[Intel-gfx] [PATCH v2] drm/i915: IOCTL to query the cache level of a BO.

[Ben Widawsky]

Querying a BO's cache level can help clients wishing to map the buffer.
For example, an Ironlake machine could query the buffer to determine it
should use GTT mappings, while a Sandybridge machine running the same
code would prefer to use regular CPU mapped buffers since the cache is
coherent.

Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
Cc: Eric Anholt <eric at anholt.net>
Cc: "Kilarski, Bernard R" <bernard.r.kilarski at intel.com>
Signed-off-by: Ben Widawsky <ben at bwidawsk.net>
---
 drivers/gpu/drm/i915/i915_dma.c |    1 +
 drivers/gpu/drm/i915/i915_drv.h |    2 ++
 drivers/gpu/drm/i915/i915_gem.c |   22 ++++++++++++++++++++++
 include/drm/i915_drm.h          |    7 +++++++
 4 files changed, 32 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index 8a3942c..8178cbb 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -2292,6 +2292,7 @@ struct drm_ioctl_desc i915_ioctls[] = {
 	DRM_IOCTL_DEF_DRV(I915_GEM_MADVISE, i915_gem_madvise_ioctl, DRM_UNLOCKED),
 	DRM_IOCTL_DEF_DRV(I915_OVERLAY_PUT_IMAGE, intel_overlay_put_image, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
 	DRM_IOCTL_DEF_DRV(I915_OVERLAY_ATTRS, intel_overlay_attrs, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
+	DRM_IOCTL_DEF_DRV(I915_GEM_GET_CACHE_TYPE, i915_gem_get_cache_type_ioctl, DRM_UNLOCKED),
 };
 
 int i915_max_ioctl = DRM_ARRAY_SIZE(i915_ioctls);
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 7916bd9..2dfcb3d 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1118,6 +1118,8 @@ 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);
+int i915_gem_get_cache_type_ioctl(struct drm_device *dev, void *data,
+				  struct drm_file *file_priv);
 void i915_gem_load(struct drm_device *dev);
 int i915_gem_init_object(struct drm_gem_object *obj);
 int __must_check i915_gem_flush_ring(struct intel_ring_buffer *ring,
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index a546a71..a120a74 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -3777,6 +3777,28 @@ void i915_gem_free_object(struct drm_gem_object *gem_obj)
 }
 
 int
+i915_gem_get_cache_type_ioctl(struct drm_device *dev, void *data,
+			      struct drm_file *file_priv)
+{
+
+	struct drm_i915_gem_get_cache_type *args = data;
+	struct drm_i915_gem_object *obj;
+	int ret = 0;
+
+	obj = to_intel_bo(drm_gem_object_lookup(dev, file_priv, args->handle));
+	if (&obj->base == NULL) {
+		ret = -ENOENT;
+		goto out;
+	}
+
+	args->cache_level = obj->cache_level;
+	drm_gem_object_unreference_unlocked(&obj->base);
+
+out:
+	return ret;
+}
+
+int
 i915_gem_idle(struct drm_device *dev)
 {
 	drm_i915_private_t *dev_priv = dev->dev_private;
diff --git a/include/drm/i915_drm.h b/include/drm/i915_drm.h
index 28c0d11..a0dff8a 100644
--- a/include/drm/i915_drm.h
+++ b/include/drm/i915_drm.h
@@ -198,6 +198,7 @@ typedef struct _drm_i915_sarea {
 #define DRM_I915_OVERLAY_PUT_IMAGE	0x27
 #define DRM_I915_OVERLAY_ATTRS	0x28
 #define DRM_I915_GEM_EXECBUFFER2	0x29
+#define DRM_I915_GEM_GET_CACHE_TYPE	0x2a
 
 #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)
@@ -239,6 +240,7 @@ typedef struct _drm_i915_sarea {
 #define DRM_IOCTL_I915_GEM_MADVISE	DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_GEM_MADVISE, struct drm_i915_gem_madvise)
 #define DRM_IOCTL_I915_OVERLAY_PUT_IMAGE	DRM_IOW(DRM_COMMAND_BASE + DRM_I915_OVERLAY_PUT_IMAGE, struct drm_intel_overlay_put_image)
 #define DRM_IOCTL_I915_OVERLAY_ATTRS	DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_OVERLAY_ATTRS, struct drm_intel_overlay_attrs)
+#define DRM_IOCTL_I915_GEM_GET_CACHE_TYPE	DRM_IOR  (DRM_COMMAND_BASE + DRM_I915_GEM_GET_CACHE_TYPE, struct drm_i915_gem_get_cache_type)
 
 /* Allow drivers to submit batchbuffers directly to hardware, relying
  * on the security mechanisms provided by hardware.
@@ -844,4 +846,9 @@ struct drm_intel_overlay_attrs {
 	__u32 gamma5;
 };
 
+struct drm_i915_gem_get_cache_type {
+	__u32 handle;
+	__u32 cache_level;
+};
+
 #endif				/* _I915_DRM_H_ */
-- 
1.7.6.3