On 3/31/22 10:11, Maciej W. Rozycki wrote: > Handle the $IRT PCI IRQ Routing Table format used by AMI for its BCP > (BIOS Configuration Program) external tool meant for tweaking BIOS > structures without the need to rebuild it from sources[1]. > > The $IRT format has been invented by AMI before Microsoft has come up > with its $PIR format and a $IRT table is therefore there in some systems > that lack a $PIR table, such as the DataExpert EXP8449 mainboard based > on the ALi FinALi 486 chipset (M1489/M1487), which predates DMI 2.0 and > cannot therefore be easily identified at run time. > > Unlike with the $PIR format there is no alignment guarantee as to the > placement of the $IRT table, so scan the whole BIOS area bytewise. > > Credit to Michal Necasek for helping me chase documentation for the > format. > > References: > > [1] "What is BCP? - AMI", <https://www.ami.com/what-is-bcp/> > > Signed-off-by: Maciej W. Rozycki <macro@xxxxxxxxxxx> > Cc: Michal Necasek <mnecasek@xxxxxxxxx> > --- > Changes from v3: > > - Correct the BIOS memory scan such as to verify that the PCI IRQ Routing > Table header as well as individual slot entries are all wholly contained > within the BIOS memory area. > > - Following commit 5224f7909617 ("treewide: Replace zero-length arrays > with flexible-array members") also make `slots' in `irt_routing_table' a > flexible-array member. > > New change in v3. > --- > arch/x86/include/asm/pci_x86.h | 9 ++++ > arch/x86/pci/irq.c | 76 +++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 85 insertions(+) Tested-by: Dmitry Osipenko <dmitry.osipenko@xxxxxxxxxxxxx> # crosvm
