drm/i915: add i915_get_reset_stats_ioctl

This ioctl returns reset stats for specified context.

The struct returned contains context loss counters.

reset_count:    all resets across all contexts
batch_active:   active batches lost on resets
batch_pending:  pending batches lost on resets

v2: get rid of state tracking completely and deliver only counts. Idea
    from Chris Wilson.

v3: fix commit message

v4: default context handled inside i915_gem_context_get_hang_stats

v5: reset_count only for priviledged process

v6: ctx=0 needs CAP_SYS_ADMIN for batch_* counters (Chris Wilson)

v7: context hang stats never returns NULL

v8: rebased on top of reworked context hang stats
    DRM_RENDER_ALLOW for ioctl

v9: use DEFAULT_CONTEXT_ID. Improve comments for ioctl struct members

Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: Ian Romanick <idr@freedesktop.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index 3a4e97b..52aed89 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -222,6 +222,7 @@
 #define DRM_I915_GEM_SET_CACHING	0x2f
 #define DRM_I915_GEM_GET_CACHING	0x30
 #define DRM_I915_REG_READ		0x31
+#define DRM_I915_GET_RESET_STATS	0x32
 
 #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)
@@ -271,6 +272,7 @@
 #define DRM_IOCTL_I915_GEM_CONTEXT_CREATE	DRM_IOWR (DRM_COMMAND_BASE + DRM_I915_GEM_CONTEXT_CREATE, struct drm_i915_gem_context_create)
 #define DRM_IOCTL_I915_GEM_CONTEXT_DESTROY	DRM_IOW (DRM_COMMAND_BASE + DRM_I915_GEM_CONTEXT_DESTROY, struct drm_i915_gem_context_destroy)
 #define DRM_IOCTL_I915_REG_READ			DRM_IOWR (DRM_COMMAND_BASE + DRM_I915_REG_READ, struct drm_i915_reg_read)
+#define DRM_IOCTL_I915_GET_RESET_STATS		DRM_IOWR (DRM_COMMAND_BASE + DRM_I915_GET_RESET_STATS, struct drm_i915_reset_stats)
 
 /* Allow drivers to submit batchbuffers directly to hardware, relying
  * on the security mechanisms provided by hardware.
@@ -1030,4 +1032,21 @@
 	__u64 offset;
 	__u64 val; /* Return value */
 };
+
+struct drm_i915_reset_stats {
+	__u32 ctx_id;
+	__u32 flags;
+
+	/* All resets since boot/module reload, for all contexts */
+	__u32 reset_count;
+
+	/* Number of batches lost when active in GPU, for this context */
+	__u32 batch_active;
+
+	/* Number of batches lost pending for execution, for this context */
+	__u32 batch_pending;
+
+	__u32 pad;
+};
+
 #endif /* _UAPI_I915_DRM_H_ */