference(struct drm_gem_object *obj)
+{
+	if (obj == NULL)
+		return;
+
+	kref_put(&obj->refcount, drm_gem_object_free);
+}
+
+int drm_gem_handle_create(struct drm_file *file_priv,
+			  struct drm_gem_object *obj,
+			  int *handlep);
+
+static inline void
+drm_gem_object_handle_reference(struct drm_gem_object *obj)
+{
+	drm_gem_object_reference(obj);
+	kref_get(&obj->handlecount);
+}
+
+static inline void
+drm_gem_object_handle_unreference(struct drm_gem_object *obj)
+{
+	if (obj == NULL)
+		return;
+
+	/*
+	 * Must bump handle count first as this may be the last
+	 * ref, in which case the object would disappear before we
+	 * checked for a name
+	 */
+	kref_put(&obj->handlecount, drm_gem_object_handle_free);
+	drm_gem_object_unreference(obj);
+}
+
+struct drm_gem_object *drm_gem_object_lookup(struct drm_device *dev,
+					     struct drm_file *filp,
+					     int handle);
+int drm_gem_close_ioctl(struct drm_device *dev, void *data,
+			struct drm_file *file_priv);
+int drm_gem_flink_ioctl(struct drm_device *dev, void *data,
+			struct drm_file *file_priv);
+int drm_gem_open_ioctl(struct drm_device *dev, void *data,
+		       struct drm_file *file_priv);
+void drm_gem_open(struct drm_device *dev, struct drm_file *file_private);
+void drm_gem_release(struct drm_device *dev, struct drm_file *file_private);
+
 extern void drm_core_ioremap(struct drm_map *map, struct drm_device *dev);
 extern void drm_core_ioremap_wc(struct drm_map *map, struct drm_device *dev);
 extern void drm_core_ioremapfree(struct drm_map *map, struct drm_device *dev);
diff --git a/include/drm/i915_drm.h b/include/drm/i915_drm.h
index 05c66cf..59d08fc 100644
--- a/include/drm/i915_drm.h
+++ b/include/drm/i915_drm.h
@@ -143,6 +143,22 @@ typedef struct _drm_i915_sarea {
 #define DRM_I915_GET_VBLANK_PIPE	0x0e
 #define DRM_I915_VBLANK_SWAP	0x0f
 #define DRM_I915_HWS_ADDR	0x11
+#define DRM_I915_GEM_INIT	0x13
+#define DRM_I915_GEM_EXECBUFFER	0x14
+#define DRM_I915_GEM_PIN	0x15
+#define DRM_I915_GEM_UNPIN	0x16
+#define DRM_I915_GEM_BUSY	0x17
+#define DRM_I915_GEM_THROTTLE	0x18
+#define DRM_I915_GEM_ENTERVT	0x19
+#define DRM_I915_GEM_LEAVEVT	0x1a
+#define DRM_I915_GEM_CREATE	0x1b
+#define DRM_I915_GEM_PREAD	0x1c
+#define DRM_I915_GEM_PWRITE	0x1d
+#define DRM_I915_GEM_MMAP	0x1e
+#define DRM_I915_GEM_SET_DOMAIN	0x1f
+#define DRM_I915_GEM_SW_FINISH	0x20
+#define DRM_I915_GEM_SET_TILING	0x21
+#define DRM_I915_GEM_GET_TILING	0x22
 
 #define DRM_IOCTL_I915_INIT		DRM_IOW( DRM_COMMAND_BASE + DRM_I915_INIT, drm_i915_init_t)
 #define DRM_IOCTL_I915_FLUSH		DRM_IO ( DRM_COMMAND_BASE + DRM_I915_FLUSH)
@@ -160,6 +176,20 @@ typedef struct _drm_i915_sarea {
 #define DRM_IOCTL_I915_SET_VBLANK_PIPE	DRM_IOW( DRM_COMMAND_BASE + DRM_I915_SET_VBLANK_PIPE, drm_i915_vblank_pipe_t)
 #define DRM_IOCTL_I915_GET_VBLANK_PIPE	DRM_IOR( DRM_COMMAND_BASE + DRM_I915_GET_VBLANK_PIPE, drm_i915_vblank_pipe_t)
 #define DRM_IOCTL_I915_VBLANK_SWAP	DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_VBLANK_SWAP, drm_i915_vblank_swap_t)
+#define DRM_IOCTL_I915_GEM_PIN		DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_GEM_PIN, struct drm_i915_gem_pin)
+#define DRM_IOCTL_I915_GEM_UNPIN	DRM_IOW(DRM_COMMAND_BASE + DRM_I915_GEM_UNPIN, struct drm_i915_gem_unpin)
+#define DRM_IOCTL_I915_GEM_BUSY		DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_GEM_BUSY, struct drm_i915_gem_busy)
+#define DRM_IOCTL_I915_GEM_THROTTLE	DRM_IO ( DRM_COMMAND_BASE + DRM_I915_GEM_THROTTLE)
+#define DRM_IOCTL_I915_GEM_ENTERVT	DRM_IO(DRM_COMMAND_BASE + DRM_I915_GEM_ENTERVT)
+#define DRM_IOCTL_I915_GEM_LEAVEVT	DRM_IO(DRM_COMMAND_BASE + DRM_I915_GEM_LEAVEVT)
+#define DRM_IOCTL_I915_GEM_CREATE	DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_GEM_CREATE, struct drm_i915_gem_create)
+#define DRM_IOCTL_I915_GEM_PREAD	DRM_IOW (DRM_COMMAND_BASE + DRM_I915_GEM_PREAD, struct drm_i915_gem_pread)
+#define DRM_IOCTL_I915_GEM_PWRITE	DRM_IOW (DRM_COMMAND_BASE + DRM_I915_GEM_PWRITE, struct drm_i915_gem_pwrite)
+#define DRM_IOCTL_I915_GEM_MMAP		DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_GEM_MMAP, struct drm_i915_gem_mmap)
+#define DRM_IOCTL_I915_GEM_SET_DOMAIN	DRM_IOW (DRM_COMMAND_BASE + DRM_I915_GEM_SET_DOMAIN, struct drm_i915_gem_set_domain)
+#define DRM_IOCTL_I915_GEM_SW_FINISH	DRM_IOW (DRM_COMMAND_BASE + DRM_I915_GEM_SW_FINISH, struct drm_i915_gem_sw_finish)
+#define DRM_IOCTL_I915_GEM_SET_TILING	DRM_IOWR (DRM_COMMAND_BASE + DRM_I915_GEM_SET_TILING, struct drm_i915_gem_set_tiling)
+#define DRM_IOCTL_I915_GEM_GET_TILING	DRM_IOWR (DRM_COMMAND_BASE + DRM_I915_GEM_GET_TILING, struct drm_i915_gem_get_tiling)
 
 /* Allow drivers to submit batchbuffers directly to hardware, relying
  * on the security mechanisms provided by hardware.
@@ -200,6 +230,7 @@ typedef struct drm_i915_irq_wait {
 #define I915_PARAM_IRQ_ACTIVE            1
 #define I915_PARAM_ALLOW_BATCHBUFFER     2
 #define I915_PARAM_LAST_DISPATCH         3
+#define I915_PARAM_HAS_GEM               5
 
 typedef struct drm_i915_getparam {
 	int param;
@@ -267,4 +298,305 @@ typedef struct drm_i915_hws_addr {
 	uint64_t addr;
 } drm_i915_hws_addr_t;
 
+struct drm_i915_gem_init {
+	/**
+	 * Beginning offset in the GTT to be managed by the DRM memory
+	 * manager.
+	 */
+	uint64_t gtt_start;
+	/**
+	 * Ending offset in the GTT to be managed by the DRM memory
+	 * manager.
+	 */
+	uint64_t gtt_end;
+};
+
+struct drm_i915_gem_create {
+	/**
+	 * Requested size for the object.
+	 *
+	 * The (page-aligned) allocated size for the object will be returned.
+	 */
+	uint64_t size;
+	/**
+	 * Returned handle for the object.
+	 *
+	 * Object handles are nonzero.
+	 */
+	uint32_t handle;
+	uint32_t pad;
+};
+
+struct drm_i915_gem_pread {
+	/** Handle for the object being read. */
+	uint32_t handle;
+	uint32_t pad;
+	/** Offset into the object to read from */
+	uint64_t offset;
+	/** Length of data to read */
+	uint64_t size;
+	/**
+	 * Pointer to write the data into.
+	 *
+	 * This is a fixed-size type for 32/64 compatibility.
+	 */
+	uint64_t data_ptr;
+};
+
+struct drm_i915_gem_pwrite {
+	/** Handle for the object being written to. */
+	uint32_t handle;
+	uint32_t pad;
+	/** Offset into the object to write to */
+	uint64_t offset;
+	/** Length of data to write */
+	uint64_t size;
+	/**
+	 * Pointer to read the data from.
+	 *
+	 * This is a fixed-size type for 32/64 compatibility.
+	 */
+	uint64_t data_ptr;
+};
+
+struct drm_i915_gem_mmap {
+	/** Handle for the object being mapped. */
+	uint32_t handle;
+	uint32_t pad;
+	/** Offset in the object to map. */
+	uint64_t offset;
+	/**
+	 * Length of data to map.
+	 *
+	 * The value will be page-aligned.
+	 */
+	uint64_t size;
+	/**
+	 * Returned pointer the data was mapped at.
+	 *
+	 * This is a fixed-size type for 32/64 compatibility.
+	 */
+	uint64_t addr_ptr;
+};
+
+struct drm_i915_gem_set_domain {
+	/** Handle for the object */
+	uint32_t handle;
+
+	/** New read domains */
+	uint32_t read_domains;
+
+	/** New write domain */
+	uint32_t write_domain;
+};
+
+struct drm_i915_gem_sw_finish {
+	/** Handle for the object */
+	uint32_t handle;
+};
+
+struct drm_i915_gem_relocation_entry {
+	/**
+	 * Handle of the buffer being pointed to by this relocation entry.
+	 *
+	 * It's appealing to make this be an index into the mm_validate_entry
+	 * list to refer to the buffer, but this allows the driver to create
+	 * a relocation list for state buffers and not re-write it per
+	 * exec using the buffer.
+	 */
+	uint32_t target_handle;
+
+	/**
+	 * Value to be added to the offset of the target buffer to make up
+	 * the relocation entry.
+	 */
+	uint32_t delta;
+
+	/** Offset in the buffer the relocation entry will be written into */
+	uint64_t offset;
+
+	/**
+	 * Offset value of the target buffer that the relocation entry was last
+	 * written as.
+	 *
+	 * If the buffer has the same offset as last time, we can skip syncing
+	 * and writing the relocation.  This value is written back out by
+	 * the execbuffer ioctl when the relocation is written.
+	 */
+	uint64_t presumed_offset;
+
+	/**
+	 * Target memory domains read by this operation.
+	 */
+	uint32_t read_domains;
+
+	/**
+	 * Target memory domains written by this operation.
+	 *
+	 * Note that only one domain may be written by the whole
+	 * execbuffer operation, so that where there are conflicts,
+	 * the application will get -EINVAL back.
+	 */
+	uint32_t write_domain;
+};
+
+/** @{
+ * Intel memory domains
+ *
+ * Most of these just align with the various caches in
+ * the system and are used to flush and invalidate as
+ * objects end up cached in different domains.
+ */
+/** CPU cache */
+#define I915_GEM_DOMAIN_CPU		0x00000001
+/** Render cache, used by 2D and 3D drawing */
+#define I915_GEM_DOMAIN_RENDER		0x00000002
+/** Sampler cache, used by texture engine */
+#define I915_GEM_DOMAIN_SAMPLER		0x00000004
+/** Command queue, used to load batch buffers */
+#define I915_GEM_DOMAIN_COMMAND		0x00000008
+/** Instruction cache, used by shader programs */
+#define I915_GEM_DOMAIN_INSTRUCTION	0x00000010
+/** Vertex address cache */
+#define I915_GEM_DOMAIN_VERTEX		0x00000020
+/** GTT domain - aperture and scanout */
+#define I915_GEM_DOMAIN_GTT		0x00000040
+/** @} */
+
+struct drm_i915_gem_exec_object {
+	/**
+	 * User's handle for a buffer to be bound into the GTT for this
+	 * operation.
+	 */
+	uint32_t handle;
+
+	/** Number of relocations to be performed on this buffer */
+	uint32_t relocation_count;
+	/**
+	 * Pointer to array of struct drm_i915_gem_relocation_entry containing
+	 * the relocations to be performed in this buffer.
+	 */
+	uint64_t relocs_ptr;
+
+	/** Required alignment in graphics aperture */
+	uint64_t alignment;
+
+	/**
+	 * Returned value of the updated offset of the object, for future
+	 * presumed_offset writes.
+	 */
+	uint64_t offset;
+};
+
+struct drm_i915_gem_execbuffer {
+	/**
+	 * List of buffers to be validated with their relocations to be
+	 * performend on them.
+	 *
+	 * This is a pointer to an array of struct drm_i915_gem_validate_entry.
+	 *
+	 * These buffers must be listed in an order such that all relocations
+	 * a buffer is performing refer to buffers that have already appeared
+	 * in the validate list.
+	 */
+	uint64_t buffers_ptr;
+	uint32_t buffer_count;
+
+	/** Offset in the batchbuffer to start execution from. */
+	uint32_t batch_start_offset;
+	/** Bytes used in batchbuffer from batch_start_offset */
+	uint32_t batch_len;
+	uint32_t DR1;
+	uint32_t DR4;
+	uint32_t num_cliprects;
+	/** This is a struct drm_clip_rect *cliprects */
+	uint64_t cliprects_ptr;
+};
+
+struct drm_i915_gem_pin {
+	/** Handle of the buffer to be pinned. */
+	uint32_t handle;
+	uint32_t pad;
+
+	/** alignment required within the aperture */
+	uint64_t alignment;
+
+	/** Returned GTT offset of the buffer. */
+	uint64_t offset;
+};
+
+struct drm_i915_gem_unpin {
+	/** Handle of the buffer to be unpinned. */
+	uint32_t handle;
+	uint32_t pad;
+};
+
+struct drm_i915_gem_busy {
+	/** Handle of the buffer to check for busy */
+	uint32_t handle;
+
+	/** Return busy status (1 if busy, 0 if idle) */
+	uint32_t busy;
+};
+
+#define I915_TILING_NONE	0
+#define I915_TILING_X		1
+#define I915_TILING_Y		2
+
+#define I915_BIT_6_SWIZZLE_NONE		0
+#define I915_BIT_6_SWIZZLE_9		1
+#define I915_BIT_6_SWIZZLE_9_10		2
+#define I915_BIT_6_SWIZZLE_9_11		3
+#define I915_BIT_6_SWIZZLE_9_10_11	4
+/* Not seen by userland */
+#define I915_BIT_6_SWIZZLE_UNKNOWN	5
+
+struct drm_i915_gem_set_tiling {
+	/** Handle of the buffer to have its tiling state updated */
+	uint32_t handle;
+
+	/**
+	 * Tiling mode for the object (I915_TILING_NONE, I915_TILING_X,
+	 * I915_TILING_Y).
+	 *
+	 * This value is to be set on request, and will be updated by the
+	 * kernel on successful return with the actual chosen tiling layout.
+	 *
+	 * The tiling mode may be demoted to I915_TILING_NONE when the system
+	 * has bit 6 swizzling that can't be managed correctly by GEM.
+	 *
+	 * Buffer contents become undefined when changing tiling_mode.
+	 */
+	uint32_t tiling_mode;
+
+	/**
+	 * Stride in bytes for the object when in I915_TILING_X or
+	 * I915_TILING_Y.
+	 */
+	uint32_t stride;
+
+	/**
+	 * Returned address bit 6 swizzling required for CPU access through
+	 * mmap mapping.
+	 */
+	uint32_t swizzle_mode;
+};
+
+struct drm_i915_gem_get_tiling {
+	/** Handle of the buffer to get tiling state for. */
+	uint32_t handle;
+
+	/**
+	 * Current tiling mode for the object (I915_TILING_NONE, I915_TILING_X,
+	 * I915_TILING_Y).
+	 */
+	uint32_t tiling_mode;
+
+	/**
+	 * Returned address bit 6 swizzling required for CPU access through
+	 * mmap mapping.
+	 */
+	uint32_t swizzle_mode;
+};
+
 #endif				/* _I915_DRM_H_ */