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[[Category:SDK]] | [[Category:SDK]] | ||
{{PublicationRequestId | 7646 | 2018-06-04 | PhilipS}} | |||
==Article purpose== | ==Article purpose== | ||
The pieces of software delivered as source code within the OpenSTLinux Developer Package (for example the Linux kernel) can be modified. External out-of-tree Linux kernel modules, and pieces of applicative software (for example Linux applications) can also be developed thanks to this Developer Package, and loaded onto the board. | The pieces of software delivered as source code within the OpenSTLinux Developer Package (for example the Linux kernel) can be modified. External out-of-tree Linux kernel modules, and pieces of applicative software (for example Linux applications) can also be developed thanks to this Developer Package, and loaded onto the board. | ||
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There are different ways to use the SDK toolchain directly, among which Makefile and Autotools. <br> | There are different ways to use the SDK toolchain directly, among which Makefile and Autotools. <br> | ||
Whatever the method, it relies on: | Whatever the method, it relies on: | ||
* the sysroot that is associated with the cross-toolchain, and that contains the header files and libraries needed for generating binaries (see [[SDK for OpenSTLinux distribution# | * the sysroot that is associated with the cross-toolchain, and that contains the header files and libraries needed for generating binaries (see [[SDK for OpenSTLinux distribution#Native and target sysroots|target sysroot]]) | ||
* the environment variables created by the SDK environment setup script (see [[SDK for OpenSTLinux distribution# | * the environment variables created by the SDK environment setup script (see [[SDK for OpenSTLinux distribution#SDK startup|SDK startup]]) | ||
You can refer to the following simple example: | You can refer to the following simple example: | ||
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You can refer to the following simple example: | You can refer to the following simple example: | ||
* [[How to cross-compile with the Developer Package#Modifying the TF-A|Modification of the TF-A]] | * [[How to cross-compile with the Developer Package#Modifying the TF-A|Modification of the TF-A]] | ||
===Modifying the OP-TEE=== | |||
Prerequisites: | |||
* the [[STM32MP1 Developer Package#Installing the SDK|SDK is installed]] | |||
* the [[STM32MP1 Developer Package#Starting up the SDK|SDK is started up]] | |||
* the [[STM32MP1 Developer Package#Installing the OP-TEE|OP-TEE is installed]] | |||
{{highlight|'''The ''<OP-TEE installation directory>/README.HOW_TO.txt'' helper file gives the commands to:'''}} <br> | |||
<span style="font-size:21px">☐</span> cross-compile the OP-TEE <br> | |||
<span style="font-size:21px">☐</span> deploy the OP-TEE (that is, update the software on board) <br> | |||
{{ReviewsComments|YCO 15-Feb-19 : link missing "Modification of the OP-TEE"<br> | |||
There is no link because the page "How_to_cross-compile_with_the_Developer_Package" doesn't contain a paragraph for TEE, <br> | |||
SO THIS PARAGRAH "Modifying the OP-TEE" is not useful, it gives no more informations.<br> | |||
The paragraph "5.5 Installing the OP-TEE" is enough }} | |||
Latest revision as of 16:23, 16 January 2020
1. Article purpose[edit source]
The pieces of software delivered as source code within the OpenSTLinux Developer Package (for example the Linux kernel) can be modified. External out-of-tree Linux kernel modules, and pieces of applicative software (for example Linux applications) can also be developed thanks to this Developer Package, and loaded onto the board.
The build of all these pieces of software by means of the SDK for OpenSTLinux distribution, and the deployment on-target of the resulting images is explained below. Template:Warning
1.1. Modifying the Linux kernel[edit source]
Prerequisites:
Template:Highlight
☐ configure the Linux kernel
☐ cross-compile the Linux kernel
☐ deploy the Linux kernel (that is, update the software on board)
You can refer to the following simple examples:
- Modification of the kernel configuration
- Modification of the device tree
- Modification of a built-in device driver
- Modification of an external in-tree module
1.2. Adding external out-of-tree Linux kernel modules[edit source]
Prerequisites:
Most device drivers (or modules) in the Linux kernel can be compiled either into the kernel itself (built-in, or internal module) or as Loadable Kernel Modules (LKMs, or external modules) that need to be placed in the root file system under the /lib/modules directory. An external module can be in-tree (in the kernel tree structure), or out-of-tree (outside the kernel tree structure).
External Linux kernel modules are compiled taking reference to a Linux kernel source tree and a Linux kernel configuration file (.config).
Thus, a makefile for an external Linux kernel module points to the Linux kernel directory that contains the source code and the configuration file, with the "-C <Linux kernel path>" option.
This makefile also points to the directory that contains the source file(s) of the Linux kernel module to compile, with the "M=<Linux kernel module path>" option.
A generic makefile for an external out-of-tree Linux kernel module looks like the following:
# Makefile for external out-of-tree Linux kernel module
# Object file(s) to be built
obj-m := <module source file(s)>.o
# Path to the directory that contains the Linux kernel source code
# and the configuration file (.config)
KERNEL_DIR ?= <Linux kernel path>
# Path to the directory that contains the generated objects
DESTDIR ?= <Linux kernel installation directory>
# Path to the directory that contains the source file(s) to compile
PWD := $(shell pwd)
default:
$(MAKE) -C $(KERNEL_DIR) M=$(PWD) modules
install:
$(MAKE) -C $(KERNEL_DIR) M=$(PWD) INSTALL_MOD_PATH=$(DESTDIR) modules_install
clean:
$(MAKE) -C $(KERNEL_DIR) M=$(PWD) clean
Such module is then cross-compiled with the following commands:
$ make clean
$ make
$ make install
You can refer to the following simple example:
1.3. Adding Linux user space applications[edit source]
Prerequisites:
- the SDK is installed
- the SDK is started up
Once a suitable cross-toolchain (OpenSTLinux SDK) is installed, it is easy to develop a project outside of the OpenEmbedded build system.
There are different ways to use the SDK toolchain directly, among which Makefile and Autotools.
Whatever the method, it relies on:
- the sysroot that is associated with the cross-toolchain, and that contains the header files and libraries needed for generating binaries (see target sysroot)
- the environment variables created by the SDK environment setup script (see SDK startup)
You can refer to the following simple example:
1.4. Modifying the U-Boot[edit source]
Prerequisites:
- the SDK is installed
- the SDK is started up
- the U-Boot is installed
Template:Highlight
☐ cross-compile the U-Boot
☐ deploy the U-Boot (that is, update the software on board)
You can refer to the following simple example:
1.5. Modifying the TF-A[edit source]
Prerequisites:
- the SDK is installed
- the SDK is started up
- the TF-A is installed
Template:Highlight
☐ cross-compile the TF-A
☐ deploy the TF-A (that is, update the software on board)
You can refer to the following simple example:
1.6. Modifying the OP-TEE[edit source]
Prerequisites:
- the SDK is installed
- the SDK is started up
- the OP-TEE is installed
Template:Highlight
☐ cross-compile the OP-TEE
☐ deploy the OP-TEE (that is, update the software on board)