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author | Maciej W. Rozycki <macro@orcam.me.uk> | 2022-03-31 10:11:05 +0300 |
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committer | Thomas Gleixner <tglx@linutronix.de> | 2022-04-10 13:48:14 +0300 |
commit | b584db0c84db5ed9230356d5fa6610de55d297e6 (patch) | |
tree | b6a5142e0028459c49f7eae029d95ac4b2f1e3ff /arch/x86/include/asm/pci_x86.h | |
parent | ac7cd5e16df8696c39e29b03dfedf069a025b822 (diff) | |
download | linux-b584db0c84db5ed9230356d5fa6610de55d297e6.tar.xz |
x86/PCI: Add $IRT PIRQ routing table support
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@orcam.me.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com> # crosvm
Link: https://lore.kernel.org/r/alpine.DEB.2.21.2203302228410.9038@angie.orcam.me.uk
Diffstat (limited to 'arch/x86/include/asm/pci_x86.h')
-rw-r--r-- | arch/x86/include/asm/pci_x86.h | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/x86/include/asm/pci_x86.h b/arch/x86/include/asm/pci_x86.h index a0627dfae541..1307cd689d2a 100644 --- a/arch/x86/include/asm/pci_x86.h +++ b/arch/x86/include/asm/pci_x86.h @@ -93,6 +93,15 @@ struct irq_routing_table { struct irq_info slots[]; } __attribute__((packed)); +struct irt_routing_table { + u32 signature; /* IRT_SIGNATURE should be here */ + u8 size; /* Number of entries provided */ + u8 used; /* Number of entries actually used */ + u16 exclusive_irqs; /* IRQs devoted exclusively to + PCI usage */ + struct irq_info slots[]; +} __attribute__((packed)); + extern unsigned int pcibios_irq_mask; extern raw_spinlock_t pci_config_lock; |