{"id":2817,"date":"2023-01-08T20:16:04","date_gmt":"2023-01-09T04:16:04","guid":{"rendered":"https:\/\/doubleecpu.com\/?page_id=2817"},"modified":"2023-02-12T17:44:31","modified_gmt":"2023-02-13T01:44:31","slug":"rustonlyraspberrypi","status":"publish","type":"page","link":"https:\/\/doubleecpu.com\/index.php\/rustonlyraspberrypi\/","title":{"rendered":"Rust Only RaspberryPi Embedded"},"content":{"rendered":"\n

Setup of Rust Development Environment<\/h2>\n\n\n\n

Add Target for Arm architecture<\/h3>\n\n\n\n

Add the compiling for arm architecture if not on an armv7 processor<\/p>\n\n\n\n

rustup target add armv7a-none-eabi<\/code><\/pre>\n\n\n\n
\"\"<\/figure>\n\n\n\n
Create Rust Package<\/h3>\n\n\n\n
Create a Cargo package and include the dependencies 
Use:  cargo new ‘package name’ package
This will create a package name directory with Cargo.toml and src directory with main.rs <\/p>\n\n\n\n
Setup rust to compile for Arm without linux<\/h3>\n\n\n\n
In package name directory create a directory called .cargo 
and add a file called config<\/p>\n\n\n\n
\"\"<\/figure>\n\n\n\n
In the config file add the build configuration for the Processor used in the Raspberry Pi
Pi3 B+ uses ARMv7 <\/p>\n\n\n\n
\"\"<\/figure>\n\n\n\n
Setting up Code File<\/h3>\n\n\n\n
Adjust the main.rs to not include any standard libraries 
adjust the code entry point, to not use main( )  as a start( ) function will be used
make the start function globally accessible for linking so it is ordered the right way
provide external label C and make it manageable by using #![no mangle]<\/p>\n\n\n\n
Create Panic<\/h3>\n\n\n\n
Provide a state panic handler to catch and resolve errors encountered in code
use core::panic::PanicInfo;<\/p>\n\n\n\n
\"\"<\/figure>\n\n\n\n
#![no_std]\n#![no_main]\n\nuse core::panic::PanicInfo;\n\n#[no_mangle]\npub extern \"C\" fn _start() -> ! {\n    loop{}\n}\n\n#[panic_handler]\nfn panic(_info: &PanicInfo) -> ! {\n    loop{}\n}<\/code><\/pre>\n\n\n\n
With this minimum code setup running the command cargo build should complete successfully to indicate Rust is configured.<\/p>\n\n\n\n
\"\"<\/figure>\n\n\n\n
Use ELF Binary File Reader<\/h2>\n\n\n\n
If using Windows download and install XELFviewer from github
https:\/\/github.com\/horsicq\/XELFViewer\/releases <\/p>\n\n\n\n
\"\"<\/figure>\n\n\n\n
Extract contents of zip file and run xelfviewer.exe 
Open the Object Dump File created by Rust (name will match the rust package name)<\/p>\n\n\n\n
\"\"
Make note of the Entry point address: 000200e4
This needs to be changed to 0008000e4 in linker<\/figcaption><\/figure>\n\n\n\n
To install in debian based distro Install the following<\/p>\n\n\n\n
sudo apt-get install file\nsudo apt-get elfrc elfutils libasm1\nsudo apt-get install gcc-arm-none-eabi<\/code><\/pre>\n\n\n\n
Create Linker Script<\/h2>\n\n\n\n
Next the Hex Code for the start address needs to be set by the Linker Script when building the solution.
In the package folder create text file called linker.ld and set the following script<\/p>\n\n\n\n
ENTRY(_start)\n \nSECTIONS\n{\n    . = 0x8000;\n    __start = .;\n    .text :\n    {\n        KEEP(*(.text.boot))\n        *(.text)\n    }\n    . = ALIGN(4096);\n    .rodata :\n    {\n        *(.rodata)\n    }\n    . = ALIGN(4096);\n    .data :\n    {\n        *(.data)\n    }\n    . = ALIGN(4096);\n    __bss_start = .;\n    .bss :\n    {\n        bss = .;\n        *(.bss)\n    }\n    . = ALIGN(4096); \n    __bss_end = .;\n    __bss_size = __bss_end - __bss_start;\n    __end = .;\n}<\/code><\/pre>\n\n\n\n
Add to main.rs<\/p>\n\n\n\n
#![no_std]\n#![no_main]\n\nuse core::panic::PanicInfo;\nmod boot {\n    use core::arch::global_asm;\n\n    global_asm!(\n        \".section .text._start\"\n    );\n}\n#[no_mangle]\npub extern \"C\" fn _start() -> ! {\n    loop{}\n}\n\n#[panic_handler]\nfn panic(_info: &PanicInfo) -> ! {\n    loop{}\n}<\/code><\/pre>\n\n\n\n
Run the rust compiler this time with the linker script. *Delete Target Folder whenever you modify the linker.ld file.<\/p>\n\n\n\n
cargo rustc -- -C link-arg=--script=.\\linker.ld<\/code><\/pre>\n\n\n\n
\"\"<\/figure>\n\n\n\n
\"\"
_start is now 0008000<\/figcaption><\/figure>\n\n\n\n
Next the unusable code generated for Linux must be removed to run on bare metal RaspberryPi 
The code to run on the RaspberryPi must be extracted from the ELF file. <\/p>\n\n\n\n
 arm-none-eabi-objcopy -O binary rust_pi_embedded .\/rust_pi.img<\/code><\/pre>\n\n\n\n
This will create the executable code that will run on the raspberry pi as “baremetal” without Linux OS<\/p>\n\n\n\n
Reference Documentation for GPIO<\/h2>\n\n\n\n
When designing software for the hardware of RaspberryPi without Linux the Broadcom BCM3837 ARM Peripherals manual should be used. Official RasberryPi Links<\/a> <\/p>\n\n\n\n
\"\"<\/figure>\n\n\n\n
\"\"<\/figure>\n\n\n\n
\"\"<\/figure>\n\n\n\n
\"\"<\/figure>\n\n\n\n
Set Pin to GPIO  <\/p>\n\n\n\n
Setting up GPIO pins<\/h3>\n\n\n\n
Setting Pin 21 to on and off. <\/p>\n\n\n\n
Select Pin From the datasheet and copy the register address <\/p>\n\n\n\n
<\/p>\n\n\n\n
Add a do nothing loop<\/p>\n\n\n\n
Setting Up i2c<\/p>\n\n\n\n
<\/p>\n\n\n\n
Firmware Files<\/h2>\n\n\n\n
Download Github Firmware files<\/h3>\n\n\n\n
From the github repository<\/a> download and install files required to run the image on the RaspberryPi
https:\/\/github.com\/raspberrypi\/firmware\/blob\/master\/boot\/bootcode.bin
https:\/\/github.com\/raspberrypi\/firmware\/blob\/master\/boot\/fixup.dat
https:\/\/github.com\/raspberrypi\/firmware\/blob\/master\/boot\/start.elf
<\/p>\n\n\n\n
Create Config<\/h3>\n\n\n\n
Create a file config.txt include the following configuration settings<\/p>\n\n\n\n
arm_64bit=0<\/code><\/pre>\n\n\n\n
Combine the Files into a directory <\/h3>\n\n\n\n
copy the files into a directory: bootcode.bin  fixup.dat start.elf config.txt kernel7.img<\/p>\n\n\n\n
to boot partition<\/p>\n","protected":false},"excerpt":{"rendered":"
Setup of Rust Development Environment Add Target for Arm architecture Add the compiling for arm architecture if not on an armv7 processor Create Rust Package Create a Cargo package and include the dependencies Use: cargo new ‘package name’ packageThis will create a package name directory with Cargo.toml and src directory with main.rs Setup rust to … <\/p>\n
Read more “Rust Only RaspberryPi Embedded”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-2817","page","type-page","status-publish","hentry"],"featured_media_urls":[],"_links":{"self":[{"href":"https:\/\/doubleecpu.com\/index.php\/wp-json\/wp\/v2\/pages\/2817","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/doubleecpu.com\/index.php\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/doubleecpu.com\/index.php\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/doubleecpu.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/doubleecpu.com\/index.php\/wp-json\/wp\/v2\/comments?post=2817"}],"version-history":[{"count":9,"href":"https:\/\/doubleecpu.com\/index.php\/wp-json\/wp\/v2\/pages\/2817\/revisions"}],"predecessor-version":[{"id":2872,"href":"https:\/\/doubleecpu.com\/index.php\/wp-json\/wp\/v2\/pages\/2817\/revisions\/2872"}],"wp:attachment":[{"href":"https:\/\/doubleecpu.com\/index.php\/wp-json\/wp\/v2\/media?parent=2817"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}