Re: [ECOS] flash size calculation

[Jonathan Larmour <jlarmour at redhat dot com>]

Christoph Csebits wrote:
> 
> hi
> 
> in the most platforms start-address and end-address
> of the flash devices are calculated like the following:
> 
> flash_info.start = (void *)CYGNUM_FLASH_BASE;
> flash_info.end = (void *)(CYGNUM_FLASH_BASE+ (FLASH_NUM_REGIONS
>         * FLASH_BLOCK_SIZE * CYGNUM_FLASH_INTERLEAVE * CYGNUM_FLASH_SERIES));
> 
> Supposed i have an 8MB flash starting at 0xFF800000:
> flash_info.start = 0xFF800000
> flash_info.end = 0x00000000 (overflow).
> 
> Is it sufficient to decrement the end address by one?

Probably not good: looking at redboot's load_flash_config() function, it
uses the flash_end (set from flash_info.end) to calculate the base for the
flash config. But that should be aligned to a flash block.

This is an oversight in the flash code. Patches welcome :-). Probably the
thing to do is make the flash end address be an unsigned long long, and
change all the types that use it accordingly (like flash_end).

Jifl
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