in mips how to change the start address to the new second boot loader ?

in mips how to change the start address to the new second boot loader ?

[nagalakshmi veeramallu]

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Hi ,
 I have a KMC board with mips VR4131 processor. The target board already
 having cmon boot loader on flash. Now I need to put my yamon boot loader
 which I modified according to the requirement on the flash. As we know MIPS
 have fixed starting address 0xbfc00000, how to change this address to other
 address so that after power on it can enter to the new address (boot
 loader).
If any one have some idea, please help me
Thanks in advance.



Regards,

Lucky

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in mips how to change the start address to the new second boot loader ?

[nagalakshmi veeramallu]

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Hi ,
 I have a KMC board with mips VR4131 processor. The target board already
 having cmon boot loader on flash. Now I need to put my yamon boot loader
 which I modified according to the requirement on the flash. As we know MIPS
 have fixed starting address 0xbfc00000, how to change this address to other
 address so that after power on it can enter to the new address (boot
 loader).
If any one have some idea, please help me
Thanks in advance.



Regards,

Lucky

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Re: in mips how to change the start address to the new second boot loader ?

[Florian Fainelli]

Hi,

Le Wednesday 15 April 2009 08:09:01 nagalakshmi veeramallu, vous avez écrit :
> Hi ,
>  I have a KMC board with mips VR4131 processor. The target board already
>  having cmon boot loader on flash. Now I need to put my yamon boot loader
>  which I modified according to the requirement on the flash. As we know
> MIPS have fixed starting address 0xbfc00000, how to change this address to
> other address so that after power on it can enter to the new address (boot
> loader).

You cannot indeed change the boot address, but you can place a routine, or 
even a bootloader at 0x1fc00000 which jumps to an arbitrary address.
-- 
Best regards, Florian Fainelli
Email : florian@openwrt.org
http://openwrt.org
-------------------------------

Re: in mips how to change the start address to the new second boot loader ?

[M. Warner Losh]

In message: <200904201100.39164.florian@openwrt.org>
            Florian Fainelli <florian@openwrt.org> writes:
: Hi,
: 
: Le Wednesday 15 April 2009 08:09:01 nagalakshmi veeramallu, vous avez écrit :
: > Hi ,
: >  I have a KMC board with mips VR4131 processor. The target board already
: >  having cmon boot loader on flash. Now I need to put my yamon boot loader
: >  which I modified according to the requirement on the flash. As we know
: > MIPS have fixed starting address 0xbfc00000, how to change this address to
: > other address so that after power on it can enter to the new address (boot
: > loader).
: 
: You cannot indeed change the boot address, but you can place a routine, or 
: even a bootloader at 0x1fc00000 which jumps to an arbitrary address.

I tried to tell him that in the FreeBSD/mips list, but he wouldn't
listen to me there either...  The simple fact is that the Vr41xx
processors cannot move their boot address at all....

Warner

Re: in mips how to change the start address to the new second boot loader ?

[nagalakshmi veeramallu]

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Hi,

Thanks for your reply.

            Actual YAMON doesn’t have support for KMC board, hence we
modified yamon source code according to the KMC board. Now we want to put
our code into FUJITSU flash memory for testing purpose and  previous boot
loader cmon has to be protected. After power on the board, instead of cmon
we have to run our modified Yamon.

            CMON is executing perfectly, is there any possible way to go
directly to the new boot loader code directly. i have some idea, is this
approach will work

-          if we set environmental variable “start” as “go new_address”,
will it go directly to the new bootloader in the next power-on.

-           Mips atlas board has jumper  which will redirect accesses from
“Bootcode” range to either “Monitor flash” (0x1e000000) or the upper 4MB of
“System flash” (0x1dc00000) based on jumper settings. if my kmc board have
some jumper like this, can I redirect the start address.

Thanks in advance

 Regards,

Lucky

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Re: in mips how to change the start address to the new second boot loader ?

[nagalakshmi veeramallu]

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Hi,

Thanks for your reply.

            Actual YAMON doesn’t have support for KMC board, hence we
modified yamon source code according to the KMC board. Now we want to put
our code into FUJITSU flash memory for testing purpose and  previous boot
loader cmon has to be protected. After power on the board, instead of cmon
we have to run our modified Yamon.

            CMON is executing perfectly, is there any possible way to go
directly to the new boot loader code directly. i have some idea, is this
approach will work

-          if we set environmental variable “start” as “go new_address”,
will it go directly to the new bootloader in the next power-on.

-           Mips atlas board has jumper  which will redirect accesses from
“Bootcode” range to either “Monitor flash” (0x1e000000) or the upper 4MB of
“System flash” (0x1dc00000) based on jumper settings. if my kmc board have
some jumper like this, can I redirect the start address.

Thanks in advance

 Regards,

Lucky

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Re: in mips how to change the start address to the new second boot loader ?

[Kevin D. Kissell]

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Re: in mips how to change the start address to the new second boot loader ?

[nagalakshmi veeramallu]

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hi,
         --          if we set environmental variable “start” as “go
new_address”, will it go directly to the new bootloader in the next
power-on.

what about using system environmental "start" ,can you tell me at which
context after power on environmental variables come onto picture.

Regards,
Lucky

On Tue, Apr 21, 2009 at 6:55 PM, Kevin D. Kissell <kevink@paralogos.com>wrote:

>  nagalakshmi veeramallu wrote:
>
>  -           Mips atlas board has jumper  which will redirect accesses
> from “Bootcode” range to either “Monitor flash” (0x1e000000) or the upper
> 4MB of “System flash” (0x1dc00000) based on jumper settings. if my kmc
> board have some jumper like this, can I redirect the start address.
>
> Of course, what is really happening there is that the Atlas boot ROM has a
> vector at 0x1fc00000 which reads the jumper and jumps to one address or the
> other depending on the jumper setting. If you control what is in ROM at
> 0x1fc00000 and you have a software-readable jumper on your KMC board, you
> can do the same thing.
>
>           Regards,
>
>           Kevin K.
>
>

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Re: in mips how to change the start address to the new second boot loader ?

[nagalakshmi veeramallu]

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hi,
         --          if we set environmental variable “start” as “go
new_address”, will it go directly to the new bootloader in the next
power-on.

what about using system environmental "start" ,can you tell me at which
context after power on environmental variables come onto picture.

Regards,
Lucky

On Tue, Apr 21, 2009 at 6:55 PM, Kevin D. Kissell <kevink@paralogos.com>wrote:

>  nagalakshmi veeramallu wrote:
>
>  -           Mips atlas board has jumper  which will redirect accesses
> from “Bootcode” range to either “Monitor flash” (0x1e000000) or the upper
> 4MB of “System flash” (0x1dc00000) based on jumper settings. if my kmc
> board have some jumper like this, can I redirect the start address.
>
> Of course, what is really happening there is that the Atlas boot ROM has a
> vector at 0x1fc00000 which reads the jumper and jumps to one address or the
> other depending on the jumper setting. If you control what is in ROM at
> 0x1fc00000 and you have a software-readable jumper on your KMC board, you
> can do the same thing.
>
>           Regards,
>
>           Kevin K.
>
>

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Re: in mips how to change the start address to the new second boot loader ?

[Geert Uytterhoeven]

On Tue, Apr 21, 2009 at 15:46, nagalakshmi veeramallu
<lucky.veeramallu@gmail.com> wrote:
> hi,
>          --          if we set environmental variable “start” as “go
> new_address”, will it go directly to the new bootloader in the next
> power-on.
> what about using system environmental "start" ,can you tell me at which
> context after power on environmental variables come onto picture.

Environment variables are parsed by the boot loader, whose code resides at,
guess what, 0x1fc00000...

> On Tue, Apr 21, 2009 at 6:55 PM, Kevin D. Kissell <kevink@paralogos.com>
> wrote:
>>
>> nagalakshmi veeramallu wrote:
>>
>> -           Mips atlas board has jumper  which will redirect accesses from
>> “Bootcode” range to either “Monitor flash” (0x1e000000) or the upper 4MB of
>> “System flash” (0x1dc00000) based on jumper settings. if my kmc board have
>> some jumper like this, can I redirect the start address.
>>
>> Of course, what is really happening there is that the Atlas boot ROM has a
>> vector at 0x1fc00000 which reads the jumper and jumps to one address or the
>> other depending on the jumper setting. If you control what is in ROM at
>> 0x1fc00000 and you have a software-readable jumper on your KMC board, you
>> can do the same thing.
>>
>>           Regards,
>>
>>           Kevin K.
>>
>
>



-- 
Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds

Re: in mips how to change the start address to the new second boot loader ?

[Geert Uytterhoeven]

On Tue, Apr 21, 2009 at 15:46, nagalakshmi veeramallu
<lucky.veeramallu@gmail.com> wrote:
> hi,
>          --          if we set environmental variable “start” as “go
> new_address”, will it go directly to the new bootloader in the next
> power-on.
> what about using system environmental "start" ,can you tell me at which
> context after power on environmental variables come onto picture.

Environment variables are parsed by the boot loader, whose code resides at,
guess what, 0x1fc00000...

> On Tue, Apr 21, 2009 at 6:55 PM, Kevin D. Kissell <kevink@paralogos.com>
> wrote:
>>
>> nagalakshmi veeramallu wrote:
>>
>> -           Mips atlas board has jumper  which will redirect accesses from
>> “Bootcode” range to either “Monitor flash” (0x1e000000) or the upper 4MB of
>> “System flash” (0x1dc00000) based on jumper settings. if my kmc board have
>> some jumper like this, can I redirect the start address.
>>
>> Of course, what is really happening there is that the Atlas boot ROM has a
>> vector at 0x1fc00000 which reads the jumper and jumps to one address or the
>> other depending on the jumper setting. If you control what is in ROM at
>> 0x1fc00000 and you have a software-readable jumper on your KMC board, you
>> can do the same thing.
>>
>>           Regards,
>>
>>           Kevin K.
>>
>
>



-- 
Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds

Re: in mips how to change the start address to the new second boot loader ?

[nagalakshmi veeramallu]

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Hi,
will this approach work? if i used "start" environmental variable will it go
to new boot loader address directly.

Regards,
Lucky


On Tue, Apr 21, 2009 at 7:40 PM, Geert Uytterhoeven <geert@linux-m68k.org>wrote:

> On Tue, Apr 21, 2009 at 15:46, nagalakshmi veeramallu
> <lucky.veeramallu@gmail.com> wrote:
> > hi,
> >          --          if we set environmental variable “start” as “go
> > new_address”, will it go directly to the new bootloader in the next
> > power-on.
> > what about using system environmental "start" ,can you tell me at which
> > context after power on environmental variables come onto picture.
>
> Environment variables are parsed by the boot loader, whose code resides at,
> guess what, 0x1fc00000...
>
> > On Tue, Apr 21, 2009 at 6:55 PM, Kevin D. Kissell <kevink@paralogos.com>
> > wrote:
> >>
> >> nagalakshmi veeramallu wrote:
> >>
> >> -           Mips atlas board has jumper  which will redirect accesses
> from
> >> “Bootcode” range to either “Monitor flash” (0x1e000000) or the upper 4MB
> of
> >> “System flash” (0x1dc00000) based on jumper settings. if my kmc board
> have
> >> some jumper like this, can I redirect the start address.
> >>
> >> Of course, what is really happening there is that the Atlas boot ROM has
> a
> >> vector at 0x1fc00000 which reads the jumper and jumps to one address or
> the
> >> other depending on the jumper setting. If you control what is in ROM at
> >> 0x1fc00000 and you have a software-readable jumper on your KMC board,
> you
> >> can do the same thing.
> >>
> >>           Regards,
> >>
> >>           Kevin K.
> >>
> >
> >
>
>
>
> --
> Gr{oetje,eeting}s,
>
>                                                Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 --
> geert@linux-m68k.org
>
> In personal conversations with technical people, I call myself a hacker.
> But
> when I'm talking to journalists I just say "programmer" or something like
> that.
>                                                            -- Linus
> Torvalds
>

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Re: in mips how to change the start address to the new second boot loader ?

[nagalakshmi veeramallu]

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Hi,
will this approach work? if i used "start" environmental variable will it go
to new boot loader address directly.

Regards,
Lucky


On Tue, Apr 21, 2009 at 7:40 PM, Geert Uytterhoeven <geert@linux-m68k.org>wrote:

> On Tue, Apr 21, 2009 at 15:46, nagalakshmi veeramallu
> <lucky.veeramallu@gmail.com> wrote:
> > hi,
> >          --          if we set environmental variable “start” as “go
> > new_address”, will it go directly to the new bootloader in the next
> > power-on.
> > what about using system environmental "start" ,can you tell me at which
> > context after power on environmental variables come onto picture.
>
> Environment variables are parsed by the boot loader, whose code resides at,
> guess what, 0x1fc00000...
>
> > On Tue, Apr 21, 2009 at 6:55 PM, Kevin D. Kissell <kevink@paralogos.com>
> > wrote:
> >>
> >> nagalakshmi veeramallu wrote:
> >>
> >> -           Mips atlas board has jumper  which will redirect accesses
> from
> >> “Bootcode” range to either “Monitor flash” (0x1e000000) or the upper 4MB
> of
> >> “System flash” (0x1dc00000) based on jumper settings. if my kmc board
> have
> >> some jumper like this, can I redirect the start address.
> >>
> >> Of course, what is really happening there is that the Atlas boot ROM has
> a
> >> vector at 0x1fc00000 which reads the jumper and jumps to one address or
> the
> >> other depending on the jumper setting. If you control what is in ROM at
> >> 0x1fc00000 and you have a software-readable jumper on your KMC board,
> you
> >> can do the same thing.
> >>
> >>           Regards,
> >>
> >>           Kevin K.
> >>
> >
> >
>
>
>
> --
> Gr{oetje,eeting}s,
>
>                                                Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 --
> geert@linux-m68k.org
>
> In personal conversations with technical people, I call myself a hacker.
> But
> when I'm talking to journalists I just say "programmer" or something like
> that.
>                                                            -- Linus
> Torvalds
>

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Re: in mips how to change the start address to the new second boot loader ?

[Kevin D. Kissell]

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Either you have control of what is in the boot ROM at 0x1fc00000 or you
do not.  If you have control, you can do whatever you like - read
switches, reference environment variables stored in FLASH somehow,
whatever - to decide how you want to proceed.  But it's your problem to
know where the switches are, where and how the NVRAM is to be accessed
and interpreted, etc.  If you do not have control over the code at
0x1fc00000, you need to find out what options it provides, either by
RTFM or by reverse engineering.

There is no magic here, just low-level, brute-force programming.

          Regards,

          Kevin K.

nagalakshmi veeramallu wrote:
> Hi,
> will this approach work? if i used "start" environmental variable will
> it go to new boot loader address directly.
>
>
> Regards,
> Lucky
>
>
> On Tue, Apr 21, 2009 at 7:40 PM, Geert Uytterhoeven
> <geert@linux-m68k.org <mailto:geert@linux-m68k.org>> wrote:
>
>     On Tue, Apr 21, 2009 at 15:46, nagalakshmi veeramallu
>     <lucky.veeramallu@gmail.com <mailto:lucky.veeramallu@gmail.com>>
>     wrote:
>     > hi,
>     >          --          if we set environmental variable “start” as “go
>     > new_address”, will it go directly to the new bootloader in the next
>     > power-on.
>     > what about using system environmental "start" ,can you tell me
>     at which
>     > context after power on environmental variables come onto picture.
>
>     Environment variables are parsed by the boot loader, whose code
>     resides at,
>     guess what, 0x1fc00000...
>
>     > On Tue, Apr 21, 2009 at 6:55 PM, Kevin D. Kissell
>     <kevink@paralogos.com <mailto:kevink@paralogos.com>>
>     > wrote:
>     >>
>     >> nagalakshmi veeramallu wrote:
>     >>
>     >> -           Mips atlas board has jumper  which will redirect
>     accesses from
>     >> “Bootcode” range to either “Monitor flash” (0x1e000000) or the
>     upper 4MB of
>     >> “System flash” (0x1dc00000) based on jumper settings. if my kmc
>     board have
>     >> some jumper like this, can I redirect the start address.
>     >>
>     >> Of course, what is really happening there is that the Atlas
>     boot ROM has a
>     >> vector at 0x1fc00000 which reads the jumper and jumps to one
>     address or the
>     >> other depending on the jumper setting. If you control what is
>     in ROM at
>     >> 0x1fc00000 and you have a software-readable jumper on your KMC
>     board, you
>     >> can do the same thing.
>     >>
>     >>           Regards,
>     >>
>     >>           Kevin K.
>     >>
>     >
>     >
>
>
>
>     --
>     Gr{oetje,eeting}s,
>
>                                                    Geert
>
>     --
>     Geert Uytterhoeven -- There's lots of Linux beyond ia32 --
>     geert@linux-m68k.org <mailto:geert@linux-m68k.org>
>
>     In personal conversations with technical people, I call myself a
>     hacker. But
>     when I'm talking to journalists I just say "programmer" or
>     something like that.
>                                                                --
>     Linus Torvalds
>
>


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Re: in mips how to change the start address to the new second boot loader ?

[Florian Fainelli]

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Hi,

Le Tuesday 21 April 2009 16:20:48 nagalakshmi veeramallu, vous avez écrit :
> Hi,
> will this approach work? if i used "start" environmental variable will it
> go to new boot loader address directly.

Yamon also has a start environnment variable which is used to do something 
without user-intervention. I do not know cmon, but assuming it behaves 
similarly, you might want to set the start variable to something like: "go 
0xdeadbeef". And make sure your code starts at 0xdeadbeef for instance.

That way, you keep cmon on the flash and use it to jump to an arbitrary 
location, which is anyway, what would be done if you used cmon to boot Linux 
for instance.

>
> Regards,
> Lucky
>
> On Tue, Apr 21, 2009 at 7:40 PM, Geert Uytterhoeven 
<geert@linux-m68k.org>wrote:
> > On Tue, Apr 21, 2009 at 15:46, nagalakshmi veeramallu
> >
> > <lucky.veeramallu@gmail.com> wrote:
> > > hi,
> > >          --          if we set environmental variable “start” as “go
> > > new_address”, will it go directly to the new bootloader in the next
> > > power-on.
> > > what about using system environmental "start" ,can you tell me at which
> > > context after power on environmental variables come onto picture.
> >
> > Environment variables are parsed by the boot loader, whose code resides
> > at, guess what, 0x1fc00000...
> >
> > > On Tue, Apr 21, 2009 at 6:55 PM, Kevin D. Kissell
> > > <kevink@paralogos.com>
> > >
> > > wrote:
> > >> nagalakshmi veeramallu wrote:
> > >>
> > >> -           Mips atlas board has jumper  which will redirect accesses
> >
> > from
> >
> > >> “Bootcode” range to either “Monitor flash” (0x1e000000) or the upper
> > >> 4MB
> >
> > of
> >
> > >> “System flash” (0x1dc00000) based on jumper settings. if my kmc board
> >
> > have
> >
> > >> some jumper like this, can I redirect the start address.
> > >>
> > >> Of course, what is really happening there is that the Atlas boot ROM
> > >> has
> >
> > a
> >
> > >> vector at 0x1fc00000 which reads the jumper and jumps to one address
> > >> or
> >
> > the
> >
> > >> other depending on the jumper setting. If you control what is in ROM
> > >> at 0x1fc00000 and you have a software-readable jumper on your KMC
> > >> board,
> >
> > you
> >
> > >> can do the same thing.
> > >>
> > >>           Regards,
> > >>
> > >>           Kevin K.
> >
> > --
> > Gr{oetje,eeting}s,
> >
> >                                                Geert
> >
> > --
> > Geert Uytterhoeven -- There's lots of Linux beyond ia32 --
> > geert@linux-m68k.org
> >
> > In personal conversations with technical people, I call myself a hacker.
> > But
> > when I'm talking to journalists I just say "programmer" or something like
> > that.
> >                                                            -- Linus
> > Torvalds



-- 
Best regards, Florian Fainelli
Email : florian@openwrt.org
http://openwrt.org
-------------------------------

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