v4l2-isp.c

  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#include <media/v4l2-isp.h>
 10
 11#include <linux/bitops.h>
 12#include <linux/device.h>
 13
 14#include <media/videobuf2-core.h>
 15
 16int v4l2_isp_params_validate_buffer_size(struct device *dev,
 17					 struct vb2_buffer *vb,
 18					 size_t max_size)
 19{
 20	size_t header_size = offsetof(struct v4l2_isp_params_buffer, data);
 21	size_t payload_size = vb2_get_plane_payload(vb, 0);
 22
 23	/* Payload size can't be greater than the destination buffer size */
 24	if (payload_size > max_size) {
 25		dev_dbg(dev, "Payload size is too large: %zu\n", payload_size);
 26		return -EINVAL;
 27	}
 28
 29	/* Payload size can't be smaller than the header size */
 30	if (payload_size < header_size) {
 31		dev_dbg(dev, "Payload size is too small: %zu\n", payload_size);
 32		return -EINVAL;
 33	}
 34
 35	return 0;
 36}
 37EXPORT_SYMBOL_GPL(v4l2_isp_params_validate_buffer_size);
 38
 39int v4l2_isp_params_validate_buffer(struct device *dev, struct vb2_buffer *vb,
 40				    const struct v4l2_isp_params_buffer *buffer,
 41				    const struct v4l2_isp_params_block_type_info *type_info,
 42				    size_t num_block_types)
 43{
 44	size_t header_size = offsetof(struct v4l2_isp_params_buffer, data);
 45	size_t payload_size = vb2_get_plane_payload(vb, 0);
 46	size_t block_offset = 0;
 47	size_t buffer_size;
 48
 49	/*
 50	 * Currently only the first version of the V4L2 ISP parameters format is
 51	 * supported. We accept both V0 and V1 to support existing drivers
 52	 * compatible with V4L2 ISP that use either 0 or 1 as their "first
 53	 * version" identifiers.
 54	 */
 55	if (buffer->version != V4L2_ISP_PARAMS_VERSION_V0 &&
 56	    buffer->version != V4L2_ISP_PARAMS_VERSION_V1) {
 57		dev_dbg(dev,
 58			"Unsupported V4L2 ISP parameters format version: %u\n",
 59			buffer->version);
 60		return -EINVAL;
 61	}
 62
 63	/* Validate the size reported in the header */
 64	buffer_size = header_size + buffer->data_size;
 65	if (buffer_size != payload_size) {
 66		dev_dbg(dev, "Data size %zu and payload size %zu are different\n",
 67			buffer_size, payload_size);
 68		return -EINVAL;
 69	}
 70
 71	/* Walk the list of ISP configuration blocks and validate them. */
 72	buffer_size = buffer->data_size;
 73	while (buffer_size >= sizeof(struct v4l2_isp_params_block_header)) {
 74		const struct v4l2_isp_params_block_type_info *info;
 75		const struct v4l2_isp_params_block_header *block;
 76
 77		block = (const struct v4l2_isp_params_block_header *)
 78			(buffer->data + block_offset);
 79
 80		if (block->type >= num_block_types) {
 81			dev_dbg(dev,
 82				"Invalid block type %u at offset %zu\n",
 83				block->type, block_offset);
 84			return -EINVAL;
 85		}
 86
 87		if (block->size > buffer_size) {
 88			dev_dbg(dev, "Premature end of parameters data\n");
 89			return -EINVAL;
 90		}
 91
 92		/* It's invalid to specify both ENABLE and DISABLE. */
 93		if ((block->flags & (V4L2_ISP_PARAMS_FL_BLOCK_ENABLE |
 94				     V4L2_ISP_PARAMS_FL_BLOCK_DISABLE)) ==
 95		     (V4L2_ISP_PARAMS_FL_BLOCK_ENABLE |
 96		     V4L2_ISP_PARAMS_FL_BLOCK_DISABLE)) {
 97			dev_dbg(dev, "Invalid block flags %x at offset %zu\n",
 98				block->flags, block_offset);
 99			return -EINVAL;
100		}
101
102		/*
103		 * Match the block reported size against the type info provided
104		 * one, but allow the block to only contain the header in
105		 * case it is going to be disabled.
106		 */
107		info = &type_info[block->type];
108		if (block->size != info->size &&
109		    (!(block->flags & V4L2_ISP_PARAMS_FL_BLOCK_DISABLE) ||
110		    block->size != sizeof(*block))) {
111			dev_dbg(dev,
112				"Invalid block size %u (expected %zu) at offset %zu\n",
113				block->size, info->size, block_offset);
114			return -EINVAL;
115		}
116
117		block_offset += block->size;
118		buffer_size -= block->size;
119	}
120
121	if (buffer_size) {
122		dev_dbg(dev, "Unexpected data after the parameters buffer end\n");
123		return -EINVAL;
124	}
125
126	return 0;
127}
128EXPORT_SYMBOL_GPL(v4l2_isp_params_validate_buffer);
129
130MODULE_LICENSE("GPL");
131MODULE_AUTHOR("Jacopo Mondi <jacopo.mondi@ideasonboard.com");
132MODULE_DESCRIPTION("V4L2 generic ISP parameters and statistics helpers");