[U-Boot-Users] Problem with flash cfi legacy mode

[U-Boot-Users] Problem with flash cfi legacy mode

[Tor Krill]

Hi,

Im working on adding support for our board to u-boot.

I use legacy flash mode for our boot-flash. I however have some problems
with it.

When using jedec probe to identify our flash. Im unable to do so with our
16bit device-id. In my opinion it seems like this actually wont work(?)

cmdset_amd_read_jedec_ids uses _one_ flash_read_uchar call to read out
the device id(, if its not an amd extended one). The only way i could
get this to work with our flash was to only put the lower 8bit in the
dev_id field when adding an entry to the jedec_table.

Further on it seems like CFI_CMDSET_AMD_LEGACY is unsupported in
flash_write_cfibuffer.

/Tor

[U-Boot-Users] Problem with flash cfi legacy mode

[Michael Schwingen]

Tor Krill wrote:
> Im working on adding support for our board to u-boot.
>
> I use legacy flash mode for our boot-flash. I however have some problems
> with it.
>
> When using jedec probe to identify our flash. Im unable to do so with our
> 16bit device-id. In my opinion it seems like this actually wont work(?)
>
> cmdset_amd_read_jedec_ids uses _one_ flash_read_uchar call to read out
> the device id(, if its not an amd extended one). The only way i could
> get this to work with our flash was to only put the lower 8bit in the
> dev_id field when adding an entry to the jedec_table.
>   
Hm - right. You are probably the first one to use that code on a 16-bit 
non-CFI flash - for 16-bit flashs, the read will need to be changed, but 
I am not sure how exactly - I think we may need separate code depending 
on info->chipwidth, because 8-bit flashs only have an 8-bit ID.
> Further on it seems like CFI_CMDSET_AMD_LEGACY is unsupported in
> flash_write_cfibuffer.
>   
Right. Setting info->buffer_size = 1 in jedec_flash.c/fill_info() should 
make sure that part of code is never executed.

cu
Michael

[U-Boot-Users] Problem with flash cfi legacy mode

[Tor Krill]

On 3/14/2008, "Michael Schwingen" <rincewind@discworld.dascon.de> wrote:

>Tor Krill wrote:
>> Im working on adding support for our board to u-boot.
>>
>> I use legacy flash mode for our boot-flash. I however have some problems
>> with it.
>>
>> When using jedec probe to identify our flash. Im unable to do so with our
>> 16bit device-id. In my opinion it seems like this actually wont work(?)
>>
>> cmdset_amd_read_jedec_ids uses _one_ flash_read_uchar call to read out
>> the device id(, if its not an amd extended one). The only way i could
>> get this to work with our flash was to only put the lower 8bit in the
>> dev_id field when adding an entry to the jedec_table.
>>
>Hm - right. You are probably the first one to use that code on a 16-bit
>non-CFI flash - for 16-bit flashs, the read will need to be changed, but
>I am not sure how exactly - I think we may need separate code depending
>on info->chipwidth, because 8-bit flashs only have an 8-bit ID.

Can one asume that a chip with chipwidht 16 always has an ID of 16bit?
And how does AMD expanded 3byte id mode fit?  If its safe to just change
the read   it should be trivial to fix(?)

>> Further on it seems like CFI_CMDSET_AMD_LEGACY is unsupported in
>> flash_write_cfibuffer.
>>
>Right. Setting info->buffer_size = 1 in jedec_flash.c/fill_info() should
>make sure that part of code is never executed.

Ok, i just skipped CFG_FLASH_USE_BUFFER_WRITE instead. That solved it for
me.

/Tor

[U-Boot-Users] Problem with flash cfi legacy mode

[Michael Schwingen]

Tor Krill wrote:
>> Hm - right. You are probably the first one to use that code on a 16-bit
>> non-CFI flash - for 16-bit flashs, the read will need to be changed, but
>> I am not sure how exactly - I think we may need separate code depending
>> on info->chipwidth, because 8-bit flashs only have an 8-bit ID.
>>     
>
> Can one asume that a chip with chipwidht 16 always has an ID of 16bit?
> And how does AMD expanded 3byte id mode fit?  If its safe to just change
> the read   it should be trivial to fix(?)
>   
I think it should be OK to use 16-bit reads if info->chipwidth==2.

cu
Michael