[coreboot] Winflashrom plans

Carl-Daniel Hailfinger c-d.hailfinger.devel.2006 at gmx.net
Wed Jun 16 01:47:30 CEST 2010

Hi Darmawan,

nice to see you're back.
flashrom has its own mailing list and I added it to CC.

On 15.06.2010 21:56, Darmawan Salihun wrote:
> Sorry, I haven't been able to update Winflashrom for more than 3 years now.
> I'm planning to add Windows 7 support next month.


> Therefore, I'm looking for suggestions.
> A bit of Winflashrom background of the currently available Winflashrom
> (at flashrom.org):
> The programming model:
> a. User mode application:
>     - Mostly "pure" flashrom source code recompiled with MinGW.

Current flashrom can be compiled with MinGW and Cygwin, but it doesn't
support any PCI accesses (USB and serial work).

>     - libpci recompiled with MinGW (for PCI access logic). This is
> required because
>        the PCI access functions in the Windows API is not guaranteed
> (marked as obsolete),
>        in Windows XP SP2 and Windows 2003 server back then.

If the PCI access functions are still available in Windows 7, can we
simply ignore the "deprecated" warnings? CF8/CFC accesses from userspace
are not atomic and might cause mixed up PCI accesses.

> b. Device driver:
>     - Provides POSIX mmap() implementation in the kernel, i.e.
>       provides an entrypoint for mmap() function to user mode application.

Please note that we need two types of memory mapping:
sys_physmap_ro_cached() and sys_physmap_rw_uncached(). For example, the
low memory mapping for coreboot tables uses the readonly cached variant,
and any future DMI string access will also use the readonly cached
variant. Any MMIO areas (including flash access) use the uncached rw
variant. Some operating systems do not care at all about cached/uncached
mapping (they simply use the default caching settings of that memory
region), and for those you can use the uncached rw access for both
access types.

>     - Provides direct I/O port access for libpci.
> Well, the reason for these programming model is to reduce the burden
> when moving to newer flash chip support because this programming model
> "preserves" the POSIX API in the user mode application (the device
> driver is generic enough).
> Therefore, "only" the user mode application need to be recompiled to
> support new flash chip.
> Any suggestions on what to change from the current programming model?

Current flashrom already supports PCI device flashing and onboard
flashing on DOS, Linux, FreeBSD, NetBSD, DragonFlyBSD, OpenSolaris, Mac
OS X and a few others.
Please take a look at hwaccess.c and hwaccess.h and physmap.c for things
you might want to change for Windows PCI support.

I expect Windows support in flashrom to need ~60 lines of code, maybe
less. The device driver (and libpci support) is a different question,
If you have to modify any file except hwaccess.c, hwaccess.h, physmap.c
or Makefile please tell us.

If you have any questions, feel free to ask at flashrom at flashrom.org or
in #flashrom on irc.freenode.net.



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