media: mediatek: vcodec: Add debugfs interface to get debug information

This will be useful when debugging specific issues related to kernel
in running status.

Signed-off-by: Yunfei Dong <yunfei.dong@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

Author: yunfei-mtk

drivers/media/platform/mediatek/vcodec/Makefile

@@ -46,3 +46,9 @@ endif
 ifneq ($(CONFIG_VIDEO_MEDIATEK_VCODEC_SCP),)
 mtk-vcodec-common-y += mtk_vcodec_fw_scp.o
 endif
+
+ifneq ($(CONFIG_DEBUG_FS),)
+obj-$(CONFIG_VIDEO_MEDIATEK_VCODEC) += mtk-vcodec-dbgfs.o
+
+mtk-vcodec-dbgfs-y := mtk_vcodec_dbgfs.o
+endif

drivers/media/platform/mediatek/vcodec/mtk_vcodec_dbgfs.c

@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2023 MediaTek Inc.
+ * Author: Yunfei Dong <yunfei.dong@mediatek.com>
+ */
+
+#include <linux/debugfs.h>
+
+#include "mtk_vcodec_dbgfs.h"
+#include "mtk_vcodec_drv.h"
+#include "mtk_vcodec_util.h"
+
+void mtk_vcodec_dbgfs_init(struct mtk_vcodec_dev *vcodec_dev)
+{
+	struct dentry *vcodec_root;
+
+	vcodec_dev->dbgfs.vcodec_root = debugfs_create_dir("vcodec-dec", NULL);
+	if (IS_ERR(vcodec_dev->dbgfs.vcodec_root))
+		dev_err(&vcodec_dev->plat_dev->dev, "create vcodec dir err:%d\n",
+			IS_ERR(vcodec_dev->dbgfs.vcodec_root));
+
+	vcodec_root = vcodec_dev->dbgfs.vcodec_root;
+}
+EXPORT_SYMBOL_GPL(mtk_vcodec_dbgfs_init);
+
+void mtk_vcodec_dbgfs_deinit(struct mtk_vcodec_dev *vcodec_dev)
+{
+	debugfs_remove_recursive(vcodec_dev->dbgfs.vcodec_root);
+}
+EXPORT_SYMBOL_GPL(mtk_vcodec_dbgfs_deinit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Mediatek video codec driver");

drivers/media/platform/mediatek/vcodec/mtk_vcodec_dbgfs.h

@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2023 MediaTek Inc.
+ * Author: Yunfei Dong <yunfei.dong@mediatek.com>
+ */
+
+#ifndef __MTK_VCODEC_DBGFS_H__
+#define __MTK_VCODEC_DBGFS_H__
+
+struct mtk_vcodec_dev;
+
+/**
+ * struct mtk_vcodec_dbgfs  - dbgfs information
+ * @vcodec_root: vcodec dbgfs entry
+ */
+struct mtk_vcodec_dbgfs {
+	struct dentry *vcodec_root;
+};
+
+#if defined(CONFIG_DEBUG_FS)
+void mtk_vcodec_dbgfs_init(struct mtk_vcodec_dev *vcodec_dev);
+void mtk_vcodec_dbgfs_deinit(struct mtk_vcodec_dev *vcodec_dev);
+#else
+static inline void mtk_vcodec_dbgfs_init(struct mtk_vcodec_dev *vcodec_dev)
+{
+}
+
+static inline void mtk_vcodec_dbgfs_deinit(struct mtk_vcodec_dev *vcodec_dev)
+{
+}
+#endif
+#endif

drivers/media/platform/mediatek/vcodec/mtk_vcodec_dec_drv.c

@@ -422,6 +422,7 @@ static int mtk_vcodec_probe(struct platform_device *pdev)
 		mtk_v4l2_debug(0, "media registered as /dev/media%d", vfd_dec->minor);
 	}
 
+	mtk_vcodec_dbgfs_init(dev);
 	mtk_v4l2_debug(0, "decoder registered as /dev/video%d", vfd_dec->minor);
 
 	return 0;
@@ -497,6 +498,7 @@ static void mtk_vcodec_dec_remove(struct platform_device *pdev)
 	if (dev->vfd_dec)
 		video_unregister_device(dev->vfd_dec);
 
+	mtk_vcodec_dbgfs_deinit(dev);
 	v4l2_device_unregister(&dev->v4l2_dev);
 	if (!dev->vdec_pdata->is_subdev_supported)
 		pm_runtime_disable(dev->pm.dev);

drivers/media/platform/mediatek/vcodec/mtk_vcodec_drv.h

@@ -16,6 +16,7 @@
 #include <media/v4l2-mem2mem.h>
 #include <media/videobuf2-core.h>
 
+#include "mtk_vcodec_dbgfs.h"
 #include "mtk_vcodec_util.h"
 #include "vdec_msg_queue.h"
 
@@ -471,6 +472,7 @@ struct mtk_vcodec_enc_pdata {
  * @dec_active_cnt: used to mark whether need to record register value
  * @vdec_racing_info: record register value
  * @dec_racing_info_mutex: mutex lock used for inner racing mode
+ * @dbgfs: debug log related information
  */
 struct mtk_vcodec_dev {
 	struct v4l2_device v4l2_dev;
@@ -520,6 +522,8 @@ struct mtk_vcodec_dev {
 	u32 vdec_racing_info[132];
 	/* Protects access to vdec_racing_info data */
 	struct mutex dec_racing_info_mutex;
+
+	struct mtk_vcodec_dbgfs dbgfs;
 };
 
 static inline struct mtk_vcodec_ctx *fh_to_ctx(struct v4l2_fh *fh)