I have a some problem with device reconizing at te system boot time. I have tried to get some information with udev_log="debug" - no success. It's looks like that udev works on data has been built by some other process.
So, is there a way to debug a process of scanning MBR and GPT during system startup ?
This is under Ubuntu 16.x-18.x, kernel 4.4-4.15.
Related
I built a certain driver as module (m) for Linux, the spi-imx by NXP. Nontheless, Linux probes this driver when booting. I'm struggling to find out what process/other module/driver requests this spi-imx driver. A depmod does not show any dependencies between the spi-imx an other modules (except for the spidev as submodule).
After some research, I found out that Linux automatically (?) calls modprobe when it detects a new device. So does Linux actually call modprobe because the ecSPI'S status in the device tree as "okay"? If so, how can I prevent this? I would like to dynamically load the spi-imx from a user space application via modprobe. The story behind it: a coprocessor uses this SPI line in parallel to the Linux boot process. This interferes of course and interrupts the coprocessor's use of the SPI line. When the coprocessor has finished its transfer via SPI (a boot mechanism as well), it should hand over the SPI line to Linux.
I'm very thankful for any kind of tips, links, hints and comments on this.
Thanks a lot for the answers. As you guys mentioned, I also found out that Linux itself probes the device if present ("okay").
One possible solution is to complete cut off the modprobe call via an entry like "install spi-imx /bin/false" in the *.conf file. But that makes it impossible to load the driver via modprobe, for Linux and for user space.
"blacklist spi-imx" inside a *.conf located at /etc/modprobe.d/ is the way to prevent Linux from probing the driver when booting. After that, a modprobe from user space can successfully load the driver afterwards.
Thanks again & best regards
I've recently been getting into bare metal development for the Raspberry Pi 2, and having some success. Admittedly I've hesitated to buy an actual physical device until I feel I can do something useful with it, for the time being I've been emulating the device using qemu 2.11.0.
So far I've developed multicore capabilities for my kernel, as well as simple Serial I/O, but I feel I'd like to get much further before working with a physical device.
My issue right now is that I'm trying to learn how to place my kernel onto an SD card image and boot qemu-system-arm from that SD card image, so I can properly emulate a kernel loaded from the raspberry pi 2 bootloader.
I've gotten as far as grabbing the SD card contents from https://github.com/raspberrypi/firmware ... aster/boot, and using the following script to create the image and load my kernel into it. I've seen that people have figured out how to load Raspbian from an emulated SD card, so I figure I can do the same.
#!/bin/bash
OUTPUT_IMG=os.img
OUTPUT_IMG_SIZE=40
TEMP_MOUNT_DIR="$(mktemp -d)"
# the SD card boot partition contents are in this folder...
OUTPUT_IMG_CONTENTS_DIR="./sd"
OS_DIR="${HOME}/os"
OS_BINARY="${OS_DIR}/kernel.bin"
dd if=/dev/null of=${OUTPUT_IMG} bs=1M seek=${OUTPUT_IMG_SIZE}
mkfs.fat -F 32 ${OUTPUT_IMG}
sudo mount -t vfat -o loop ${OUTPUT_IMG} ${TEMP_MOUNT_DIR}
make -C ${OS_DIR} clean
make -C ${OS_DIR}
sudo cp -r ${OUTPUT_IMG_CONTENTS_DIR} ${TEMP_MOUNT_DIR}
sudo cp ${OS_BINARY} "${TEMP_MOUNT_DIR}/kernel.img"
The only issue is that qemu doesn't seem to boot from this image using the following command:
qemu-system-arm -machine raspi2 -serial file:serial.log -sd ./dev/os.img
I've tried a few different combinations, but to no avail.
I can see from hooking GDB that the kernel is simply not booting from this card image. Loading the kernel directly into qemu with the -kernel argument works otherwise perfectly.
I was wondering if anyone here had any insight on how to accomplish this!
Any help here would be greatly appreciated!
Your command won't work because you haven't passed QEMU either a guest BIOS or a guest kernel to run. The QEMU arm boards aren't like the x86 PC machine, which always automatically runs a guest BIOS image. If you want to run a BIOS (probably UEFI?) you need to find a suitable BIOS blob and pass it to QEMU with the -bios argument. Then QEMU will run the BIOS code, which will hopefully include SD card drivers to load the kernel and so on off the SD card.
Just using -kernel is much simpler...
After doing a bit of reading and searching online, as well as a bit of help from other contributors such as Peter Maydell with his answer above, I think I've answered my own question. Unless I'm mistaken qemu-system-arm does not fully emulate the Raspberry Pi boot process, and instead just loads the kernel specified with the -kernel argument by loading the binary into the guest system's memory and jumping to the entry point. It doesn't look like any additional hardware bootloading is emualted for -M raspi2 unfortunately.
Can ARM qemu system emulator boot from card image without kernel param?
This question is similar and contains some more useful details on this issue, relating to qemu-system-arm as a whole..
I'm trying to get MSI-X working on an iMX6 (Freescale/NXP/Qualcomm) CPU in Linux v4.1 for a PCIe character device driver. Whenever I call either pci_enable_msix() or pci_enable_msix_range() or pci_enable_msix_exact() I get an EINVAL value returned. I do have the CONFIG_PCI_MSI option selected in the kernel configuration and I am also able to get single MSI working with pci_enable_msi(), but I cannot get multiple MSI working either.
I have tested my driver code on an Intel i7 running kernel v3 with the same PCIe hardware attached and I was able to get MSI-X working without any problems so I know my code is correctly written and the hardware is correctly functioning.
When running on the iMX6 I can use lspci -v to view that the hardware has MSI-X capabilities and see the number of IRQs it allows. I can even get the same correct number in my driver when calling pci_msix_vec_count().Questions
Are there any other kernel configuration flags I need to set?
Is there anything specific to the iMX6 CPU I need to consider?
Does anyone have any experience with the iMX6 and either MSI-X or
multiple MSI?
I have Hackintosh build by a friend back in 2012. I need some files from it now but I can not access it. I see white screen after I login with my infos. Mouse and keyboard works but I only see white screen. I get to see wallpaper background with login when I press Power button. But when I login only whites screen. Im using HDMI on dedicated GTX 670. I also tried DVI without luck - same white screen after login. I pull out GTX out and RAM memory. No any differences. I tried different options on boot. -v -s (-f i can not log with). Also tried GraphicsEnabler=On/Off. I just need some files from Drives and then I can wipe out the system. Can you help me and tell if you have experience to solve this problem?
Specs:
Darwin/x86 boot v5.0.132 - Chimera v1.8.0
16 GB RAM
Intel i7-2600 #3.40Ghz
NVIDIA GeForce GTX 560
Lion OSX
Take out your HDD/SSD drive from the hackintosh and connect it to any Mac with a USB to SATA adapter. (If you have another hackintosh, just plug the drive to the other PC).
Note that regular 3.5" hard disks require a powered USB to SATA adapter, because these drives are unable to power with a single USB port.
I am currently developing a small OS on my Raspberry Pi, that I install by replacing the kernel.img file on the /boot partition of my SD card. By the time my code is run, the CPU is already in Normal Mode, so I can't have access to the Secure world / Trustzone area.
Is it possible to modify the boot process of the Raspberry to be able to start executing my code in Secure mode ?
Best,
V.
In fact you don't have to do anything but stop being stupid like me.
As explained here:
https://raspberrypi.stackexchange.com/questions/14953/is-it-possible-to-boot-the-raspberry-pi-in-secure-mode
When the NS bit of the SCR register is 0, it means that you are in Secure Mode, which is the case at boot on my Raspberry. I had the meaning of this bit backwards, sorry !