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doc: hpf and softperipherals comparison
added a guide comparing softperipherals and hpf solutions Signed-off-by: Anna Wojdylo <[email protected]>
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‎doc/nrf/app_dev/device_guides/coprocessors/index.rst

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The High-Performance Framework (HPF) support in the |NCS| is :ref:`experimental <software_maturity>` and is limited to the nRF54L15 device.
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The following pages provide a detailed guide on utilizing coprocessor effectively within the nRF54L15 platform.
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You can use the VPR coprocessor (Fast Lightweight Peripheral Processor - FLPR) as follows:
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The VPR coprocessor (Fast Lightweight Peripheral Processor - FLPR) can be utilized in two distinct ways:
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* As an additional core in a multicore system using Zephyr in multithreaded mode (see the :ref:`nRF54L15<vpr_flpr_nrf54l>` and :ref:`nRF54H20 devices<ug_nrf54h20_flpr>` pages).
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* As a peripheral emulator, using one of the following methods depending on the use case:
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* As an additional core in a multicore system using Zephyr in multithreaded mode.
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See :ref:`vpr_flpr_nrf54l` for more details.
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* As a peripheral emulator using the High-Performance Framework (HPF).
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For more information, refer to the following documentation.
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* :ref:`High-Performance Framework (HPF)<hpf_index>`
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* :ref:`nrfxlib:soft_peripherals`
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.. note::
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In these usage modes, it is important to clearly differentiate between the Soft Peripheral and HPF solutions.
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Soft Peripherals serve as a direct replacement for hardware peripherals, offering guaranteed performance.
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In contrast, the HPF will allow you to accelerate protocol operations, but performance depends on your implementation.
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We recommend using the Soft Peripheral solution if it meets your product's requirements.
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The following table outlines the main differences between the usage modes.
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For detailed comparison see the :ref:`ug_hpf_softperipherals_comparison` page.
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.. list-table:: Main differences between usage modes
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:header-rows: 1
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* - Comparison category
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- Zephyr
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- HPF
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- Soft Peripherals
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* - Overview
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- Comprehensive Zephyr application with full feature access.
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- Bare-metal build from source featuring real-time I/O capabilities.
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- Custom binary that emulates a hardware peripheral.
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* - Advantages
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- Full access to Zephyr's capabilities including drivers, libraries, and OS primitives.
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- Enables custom protocol support with optimized execution latency and minimized code footprint.
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- - Pre-validated product, fully compliant with the simulated hardware peripheral specifications.
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- Compatible with higher layer driver.
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* - Limitations
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- Larger code size and higher execution latency.
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- Requires development of custom code.
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- Provided as a binary making modifications impossible.
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* - Build system
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- Built from source using Zephyr’s sysbuild.
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- Built from source using Zephyr’s sysbuild.
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- Custom HEX file loaded by the application core.
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VPR is exposed to build system.
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Only the GPIO ports and pins utilized by the VPR are configured within an overlay.
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* - Inter-processor communication
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- Zephyr’s IPC service or mbox API.
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- Zephyr’s IPC service or mbox API.
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- Managed through the peripheral driver API.
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* - Work offloading
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- Supports any task, including those requiring Zephyr libraries.
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- Handles simple data pre-processing or post-processing based on specific protocol needs.
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- Not supported.
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* - Maturity level
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- Experimental (nRF54L15 and nRF54H20)
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- Experimental (nRF54L15)
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- Supported (see :ref:`nrfxlib:soft_peripherals` documentation for the list of supported devices)
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* - Example use case
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- Utilizes VPR as a standard CPU and offloads tasks to VPR.
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- Develops custom protocol emulators.
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- Replaces conventional hardware peripherals.
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.. toctree::
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:maxdepth: 1
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:caption: Contents
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ug_hpf_softperipherals_comparison.rst
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hpf.rst

‎doc/nrf/app_dev/device_guides/coprocessors/ug_hpf_softperipherals_comparison.rst

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.. _ug_hpf_softperipherals_comparison:
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Introduction to Soft Peripherals and High-Performance Framework
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###############################################################
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.. contents::
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:local:
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:depth: 2
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:ref:`nrfxlib:soft_peripherals` are a collection of pre-compiled binaries and API driver code designed to emulate commonly used peripherals.
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These peripherals allow application code to use the API driver to load the pre-compiled binaries onto a specific RAM location, where they are executed by the RISC-V coprocessor, named Fast Lightweight Peripheral Processor (FLPR) (see the :ref:`nRF54L15<vpr_flpr_nrf54l>` and :ref:`nRF54H20 devices<ug_nrf54h20_flpr>` pages).
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The application can then control the soft peripherals using API functions.
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The :ref:`High-Performance Framework (HPF)<hpf_index>` is a framework designed to support the development and integration of software peripherals using coprocessors.
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It offers tools such as Hardware Abstraction Layers (HALs) and CMake targets, along with application samples and guidelines on architectural issues like event, fault, and power management.
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These resources will help you create customized software peripherals tailored to specific application needs.
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Design rationale and usage
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**************************
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Both methods facilitate the creation of software-defined peripherals that emulate the functionality of physical hardware peripherals (IP) through software.
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Choosing between the solutions depends on the specific requirements of your project and the resources available.
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.. _nrf54l_hpf_softperi_comparison_use_case:
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Implementation and use cases
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============================
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The following comparison details implementation and typical use cases for Soft Peripherals and High Performance Framework:
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.. list-table::
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:header-rows: 1
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* - Comparison aspect
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- Soft Peripherals
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- High Performance Framework
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* - Development
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- Optimized for performance and power consumption.
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- Allows for the creation of specialized or custom peripherals.
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* - Use cases
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- - When an application requires an additional or unavailable peripheral and a corresponding Soft Peripheral is available.
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- Suitable for applications built from pre-compiled sources.
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- - When developing a custom peripheral or when high-degree control is needed.
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- Enhances the main processor's functionality with real-time capabilities in a streamlined, bare metal environment.
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- Integrated with the Zephyr build system.
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- Ideal for applications where the FLPR handles higher layers of the software stack (it allows to offload parts of the protocol stack to the FLPR core).
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.. _nrf54l_hpf_softperi_comparison_features:
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Features comparison
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===================
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See the following detailed feature comparison between Soft Peripherals and High-Performance Framework:
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.. list-table::
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:header-rows: 1
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* - Feature
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- Soft Peripherals
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- High Performance Framework
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* - Integration
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- Pre-compiled binary for FLPR, driver for the application core
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- Built from source in Zephyr build system
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* - Memory requirements
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- Fixed (~16 K)
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- Adjustable, depends on code and devicetree
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* - Application compatibility
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- Can be used on baremetal or Zephyr applications
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- Uses Zephyr without kernel on FLPR side, full Zephyr on APP side
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* - Integration complexity
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- Minor integration required
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- Samples provided for the start of development
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* - IPC mechanism
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- Register-based
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- ic(b)msg or mbox-based
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* - Compliance and testing
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- Protocol-compliant, verified by Nordic Semiconductor
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- Samples provided as-is, testing is done by the user
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* - Delivery form
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- Binary
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- Source code, modifiable and extendable
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* - API level
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- Exposed at hardware driver level
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- FLPR may handle parts of the software stack above hardware driver level
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.. _nrf54l_hpf_softperi_comparison_requirements:
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Requirements
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************
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For Soft Peripherals, there is a specific memory size requirement of approximately 16 K, but there is a flexibility in placement within the FLPR execution RAM.
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To enter low power consumption modes, Soft Peripherals require a slot at a specific memory address, which is platform-specific, and the application code must be able to access MEMCONF registers.
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See the requirements in the :ref:`Soft Peripherals section<nrfxlib:soft_peripherals>`.
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It provides essential information for proper integration and optimization.
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On the other hand, HPF necessitates that the application core uses the Zephyr operating system.
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The framework allows for a high degree of configurability, which you can tailor according to your needs using Kconfig and devicetree settings.
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This allows you to optimize the memory footprint and functionality of the custom peripherals, ensuring that the peripherals are well-integrated and perform efficiently within their specific application environments.
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.. _nrf54l_hpf_softperi_comparison_creating_peripherals:
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Creation of software-defined peripherals
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****************************************
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For Soft Peripherals, the integration process primarily involves incorporating glue code to facilitate their use.
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To learn how to use those peripherals, and to see what is currently supported, refer to the :ref:`nrfxlib:soft_peripherals` documentation.
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In contrast, HPF provides initial samples that serve as a starting point for development.
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For a detailed guide on creating your own custom peripherals, see the :ref:`hpf_index` page.
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.. _nrf54l_hpf_softperi_comparison_limitations:
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Performance and limitations
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***************************
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Each Soft Peripheral is unique and comes with its own set of limitations compared to traditional hardware IP.
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These limitations are specific to the functions that the peripheral is designed to emulate and how they integrate with the rest of the system.
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HPF, while offering extensive customization and control, is currently in an experimental stage and lacks full power management support.

‎doc/nrf/app_dev/device_guides/nrf54h/ug_nrf54h20_flpr.rst

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When building for the ``nrf54h20dk/nrf54h20/cpuflpr`` target, a minimal sample is automatically loaded onto the application core.
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For more details, see :ref:`building_nrf54h_app_flpr_core`.
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Peripherals emulation on FLPR
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*****************************
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The FLPR core can emulate software-defined peripherals using :ref:`nrfxlib:soft_peripherals`.
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This setup is useful in scenarios where you need an additional peripheral functionality but do not have access to hardware peripherals.
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Memory allocation
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*****************
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‎doc/nrf/app_dev/device_guides/nrf54l/vpr_flpr.rst

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When building for the ``nrf54l15dk/nrf54l15/cpuflpr`` target, a minimal sample is automatically loaded onto the application core.
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See more information on :ref:`building_nrf54l_app_flpr_core`.
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Using MCUboot with FLPR
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***********************
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Peripherals emulation on FLPR
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*****************************
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.. note::
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The High-Performance Framework (HPF) support in the |NCS| is :ref:`experimental <software_maturity>` and is limited to the nRF54L15 device.
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The FLPR core can emulate software peripherals using :ref:`nrfxlib:soft_peripherals` or the :ref:`HPF<hpf_index>`.
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This setup is useful in scenarios where you need additional peripheral functionality or want to optimize power consumption and performance.
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For detailed comparisons of implementation scenarios and use cases between the Soft Peripherals and the HPF, refer to the :ref:`ug_hpf_softperipherals_comparison` documentation page.
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MCUboot FLPR configuration
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**************************
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To ensure that MCUboot functions correctly with a FLPR-integrated application, several manual configurations are necessary.
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For details, see :ref:`nRF54l_signing_app_with_flpr_payload`.

‎doc/nrf/releases_and_maturity/releases/release-notes-changelog.rst

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Developing with coprocessors
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============================
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* Added the :ref:`ug_hpf_softperipherals_comparison` documentation page, describing potential use cases and differences between the two solutions.
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