drm/i915/gt: Create per-gt debugfs files

To support multi-GT configurations, we need to generate
independent debug files for each GT.

To achieve this create a separate directory for each GT under the
debugfs directory. For instance, in a system with two GTs, the
debugfs structure would look like this:

/sys/kernel/debug/dri
                  └── 0
                      ├── gt0
                      │   ├── drpc
                      │   ├── engines
                      │   ├── forcewake
                      │   ├── frequency
                      │   └── rps_boost
                      └── gt1
                      :   ├── drpc
                      :   ├── engines
                      :   ├── forcewake
                          ├── frequency
                          └── rps_boost
Signed-off-by: Andi Shyti <andi.shyti@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230318203616.183765-2-andi.shyti@linux.intel.com

drivers/gpu/drm/i915/gt/intel_gt_debugfs.c

@@ -83,11 +83,13 @@ static void gt_debugfs_register(struct intel_gt *gt, struct dentry *root)
 void intel_gt_debugfs_register(struct intel_gt *gt)
 {
 	struct dentry *root;
+	char gtname[4];
 
 	if (!gt->i915->drm.primary->debugfs_root)
 		return;
 
-	root = debugfs_create_dir("gt", gt->i915->drm.primary->debugfs_root);
+	snprintf(gtname, sizeof(gtname), "gt%u", gt->info.id);
+	root = debugfs_create_dir(gtname, gt->i915->drm.primary->debugfs_root);
 	if (IS_ERR(root))
 		return;
 

drivers/gpu/drm/i915/gt/uc/intel_guc.h

@@ -42,6 +42,8 @@ struct intel_guc {
 	/** @capture: the error-state-capture module's data and objects */
 	struct intel_guc_state_capture *capture;
 
+	struct dentry *dbgfs_node;
+
 	/** @sched_engine: Global engine used to submit requests to GuC */
 	struct i915_sched_engine *sched_engine;
 	/**

drivers/gpu/drm/i915/gt/uc/intel_guc_log.c

@@ -542,8 +542,11 @@ static int guc_log_relay_create(struct intel_guc_log *log)
 	 */
 	n_subbufs = 8;
 
+	if (!guc->dbgfs_node)
+		return -ENOENT;
+
 	guc_log_relay_chan = relay_open("guc_log",
-					i915->drm.primary->debugfs_root,
+					guc->dbgfs_node,
 					subbuf_size, n_subbufs,
 					&relay_callbacks, i915);
 	if (!guc_log_relay_chan) {

drivers/gpu/drm/i915/gt/uc/intel_uc_debugfs.c

@@ -54,6 +54,8 @@ void intel_uc_debugfs_register(struct intel_uc *uc, struct dentry *gt_root)
 	if (IS_ERR(root))
 		return;
 
+	uc->guc.dbgfs_node = root;
+
 	intel_gt_debugfs_register_files(root, files, ARRAY_SIZE(files), uc);
 
 	intel_guc_debugfs_register(&uc->guc, root);