[U-Boot] how can i change u-boot load address?

[U-Boot] how can i change u-boot load address?

[sahar mustafa]

hi every one..

currently, u-boot load it self in SDRAM address : 0x80100000
i want the u-boot to be loaded to address: 0x80FE0000.
i have try the following:

1#repeating the last steps preform by the build script:
1-./tools/mkimage -A mips -T firmware -C bzip2 -a 0x80100000  -e 0x80100000 
-n 'u-boot image' -d u-boot.bz2 u-boot.zimg
2-./mk_ubootimg.sh head.bin u-boot.zimg 12400 u-boot.img
3-mipsel-linux-objcopy -I binary -O binary --pad-to 0x10000  u-boot.img
u-boot.img
that of course after changing to the new address, but when downloading it to
the board, it hangs

2#in the mkimage.c file, i have change the code a little:

case 'a':
				if (--argc <= 0)
					usage ();
				addr = strtoul ("0x80FE0000", (char **)&ptr, 16);
				*++argv;
				if (*ptr) {
					fprintf (stderr,
						"%s: invalid load address %s\n",
						cmdname, *argv);
					exit (EXIT_FAILURE);

their was no compilation error, but also the board hangs
3# i thought a bout the entry point, and make it to match the load address,
but still the same result.

can you tell me how to change the load address without crippling the u-boot?

with respect
sahar mustafa.

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[U-Boot] how can i change u-boot load address?

[Andrew Dyer]

On Mon, Oct 6, 2008 at 7:13 AM, sahar mustafa <nilesmile@live.com> wrote:
> can you tell me how to change the load address without crippling the u-boot?

It's not 100% clear what you are trying to do, and you didn't mention
your target other than it's MIPS...

If you want to build a version of u-boot that is linked to a start
address that is in RAM for loading via a jtag debugger, then change
the definition of TEXT_BASE in board/<your board name here>/config.mk.
 You have to make sure that u-boot doesn't try to re-initialize the
ram or caches, and doesn't write over parts of itself when it
relocates or allocates memory for the stack and heap.

If you want to make sure u-boot is still linked in ROM, but gets put
at the top of memory during relocation, then you have to make sure the
initdram() function in your code returns the correct ram size.  If you
look in lib_mips/board.c board_init_f(), ram starts being allocated
top down, starting at CFG_SDRAM_BASE + gd->ram_size.  gd->ram_size is
initialized by the return value of a call to initdram() which is
usually somewhere in the board specific code.

-- 
Hardware, n.:
        The parts of a computer system that can be kicked.

[U-Boot] how can i change u-boot load address?

[Roman Mashak]

Hello Andrew,

2008/10/6 Andrew Dyer <amdyer@gmail.com>:
> If you want to build a version of u-boot that is linked to a start
> address that is in RAM for loading via a jtag debugger, then change
> the definition of TEXT_BASE in board/<your board name here>/config.mk.

Can the value of TEXT_BASE be arbitrary chosen for test purposes?

> If you want to make sure u-boot is still linked in ROM, but gets put
> at the top of memory during relocation, then you have to make sure the
> initdram() function in your code returns the correct ram size.

As I understand it's valid for MIPS or PPC based architectures, right?
On many MCUs built on arm7tdmi core (for example, SAM7 family from
Atmel) the process of starting up involves remapping, i.e. 0x0 address
points on ROM at reset and on RAM after remap. U-Boot usually resides
in ROM storage at startup, after reset relocates itself to RAM --
should not it involve remapping as well?

I didn't find how it's done in U-Boot (if it's done at all). Would
appreciate a lot for clarification.

I'm trying to understand how it's done on ARM --

-- 
Roman Mashak

[U-Boot] how can i change u-boot load address?

[Roman Mashak]

Hello

2008/10/6 Roman Mashak <romez777@gmail.com>:

[skip]
> On many MCUs built on arm7tdmi core (for example, SAM7 family from
> Atmel) the process of starting up involves remapping, i.e. 0x0 address
> points on ROM at reset and on RAM after remap. U-Boot usually resides
> in ROM storage at startup, after reset relocates itself to RAM --
> should not it involve remapping as well?
>
> I didn't find how it's done in U-Boot (if it's done at all). Would
> appreciate a lot for clarification.

I seem to understand that remapping, being a CPU specific and
depending on a way U-Boot starts (either from ROM or RAM), is taken
away in 'lowlevel_init' function, defined either in in
$(uboot)/cpu/arm/$(soc)/lowlevel_init.S (for example,
$(uboot)/cpu/arm920t/ks8695/) or in
$(uboot)/board/board_name/lowlevel_init.S, but what confuses me is
that I couldn't find remap functions on every ARM platform, running
from ROM at reset.

-- 
Roman Mashak

[U-Boot] how can i change u-boot load address?

[Wolfgang Denk]

Dear Roman,

In message <40a670230810061636u3c7c3c1dn26f6860a1b463d8b@mail.gmail.com> you wrote:
> 
> Can the value of TEXT_BASE be arbitrary chosen for test purposes?

No, it cannot. You have to define a memory map for your system, which
will result in certain restrictions for the choice of TEXT_BASE.

In general, you have to understand what you are doing, and in detail.

> I'm trying to understand how it's done on ARM --

On ARM it's being done wrong  -  no  real  relocation  is  preformed;
instead,  U-Boot is liked to a fixed address in RAM. The startup code
(mostly assembler) can run from ROM (too).

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
Vulcans believe peace should not depend on force.
	-- Amanda, "Journey to Babel", stardate 3842.3

[U-Boot] how can i change u-boot load address?

[Hebbar]

Hi Wolfgang Denk,


wd wrote:
> 
>> I'm trying to understand how it's done on ARM --
> 
> On ARM it's being done wrong  -  no  real  relocation  is  preformed;
> instead,  U-Boot is liked to a fixed address in RAM. The startup code
> (mostly assembler) can run from ROM (too).
> 
> 

If you can tell me what exactly is wrong with ARM startup, i will try to
find a solution. Can u point the platform and its startup functions where it
is been done correctly. Then i will try to fixup th error in ARM.

Thanks in advance

Regards
Gururaja

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[U-Boot] how can i change u-boot load address?

[Wolfgang Denk]

Dear Hebbar,

In message <19853320.post@talk.nabble.com> you wrote:
> 
> If you can tell me what exactly is wrong with ARM startup, i will try to
> find a solution. Can u point the platform and its startup functions where it
> is been done correctly. Then i will try to fixup th error in ARM.

The fundamental problem with the ARM port is that on ARM, U-Boot gets
linked to a fixed address in RAM.

We inherited this deficiency from the ARMBoot port  -  when  the  old
PPCBoot (PowerPC only) got ported to ARM, the developers thought that
the  whole  relocation  as implemented in PPCBoot was too complicated
and just not worth the effort, so they did what they did. BTW: later,
the MIPS port copied the ARM implementation, unfortunately.

The advantage of the PowerPC implementation with relocation  is  that
we  can  measure  the actual size of memory present on the board, and
then relocate U-Boot to the very end of the RAM,  leaving  nearly  th
whole  RAM  usable as one big contiguous area for "applications" like
loading Linux kernel, ramdisk, etc.

The problem with the ARM implementation is that the link  address  is
fixed,  i. e. it cannot be adjusted to varying RAM sizes. If you have
a board which can be fit with either 32 or with 64  MB  of  RAM,  you
have  to  link  U-Boot  so that it sits at the end of the 32 MB area.
Which means that on a 64 MB system it will sit right in the middle of
the RAM, splitting the RAM in two small chunks. Try to explain  to  a
customer  why  he  has  some  60+ MB of free RAM on the system but he
still cannot load a 33 MB ramdisk image...

There are more consequences from this design  -  on  PowerPC  we  can
implement  "protected  RAM",  framebuffer  memory  we  can share with
Linux, log buffer memory we can share with Linux, etc.  -  all  these
need  to sit at the end of the available physical RAM. On PowerPC, it
goes without saying that all this works perfectly fine with  variable
RAM  sizes  (so we can have one U-Boot image working for example with
different DIMM modules). On ARM, you have to configure U-Boot  for  a
fixed memory size.

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
Respect is a rational process
	-- McCoy, "The Galileo Seven", stardate 2822.3

[U-Boot] how can i change u-boot load address?

[Roman Mashak]

Hello

2008/10/7 Wolfgang Denk <wd@denx.de>:
>> I'm trying to understand how it's done on ARM --
>
> On ARM it's being done wrong  -  no  real  relocation  is  preformed;

What do you mean by "real relocation"? As per start.S bootcode is
copied from ROM to RAM.

> instead,  U-Boot is liked to a fixed address in RAM. The startup code
> (mostly assembler) can run from ROM (too).
However, this is possible if only startup code is in NOR flash.

> The problem with the ARM implementation is that the link  address  is
> fixed,  i. e. it cannot be adjusted to varying RAM sizes.
Usually one ports U-Boot on a board with predefined hardware layout,
i.e. flash, SDRAM and peripherals are fixed. If hardware changes, say
SDRAM size, no big deal to make two/three distinct u-boot images --
after all it ends up by changing TEXT_BASE only, as I understand.

-- 
Roman Mashak

[U-Boot] how can i change u-boot load address?

[Wolfgang Denk]

Dear Roman,

In message <40a670230810070536w5ab3251cm39b1a4ebd199e14a@mail.gmail.com> you wrote:
> 
> > On ARM it's being done wrong  -  no  real  relocation  is  preformed;
> 
> What do you mean by "real relocation"? As per start.S bootcode is
> copied from ROM to RAM.

Copied to a fixed address where it is actiually already  linked  for.
See my previous message with a lenghty explanation why this is a poor
design when dealing with variable sized memory.

> > The problem with the ARM implementation is that the link  address  is
> > fixed,  i. e. it cannot be adjusted to varying RAM sizes.
> Usually one ports U-Boot on a board with predefined hardware layout,
> i.e. flash, SDRAM and peripherals are fixed. If hardware changes, say
> SDRAM size, no big deal to make two/three distinct u-boot images --
> after all it ends up by changing TEXT_BASE only, as I understand.

This may be your opinion, but it is an isolated one and not shared by
*many* board vendors who offer  different  configurations  of  boards
with  smaller and bigger amounts of RAM etc. For these, having only a
single binary image of U-Boot for all board configurations is a MAJOR
win. Also consider systems which use memory modules.

Just try to imagine you have to install a new version of the BIOS  on
your PC just because you add or remove a memory module. Would you buy
such a PC?

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
(null cookie; hope that's ok)

[U-Boot] how can i change u-boot load address?

[Roman Mashak]

Hello

2008/10/7 Wolfgang Denk <wd@denx.de>:
> The advantage of the PowerPC implementation with relocation  is  that
> we  can  measure  the actual size of memory present on the board, and
> then relocate U-Boot to the very end of the RAM,  leaving  nearly  th
When you say "end of the RAM', I think you mean higher addresses, i.e.
0xffff_ffff downwards or lower 0x000_0000 onwards? (this depends on
how to look at memory map, written on a sheet of paper -- straight or
upside down :-) ).

So the bottom line of PPC architecture is that it tries to have
unified booting/relocation process for every platform? For instance,
always copy itself in the upper addresses, occupying, say, 128kB or so
of RAM.

> whole  RAM  usable as one big contiguous area for "applications" like
> loading Linux kernel, ramdisk, etc.

[skip]
> Just try to imagine you have to install a new version of the BIOS  on
> your PC just because you add or remove a memory module. Would you buy
> such a PC?
Well, you convinced me; but despite its flaws and drawbacks the
current ARM port architecture exists and it is here to stay for quite
awhile, unless there will be some hero ready to break it up and build
a new from scratch.

-- 
Roman Mashak

[U-Boot] how can i change u-boot load address?

[Gururaja Hebbar K R]

Hi,

>I seem to understand that remapping, being a CPU specific and
>depending on a way U-Boot starts (either from ROM or RAM), is taken
>away in 'lowlevel_init' function, defined either in in
>$(uboot)/cpu/arm/$(soc)/lowlevel_init.S (for example,
>$(uboot)/cpu/arm920t/ks8695/) or in
>$(uboot)/board/board_name/lowlevel_init.S, but what confuses me is
>that I couldn't find remap functions on every ARM platform, running
>from ROM at reset.

U wouldnt see mapping the vector on (most) ARM Platforms because they
use u-boot as secondary bootloader
Initial Arm Bootmonitor would run & that would re-locate the U-boot to
ram & then give control to u-boot

I said "most" because ARM Integrator Board doesnt use Arm Bootmonitor &
hence its code has remapping functionality.

Kindly look at $(uboot)/board/integratorcp/lowlevel_init.S &
$(uboot)/board/integratorcp/integratorcp.c.
It needs CONFIG_CM_REMAP setting to be defined

For the board that i am using, i had to make use of this.

Hope this helps

Regards
Gururaja

[U-Boot] how can i change u-boot load address?

[Wolfgang Denk]

Dear "Gururaja Hebbar K R",

In message <5BF78BCE8D9BF14A83F836BD9E3916BA23C80C@blrms.slti.sanyo.co.in> you wrote:
> 
> U wouldnt see mapping the vector on (most) ARM Platforms because they
> use u-boot as secondary bootloader

I  don't have reliable statistical data to judge if the "most" is
correct, or if it actually is only a "few" configurations that do
this.

> I said "most" because ARM Integrator Board doesnt use Arm Bootmonitor &
> hence its code has remapping functionality.

[U-Boot] how can i change u-boot load address?

[Gururaja Hebbar K R]

Hi, 

> -----Original Message-----
> From: Wolfgang Denk [mailto:wd at denx.de] 
> Subject: Re: [U-Boot] how can i change u-boot load address?
> 
> > U wouldnt see mapping the vector on (most) ARM Platforms 
> because they 
> > use u-boot as secondary bootloader
> 
> I  don't have reliable statistical data to judge if the 
> "most" is correct, or if it actually is only a "few" 
> configurations that do this.
I meant to say the arm supplied board (integrator[ap/cp], versatile[ap/cp], realview).

> 
> > I said "most" because ARM Integrator Board doesnt use Arm 
> Bootmonitor 
> > & hence its code has remapping functionality.
> 
> From what I'm seeing, "most" systems use U-oot as primary 
> (and  only) boot loader.

S its my mistake. sorry for that.

Regards
Gururaja