[coreboot] [RFC] flashrom: sector-based flashing

[Carl-Daniel Hailfinger]

Hi,

flashrom hasn't seen any major design changes in the last few months and
most chips still perform whole-chip erase instead of sector-based erase.

I'd like to introduce a function which takes a range and rounds the
start and the end of the range to the nearest block boundary.
void roundup(struct flashchip *flash, int *startpos, int *endpos);

Take an example 256 kByte flash chip with the following sector layout:
0x00000-0x0ffff 64kB block
0x10000-0x1ffff 64kB block
0x20000-0x2ffff 64kB block
0x30000-0x37fff 32kB block
0x38000-0x3bfff 16kB block
0x3c000-0x3dfff 8kB block
0x3e000-0x3efff 4kB block
0x3f000-0x3ffff 4kB block

startpos=0x38123;
endpos=0x3e005;
roundup(flash, &startpos, &endpos);
//results follow:
//startpos=0x38000;
//endpos=0x3efff;

That way, it is easily possible to check whether a given range can be
handled by sector-based erase and write.
You can use that result to tell the user that a range outside the
intended range will get flashed. It is also possible to refuse flashing
in that case.

Since the function will be generic and take a struct flashchip, there's
no need to store a pointer to it with each chip and you can call the
generic one from anywhere.

What do you think?

Regards,
Carl-Daniel

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