Re: [ECOS] HAL_FLASH_CACHES_XXX

[Jonathan Larmour <jifl at eCosCentric dot com>]

Jay Foster wrote:
> The comments for the HAL_FLASH_CACHES_ON and HAL_FLASH_CACHES_OFF macros in
> flash.h state that these macros must be called with interrupts disabled.
> This seems to make sense.  However, code inspection reveals that they are
> called with interrupts enabled.  I see no interrupt disabling in
> flash_dev_query(), flash_erase(), flash_program(), flash_lock() and
> flash_unlock() or in the functions that call these.  Am I missing something
> here?  It seems unlikely that if this were a real problem that it would have
> gone unoticed for very long.

Only in as much as that the caller should disable interrupts if needed.

The comment in flash.h is slightly exaggerating - it's generally true in 
most cases people use it, but it's possible to use this safely with 
interrupts enabled if you are running out of RAM or somewhere that isn't 
flash anyway (such that an interrupt can't touch flash, although also that 
it won't go and re-enable the cache either!). Saying you "can't" is safer, 
but actually forcing ints off is unfriendly.

The flash layer was originally only written to be used with RedBoot, not 
ecos, and this is a throwback to then, and something that will have to be 
solved properly throughout the package, not just here. And then we could 
also document the API properly too :-).

Jifl
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