drm/xe: Add sysfs entry for tile

We have recently introduced tile for each gpu,
so lets add sysfs entry per tile for userspace
to provide required information specific to tile.

V5:
- define ktype as const
V4:
- Reorder headers - Aravind
V3:
- Make API to return void and add drm_warn - Aravind
V2:
- Add logs in failure path

Reviewed-by: Aravind Iddamsetty <[e-mail]>
Signed-off-by: Tejas Upadhyay <[e-mail]>
Signed-off-by: Rodrigo Vivi <[e-mail]>

drivers/gpu/drm/xe/Makefile

···
 	xe_step.o \
 	xe_sync.o \
 	xe_tile.o \
+	xe_tile_sysfs.o \
 	xe_trace.o \
 	xe_ttm_sys_mgr.o \
 	xe_ttm_stolen_mgr.o \

drivers/gpu/drm/xe/xe_device_types.h

···
 
 	/** @migrate: Migration helper for vram blits and clearing */
 	struct xe_migrate *migrate;
+
+	/** @sysfs: sysfs' kobj used by xe_tile_sysfs */
+	struct kobject *sysfs;
 };
 
 /**

drivers/gpu/drm/xe/xe_tile.c

···
 #include "xe_migrate.h"
 #include "xe_sa.h"
 #include "xe_tile.h"
+#include "xe_tile_sysfs.h"
 #include "xe_ttm_vram_mgr.h"
 
 /**
···
 	tile->mem.kernel_bb_pool = xe_sa_bo_manager_init(tile, SZ_1M, 16);
 	if (IS_ERR(tile->mem.kernel_bb_pool))
 		err = PTR_ERR(tile->mem.kernel_bb_pool);
+
+	xe_tile_sysfs_init(tile);
 
 err_mem_access:
 	xe_device_mem_access_put(tile_to_xe(tile));

drivers/gpu/drm/xe/xe_tile.h

···
 #ifndef _XE_TILE_H_
 #define _XE_TILE_H_
 
+#include "xe_device_types.h"
+
 struct xe_tile;
 
 int xe_tile_alloc(struct xe_tile *tile);

drivers/gpu/drm/xe/xe_tile_sysfs.c

···
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2023 Intel Corporation
+ */
+
+#include <linux/kobject.h>
+#include <linux/sysfs.h>
+#include <drm/drm_managed.h>
+
+#include "xe_tile.h"
+#include "xe_tile_sysfs.h"
+
+static void xe_tile_sysfs_kobj_release(struct kobject *kobj)
+{
+	kfree(kobj);
+}
+
+static const struct kobj_type xe_tile_sysfs_kobj_type = {
+	.release = xe_tile_sysfs_kobj_release,
+	.sysfs_ops = &kobj_sysfs_ops,
+};
+
+static void tile_sysfs_fini(struct drm_device *drm, void *arg)
+{
+	struct xe_tile *tile = arg;
+
+	kobject_put(tile->sysfs);
+}
+
+void xe_tile_sysfs_init(struct xe_tile *tile)
+{
+	struct xe_device *xe = tile_to_xe(tile);
+	struct device *dev = xe->drm.dev;
+	struct kobj_tile *kt;
+	int err;
+
+	kt = kzalloc(sizeof(*kt), GFP_KERNEL);
+	if (!kt)
+		return;
+
+	kobject_init(&kt->base, &xe_tile_sysfs_kobj_type);
+	kt->tile = tile;
+
+	err = kobject_add(&kt->base, &dev->kobj, "tile%d", tile->id);
+	if (err) {
+		kobject_put(&kt->base);
+		drm_warn(&xe->drm, "failed to register TILE sysfs directory, err: %d\n", err);
+		return;
+	}
+
+	tile->sysfs = &kt->base;
+
+	err = drmm_add_action_or_reset(&xe->drm, tile_sysfs_fini, tile);
+	if (err) {
+		drm_warn(&xe->drm, "%s: drmm_add_action_or_reset failed, err: %d\n",
+			 __func__, err);
+		return;
+	}
+}

drivers/gpu/drm/xe/xe_tile_sysfs.h

···
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2023 Intel Corporation
+ */
+
+#ifndef _XE_TILE_SYSFS_H_
+#define _XE_TILE_SYSFS_H_
+
+#include "xe_tile_sysfs_types.h"
+
+void xe_tile_sysfs_init(struct xe_tile *tile);
+
+static inline struct xe_tile *
+kobj_to_tile(struct kobject *kobj)
+{
+	return container_of(kobj, struct kobj_tile, base)->tile;
+}
+
+#endif /* _XE_TILE_SYSFS_H_ */

drivers/gpu/drm/xe/xe_tile_sysfs_types.h

···
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2023 Intel Corporation
+ */
+
+#ifndef _XE_TILE_SYSFS_TYPES_H_
+#define _XE_TILE_SYSFS_TYPES_H_
+
+#include <linux/kobject.h>
+
+struct xe_tile;
+
+/**
+ * struct kobj_tile - A tile's kobject struct that connects the kobject
+ * and the TILE
+ *
+ * When dealing with multiple TILEs, this struct helps to understand which
+ * TILE needs to be addressed on a given sysfs call.
+ */
+struct kobj_tile {
+	/** @base: The actual kobject */
+	struct kobject base;
+	/** @tile: A pointer to the tile itself */
+	struct xe_tile *tile;
+};
+
+#endif	/* _XE_TILE_SYSFS_TYPES_H_ */