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diff --git a/docs/zephyr/project_config.md b/docs/zephyr/project_config.md index f81cc083c9..f930908502 100644 --- a/docs/zephyr/project_config.md +++ b/docs/zephyr/project_config.md @@ -3,174 +3,29 @@ Project Configuration [TOC] -## Overview - -This document defines the organization of the program and project specific files -needed by Zephyr EC projects. - -The goals of the project organization include: - -* Minimize code duplication, allowing multiple projects to share common - configuration options and devicetree nodes. -* Define the set of files required by each project. -* Define the best practices for devicetrees. - - -### Glossary - -- **program**: The name of a Chromebook reference design. The **program** - includes all Chromebooks based on a single AP SoC, such as Intel MeteorLake, - Qualcomm 7c G3, or AMD Mendocino. The **program** corresponds to a single - board overlay in the ChromeOS SDK. The term *baseboard* is often used as a - synonym for **program**. - -- **project**: The name of a specific Chromebook model or variant. All - Chromebook **programs** contain at least one **project** which serves as the - reference design(s) for the **program**. The reference **project** may or may - not use the same name as the **program**. For example, the reference - **project** for the skyrim **program** is also called skyrim. The corsola - **program** included two reference **projects**, kingler and krabby. For the - legacy ECOS builds, *board* was used as a synonym for **project**. - -This document uses bold to highlight the terms **program** and **project** to -reference the definitions above. - -## Directory Structure - -The [`zephyr/program`](../../zephyr/program) contains the **program** and -**project** configuration files for all Zephyr based EC builds. - -### `zephyr/program` directory - -Each **program** has it's own subdirectory under `zephyr/program`. - -``` -zephyr/program/ -├── brya/ -├── corsola/ -├── herobrine/ -├── intelrvp/ -├── it8xxx2_evb/ -├── minimal/ -├── nissa/ -├── npcx_evb/ -├── rex/ -├── skyrim/ -└── trogdor/ -``` - -> The [`zephyr/program/minimal`](../../zephyr/program/minimal/) **program** -contains example EC projects that demonstrate how to build a Zephyr EC with the -minimum feature set enabled. These projects require only a working UART on the -target board. - -### `zephyr/program/`**`<program>`**`/` Directory Overview - -Each **program** subdirectory contains a subdirectory foreach each **project**, -including a subdirectory for the reference **project**. - -The minimum configuration for a **program** named *skyrim* with just a single -reference **project**, also named *skyrim*, is shown below. - -``` -zephyr/program/skyrim/ -├── include/ -│ └── <program headers>.h -├── skyrim/ -│ ├── include/ -│ │ └── <project headers>.h -│ ├── src/ -│ │ └── <project sources>.c -│ ├── CMakeLists.txt -│ ├── project.conf -│ └── project.overlay -├── src/ -│ └── <program sources>.c -├── BUILD.py -├── CMakeLists.txt -├── Kconfig -├── program.conf -└── <devicetrees>.dtsi -``` - -#### `zephyr/program/`**`<program>`**`/` Directory Details - -Description of the files and directories found directly in the **<program>** -level directory. Note that all paths are relative to the `zephyr/program/` -directory. - -- **`<program>`**`/`: Top level directory for the **program**. [skyrim] is the - *program* name in the example above. -- **`<program>`**`/include/`: Directory containing the header files common to - all **projects** in the **program**. Use of **program** level includes is - discouraged. Instead, consider creating a generic driver that can be shared - across all **programs**. -- **`<program>`**`/src/`: Directory containing the C source files common to all - **projects** in the **program**. -- [**`<program>`**`/BUILD.py`](#build_py): Defines which **projects** can be - made from this directory. -- [**`<program>`**`/CMakeLists.txt`](#cmakelists_txt): CMake file for the - **program**. -- [**`<program>`**`/Kconfig`](#kconfig) - Defines new Kconfig options, used by - all **projects** in the **program**. -- [**`<program>`**`/program.conf`](#program_conf) - Sets the default Kconfig - settings for all **projects**. -- **`<program>`**`/<devictrees>.dtsi` - One or more devicetree files, organized - by the hardware module or EC feature. See the [Devicetree Best - Practices](#devicetree-best-practices) section for additional information. -- **`<program>`**`/`**`<project>`**`/`: Top level directory for the - **<project**>. Create a separate directory for each **project** defined by the - **program**. - -### `zephyr/program/`**`<program>`**`/`**`<project>`**`/` Directory Details - -Each **project** provides the following files. Note that all paths are relative -to the `zephyr/program/`**`<program>`**`/` directory. - -- **`<project>`**`/include/`: The **project** may optionally provide a public - include directory, but this is discouraged. There are some exceptions where - the legacy EC code expects the project to define a public header, such as the - keyboard_customization.h file. -- **`<project>`**`/src/`: Directory containing the C source files specific to - the **project**. -- [**`<project>`**`/CMakeLists.txt`](#cmakelists_txt): CMake file for the - **project**. -- [**`<project>`**`/project.conf`](#project_conf): Kconfig settings for the - **project**. -- [**`<project>`**`/project.overlay`](#project_overlay): Main devicetree overlay - for the **project**. - -Creation of custom C source files specific to the **program** or **project** is -discouaraged. You can usually project manage project specific settings with -Kconfig and devicetree changes only. - -Note that **program** and **project** custom C files are still subject to the -same unit test requirements. So all custom C files also require that you write -tests. - -## Setting up a new **program** - -To set up a new EC **program**, create a new directory under -[`zephyr/program`] with the organization shown below. -Note that for this example, the new **program** is called "my_program", and the -reference **project** is called "my_reference_project". - -> Tip - Copy one the **projects** defined by the [*minimal*] **program** to -> start with the bare miminimum of features required to boot the Zephyr EC -> appliation. Then follow the steps in the detailed in [Creating a New Zephyr EC -> Project]. - -``` -zephyr/program/my_program/ -├── my_reference_project/ -│ ├── CMakeLists.txt -│ ├── project.conf -│ └── project.overlay -├── BUILD.py -├── CMakeLists.txt -├── Kconfig -└── program.conf -``` +## Setting up a new program ("reference board" or "baseboard") + +Unlike the legacy EC codebase, Zephyr projects all live together in +one big happy directory. The intent of this design is to encourage +code-sharing between projects, and reduce the amount of copy/paste +that is required to bring up a new project. This directory can, but +does not have to, correlate to the unified build Chrome OS board, +however firmware authors can always choose a different structure if it +makes sense for the specific scenario. As a hypothetical example, +similar Chromeboxes and Chromebooks may wish to share the Zephyr EC +project directory instead of use separate directories, even if they +are using a different unified build board. + +To set up a new EC program, create a new directory under +[`zephyr/projects`](../../zephyr/projects) with the following files: + +- `BUILD.py` - specifies which builds can be made from this directory, + and what the device-tree overlays and Kconfig files are for each + build. +- `CMakeLists.txt` - Baseboard-specific C files can be listed here. +- `prj.conf` (optional) - Default Kconfig settings for all projects. +- `Kconfig` (optional) - Set options for your reference design here, + which variants can use to install optional C sources. An in-depth example of each file is given below: @@ -195,24 +50,18 @@ When `BUILD.py` is sourced, the following two globals are defined: Google codename). This name must be unique amongst all projects known to `zmake`, and `zmake` will error if you choose a conflicting name. -- `zephyr_board` (required): The name of the EC chip used. **Note:** the concept - of a Zephyr board does not align with the ChromeOS concept of a board. The - Zephyr build system requires a set of devicetree and Kconfig files under under - `boards/${ARCH}/${ZEPHYR_BOARD_NAME}`. For the Zephyr EC application, the EC - chip is mapped onto the Zephyr board organization. Supported `zephyr_boards` - include: - - `mec1727`: Microchip MEC1727, 416 KiB RAM, 512 KiB flash - - `npcx7`: Nuvoton NPCX7m7FC, 384 KiB, 512 KiB flash - - `npcx9m3f`: Nuvoton NPCX9m3F, 320 KiB RAM, 512 KiB flash - - `npcx9m7f`: Nuvoton NPCX9m7F, 384 KiB RAM, 1 MiB flash - - `it81202bx`: ITE IT81202, 60 KiB RAM, 1 MiB flash - - `it81302bx`: ITE IT81302, 60 KiB RAM, 1 MiB flash +- `zephyr_board` (required): The name of the Zephyr board to use for + the project. The Zephyr build system expects a Zephyr board + directory under `boards/${ARCH}/${ZEPHYR_BOARD_NAME}`. **Note:** + the concept of a Zephyr board does not align with the Chrome OS + concept of a board: for most projects this will typically be the + name of the EC chip used, not the name of the model or overlay. - `supported_toolchains` (required): A list of the toolchain names - supported by the build. Valid values are: - - `coreboot-sdk`: only supported in the chroot - - `host`: used for unit and integration tests - - `llvm`: only supported in the chroot - - `zephyr`: only supported outside the chroot + supported by the build. Valid values are `coreboot-sdk`, `host`, + `llvm`, and `zephyr`. Note that only `coreboot-sdk` and `llvm` are + supported in the chroot, and all projects must be able to build in + the chroot, so your project must at least list one of `coreboot-sdk` + or `llvm`. - `output_packer` (required): An output packer type which defines which builds get generated, and how they get assembled together into a binary. @@ -228,22 +77,9 @@ When `BUILD.py` is sourced, the following two globals are defined: be used when running the test. Instances of `{test_temp_dir}` inside of an argument will be replaced with a path to a temporary directory guaranteed to be unique for the current execution. -- `dts_overlays` (optional): A list of files which should be concatenated - together and applied as a Zephyr device-tree overlay. The recommended setting - is to select the **project** specific devicetree overlay file. - - ``` python - dts_overlays=[here / project_name / "project.overlay"] - ``` - -- `kconfig_files` (optional): A list of files that contain the Kconfig settings - for the **project**. The recommended setting is select the **program** - configuration file followed by the **project** configuration file. - - ``` python - kconfig_files=[here / "program.conf", here / <project> / "project.conf",] - ``` - +- `dts_overlays` (optional): A list of files which should be + concatenated together and applied as a Zephyr device-tree overlay. + Defaults to no overlays (empty list). - `project_dir` (optional): The path to where `CMakeLists.txt` and `Kconfig` can be found for the project, defaulting to `here`. @@ -277,33 +113,18 @@ This file, should at minimum contain the following: cmake_minimum_required(VERSION 3.20.1) find_package(Zephyr REQUIRED HINTS "${ZEPHYR_BASE}") -project(**project**) -``` - -If your **program** provides any C files, add them to your program CMake file -using `zephyr_library_sources()`. - -``` cmake -zephyr_library_sources("src/my_program_source.c") -``` - -For your **project** C files, create **`<project>/`**`CMakeLists.txt` and use -`add_subdirectory()` to include the **project** CMake file. - -``` cmake -add_subdirectory("my_reference_project") +project(ec) ``` -Add the requires `zephyr_library_souces()` calls to the -**`<project>/`**`CMakeLists.txt` file. +You may additionally want to specify any C files your project needs +using `zephyr_library_sources`. If you need to add extra include +directories, use `cros_ec_library_include_directories`. -If your **program** or **project** provides a public header, make the include -directory visible to rest of the code using -`cros_ec_library_include_directories()`. +### prj.conf and prj_${project_name}.conf -``` cmake -cros_ec_library_include_directories("include") -``` +`prj.conf` has default Kconfig settings for all projects, and +`prj_${project_name}.conf` can contain overrides for certain projects. +The format is `KEY=VALUE`, as typical for Kconfig. ### Kconfig @@ -315,33 +136,6 @@ The file must end with a single line that reads `source "Kconfig.zephyr"`. Note that this file is optional, so it's recommended to only include it if you really need it. -### program.conf - -`program.conf` has default Kconfig settings for all **projects** defined for the -**program**. The format is `KEY=VALUE`, as typical for Kconfig. - -### project.conf - -`project.conf` has the Kconfig settings for a single **project**. The format is -`KEY=VALUE`, as typical for Kconfig. - -Kconfig settings in `project.conf` take precedence over the Kconfig settings -from `program.conf`. - -### project.overlay - -`project.overlay` is the main devicetree overlay for the **project**. The -`project.overlay` contains the following components: -- One or more `#include` statements to add devicetrees defined by the - **program** into project. -- `/delete-node/` statements to remove specific devicetree nodes defined by the - **program** devicetrees. -- New devicetree nodes for **project** specific settings that are not provided - by any **program** devicetrees. - -> Tip: After building your **project**, you can view the final devicetree in the -file `build/zephyr/`**`<project>`**`/build-ro/zephyr/zephyr.dts`. - ## Setting up a new variant of an EC program **Unlike our legacy EC, there are no files or directories to copy and @@ -400,167 +194,3 @@ With this simple variant syntax, lists (like Kconfig files and DTS overlays) are concatenated. This means it's not possible to remove files during variant registration for this syntax, so it's only recommended for the simple case. - -## Devicetree Best Practices - -Below are the best practices for devicetree organization: - -* Split the devicetree across multiple files, organized by the functional block. - This organization applies to the shared **program** devicetrees only. - * FW_CONFIG - * GPIOs - * I2C - * Interrupts - * Keyboard - * LEDs - * Sensors - * Thermal (fans and temperature sensors) - * USB-C -* When creating **program**, usually with a single reference project, add the - shared devicetree files in the program directory, separated by the functional - area noted above. -* Each project creates a `project.overlay` file, and uses `#include` statements - to add shared devicetree files from the program directory. An example - project.overlay for the skyrim project is shown below. - - ``` c - /* Copyright 2021 The ChromiumOS Authors - * Use of this source code is governed by a BSD-style license that can be - * found in the LICENSE file. - */ - - /* Skyrim program common DTS includes */ - #include "../adc.dtsi" - #include "../fan.dtsi" - #include "../gpio.dtsi" - #include "../i2c.dtsi" - #include "../interrupts.dtsi" - #include "../keyboard.dtsi" - #include "../motionsense.dtsi" - #include "../usbc.dtsi" - - /* Skyrim project node overrides */ - /* ... */ - ``` - -### Managing **project** specific settings - -When the **project** needs to make changes to the shared devicetree files, there -are two strategies: - -* For small changes, add the `/delete-node/` attribute to the `project.overlay` - file to remove the specific devices and devicetree nodes from the **project** - final devicetree. -* For larger changes, remove the corresponding `#include` statements from the - `project.overlay` file. Then,dDirectly add any required nodes to the - `project.overlay` file. - -In both cases, the shared devicetree file in the **program** directory is not -changed. - -### Small Devicetree Changes - -Examples of small devicetree changes include: -* Change the I2C peripheral address of a device. -* Changing USB-C related chips. -* Changing motionsense properties, such as the odr and ec-rate properties. -* Overriding a specific property of a node - for instance modifying the - `pinctrl-0` property to adjust the EC pins connected to a device driver. - -The example below demonstrates how to define a device in a **program** -devicetree file and then override the setting in the `project.overlay` file. - -* The herobrine program defines the TCPC at I2C address `0xb` in the file -`zephyr/program/herobrine/i2c.dtsi`. This I2C address is valid for the -herobrine, evoker, and villager projects while the hoglin project needs to -change the I2C address to `0x1b`. - - ``` c - /* zephyr/program/herobrine/i2c.dtsi */ - - &i2c1_0 { - status = "okay"; - /* ... */ - tcpc_port0: ps8xxx@b { - compatible = "parade,ps8xxx"; - reg = <0xb>; - }; - }; - ```` -* The hoglin `project.overlay` file deletes the TCPC node at address `0xb` and -creates a new node at address `0x1b`. The node name “tcpc_port0” is kept the -same, so any references to this node name do not change, such as the USB-C port -configuration. - - ``` c - /* zephyr/program/herobrine/hoglin/project.overlay */ - - #include “../i2c.dtsi” - - &i2c1_0 { - /delete-node/ ps8xxx@b; - tcpc_port0: ps8xxx@1b { - compatible = "parade,ps8xxx"; - reg = <0x1b>; - }; - }; - ``` - -While it is also possible to change a device’s I2C address by directly -overriding the `reg` property, this should not be done. Changing only the `reg` -property causes a mismatch between the node name, `ps8xxx@b`, and the actual -device address, `0x1b`. - -Your `project.overlay` file can also directly override properties defined by the -**program** devicetree files. - -* The skyrim **program** sets the I2C clock frequency for first I2C bus to fast - (400 KHz). - ``` c - /* zephyr/program/skyrim/i2c.dtsi */ - &i2c0_0 { - status = "okay"; - label = "I2C_TCPC0"; - clock-frequency = <I2C_BITRATE_FAST>; - pinctrl-0 = <&i2c0_0_sda_scl_gpb4_b5>; - pinctrl-names = "default"; - }; - ``` -* Override the I2C clock frequency to fast-plus (1 MHz) in the winterhold - `project.overlay`. - ``` c - /* zephyr/program/skyrim/winterhold/project.overlay */ - #include "../i2c.dtsi" - &i2c0_0 { - clock-frequency = <I2C_BITRATE_FAST_PLUS>; - }; - ``` -### Large Devicetree Changes - -For large devicetree changes, the preference is to copy the relevant devicetree -fragment into the `project.overlay` file and edit the fragment directly. - -Examples of large devicetree changes (or changes that don’t benefit from using -the /delete-node/ attribute) include: -* GPIOs - specifically the “named-gpios” node. This integrates better with the - arbitrage and the pinmap utility, which auto-generates the EC GPIO settings - based on schematic data. -* Changes to the motionsense sensor types. Currently x86 architectures impose a - fixed ordering for the accelerometers and gryoscopes when accessed through the - LPC memory map (see the [`EC_MEMMAP_ACC_DATA`]). Deleting nodes changes the - order of the children under the motionsense-sense node and causes the test - [`hardware.SensorAccel`] to fail. Copy the motionsense nodes into the - project.overlay file and modify as required. -* LED policies - generally each OEM/ODM defines unique LED policies for their - designs to establish differentiation for their brand. There is little value to - creating common LED policies for all **projects** in the **program**. -* Batteries - batteries also are generally specific to the OEM/ODM. Define the - **project** batteries directly in the `project.overlay` file. - - -[skyrim]: https://source.chromium.org/chromiumos/chromiumos/codesearch/+/HEAD:src/platform/ec/zephyr/program/skyrim -[`zephyr/program`]: ../../zephyr/program/ -[*minimal*]: ../../zephyr/program/minimal/ -[Creating a New Zephyr EC Project]: ./zephyr_new_board_checklist.md -[`EC_MEMMAP_ACC_DATA`]: https://source.chromium.org/chromiumos/chromiumos/codesearch/+/HEAD:src/platform/ec/include/ec_commands.h;l=181 -[`hardware.SensorAccel`]: https://crsrc.org/o/src/platform/tast-tests/src/chromiumos/tast/local/bundles/cros/hardware/sensor_accel.go;drc=8fbf2c53960bc8917a6a01fda5405cad7c17201e;l=30 |