How to run core-image-tiny-initramfs.cpio.gz (or ramfs / ramdisk.gz) from an SD card

[ScottSJ]

Hello,

Using an 8Mplus eval board, we need to run core-image-tiny-initramfs or a ramfs from SD card. I can build the image but can't find the correct uboot commands to use it. I see references in other posts to core-image-tiny-initramfs.cpio.gz but those posts don't list the uboot commands.

I've tried these commands:
setenv loadramdisk "load mmc 2:2 0x80000000 /boot/ramdisk.gz"
setenv ramargs "setenv bootargs ${mmcargs} root=/dev/ram0 rw rootfstype=ext4 ramdisk_size=0x20000000"
setenv ramboot "echo Booting from ramdisk ...; run ramargs; bootz ${loadaddr} 0x80000000 ${fdt_addr_r}"
setenv bootcmd "run loadimage loadfdt loadramdisk ramboot"

I always get the error message "zimage: Bad magic!"

I suspect the problem is the address. According to the sources for imx8mp-evk.dtb the ram address should be valid but there are no messages from uboot.

Thanks,
Scott

[goodspeed]

If you check the u-boot help, you can easily find how to use ramdisk.

u-boot=> help booti
booti - boot Linux kernel 'Image' format from memory

Usage:
booti [addr [initrd[:size]] [fdt]]
- boot Linux 'Image' stored at 'addr'
The argument 'initrd' is optional and specifies the address
of an initrd in memory. The optional parameter ':size' allows
specifying the size of a RAW initrd.
Since booting a Linux kernel requires a flat device-tree, a
third argument providing the address of the device-tree blob
is required. To boot a kernel with a device-tree blob but
without an initrd image, use a '-' for the initrd argument.

[ScottSJ]

Hello,

Does anyone have an answer? Is there documentation for using the supplied core-image-tiny-initramfs?

Thanks,
Scott

[Bio_TICFSL]

Hello,

If you just want to build uboot, why don't use stand alone uboot ? for more detailed information, pls refer to the chapter Chapter 3 Porting U-Boot.

https://www.nxp.com/docs/en/user-guide/IMX_PORTING_GUIDE.pdf

Regards

[ScottSJ]

Hello,

Is there any documentation or information how to use the supplied ramfs recipes?

Thanks,
Scott

[goodspeed]

I had already told you!!!
And It is from u-boot document. It is a document!!!

If you check the u-boot help, you can easily find how to use ramdisk.

u-boot=> help booti
booti - boot Linux kernel 'Image' format from memory

Usage:
booti [addr [initrd[:size]] [fdt]]
- boot Linux 'Image' stored at 'addr'
The argument 'initrd' is optional and specifies the address
of an initrd in memory. The optional parameter ':size' allows
specifying the size of a RAW initrd.
Since booting a Linux kernel requires a flat device-tree, a
third argument providing the address of the device-tree blob
is required. To boot a kernel with a device-tree blob but
without an initrd image, use a '-' for the initrd argument.

If you check the uuu script 'example_kernel_emmc.uuu' in the binary release tar ball, you will find how to use the ramdisk.

FB: ucmd setenv fastboot_buffer ${loadaddr}
FB: download -f _Image
FB: ucmd setenv fastboot_buffer ${fdt_addr}
FB: download -f _board.dtb
FB: ucmd setenv fastboot_buffer ${initrd_addr}
FB: download -f _initramfs.cpio.gz.uboot
#FB: ucmd setenv bootargs console=${console},${baudrate} earlycon=${earlycon},${baudrate}
FB: acmd ${kboot} ${loadaddr} ${initrd_addr} ${fdt_addr}

FB: acmd ${kboot} ${loadaddr} ${initrd_addr} ${fdt_addr}
u-boot=> help booti
booti - boot Linux kernel 'Image' format from memory

Usage:
booti [addr [initrd[:size]] [fdt]]

kboot here is booti
loadaddr here is addr
initrd_addr here is initrd and it is ramdisk and it could be core-image-tiny-initramfs.cpio.gz
fdt here is fdt_addr

Again, I had already told you everything!!!

"without an initrd image, use a '-' for the initrd argument."
That is why you often see the '-' in boot command line with linux kernel and device tree dts. 

Because the most of time, no need ramdisk.

It is just a u-boot basic knowledge. Very basic. 

[ScottSJ]

It's ok if you don't know where to find documentation. If this is "basic knowledge", there should be documentation available somewhere but I haven't found anything after many web searches.

I'm well aware of the various "boot" commands and have used them on other platforms. I've reviewed the source code and other boot configurations. I'm looking for the specific values and parameters needed for the nxp platform. This should be available with the "core-image-tiny-initramfs" build, but I can't find the steps to use that image. (I do have the steps to use a regular rootfs booting on an SD card, but we need both environments.)

[kimease]

maybe this demo can help you. 

It is just a u-boot booti command. You can change the booti to bootz according to your kernel image format(Image, zImage, etc)

booti ${loadaddr} ${initrd_addr} ${fdt_addr}

The initrd_addr  is location/address of uramdisk_boot.rootfs.aarch64.img ramdisk. 

should be core-image-tiny-initramfs.cpio.gz in your case.

|-- 0001-all-in-spi-demo-lf-5.10.72-2.2.0.patch --- patch for this demo
|-- demo_binary
| |-- flash.b0.bin --- b0 bootloader
| |-- flash.bin --- c0 bootloader
| |-- Image-imx8qxpc0mek.bin --- Linux kernel
| |-- imx8qxp-mek.dtb --- device tree
| |-- uramdisk_boot.rootfs.aarch64.img --- ram disk
| |-- uuu.qspi.all.b0.uuu --- uuu script for b0
| `-- uuu.qspi.all.uuu --- uuu script for c0
`-- readme.txt --- this file

https://community.nxp.com/t5/i-MX-Processors-Knowledge-Base/all-bootloader-device-tree-Linux-kernel-...

[kimease]

I notice you said "I do have the steps to use a regular rootfs booting on an SD card, but we need both environments". 

Suggest you can read the page 35 of  SWUpdate OTA i.MX8MM EVK_rev3.pdf

SWUpdate OTA i.MX8MM EVK / i.MX8QXP MEK - NXP Community

Maybe that is what you want.

[ScottSJ]

Hello,

We need to boot multiple kernels and/or ramfs from a single uboot. The target can be determined in uboot code, which can set the appropriate environment variables. We've done this on other systems so it should be able to be done here.

We already have the code to detect and use different kernels. We need to steps to boot a ramfs.

Thanks,
Scott