directio for flashrom

[Carl-Daniel Hailfinger]

Hi Jernej,

I saw that you sent a pciutils/libpci patch to support your Direct IO
driver on Windows.
flashrom is a GPL'ed utility to read/write flash chips, e.g. the one
storing BIOS/EFI on a mainboard.
Right now, flashrom is quite limited on Windows: It doesn't support
anything which needs MMIO/IOPort access. While it would be possible to
use WinIo, the WinIo license seems to be a bit odd and may be
incompatible with the GPL. Your Direct IO driver has the advantage of
being GPL, but it is missing a key feature needed by flashrom: Mapping
physical memory to the application (similar to MapPhysToLin in WinIo).
flashrom needs uncached mappings of device memory regions, and cached
mappings of RAM regions storing DMI info. I'm not sure whether
NtMapViewOfSection would already be enough for this purpose, or if your
Direct IO driver would have to be extended to offer such functionality.

Regards,
Carl-Daniel

[Darmawan Salihun]

On 7/6/12, Carl-Daniel Hailfinger  wrote:
> Hi Jernej,
>
> I saw that you sent a pciutils/libpci patch to support your Direct IO
> driver on Windows.
> flashrom is a GPL'ed utility to read/write flash chips, e.g. the one
> storing BIOS/EFI on a mainboard.
> Right now, flashrom is quite limited on Windows: It doesn't support
> anything which needs MMIO/IOPort access. While it would be possible to
> use WinIo, the WinIo license seems to be a bit odd and may be
> incompatible with the GPL. Your Direct IO driver has the advantage of
> being GPL, but it is missing a key feature needed by flashrom: Mapping
> physical memory to the application (similar to MapPhysToLin in WinIo).
> flashrom needs uncached mappings of device memory regions, and cached
> mappings of RAM regions storing DMI info. I'm not sure whether
> NtMapViewOfSection would already be enough for this purpose, or if your
> Direct IO driver would have to be extended to offer such functionality.
>
> Regards,
> Carl-Daniel
>
> flashrom mailing list
> [e-mail]
> http://www.flashrom.org/mailman/listinfo/flashrom

Hi Carl-Daniel,

Is there any update on the Windows driver now?

I just checked the possibility to provide memory-mapped access to the MMIO area
in Windows Vista/7 and the upcoming Windows 8.
However, I found that the programming model both in both versions are
at odd with
the memory-mapped direct access in Linux. The driver I conceived back
then works indeed,
but it's a kludge (quick hack) and have possibility to render the
system unstable.

I'll get back with more info later. But, for now I have to think over
the programming model
again and how to present it in Linux/Unix-friendly form.

Regards,

Darmawan