[U-Boot] start address loading initrd in ram on arm

[Joren Bultheel]

Thank you!

So in my situation; after loading the kernel in ram, I know where to load
my initrd image:

U-Boot > printenv boot_dev

boot_dev=mmc dev 2; ext2load mmc 2:1 0x10800000 /boot/uImage


U-Boot > run boot_dev

mmc2(part 0) is current device

Loading file "/boot/uImage" from mmc device 2:1 (xxc1)

4284096 bytes read


U-Boot > bdi

arch_number = 0x00001194

env_t       = 0x00000000

boot_params = 0x10000100

DRAM bank   = 0x00000000

-> start    = 0x10000000

-> size     = 0x80000000


This means that I can only use the address range between 0x10000000 and
0x80000000
Since the kernel is loaded at address 0x10800000 with size 4284096 bytes
(415ec0 in hex), I can start loading my initrd at address (0x10800000 +
415ec0 = ) 0x10c15ec0

The initrd size = 27237386 bytes but this does not matter here, I give this
size as a kernel argument.

I tested this and it works fine on my ARM machine.


On Thu, Feb 27, 2014 at 3:30 PM, Tom Rini <trini at ti.com> wrote:

> On Thu, Feb 27, 2014 at 11:50:33AM +0100, Joren Bultheel wrote:
>
> > Which address should I give when loading an initrd into ram using U-boot
> on
> > an arm-based architecture?
> > How can I find out?
> >
> > I have found many google hits where people are loading initrd files in
> ram
> > but they use always another target ram address.
> > It is never explained why they use 0x70000000 or 0x01200000 or ...
> >
> > In my case 0x70000000 does work finally, but I can not figure out why
> > 0x40000000 did not.
>
> Well, it depends on your platform as system ram starts in different
> locations on different platforms.  For example:
> U-Boot# bdi
> arch_number = 0x00000E05
> boot_params = 0x80000100
> DRAM bank   = 0x00000000
> -> start    = 0x80000000
> -> size     = 0x40000000
> ...
>
> And you also need to keep in mind where you load your kernel into memory
> and how big it is.
>
> --
> Tom
>



-- 
Joren Bultheel
Software Engineer

eSATURNUS
T. +32 16 40 12 82
www.esaturnus.com