[U-Boot-Users] Where in u-boot is the RAM "Mode Register" programmed?

[U-Boot-Users] Where in u-boot is the RAM "Mode Register" programmed?

[Bjook]

 

My question is: Where in u-boot is the RAM "Mode Register" programmed?
Also, is my PCB usable with its mangled RAM address lines?

 

I am using the "at91rm9200dk" configuration with a couple of changes.  

I ran into problems with the RAM.  We are using a 64Mbit MT48LC2M32 instead
of the 128Mbit MT48LC8M32 which should not be a problem.  Same chip except
for half the capacity.

The only problem is my hardware layout guy decided to mangle the address
lines when he connected the RAM to the ARM processor.  His reasoning was
that a RAM address is a RAM address is a RAM address.  If you always access
the RAM from the Arm chip then the mangled lines will always get decoded and
you will get the correct data value.

 

What the layout guy did not realize was that this RAM has a Mode Register
that needs to be programmed.  Where does this happen in u-boot?  If I can
find out where it is set then I can decode the mangled address lines and put
the proper value in.

Also I will set the "burst read" to 0.

 

 

Do you think this situation salvageable?  A10 is the same because it is a
special line but I may need to jumper A8 and A9 since it looks like they are
only used to program the address register.

 

The mangled lines are as follows

Normal -> Mangled

A0 -> A1

A1 -> A3

A2 -> A2

A3 -> A11

A4 -> A7

A5 -> A8

A6 -> A6

A7 -> A4

A8 -> A9

A9 -> A0

A10 -> A10

 

Next time I will fix the mangled lines but I really need to prove out my
design on my current 50 boards since another spin takes around a month
(because of BGA chips).

 

-Bjook

 

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[U-Boot-Users] Where in u-boot is the RAM "Mode Register"programmed?

[Ulf Samuelsson]

  ----- Original Message ----- 
  From: Bjook 
  To: u-boot-users at lists.sourceforge.net 
  Sent: Thursday, March 22, 2007 10:56 PM
  Subject: [U-Boot-Users] Where in u-boot is the RAM "Mode Register"programmed?


   

  My question is: Where in u-boot is the RAM "Mode Register" programmed?  Also, is my PCB usable with its mangled RAM address lines?

   

  I am using the "at91rm9200dk" configuration with a couple of changes.  

  I ran into problems with the RAM.  We are using a 64Mbit MT48LC2M32 instead of the 128Mbit MT48LC8M32 which should not be a problem.  Same chip except for half the capacity.

  The only problem is my hardware layout guy decided to mangle the address lines when he connected the RAM to the ARM processor.  His reasoning was that a RAM address is a RAM address is a RAM address.  If you always access the RAM from the Arm chip then the mangled lines will always get decoded and you will get the correct data value.

   

  What the layout guy did not realize was that this RAM has a Mode Register that needs to be programmed.  Where does this happen in u-boot?  If I can find out where it is set then I can decode the mangled address lines and put the proper value in.

  Also I will set the "burst read" to 0.

   

   

  Do you think this situation salvageable?  A10 is the same because it is a special line but I may need to jumper A8 and A9 since it looks like they are only used to program the address register.

   

  The mangled lines are as follows

  Normal -> Mangled

  A0 -> A1

  A1 -> A3

  A2 -> A2

  A3 -> A11

  A4 -> A7

  A5 -> A8

  A6 -> A6

  A7 -> A4

  A8 -> A9

  A9 -> A0

  A10 -> A10

   

  Next time I will fix the mangled lines but I really need to prove out my design on my current 50 boards since another spin takes around a month (because of BGA chips).

   

  -Bjook


You need to know what flash memory you are using.
If you are using a dataflash, then it takes place in dataflashboot.bin, not in U-Boot.
Otherwise you have to look at the cpu/arm920t/at91rm9200 directory.
Should be an assembler file there. Dont remember its name.


Best Regards
Ulf Samuelsson 
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[U-Boot-Users] Where in u-boot is the RAM "Mode Register" programmed?

[Jerry Van Baren]

Bjook wrote:
>  

[snip]

> The only problem is my hardware layout guy decided to mangle the address 
> lines when he connected the RAM to the ARM processor.  His reasoning was 
> that a RAM address is a RAM address is a RAM address.  If you always 
> access the RAM from the Arm chip then the mangled lines will always get 
> decoded and you will get the correct data value.
> 
> What the layout guy did not realize was that this RAM has a Mode 
> Register that needs to be programmed.  Where does this happen in 
> u-boot?  If I can find out where it is set then I can decode the mangled 
> address lines and put the proper value in.
> 
> Also I will set the ?burst read? to 0.
> 
> Do you think this situation salvageable?  A10 is the same because it is 
> a special line but I may need to jumper A8 and A9 since it looks like 
> they are only used to program the address register.

[snip]

> Next time I will fix the mangled lines but I really need to prove out my 
> design on my current 50 boards since another spin takes around a month 
> (because of BGA chips).
> 
> -Bjook

Oooooo, you get this working he owes you a lifetime supply of beer. 
Make him pay for a long time, don't drink it all at once. ;-)

grep is your friend and start.S is the place to start.
/u-boot/cpu/arm920t/at91rm9200/lowlevel_init.S

I'm not familiar with the ARM(r) memory controller.  If it just does 
address and data (looks like it), it should be salvageable (if so, it 
probably isn't worth re-laying out the board unless you have other 
problems).  The initialization is a stream of defines of (address / 
data) pairs at the labels SMRDATA and SMRDATA1.  You will have to warp 
the addresses, but it probably will work.

Good luck,
gvb