Change in flashrom[master]: ichspi.c: Check SPI Cycle In-Progress prior start HW Seq

[Nico Huber (Code Review)]

Attention is currently required from: Patrick Georgi, Rizwan Qureshi, Stefan Reinauer, Sridhar Siricilla, Angel Pons, Alex Levin, YH Lin, Martin Roth, Subrata Banik, Caveh Jalali, Tim Wawrzynczak, Nick Vaccaro, Boris Mittelberg.
Nico Huber has posted comments on this change. ( https://review.coreboot.org/c/flashrom/+/61854 )

Change subject: ichspi.c: Check SPI Cycle In-Progress prior start HW Seq
......................................................................

Patch Set 6:

(1 comment)

Patchset:

PS6:
> > A version of this change that takes the applicable context into account
> > (e.g. other waiting loops in this driver, implications when multiple
> > instances would reach this point in the code simultaneously) would be
> > accepted immediately.
>
> I understand that would be a comprehensive fix across flashrom.

Doesn't need to be. All I'm asking for is to keep the whole code sound
and not just the single spot where a check would be added. This could
for instance be a simple

if (REGREAD8(ICH9_REG_HSFS) & HSFS_SCIP)
          return -1;

That would adhere to the datasheet, AFAICT and wouldn't make it look
like we don't know what we are doing (not knowing what we are doing,
for instance, would be writing a program that tries to synchronize
multiple processes but fails to do so properly).

Another solution would be to check the bit once on programmer initiali-
zation and after each transaction.
> However that will still not guarantee that another flashrom like program will wait on the same file/mutex to synchronize the access.
>
> This check on H_SCIP OTOH, which should be adhered by all the programs at the least prevents the program from cancelling out another's transaction. So let us make flashrom compliant with the recommendation.

Then check the bit once in programmer init. That should cover another
previously running program. Multiple, concurrently running programs
are out of the scope of SCIP.