[PATCH v6 3/4] media: uapi: mediatek: Add MT8188 AIE control definitions

[Sarang Chaudhari <sarang.chaudhari@mediatek.com>]

Add AIE (AI Engine) UAPI control definitions and register the
V4L2_META_FMT_MTFD_RESULT metadata format for the MediaTek face
detection hardware accelerator.

This patch adds:
- include/uapi/linux/mtk_aie_v4l2_controls.h: Custom V4L2 control IDs
  for AIE initialization and per-frame parameters.
- V4L2_META_FMT_MTFD_RESULT format in videodev2.h for face detection
  result metadata output.
- Format description in v4l2-ioctl.c.

Signed-off-by: Sarang Chaudhari <sarang.chaudhari@mediatek.com>
---
Changes in v6:
- Simplify UAPI header to contain only control ID definitions. Full
  structures kept in kernel-internal header for now, pending UAPI
  structure redesign per CK Hu's feedback.
- Drop V4L2_CTRL_TYPE_AIE_INIT and V4L2_CTRL_TYPE_AIE_PARAM from
  v4l2_ctrl_type enum (use V4L2_CTRL_TYPE_U32 compound control instead).
- Address CK Hu's review feedback: remove freq_level, improve
  feature_threshold docs, clarify pyramid multi-scale detection, clarify
  FLD mode uses FD results via Binary Tree Traversal.

Changes in v5:
- Add an introduction for feature_threshold.
- Rename v4l2_aie_roi to aie_roi_coordinate.
- Rename v4l2_aie_padding to aie_padding_size.
- Explain en_padding and the three modes of fd_mode.
- Move structures from mtk_aie.h to the uapi directory.

Changes in v4:
- Document the detail of V4L2_META_FMT_MTFD_RESULT.
- Add the introduction of related variables.

Changes in v3: None

Changes in v2:
- Fix coding style.

 drivers/media/v4l2-core/v4l2-ioctl.c       |  1 +
 include/uapi/linux/mtk_aie_v4l2_controls.h | 23 ++++++++++++++++++++++
 include/uapi/linux/videodev2.h             |  1 +
 3 files changed, 25 insertions(+)
 create mode 100644 include/uapi/linux/mtk_aie_v4l2_controls.h

diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
index e50e517..8754098 100644
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -11,6 +11,7 @@ static void v4l_fill_fmtdesc(struct v4l2_fmtdesc *fmt)
 	case V4L2_META_FMT_GENERIC_CSI2_16:	descr = "8-bit Generic Meta, 16b CSI-2"; break;
 	case V4L2_META_FMT_GENERIC_CSI2_20:	descr = "8-bit Generic Meta, 20b CSI-2"; break;
 	case V4L2_META_FMT_GENERIC_CSI2_24:	descr = "8-bit Generic Meta, 24b CSI-2"; break;
+	case V4L2_META_FMT_MTFD_RESULT:	descr = "Mediatek Face Detect Result"; break;
 
 	default:
 		/* Compressed formats */
diff --git a/include/uapi/linux/mtk_aie_v4l2_controls.h b/include/uapi/linux/mtk_aie_v4l2_controls.h
new file mode 100644
index 0000000..a8b2927
--- /dev/null
+++ b/include/uapi/linux/mtk_aie_v4l2_controls.h
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+ * MediaTek AI Engine (AIE) V4L2 control definitions
+ *
+ * Copyright (c) 2020 MediaTek Inc.
+ * Author: Fish Wu <fish.wu@mediatek.com>
+ */
+
+#ifndef __UAPI_MTK_AIE_V4L2_CONTROLS_H__
+#define __UAPI_MTK_AIE_V4L2_CONTROLS_H__
+
+#include <linux/videodev2.h>
+
+/*
+ * The base for the MediaTek AIE driver controls.
+ * We reserve 16 controls for this driver.
+ */
+#define V4L2_CID_USER_MTK_FD_BASE	(V4L2_CID_USER_BASE + 0x1fd0)
+
+#define V4L2_CID_MTK_AIE_INIT		(V4L2_CID_USER_MTK_FD_BASE + 1)
+#define V4L2_CID_MTK_AIE_PARAM		(V4L2_CID_USER_MTK_FD_BASE + 2)
+
+#endif /* __UAPI_MTK_AIE_V4L2_CONTROLS_H__ */
diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index 7668201..6d6866d 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -10,6 +10,7 @@ struct v4l2_pix_format {
 #define V4L2_META_FMT_GENERIC_CSI2_16	v4l2_fourcc('M', 'C', '1', 'G') /* 16-bit CSI-2 packed 8-bit metadata */
 #define V4L2_META_FMT_GENERIC_CSI2_20	v4l2_fourcc('M', 'C', '1', 'K') /* 20-bit CSI-2 packed 8-bit metadata */
 #define V4L2_META_FMT_GENERIC_CSI2_24	v4l2_fourcc('M', 'C', '1', 'O') /* 24-bit CSI-2 packed 8-bit metadata */
+#define V4L2_META_FMT_MTFD_RESULT	v4l2_fourcc('M', 'T', 'f', 'd') /* Mediatek face detection result */
 #endif
 
 /* priv field value to indicates that subsequent fields are valid. */
-- 
2.45.2