1.3. Simplified SDK Build Using Top-Level Makefile

1.3.1. Overview

Inside of the Processor SDK Linux AM68A package, there is a top-level Makefile that can be used to build some of the sub-components found within the SDK. This Makefile uses the Rules.make file and gives an example of how the various components can be built and the parameters to use for AM68A.

Note

You should not call this makefile with the environment-setup script sourced. The sub-component Makefiles will handle sourcing this script where appropriate, but some make targets such as the Linux kernel make target do not work properly when this script is already sourced.

Required Host Packages

Please run the top level setup.sh script to install all packages required by the makefile targets.

Components:

The functionality of the Top Level Makefile is implemented by these components:

  • makerules/Makefile_* : These have all of the makerules that are common for TI SDKs across various platforms

  • Rules.make : This defines variables to configure Makefile for Processor SDK Linux AM68A

  • Makefile : Only pulls in these variable definitions and the make rules

Below sections will give a bottoms-up description of these components in some more detail

1.3.1.1. makerules

Target Types

For each of the targets discussed below, the following target types are defined

  • <target> - This is the build target which will compile the release version of the component.

  • <target>_install - This target will install the component to the location pointed to by DESTDIR/BOOTFS

  • <target>_clean - This target will clean the component.

Component Targets

The following is a list of the basic Makefile targets that are provided in the Processor SDK Linux AM68A package as component Makefiles under makerules/ directory:

  • u-boot - This target will build the u-boot binaries for the SOC and SOC_TYPE combination defined in Rules.make. The built binaries will include:

    • tiboot3.bin,

    • tispl.bin,

    • u-boot.img

    Refer to Build U-Boot section for more details on these binaries.

  • linux-dtbs - Compiles and creates the device tree blobs. It uses the KERNEL_DEVICETREE_PREFIX variable defined in Rules.make to parse which dtb[o]s to build.

  • linux - Configures the Linux kernel for TI SOCs and Compiles the following:

    • Image,

    • modules,

    • and dtbs.

    • For SOC_TYPE=hs, This also triggers a build for the linux-fitImage target.

    Refer to Users Guide section for more details on the TI Linux Kernel.

  • linux-fitImage - Picks up images built by ‘u-boot-a72’ and ‘linux’ targets and generates a signed fitImage, u-boot-a72 combination. This is necessary to boot successfully on HS-SE devices (SOC_TYPE=hs), but the fitImage can optionally be authenticated on GP (gp), HS-FS (hs-fs) devices as well by manually setting boot_fit=1 in the u-boot prompt.

    Refer to Creating the kernel fitImage for high security device / GP devices section for more information on the signed linux fitImage.

  • am-benchmarks - Builds the ARM Benchmarks for the ARCH defined in Rules.make.

  • cryptodev - Builds the kernel module for the crypto device driver

  • ti-img-rogue-driver - Builds the Kernel drivers for the PowerVR Rogue GPU

For a full list of supported subcomponent targets, one can also simply run make list-targets at the SDK install location.

1.3.1.2. Rules.make

Here, we cover the Rules.make file found in the top-level of the Processor SDK Linux AM68A package. This file is used not only by the top-level Makefile, but also by many of the sub-component Makefiles to gain access to common shared variables and settings. The variables defined in here are all of the required flags/parameters that will be required to build/compile any of the sub-component makefile targets for AM68A.

Key Variables Defined

Below we describe a subset of the variables defined in the Rules.make that can be editted/overriden by the user as required. These can either be editted into the Rules.make file itself (to reset new defaults) OR can be specified over command line when calling the make command.

  • SOC_TYPE - This describes the HS configuration to build for. It can be set to ‘gp’, ‘hs’, and ‘hs-fs’. It is used when building u-boot and linux to use unsigned or signed images as required.

  • KERNEL_DEVICETREE_PREFIX - This is a regex filter to parse which dtb[o]s should be built for AM68A SOC, when building linux kernel.

  • ROOTFS_PART - This points to the base installation directory that applications/drivers should be installed to. This is usually the root of a target file system but can be changed to point anywhere.

  • BOOT_PART - This points to the base installation directory that u-boot binaries should be installed to. This is usually the boot partition of an SD card but can be changed to point anywhere.

1.3.1.3. Top Level Makefile

Top-Level Targets

The Processor SDK Linux AM68A package provides the following targets by default, which will invoke the corresponding component targets:

  • all - This will call the build target for each component included in the Makefile.

  • install - This will call the install target for each component included in the Makefile.

  • clean - This will call the clean target for each component included in the Makefile.

  • list-targets - This only lists all the supported targets/components for the platform

1.3.2. Usage Examples

The following example demonstrates how to use the top-level Makefile for building and installing u-boot and linux images. All of the examples below assume that you are calling the Makefile from the top-level of the SDK.

  • If using an SD card, edit below variables in the Rules.make to point to the boot and root partitions. Else, point them to directories where you want to install the boot and root-filesystem images respectively.

    BOOT_PART?=/path/to/sd-card/boot-partition
ROOTFS_PART?=/path/to/sd-card/root-partition

  • Set the correct value for the SOC_TYPE variable in Rules.make according to the platform being used.

    SOC_TYPE?=<gp/hs-fs/hs>

  • Now build u-boot, linux kernel images.

    make u-boot
make linux

  • Install to SD card (BOOT_PART & ROOT_PART).

    make u-boot_install
make linux_install

Now you can eject the SD card and boot the devices using the newly built images!

A Note about Out-of-tree Kernel Modules

Some drivers like the GPU drivers are delivered as modules outside of the kernel tree. If you rebuild the kernel and install it using the make linux_install target you will also need to rebuild the out of tree modules and install them as well. The modules_install command used by the linux_install target will remove any existing drivers before installing the new ones. This means those drivers are no longer available until they have been rebuilt against the kernel and re-installed.

A Note about the SOC_TYPE variable

The SOC_TYPE variable serves 2 purposes:

  1. The U-Boot build generates the bootloader images for all 3 SOC types, namely, GP, HS-FS, and HS-SE. These are not compatible with one another. So the SOC_TYPE variable picks up the correct binary accordingly when installing u-boot. For example, below command will install the u-boot images for HS-FS device.

    SOC_TYPE=hs-fs make u-boot
SOC_TYPE=hs-fs make u-boot_install

  2. HS-SE devices enforce fitImage based authentication when booting up. They will fail to boot if (u-boot.img + fitImage) authentication fails. To simplify fitImage generation and testing one can simply set SOC_TYPE=hs when building/installing linux for HS-SE devices.

    SOC_TYPE=hs make linux
SOC_TYPE=hs make linux_install