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I am learning about Linux boot process on ARM processors and find that U-boot is boot from the flash and then u-boot code intialize the RAM to set up the execution environment like stack set up and all
and relocate itself.
Now my question who initialize the flash so that u-boot code can execute?
Also is it any difference booting it from NOR flash or NAND flash?
Is booting from NOR flash is faster than booting from NAND flash?
naturally someone has to program that flash the first time. And each board design determines how that actually happens, sometimes the part is programmed before being soldered down, sometimes there is a backdoor a connector you can program through, etc. Sometimes not. Sometimes the processor or other hardware on the board has some other kind of bootloader that you can use to program that normal boot flash, etc.
NOR or NAND isnt usually much of a difference, my biggest problem with the newer flashes is worrying about read-disturb. Flash reading is faster than writing and a lot of the effort is or at least needs to be in write speed and density and cost, so I would assume that is where the efforts are and not so much read speed vs write speed. If you have a read speed problem, then just copy the bootloader to ram as soon as you can and run from there, stay off the prom after that.
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I am trying to configure a splashscreen in u-boot on an orange pi zero plus using Armbian.
The screen is connected through spi1 using the ST7789v chip of the LCD.
I already have used systemd to display a splashscreen however I find it slow to display something. It display something only after ~12 sec. I could probably reduce that time a bit by loading the service earlier but it would never start in 5 sec.
It seems that u-boot doesn't take in charge spi as a video output. I can see LCD, HDMI, DVI, VGA,... but no SPI. Is it possible to configure the SPI as LCD? Or to send framebuffer to the SPI to display the splashscreen?
As #KamilCuk mentioned there is no ST7789V driver in U-Boot yet. But you could write your own.
In Linux there is a frame buffer driver drivers/staging/fbtft/fb_st7789v.c which could serve as a template.
On the U-Boot side you can use drivers/video/lg4573.c as a template for a SPI framebuffer driver.
Additionally to the driver you will a device tree overlay describing the SPI device. See Documentation/devicetree/bindings/display/panel/sitronix,st7789v.yaml of the Linux kernel.
Please, send your patches upstream.
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Since I switched to a new AMD Ryzen system my computer lit up.
All new hardware components seem nowadays to have such fancy(?) RGB-LEDs built-in (even in memory modules, even the stock CPU-cooler from AMD).
Is there a way to switch all LEDs in my system off.
The BIOS settings don't offer any control over the LEDs.
Only the mainboard's manufacturers utility software (all for Windows) seems to be capable of controlling that lightning in my computer case.
Is there a way to control such LEDs through Linux Operating System?
A bit late, but just saw this so...for what it is worth...
While most PC mainboard and peripheral manufacturers have created their own proprietary schemes for RGB control via Windows software, some EFI settings allow the mainboard control of them to be turned off. Look into your EFI menus to see if you have that option. I have only Asus mainboards, but they have an option for "stealth" which turns them all off. Otherwise you get that saccharine oscillating rainbow color effect. Good luck.
I run an Asus Tuf B450 with AMD and yes it lights up lie christmas
O.O >blink<
When it starts up press F2 to go into BIOS. There is a top note for Asus Aura. On mine pressing F4 or clicking the slider to off kills all the LED on the board...ALL
Mrs J
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I have run bitbake core-image-minimal-dev properly configured for a genericx86 machine. BitBake generates a bootia32.efi, a bzImage--<stuff>.bin, an .hddimg, an .iso, a .rootfs.ext3, a .rootfs.ext4, a .rootfs.tar.bz2, and a core-image-initramfs-<stuff>.rootfs.cpio.gz. I'm interested in a method of how to dd one or more of these onto the hard disk of my target machine and boot from that hard disk.
dd if=path/to/imagefile/imagename.hddimg of=/dev/usbdevicename
You'll find the correct usb device name e.g. by plugging in the usb disk and looking at dmesg|tail output -- do not guess as mistakes will be fatal to your hard disk. A practical example from my build machine:
sudo dd if=tmp/deploy/images/intel-corei7-64/core-image-sato-intel-corei7-64.hddimg \
of=/dev/sdb \
bs=4096
Note that you probably want to use intel-corei7-64 as the machine unless you know that genericx86 is correct for your hardware: despite the name former is the common Intel BSP for anything that's not ancient (that includes big Cores, Xeons, Atoms ...).
How to boot the image depends on your target device: you may need to go to BIOS settings to select "boot from USB".
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I'm using a small Linux computer in which the software is on an sd card. I needed a program to run at start-up, so I did sudo nano /etc/rc.local and then I added a new line btwn F1 and exit 0 that contains the complete path to my program. This works great, but now I'm locked out. My program runs at start-up like I wanted, but I need to access the program and tweak a few things. I did try putting the sd card in my desktop Windows computer and add init=/bin/sh to the end of the cmdline.txt file. But this had no effect, any suggestions?
Presumably, boot up a desktop Linux machine - mount the sd card, edit the /mnt/etc/rc.local to remove the newline and complete path to your program (from between F1 and exit 0). Then umount the sd card and boot it up. If it won't boot, try and undo that edit to cmdline.txt (which I don't think actually does anything - being a txt file).
This question probably belongs on Super User rather than here.
However, it would probably be easiest for you to get access to a Linux PC and try to edit the file there rather than on the embedded board itself.
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I have googled this question over the internet but couldn't find anything useful related to this question that "why compressed kernel image like bzImage or vmlinuz is used as initial kernel image",
Possible solutions which i could think of are:
Due to memory constraint?
But initially compressed kernel image is located at hard disk or some other storage media and during boot up time after second stage bootloader, kernel is first decompressed in main memory and then it is executed.
So, when at later stage kernel is to be decompressed in main memory then what is the need to compress it first. I mean if main memory could hold decompressed kernel image then what is the need for kernel compression?
Generally the processor can decompress faster than the I/O system can read. By having less for the I/O system to read, you reduce the time needed for boot.
This assumption doesn't hold for all hardware combinations, of course. But it frequently does.
An additional benefit for embedded systems is that the kernel image takes up less space on the non-volatile storage, which may allow using a smaller (and cheaper) flash chip. Many of these systems have ~ 32MB of system RAM and only ~ 4MB of flash.