[U-Boot] Handling dual die and single die flash on same board

[U-Boot] Handling dual die and single die flash on same board

[Chris Packham]

Hi,

I've run into a situation with a new design and I could use some pointers.

Our hardware designers have built prototypes with different flash
configurations. One possible configuration is a dual die 2x32MB the
other is a single die 1x64MB.

My u-boot config is currently setup for the 2x32MB case i.e.
CONFIG_SYS_MAX_FLASH_BANKS = 2, CONFIG_SYS_FLASH_BANKS_LIST = {base,
base+32MB}. The problem with this is that when flash_get_size is called
on the 1x64 chip it discovers the same chip the 2nd time around and
promptly walks off the end of the memory area I have allocated for it.

Is there any existing way to make the cfi_flash driver handle this
situation for me?

Thanks,
Chris Packham

[U-Boot] Handling dual die and single die flash on same board

[Stefan Roese]

Hi Chris,

On Tuesday 07 September 2010 19:05:46 Chris Packham wrote:
> I've run into a situation with a new design and I could use some pointers.
> 
> Our hardware designers have built prototypes with different flash
> configurations. One possible configuration is a dual die 2x32MB the
> other is a single die 1x64MB.
> 
> My u-boot config is currently setup for the 2x32MB case i.e.
> CONFIG_SYS_MAX_FLASH_BANKS = 2, CONFIG_SYS_FLASH_BANKS_LIST = {base,
> base+32MB}. The problem with this is that when flash_get_size is called
> on the 1x64 chip it discovers the same chip the 2nd time around and
> promptly walks off the end of the memory area I have allocated for it.
> 
> Is there any existing way to make the cfi_flash driver handle this
> situation for me?

I just recently sent a patchset for the CFI driver that could help to handle 
such a situation. Here the most interesting patch:

http://www.mail-archive.com/u-boot at lists.denx.de/msg37234.html

I would suggest to set CONFIG_SYS_MAX_FLASH_BANKS_DETECT to 2 and then add 
some board specific code to determine the real bank count and set 
cfi_flash_num_flash_banks accordingly.

Hope this helps.

Cheers,
Stefan

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[U-Boot] Handling dual die and single die flash on same board

[Chris Packham]

On 07/09/10 10:26, Stefan Roese wrote:
> Hi Chris,
> 
> On Tuesday 07 September 2010 19:05:46 Chris Packham wrote:
>> My u-boot config is currently setup for the 2x32MB case i.e.
>> CONFIG_SYS_MAX_FLASH_BANKS = 2, CONFIG_SYS_FLASH_BANKS_LIST = {base,
>> base+32MB}. The problem with this is that when flash_get_size is called
>> on the 1x64 chip it discovers the same chip the 2nd time around and
>> promptly walks off the end of the memory area I have allocated for it.
>>
>> Is there any existing way to make the cfi_flash driver handle this
>> situation for me?
> 
> I just recently sent a patchset for the CFI driver that could help to handle 
> such a situation. Here the most interesting patch:
> 
> http://www.mail-archive.com/u-boot at lists.denx.de/msg37234.html
> 
> I would suggest to set CONFIG_SYS_MAX_FLASH_BANKS_DETECT to 2 and then add 
> some board specific code to determine the real bank count and set 
> cfi_flash_num_flash_banks accordingly.
> 

Thanks for the pointers. For now I've followed the example in tqm834x.c.
I've done it in such a way that when we next pull in upstream u-boot it
should co-exists nicely with your proposed patch.