i915: Add GEM ioctl to get available aperture size.

This will let userland know when to submit its batchbuffers, before they get
too big to fit in the aperture.
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/i915/i915_dma.c

@@ -960,6 +960,7 @@ struct drm_ioctl_desc i915_ioctls[] = {
 	DRM_IOCTL_DEF(DRM_I915_GEM_SW_FINISH, i915_gem_sw_finish_ioctl, 0),
 	DRM_IOCTL_DEF(DRM_I915_GEM_SET_TILING, i915_gem_set_tiling, 0),
 	DRM_IOCTL_DEF(DRM_I915_GEM_GET_TILING, i915_gem_get_tiling, 0),
+	DRM_IOCTL_DEF(DRM_I915_GEM_GET_APERTURE, i915_gem_get_aperture_ioctl, 0),
 };
 
 int i915_max_ioctl = DRM_ARRAY_SIZE(i915_ioctls);

drivers/gpu/drm/i915/i915_drv.h

@@ -502,6 +502,8 @@ int i915_gem_set_tiling(struct drm_device *dev, void *data,
 			struct drm_file *file_priv);
 int i915_gem_get_tiling(struct drm_device *dev, void *data,
 			struct drm_file *file_priv);
+int i915_gem_get_aperture_ioctl(struct drm_device *dev, void *data,
+				struct drm_file *file_priv);
 void i915_gem_load(struct drm_device *dev);
 int i915_gem_proc_init(struct drm_minor *minor);
 void i915_gem_proc_cleanup(struct drm_minor *minor);

drivers/gpu/drm/i915/i915_gem.c

@@ -79,6 +79,28 @@ i915_gem_init_ioctl(struct drm_device *dev, void *data,
 	return 0;
 }
 
+int
+i915_gem_get_aperture_ioctl(struct drm_device *dev, void *data,
+			    struct drm_file *file_priv)
+{
+	drm_i915_private_t *dev_priv = dev->dev_private;
+	struct drm_i915_gem_get_aperture *args = data;
+	struct drm_i915_gem_object *obj_priv;
+
+	if (!(dev->driver->driver_features & DRIVER_GEM))
+		return -ENODEV;
+
+	args->aper_size = dev->gtt_total;
+	args->aper_available_size = args->aper_size;
+
+	list_for_each_entry(obj_priv, &dev_priv->mm.active_list, list) {
+		if (obj_priv->pin_count > 0)
+			args->aper_available_size -= obj_priv->obj->size;
+	}
+
+	return 0;
+}
+
 
 /**
  * Creates a new mm object and returns a handle to it.

include/drm/i915_drm.h

@@ -159,6 +159,7 @@ typedef struct _drm_i915_sarea {
 #define DRM_I915_GEM_SW_FINISH	0x20
 #define DRM_I915_GEM_SET_TILING	0x21
 #define DRM_I915_GEM_GET_TILING	0x22
+#define DRM_I915_GEM_GET_APERTURE 0x23
 
 #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)
@@ -190,6 +191,7 @@ typedef struct _drm_i915_sarea {
 #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)
+#define DRM_IOCTL_I915_GEM_GET_APERTURE	DRM_IOR  (DRM_COMMAND_BASE + DRM_I915_GEM_GET_APERTURE, struct drm_i915_gem_get_aperture)
 
 /* Allow drivers to submit batchbuffers directly to hardware, relying
  * on the security mechanisms provided by hardware.
@@ -600,4 +602,15 @@ struct drm_i915_gem_get_tiling {
 	uint32_t swizzle_mode;
 };
 
+struct drm_i915_gem_get_aperture {
+	/** Total size of the aperture used by i915_gem_execbuffer, in bytes */
+	uint64_t aper_size;
+
+	/**
+	 * Available space in the aperture used by i915_gem_execbuffer, in
+	 * bytes
+	 */
+	uint64_t aper_available_size;
+};
+
 #endif				/* _I915_DRM_H_ */