drm/kms/radeon: Add support for precise vblank timestamping.

This patch adds new functions for use by the drm core:

.get_vblank_timestamp() provides a precise timestamp
for the end of the most recent (or current) vblank
interval of a given crtc, as needed for the DRI2
implementation of the OML_sync_control extension.

It is a thin wrapper around the drm function
drm_calc_vbltimestamp_from_scanoutpos() which does
almost all the work and is shared across drivers.

.get_scanout_position() provides the current horizontal
and vertical video scanout position and "in vblank"
status of a given crtc, as needed by the drm for use by
drm_calc_vbltimestamp_from_scanoutpos().

The function is also used by the dynamic gpu reclocking
code to determine when it is safe to reclock inside vblank.

For that purpose radeon_pm_in_vbl() is modified to
accomodate a small change in the function prototype of
the radeon_get_crtc_scanoutpos() which is hooked up to
.get_scanout_position().

This code has been tested on AVIVO hardware, a RV530
(ATI Mobility Radeon X1600) in a Intel Core-2 Duo MacBookPro
and some R600 variant (FireGL V7600) in a single cpu
AMD Athlon 64 PC.

Signed-off-by: Mario Kleiner <mario.kleiner@tuebingen.mpg.de>
Reviewed-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/radeon_drv.c b/drivers/gpu/drm/radeon/radeon_drv.c
index 88e4ea9..32ec0cc 100644
--- a/drivers/gpu/drm/radeon/radeon_drv.c
+++ b/drivers/gpu/drm/radeon/radeon_drv.c
@@ -66,6 +66,10 @@
 u32 radeon_get_vblank_counter_kms(struct drm_device *dev, int crtc);
 int radeon_enable_vblank_kms(struct drm_device *dev, int crtc);
 void radeon_disable_vblank_kms(struct drm_device *dev, int crtc);
+int radeon_get_vblank_timestamp_kms(struct drm_device *dev, int crtc,
+				    int *max_error,
+				    struct timeval *vblank_time,
+				    unsigned flags);
 void radeon_driver_irq_preinstall_kms(struct drm_device *dev);
 int radeon_driver_irq_postinstall_kms(struct drm_device *dev);
 void radeon_driver_irq_uninstall_kms(struct drm_device *dev);
@@ -74,6 +78,8 @@
 			 struct drm_file *file_priv);
 int radeon_gem_object_init(struct drm_gem_object *obj);
 void radeon_gem_object_free(struct drm_gem_object *obj);
+extern int radeon_get_crtc_scanoutpos(struct drm_device *dev, int crtc,
+				      int *vpos, int *hpos);
 extern struct drm_ioctl_desc radeon_ioctls_kms[];
 extern int radeon_max_kms_ioctl;
 int radeon_mmap(struct file *filp, struct vm_area_struct *vma);
@@ -277,6 +283,8 @@
 	.get_vblank_counter = radeon_get_vblank_counter_kms,
 	.enable_vblank = radeon_enable_vblank_kms,
 	.disable_vblank = radeon_disable_vblank_kms,
+	.get_vblank_timestamp = radeon_get_vblank_timestamp_kms,
+	.get_scanout_position = radeon_get_crtc_scanoutpos,
 #if defined(CONFIG_DEBUG_FS)
 	.debugfs_init = radeon_debugfs_init,
 	.debugfs_cleanup = radeon_debugfs_cleanup,