[U-Boot-Users] porting to custom at 91 board

[U-Boot-Users] porting to custom at 91 board

[Z.N.]

Dear developers!

As some advised, instead of trying to write a boot loader for a custom
AT91 board, I wanted to use the loader.bin and u-boot.bin from ATMEL.

However, after transferring loader.bin, the 'C'-s appear, however, I
cannot transfer u-boot.bin, because Hyper terminal displays some "Error
limit exceeded" message. (I've also tried with minicom, it gives a
couple of NAK messages when transferring u-boot.bin).

What can be the error?

My board is more or less the same as at19rm9200dk, however it has only 1
chip of 16 bit SDRAM connected instead of 2 chips (so the data bus is
only 16 bits wide, and memory timings are different). Can this cause a
problem?

My alternate question is, how to port u-boot, so that I can start it in
RAM with the above configuration (I've got a small boot loader done in
assembly, which is loaded from SPI on startup. So I could store u-boot
in the SPI flash, and load it to RAM from there on startup by my small
boot loader. how to do this? eg. where to load the u-boot image in RAM?
I guess I have to also adjust the SDRAM setup and timings which are
differing from the atmel DK.). have anyone ported u-boot to such a
configuration?

I'd be grateful if you could give me any pointers on this problem.

Best Regards,
Zo

[U-Boot-Users] porting to custom at 91 board

[Wolfgang Denk]

In message <1100993019.6511.10.camel@localhost> you wrote:
> 
> As some advised, instead of trying to write a boot loader for a custom
> AT91 board, I wanted to use the loader.bin and u-boot.bin from ATMEL.

Even better just use U-Boot and forget about loader.bin ...

> My alternate question is, how to port u-boot, so that I can start it in
> RAM with the above configuration (I've got a small boot loader done in
> assembly, which is loaded from SPI on startup. So I could store u-boot
> in the SPI flash, and load it to RAM from there on startup by my small
> boot loader. how to do this? eg. where to load the u-boot image in RAM?
> I guess I have to also adjust the SDRAM setup and timings which are
> differing from the atmel DK.). have anyone ported u-boot to such a
> configuration?

Instead of doing all  this  which  is  really  non-trivial  and  also
ineffficient you could just boot from flash. I've just checked in the
necessary patches for the AT91RM9200DK and CMC_PU2 boards ...

Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
Thought for the day: What if there were no hypothetical situations?

[U-Boot-Users] porting to custom at 91 board

[Z.N.]

Hi!
> > As some advised, instead of trying to write a boot loader for a custom
> > AT91 board, I wanted to use the loader.bin and u-boot.bin from ATMEL.
> 
> Even better just use U-Boot and forget about loader.bin ...
ok, that wlll be easy :)

> > My alternate question is, how to port u-boot, so that I can start it in
> > RAM with the above configuration (I've got a small boot loader done in
> > assembly, which is loaded from SPI on startup. So I could store u-boot
> > in the SPI flash, and load it to RAM from there on startup by my small
> > boot loader. how to do this? eg. where to load the u-boot image in RAM?
> > I guess I have to also adjust the SDRAM setup and timings which are
> > differing from the atmel DK.). have anyone ported u-boot to such a
> > configuration?
> 
> Instead of doing all  this  which  is  really  non-trivial  and  also
> ineffficient you could just boot from flash. I've just checked in the
> necessary patches for the AT91RM9200DK and CMC_PU2 boards ...

What do you mean by booting from flash? Since I've got only an SPI flash
connected, U-boot has to be taken apart, since the AT91 internal boot
loader can only load 16KB of code from the flash into the internal
processor SRAM. So what is needed is some code for the SPI flash, which
boots the processor, and reads the rest of u-boot from the SPI flash
into the initialized SDRAM.

Does booting from flash solve the SDRAM initialization problem? (I mean
the SDRAM on my board needs worst case memory timings, and I guess the
atmel DK memory setup code does not use worst case timings..)

Thank you all for your help.

Best regards:Zo

[U-Boot-Users] porting to custom at 91 board

[Wolfgang Denk]

In message <1101030722.6343.6.camel@localhost> you wrote:
>
> > Instead of doing all  this  which  is  really  non-trivial  and  also
> > ineffficient you could just boot from flash. I've just checked in the
> > necessary patches for the AT91RM9200DK and CMC_PU2 boards ...
> 
> What do you mean by booting from flash? Since I've got only an SPI flash

I mean booting from the  NOR  flash  attached  to  any  halfway  sane
design.

> connected, U-boot has to be taken apart, since the AT91 internal boot
> loader can only load 16KB of code from the flash into the internal
> processor SRAM. So what is needed is some code for the SPI flash, which

No - you are not restricted to booting from SPI DataFlash,  and  it's
not 16 kB. The AT91RM9200 supports 3 boot methods:

1) Pulling the first 12 kilobytes of a SPI DataFlash memory part into
   internal SRAM and executing it.

2) If #1 fails, pulling the first 12 kilobytes of a serial I2C EEPROM
   into internal SRAM and executing it.

3) If #2 fails, executing code from an attached NOR flash device.

What we use is 3) as there is NOR flash on both the AT91RM9200DK  and
the CMC_PU2 boards, so this is the fastest way to boot a system.


If you don't have any nor flash, you  should  (1)  complain  at  your
hardware designers and (2) make sure that CONFIG_BOOTBINFUNC is _not_
defned in your board config file.

> boots the processor, and reads the rest of u-boot from the SPI flash
> into the initialized SDRAM.
> 
> Does booting from flash solve the SDRAM initialization problem? (I mean

Yes, of course, because you can include regular  initialization  code
for the memory controller.


Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
"Wagner's music is better than it sounds."               - Mark Twain

[U-Boot-Users] porting to custom at 91 board

[Steven Scholz]

Wolfgang Denk wrote:

> Instead of doing all  this  which  is  really  non-trivial  and  also
> ineffficient you could just boot from flash. I've just checked in the
> necessary patches for the AT91RM9200DK and CMC_PU2 boards ...

Am I supposed to rewrite my AT91RM9200 SoC patch then?

--
Steven

[U-Boot-Users] porting to custom at 91 board

[Wolfgang Denk]

In message <41A1B7CB.7070406@imc-berlin.de> you wrote:
> 
> > Instead of doing all  this  which  is  really  non-trivial  and  also
> > ineffficient you could just boot from flash. I've just checked in the
> > necessary patches for the AT91RM9200DK and CMC_PU2 boards ...
> 
> Am I supposed to rewrite my AT91RM9200 SoC patch then?

Argh.. I knew that there was something pending.

Can you do it? Otherwise I will try (because it was  my  action  that
caused the problem), but this may take some time...

Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
What we anticipate seldom occurs;  what  we  least  expect  generally
happens.                                          - Bengamin Disraeli

[U-Boot-Users] porting to custom at 91 board

[Steven Scholz]

Wolfgang Denk wrote:

> In message <41A1B7CB.7070406@imc-berlin.de> you wrote:
> 
>>>Instead of doing all  this  which  is  really  non-trivial  and  also
>>>ineffficient you could just boot from flash. I've just checked in the
>>>necessary patches for the AT91RM9200DK and CMC_PU2 boards ...
>>
>>Am I supposed to rewrite my AT91RM9200 SoC patch then?
> 
> 
> Argh.. I knew that there was something pending.
> 
> Can you do it? Otherwise I will try (because it was  my  action  that
> caused the problem), but this may take some time...

Are we talking about hours, days, month?
I first have to look what exactly you change.
But I'll try.


-- 
Steven Scholz

[U-Boot-Users] porting to custom at 91 board

[Wolfgang Denk]

In message <41A1C9B5.9030709@imc-berlin.de> you wrote:
> 
> > Can you do it? Otherwise I will try (because it was  my  action  that
> > caused the problem), but this may take some time...
> 
> Are we talking about hours, days, month?

Days or weeks.

> I first have to look what exactly you change.
> But I'll try.

Thanks. IOU a beer ...

Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
The word "fit", as I understand it, means "appropriate to a purpose",
and I would say the body of the Dean is supremely appropriate to  the
purpose of sitting around all day and eating big heavy meals.
                                 - Terry Pratchett, _Moving Pictures_