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1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 * Video4Linux2 generic ISP parameters and statistics support
4 *
5 * Copyright (C) 2025 Ideas On Board Oy
6 * Author: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
7 */
8
9#ifndef _V4L2_ISP_H_
10#define _V4L2_ISP_H_
11
12#include <linux/media/v4l2-isp.h>
13
14struct device;
15struct vb2_buffer;
16
17/**
18 * v4l2_isp_params_buffer_size - Calculate size of v4l2_isp_params_buffer
19 * @max_params_size: The total size of the ISP configuration blocks
20 *
21 * Users of the v4l2 extensible parameters will have differing sized data arrays
22 * depending on their specific parameter buffers. Drivers and userspace will
23 * need to be able to calculate the appropriate size of the struct to
24 * accommodate all ISP configuration blocks provided by the platform.
25 * This macro provides a convenient tool for the calculation.
26 */
27#define v4l2_isp_params_buffer_size(max_params_size) \
28 (offsetof(struct v4l2_isp_params_buffer, data) + (max_params_size))
29
30/**
31 * v4l2_isp_params_validate_buffer_size - Validate a V4L2 ISP buffer sizes
32 * @dev: the driver's device pointer
33 * @vb: the videobuf2 buffer
34 * @max_size: the maximum allowed buffer size
35 *
36 * This function performs validation of the size of a V4L2 ISP parameters buffer
37 * before the driver can access the actual data buffer content.
38 *
39 * After the sizes validation, drivers should copy the buffer content to a
40 * kernel-only memory area to prevent userspace from modifying it,
41 * before completing validation using v4l2_isp_params_validate_buffer().
42 *
43 * The @vb buffer as received from the vb2 .buf_prepare() operation is checked
44 * against @max_size and it's validated to be large enough to accommodate at
45 * least one ISP configuration block.
46 */
47int v4l2_isp_params_validate_buffer_size(struct device *dev,
48 struct vb2_buffer *vb,
49 size_t max_size);
50
51/**
52 * struct v4l2_isp_params_block_type_info - V4L2 ISP per-block-type info
53 * @size: the block type expected size
54 *
55 * The v4l2_isp_params_block_type_info collects information of the ISP
56 * configuration block types for validation purposes. It currently only contains
57 * the expected block type size.
58 *
59 * Drivers shall prepare a list of block type info, indexed by block type, one
60 * for each supported ISP block type and correctly populate them with the
61 * expected block type size.
62 */
63struct v4l2_isp_params_block_type_info {
64 size_t size;
65};
66
67/**
68 * v4l2_isp_params_validate_buffer - Validate a V4L2 ISP parameters buffer
69 * @dev: the driver's device pointer
70 * @vb: the videobuf2 buffer
71 * @buffer: the V4L2 ISP parameters buffer
72 * @type_info: the array of per-block-type validation info
73 * @num_block_types: the number of block types in the type_info array
74 *
75 * This function completes the validation of a V4L2 ISP parameters buffer,
76 * verifying each configuration block correctness before the driver can use
77 * them to program the hardware.
78 *
79 * Drivers should use this function after having validated the correctness of
80 * the vb2 buffer sizes by using the v4l2_isp_params_validate_buffer_size()
81 * helper first. Once the buffer size has been validated, drivers should
82 * perform a copy of the user provided buffer into a kernel-only memory buffer
83 * to prevent userspace from modifying its content after it has been submitted
84 * to the driver, and then call this function to complete validation.
85 */
86int v4l2_isp_params_validate_buffer(struct device *dev, struct vb2_buffer *vb,
87 const struct v4l2_isp_params_buffer *buffer,
88 const struct v4l2_isp_params_block_type_info *type_info,
89 size_t num_block_types);
90
91#endif /* _V4L2_ISP_H_ */