[U-Boot] What is the expected meaning of CONFIG_SYS_NO_FLASH

Stefan Roese stefan.roese at gmail.com
Wed Jun 10 09:18:30 CEST 2015


Hi Chris,

On 10.06.2015 02:02, Chris Packham wrote:
> There is a bit of confusion at $dayjob about when CONFIG_SYS_NO_FLASH
> is used. Initially we thought that this meant I have no parallel NOR
> flash. So a board with only SPI flash would have CONFIG_SYS_NO_FLASH=1
> and CONFIG_SPI_FLASH=1.
>
> Is this understanding correct?

Yes. CONFIG_SYS_NO_FLASH dates back to a time when only parallel NOR 
flash (like CFI NOR) was available. And it definitely is now confusing 
at least. Perhaps it would be good to rename it to 
CONFIG_SYS_NO_PARALLEL_FLASH now.

> I'd like to be able to add a blurb to
> README about how CONFIG_SYS_NO_FLASH should be used.

Thanks, that would be helpful.

> Based on what I
> can tell from the code there seems to be a requirement that if
> !defined(CONFIG_SYS_NO_FLASH) something must implement flash_init(),
> flash_write(), etc as defined in include/flash.h. This could be a
> driver like cfi_flash.c or a board specific implementation.

Yes, this seems to be a correct assumption.

Thanks,
Stefan



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