drm/i915: Expose SAGV state via debugfs

Since SAGV is controlled via unidirectional pcode commands
we have no way to query the current state. So instead let's
expose the last programmed state via debugfs. This way we
can at least know whether SAGV should be enabled or not
(which can be important to know when dealing with underruns/etc.).
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230131002127.29305-4-ville.syrjala@linux.intel.comReviewed-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/display/intel_display_debugfs.c

@@ -1622,7 +1622,7 @@ void intel_display_debugfs_register(struct drm_i915_private *i915)
 	intel_dmc_debugfs_register(i915);
 	intel_fbc_debugfs_register(i915);
 	intel_hpd_debugfs_register(i915);
-	skl_watermark_ipc_debugfs_register(i915);
+	skl_watermark_debugfs_register(i915);
 }
 
 static int i915_panel_show(struct seq_file *m, void *data)

drivers/gpu/drm/i915/display/skl_watermark.c

@@ -3545,13 +3545,34 @@ static const struct file_operations skl_watermark_ipc_status_fops = {
 	.write = skl_watermark_ipc_status_write
 };
 
-void skl_watermark_ipc_debugfs_register(struct drm_i915_private *i915)
+static int intel_sagv_status_show(struct seq_file *m, void *unused)
+{
+	struct drm_i915_private *i915 = m->private;
+	static const char * const sagv_status[] = {
+		[I915_SAGV_UNKNOWN] = "unknown",
+		[I915_SAGV_DISABLED] = "disabled",
+		[I915_SAGV_ENABLED] = "enabled",
+		[I915_SAGV_NOT_CONTROLLED] = "not controlled",
+	};
+
+	seq_printf(m, "SAGV available: %s\n", str_yes_no(intel_has_sagv(i915)));
+	seq_printf(m, "SAGV status: %s\n", sagv_status[i915->display.sagv.status]);
+	seq_printf(m, "SAGV block time: %d usec\n", i915->display.sagv.block_time_us);
+
+	return 0;
+}
+
+DEFINE_SHOW_ATTRIBUTE(intel_sagv_status);
+
+void skl_watermark_debugfs_register(struct drm_i915_private *i915)
 {
 	struct drm_minor *minor = i915->drm.primary;
 
-	if (!HAS_IPC(i915))
-		return;
+	if (HAS_IPC(i915))
+		debugfs_create_file("i915_ipc_status", 0644, minor->debugfs_root, i915,
+				    &skl_watermark_ipc_status_fops);
 
-	debugfs_create_file("i915_ipc_status", 0644, minor->debugfs_root, i915,
-			    &skl_watermark_ipc_status_fops);
+	if (HAS_SAGV(i915))
+		debugfs_create_file("i915_sagv_status", 0444, minor->debugfs_root, i915,
+				    &intel_sagv_status_fops);
 }

drivers/gpu/drm/i915/display/skl_watermark.h

@@ -47,7 +47,7 @@ void intel_wm_state_verify(struct intel_crtc *crtc,
 void skl_watermark_ipc_init(struct drm_i915_private *i915);
 void skl_watermark_ipc_update(struct drm_i915_private *i915);
 bool skl_watermark_ipc_enabled(struct drm_i915_private *i915);
-void skl_watermark_ipc_debugfs_register(struct drm_i915_private *i915);
+void skl_watermark_debugfs_register(struct drm_i915_private *i915);
 
 void skl_wm_init(struct drm_i915_private *i915);