boot command line

[[email protected]]

Using Robert Nelsons how to: Latest 3.17 kernel and trying to use the boot command line.
The uboot command line is as follows:
"console=ttymxc0,115200 ip=dhcp root=/dev/mmcblk0p1 rootwait rw mmcinfo ext2load mmc 0:1 0x10800000 uImage ext2load mmc 0:1 0x12000000 imx6q-darde.dtb bootm 0x10800000 - 0x12000000"

The question is how do I translate that into a working boot command line so that I can get to a login in on runlevel 2?

I added it to CONFIG_CMDLINE with multiple renditions to no avail.
I also disabled CONFIG_CMDLINE_FROM_BOOTLOADER

Thanks

[robertferanec]

I do not remember exactly, but 3.17 may not be taking the command line from uBoot. When you run Kernel, have a look if the command line you are putting into the uBoot is the same as the command line reported by Kernel during booting.

[[email protected]]

Yes I knew it is not booting from uBoot. Here is a clue to the issue:

The 3.10.17 kernel that boots from uBoot shows this at bootup

"console=ttymxc0,115200 ip=dhcp root=/dev/mmcblk0p1 rootwait rw root=/dev/mmcblk0p1 rootwait rw"

Looking at be printenv it shows
bootargs "console=ttymxc0,115200 ip=dhcp root=/dev/mmcblk0p1 rootwait rw mmcinfo ext2load mmc 0:1 0x10800000: uImage"
bootargs_fdt "ext2load mmc 0:1 0x12000000 imx6q-darde.dtb bootm 0x10800000 - 0x12000000"
boot_cmd "bootargs bootargs_fdt"

So I make the 3.17 kernel CONFIG_CMDLINE look like the following:

"console=ttymxc0,115200 ip=dhcp root=/dev/mmcblk0p1 rootwait rw root=/dev/mmcblk0p1 rootwait rw"

But when the kernel boots it only shows one root=xxx as in

"console=ttymxc0,115200 ip=dhcp root=/dev/mmcblk0p1 rootwait rw"

The second root= is missing.
That I am assuming is my dtb load??

So I can not seem to create the exact build line from uBoot.

[robertferanec]

I would try to change the CONFIG_CMDLINE "mmcblk0p1" to "mmcblk1p1" and see if the kernel boots changes too. I would also try to search for "console=ttymxc0,115200 ip=dhcp root=/dev/mmcblk0p1 rootwait rw" in the source code, maybe it is defined somewhere else.

[[email protected]]

I did and no that did not help. The 2 cmd lines that are brought over from uboot: One is for the kernel and the other for the device tree. So it seems that it is dying in the dtb somehow.
That I do not understand as it is the same device tree (recompiled with the new kernel) as what I am using in the 3.10.17 kernel and it is booting to level 2 properly.

[robertferanec]

I am not a software guy, so I do not really know. Please, when you find out what is problem, let us know - also how you fixed that. I am interested to know as I needed this for couple of times and I didn't know how to change it.

[[email protected]]

Answer: uboot env var

setenv kernel_address 0x10008000
setenv dtb_address 0x12000000


setenv bootm "$kernel_address $initrd_address $dtb_address"

or w/o initrd

setenv bootm "$kernel_address - $dtb_address"
saveenv

[robertferanec]

Thank you!
So, you need to boot it through bootm and specify the device tree as second parameter. That is actually the way to start the kernels with device tree.

[[email protected]]

Actually, there are 3 parameters: $kernel_addr $initrd_addr $dtb_addr. They need to be in that order.
Make sure you put a "-" (dash) for each one not present on the boot command line

[robertferanec]

Thank you!