[flashrom] Hardware Sequencing vs Software Sequencing

[Carl-Daniel Hailfinger]

Hi John,

On 30.03.2010 02:47, john warwick wrote:
> I was looking through the code, and see that flashrom is using software sequencing. Is there any reason for software sequencing to be chosen instead of hardware sequencing?
>   

Assuming that you're talking about the Intel ICH SPI code, here's the
info I have:
Yes, there are multiple reasons why hardware sequencing is not supported:
- You can't reflash the complete chip, just the region for the current
(BIOS) descriptor.
- You're unable to read the whole chip.
- If you exchange the flash chip, write/erase may fail in random ways.
- Crossflashing/hotflashing is pretty much impossible.
- Nobody implemented it.


> Are there any restrictions imposed for hardware sequencing?
>   

Please see above.

Of course, if you're willing to contribute code for ICH SPI hardware
sequencing, we'll be glad to review and merge it. Please be warned that
this is a rather difficult task, especially because flashrom assumes
that a flash chip can be accessed in full and you'll either have to
emulate this or change flashrom safety checks and code flow in a few
strategic places.

Regards,
Carl-Daniel

-- 
http://www.hailfinger.org/