[U-Boot] Passing bootargs to arm64 kernel
Hello. I'm trying to find a way how to pass bootargs to arm64 kernel.
In arm32 kernel, we can pass bootargs with atag from u-boot to kernel. So, we can overwrite kernel's bootargs with u-boot's bootargs.
But from arm64 kernel, the dtb is the only argument that should be passed from bootloader which is mandatory. you can find this contents in kernel documentation.(Documentation/arm64/Booting.txt)
So, is there any way how to set bootargs by u-boot?
Thanks.
On Wed, Aug 13, 2014 at 11:21:32AM +0900, Youngmin Nam wrote:
Hello. I'm trying to find a way how to pass bootargs to arm64 kernel.
In arm32 kernel, we can pass bootargs with atag from u-boot to kernel. So, we can overwrite kernel's bootargs with u-boot's bootargs.
But from arm64 kernel, the dtb is the only argument that should be passed from bootloader which is mandatory. you can find this contents in kernel documentation.(Documentation/arm64/Booting.txt)
So, is there any way how to set bootargs by u-boot?
Yes, within the device tree, like we do today. There's a few issues we have today, but I need to re-post the booti command support patches, given what's coming in 3.17 in the kernel.
Thank you for reply Tom, Let me ask you some questions.
Can we set kernel's bootargs without re-compiling device tree on arm64 kernel by u-boot?
I mean, I want to set kernel's bootargs by u-boot without re-compiling device tree.
Is it possible? 2014. 8. 13. 오후 7:39에 "Tom Rini" trini@ti.com님이 작성:
On Wed, Aug 13, 2014 at 11:21:32AM +0900, Youngmin Nam wrote:
Hello. I'm trying to find a way how to pass bootargs to arm64 kernel.
In arm32 kernel, we can pass bootargs with atag from u-boot to kernel.
So,
we can overwrite kernel's bootargs with u-boot's bootargs.
But from arm64 kernel, the dtb is the only argument that should be passed from bootloader which is mandatory. you can find this contents in kernel documentation.(Documentation/arm64/Booting.txt)
So, is there any way how to set bootargs by u-boot?
Yes, within the device tree, like we do today. There's a few issues we have today, but I need to re-post the booti command support patches, given what's coming in 3.17 in the kernel.
-- Tom
On 08/14/2014 08:04 AM, Youngmin Nam wrote:
Thank you for reply Tom, Let me ask you some questions.
Can we set kernel's bootargs without re-compiling device tree on arm64 kernel by u-boot?
I mean, I want to set kernel's bootargs by u-boot without re-compiling device tree.
Is it possible?
This is done anyway, whatever is defined in CONFIG_BOOTARGS will be stored in the U-Boot environment variable bootargs and passed as bootargs to the kernel via the "chosen" node.
See fdt_chosen in common/fdt-support.c.
So if you want the change the bootargs passed to the kernel, just do
set bootargs '<whatever you want in bootargs>'
at the u-boot prompt and the boot the kernel.
Thanks Arnab
- 오후 7:39에 "Tom Rini" trini@ti.com님이 작성:
On Wed, Aug 13, 2014 at 11:21:32AM +0900, Youngmin Nam wrote:
Hello. I'm trying to find a way how to pass bootargs to arm64 kernel.
In arm32 kernel, we can pass bootargs with atag from u-boot to kernel.
So,
we can overwrite kernel's bootargs with u-boot's bootargs.
But from arm64 kernel, the dtb is the only argument that should be passed from bootloader which is mandatory. you can find this contents in kernel documentation.(Documentation/arm64/Booting.txt)
So, is there any way how to set bootargs by u-boot?
Yes, within the device tree, like we do today. There's a few issues we have today, but I need to re-post the booti command support patches, given what's coming in 3.17 in the kernel.
-- Tom
participants (3)
-
Arnab Basu -
Tom Rini -
Youngmin Nam