drm/i915: Use ilk_wm_max_level() in latency debugfs files

Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
[danvet: Squash in patch that exported ilk_wm_max_level.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_debugfs.c

@@ -3124,7 +3124,7 @@ static const struct file_operations i915_display_crc_ctl_fops = {
 static void wm_latency_show(struct seq_file *m, const uint16_t wm[5])
 {
 	struct drm_device *dev = m->private;
-	int num_levels = IS_HASWELL(dev) || IS_BROADWELL(dev) ? 5 : 4;
+	int num_levels = ilk_wm_max_level(dev) + 1;
 	int level;
 
 	drm_modeset_lock_all(dev);
@@ -3207,7 +3207,7 @@ static ssize_t wm_latency_write(struct file *file, const char __user *ubuf,
 	struct seq_file *m = file->private_data;
 	struct drm_device *dev = m->private;
 	uint16_t new[5] = { 0 };
-	int num_levels = IS_HASWELL(dev) || IS_BROADWELL(dev) ? 5 : 4;
+	int num_levels = ilk_wm_max_level(dev) + 1;
 	int level;
 	int ret;
 	char tmp[32];

drivers/gpu/drm/i915/intel_drv.h

@@ -917,6 +917,7 @@ extern struct drm_display_mode *intel_find_panel_downclock(
 /* intel_pm.c */
 void intel_init_clock_gating(struct drm_device *dev);
 void intel_suspend_hw(struct drm_device *dev);
+int ilk_wm_max_level(const struct drm_device *dev);
 void intel_update_watermarks(struct drm_crtc *crtc);
 void intel_update_sprite_watermarks(struct drm_plane *plane,
 				    struct drm_crtc *crtc,

drivers/gpu/drm/i915/intel_pm.c

@@ -2077,7 +2077,7 @@ static void intel_fixup_cur_wm_latency(struct drm_device *dev, uint16_t wm[5])
 		wm[3] *= 2;
 }
 
-static int ilk_wm_max_level(const struct drm_device *dev)
+int ilk_wm_max_level(const struct drm_device *dev)
 {
 	/* how many WM levels are we expecting */
 	if (IS_HASWELL(dev) || IS_BROADWELL(dev))