v4l2_params.h

/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2025, Ideas On Board
 *
 * V4L2 ISP Parameters
 */
 
#pragma once
 
#include <map>
#include <stdint.h>
#include <string.h>
 
#include <linux/media/v4l2-isp.h>
 
#include <libcamera/base/log.h>
#include <libcamera/base/span.h>
#include <libcamera/base/utils.h>
 
namespace libcamera {
 
namespace ipa {
 
LOG_DECLARE_CATEGORY(V4L2Params)
 
template<typename T>
class V4L2ParamsBlock
{
public:
    V4L2ParamsBlock(const Span<uint8_t> data)
        : data_(data)
    {
    }
 
    virtual ~V4L2ParamsBlock() {}
 
    virtual void setEnabled(bool enabled)
    {
        struct v4l2_isp_params_block_header *header =
            reinterpret_cast<struct v4l2_isp_params_block_header *>(data_.data());
 
        header->flags &= ~(V4L2_ISP_PARAMS_FL_BLOCK_ENABLE |
                   V4L2_ISP_PARAMS_FL_BLOCK_DISABLE);
        header->flags |= enabled ? V4L2_ISP_PARAMS_FL_BLOCK_ENABLE
                     : V4L2_ISP_PARAMS_FL_BLOCK_DISABLE;
    }
 
    virtual const T *operator->() const
    {
        return reinterpret_cast<const T *>(data_.data());
    }
 
    virtual T *operator->()
    {
        return reinterpret_cast<T *>(data_.data());
    }
 
    virtual const T &operator*() const
    {
        return *reinterpret_cast<const T *>(data_.data());
    }
 
    virtual T &operator*()
    {
        return *reinterpret_cast<T *>(data_.data());
    }
 
protected:
    Span<uint8_t> data_;
};
 
class V4L2ParamsBase
{
protected:
    V4L2ParamsBase(Span<uint8_t> data, unsigned int version);
 
public:
    size_t bytesused() const { return used_; }
 
protected:
    Span<uint8_t> block(uint16_t type, unsigned int blockType,
                size_t blockSize);
 
    Span<uint8_t> data_;
    size_t used_;
 
    std::map<uint16_t, Span<uint8_t>> blocks_;
};
 
template<typename Traits>
class V4L2Params : public V4L2ParamsBase
{
public:
    static_assert(std::is_same_v<std::underlying_type_t<typename Traits::id_type>, uint16_t>);
 
    V4L2Params(Span<uint8_t> data, unsigned int version)
        : V4L2ParamsBase(data, version)
    {
    }
 
    template<typename Traits::id_type Id>
    auto block()
    {
        using Details = typename Traits::template id_to_details<Id>;
 
        using Type = typename Details::type;
        constexpr auto kernelId = Details::blockType;
 
        auto data = V4L2ParamsBase::block(utils::to_underlying(Id),
                          kernelId, sizeof(Type));
        return V4L2ParamsBlock<Type>(data);
    }
};
 
} /* namespace ipa */
 
} /* namespace libcamera */